- Email: [email protected]
Risk factors for wound morbidity after open retromuscular (sublay) hernia repair
ARTICLE IN PRESS
Risk factors for wound morbidity after open retromuscular (sublay) hernia repair Clayton C. Petro, MD, Natasza M. Posielski, MD, Siavash Raigani, MD, Cory N. Criss, MD, Sean B. Orenstein, MD, and Yuri W. Novitsky, MD, Cleveland, OH
Background. Retrorectus repairs (RR) of abdominal wall hernias are growing in popularity, yet wound morbidity and predictors in this context have been characterized poorly. Models aimed at predicting wound morbidity typically do not control for technique and/or location of mesh. Our aim was to describe wound morbidity and risk factors specifically in the context of RR hernia repair. Our hypothesis was that the incidence of wound morbidity with mesh sublay would be less than predicted by a model that does not control for mesh position. Methods. Consecutive RR hernia repairs with at least a 90-day follow-up were identified in our prospective database and analyzed. The primary outcome measures were the incidence of surgical-site occurrence (SSO) and surgical-site infection (SSI) via modern, standardized definitions. For predictors of SSO, statistical analysis was performed with univariate analysis, v2, and logistic regression as well as multivariate regression. Results. A total of 306 patients met the inclusion criteria. Eighty-four SSOs identified in 72 (23.5%) patients included 48 (15.7%) SSIs, 14 (4.6%) instances of wound cellulitis, 12 (3.9%) skin dehiscences, 6 (2.0%) seromas, and 4 (1.3%) hematomas but no instances of mesh excision or fistula formation. Treatment entailed antibiotics alone in 30 patients, 14 bedside drainage procedures, 9 radiographically assisted drainage procedures, and 10 returns to the operating room for debridement. After multivariate analysis, diabetes (OR 2.41), hernia width >20 cm (OR 2.49), and use of biologic mesh (OR 2.93) were statistically associated with the development of a SSO (P < .05). Notably, the mere presence of contamination was not independently associated with wound morbidity (OR 1.83, P = .11). SSO and SSI rates anticipated by a recent risk prediction model were 50–80% and 17–83%, respectively, compared with our actual rates of 20–46% and 7–32%. Conclusion. Based on a large cohort of patients, we identified factors contributing to SSOs specifically for RR hernia repairs. Paradoxically, biologic mesh was an independent predictor of wound morbidity. The development of clinically important mesh complications and rates of wound morbidity less than anticipated by recent predictive models suggest that the retromuscular (sublay) mesh position may be more advantageous. (Surgery 2015;j:j-j.) From the Case Comprehensive Hernia Center, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH
DESPITE THE FREQUENCY OF INCISIONAL HERNIA REPAIR IN United States, approaches to repair vary widely.1 Although mesh reinforcement has been shown to decrease recurrence rates, positioning of the mesh relative to the musculofascial components of the abdominal wall remains debatable.2,3
THE
Accepted for publication May 12, 2015. Reprint requests: Yuri W. Novitsky, MD, Professor of Surgery, Department of Surgery, University Hospitals Case Medical Center, 11100 Euclid Avenue, LKS 5047, Cleveland, OH 44106-5047. E-mail: [email protected]. 0039-6060/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.surg.2015.05.003
Placement of mesh in the retromuscular/ retrorectus (RR) or sublay position was a technique promulgated by the French surgeons Rives and Stoppa in the 1970s.4,5 By 1991, Wantz reported the first US series using this technique.6 Since then, more than 30 reports have reinforced the low rates of recurrence (0–32%) and morbidity (2–25%) associated with RR mesh placement.7 Specifically, the technique benefits from a wide mesh overlap, ‘‘face-to-face’’ anterior/posterior muscle/fascia-mesh interfaces to promote tissue integration from vascularized tissues (as opposed to subcutaneous fat), restoration of a medial insertion point for lateral musculature, and reinforcement of the visceral sac without direct exposure SURGERY 1
ARTICLE IN PRESS 2 Petro et al
of the abdominal viscera to a foreign body.8-11 Mounting evidence supporting the positioning of mesh as a sublay has led some to consider it as the ‘‘gold standard’’ for incisional hernia repair.12,13 More recently, several modifications to the traditional Rives-Stoppa technique have been developed to provide additional lateral dissection beyond the rectus sheath. Several years ago, we presented our early experience with a novel technique for posterior component separation utilizing the transversus abdominis muscle release (TAR) to gain additional lateral retro-muscular dissection beyond the linea semilunari.14 The key features of TAR is creation of a large space for sublay mesh placement as well as the associated myofascial release with subsequent medialization of the rectus abdominis muscles, but without compromising the neurovascular integrity of the abdominal wall.14 Importantly, the aforementioned principles and benefits of the retromuscular mesh placement are maintained. Although the chief outcome measure in most reports of RR repair is recurrence, wound morbidity is uniformly important, particularly given its high cost and potential association with prosthetic infection.15-17 Unfortunately, wound morbidity has traditionally been characterized poorly in most reports of hernia repair, and reported cohorts of patients undergoing RR mesh sublay are not unique in this regard. Modern definitions of surgical-site occurrence (SSO) and surgical-site infection (SSI) as defined by the Ventral Hernia Working Group (VHWG) and Centers for Disease Control and Prevention (CDC), respectively, were only standardized recently.18 Ironically, recent attempts to characterize properly wound morbidity and its risk factors have been done in large cohorts of hernia repairs with no control for technique.19-21 One recently proposed model designed to assign SSO and SSI risks after open repair did not account for position of the mesh within the abdominal wall.20 Such a system would make a potentially erroneous assumption that RR repairs carry the same risk factors for wound morbidity as other open repairs and ‘‘might’’ predict inaccurately the expected rates of wound morbidity. Therefore, our aim was to characterize wound morbidity and its predictors specifically in the context of RR hernia repair. Furthermore, we hypothesized that the incidence of wound morbidity with mesh sublay would be less than predicted by the proposed model that does not account for the anatomic positioning of the mesh.
Surgery j 2015
METHODS A prospectively maintained, institutional review boardapproved database was used to identify all patients who underwent ventral hernia repairs between January 2009 and July 2013 at a tertiary care Hernia center. Typically, data entry was performed by the attending surgeon at the time of the operation. Postoperative events regarding wound morbidity were recorded subsequently by the attending surgeon during clinic follow-up. Inclusion criteria for the study were all patients who received RR repairs. This series included the traditional Rives-Stoppa repair alone or supplemented with a TAR with at least 90-day follow-up. Patients who underwent a concurrent panniculectomy were excluded, because they carry additional important confounding risks for wound morbidity that cannot be attributed to the hernia repair/mesh positioning alone.22 We analyzed preoperative demographics, comorbidities, operative characteristics, and postoperative outcomes of the patients. Data were supplemented with the use of electronic medical records when necessary. Demographics included patient age, sex, body mass index (BMI), number of previous abdominal operations, number of previous ventral hernia repairs, and previous history of a wound/mesh infection, as well as comorbidities, such as chronic obstructive pulmonary disease (COPD), history of smoking, active smoking (defined as smoking within 1 month of operation), and immunosuppression (defined as recent chemotherapy or taking oral antirejection medicines for solid organ transplants). Furthermore, we obtained perioperative data, such as the American Society of Anesthesiologists score, type of mesh, and defect size. The guidelines of the CDC were used to assign perioperative wounds into the 4 categories of clean, clean-contaminated, contaminated, and dirty. All patients were also stratified based on the 3-tier, modified Ventral Hernia Working Group system developed by Kanters et al.19 Grade 1 included patients with a low risk of complications and no history of wound infection. Grade 2 included patients with co-morbidities, such as obesity (BMI> 30), COPD, diabetes mellitus (DM), or smoking, as well as those patients with a history of previous wound infection. Grade 3 included patients with contaminated wound sites; Grade 3 was further stratified based on level of contamination according to the CDC categories of (A) clean-contaminated, (B) contaminated, and (C) active infection.
ARTICLE IN PRESS Surgery Volume j, Number j
Patient care and operative technique. Standardized patient care included medical optimization by our center for perioperative medicine that included but was not limited to: assessment of the cardiopulmonary risk, screening for diabetes management (hemoglobin A1C < 9), smoking cessation, universal screening for methicillinresistant Staphylococcus aureus (MRSA), and screening for sleep apnea. Cessation of smoking was required a minimum of 4 weeks before the operation and was confirmed with blood tests when necessary. Diabetics with an A1C $9% were referred to an endocrinologist and rescheduled once the diabetes was better controlled. Universal MRSA decolonization was used in all patients: every patient received intranasal mupirosin for 3 days before operation and a chlorhexidine bath the night before the operation. Those who screened positive for MRSA on a nasal swab were given a dose of preoperative vancomycin in addition to standard antimicrobial prophylaxis limited to 24 hours postoperatively. Operations all consisted of a traditional RivesStoppa RR dissection. When this type of fascial release was not sufficient for medialization of the medial aspect of the anterior rectus fascia, our previously described TAR14 (in contrast to the anterior component separation) was used to supplement the lateral dissection. The TAR allows for additional myofascial release and a wider space for mesh overlap in an avascular plane lateral to the linea semilunaris that does not disrupt the neurovascular integrity of the abdominal wall and does not require a different plane of dissection or another larger incision.14 After closure of the visceral sac, the prosthesis is placed within the retromuscular space for reinforcement before closure of the anterior rectus fascia over the prosthesis. The visceral sac is reapproximated with running 2-0 absorbable suture, the anterior fascia with running #1 slowly absorbable monofilament suture, and the skin with a running 4-0 monofilament absorbable subcuticular stitch or staples. Two closed-suction drains are placed above the retromusclar prosthesis and are maintained until their individual daily output is < 30 mL. Outcomes. The primary outcome used for analysis was the occurrence of an SSO. An SSO was defined as wound cellulitis, an SSI, seroma requiring an intervention, skin dehiscence, hematoma, or formation of enterocutaneous fistula. SSIs were further specified as superficial, deep, or organ space based on definitions from the Centers for Disease Control and Prevention. Although all SSIs required intervention, only
Petro et al 3
seromas/hematomas that required an intervention were characterized as such regardless of location. If not documented on the initial hospital stay, patients were instructed to follow-up at 2 weeks, 3 months, 6 months, and 1 year and then annually. Univariate analysis was used to identify variables associated with development of an SSO. Those variables with an association (P # .05) were entered into a multivariate analysis using binary logistic regression to identify factors that continued to demonstrate independent associations with SSO. Risks factors for SSIs were analyzed. Finally, we used our patient and operative characteristic to assign a ventral hernia risk score (VHRS) as defined by Berger et al.20 We then identified rates of SSO and SSI for the appropriate risk group and compared these rates to the rates anticipated by their scoring system. Data analysis was done using SPSS version 21 (SPSS IBM, Armonk, NY). Continuous variables were evaluated using descriptive statistics, whereas categorical variables were summarized by the use of frequency and percentages. Statistical analysis was performed using v2 and logistic regression as well as multivariate regression when appropriate. RESULTS Three hundred six patients undergoing abdominal wall reconstruction/incisional hernia repair with RR mesh placement were analyzed. Mean follow-up was 6.5 months (3–39). Patient demographics and operative characteristics are summarized in Table I. One patient developed intestinal necrosis (likely due to a thromboembolic event) with gross spillage of bowel contents on postoperative day 5 requiring reoperation, a bowel resection, and mesh explantation. This patient was excluded for analysis, because her mesh excision was not related to wound morbidity. All patients underwent a RR repair, with 62 (20%) undergoing a Rives-Stoppa RR repair alone and 244 (80%) had a TAR as well. Clean cases were present in 192 (62.7%) of the cohort, 33 (10.7%) of whom had no comorbidities (modified Ventral Hernia Working Group [mVHWG] Grade 1) and 152 (52%) of whom had medical comorbidities (mVHWG Grade 2). The remaining cases consisted of 43 (14.1%) clean-contaminated, 36 (11.8%) contaminated, and 35 (11.4%) infected fields (mVHWG Grades 3ac, respectively). The infected patients included those with active draining sinuses and enteroprosthetic and enterocutaneous fistulae. Regarding all contaminated cases (n = 114), biologic mesh was used in 70 (61%), constituting 96% (70/73) of all biologic mesh usage. Synthetic
ARTICLE IN PRESS 4 Petro et al
Surgery j 2015
Table I. Patient demographics and operative characteristics Variable Mean age Female Mean BMI Mean ASA Diabetes mellitus COPD Smoking history History of a wound infection Immunosuppression Mean no. abdominal operations Mean no. previous hernia repairs Mean hernia width, cm Mean hernia area, cm2 Rives-Stoppa/TAR Mean OR time, min Biologic/synthetic mesh Biologic mesh/mVHWG Grade 3ac Synthetic mesh/mVHWG Grade 3ac Clean mVHWG grade 1 mVHWG grade 2 Clean-contaminated, mVHWG Grade 3a Contaminated, mVHWG Grade 3b Infected, mVHWG Grade 3c*
Mean ± SD/ frequency (%) 57 ± 12 162/306 (53%) 34.4 ± 8.3 3 ± 0.4 40/306 (13.1%) 38/306 (8%) 40/36 (13.1%) 143/306 (43.8%) 18/306 (5.9%) 3.8 ± 3.1 1.8 ± 2.5 14.6 ± 5.7 329 ± 221 62/244 (20%/80%) 194 ± 80 73/233 (24%/76%) 70/114 (61.4%) 44/114 (38.6%) 192 33 159 43
(62.7%) (10.7%) (52.0%) (14.1%)
36 (11.8%) 35 (11.4%)
*Includes active infection/draining sinuses, enteroprosthetic, enterocutaneous and enteroatmospheric fistulae. ASA, American Society of Anesthesiologists; BMI, body mass index; COPD, chronic obstructive pulmonary disease; mVHWG, modified Ventral Hernia Working Group; OR, operating room; TAR, transversus abdominis muscle release.
mesh was used in the remaining 44 (39%) cases, 28 of which were clean-contaminated, 11 were contaminated, and 5 were infected. SSO and SSI. A total of 84 SSOs were identified in 72 patients, summarized in Tables II and III. Some patients had more than one SSO; the incidence of having an SSO was 24% (72/306) with 4% (13/306) of patients having multiple SSOs. SSOs consisted of 48 SSIs (48/306, 16%), 14 instances of wound cellulitis (14/306, 5%), 12 instances of skin dehiscence (12/306, 4%), 6 seromas requiring intervention (6/306, 2.0%), and 4 hematomas (4/306, 1%). There have been no instances of mesh excision or enterocuteous fistula formation to date. Instances of wound cellulitis as defined by the criteria of the CDC were treated with antibiotics
Table II. SSOs: breakdown and incidence SSOs (n = 84) SSI: 48 Wound cellulitis: 14 Seroma: 6 Skin dehiscence: 12 Hematoma: 4
Percentage of all SSOs 57% 17% 7% 15% 4%
(48/84) (14/84) (6/84) (12/84) (4/84)
Incidence of SSO 16% 5% 2% 4% 1%
(48/306) (14/306) (6/306) (12/306) (4/306)
SSI, Surgical-site infection; SSO, surgical-site occurrence.
Table III. SSOs by treatment Wound cellulitis (n = 14) Skin dehiscence (n = 12)
Seroma (n = 6) Hematoma (n = 4)
Superficial SSI (n = 22) Deep SSI (n = 26)
Antibiotics: 14 Packing: 9 Delayed primary closure: 1 Wound VAC: 1 OR debridement: 1 IR drainage: 4 I&D: 2 OR drainage: 2 IR drainage: 1 I&D: 1 Antibiotics: 15 I&D: 7 I&D: 5 IR drainage: 14 OR debridement: 7
I&D, Bedside Incision and Drainage; IR, Drainage by Interventional Radiology; OR, operating room; SSI, surgical-site infection; SSO, surgical-site occurrence; VAC, Negative Pressure Wound Therapy.
and resolved without progression in all 14 patients. For the 12 instances of skin dehiscence, wet-to-dry packing alone was used in 75% (9/12) of patients, one of whom required operative debridement of necrotic skin and one patient was treated with a vacuum-based dressing, and another underwent delayed primary closure. Finally, of the 4 hematomas, 1 was drained by interventional radiology, 1 was drained at the bedside, and 2 were drained in the operating room. Six seromas required an intervention. Four underwent IR drainage, and 2 were drained at the bedside. All cultures from the seroma samples were sterile, and the events were thus not considered as SSI. Regarding the 48 SSIs, 22 were superficial, and 26 were deep. Superficial SSIs were treated with antibiotics alone in 68% (15/22) of patients and by bedside debridement (wound opening) in the remaining 32% (7/22) of instances. Of the deep SSIs, 54% (14/26) were treated by IR drainage, 19% (5/26) by bedside drainage, and 27% (7/26) with operative debridement. All 19 IR drains were removed eventually and did not need to be replaced. All instances of skin dehiscence or superficial SSI treated with bedside
ARTICLE IN PRESS Petro et al 5
Surgery Volume j, Number j
or operative debridement followed by dressing changes healed fully within 6 months of the operation. We analyzed in detail the 12 deep SSIs that required either bedside or operative debridement with resultant mesh exposure. In a subanalysis of these patients, 6/12 contained noncrosslinked porcine dermis biologic mesh. Of those, 5 of the wounds healed completely within 6 months, 1 had a small draining sinus that resolved completely after 12 months. In the remaining 6 instances, uncoated synthetic mesh was exposed. Three patients had mid-weight polypropylene and 3 had multifilament polyester. All were treated with a combination of wet-to-dry and vacuum-based dressings. Three of these patients had chronically draining sinuses (all had multifilament polyester mesh). These patients with the chronic draining sinuses continued to have periods of transient skin healing with episodes of intermittent wound drainage controlled with a dry dressing. One other patient had a stitch abscess that required removal of a suture, whereas another was found to have a small subcutaneous piece of sponge from the vacuum dressing, and the last patient died from recurrence of a hematologic malignancy within a year of her operation. Predictors of SSO. Univariate analysis was performed to determine which factors were associated with SSO Table IV. Morbid obesity (BMI >35 kg/m2; OR 1.04, P = .012), DM (OR 3.79, P # .0001), smoking (OR 2.89, P = .0026), number of previous abdominal operations (OR 1.10, P = .019), hernia width (OR 1.08, P = .002), hernia area greater than 200 cm2 (OR 1.87, P = .05), use of biologic mesh (OR = 4.64, P # .0001), and presence of contamination (mVHWG Grade 3, OR = 3.84, P # .0001) were found to be statistically associated with SSOs. Sex, age, American Society of Anesthesiologists (ASA) Classification class, history of wound infection, COPD, immunosuppression, use of a TAR, and number of previous hernia repairs were found to have no association with the development of an SSO. Using the modified VHWG grading scale, we found 2 SSOs in 2 of 33 (6%) Grade 1 patients, 31 SSOs were found in 26 of 159 (16%) grade 2 patients, and 52 SSOs were found in 44 of 114 (39%) grade 3 patients. There were no differences between Grades 1 and 2 (P = .18), but there were between Grades 2 and 3 (P # .0001). The 2 SSOs in the Grade 1 hernia group were one SSI and one instance of wound cellulitis. In the patients with Grade 2 hernias, there were 8 superficial SSI, 7 deep SSI, 4 seromas, 6 wound dehiscences, 1 hematoma, and 5 wound cellulitis. In Grade 3
Table IV. Predictors of SSO: univariate analysis Variable Age Female Morbid obesity (BMI >35 kg/m2) ASA Diabetes mellitus COPD Smoking History of wound infection Immunosuppression No. abdominal operations No. previous hernia repairs Hernia width #10 vs >10 cm #20 vs >20 cm <10 vs 10–20 vs >20 As a continuous variable Hernia area #200 vs >200 cm2 TAR (vs Rives-Stoppa) Biologic mesh Contamination (mVHWG Grade 3)
Odds ratio (95% CI)
P value
0.98 (0.96–1.00) 0.66 (0.39–1.13) 1.04 (1.01–1.07)
.12 .13 .012
3.79 1.63 2.89 1.65 1.72 1.10 1.09
NA (2.11–6.81) (0.78–3.44) (1.44–5.78) (0.96–2.82) (0.62–4.75) (1.02–1.20) (0.99–1.20)
3.03 (1.04–8.83) 2.27 (1.24–4.13) NA 1.08 (1.03–1.13) 1.87 1.54 4.64 3.84
(0.98–3.57) (0.74–3.09) (2.55–8.46) (2.21–6.69)
.23 <.0001 .19 .003 .07 .30 .02 .08 .042 .008 .009 .002 .05 .24 <.0001 <.0001
Values in bold indicate a P value #0.05. ASA, American Society of Anesthesiologists; BMI, body mass index; COPD, chronic obstructive pulmonary disease; mVHWG, modified Ventral Hernia Working Group; NA, not available; SSO, surgical-site occurrence; TAR, transversus abdominis muscle release.
hernia patients, there were 13 superficial SSI, 19 deep SSI, 6 skin dehiscences, 3 hematomas, 1 seroma, 8 instances of wound cellulitis, and our 1 organ space infection (intraperitoneal abscess). Factors demonstrating independent associations with SSO after multivariate analysis using binary logistic regression included DM (P = .013, OR 2.41), defect width >20 (P = .012, OR 3.11), and use of biologic mesh (P = .010, OR 2.93). Alternatively, morbid obesity, smoking history, number of previous abdominal operation, and presence of contamination, while statistically significant in univariate analysis, were not statistically significant in multivariate analysis (Table V). Contaminated field and active infection were associated with a development of SSI (P < .0001) (Fig 1). Using the scoring system proposed by Berger et al, we assigned each of our 306 patients a VHRS for SSO and SSI. Regarding the VHRS for SSO, our rates of SSO were 20% (55/271) and 46% (16/35) for Groups II and III, respectively (Fig 2, A). For the VHRS for SSI, our rates of SSI were 7% (5/ 54), 10% (15/149), 21% (9/42), 32% (11/34)
ARTICLE IN PRESS 6 Petro et al
Surgery j 2015
Table V. Independent predictors of SSO after multivariate analysis Variable
Odds ratio
P value
DM Morbid obesity (BMI>35 kg/m2) Smoking history Width >20 cm No. abdominal operations Biologic mesh Contamination (mVHWG Grade 3)
2.41 (1.21–4.80) 1.01 (0.96–1.05)
.013 .545
2.14 2.49 1.03 2.93 1.83
.061 .012 .564 .010 .110
(0.97–4.73) (1.23–5.05) (0.94–1.13) (1.29–6.64) (0.87–3.82)
Values in bold indicate statistical significance. BMI, Body mass index; mVHWG, modified Ventral Hernia Working Group; SSO, surgical-site occurrence.
for Groups II-V respectively. These rates are shown against anticipated rates reported by Berger et al in Fig 2, B. DISCUSSION Retromuscular repairs with sublay mesh reinforcement continue to gain in popularity, yet risk factors for wound morbidity have not been defined. Models designed to risk-stratify patients by their potential of developing an SSO or SSI do not control for technique, and may assign an inappropriate risk to the RR repairs. In this study, we identified specific risk factors for wound morbidity in the context of open hernia repair with mesh sublay. Importantly, we demonstrated superior outcomes compared with rates of wound morbidity predicted by a recently developed, riskstratification model by Berger et al20 that does not control for mesh location. These findings support RR mesh placement in open VHR with regard to wound morbidity. Wound morbidity has been poorly characterized traditionally in reports of RR hernia repair. In 34 reports of mesh sublay from 1989 to 2013, 7 did not mention wound morbidity specifically (Table VI).5,6,8-11,14-16,23-47 In many other reports, distinctions between wound cellulitis or ‘‘wound sepsis’’ and the CDC classifications of SSI are ambiguous. Modern definitions of SSO and SSI as defined by the VHWG and CDC have only become used commonly in recent years. These classifications were either unavailable or underused, resulting in a wide range of reported rates of SSO (2.5–30%) and SSI (2.2–23.8%) within the aforementioned data. Our cohort represents a variety of comorbidities and the presence of contamination in many cases. Using strict adherence to modern definitions of SSO/SSI,
Fig 1. Surgical site infection rates in our cohort of Retromuscular repairs according to modified VHWG scale. There was a significantly higher rate of SSI in the Groups 3b and 3c when compared to Groups 1-2 and 3a.
Fig 2. Comparison of SSO (A) and SSI (B) rates in our cohort versus Ventral Hernia Risk Score (VHRS).
we found rates of 15%/8% in clean cases and 39%/36% in contaminated counterparts. This report encompasses a comprehensive experience of mesh sublay to date and provides a candid assessment of wound morbidity in this context. After multivariate analysis, the presence of DM, hernia width >20 cm, and use of biologic mesh were found to be independent risk factors for wound morbidity. The association of wound morbidity with biologic mesh but not with contamination was possibly a reflection of our tendency to use a
ARTICLE IN PRESS Petro et al 7
Surgery Volume j, Number j
Table VI. Previously reported rates of wound morbidity after RR mesh placement First author, ref
Year
N
#SSO/SSI rate (SSO%)
Mesh excision
Stoppa10 Wantz6 Rives5 Amid23 Liakakos24 McLanahan11 Schumpelick25 Luijendijk16 Martin-Duce26 Bauer9 Flament27 Ferranti28 Langer29 Petersen30 Sriussadaporn31 Kingsnorth32 Paajanen33 Novitsky34 Israelsson35 Lomanto36 Notash37 Iqbal15 Berry38 Williams39 Wheeler8 Manigrasso40 Abdollahi41 Mehrabi42 Forte43 Fei44 Maman45 Novitsky14 Str^ambu46 Schroeder47
1989 1991 1992 1994 1994 1997 1999 2000 2001 2002 2002 2003 2003 2003 2003 2004 2005 2006 2006 2006 2007 2007 2007 2008 2008 2009 2010 2010 2011 2012 2012 2012 2013 2013
368 30 258 54 102 86 146 84 152 57 693 35 155 175 9 33 84 128 228 50 86 254 47 115 90 30 312 176 246 26 89 42 45 93
16 (12%) NR 20 (8%) NR NR 16 (18%) 41/5 (28%, 3%) 3 (4%) 17 (11%) 2 (4%) 17 (3%) 5 (14%) NR 14 (8%) NR NR 13/5 (15%, 6%) 3 (2%) NR 6/3 (12%, 6%) 14/13 (16%, 15%) 33/10 (13%, 4%) 12/4 (26%, 9%)zz 27/6 (24%, 5%) 9/6 (10%, 7%) 9/5 (30%, 17%) 28/7 (9%, 2%) 8/5 (5%, 3%) 12/8 (5%, 3%) 5/1 (19%, 4%){{ 8/4 (9%, 5%) 10/10 (24%) 3 (2%) 6/0 (7%)
0 0 NR NR NR NR (4.1%) & 0 (4.6%) (3.5%)* (0.001%)y (2.8%)z NR (1.7%)x 0 (3.0%) (1.2%){ (0.01%)** NR (4%) (1.2%) (2.0%)yy 0 (3%) (5.6%)xx NR (0.003%) (1.1%) NR NR (3.4%) 0 0 0
6 7 2 1 1 3 1 1 1 2 1 5 3 5 1 2
3
*2, both ePTFE mesh. y1, polyester. z1, polypropylene. x3, all ePTFE. {1, partial mesh excision. **1, partial mesh excision–lightweight polypropylene. yy5, all mesh removed within 30 d of operation after deep SSI. zzAll had a concurrent panniculectomy. xx5, all partial excision of polyester. {{Concurrent intraperitoneal mesh. ePTFE, Expanded polytetrafluoroethylene; NR, not reported; SSI, surgical-site infection. In bold are SSO and SSI rates (as a percentage) respectively. When SSO and SSI are not distinguished, they are reported as a single value. & - 4 coated lightweight mesh and 2 heavyweight polypropylene.
biologic mesh in the most contaminated scenarios. Only 3 of the 62 cases in which biologic mesh was used were clean surgical fields; the remaining constituted 14 clean-contaminated, 18 contaminated, and 27 infected cases. Nevertheless, an SSO rate of 48% (30/62) with use of biologic mesh is low when compared with other reports, which cite wound morbidity rates as great as 87% when biologic mesh was used for ventral hernia repair.48-51
Of these 30 SSOs, 17 were SSIs, which is in line with CDC estimates of acceptable rates given the relative degree of contamination. Not surprisingly, we found that contaminated and actively infected fields were statistically more like to be associated with an SSI. Ultimately, the ongoing prospective studies comparing biologic prosthetics with synthetic mesh in contaminated surgical fields will provide guidance in these difficult situations. The
ARTICLE IN PRESS 8 Petro et al
benefits of mesh sublay and favorable characteristics of uncoated polypropylene warrant specific discussion, because these factors may remove the stigma of what many considered a surgical faux pas, ie, use of synthetic mesh in contaminated fields, the feasibility of which has been demonstrated recently by Carbonell et al.52 Retrorectus repairs may be beneficial for several reasons. First, the mesh is positioned between 2 vascularized layers of the abdominal wall, allowing for tissue ingrowth on both sides of the prosthetic. Second, there is a fascial reconstruction ventral to the mesh and as a result, there is a ‘‘protective’’ layer of autogenous fascia/muscle between superficial SSOs and the underlying prosthesis, helping to prevent mesh involvement. Next, creation of an extraperitoneal pocket, first in the retro-rectus space and supplemented with TAR when necessary, allows for lateral dissection into the retroperitoneuml; this RR space allows for wide reinforcement of the visceral sac without exposing the viscera to direct contact with the mesh as in laparoscopic counterparts. Finally, both a traditional Rives-Stoppa with or without a TAR allows for substantial myofascial medialization without raising skin flaps maintaining all the perforating vessels or compromising the neurovascular integrity of the abdominal wall.14 Furthermore, a TAR allows for all the benefits of a RivesStoppa repair to be extrapolated to patients with larger hernias requiring additional myofascial medialization. We found that adding posterior component separation via TAR to the RR approach occurred without incurring greater wound morbidity. This lateral dissection in an avascular plane is in stark contrast to wide mesh onlays that require raising large, devascularized skin flaps to create a plane anterior to the myofascial components of the abdominal wall for onlay placement of the mesh. This concern stems from multiple reports of greater wound morbidity associated with placement of mesh as an onlay versus sublay.53,54 The benefits of the onlay technique in regard to lesser operative times with less technical difficulty must be weighed against the concern for superficial SSOs more easily involving the underlying mesh. The importance of choice of prosthesis cannot be overstated. Our current practice is to use mid-weight, monofilament, macroporous polypropylene mesh because of its demonstration of superior bacterial clearance in animal studies.55,56 Notably, of 41 meshes reported previously to require excision in the RR literature, 5 were ePTFE (laminar) and 6 were polyester (multifilament)
Surgery j 2015 meshes.7-9,30 Only one partial excision and one total excision of polypropylene was mentioned specifically, whereas the remaining were not specified (Table VI). The fear of chronic prosthetic infection is underscored by Iqbal et al,15 who reported the excision of 5 prosthetics within 30 days of the initial operation due to deep SSIs; all of those meshes were heavyweight polypropylene. Again, the character of macropourous monofilament mesh in the setting of good fascial coverage appears to be able to potentially overcome what was once thought of as a predestined chronic infection if the exposed mesh was not excised. Relevant data from Binneb€ osel et al. support better fibrous capsule formation and collagen deposition when synthetic mesh was placed in the sublay position compared to onlay.57 Theoretically, these characteristics correlated with better cellular penetration and potentially superior clearance of infection. We used synthetic mesh in clean-contaminated and contaminated instances with minimal gross spillage and have previously reported acceptable outcomes.52 We attribute these favorable choices of macroporous monofilament mesh coupled with bilaminar fascial coverage with our ability to obtain full wound closure in the 12 cases of deep SSI with exposed mesh without the need for mesh excision. It is important to note that 3 of the 12 patients (all with polyester mesh) had episodes of ‘‘relapse’’ drainage we believe to be related to chronic infection of the multifilament polyester prosthetic. Our poor experience with prolonged/recurrent draining sinuses in patients with exposed multifilament polyester mesh has resulted in our shift away from polyester during open repairs. Regarding biologic meshes, non-crosslinked prosthetics have also shown a decreased foreign body reaction and attenuated cytokine expression thought to be related to prosthetic encapsulation.58,59 The choice of both type of mesh and location are intimate factors when optimizing outcomes. Although we believe that macroporous polypropylene might be advantageous in the vast majority of patients, this study was not designed to test this hypothesis and should not be relied on to guide the choice of mesh. Identifying predictors of wound morbidity can aid surgeons in patient selection and optimization. Although DM was found to correlate most strongly after multivariate analysis, smoking, and morbid obesity are notorious contributors to postoperative wound morbidity.18,19 In our current practice, patients with diabetes found to have a hemoglobin A1c >9 during their preoperative
ARTICLE IN PRESS Petro et al 9
Surgery Volume j, Number j
assessment are postponed and referred to an endocrinologist for better glucose control.60 Morbidly obese patients are referred to a medical weight-loss specialist or bariatric surgery for weight loss to a BMI of <35. Smokers are required to abstain from smoking for at least 4 weeks.61 Although obesity and smoking were not found to be independently associated with wound morbidity after multivariate analysis, we believe that controlling these comorbidities demonstrates patient ownership of their health in the perioperative period. In fact, optimization of these comorbidities may in fact have quelled their impact on wound morbidity, as demonstrated by multivariate analysis. The persistent impact of DM on outcomes suggests that our HgA1c requirement should be stricter. In fact, recent studies suggest a level less than 8% is associated with decreased wound morbidity.62-64 We have modified our preoperative strategy subsequently in patients with diabetes to delay elective open repairs until HgA1C is less than 8%. Surgeons should identify high-risk patients and optimize medical comorbidities even when contemplating a RR repair. Currently we do not perform elective, open abdominal wall reconstructions in smokers or severely morbidly obese patients. Previous attempts to characterize wound morbidity and its predictors after hernia repair have been performed with cohorts with limited or no control for technique.19-21 These models operate under the assumption that all techniques carry the same incidence and risk factors for wound complications after repair. We hypothesized that this assumption was incorrect. Our report that generated a modification of the VHWG grading scale consisted of 299 repairs: 192 RR repairs, 58 were open anterior components separation, 37 laparoscopic anterior components separation, and 12 miscellaneous procedures. We found a trend toward improved morbidity rates for RR repair that did not gain statistical significance. Our current report adds an additional 124 RR repairs, generating morbidity rates of 6%, 16%, and 39% for grades 1–3, respectively, compared with our originally reported rates of 14%, 27%, and 46% when all techniques were included.19 Furthermore, to contrast our previous report, smoking, morbid obesity, COPD, previous hernia repair, history of wound infection, and hernia size >100 cm2 were not found to be predictors of SSO with RR mesh placement. A riskstratification model proposed recently by Berger et al. was created from 888 open hernia repairs and included both primary and incisional hernias.20 Their data were used to create a weighted scoring
system for risk factors associated most strongly with SSO and SSI. Using their model, our patients were assigned to the appropriate SSO and SSI risk group. Their model would predict SSO rates of 50% and 80% for Risk Groups II and III, respectively, whereas our patients had rates of 20% and 46%. Likewise, their model predicts SSI rates of 17–83% for Risk Groups II-V, whereas our counterparts resulted in rates from 7 to 32%. Clearly, RR repairs result in less wound morbidity compared with results anticipated by other models generated by non-RR data. As an example, skin flaps were identified as a significant predictor of wound morbidity in the aforementioned classification, emphasizing why technique and morbidity should not be dissociated. Our results undermine potentially the validity of the model by Berger et al20 and should caution its widespread use. Our study is limited by its retrospective and uncontrolled design as well as limited follow-up. Also, while the primary outcome measure of this analysis was perioperative wound morbidity, recurrence rates are the ultimate measure of the adequacy and durability of hernia repair. Although our follow-up of this retrospective cohort is limited, the absence of any mesh excisions which would lead to an inevitable recurrence is promising. Interestingly, the importance of predicting and preventing wound morbidity lies in the assumption that recurrence is a function of wound morbidity. Our report demonstrates that reasonable rates of wound morbidity can be overcome without obvious long-term sequelae like mesh excision. Therefore, not only might SSO and SSI rates be less than anticipated, the effects of wound morbidity may be less devastating than experienced with other techniques. In conclusion, RR mesh sublay appears to be unique in its ability to prevent and overcome wound morbidity, defying predictions by models generated from the non-RR techniques. Overall, we believe that RR repair may be a favorable approach to minimize wound complications during open hernia repairs. REFERENCES 1. Cassar K, Munro A. Surgical treatment of incisional hernia. Br J Surg 2002;89:534-45. 2. Paul A, Korenkov M, Peters S, Kohler L, Fischer S, Troidl H. Unacceptable results of the Mayo procedure for repair of abdominal incisional hernias. Eur J Surg 1998;164:361-7. 3. Burger JW, Luijendijk RW, Hop WC, Halm JA, Verdaasdonk EG, Jeekel J. Long-term follow-up of a randomized controlled trial of suture versus mesh repair of incisional hernia. Ann Surg 2004;240:578-83; . discussion 83-5.
ARTICLE IN PRESS 10 Petro et al
4. Stoppa R, Petit J, Abourachid H, Henry X, Duclaye C, Monchaux G, et al. Original procedure of groin hernia repair: interposition without fixation of Dacron tulle prosthesis by subperitoneal median approach. [in French]. Chirurgie 1973;99:119-23. 5. Rives J, Pire JC, Flament JB, Convers G. Treatment of large eventrations (apropos of 133 cases). [in French]. Minerva Chir 1977;32:749-56. 6. Wantz GE. Incisional hernioplasty with Mersilene. Surg Gynecol Obstet 1991;172:129-37. 7. Jin J, Rosen MJ. Laparoscopic versus open ventral hernia repair. Surg Clin North Am 2008;88:1083-100; viii. 8. Wheeler AA, Matz ST, Bachman SL, Thaler K, Miedema BW. Retrorectus polyester mesh repair for midline ventral hernias. Hernia 2009;13:597-603. 9. Bauer JJ, Harris MT, Gorfine SR, Kreel I. Rives-Stoppa procedure for repair of large incisional hernias: experience with 57 patients. Hernia 2002;6:120-3. 10. Stoppa RE. The treatment of complicated groin and incisional hernias. World J Surg 1989;13:545-54. 11. McLanahan D, King LT, Weems C, Novotney M, Gibson K. Retrorectus prosthetic mesh repair of midline abdominal hernia. Am J Surg 1997;173:445-9. 12. Forte A, Zullino A, Manfredelli S, Montalto G, Covotta F, Pastore P, et al. Rives technique is the gold stardard for incisional hernioplasty. An institutional experience. Ann Ital Chir 2011;82:313-7. 13. Pauli EM, Rosen MJ. Open ventral hernia repair with component separation. Surg Clin North Am 2013;93: 1111-33. 14. Novitsky YW, Elliott HL, Orenstein SB, Rosen MJ. Transversus abdominis muscle release: a novel approach to posterior component separation during complex abdominal wall reconstruction. Am J Surg 2012;204:709-16. 15. Iqbal CW, Pham TH, Joseph A, Mai J, Thompson GB, Sarr MG. Long-term outcome of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique. World J Surg 2007;31:2398-404. 16. Luijendijk RW, Hop WC, van den Tol MP, de Lange DC, Braaksma MM, IJzermans JN, et al. A comparison of suture repair with mesh repair for incisional hernia. N Engl J Med 2000;343:392-8. 17. Urban JA. Cost analysis of surgical site infections. Surg Infect 2006;7(Suppl 1):S19-22. 18. Ventral Hernia Working Group, Breuing K, Butler CE, Ferzoco S, Franz M, Hultman CS, et al. Incisional ventral hernias: review of the literature and recommendations regarding the grading and technique of repair. Surgery 2010;148:544-58. 19. Kanters AE, Krpata DM, Blatnik JA, Novitsky YM, Rosen MJ. Modified hernia grading scale to stratify surgical site occurrence after open ventral hernia repairs. J Am Coll Surg 2012;215:787-93. 20. Berger RL, Li LT, Hicks SC, Davila JA, Kao LS, Liang MK. Development and validation of a risk-stratification score for surgical site occurrence and surgical site infection after open ventral hernia repair. J Am Coll Surg 2013;217:974-82. 21. Fischer JP, Wink JD, Nelson JA, Kovach SJ 3rd. Among 1,706 cases of abdominal wall reconstruction, what factors influence the occurrence of major operative complications? Surgery 2014;155:311-9. 22. Harth KC, Blatnik JA, Rosen MJ. Optimum repair for massive ventral hernias in the morbidly obese patient–is panniculectomy helpful? Am J Surg 2011;201:396-400; . discussion.
Surgery j 2015
23. Amid PK, Shulman AG, Lichtenstein IL. Use of Marlex mesh in the repair of recurrent incisional hernia. Br J Surg 1994;81:1827. 24. Liakakos T, Karanikas I, Panagiotidis H, Dendrinos S. Use of Marlex mesh in the repair of recurrent incisional hernia. Br J Surg 1994;81:248-9. 25. Schumpelick V, Klosterhalfen B, Muller M, Klinge U. [Minimized polypropylene mesh for preperitoneal net plasty (PNP) of incisional hernias]. Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen 1999;70:422-30. 26. Martin-Duce A, Noguerales F, Villeta R, Hernandez P, Lozano O, Keller J, et al. Modifications to Rives technique for midline incisional hernia repair. Hernia 2001;5:70-2. 27. Flament JB, Palot JP, Lubrano D, Levy-Chazal N, Conce JP, Marcus C. [Retromuscular prosthetic repair: experience from France]. Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen. 2002;73:1053-8. 28. Ferranti F, Triveri P, Mancini P, Di Paola M. The treatment of large midline incisional hernias using a retromuscular prosthetic mesh (Stoppa-Rives technique). Chir Ital 2003; 55:129-36. 29. Langer C, Liersch T, Kley C, Flosman M, Suss M, Siemer A, et al. Twenty-five years of experience in incisional hernia surgery. A comparative retrospective study of 432 incisional hernia repairs. [in German]. Chirurgia 2003;74:638-45. 30. Petersen S, Henke G, Zimmermann L, Aumann G, Hellmich G, Ludwig K. Ventral rectus fascia closure on top of mesh hernia repair in the sublay technique. Plast Reconstr Surg 2004;114:1754-60. 31. Sriussadaporn S, Pak-Art R, Bunjongsat S. Immediate closure of the open abdomen with bilateral bipedicle anterior abdominal skin flaps and subsequent retrorectus prosthetic mesh repair of the late giant ventral hernias. J Trauma 2003;54:1083-9. 32. Kingsnorth AN, Sivarajasingham N, Wong S, Butler M. Open mesh repair of incisional hernias with significant loss of domain. Ann R Coll Surg Engl 2004;86:363-6. 33. Paajanen H, Laine H. Operative treatment of massive ventral hernia using polypropylene mesh: a challenge for surgeon and anesthesiologist. Hernia 2005;9:62-7. 34. Novitsky YW, Cobb WS, Kercher KW, Matthews BD, Sing RF, Heniford BT. Laparoscopic ventral hernia repair in obese patients: a new standard of care. Arch Surg 2006;141:57-61. 35. Israelsson LA, Smedberg S, Montgomery A, Nordin P, Spangen L. Incisional hernia repair in Sweden 2002. Hernia 2006;10:258-61. 36. Lomanto D, Iyer SG, Shabbir A, Cheah WK. Laparoscopic versus open ventral hernia mesh repair: a prospective study. Surg Endosc 2006;20:1030-5. 37. Yaghoobi Notash A, Yaghoobi Notash A Jr, Seied Farshi J, Ahmadi Amoli H, Salimi J, Mamarabadi M. Outcomes of the Rives-Stoppa technique in incisional hernia repair: ten years of experience. Hernia 2007;11:25-9. 38. Berry MF, Paisley S, Low DW, Rosato EF. Repair of large complex recurrent incisional hernias with retromuscular mesh and panniculectomy. Am J Surg 2007;194:199-204. 39. Williams RF, Martin DF, Mulrooney MT, Voeller GR. Intraperitoneal modification of the Rives-Stoppa repair for large incisional hernias. Hernia 2008;12:141-5. 40. Manigrasso A, Candioli S, Arcieri S, Palazzini G, Filippini A. Incisional hernia prosthetic surgery: a prospective study comparing laparoscopic and open techniques. [in Italian]. G Chir 2009;30:201-14. 41. Abdollahi A, Maddah GH, Mehrabi BM, Jangjoo A, Forghani MN, Sharbaf N. Prosthetic incisional
ARTICLE IN PRESS Surgery Volume j, Number j
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
hernioplasty: clinical experience with 354 cases. Hernia 2010;14:569-73. Mehrabi M, Jangjoo A, Tavoosi H, Kahrom M, Kahrom H. Long-term outcome of Rives-Stoppa technique in complex ventral incisional hernia repair. World J Surg 2010;34: 1696-701. Forte A, Zullino A, Manfredelli S, Montalto G, Bezzi M. Incisional hernia surgery: report on 283 cases. Eur Rev Med Pharmacol Sci 2011;15:644-8. Fei Y. Compound repair of intraperitoneal onlay mesh associated with the sublay technique for giant lower ventral hernia. Ann Plast Surg 2012;69:192-6. Maman D, Greenwald D, Kreniske J, Royston A, Powers S, Bauer J. Modified Rives-Stoppa technique for repair of complex incisional hernias in 59 patients. Ann Plast Surg 2012;68:190-3. Str^ambu V, Radu P, Bratucu M, Garofil D, Iorga C, Iorga R, et al. Rives technique, a gold standard for incisional hernias---our experience. Chirurgia 2013;108:46-50. Schroeder AD, Debus ES, Schroeder M, Reinpold WM. Laparoscopic transperitoneal sublay mesh repair: a new technique for the cure of ventral and incisional hernias. Surg Endosc 2013;27:648-54. Helton WS, Fisichella PM, Berger R, Horgan S, Espat NJ, Abcarian H. Short-term outcomes with small intestinal submucosa for ventral abdominal hernia. Arch Surg 2005; 140:549-60; . discussion 60-2. Bellows CF, Shadduck PP, Helton WS, Fitzgibbons RJ. The design of an industry-sponsored randomized controlled trial to compare synthetic mesh versus biologic mesh for inguinal hernia repair. Hernia 2011;15:325-32. Harth KC, Rosen MJ. Major complications associated with xenograft biologic mesh implantation in abdominal wall reconstruction. Surg Innov 2009;16:324-9. Hsu PW, Salgado CJ, Kent K, Finnegan M, Pello M, Simons R, et al. Evaluation of porcine dermal collagen (Permacol) used in abdominal wall reconstruction. J Plast Reconstr Aesthet Surg 2009;62:1484-9. Carbonell AM, Criss CN, Cobb WS, Novitsky YW, Rosen MJ. Outcomes of synthetic mesh in contaminated ventral hernia repairs. J Am Coll Surg 2013;217:991-8. Timmermans L, de Goede B, van Dijk SM, Kleinrensink GJ, Jeekel J, Lange JF. Meta-analysis of sublay versus onlay mesh repair in incisional hernia surgery. Am J Surg 2014; 207:980-8.
Petro et al 11
54. de Vries Reilingh TS, van Geldere D, Langenhorst B, de Jong D, van der Wilt GJ, van Goor H, et al. Repair of large midline incisional hernias with polypropylene mesh: comparison of three operative techniques. Hernia 2004;8:56-9. 55. Blatnik JA, Krpata DM, Jacobs MR, Gao Y, Novitsky YW, Rosen MJ. In vivo analysis of the morphologic characteristics of synthetic mesh to resist MRSA adherence. J Gastrointest Surg 2012;16:2139-44. 56. Harrell AG, Novitsky YW, Kercher KW, Foster M, Burns JM, Kuwada TS, et al. In vitro infectability of prosthetic mesh by methicillin-resistant Staphylococcus aureus. Hernia 2006;10: 120-4. 57. Binnebosel M, Klink CD, Otto J, Conze J, Jansen PL, Anurov M, et al. Impact of mesh positioning on foreign body reaction and collagenous ingrowth in a rabbit model of open incisional hernia repair. Hernia 2010;14:71-7. 58. Orenstein SB, Qiao Y, Klueh U, Kreutzer DL, Novitsky YW. Activation of human mononuclear cells by porcine biologic meshes in vitro. Hernia 2010;14:401-7. 59. Novitsky YW, Orenstein SB, Kreutzer DL. Comparative analysis of histopathologic responses to implanted porcine biologic meshes. Hernia 2014;18:713-21. 60. Halkos ME, Puskas JD, Lattouf OM, Kilgo P, Kerendi F, Song HK, et al. Elevated preoperative hemoglobin A1c level is predictive of adverse events after coronary artery bypass surgery. J Thorac Cardiovasc Surg 2008;136:631-40. 61. Lindstrom D, Sadr Azodi O, Wladis A, Tonnesen H, Linder S, Nasell H, et al. Effects of a perioperative smoking cessation intervention on postoperative complications: a randomized trial. Ann Surg 2008;248:739-45. 62. Latham R, Lancaster AD, Covington JF, Pirolo JS, Thomas CS Jr. The association of diabetes and glucose control with surgical-site infections among cardiothoracic surgery patients. Infect Control Hosp Epidemiol 2001;22: 607-12. 63. Halkos ME, Thourani VH, Lattouf OM, Kilgo P, Guyton RA, Puskas JD. Preoperative hemoglobin a1c predicts sternal wound infection after coronary artery bypass surgery with bilateral versus single internal thoracic artery grafts. Innovations 2008;3:131-8. 64. Hikata T, Iwanami A, Hosogane N, Watanabe K, Ishii K, Nakamura M, et al. High preoperative hemoglobin A1c is a risk factor for surgical site infection after posterior thoracic and lumbar spinal instrumentation surgery. J Orthop Sci 2014;19:223-8.
Risk factors for wound morbidity after open retromuscular (sublay) hernia repair Clayton C. Petro, MD, Natasza M. Posielski, MD, Siavash Raigani, MD, Cory N. Criss, MD, Sean B. Orenstein, MD, and Yuri W. Novitsky, MD, Cleveland, OH
Background. Retrorectus repairs (RR) of abdominal wall hernias are growing in popularity, yet wound morbidity and predictors in this context have been characterized poorly. Models aimed at predicting wound morbidity typically do not control for technique and/or location of mesh. Our aim was to describe wound morbidity and risk factors specifically in the context of RR hernia repair. Our hypothesis was that the incidence of wound morbidity with mesh sublay would be less than predicted by a model that does not control for mesh position. Methods. Consecutive RR hernia repairs with at least a 90-day follow-up were identified in our prospective database and analyzed. The primary outcome measures were the incidence of surgical-site occurrence (SSO) and surgical-site infection (SSI) via modern, standardized definitions. For predictors of SSO, statistical analysis was performed with univariate analysis, v2, and logistic regression as well as multivariate regression. Results. A total of 306 patients met the inclusion criteria. Eighty-four SSOs identified in 72 (23.5%) patients included 48 (15.7%) SSIs, 14 (4.6%) instances of wound cellulitis, 12 (3.9%) skin dehiscences, 6 (2.0%) seromas, and 4 (1.3%) hematomas but no instances of mesh excision or fistula formation. Treatment entailed antibiotics alone in 30 patients, 14 bedside drainage procedures, 9 radiographically assisted drainage procedures, and 10 returns to the operating room for debridement. After multivariate analysis, diabetes (OR 2.41), hernia width >20 cm (OR 2.49), and use of biologic mesh (OR 2.93) were statistically associated with the development of a SSO (P < .05). Notably, the mere presence of contamination was not independently associated with wound morbidity (OR 1.83, P = .11). SSO and SSI rates anticipated by a recent risk prediction model were 50–80% and 17–83%, respectively, compared with our actual rates of 20–46% and 7–32%. Conclusion. Based on a large cohort of patients, we identified factors contributing to SSOs specifically for RR hernia repairs. Paradoxically, biologic mesh was an independent predictor of wound morbidity. The development of clinically important mesh complications and rates of wound morbidity less than anticipated by recent predictive models suggest that the retromuscular (sublay) mesh position may be more advantageous. (Surgery 2015;j:j-j.) From the Case Comprehensive Hernia Center, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH
DESPITE THE FREQUENCY OF INCISIONAL HERNIA REPAIR IN United States, approaches to repair vary widely.1 Although mesh reinforcement has been shown to decrease recurrence rates, positioning of the mesh relative to the musculofascial components of the abdominal wall remains debatable.2,3
THE
Accepted for publication May 12, 2015. Reprint requests: Yuri W. Novitsky, MD, Professor of Surgery, Department of Surgery, University Hospitals Case Medical Center, 11100 Euclid Avenue, LKS 5047, Cleveland, OH 44106-5047. E-mail: [email protected]. 0039-6060/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.surg.2015.05.003
Placement of mesh in the retromuscular/ retrorectus (RR) or sublay position was a technique promulgated by the French surgeons Rives and Stoppa in the 1970s.4,5 By 1991, Wantz reported the first US series using this technique.6 Since then, more than 30 reports have reinforced the low rates of recurrence (0–32%) and morbidity (2–25%) associated with RR mesh placement.7 Specifically, the technique benefits from a wide mesh overlap, ‘‘face-to-face’’ anterior/posterior muscle/fascia-mesh interfaces to promote tissue integration from vascularized tissues (as opposed to subcutaneous fat), restoration of a medial insertion point for lateral musculature, and reinforcement of the visceral sac without direct exposure SURGERY 1
ARTICLE IN PRESS 2 Petro et al
of the abdominal viscera to a foreign body.8-11 Mounting evidence supporting the positioning of mesh as a sublay has led some to consider it as the ‘‘gold standard’’ for incisional hernia repair.12,13 More recently, several modifications to the traditional Rives-Stoppa technique have been developed to provide additional lateral dissection beyond the rectus sheath. Several years ago, we presented our early experience with a novel technique for posterior component separation utilizing the transversus abdominis muscle release (TAR) to gain additional lateral retro-muscular dissection beyond the linea semilunari.14 The key features of TAR is creation of a large space for sublay mesh placement as well as the associated myofascial release with subsequent medialization of the rectus abdominis muscles, but without compromising the neurovascular integrity of the abdominal wall.14 Importantly, the aforementioned principles and benefits of the retromuscular mesh placement are maintained. Although the chief outcome measure in most reports of RR repair is recurrence, wound morbidity is uniformly important, particularly given its high cost and potential association with prosthetic infection.15-17 Unfortunately, wound morbidity has traditionally been characterized poorly in most reports of hernia repair, and reported cohorts of patients undergoing RR mesh sublay are not unique in this regard. Modern definitions of surgical-site occurrence (SSO) and surgical-site infection (SSI) as defined by the Ventral Hernia Working Group (VHWG) and Centers for Disease Control and Prevention (CDC), respectively, were only standardized recently.18 Ironically, recent attempts to characterize properly wound morbidity and its risk factors have been done in large cohorts of hernia repairs with no control for technique.19-21 One recently proposed model designed to assign SSO and SSI risks after open repair did not account for position of the mesh within the abdominal wall.20 Such a system would make a potentially erroneous assumption that RR repairs carry the same risk factors for wound morbidity as other open repairs and ‘‘might’’ predict inaccurately the expected rates of wound morbidity. Therefore, our aim was to characterize wound morbidity and its predictors specifically in the context of RR hernia repair. Furthermore, we hypothesized that the incidence of wound morbidity with mesh sublay would be less than predicted by the proposed model that does not account for the anatomic positioning of the mesh.
Surgery j 2015
METHODS A prospectively maintained, institutional review boardapproved database was used to identify all patients who underwent ventral hernia repairs between January 2009 and July 2013 at a tertiary care Hernia center. Typically, data entry was performed by the attending surgeon at the time of the operation. Postoperative events regarding wound morbidity were recorded subsequently by the attending surgeon during clinic follow-up. Inclusion criteria for the study were all patients who received RR repairs. This series included the traditional Rives-Stoppa repair alone or supplemented with a TAR with at least 90-day follow-up. Patients who underwent a concurrent panniculectomy were excluded, because they carry additional important confounding risks for wound morbidity that cannot be attributed to the hernia repair/mesh positioning alone.22 We analyzed preoperative demographics, comorbidities, operative characteristics, and postoperative outcomes of the patients. Data were supplemented with the use of electronic medical records when necessary. Demographics included patient age, sex, body mass index (BMI), number of previous abdominal operations, number of previous ventral hernia repairs, and previous history of a wound/mesh infection, as well as comorbidities, such as chronic obstructive pulmonary disease (COPD), history of smoking, active smoking (defined as smoking within 1 month of operation), and immunosuppression (defined as recent chemotherapy or taking oral antirejection medicines for solid organ transplants). Furthermore, we obtained perioperative data, such as the American Society of Anesthesiologists score, type of mesh, and defect size. The guidelines of the CDC were used to assign perioperative wounds into the 4 categories of clean, clean-contaminated, contaminated, and dirty. All patients were also stratified based on the 3-tier, modified Ventral Hernia Working Group system developed by Kanters et al.19 Grade 1 included patients with a low risk of complications and no history of wound infection. Grade 2 included patients with co-morbidities, such as obesity (BMI> 30), COPD, diabetes mellitus (DM), or smoking, as well as those patients with a history of previous wound infection. Grade 3 included patients with contaminated wound sites; Grade 3 was further stratified based on level of contamination according to the CDC categories of (A) clean-contaminated, (B) contaminated, and (C) active infection.
ARTICLE IN PRESS Surgery Volume j, Number j
Patient care and operative technique. Standardized patient care included medical optimization by our center for perioperative medicine that included but was not limited to: assessment of the cardiopulmonary risk, screening for diabetes management (hemoglobin A1C < 9), smoking cessation, universal screening for methicillinresistant Staphylococcus aureus (MRSA), and screening for sleep apnea. Cessation of smoking was required a minimum of 4 weeks before the operation and was confirmed with blood tests when necessary. Diabetics with an A1C $9% were referred to an endocrinologist and rescheduled once the diabetes was better controlled. Universal MRSA decolonization was used in all patients: every patient received intranasal mupirosin for 3 days before operation and a chlorhexidine bath the night before the operation. Those who screened positive for MRSA on a nasal swab were given a dose of preoperative vancomycin in addition to standard antimicrobial prophylaxis limited to 24 hours postoperatively. Operations all consisted of a traditional RivesStoppa RR dissection. When this type of fascial release was not sufficient for medialization of the medial aspect of the anterior rectus fascia, our previously described TAR14 (in contrast to the anterior component separation) was used to supplement the lateral dissection. The TAR allows for additional myofascial release and a wider space for mesh overlap in an avascular plane lateral to the linea semilunaris that does not disrupt the neurovascular integrity of the abdominal wall and does not require a different plane of dissection or another larger incision.14 After closure of the visceral sac, the prosthesis is placed within the retromuscular space for reinforcement before closure of the anterior rectus fascia over the prosthesis. The visceral sac is reapproximated with running 2-0 absorbable suture, the anterior fascia with running #1 slowly absorbable monofilament suture, and the skin with a running 4-0 monofilament absorbable subcuticular stitch or staples. Two closed-suction drains are placed above the retromusclar prosthesis and are maintained until their individual daily output is < 30 mL. Outcomes. The primary outcome used for analysis was the occurrence of an SSO. An SSO was defined as wound cellulitis, an SSI, seroma requiring an intervention, skin dehiscence, hematoma, or formation of enterocutaneous fistula. SSIs were further specified as superficial, deep, or organ space based on definitions from the Centers for Disease Control and Prevention. Although all SSIs required intervention, only
Petro et al 3
seromas/hematomas that required an intervention were characterized as such regardless of location. If not documented on the initial hospital stay, patients were instructed to follow-up at 2 weeks, 3 months, 6 months, and 1 year and then annually. Univariate analysis was used to identify variables associated with development of an SSO. Those variables with an association (P # .05) were entered into a multivariate analysis using binary logistic regression to identify factors that continued to demonstrate independent associations with SSO. Risks factors for SSIs were analyzed. Finally, we used our patient and operative characteristic to assign a ventral hernia risk score (VHRS) as defined by Berger et al.20 We then identified rates of SSO and SSI for the appropriate risk group and compared these rates to the rates anticipated by their scoring system. Data analysis was done using SPSS version 21 (SPSS IBM, Armonk, NY). Continuous variables were evaluated using descriptive statistics, whereas categorical variables were summarized by the use of frequency and percentages. Statistical analysis was performed using v2 and logistic regression as well as multivariate regression when appropriate. RESULTS Three hundred six patients undergoing abdominal wall reconstruction/incisional hernia repair with RR mesh placement were analyzed. Mean follow-up was 6.5 months (3–39). Patient demographics and operative characteristics are summarized in Table I. One patient developed intestinal necrosis (likely due to a thromboembolic event) with gross spillage of bowel contents on postoperative day 5 requiring reoperation, a bowel resection, and mesh explantation. This patient was excluded for analysis, because her mesh excision was not related to wound morbidity. All patients underwent a RR repair, with 62 (20%) undergoing a Rives-Stoppa RR repair alone and 244 (80%) had a TAR as well. Clean cases were present in 192 (62.7%) of the cohort, 33 (10.7%) of whom had no comorbidities (modified Ventral Hernia Working Group [mVHWG] Grade 1) and 152 (52%) of whom had medical comorbidities (mVHWG Grade 2). The remaining cases consisted of 43 (14.1%) clean-contaminated, 36 (11.8%) contaminated, and 35 (11.4%) infected fields (mVHWG Grades 3ac, respectively). The infected patients included those with active draining sinuses and enteroprosthetic and enterocutaneous fistulae. Regarding all contaminated cases (n = 114), biologic mesh was used in 70 (61%), constituting 96% (70/73) of all biologic mesh usage. Synthetic
ARTICLE IN PRESS 4 Petro et al
Surgery j 2015
Table I. Patient demographics and operative characteristics Variable Mean age Female Mean BMI Mean ASA Diabetes mellitus COPD Smoking history History of a wound infection Immunosuppression Mean no. abdominal operations Mean no. previous hernia repairs Mean hernia width, cm Mean hernia area, cm2 Rives-Stoppa/TAR Mean OR time, min Biologic/synthetic mesh Biologic mesh/mVHWG Grade 3ac Synthetic mesh/mVHWG Grade 3ac Clean mVHWG grade 1 mVHWG grade 2 Clean-contaminated, mVHWG Grade 3a Contaminated, mVHWG Grade 3b Infected, mVHWG Grade 3c*
Mean ± SD/ frequency (%) 57 ± 12 162/306 (53%) 34.4 ± 8.3 3 ± 0.4 40/306 (13.1%) 38/306 (8%) 40/36 (13.1%) 143/306 (43.8%) 18/306 (5.9%) 3.8 ± 3.1 1.8 ± 2.5 14.6 ± 5.7 329 ± 221 62/244 (20%/80%) 194 ± 80 73/233 (24%/76%) 70/114 (61.4%) 44/114 (38.6%) 192 33 159 43
(62.7%) (10.7%) (52.0%) (14.1%)
36 (11.8%) 35 (11.4%)
*Includes active infection/draining sinuses, enteroprosthetic, enterocutaneous and enteroatmospheric fistulae. ASA, American Society of Anesthesiologists; BMI, body mass index; COPD, chronic obstructive pulmonary disease; mVHWG, modified Ventral Hernia Working Group; OR, operating room; TAR, transversus abdominis muscle release.
mesh was used in the remaining 44 (39%) cases, 28 of which were clean-contaminated, 11 were contaminated, and 5 were infected. SSO and SSI. A total of 84 SSOs were identified in 72 patients, summarized in Tables II and III. Some patients had more than one SSO; the incidence of having an SSO was 24% (72/306) with 4% (13/306) of patients having multiple SSOs. SSOs consisted of 48 SSIs (48/306, 16%), 14 instances of wound cellulitis (14/306, 5%), 12 instances of skin dehiscence (12/306, 4%), 6 seromas requiring intervention (6/306, 2.0%), and 4 hematomas (4/306, 1%). There have been no instances of mesh excision or enterocuteous fistula formation to date. Instances of wound cellulitis as defined by the criteria of the CDC were treated with antibiotics
Table II. SSOs: breakdown and incidence SSOs (n = 84) SSI: 48 Wound cellulitis: 14 Seroma: 6 Skin dehiscence: 12 Hematoma: 4
Percentage of all SSOs 57% 17% 7% 15% 4%
(48/84) (14/84) (6/84) (12/84) (4/84)
Incidence of SSO 16% 5% 2% 4% 1%
(48/306) (14/306) (6/306) (12/306) (4/306)
SSI, Surgical-site infection; SSO, surgical-site occurrence.
Table III. SSOs by treatment Wound cellulitis (n = 14) Skin dehiscence (n = 12)
Seroma (n = 6) Hematoma (n = 4)
Superficial SSI (n = 22) Deep SSI (n = 26)
Antibiotics: 14 Packing: 9 Delayed primary closure: 1 Wound VAC: 1 OR debridement: 1 IR drainage: 4 I&D: 2 OR drainage: 2 IR drainage: 1 I&D: 1 Antibiotics: 15 I&D: 7 I&D: 5 IR drainage: 14 OR debridement: 7
I&D, Bedside Incision and Drainage; IR, Drainage by Interventional Radiology; OR, operating room; SSI, surgical-site infection; SSO, surgical-site occurrence; VAC, Negative Pressure Wound Therapy.
and resolved without progression in all 14 patients. For the 12 instances of skin dehiscence, wet-to-dry packing alone was used in 75% (9/12) of patients, one of whom required operative debridement of necrotic skin and one patient was treated with a vacuum-based dressing, and another underwent delayed primary closure. Finally, of the 4 hematomas, 1 was drained by interventional radiology, 1 was drained at the bedside, and 2 were drained in the operating room. Six seromas required an intervention. Four underwent IR drainage, and 2 were drained at the bedside. All cultures from the seroma samples were sterile, and the events were thus not considered as SSI. Regarding the 48 SSIs, 22 were superficial, and 26 were deep. Superficial SSIs were treated with antibiotics alone in 68% (15/22) of patients and by bedside debridement (wound opening) in the remaining 32% (7/22) of instances. Of the deep SSIs, 54% (14/26) were treated by IR drainage, 19% (5/26) by bedside drainage, and 27% (7/26) with operative debridement. All 19 IR drains were removed eventually and did not need to be replaced. All instances of skin dehiscence or superficial SSI treated with bedside
ARTICLE IN PRESS Petro et al 5
Surgery Volume j, Number j
or operative debridement followed by dressing changes healed fully within 6 months of the operation. We analyzed in detail the 12 deep SSIs that required either bedside or operative debridement with resultant mesh exposure. In a subanalysis of these patients, 6/12 contained noncrosslinked porcine dermis biologic mesh. Of those, 5 of the wounds healed completely within 6 months, 1 had a small draining sinus that resolved completely after 12 months. In the remaining 6 instances, uncoated synthetic mesh was exposed. Three patients had mid-weight polypropylene and 3 had multifilament polyester. All were treated with a combination of wet-to-dry and vacuum-based dressings. Three of these patients had chronically draining sinuses (all had multifilament polyester mesh). These patients with the chronic draining sinuses continued to have periods of transient skin healing with episodes of intermittent wound drainage controlled with a dry dressing. One other patient had a stitch abscess that required removal of a suture, whereas another was found to have a small subcutaneous piece of sponge from the vacuum dressing, and the last patient died from recurrence of a hematologic malignancy within a year of her operation. Predictors of SSO. Univariate analysis was performed to determine which factors were associated with SSO Table IV. Morbid obesity (BMI >35 kg/m2; OR 1.04, P = .012), DM (OR 3.79, P # .0001), smoking (OR 2.89, P = .0026), number of previous abdominal operations (OR 1.10, P = .019), hernia width (OR 1.08, P = .002), hernia area greater than 200 cm2 (OR 1.87, P = .05), use of biologic mesh (OR = 4.64, P # .0001), and presence of contamination (mVHWG Grade 3, OR = 3.84, P # .0001) were found to be statistically associated with SSOs. Sex, age, American Society of Anesthesiologists (ASA) Classification class, history of wound infection, COPD, immunosuppression, use of a TAR, and number of previous hernia repairs were found to have no association with the development of an SSO. Using the modified VHWG grading scale, we found 2 SSOs in 2 of 33 (6%) Grade 1 patients, 31 SSOs were found in 26 of 159 (16%) grade 2 patients, and 52 SSOs were found in 44 of 114 (39%) grade 3 patients. There were no differences between Grades 1 and 2 (P = .18), but there were between Grades 2 and 3 (P # .0001). The 2 SSOs in the Grade 1 hernia group were one SSI and one instance of wound cellulitis. In the patients with Grade 2 hernias, there were 8 superficial SSI, 7 deep SSI, 4 seromas, 6 wound dehiscences, 1 hematoma, and 5 wound cellulitis. In Grade 3
Table IV. Predictors of SSO: univariate analysis Variable Age Female Morbid obesity (BMI >35 kg/m2) ASA Diabetes mellitus COPD Smoking History of wound infection Immunosuppression No. abdominal operations No. previous hernia repairs Hernia width #10 vs >10 cm #20 vs >20 cm <10 vs 10–20 vs >20 As a continuous variable Hernia area #200 vs >200 cm2 TAR (vs Rives-Stoppa) Biologic mesh Contamination (mVHWG Grade 3)
Odds ratio (95% CI)
P value
0.98 (0.96–1.00) 0.66 (0.39–1.13) 1.04 (1.01–1.07)
.12 .13 .012
3.79 1.63 2.89 1.65 1.72 1.10 1.09
NA (2.11–6.81) (0.78–3.44) (1.44–5.78) (0.96–2.82) (0.62–4.75) (1.02–1.20) (0.99–1.20)
3.03 (1.04–8.83) 2.27 (1.24–4.13) NA 1.08 (1.03–1.13) 1.87 1.54 4.64 3.84
(0.98–3.57) (0.74–3.09) (2.55–8.46) (2.21–6.69)
.23 <.0001 .19 .003 .07 .30 .02 .08 .042 .008 .009 .002 .05 .24 <.0001 <.0001
Values in bold indicate a P value #0.05. ASA, American Society of Anesthesiologists; BMI, body mass index; COPD, chronic obstructive pulmonary disease; mVHWG, modified Ventral Hernia Working Group; NA, not available; SSO, surgical-site occurrence; TAR, transversus abdominis muscle release.
hernia patients, there were 13 superficial SSI, 19 deep SSI, 6 skin dehiscences, 3 hematomas, 1 seroma, 8 instances of wound cellulitis, and our 1 organ space infection (intraperitoneal abscess). Factors demonstrating independent associations with SSO after multivariate analysis using binary logistic regression included DM (P = .013, OR 2.41), defect width >20 (P = .012, OR 3.11), and use of biologic mesh (P = .010, OR 2.93). Alternatively, morbid obesity, smoking history, number of previous abdominal operation, and presence of contamination, while statistically significant in univariate analysis, were not statistically significant in multivariate analysis (Table V). Contaminated field and active infection were associated with a development of SSI (P < .0001) (Fig 1). Using the scoring system proposed by Berger et al, we assigned each of our 306 patients a VHRS for SSO and SSI. Regarding the VHRS for SSO, our rates of SSO were 20% (55/271) and 46% (16/35) for Groups II and III, respectively (Fig 2, A). For the VHRS for SSI, our rates of SSI were 7% (5/ 54), 10% (15/149), 21% (9/42), 32% (11/34)
ARTICLE IN PRESS 6 Petro et al
Surgery j 2015
Table V. Independent predictors of SSO after multivariate analysis Variable
Odds ratio
P value
DM Morbid obesity (BMI>35 kg/m2) Smoking history Width >20 cm No. abdominal operations Biologic mesh Contamination (mVHWG Grade 3)
2.41 (1.21–4.80) 1.01 (0.96–1.05)
.013 .545
2.14 2.49 1.03 2.93 1.83
.061 .012 .564 .010 .110
(0.97–4.73) (1.23–5.05) (0.94–1.13) (1.29–6.64) (0.87–3.82)
Values in bold indicate statistical significance. BMI, Body mass index; mVHWG, modified Ventral Hernia Working Group; SSO, surgical-site occurrence.
for Groups II-V respectively. These rates are shown against anticipated rates reported by Berger et al in Fig 2, B. DISCUSSION Retromuscular repairs with sublay mesh reinforcement continue to gain in popularity, yet risk factors for wound morbidity have not been defined. Models designed to risk-stratify patients by their potential of developing an SSO or SSI do not control for technique, and may assign an inappropriate risk to the RR repairs. In this study, we identified specific risk factors for wound morbidity in the context of open hernia repair with mesh sublay. Importantly, we demonstrated superior outcomes compared with rates of wound morbidity predicted by a recently developed, riskstratification model by Berger et al20 that does not control for mesh location. These findings support RR mesh placement in open VHR with regard to wound morbidity. Wound morbidity has been poorly characterized traditionally in reports of RR hernia repair. In 34 reports of mesh sublay from 1989 to 2013, 7 did not mention wound morbidity specifically (Table VI).5,6,8-11,14-16,23-47 In many other reports, distinctions between wound cellulitis or ‘‘wound sepsis’’ and the CDC classifications of SSI are ambiguous. Modern definitions of SSO and SSI as defined by the VHWG and CDC have only become used commonly in recent years. These classifications were either unavailable or underused, resulting in a wide range of reported rates of SSO (2.5–30%) and SSI (2.2–23.8%) within the aforementioned data. Our cohort represents a variety of comorbidities and the presence of contamination in many cases. Using strict adherence to modern definitions of SSO/SSI,
Fig 1. Surgical site infection rates in our cohort of Retromuscular repairs according to modified VHWG scale. There was a significantly higher rate of SSI in the Groups 3b and 3c when compared to Groups 1-2 and 3a.
Fig 2. Comparison of SSO (A) and SSI (B) rates in our cohort versus Ventral Hernia Risk Score (VHRS).
we found rates of 15%/8% in clean cases and 39%/36% in contaminated counterparts. This report encompasses a comprehensive experience of mesh sublay to date and provides a candid assessment of wound morbidity in this context. After multivariate analysis, the presence of DM, hernia width >20 cm, and use of biologic mesh were found to be independent risk factors for wound morbidity. The association of wound morbidity with biologic mesh but not with contamination was possibly a reflection of our tendency to use a
ARTICLE IN PRESS Petro et al 7
Surgery Volume j, Number j
Table VI. Previously reported rates of wound morbidity after RR mesh placement First author, ref
Year
N
#SSO/SSI rate (SSO%)
Mesh excision
Stoppa10 Wantz6 Rives5 Amid23 Liakakos24 McLanahan11 Schumpelick25 Luijendijk16 Martin-Duce26 Bauer9 Flament27 Ferranti28 Langer29 Petersen30 Sriussadaporn31 Kingsnorth32 Paajanen33 Novitsky34 Israelsson35 Lomanto36 Notash37 Iqbal15 Berry38 Williams39 Wheeler8 Manigrasso40 Abdollahi41 Mehrabi42 Forte43 Fei44 Maman45 Novitsky14 Str^ambu46 Schroeder47
1989 1991 1992 1994 1994 1997 1999 2000 2001 2002 2002 2003 2003 2003 2003 2004 2005 2006 2006 2006 2007 2007 2007 2008 2008 2009 2010 2010 2011 2012 2012 2012 2013 2013
368 30 258 54 102 86 146 84 152 57 693 35 155 175 9 33 84 128 228 50 86 254 47 115 90 30 312 176 246 26 89 42 45 93
16 (12%) NR 20 (8%) NR NR 16 (18%) 41/5 (28%, 3%) 3 (4%) 17 (11%) 2 (4%) 17 (3%) 5 (14%) NR 14 (8%) NR NR 13/5 (15%, 6%) 3 (2%) NR 6/3 (12%, 6%) 14/13 (16%, 15%) 33/10 (13%, 4%) 12/4 (26%, 9%)zz 27/6 (24%, 5%) 9/6 (10%, 7%) 9/5 (30%, 17%) 28/7 (9%, 2%) 8/5 (5%, 3%) 12/8 (5%, 3%) 5/1 (19%, 4%){{ 8/4 (9%, 5%) 10/10 (24%) 3 (2%) 6/0 (7%)
0 0 NR NR NR NR (4.1%) & 0 (4.6%) (3.5%)* (0.001%)y (2.8%)z NR (1.7%)x 0 (3.0%) (1.2%){ (0.01%)** NR (4%) (1.2%) (2.0%)yy 0 (3%) (5.6%)xx NR (0.003%) (1.1%) NR NR (3.4%) 0 0 0
6 7 2 1 1 3 1 1 1 2 1 5 3 5 1 2
3
*2, both ePTFE mesh. y1, polyester. z1, polypropylene. x3, all ePTFE. {1, partial mesh excision. **1, partial mesh excision–lightweight polypropylene. yy5, all mesh removed within 30 d of operation after deep SSI. zzAll had a concurrent panniculectomy. xx5, all partial excision of polyester. {{Concurrent intraperitoneal mesh. ePTFE, Expanded polytetrafluoroethylene; NR, not reported; SSI, surgical-site infection. In bold are SSO and SSI rates (as a percentage) respectively. When SSO and SSI are not distinguished, they are reported as a single value. & - 4 coated lightweight mesh and 2 heavyweight polypropylene.
biologic mesh in the most contaminated scenarios. Only 3 of the 62 cases in which biologic mesh was used were clean surgical fields; the remaining constituted 14 clean-contaminated, 18 contaminated, and 27 infected cases. Nevertheless, an SSO rate of 48% (30/62) with use of biologic mesh is low when compared with other reports, which cite wound morbidity rates as great as 87% when biologic mesh was used for ventral hernia repair.48-51
Of these 30 SSOs, 17 were SSIs, which is in line with CDC estimates of acceptable rates given the relative degree of contamination. Not surprisingly, we found that contaminated and actively infected fields were statistically more like to be associated with an SSI. Ultimately, the ongoing prospective studies comparing biologic prosthetics with synthetic mesh in contaminated surgical fields will provide guidance in these difficult situations. The
ARTICLE IN PRESS 8 Petro et al
benefits of mesh sublay and favorable characteristics of uncoated polypropylene warrant specific discussion, because these factors may remove the stigma of what many considered a surgical faux pas, ie, use of synthetic mesh in contaminated fields, the feasibility of which has been demonstrated recently by Carbonell et al.52 Retrorectus repairs may be beneficial for several reasons. First, the mesh is positioned between 2 vascularized layers of the abdominal wall, allowing for tissue ingrowth on both sides of the prosthetic. Second, there is a fascial reconstruction ventral to the mesh and as a result, there is a ‘‘protective’’ layer of autogenous fascia/muscle between superficial SSOs and the underlying prosthesis, helping to prevent mesh involvement. Next, creation of an extraperitoneal pocket, first in the retro-rectus space and supplemented with TAR when necessary, allows for lateral dissection into the retroperitoneuml; this RR space allows for wide reinforcement of the visceral sac without exposing the viscera to direct contact with the mesh as in laparoscopic counterparts. Finally, both a traditional Rives-Stoppa with or without a TAR allows for substantial myofascial medialization without raising skin flaps maintaining all the perforating vessels or compromising the neurovascular integrity of the abdominal wall.14 Furthermore, a TAR allows for all the benefits of a RivesStoppa repair to be extrapolated to patients with larger hernias requiring additional myofascial medialization. We found that adding posterior component separation via TAR to the RR approach occurred without incurring greater wound morbidity. This lateral dissection in an avascular plane is in stark contrast to wide mesh onlays that require raising large, devascularized skin flaps to create a plane anterior to the myofascial components of the abdominal wall for onlay placement of the mesh. This concern stems from multiple reports of greater wound morbidity associated with placement of mesh as an onlay versus sublay.53,54 The benefits of the onlay technique in regard to lesser operative times with less technical difficulty must be weighed against the concern for superficial SSOs more easily involving the underlying mesh. The importance of choice of prosthesis cannot be overstated. Our current practice is to use mid-weight, monofilament, macroporous polypropylene mesh because of its demonstration of superior bacterial clearance in animal studies.55,56 Notably, of 41 meshes reported previously to require excision in the RR literature, 5 were ePTFE (laminar) and 6 were polyester (multifilament)
Surgery j 2015 meshes.7-9,30 Only one partial excision and one total excision of polypropylene was mentioned specifically, whereas the remaining were not specified (Table VI). The fear of chronic prosthetic infection is underscored by Iqbal et al,15 who reported the excision of 5 prosthetics within 30 days of the initial operation due to deep SSIs; all of those meshes were heavyweight polypropylene. Again, the character of macropourous monofilament mesh in the setting of good fascial coverage appears to be able to potentially overcome what was once thought of as a predestined chronic infection if the exposed mesh was not excised. Relevant data from Binneb€ osel et al. support better fibrous capsule formation and collagen deposition when synthetic mesh was placed in the sublay position compared to onlay.57 Theoretically, these characteristics correlated with better cellular penetration and potentially superior clearance of infection. We used synthetic mesh in clean-contaminated and contaminated instances with minimal gross spillage and have previously reported acceptable outcomes.52 We attribute these favorable choices of macroporous monofilament mesh coupled with bilaminar fascial coverage with our ability to obtain full wound closure in the 12 cases of deep SSI with exposed mesh without the need for mesh excision. It is important to note that 3 of the 12 patients (all with polyester mesh) had episodes of ‘‘relapse’’ drainage we believe to be related to chronic infection of the multifilament polyester prosthetic. Our poor experience with prolonged/recurrent draining sinuses in patients with exposed multifilament polyester mesh has resulted in our shift away from polyester during open repairs. Regarding biologic meshes, non-crosslinked prosthetics have also shown a decreased foreign body reaction and attenuated cytokine expression thought to be related to prosthetic encapsulation.58,59 The choice of both type of mesh and location are intimate factors when optimizing outcomes. Although we believe that macroporous polypropylene might be advantageous in the vast majority of patients, this study was not designed to test this hypothesis and should not be relied on to guide the choice of mesh. Identifying predictors of wound morbidity can aid surgeons in patient selection and optimization. Although DM was found to correlate most strongly after multivariate analysis, smoking, and morbid obesity are notorious contributors to postoperative wound morbidity.18,19 In our current practice, patients with diabetes found to have a hemoglobin A1c >9 during their preoperative
ARTICLE IN PRESS Petro et al 9
Surgery Volume j, Number j
assessment are postponed and referred to an endocrinologist for better glucose control.60 Morbidly obese patients are referred to a medical weight-loss specialist or bariatric surgery for weight loss to a BMI of <35. Smokers are required to abstain from smoking for at least 4 weeks.61 Although obesity and smoking were not found to be independently associated with wound morbidity after multivariate analysis, we believe that controlling these comorbidities demonstrates patient ownership of their health in the perioperative period. In fact, optimization of these comorbidities may in fact have quelled their impact on wound morbidity, as demonstrated by multivariate analysis. The persistent impact of DM on outcomes suggests that our HgA1c requirement should be stricter. In fact, recent studies suggest a level less than 8% is associated with decreased wound morbidity.62-64 We have modified our preoperative strategy subsequently in patients with diabetes to delay elective open repairs until HgA1C is less than 8%. Surgeons should identify high-risk patients and optimize medical comorbidities even when contemplating a RR repair. Currently we do not perform elective, open abdominal wall reconstructions in smokers or severely morbidly obese patients. Previous attempts to characterize wound morbidity and its predictors after hernia repair have been performed with cohorts with limited or no control for technique.19-21 These models operate under the assumption that all techniques carry the same incidence and risk factors for wound complications after repair. We hypothesized that this assumption was incorrect. Our report that generated a modification of the VHWG grading scale consisted of 299 repairs: 192 RR repairs, 58 were open anterior components separation, 37 laparoscopic anterior components separation, and 12 miscellaneous procedures. We found a trend toward improved morbidity rates for RR repair that did not gain statistical significance. Our current report adds an additional 124 RR repairs, generating morbidity rates of 6%, 16%, and 39% for grades 1–3, respectively, compared with our originally reported rates of 14%, 27%, and 46% when all techniques were included.19 Furthermore, to contrast our previous report, smoking, morbid obesity, COPD, previous hernia repair, history of wound infection, and hernia size >100 cm2 were not found to be predictors of SSO with RR mesh placement. A riskstratification model proposed recently by Berger et al. was created from 888 open hernia repairs and included both primary and incisional hernias.20 Their data were used to create a weighted scoring
system for risk factors associated most strongly with SSO and SSI. Using their model, our patients were assigned to the appropriate SSO and SSI risk group. Their model would predict SSO rates of 50% and 80% for Risk Groups II and III, respectively, whereas our patients had rates of 20% and 46%. Likewise, their model predicts SSI rates of 17–83% for Risk Groups II-V, whereas our counterparts resulted in rates from 7 to 32%. Clearly, RR repairs result in less wound morbidity compared with results anticipated by other models generated by non-RR data. As an example, skin flaps were identified as a significant predictor of wound morbidity in the aforementioned classification, emphasizing why technique and morbidity should not be dissociated. Our results undermine potentially the validity of the model by Berger et al20 and should caution its widespread use. Our study is limited by its retrospective and uncontrolled design as well as limited follow-up. Also, while the primary outcome measure of this analysis was perioperative wound morbidity, recurrence rates are the ultimate measure of the adequacy and durability of hernia repair. Although our follow-up of this retrospective cohort is limited, the absence of any mesh excisions which would lead to an inevitable recurrence is promising. Interestingly, the importance of predicting and preventing wound morbidity lies in the assumption that recurrence is a function of wound morbidity. Our report demonstrates that reasonable rates of wound morbidity can be overcome without obvious long-term sequelae like mesh excision. Therefore, not only might SSO and SSI rates be less than anticipated, the effects of wound morbidity may be less devastating than experienced with other techniques. In conclusion, RR mesh sublay appears to be unique in its ability to prevent and overcome wound morbidity, defying predictions by models generated from the non-RR techniques. Overall, we believe that RR repair may be a favorable approach to minimize wound complications during open hernia repairs. REFERENCES 1. Cassar K, Munro A. Surgical treatment of incisional hernia. Br J Surg 2002;89:534-45. 2. Paul A, Korenkov M, Peters S, Kohler L, Fischer S, Troidl H. Unacceptable results of the Mayo procedure for repair of abdominal incisional hernias. Eur J Surg 1998;164:361-7. 3. Burger JW, Luijendijk RW, Hop WC, Halm JA, Verdaasdonk EG, Jeekel J. Long-term follow-up of a randomized controlled trial of suture versus mesh repair of incisional hernia. Ann Surg 2004;240:578-83; . discussion 83-5.
ARTICLE IN PRESS 10 Petro et al
4. Stoppa R, Petit J, Abourachid H, Henry X, Duclaye C, Monchaux G, et al. Original procedure of groin hernia repair: interposition without fixation of Dacron tulle prosthesis by subperitoneal median approach. [in French]. Chirurgie 1973;99:119-23. 5. Rives J, Pire JC, Flament JB, Convers G. Treatment of large eventrations (apropos of 133 cases). [in French]. Minerva Chir 1977;32:749-56. 6. Wantz GE. Incisional hernioplasty with Mersilene. Surg Gynecol Obstet 1991;172:129-37. 7. Jin J, Rosen MJ. Laparoscopic versus open ventral hernia repair. Surg Clin North Am 2008;88:1083-100; viii. 8. Wheeler AA, Matz ST, Bachman SL, Thaler K, Miedema BW. Retrorectus polyester mesh repair for midline ventral hernias. Hernia 2009;13:597-603. 9. Bauer JJ, Harris MT, Gorfine SR, Kreel I. Rives-Stoppa procedure for repair of large incisional hernias: experience with 57 patients. Hernia 2002;6:120-3. 10. Stoppa RE. The treatment of complicated groin and incisional hernias. World J Surg 1989;13:545-54. 11. McLanahan D, King LT, Weems C, Novotney M, Gibson K. Retrorectus prosthetic mesh repair of midline abdominal hernia. Am J Surg 1997;173:445-9. 12. Forte A, Zullino A, Manfredelli S, Montalto G, Covotta F, Pastore P, et al. Rives technique is the gold stardard for incisional hernioplasty. An institutional experience. Ann Ital Chir 2011;82:313-7. 13. Pauli EM, Rosen MJ. Open ventral hernia repair with component separation. Surg Clin North Am 2013;93: 1111-33. 14. Novitsky YW, Elliott HL, Orenstein SB, Rosen MJ. Transversus abdominis muscle release: a novel approach to posterior component separation during complex abdominal wall reconstruction. Am J Surg 2012;204:709-16. 15. Iqbal CW, Pham TH, Joseph A, Mai J, Thompson GB, Sarr MG. Long-term outcome of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique. World J Surg 2007;31:2398-404. 16. Luijendijk RW, Hop WC, van den Tol MP, de Lange DC, Braaksma MM, IJzermans JN, et al. A comparison of suture repair with mesh repair for incisional hernia. N Engl J Med 2000;343:392-8. 17. Urban JA. Cost analysis of surgical site infections. Surg Infect 2006;7(Suppl 1):S19-22. 18. Ventral Hernia Working Group, Breuing K, Butler CE, Ferzoco S, Franz M, Hultman CS, et al. Incisional ventral hernias: review of the literature and recommendations regarding the grading and technique of repair. Surgery 2010;148:544-58. 19. Kanters AE, Krpata DM, Blatnik JA, Novitsky YM, Rosen MJ. Modified hernia grading scale to stratify surgical site occurrence after open ventral hernia repairs. J Am Coll Surg 2012;215:787-93. 20. Berger RL, Li LT, Hicks SC, Davila JA, Kao LS, Liang MK. Development and validation of a risk-stratification score for surgical site occurrence and surgical site infection after open ventral hernia repair. J Am Coll Surg 2013;217:974-82. 21. Fischer JP, Wink JD, Nelson JA, Kovach SJ 3rd. Among 1,706 cases of abdominal wall reconstruction, what factors influence the occurrence of major operative complications? Surgery 2014;155:311-9. 22. Harth KC, Blatnik JA, Rosen MJ. Optimum repair for massive ventral hernias in the morbidly obese patient–is panniculectomy helpful? Am J Surg 2011;201:396-400; . discussion.
Surgery j 2015
23. Amid PK, Shulman AG, Lichtenstein IL. Use of Marlex mesh in the repair of recurrent incisional hernia. Br J Surg 1994;81:1827. 24. Liakakos T, Karanikas I, Panagiotidis H, Dendrinos S. Use of Marlex mesh in the repair of recurrent incisional hernia. Br J Surg 1994;81:248-9. 25. Schumpelick V, Klosterhalfen B, Muller M, Klinge U. [Minimized polypropylene mesh for preperitoneal net plasty (PNP) of incisional hernias]. Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen 1999;70:422-30. 26. Martin-Duce A, Noguerales F, Villeta R, Hernandez P, Lozano O, Keller J, et al. Modifications to Rives technique for midline incisional hernia repair. Hernia 2001;5:70-2. 27. Flament JB, Palot JP, Lubrano D, Levy-Chazal N, Conce JP, Marcus C. [Retromuscular prosthetic repair: experience from France]. Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen. 2002;73:1053-8. 28. Ferranti F, Triveri P, Mancini P, Di Paola M. The treatment of large midline incisional hernias using a retromuscular prosthetic mesh (Stoppa-Rives technique). Chir Ital 2003; 55:129-36. 29. Langer C, Liersch T, Kley C, Flosman M, Suss M, Siemer A, et al. Twenty-five years of experience in incisional hernia surgery. A comparative retrospective study of 432 incisional hernia repairs. [in German]. Chirurgia 2003;74:638-45. 30. Petersen S, Henke G, Zimmermann L, Aumann G, Hellmich G, Ludwig K. Ventral rectus fascia closure on top of mesh hernia repair in the sublay technique. Plast Reconstr Surg 2004;114:1754-60. 31. Sriussadaporn S, Pak-Art R, Bunjongsat S. Immediate closure of the open abdomen with bilateral bipedicle anterior abdominal skin flaps and subsequent retrorectus prosthetic mesh repair of the late giant ventral hernias. J Trauma 2003;54:1083-9. 32. Kingsnorth AN, Sivarajasingham N, Wong S, Butler M. Open mesh repair of incisional hernias with significant loss of domain. Ann R Coll Surg Engl 2004;86:363-6. 33. Paajanen H, Laine H. Operative treatment of massive ventral hernia using polypropylene mesh: a challenge for surgeon and anesthesiologist. Hernia 2005;9:62-7. 34. Novitsky YW, Cobb WS, Kercher KW, Matthews BD, Sing RF, Heniford BT. Laparoscopic ventral hernia repair in obese patients: a new standard of care. Arch Surg 2006;141:57-61. 35. Israelsson LA, Smedberg S, Montgomery A, Nordin P, Spangen L. Incisional hernia repair in Sweden 2002. Hernia 2006;10:258-61. 36. Lomanto D, Iyer SG, Shabbir A, Cheah WK. Laparoscopic versus open ventral hernia mesh repair: a prospective study. Surg Endosc 2006;20:1030-5. 37. Yaghoobi Notash A, Yaghoobi Notash A Jr, Seied Farshi J, Ahmadi Amoli H, Salimi J, Mamarabadi M. Outcomes of the Rives-Stoppa technique in incisional hernia repair: ten years of experience. Hernia 2007;11:25-9. 38. Berry MF, Paisley S, Low DW, Rosato EF. Repair of large complex recurrent incisional hernias with retromuscular mesh and panniculectomy. Am J Surg 2007;194:199-204. 39. Williams RF, Martin DF, Mulrooney MT, Voeller GR. Intraperitoneal modification of the Rives-Stoppa repair for large incisional hernias. Hernia 2008;12:141-5. 40. Manigrasso A, Candioli S, Arcieri S, Palazzini G, Filippini A. Incisional hernia prosthetic surgery: a prospective study comparing laparoscopic and open techniques. [in Italian]. G Chir 2009;30:201-14. 41. Abdollahi A, Maddah GH, Mehrabi BM, Jangjoo A, Forghani MN, Sharbaf N. Prosthetic incisional
ARTICLE IN PRESS Surgery Volume j, Number j
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
hernioplasty: clinical experience with 354 cases. Hernia 2010;14:569-73. Mehrabi M, Jangjoo A, Tavoosi H, Kahrom M, Kahrom H. Long-term outcome of Rives-Stoppa technique in complex ventral incisional hernia repair. World J Surg 2010;34: 1696-701. Forte A, Zullino A, Manfredelli S, Montalto G, Bezzi M. Incisional hernia surgery: report on 283 cases. Eur Rev Med Pharmacol Sci 2011;15:644-8. Fei Y. Compound repair of intraperitoneal onlay mesh associated with the sublay technique for giant lower ventral hernia. Ann Plast Surg 2012;69:192-6. Maman D, Greenwald D, Kreniske J, Royston A, Powers S, Bauer J. Modified Rives-Stoppa technique for repair of complex incisional hernias in 59 patients. Ann Plast Surg 2012;68:190-3. Str^ambu V, Radu P, Bratucu M, Garofil D, Iorga C, Iorga R, et al. Rives technique, a gold standard for incisional hernias---our experience. Chirurgia 2013;108:46-50. Schroeder AD, Debus ES, Schroeder M, Reinpold WM. Laparoscopic transperitoneal sublay mesh repair: a new technique for the cure of ventral and incisional hernias. Surg Endosc 2013;27:648-54. Helton WS, Fisichella PM, Berger R, Horgan S, Espat NJ, Abcarian H. Short-term outcomes with small intestinal submucosa for ventral abdominal hernia. Arch Surg 2005; 140:549-60; . discussion 60-2. Bellows CF, Shadduck PP, Helton WS, Fitzgibbons RJ. The design of an industry-sponsored randomized controlled trial to compare synthetic mesh versus biologic mesh for inguinal hernia repair. Hernia 2011;15:325-32. Harth KC, Rosen MJ. Major complications associated with xenograft biologic mesh implantation in abdominal wall reconstruction. Surg Innov 2009;16:324-9. Hsu PW, Salgado CJ, Kent K, Finnegan M, Pello M, Simons R, et al. Evaluation of porcine dermal collagen (Permacol) used in abdominal wall reconstruction. J Plast Reconstr Aesthet Surg 2009;62:1484-9. Carbonell AM, Criss CN, Cobb WS, Novitsky YW, Rosen MJ. Outcomes of synthetic mesh in contaminated ventral hernia repairs. J Am Coll Surg 2013;217:991-8. Timmermans L, de Goede B, van Dijk SM, Kleinrensink GJ, Jeekel J, Lange JF. Meta-analysis of sublay versus onlay mesh repair in incisional hernia surgery. Am J Surg 2014; 207:980-8.
Petro et al 11
54. de Vries Reilingh TS, van Geldere D, Langenhorst B, de Jong D, van der Wilt GJ, van Goor H, et al. Repair of large midline incisional hernias with polypropylene mesh: comparison of three operative techniques. Hernia 2004;8:56-9. 55. Blatnik JA, Krpata DM, Jacobs MR, Gao Y, Novitsky YW, Rosen MJ. In vivo analysis of the morphologic characteristics of synthetic mesh to resist MRSA adherence. J Gastrointest Surg 2012;16:2139-44. 56. Harrell AG, Novitsky YW, Kercher KW, Foster M, Burns JM, Kuwada TS, et al. In vitro infectability of prosthetic mesh by methicillin-resistant Staphylococcus aureus. Hernia 2006;10: 120-4. 57. Binnebosel M, Klink CD, Otto J, Conze J, Jansen PL, Anurov M, et al. Impact of mesh positioning on foreign body reaction and collagenous ingrowth in a rabbit model of open incisional hernia repair. Hernia 2010;14:71-7. 58. Orenstein SB, Qiao Y, Klueh U, Kreutzer DL, Novitsky YW. Activation of human mononuclear cells by porcine biologic meshes in vitro. Hernia 2010;14:401-7. 59. Novitsky YW, Orenstein SB, Kreutzer DL. Comparative analysis of histopathologic responses to implanted porcine biologic meshes. Hernia 2014;18:713-21. 60. Halkos ME, Puskas JD, Lattouf OM, Kilgo P, Kerendi F, Song HK, et al. Elevated preoperative hemoglobin A1c level is predictive of adverse events after coronary artery bypass surgery. J Thorac Cardiovasc Surg 2008;136:631-40. 61. Lindstrom D, Sadr Azodi O, Wladis A, Tonnesen H, Linder S, Nasell H, et al. Effects of a perioperative smoking cessation intervention on postoperative complications: a randomized trial. Ann Surg 2008;248:739-45. 62. Latham R, Lancaster AD, Covington JF, Pirolo JS, Thomas CS Jr. The association of diabetes and glucose control with surgical-site infections among cardiothoracic surgery patients. Infect Control Hosp Epidemiol 2001;22: 607-12. 63. Halkos ME, Thourani VH, Lattouf OM, Kilgo P, Guyton RA, Puskas JD. Preoperative hemoglobin a1c predicts sternal wound infection after coronary artery bypass surgery with bilateral versus single internal thoracic artery grafts. Innovations 2008;3:131-8. 64. Hikata T, Iwanami A, Hosogane N, Watanabe K, Ishii K, Nakamura M, et al. High preoperative hemoglobin A1c is a risk factor for surgical site infection after posterior thoracic and lumbar spinal instrumentation surgery. J Orthop Sci 2014;19:223-8.