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Surgical site occurrences, not body mass index, increase the long-term risk of ventral hernia recurrence
Surgery xxx (2020) 1e7
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Surgical site occurrences, not body mass index, increase the long-term risk of ventral hernia recurrence Joshua S. Jolissaint, MDa,b,*, Bryan V. Dieffenbach, MDa, Thomas C. Tsai, MD, MPHa, Luise I. Pernar, MDc, Brent T. Shoji, MDa, Stanley W. Ashley, MD, FACSa,d, Ali Tavakkoli, MD, FACSa,d a
Department of Surgery, Brigham and Women’s Hospital, Boston, MA Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY Department of Surgery, Boston Medical Center, MA d Laboratory for Metabolic and Surgical Research, Brigham and Women’s Hospital, Boston, MA b c
a r t i c l e i n f o
a b s t r a c t
Article history: Accepted 2 January 2020 Available online xxx
Background: Recurrence rates after ventral hernia repair vary widely and evidence about risk factors for recurrence are conflicting. There is little evidence for risk factors for long-term recurrence. Methods: Patients who underwent ventral hernia repair at our institution and were captured in the American College of Surgeons-National Surgical Quality Improvement Program database between 2002 and 2015 were included. We reviewed all demographic, procedural, and hernia-specific data. Results: Six hundred and thirty patients were included for analysis with a median follow-up of 4.9 years (inter-quartile range, 2e7.3 years). By univariate analysis, index hernia repairs were more likely to recur if defect size was 4 cm (P ¼ .019), no mesh was used (P ¼ .026), or if the repair was for a recurrent hernia (P ¼ .001). Five-year cumulative incidence of recurrence and reoperation was 24.3% and 16.0%, respectively. Patients with a perioperative surgical site occurrence, which included superficial, deep-incisional, and organ space surgical site infections as well as wound disruption, had a 5-year cumulative incidence of recurrence of 54.9% compared with 22.6% for those without surgical site occurrence. By multivariable analysis, non-primary hernia repair (hazard ratio 1.7, 95% confidence interval 1.2e2.4, P ¼ .005) and any postoperative surgical site occurrence (hazard ratio 1.9, 95% confidence interval 1.1e3.6, P ¼ .02) were the only risk factors predictive of recurrence. Patient body mass index had no independent effect on recurrence. Conclusion: 1 in 4 patients undergoing an open ventral hernia repair will have a recurrence after 5 years, and this risk is doubled among patients who experience any perioperative surgical site occurrence. After controlling for patient comorbidities, including body mass index, hernia size, and mesh position, the most significant risk factor for recurrence after ventral hernia repair was a non-primary hernia and surgical site occurrence. © 2020 Elsevier Inc. All rights reserved.
Introduction Ventral hernia repairs (VHR) are among the most common operations performed by general surgeons each year.1 While laparoscopic repair is becoming increasingly utilized, over 70% of ventral hernias in the United States are still repaired using open Joshua S. Jolissaint and Bryan V. Dieffenbach are co-first authors and contributed equally to this work. Presented at the podium at the American College of Surgeons Clinical Congress, October 21 to 25, 2018, Boston, MA. * Reprint requests: Joshua S. Jolissaint, MD, Department of Surgery, 75 Francis Street, Boston, Massachusetts, 02215. E-mail address: [email protected] (J.S. Jolissaint). https://doi.org/10.1016/j.surg.2020.01.001 0039-6060/© 2020 Elsevier Inc. All rights reserved.
techniques.2,3 Reported recurrence rates after VHR in the literature vary widely and range from 2.7% to 20% for primary ventral hernia (umbilical and epigastric) to 32% to 37% for incisional hernia repairs, depending on the series in question.4e10 These rates are heavily influenced by follow-up time and how hernia recurrence is defined, with claims databases often using reoperation as a surrogate for recurrence, which may significantly underestimate incidence.7 Risk factors for recurrence, which include both patient-related and perioperative factors, have all been extensively studied, but these studies have often been conflicting. As examples, both body mass index (BMI) and smoking are traditionally regarded as risk factors for recurrence; however, many investigations have found no association.11e17 Furthermore,
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although the use of mesh is associated with a decreased risk of recurrence, data is inconclusive regarding whether the location of mesh placement actually impacts long-term recurrence risk.15,16,18 The rate of perioperative complications varies between 3% to 20% after open VHR and has been associated with multiple factors including case urgency, operative time, patient age, comorbidities, and body mass index (BMI).19e24 Generally, these may include pneumonia, urinary tract infection, and hernia-specific complications. VHRs are at risk for surgical site occurrences (SSOs), which include surgical site infections (SSIs), seromas, hematomas, and mesh infections.25 Prior studies evaluating the relationship between SSO and recurrence have been limited by small cohort size and relatively short follow-up intervals.5,12,26e28 In this study, we merged a large clinical hernia database containing detailed perioperative patient factors from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP), with individual operative report review and longterm follow-up with individual chart reviews including imaging, to investigate the risk factors for and rates of long-term clinical recurrence and reoperation after open VHR. Based on prior studies, we established that elevated BMI was related to the development of surgical complications, and in this study, we hypothesized that the development of surgical complications was the major mediating factor contributing to long-term hernia recurrence.
or >10 cm).32 According to this schema, primary repair refers to a sutured repair without mesh; sublay is defined as mesh placement beneath the fascia in the retromuscular, preperitoneal, or intraperitoneal position; onlay describes mesh placement above the fascia; and inlay or bridging repair describes mesh placed within the hernial defect with circumferential fixation and no fascial apposition. SSOs were defined as any of the following: superficial SSIs, deep-incisional SSIs, organ-space infection, or postoperative wound disruption, which approximates the definition of SSO from the Ventral Hernia Working Group.33 Notably, NSQIP is unable to capture wound ischemia without dehiscence, stitch abscesses, or non-infected seroma/hematomas. Wound infections were classified based on the ACS-NSQIP guidelines, which use the Centers for Disease Control and Prevention definitions.34 Wound disruption indicates partial or complete separation of the layers of the surgical wound. The primary outcome of this study was ventral hernia recurrence, which was defined as either reoperation for recurrence or recurrence identified on a surgeon’s physical examination or after review of cross-sectional imaging within the follow-up period. The secondary outcome was reoperation for ventral hernia recurrence.
Methods
Univariate comparisons were conducted with t tests for continuous variables and with Fisher exact test for categorical variables. We evaluated the unadjusted 5-year cumulative incidence (CumI) for ventral hernia recurrence and reoperation overall and by patient, hernia, and surgical factors that were either identified in the univariate analyses or of interest clinically. Cox proportional hazards regression models were used to identify independent predictors of recurrence adjusting for patient variables including age, sex, race/ethnicity, BMI, preoperative NSQIP comorbidities, hernia variables including type of hernia, defect size, and repair of a previously recurrent hernia and surgical factors including surgeon of record, use of mesh and mesh position, emergency status, and postoperative SSO. By utilizing a surgeon fixed effect, we effectively compared the relationship of SSO on recurrence and reoperation within a surgeon’s specific practice with the overall effect averaged across surgeons at our institution. A value of P < .05 was considered statistically significant. All analyses were performed with Stata statistical software (Stata Version 12; StataCorp, College Station, TX). This study was approved by the Institutional Review Board before data collection (Partners IRB# 2015P001582).
This was a retrospective analysis of patients who underwent open VHR at our institution between 2002 and 2015 and were also captured in the institutional NSQIP database. The ACS-NSQIP database includes over 250 variables pertaining to patient demographics, comorbidities, operative variables, and postoperative complications. Further details of the NSQIP database are described in previous reports.29e31 Our institutional NSQIP database was queried using Current Procedural Terminology codes 49560 and 49561 (open repair of initial incisional or ventral hernia, reducible [e60], incarcerated or strangulated [e61]) and 49565 and 49566 (open repair of recurrent incisional or ventral hernia, reducible [e65], incarcerated or strangulated [e66]). Parastomal hernias were excluded. A detailed chart review, including independent review of all available cross-sectional abdominal imaging, was performed for all patients with a follow-up time of at least 3 months. A total of 630 patients were included in the final cohort for analysis. Within the NSQIP Participant Use Data File, we reviewed all patient demographic data, comorbidities, operative variables, and postoperative factors. Variables were sub-categorized into patient factors, hernia factors, and surgical factors. Patient factors included age, sex, race/ethnicity, preoperative BMI (categorical instead of continuous variables were employed owing to a nonlinear association with recurrence: <18.5, 18.5e24.9, 25e34.9, and 35 kg/m2), smoking, and alcohol use. Operative notes were abstracted by 2 of the study authors (B.D., J.J.) to identify hernia and perioperative variables including type of hernia, fascial defect size, case urgency (urgent or nonurgent), wound classification (clean, clean-contaminated, contaminated, or dirty/infected), and mesh position (see below). Hernia was size was missing from the medical record in 51.4% of the observations, and we used a mean imputation approach with a dummy variable for the missing observations in our modeling to account for potential bias in this approach. Hernias were categorized according to the European Hernia Society classification system as either incisional midline, incisional lateral, or primary midline with defect size defined as maximum diameter of the fascial defect by intraoperative measurement or preoperative imaging (categorized as <4 cm, 4e10 cm
Statistical analysis
Results Demographics A total of 630 patients were included in the analysis. Median follow-up time was 4.9 years (interquartile range [IQR], 2e7.3 years). With respect to BMI, 5 patients (0.8%) were underweight (<18.5 kg/m2), 110 (17.5%) were of normal weight (18.5e24.9 kg/ m2), 333 (52.9%) were overweight or classified as obesity grade I (25e34.9 kg/m2), and 182 (28.9%) were classified as obesity grade II or higher (BMI 35 kg/m2). Seventy-three patients (11.6%) had diabetes and 94 (14.9%) were smokers. Incisional midline was the most common type of hernia (469/630, 74.4%), followed by incisional lateral (81/630, 12.9%), and primary midline (61/630, 9.7%). Mesh repair predominated over primary/sutured repair with sublay repair performed in 360 patients (57.1%), onlay repair in 151 (24.0%), and inlay repair in 49 (7.8%). Sixty-two patients received a
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3
Table I Patient demographics and repair details for patients undergoing open ventral hernia repair Characteristics Patient factors Female sex [n, (%)] Age (y) (mean ± SD) Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic/Latino Other BMI (kg/m2) <18.5 18.5e24.9 25e34.9 35 Comorbidities Diabetes Smoker Hernia factors Type of hernia Primary midline Incisional midline Incisional lateral Defect size (cm) <4 cm 4 cm to <10 cm 10 cm Recurrent repair Surgical factors Type of repair Suture repair Mesh repair Mesh position Primary repair/no mesh Onlay Sublay Inlay Urgent/emergency status Wound classification Clean Clean-contaminated Contaminated Infected/dirty Complications* Any postoperative SSO Superficial incisional SSI Deep incisional SSI Organ-space SSI Wound disruption
Recurrence (n ¼ 178)
No recurrence (n ¼ 452)
P
111 (65.49) 53.05 ± 13.49
296 (62.36) 56.23 ± 13.85
.55 .0093 .034
137 (76.97) 18 (10.11) 3 (1.69) 20 (11.24)
337 (74.56) 57 (12.61) 0 (0) 58 (12.83)
2 (1.12) 28 (15.73) 87 (48.88) 61 (34.27)
3 (0.66) 82 (18.14) 246 (54.42) 121 (26.77)
19 (10.67) 31 (17.42)
54 (11.95) 63 (13.94)
21 (11.8) 132 (74.6) 25 (14.04)
59 (13.05) 337 (74.56) 56 (12.39)
30 (16.85) 134 (75.28) 14 (7.87) 65 (36.52)
122 (26.99) 290 (64.16) 40 (8.85) 104 (23.01)
25 (14.04) 153 (85.96)
37 (8.19) 415 (91.81)
25 (14.04) 51 (28.65) 87 (48.88) 15 (8.43) 9 (5.06)
37 (8.19) 108 (23.89) 273 (60.40) 34 (7.52) 22 (4.87)
166 (93.26) 5 (2.81) 3 (1.69) 4 (2.25)
441 (97.57) 5 (1.11) 4 (0.88) 2 (0.44)
17 (9.55) 13 (7.30) 2 (1.12) 2 (1.12) 1 (0.56)
13 (2.88) 9 (1.99) 1 (0.22) 3 (0.66) 2 (0.44)
.26
.65 .27 .81
.019
.001 .026
.034
.92 .053
<.001 .001 .14 .56 .85
Percentages are column percentages. * Numbers sum to greater than 100% owing to potential for multiple events for a given individual. SD, standard deviation.
primary repair (9.8%). Mean hernia defect size was 5.23 ± 3.52 cm in maximal dimension. The index hernia repair at our institution was for a recurrent hernia in 169 patients (26.8%). Urgent cases accounted for 31 operations (4.9%) and operative wound classification was reported as clean in 607 cases (96.3%). Of our cohort, 178 patients developed a recurrent hernia and 102 ultimately underwent a repair. Recurrence was diagnosed by physical examination in 95 patients (53.4%) and by imaging in 83 patients (46.6%). Patients who ultimately developed a hernia recurrence were younger (53.05 vs 56.23 years, P ¼ .009) and more likely to be white (P ¼ .034) (Table I). Index hernia repairs were more likely to recur if defect size was 4 cm (P ¼ .019), employed a suture-based repair (P ¼ .026), or if the repair was for a recurrent hernia (P ¼ .001). Patients who did not recur were more likely to have a sublay mesh placed at the time of repair compared with onlay, inlay, or suture-based (P ¼ .034). Patients who experienced any type of postoperative SSO, including superficial, deep, and organ-space SSI and wound disruption, were also more likely to recur (P ¼ .001).
Hernia recurrence and reoperation rates The unadjusted 5-year CumI of hernia recurrence after index hernia repair was 24.3% for recurrence and 16.0%, for reoperation. Among patients with recurrence, median time to diagnosis of recurrence was 2.26 years (IQR 1.0e5.0) and median time to reoperation for hernia recurrence was 1.9 years (IQR 1.0e3.9) years. The unadjusted 5-year CumI of hernia recurrence and reoperation overall and by selected factors of clinical interest are displayed in Table II. The unadjusted 5-year CumI of recurrence was 33.5% for recurrent repairs, compared with 21.1% for initial repairs (risk difference, þ12.4%) and 26.9% and 23.8% in smokers and nonsmokers, respectively (risk difference, þ3.1%). When stratified by BMI class, the unadjusted 5-year CumI of recurrence for normal BMI (18.5e24.9 kg/m2) was 19.6%, BMI 25e34.9 kg/m2 was 24.5% (risk difference, þ4.9%), and BMI 35 kg/m2 was 26.4% (risk difference, þ1.9%). When evaluated by mesh position, the unadjusted 5-year CumI for hernia recurrence after primary suture repair was 37.0%, inlay repair was 28.1% (risk difference, e8.9),
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J.S. Jolissaint et al. / Surgery xxx (2020) 1e7 Table II Unadjusted 5-year cumulative incidence of recurrence after index VHR. Overall and by selected preoperative factors Hernia recurrence
Overall Recurrent repair Yes No Smoker Yes No BMI (kg/m2)* 18.5e24.9 25e34.9 35 Mesh position Primary repair/no mesh Onlay Sublay Inlay Postoperative SSO Yes No Overall
Hernia reoperation
5-year CI (%)
Risk difference
5-year CI (%)
Risk difference
24.3
-
16.0
-
33.5 21.1
þ12.4
26.5 12.3
þ14.2
26.9 23.8
þ3.1
17.3 15.7
þ1.6
19.6 24.5 26.4
þ4.9 þ6.8
13.7 15.6 18.1
þ2.5 þ4.4
37.0 24.6 21.5 28.1
e12.4 e15.5 e8.9
28.1 18.5 12.6 18.0
e9.6 e15.5 e10.1
54.9 22.6
þ32.3
44.9 14.4
þ30.5
CI, cumulative incidence. * BMI of <18.5 kg/m2 excluded given small cohort size.
onlay repair was 24.6% (risk difference, e12.4%), and sublay repair was the lowest at 21.5% (risk difference, e15.5%). In patients who were diagnosed with a 30-day postoperative SSO, the 5-year CumI of recurrence was 54.9% compared with 22.6% for those without an SSO (risk difference, þ32.3%). When reviewing recurrences over time, patients who developed a 30-day perioperative SSO had an increased risk for hernia recurrence up to 5-years postoperatively (Fig 1). Risk factors associated with hernia recurrence and reoperation A Cox regression analysis was performed controlling for patient demographics (age, race, and sex), patient comorbidities (including BMI, smoking, and diabetes), wound complications, wound classification, urgency of the operation, hernia type, hernia size, repair type, and attending surgeon of record (Table III). After controlling for these variables, undergoing a recurrent repair (hazard ratio [HR] 1.7, 95% CI 1.2e2.4, P ¼ .005) and having any postoperative SSO (HR 1.9, 95% CI 1.1e3.6, P ¼ .02) were the only 2 factors that remained predictive of recurrence postoperatively. Sex, age, race/ethnicity, BMI, diabetes, smoking, hernia type, defect size, mesh position, and case urgency were not independently associated with hernia recurrence. We performed a sensitivity analysis by separating superficial SSI and controlling for deep-incisional and organ-space SSIs and dehiscence, wherein superficial SSI alone was not significant for recurrence (HR 1.96, 95% CI 0.97e3.9, P ¼ .061) (Supplementary Table I). We performed a second sensitivity analysis in which wound dehiscence was removed as a covariate, thus isolating only infectious complications, with no change in the model compared with Table III. The unadjusted 5-year CumI of reoperation was lower than that of recurrence (16% vs 24.3%) suggesting that not all recurrences were ultimately repaired (Table II). As with recurrence, both recurrent repairs (HR 2.2, 95% CI 1.4e3.5, P ¼ .001) and any postoperative SSO (HR 2.1, 95% CI 0.3e4.3, P ¼ .04) were also independently associated with reoperation for hernia recurrence. Sex, age, race/ethnicity, BMI, diabetes, smoking, hernia type, defect size, mesh position, and case urgency were similarly not independently associated with hernia reoperation
Discussion In this study, we demonstrated that after controlling for patient and perioperative factors, SSO represents the most significant independent risk factor for hernia recurrence. By univariate analysis, multiple factors were shown to contribute to hernia recurrence after operation, including large defect size, mesh position, and recurrent (as opposed to a primary) repair. BMI, smoking, and diabetes were not significantly associated with recurrence; however, there was a stepwise increase in 5-year cumulative incidence with increasing BMI status (although BMI was not statistically significant on univariable or multivariable analysis). By multivariable analysis, after controlling for multiple factors including BMI, postoperative SSOs and recurrent repairs were the only significant factors predictive of both recurrence and reoperation. Notably, the 5-year cumulative incidence of recurrence in patients who experienced any SSO was more than double those without an SSO. This risk of recurrence extended up to 5-years postoperatively. Reported rates of hernia recurrence are highly variable in the surgical literature and are largely dependent on how recurrence is defined and the length of postoperative follow-up. In a cohort recruited from the Danish Ventral Hernia Database, Helgstrand et al showed that using reoperation for hernia recurrence as an outcome to estimate overall recurrence, as is done in many claims database studies, significantly underestimates the true clinical recurrence rate by up to 5-fold.7 Among randomized controlled trials that prospectively followed patients after open VHR, reported recurrence rates range from 0% at 2 months to 9.7% at study conclusion, although loss to follow-up and relatively short follow-up duration limit the generalizability of these data.22,35e38 In comparison, several retrospective studies have shown long-term recurrence risk can exceed 30%.4,7,16 In this study, we present an overall recurrence risk of 28.3% after VHR, a figure in line with prior studies of similar size and follow-up, suggesting that our results are representative of the actual hernia recurrence burden and supports the applicability of these findings to the general VHR population. Interestingly, neither BMI, smoking, nor diabetes were associated with hernia recurrence by univariable or multivariable analysis. Within the literature, the associations of these risk factors with
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5
Fig. 1. Unadjusted 5-year cumulative risk of recurrence comparing patients with and without a postoperative surgical site occurrence
Table III Multivariable Cox regression analysis of factors associated with ventral hernia recurrence and reoperation Variables
Patient factors Male (referent female) Age White (referent non-white) BMI (kg/m2) <18.5 18.5e24.9 25e34.9 35 Comorbidities (referent no) Diabetes Smoker Hernia factors Type of hernia Primary midline Incisional midline Incisional lateral Defect Size (cm) Recurrent repair (referent initial) Surgical factors Mesh position Primary repair/no mesh Onlay Sublay Inlay Emergency (referent no) Complications Any postoperative SSO
Recurrence
Reoperation
Hazard ratio (95% CI)
P
Hazard ratio (95% CI)
P
0.75 (0.53e1.1) 1.0 (0.98e1.0) 0.9 (0.8e1.1)
.11 .37 .42
0.77 (0.5e1.2) 1.0 (1.0e1.0) 0.8 (0.6e1.0)
.24 .24 .10
1.4 (0.3e6.5) Ref 1.1 (0.6e1.7) 1.6 (0.9e2.8)
.65 .84 .09
1.3 (0.2e11) Ref 1.1 (0.6e2.1) 1.7 (0.8e3.6)
.80 .85 .15
0.9 (0.5e1.5) 1.3 (0.9e1.8)
.73 .18
0.5 (0.2e1.2) 1.7 (1.0e2.9)
.12 .067
Ref 1.5 (0.9e2.5) 1.6 (0.8e3.2) 1.3 (0.8e2.2) 1.7 (1.2e2.4)
.17 .17 .29 .005
Ref 1.3 (0.6e2.9) 2.0 (0.8e4.9) 1.3 (0.8e2.2) 2.2 (1.4e3.5)
.50 .15 .29 .001
Ref 1.2 (0.5e3.0) 0.9 (0.4e2.1) 0.7 (0.3e1.9) 0.7 (0.3e1.6)
.72 .76 .48 .43
Ref 1.0 (0.3e3) 0.6 (0.2e1.8) 0.4 (0.1e1.6) 0.98 (0.4e2.5)
.94 .37 .18 .98
1.9 (1.1e3.6)
.02
2.1 (0.3e4.3)
.04
CI, confidence interval.
recurrence are often conflicting. An early study by Sauerland et al reported a relative risk of incisional hernia recurrence of 1.51 for patients with a BMI of >30 kg/m2 with an increased risk based both on a meta-analysis from published reports between 1988 to 2003 and when analyzing data from a previously published clinical trial.11 However, in a 2010 report by Hawn et al analyzing the longterm outcomes for incisional hernia repair, there was no association with BMI on recurrence at a median follow-up of 73.4 months.16
More recent reports have suggested that BMI may in fact contribute to recurrence risk for ventral and umbilical hernia repairs; however, the relationship with absolute weight and increasing BMI category is unclear.12,13 There is also uncertainty as to how obesity could influence recurrenceewhether through impaired wound healing, abdominal wall tension, or technical difficulty at the index operation.11 However, there is good evidence that BMI itself is associated with an
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increased risk of SSO and overall complications.21,39,40 These data suggest that BMI may be an indirect contributor to recurrence by increasing the overall risk of surgical site infections, seromas, and other wound complications. In our study, we demonstrate that SSOs are the most important contributors to recurrence with a HR of 1.9 (95% CI 1.1e3.6, P ¼ .02). In a recent retrospective study, Owei et al found that 10.7% of patients undergoing open VHR have at least one 30-day postoperative complication and 6.9% suffer a surgical site complication, specifically superficial or deep incisional SSI, organ space SSI, or wound disruptions.24 In prospective studies, early postoperative complications were much more common and identified in up to 26% of patients after open VHR.22,35e38 A retrospective study of open retromuscular repair at a single institution showed that postoperative SSI was the only predictor of long-term hernia recurrence, and a separate retrospective cohort study showed a higher incidence of early SSOs in those patients with long-term hernia recurrence.26,28 These data support our finding that patients with 30-day postoperative SSO are at >2-fold risk for long-term ventral hernia recurrence relative to those without perioperative SSO. This effect is driven almost entirely by infectious complications, specifically superficial SSIs; however, with only 3 wound separation events in the full cohort, it is difficult to comment on their contribution when generalized to a larger scale. Our data suggest that ventral hernias should be considered as a chronic disease process. The risk of ventral hernia recurrence can extend up to 5 years postoperatively, which is in contrast to prior studies reporting that the majority of recurrences occur within 2 years postoperatively.9 Further, the vast majority of SSOs in our cohort were superficial SSIs suggesting that relatively minor complications can drastically affect long-term morbidity. Thus, although the linear association between BMI, smoking, and diabetes remains undetermined, focused efforts at smoking cessation and preoperative weight loss may indirectly increase the durability of repairs by decreasing the rate of SSO.41,42 This knowledge supports the use of techniques such as laparoscopic surgery, when appropriate and clinically indicated, given the lower rate of infectious complications with this approach, in addition to SSI reduction bundles and caution when operating in contaminated fields.43e47 However, this study also highlights the complexity of chronic ventral hernias and lends support to the goal of creating comprehensive hernia centers that may provide specialized and tailored care for these patients.48,49 In our institutional practice, we aim to minimize the development of SSO based on the evidence that SSOs are related to long-term recurrence. We optimize patients preoperatively by encouraging smoking cessation and glycemic control among diabetics to minimize SSOs. Our present study suggests that the relationship between BMI and recurrence is likely mediated through the development of SSOs, and we, therefore, selectively refer patients with a BMI >40 kg/m2 for bariatric surgery and/or medical weight loss before definitive VHR. There are several limitations to this study that warrant consideration. First, the retrospective nature of this study limited the granularity of the data that could be abstracted. Granularity is also limited when utilizing the NSQIP database, which does not include some components of the Ventral Hernia Working Group definition for SSO, such as stitch abscess or non-infected hematoma or seroma. Second, these findings are not based on randomized patient selection; thus, selection bias for open VHR approach cannot be controlled. Although we controlled for the operating surgeon, practice patterns for open VHR have evolved over the study period, which may affect the generalizability of results over time. In conclusion, overall, we found that almost 1 in 4 patients undergoing an open VHR will have a recurrence after 5 years. One in 6 patients undergoing an open VHR will undergo repair for a
recurrence. After controlling for patient comorbidities, hernia size, and mesh position, the most significant risk factor for recurrence after VHR was a non-primary hernia and SSO. Taken together, our findings suggest that ventral hernias should be considered a complex and chronic disease process with long-term morbidity. Efforts aimed at reducing rates of hernia recurrence should focus on providing specialized care to these complex patients with an aim to concurrently reduce the risk of SSIs and wound disruptions. Funding/Support This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Joshua Jolissaint receives support from the Weill Cornell Medical College Clinical and Translational Science Center funded by NIH/NCATS UL1TR002384. Conflict of interest/Disclosure Ali Tavakkoli, MD, served as a consultant for Medtronic. Thomas Tsai, MD, MPH, serves on the scientific advisory board for Seamless Mobile Health and served as a consultant for Sigilon Therapeutics. Supplementary materials Supplementary material associated with this article can be found, in the online version, at https://doi.org/10.1016/j.surg.2020. 01.001. References 1. Poulose BK, Shelton J, Phillips S, et al. Epidemiology and cost of ventral hernia repair: making the case for hernia research. Hernia. 2012;16:179e183. 2. Mason RJ, Moazzez A, Sohn HJ, Berne TV, Katkhouda N. Laparoscopic versus open anterior abdominal wall hernia repair: 30-day morbidity and mortality using the ACS-NSQIP database. Ann Surg. 2011;254:641e652. 3. Aher C, Kubasiak JC, Daly SC, et al. The utilization of laparoscopy in ventral hernia repair: an update of outcomes analysis using ACS-NSQIP data. Surg Endosc. 2015;29:1099e1104. 4. Burger JW, Luijendijk RW, Hop WC, et al. Long-term follow-up of a randomized controlled trial of suture versus mesh repair of incisional hernia. Ann Surg. 2004;240:578e585. 5. Luijendijk RW, Hop WC, van den Tol MP, et al. A comparison of suture repair with mesh repair for incisional hernia. N Engl J Med. 2000;343:392e398. 6. den Hartog D, Dur AH, Tuinebreijer WE, Kreis RW. Open surgical procedures for incisional hernias. Cochrane Database Syst Rev. 2008;(3):CD006438. 7. Helgstrand F, Rosenberg J, Kehlet H, Strandfelt P, Bisgaard T. Reoperation versus clinical recurrence rate after ventral hernia repair. Ann Surg. 2012;256: 955e958. €genur I, Rosenberg J. Long-term recurrence and 8. Andersen LP, Klein M, Go complication rates after incisional hernia repair with the open onlay technique. BMC Surg. 2009;9:6. 9. Singhal V, Szeto P, VanderMeer TJ, Cagir B. Ventral hernia repair: Outcomes change with long-term follow-up. JSLS. 2012;16:373e379. 10. Nguyen MT, Berger RL, Hicks SC, et al. Comparison of outcomes of synthetic mesh vs suture repair of elective primary ventral herniorrhaphy : a systematic review and meta-analysis. JAMA Surg. 2014;149:415e421. 11. Sauerland S, Korenkov M, Kleinen T, Arndt M, Paul A. Obesity is a risk factor for recurrence after incisional hernia repair. Hernia. 2004;8:42e46. 12. Stey AM, Russell MM, Sugar CA, et al. Extending the value of the National Surgical Quality Improvement Program claims dataset to study long-term outcomes: rate of repeat ventral hernia repair. Surgery. 2015;157:1157e1165. 13. Shankar DA, Itani KMF, O’Brien WJ, Sanchez VM. Factors associated with longterm outcomes of umbilical hernia repair. JAMA Surg. 2017;152:461e466. J, Torregrosa A, Jime nez-Rosello n R, García P, Bonafe S, Iserte J. 14. Bueno-Lledo Predictors of hernia recurrence after Rives-Stoppa repair in the treatment of incisional hernias: a retrospective cohort. Surg Endosc. 2019;33:2934e2940. 15. Holihan JL, Alawadi Z, Martindale RG, et al. Adverse events after ventral hernia repair: the vicious cycle of complications. J Am Coll Surg. 2015;221:478e485. 16. Hawn MT, Snyder CW, Graham LA, Gray SH, Finan KR, Vick CC. Long-term follow-up of technical outcomes for incisional hernia repair. J Am Coll Surg. 2010;210:655e657. 17. Hesselink VJ, Luijendijk RW, de Wilt JH, Heide R, Jeekel J. An evaluation of risk factors in incisional hernia recurrence. Surg Gynecol Obstet. 1993;176:228e234.
J.S. Jolissaint et al. / Surgery xxx (2020) 1e7 18. Kokotovic D, Bisgaard T, Helgstrand F. Long-term recurrence and complications associated with elective incisional hernia repair. JAMA. 2016;316:1575e1582. 19. Qin C, Souza J, Aggarwal A, Kim JY. Insulin dependence as an independent predictor of perioperative morbidity after ventral hernia repair: a National Surgical Quality Improvement Program analysis of 45,759 patients. Am J Surg. 2016;211:11e17. 20. Qin C, Hackett NJ, Kim JY. Assessing the safety of outpatient ventral hernia repair: a NSQIP analysis of 7666 patients. Hernia. 2015;19:919e926. 21. Pernar LIM, Pernar CH, Dieffenbach BV, Brooks DC, Smink DS, Tavakkoli A. What is the BMI threshold for open ventral hernia repair? Surg Endosc. 2017;31:1311e1317. 22. Eker HH, Hansson BM, Buunen M, et al. Laparoscopic vs open incisional hernia repair a randomized clinical trial. JAMA Surg. 2013;148:259e263. 23. Kroese LF, Gillion JF, Jeekel J, Lange JF, Kleinrensink GJ, and the Hernia-Club Members. Identification of risk factors for 30-day postoperative complications in patients undergoing primary ventral hernia repair: a prospective cohort study of 2,374 patients. Surgery. 2018;163:1160e1164. 24. Owei L, Swendiman RA, Kelz RR, Dempsey DT, Dumon KR. Impact of body mass index on open ventral hernia repair: a retrospective review. Surgery. 2017;162: 1320e1329. 25. Bleier JIS, Resnick AS. Complications of incisional hernia repair. Semin Colon Rectal Surg. 2009;20:125e130. 26. Cobb WS, Warren JA, Ewing JA, Burnikel A, Merchant M, Carbonell AM. Open retromuscular mesh repair of complex incisional hernia: predictors of wound events and recurrence. J Am Coll Surg. 2015;220:606e613. 27. Juvany M, Hoyuela C, Trias M, Carvajal F, Ardid J, Martrat A. Impact of surgical site infections on elective incisional hernia surgery: a prospective study. Surg Infect (Larchmt). 2018;19:339e344. 28. Warren JA, McGrath SP, Hale AL, Ewing JA. Carbonell AM 2nd, Cobb WS 4th. Patterns of recurrence and mechanisms of failure after open ventral hernia repair with mesh. Am Surg. 2017;83:1275e1282. 29. Fink AS, Campbell DA, Mentzer RM Jr, et al. The National Surgical Quality Improvement Program in non-veterans administration hospitals: initial demonstration of feasibility. Ann Surg. 2002;236:344e353; discussion 353e354. 30. Birkmeyer JD, Shahian DM, Dimick JB, et al. Blueprint for a New American College of Surgeons: National Surgical Quality Improvement Program. J Am Coll Surg. 2008;207:777e782. 31. Hall BL, Hamilton BH, Richards K, Bilimoria KY, Cohen ME, Ko CY. Does surgical quality improve in the American College of Surgeons National Surgical Quality Improvement Program: an evaluation of all participating hospitals. Ann Surg. 2009;250:363e376. 32. Muysoms FE, Miserez M, Berrevoet F, et al. Classification of primary and incisional abdominal wall hernias. Hernia. 2009;13:407e414. 33. Haskins I, Horne C, Krpata D, et al. A call for standardization of wound events reporting following ventral hernia repair. Hernia. 2018;22:729e736. 34. Centers for Disease Control and Prevention (CDC). Surgical site infection (SSI) event; 2017. https://www.cdc.gov/infectioncontrol/guidelines/ssi/index.html. Accessed October 20, 2019.
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35. Rogmark P, Petersson U, Bringman S, et al. Short-term outcomes for open and laparoscopic midline incisional hernia repair: a randomized multicenter controlled trial: the ProLOVE (prospective randomized trial on open versus laparoscopic operation of ventral eventrations) trial. Ann Surg. 2013;258: 37e45. 36. Itani KMF, Hur K, Kim LT, et al. and the Veterans Affairs Ventral Incisional Hernia Investigators. Comparison of laparoscopic and open repair with mesh for the treatment of ventral incisional hernia: a randomized trial. Arch Surg. 2010;145:322e328; discussion 328. J, Peiro S, et al. Open randomized clinical trial of laparoscopic 37. Asencio F, Aguilo versus open incisional hernia repair. Surg Endosc. 2009;23:1441e1448. 38. Pring CM, Tran V, O’Rourke N, Martin IJ. Laparoscopic versus open ventral hernia repair: a randomized controlled trial. ANZ J Surg. 2008;78: 903e906. 39. Giordano SA, Garvey PB, Baumann DP, Liu J, Butler CE. The impact of body mass index on abdominal wall reconstruction outcomes: a comparative study. Plast Reconstr Surg. 2017;139:1234e1244. €wenmark T, Dahlstrand U, Gunnarsson U. Risk fac40. Lindmark M, Strigård K, Lo tors for surgical complications in ventral hernia repair. World J Surg. 2018;42: 3528e3536. 41. Chandeze MM, Moszkowicz D, Beauchet A, Vychnevskaia K, Peschaud F, Bouillot JL. Ventral hernia surgery in morbidly obese patients, immediate or after bariatric surgery preparation: results of a case-matched study. Surg Obes Relat Dis. 2019;15:83e88. 42. Saxony J, Cowling L, Catchpole L, Walker N. Evaluation of a smoking cessation service in elective surgery. J Surg Res. 2017;212:33e41. 43. Al Chalabi H, Larkin J, Mehigan B, McCormick P. A systematic review of laparoscopic versus open abdominal incisional hernia repair, with meta-analysis of randomized controlled trials. Int J Surg. 2015;20:65e74. 44. Kaafarani HMA, Kaufman D, Reda D, Itani KM. Predictors of surgical site infection in laparoscopic and open ventral incisional herniorrhaphy. J Surg Res. 2010;163:229e234. 45. Xourafas D, Lipsitz SR, Negro P, Ashley SW, Tavakkolizadeh A. Impact of mesh use on morbidity following ventral hernia repair with a simultaneous bowel resection. Arch Surg. 2010;145:739e744. 46. Hoang SC, Klipfel AA, Roth LA, Vrees M, Schechter S, Shah N. Colon and rectal surgery surgical site infection reduction bundle: to improve is to change. Am J Surg. 2019;217:40e45. 47. Cima R, Dankbar E, Lovely J, et al, and the Colorectal Surgical Site Infection Reduction Team. Colorectal surgery surgical site infection reduction program: a national surgical quality improvement programedriven multidisciplinary single-institution experience. J Am Coll Surg. 2013;216:23e33. 48. Raigani S, De Silva GS, Criss CN, Novitsky YW, Rosen MJ. The impact of developing a comprehensive hernia center on the referral patterns and complexity of hernia care. Hernia. 2014;18:625e630. €ckerling F, Sheen AJ, Berrevoet F, et al. Accreditation and certification re49. Ko quirements for hernia centers and surgeons: the ACCESS project. Hernia. 2019;23:185e203.
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Surgical site occurrences, not body mass index, increase the long-term risk of ventral hernia recurrence Joshua S. Jolissaint, MDa,b,*, Bryan V. Dieffenbach, MDa, Thomas C. Tsai, MD, MPHa, Luise I. Pernar, MDc, Brent T. Shoji, MDa, Stanley W. Ashley, MD, FACSa,d, Ali Tavakkoli, MD, FACSa,d a
Department of Surgery, Brigham and Women’s Hospital, Boston, MA Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY Department of Surgery, Boston Medical Center, MA d Laboratory for Metabolic and Surgical Research, Brigham and Women’s Hospital, Boston, MA b c
a r t i c l e i n f o
a b s t r a c t
Article history: Accepted 2 January 2020 Available online xxx
Background: Recurrence rates after ventral hernia repair vary widely and evidence about risk factors for recurrence are conflicting. There is little evidence for risk factors for long-term recurrence. Methods: Patients who underwent ventral hernia repair at our institution and were captured in the American College of Surgeons-National Surgical Quality Improvement Program database between 2002 and 2015 were included. We reviewed all demographic, procedural, and hernia-specific data. Results: Six hundred and thirty patients were included for analysis with a median follow-up of 4.9 years (inter-quartile range, 2e7.3 years). By univariate analysis, index hernia repairs were more likely to recur if defect size was 4 cm (P ¼ .019), no mesh was used (P ¼ .026), or if the repair was for a recurrent hernia (P ¼ .001). Five-year cumulative incidence of recurrence and reoperation was 24.3% and 16.0%, respectively. Patients with a perioperative surgical site occurrence, which included superficial, deep-incisional, and organ space surgical site infections as well as wound disruption, had a 5-year cumulative incidence of recurrence of 54.9% compared with 22.6% for those without surgical site occurrence. By multivariable analysis, non-primary hernia repair (hazard ratio 1.7, 95% confidence interval 1.2e2.4, P ¼ .005) and any postoperative surgical site occurrence (hazard ratio 1.9, 95% confidence interval 1.1e3.6, P ¼ .02) were the only risk factors predictive of recurrence. Patient body mass index had no independent effect on recurrence. Conclusion: 1 in 4 patients undergoing an open ventral hernia repair will have a recurrence after 5 years, and this risk is doubled among patients who experience any perioperative surgical site occurrence. After controlling for patient comorbidities, including body mass index, hernia size, and mesh position, the most significant risk factor for recurrence after ventral hernia repair was a non-primary hernia and surgical site occurrence. © 2020 Elsevier Inc. All rights reserved.
Introduction Ventral hernia repairs (VHR) are among the most common operations performed by general surgeons each year.1 While laparoscopic repair is becoming increasingly utilized, over 70% of ventral hernias in the United States are still repaired using open Joshua S. Jolissaint and Bryan V. Dieffenbach are co-first authors and contributed equally to this work. Presented at the podium at the American College of Surgeons Clinical Congress, October 21 to 25, 2018, Boston, MA. * Reprint requests: Joshua S. Jolissaint, MD, Department of Surgery, 75 Francis Street, Boston, Massachusetts, 02215. E-mail address: [email protected] (J.S. Jolissaint). https://doi.org/10.1016/j.surg.2020.01.001 0039-6060/© 2020 Elsevier Inc. All rights reserved.
techniques.2,3 Reported recurrence rates after VHR in the literature vary widely and range from 2.7% to 20% for primary ventral hernia (umbilical and epigastric) to 32% to 37% for incisional hernia repairs, depending on the series in question.4e10 These rates are heavily influenced by follow-up time and how hernia recurrence is defined, with claims databases often using reoperation as a surrogate for recurrence, which may significantly underestimate incidence.7 Risk factors for recurrence, which include both patient-related and perioperative factors, have all been extensively studied, but these studies have often been conflicting. As examples, both body mass index (BMI) and smoking are traditionally regarded as risk factors for recurrence; however, many investigations have found no association.11e17 Furthermore,
2
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although the use of mesh is associated with a decreased risk of recurrence, data is inconclusive regarding whether the location of mesh placement actually impacts long-term recurrence risk.15,16,18 The rate of perioperative complications varies between 3% to 20% after open VHR and has been associated with multiple factors including case urgency, operative time, patient age, comorbidities, and body mass index (BMI).19e24 Generally, these may include pneumonia, urinary tract infection, and hernia-specific complications. VHRs are at risk for surgical site occurrences (SSOs), which include surgical site infections (SSIs), seromas, hematomas, and mesh infections.25 Prior studies evaluating the relationship between SSO and recurrence have been limited by small cohort size and relatively short follow-up intervals.5,12,26e28 In this study, we merged a large clinical hernia database containing detailed perioperative patient factors from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP), with individual operative report review and longterm follow-up with individual chart reviews including imaging, to investigate the risk factors for and rates of long-term clinical recurrence and reoperation after open VHR. Based on prior studies, we established that elevated BMI was related to the development of surgical complications, and in this study, we hypothesized that the development of surgical complications was the major mediating factor contributing to long-term hernia recurrence.
or >10 cm).32 According to this schema, primary repair refers to a sutured repair without mesh; sublay is defined as mesh placement beneath the fascia in the retromuscular, preperitoneal, or intraperitoneal position; onlay describes mesh placement above the fascia; and inlay or bridging repair describes mesh placed within the hernial defect with circumferential fixation and no fascial apposition. SSOs were defined as any of the following: superficial SSIs, deep-incisional SSIs, organ-space infection, or postoperative wound disruption, which approximates the definition of SSO from the Ventral Hernia Working Group.33 Notably, NSQIP is unable to capture wound ischemia without dehiscence, stitch abscesses, or non-infected seroma/hematomas. Wound infections were classified based on the ACS-NSQIP guidelines, which use the Centers for Disease Control and Prevention definitions.34 Wound disruption indicates partial or complete separation of the layers of the surgical wound. The primary outcome of this study was ventral hernia recurrence, which was defined as either reoperation for recurrence or recurrence identified on a surgeon’s physical examination or after review of cross-sectional imaging within the follow-up period. The secondary outcome was reoperation for ventral hernia recurrence.
Methods
Univariate comparisons were conducted with t tests for continuous variables and with Fisher exact test for categorical variables. We evaluated the unadjusted 5-year cumulative incidence (CumI) for ventral hernia recurrence and reoperation overall and by patient, hernia, and surgical factors that were either identified in the univariate analyses or of interest clinically. Cox proportional hazards regression models were used to identify independent predictors of recurrence adjusting for patient variables including age, sex, race/ethnicity, BMI, preoperative NSQIP comorbidities, hernia variables including type of hernia, defect size, and repair of a previously recurrent hernia and surgical factors including surgeon of record, use of mesh and mesh position, emergency status, and postoperative SSO. By utilizing a surgeon fixed effect, we effectively compared the relationship of SSO on recurrence and reoperation within a surgeon’s specific practice with the overall effect averaged across surgeons at our institution. A value of P < .05 was considered statistically significant. All analyses were performed with Stata statistical software (Stata Version 12; StataCorp, College Station, TX). This study was approved by the Institutional Review Board before data collection (Partners IRB# 2015P001582).
This was a retrospective analysis of patients who underwent open VHR at our institution between 2002 and 2015 and were also captured in the institutional NSQIP database. The ACS-NSQIP database includes over 250 variables pertaining to patient demographics, comorbidities, operative variables, and postoperative complications. Further details of the NSQIP database are described in previous reports.29e31 Our institutional NSQIP database was queried using Current Procedural Terminology codes 49560 and 49561 (open repair of initial incisional or ventral hernia, reducible [e60], incarcerated or strangulated [e61]) and 49565 and 49566 (open repair of recurrent incisional or ventral hernia, reducible [e65], incarcerated or strangulated [e66]). Parastomal hernias were excluded. A detailed chart review, including independent review of all available cross-sectional abdominal imaging, was performed for all patients with a follow-up time of at least 3 months. A total of 630 patients were included in the final cohort for analysis. Within the NSQIP Participant Use Data File, we reviewed all patient demographic data, comorbidities, operative variables, and postoperative factors. Variables were sub-categorized into patient factors, hernia factors, and surgical factors. Patient factors included age, sex, race/ethnicity, preoperative BMI (categorical instead of continuous variables were employed owing to a nonlinear association with recurrence: <18.5, 18.5e24.9, 25e34.9, and 35 kg/m2), smoking, and alcohol use. Operative notes were abstracted by 2 of the study authors (B.D., J.J.) to identify hernia and perioperative variables including type of hernia, fascial defect size, case urgency (urgent or nonurgent), wound classification (clean, clean-contaminated, contaminated, or dirty/infected), and mesh position (see below). Hernia was size was missing from the medical record in 51.4% of the observations, and we used a mean imputation approach with a dummy variable for the missing observations in our modeling to account for potential bias in this approach. Hernias were categorized according to the European Hernia Society classification system as either incisional midline, incisional lateral, or primary midline with defect size defined as maximum diameter of the fascial defect by intraoperative measurement or preoperative imaging (categorized as <4 cm, 4e10 cm
Statistical analysis
Results Demographics A total of 630 patients were included in the analysis. Median follow-up time was 4.9 years (interquartile range [IQR], 2e7.3 years). With respect to BMI, 5 patients (0.8%) were underweight (<18.5 kg/m2), 110 (17.5%) were of normal weight (18.5e24.9 kg/ m2), 333 (52.9%) were overweight or classified as obesity grade I (25e34.9 kg/m2), and 182 (28.9%) were classified as obesity grade II or higher (BMI 35 kg/m2). Seventy-three patients (11.6%) had diabetes and 94 (14.9%) were smokers. Incisional midline was the most common type of hernia (469/630, 74.4%), followed by incisional lateral (81/630, 12.9%), and primary midline (61/630, 9.7%). Mesh repair predominated over primary/sutured repair with sublay repair performed in 360 patients (57.1%), onlay repair in 151 (24.0%), and inlay repair in 49 (7.8%). Sixty-two patients received a
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3
Table I Patient demographics and repair details for patients undergoing open ventral hernia repair Characteristics Patient factors Female sex [n, (%)] Age (y) (mean ± SD) Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic/Latino Other BMI (kg/m2) <18.5 18.5e24.9 25e34.9 35 Comorbidities Diabetes Smoker Hernia factors Type of hernia Primary midline Incisional midline Incisional lateral Defect size (cm) <4 cm 4 cm to <10 cm 10 cm Recurrent repair Surgical factors Type of repair Suture repair Mesh repair Mesh position Primary repair/no mesh Onlay Sublay Inlay Urgent/emergency status Wound classification Clean Clean-contaminated Contaminated Infected/dirty Complications* Any postoperative SSO Superficial incisional SSI Deep incisional SSI Organ-space SSI Wound disruption
Recurrence (n ¼ 178)
No recurrence (n ¼ 452)
P
111 (65.49) 53.05 ± 13.49
296 (62.36) 56.23 ± 13.85
.55 .0093 .034
137 (76.97) 18 (10.11) 3 (1.69) 20 (11.24)
337 (74.56) 57 (12.61) 0 (0) 58 (12.83)
2 (1.12) 28 (15.73) 87 (48.88) 61 (34.27)
3 (0.66) 82 (18.14) 246 (54.42) 121 (26.77)
19 (10.67) 31 (17.42)
54 (11.95) 63 (13.94)
21 (11.8) 132 (74.6) 25 (14.04)
59 (13.05) 337 (74.56) 56 (12.39)
30 (16.85) 134 (75.28) 14 (7.87) 65 (36.52)
122 (26.99) 290 (64.16) 40 (8.85) 104 (23.01)
25 (14.04) 153 (85.96)
37 (8.19) 415 (91.81)
25 (14.04) 51 (28.65) 87 (48.88) 15 (8.43) 9 (5.06)
37 (8.19) 108 (23.89) 273 (60.40) 34 (7.52) 22 (4.87)
166 (93.26) 5 (2.81) 3 (1.69) 4 (2.25)
441 (97.57) 5 (1.11) 4 (0.88) 2 (0.44)
17 (9.55) 13 (7.30) 2 (1.12) 2 (1.12) 1 (0.56)
13 (2.88) 9 (1.99) 1 (0.22) 3 (0.66) 2 (0.44)
.26
.65 .27 .81
.019
.001 .026
.034
.92 .053
<.001 .001 .14 .56 .85
Percentages are column percentages. * Numbers sum to greater than 100% owing to potential for multiple events for a given individual. SD, standard deviation.
primary repair (9.8%). Mean hernia defect size was 5.23 ± 3.52 cm in maximal dimension. The index hernia repair at our institution was for a recurrent hernia in 169 patients (26.8%). Urgent cases accounted for 31 operations (4.9%) and operative wound classification was reported as clean in 607 cases (96.3%). Of our cohort, 178 patients developed a recurrent hernia and 102 ultimately underwent a repair. Recurrence was diagnosed by physical examination in 95 patients (53.4%) and by imaging in 83 patients (46.6%). Patients who ultimately developed a hernia recurrence were younger (53.05 vs 56.23 years, P ¼ .009) and more likely to be white (P ¼ .034) (Table I). Index hernia repairs were more likely to recur if defect size was 4 cm (P ¼ .019), employed a suture-based repair (P ¼ .026), or if the repair was for a recurrent hernia (P ¼ .001). Patients who did not recur were more likely to have a sublay mesh placed at the time of repair compared with onlay, inlay, or suture-based (P ¼ .034). Patients who experienced any type of postoperative SSO, including superficial, deep, and organ-space SSI and wound disruption, were also more likely to recur (P ¼ .001).
Hernia recurrence and reoperation rates The unadjusted 5-year CumI of hernia recurrence after index hernia repair was 24.3% for recurrence and 16.0%, for reoperation. Among patients with recurrence, median time to diagnosis of recurrence was 2.26 years (IQR 1.0e5.0) and median time to reoperation for hernia recurrence was 1.9 years (IQR 1.0e3.9) years. The unadjusted 5-year CumI of hernia recurrence and reoperation overall and by selected factors of clinical interest are displayed in Table II. The unadjusted 5-year CumI of recurrence was 33.5% for recurrent repairs, compared with 21.1% for initial repairs (risk difference, þ12.4%) and 26.9% and 23.8% in smokers and nonsmokers, respectively (risk difference, þ3.1%). When stratified by BMI class, the unadjusted 5-year CumI of recurrence for normal BMI (18.5e24.9 kg/m2) was 19.6%, BMI 25e34.9 kg/m2 was 24.5% (risk difference, þ4.9%), and BMI 35 kg/m2 was 26.4% (risk difference, þ1.9%). When evaluated by mesh position, the unadjusted 5-year CumI for hernia recurrence after primary suture repair was 37.0%, inlay repair was 28.1% (risk difference, e8.9),
4
J.S. Jolissaint et al. / Surgery xxx (2020) 1e7 Table II Unadjusted 5-year cumulative incidence of recurrence after index VHR. Overall and by selected preoperative factors Hernia recurrence
Overall Recurrent repair Yes No Smoker Yes No BMI (kg/m2)* 18.5e24.9 25e34.9 35 Mesh position Primary repair/no mesh Onlay Sublay Inlay Postoperative SSO Yes No Overall
Hernia reoperation
5-year CI (%)
Risk difference
5-year CI (%)
Risk difference
24.3
-
16.0
-
33.5 21.1
þ12.4
26.5 12.3
þ14.2
26.9 23.8
þ3.1
17.3 15.7
þ1.6
19.6 24.5 26.4
þ4.9 þ6.8
13.7 15.6 18.1
þ2.5 þ4.4
37.0 24.6 21.5 28.1
e12.4 e15.5 e8.9
28.1 18.5 12.6 18.0
e9.6 e15.5 e10.1
54.9 22.6
þ32.3
44.9 14.4
þ30.5
CI, cumulative incidence. * BMI of <18.5 kg/m2 excluded given small cohort size.
onlay repair was 24.6% (risk difference, e12.4%), and sublay repair was the lowest at 21.5% (risk difference, e15.5%). In patients who were diagnosed with a 30-day postoperative SSO, the 5-year CumI of recurrence was 54.9% compared with 22.6% for those without an SSO (risk difference, þ32.3%). When reviewing recurrences over time, patients who developed a 30-day perioperative SSO had an increased risk for hernia recurrence up to 5-years postoperatively (Fig 1). Risk factors associated with hernia recurrence and reoperation A Cox regression analysis was performed controlling for patient demographics (age, race, and sex), patient comorbidities (including BMI, smoking, and diabetes), wound complications, wound classification, urgency of the operation, hernia type, hernia size, repair type, and attending surgeon of record (Table III). After controlling for these variables, undergoing a recurrent repair (hazard ratio [HR] 1.7, 95% CI 1.2e2.4, P ¼ .005) and having any postoperative SSO (HR 1.9, 95% CI 1.1e3.6, P ¼ .02) were the only 2 factors that remained predictive of recurrence postoperatively. Sex, age, race/ethnicity, BMI, diabetes, smoking, hernia type, defect size, mesh position, and case urgency were not independently associated with hernia recurrence. We performed a sensitivity analysis by separating superficial SSI and controlling for deep-incisional and organ-space SSIs and dehiscence, wherein superficial SSI alone was not significant for recurrence (HR 1.96, 95% CI 0.97e3.9, P ¼ .061) (Supplementary Table I). We performed a second sensitivity analysis in which wound dehiscence was removed as a covariate, thus isolating only infectious complications, with no change in the model compared with Table III. The unadjusted 5-year CumI of reoperation was lower than that of recurrence (16% vs 24.3%) suggesting that not all recurrences were ultimately repaired (Table II). As with recurrence, both recurrent repairs (HR 2.2, 95% CI 1.4e3.5, P ¼ .001) and any postoperative SSO (HR 2.1, 95% CI 0.3e4.3, P ¼ .04) were also independently associated with reoperation for hernia recurrence. Sex, age, race/ethnicity, BMI, diabetes, smoking, hernia type, defect size, mesh position, and case urgency were similarly not independently associated with hernia reoperation
Discussion In this study, we demonstrated that after controlling for patient and perioperative factors, SSO represents the most significant independent risk factor for hernia recurrence. By univariate analysis, multiple factors were shown to contribute to hernia recurrence after operation, including large defect size, mesh position, and recurrent (as opposed to a primary) repair. BMI, smoking, and diabetes were not significantly associated with recurrence; however, there was a stepwise increase in 5-year cumulative incidence with increasing BMI status (although BMI was not statistically significant on univariable or multivariable analysis). By multivariable analysis, after controlling for multiple factors including BMI, postoperative SSOs and recurrent repairs were the only significant factors predictive of both recurrence and reoperation. Notably, the 5-year cumulative incidence of recurrence in patients who experienced any SSO was more than double those without an SSO. This risk of recurrence extended up to 5-years postoperatively. Reported rates of hernia recurrence are highly variable in the surgical literature and are largely dependent on how recurrence is defined and the length of postoperative follow-up. In a cohort recruited from the Danish Ventral Hernia Database, Helgstrand et al showed that using reoperation for hernia recurrence as an outcome to estimate overall recurrence, as is done in many claims database studies, significantly underestimates the true clinical recurrence rate by up to 5-fold.7 Among randomized controlled trials that prospectively followed patients after open VHR, reported recurrence rates range from 0% at 2 months to 9.7% at study conclusion, although loss to follow-up and relatively short follow-up duration limit the generalizability of these data.22,35e38 In comparison, several retrospective studies have shown long-term recurrence risk can exceed 30%.4,7,16 In this study, we present an overall recurrence risk of 28.3% after VHR, a figure in line with prior studies of similar size and follow-up, suggesting that our results are representative of the actual hernia recurrence burden and supports the applicability of these findings to the general VHR population. Interestingly, neither BMI, smoking, nor diabetes were associated with hernia recurrence by univariable or multivariable analysis. Within the literature, the associations of these risk factors with
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Fig. 1. Unadjusted 5-year cumulative risk of recurrence comparing patients with and without a postoperative surgical site occurrence
Table III Multivariable Cox regression analysis of factors associated with ventral hernia recurrence and reoperation Variables
Patient factors Male (referent female) Age White (referent non-white) BMI (kg/m2) <18.5 18.5e24.9 25e34.9 35 Comorbidities (referent no) Diabetes Smoker Hernia factors Type of hernia Primary midline Incisional midline Incisional lateral Defect Size (cm) Recurrent repair (referent initial) Surgical factors Mesh position Primary repair/no mesh Onlay Sublay Inlay Emergency (referent no) Complications Any postoperative SSO
Recurrence
Reoperation
Hazard ratio (95% CI)
P
Hazard ratio (95% CI)
P
0.75 (0.53e1.1) 1.0 (0.98e1.0) 0.9 (0.8e1.1)
.11 .37 .42
0.77 (0.5e1.2) 1.0 (1.0e1.0) 0.8 (0.6e1.0)
.24 .24 .10
1.4 (0.3e6.5) Ref 1.1 (0.6e1.7) 1.6 (0.9e2.8)
.65 .84 .09
1.3 (0.2e11) Ref 1.1 (0.6e2.1) 1.7 (0.8e3.6)
.80 .85 .15
0.9 (0.5e1.5) 1.3 (0.9e1.8)
.73 .18
0.5 (0.2e1.2) 1.7 (1.0e2.9)
.12 .067
Ref 1.5 (0.9e2.5) 1.6 (0.8e3.2) 1.3 (0.8e2.2) 1.7 (1.2e2.4)
.17 .17 .29 .005
Ref 1.3 (0.6e2.9) 2.0 (0.8e4.9) 1.3 (0.8e2.2) 2.2 (1.4e3.5)
.50 .15 .29 .001
Ref 1.2 (0.5e3.0) 0.9 (0.4e2.1) 0.7 (0.3e1.9) 0.7 (0.3e1.6)
.72 .76 .48 .43
Ref 1.0 (0.3e3) 0.6 (0.2e1.8) 0.4 (0.1e1.6) 0.98 (0.4e2.5)
.94 .37 .18 .98
1.9 (1.1e3.6)
.02
2.1 (0.3e4.3)
.04
CI, confidence interval.
recurrence are often conflicting. An early study by Sauerland et al reported a relative risk of incisional hernia recurrence of 1.51 for patients with a BMI of >30 kg/m2 with an increased risk based both on a meta-analysis from published reports between 1988 to 2003 and when analyzing data from a previously published clinical trial.11 However, in a 2010 report by Hawn et al analyzing the longterm outcomes for incisional hernia repair, there was no association with BMI on recurrence at a median follow-up of 73.4 months.16
More recent reports have suggested that BMI may in fact contribute to recurrence risk for ventral and umbilical hernia repairs; however, the relationship with absolute weight and increasing BMI category is unclear.12,13 There is also uncertainty as to how obesity could influence recurrenceewhether through impaired wound healing, abdominal wall tension, or technical difficulty at the index operation.11 However, there is good evidence that BMI itself is associated with an
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increased risk of SSO and overall complications.21,39,40 These data suggest that BMI may be an indirect contributor to recurrence by increasing the overall risk of surgical site infections, seromas, and other wound complications. In our study, we demonstrate that SSOs are the most important contributors to recurrence with a HR of 1.9 (95% CI 1.1e3.6, P ¼ .02). In a recent retrospective study, Owei et al found that 10.7% of patients undergoing open VHR have at least one 30-day postoperative complication and 6.9% suffer a surgical site complication, specifically superficial or deep incisional SSI, organ space SSI, or wound disruptions.24 In prospective studies, early postoperative complications were much more common and identified in up to 26% of patients after open VHR.22,35e38 A retrospective study of open retromuscular repair at a single institution showed that postoperative SSI was the only predictor of long-term hernia recurrence, and a separate retrospective cohort study showed a higher incidence of early SSOs in those patients with long-term hernia recurrence.26,28 These data support our finding that patients with 30-day postoperative SSO are at >2-fold risk for long-term ventral hernia recurrence relative to those without perioperative SSO. This effect is driven almost entirely by infectious complications, specifically superficial SSIs; however, with only 3 wound separation events in the full cohort, it is difficult to comment on their contribution when generalized to a larger scale. Our data suggest that ventral hernias should be considered as a chronic disease process. The risk of ventral hernia recurrence can extend up to 5 years postoperatively, which is in contrast to prior studies reporting that the majority of recurrences occur within 2 years postoperatively.9 Further, the vast majority of SSOs in our cohort were superficial SSIs suggesting that relatively minor complications can drastically affect long-term morbidity. Thus, although the linear association between BMI, smoking, and diabetes remains undetermined, focused efforts at smoking cessation and preoperative weight loss may indirectly increase the durability of repairs by decreasing the rate of SSO.41,42 This knowledge supports the use of techniques such as laparoscopic surgery, when appropriate and clinically indicated, given the lower rate of infectious complications with this approach, in addition to SSI reduction bundles and caution when operating in contaminated fields.43e47 However, this study also highlights the complexity of chronic ventral hernias and lends support to the goal of creating comprehensive hernia centers that may provide specialized and tailored care for these patients.48,49 In our institutional practice, we aim to minimize the development of SSO based on the evidence that SSOs are related to long-term recurrence. We optimize patients preoperatively by encouraging smoking cessation and glycemic control among diabetics to minimize SSOs. Our present study suggests that the relationship between BMI and recurrence is likely mediated through the development of SSOs, and we, therefore, selectively refer patients with a BMI >40 kg/m2 for bariatric surgery and/or medical weight loss before definitive VHR. There are several limitations to this study that warrant consideration. First, the retrospective nature of this study limited the granularity of the data that could be abstracted. Granularity is also limited when utilizing the NSQIP database, which does not include some components of the Ventral Hernia Working Group definition for SSO, such as stitch abscess or non-infected hematoma or seroma. Second, these findings are not based on randomized patient selection; thus, selection bias for open VHR approach cannot be controlled. Although we controlled for the operating surgeon, practice patterns for open VHR have evolved over the study period, which may affect the generalizability of results over time. In conclusion, overall, we found that almost 1 in 4 patients undergoing an open VHR will have a recurrence after 5 years. One in 6 patients undergoing an open VHR will undergo repair for a
recurrence. After controlling for patient comorbidities, hernia size, and mesh position, the most significant risk factor for recurrence after VHR was a non-primary hernia and SSO. Taken together, our findings suggest that ventral hernias should be considered a complex and chronic disease process with long-term morbidity. Efforts aimed at reducing rates of hernia recurrence should focus on providing specialized care to these complex patients with an aim to concurrently reduce the risk of SSIs and wound disruptions. Funding/Support This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Joshua Jolissaint receives support from the Weill Cornell Medical College Clinical and Translational Science Center funded by NIH/NCATS UL1TR002384. Conflict of interest/Disclosure Ali Tavakkoli, MD, served as a consultant for Medtronic. Thomas Tsai, MD, MPH, serves on the scientific advisory board for Seamless Mobile Health and served as a consultant for Sigilon Therapeutics. Supplementary materials Supplementary material associated with this article can be found, in the online version, at https://doi.org/10.1016/j.surg.2020. 01.001. References 1. Poulose BK, Shelton J, Phillips S, et al. Epidemiology and cost of ventral hernia repair: making the case for hernia research. Hernia. 2012;16:179e183. 2. Mason RJ, Moazzez A, Sohn HJ, Berne TV, Katkhouda N. Laparoscopic versus open anterior abdominal wall hernia repair: 30-day morbidity and mortality using the ACS-NSQIP database. Ann Surg. 2011;254:641e652. 3. Aher C, Kubasiak JC, Daly SC, et al. The utilization of laparoscopy in ventral hernia repair: an update of outcomes analysis using ACS-NSQIP data. Surg Endosc. 2015;29:1099e1104. 4. Burger JW, Luijendijk RW, Hop WC, et al. Long-term follow-up of a randomized controlled trial of suture versus mesh repair of incisional hernia. Ann Surg. 2004;240:578e585. 5. Luijendijk RW, Hop WC, van den Tol MP, et al. A comparison of suture repair with mesh repair for incisional hernia. N Engl J Med. 2000;343:392e398. 6. den Hartog D, Dur AH, Tuinebreijer WE, Kreis RW. Open surgical procedures for incisional hernias. Cochrane Database Syst Rev. 2008;(3):CD006438. 7. Helgstrand F, Rosenberg J, Kehlet H, Strandfelt P, Bisgaard T. Reoperation versus clinical recurrence rate after ventral hernia repair. Ann Surg. 2012;256: 955e958. €genur I, Rosenberg J. Long-term recurrence and 8. Andersen LP, Klein M, Go complication rates after incisional hernia repair with the open onlay technique. BMC Surg. 2009;9:6. 9. Singhal V, Szeto P, VanderMeer TJ, Cagir B. Ventral hernia repair: Outcomes change with long-term follow-up. JSLS. 2012;16:373e379. 10. Nguyen MT, Berger RL, Hicks SC, et al. Comparison of outcomes of synthetic mesh vs suture repair of elective primary ventral herniorrhaphy : a systematic review and meta-analysis. JAMA Surg. 2014;149:415e421. 11. Sauerland S, Korenkov M, Kleinen T, Arndt M, Paul A. Obesity is a risk factor for recurrence after incisional hernia repair. Hernia. 2004;8:42e46. 12. Stey AM, Russell MM, Sugar CA, et al. Extending the value of the National Surgical Quality Improvement Program claims dataset to study long-term outcomes: rate of repeat ventral hernia repair. Surgery. 2015;157:1157e1165. 13. Shankar DA, Itani KMF, O’Brien WJ, Sanchez VM. Factors associated with longterm outcomes of umbilical hernia repair. JAMA Surg. 2017;152:461e466. J, Torregrosa A, Jime nez-Rosello n R, García P, Bonafe S, Iserte J. 14. Bueno-Lledo Predictors of hernia recurrence after Rives-Stoppa repair in the treatment of incisional hernias: a retrospective cohort. Surg Endosc. 2019;33:2934e2940. 15. Holihan JL, Alawadi Z, Martindale RG, et al. Adverse events after ventral hernia repair: the vicious cycle of complications. J Am Coll Surg. 2015;221:478e485. 16. Hawn MT, Snyder CW, Graham LA, Gray SH, Finan KR, Vick CC. Long-term follow-up of technical outcomes for incisional hernia repair. J Am Coll Surg. 2010;210:655e657. 17. Hesselink VJ, Luijendijk RW, de Wilt JH, Heide R, Jeekel J. An evaluation of risk factors in incisional hernia recurrence. Surg Gynecol Obstet. 1993;176:228e234.
J.S. Jolissaint et al. / Surgery xxx (2020) 1e7 18. Kokotovic D, Bisgaard T, Helgstrand F. Long-term recurrence and complications associated with elective incisional hernia repair. JAMA. 2016;316:1575e1582. 19. Qin C, Souza J, Aggarwal A, Kim JY. Insulin dependence as an independent predictor of perioperative morbidity after ventral hernia repair: a National Surgical Quality Improvement Program analysis of 45,759 patients. Am J Surg. 2016;211:11e17. 20. Qin C, Hackett NJ, Kim JY. Assessing the safety of outpatient ventral hernia repair: a NSQIP analysis of 7666 patients. Hernia. 2015;19:919e926. 21. Pernar LIM, Pernar CH, Dieffenbach BV, Brooks DC, Smink DS, Tavakkoli A. What is the BMI threshold for open ventral hernia repair? Surg Endosc. 2017;31:1311e1317. 22. Eker HH, Hansson BM, Buunen M, et al. Laparoscopic vs open incisional hernia repair a randomized clinical trial. JAMA Surg. 2013;148:259e263. 23. Kroese LF, Gillion JF, Jeekel J, Lange JF, Kleinrensink GJ, and the Hernia-Club Members. Identification of risk factors for 30-day postoperative complications in patients undergoing primary ventral hernia repair: a prospective cohort study of 2,374 patients. Surgery. 2018;163:1160e1164. 24. Owei L, Swendiman RA, Kelz RR, Dempsey DT, Dumon KR. Impact of body mass index on open ventral hernia repair: a retrospective review. Surgery. 2017;162: 1320e1329. 25. Bleier JIS, Resnick AS. Complications of incisional hernia repair. Semin Colon Rectal Surg. 2009;20:125e130. 26. Cobb WS, Warren JA, Ewing JA, Burnikel A, Merchant M, Carbonell AM. Open retromuscular mesh repair of complex incisional hernia: predictors of wound events and recurrence. J Am Coll Surg. 2015;220:606e613. 27. Juvany M, Hoyuela C, Trias M, Carvajal F, Ardid J, Martrat A. Impact of surgical site infections on elective incisional hernia surgery: a prospective study. Surg Infect (Larchmt). 2018;19:339e344. 28. Warren JA, McGrath SP, Hale AL, Ewing JA. Carbonell AM 2nd, Cobb WS 4th. Patterns of recurrence and mechanisms of failure after open ventral hernia repair with mesh. Am Surg. 2017;83:1275e1282. 29. Fink AS, Campbell DA, Mentzer RM Jr, et al. The National Surgical Quality Improvement Program in non-veterans administration hospitals: initial demonstration of feasibility. Ann Surg. 2002;236:344e353; discussion 353e354. 30. Birkmeyer JD, Shahian DM, Dimick JB, et al. Blueprint for a New American College of Surgeons: National Surgical Quality Improvement Program. J Am Coll Surg. 2008;207:777e782. 31. Hall BL, Hamilton BH, Richards K, Bilimoria KY, Cohen ME, Ko CY. Does surgical quality improve in the American College of Surgeons National Surgical Quality Improvement Program: an evaluation of all participating hospitals. Ann Surg. 2009;250:363e376. 32. Muysoms FE, Miserez M, Berrevoet F, et al. Classification of primary and incisional abdominal wall hernias. Hernia. 2009;13:407e414. 33. Haskins I, Horne C, Krpata D, et al. A call for standardization of wound events reporting following ventral hernia repair. Hernia. 2018;22:729e736. 34. Centers for Disease Control and Prevention (CDC). Surgical site infection (SSI) event; 2017. https://www.cdc.gov/infectioncontrol/guidelines/ssi/index.html. Accessed October 20, 2019.
7
35. Rogmark P, Petersson U, Bringman S, et al. Short-term outcomes for open and laparoscopic midline incisional hernia repair: a randomized multicenter controlled trial: the ProLOVE (prospective randomized trial on open versus laparoscopic operation of ventral eventrations) trial. Ann Surg. 2013;258: 37e45. 36. Itani KMF, Hur K, Kim LT, et al. and the Veterans Affairs Ventral Incisional Hernia Investigators. Comparison of laparoscopic and open repair with mesh for the treatment of ventral incisional hernia: a randomized trial. Arch Surg. 2010;145:322e328; discussion 328. J, Peiro S, et al. Open randomized clinical trial of laparoscopic 37. Asencio F, Aguilo versus open incisional hernia repair. Surg Endosc. 2009;23:1441e1448. 38. Pring CM, Tran V, O’Rourke N, Martin IJ. Laparoscopic versus open ventral hernia repair: a randomized controlled trial. ANZ J Surg. 2008;78: 903e906. 39. Giordano SA, Garvey PB, Baumann DP, Liu J, Butler CE. The impact of body mass index on abdominal wall reconstruction outcomes: a comparative study. Plast Reconstr Surg. 2017;139:1234e1244. €wenmark T, Dahlstrand U, Gunnarsson U. Risk fac40. Lindmark M, Strigård K, Lo tors for surgical complications in ventral hernia repair. World J Surg. 2018;42: 3528e3536. 41. Chandeze MM, Moszkowicz D, Beauchet A, Vychnevskaia K, Peschaud F, Bouillot JL. Ventral hernia surgery in morbidly obese patients, immediate or after bariatric surgery preparation: results of a case-matched study. Surg Obes Relat Dis. 2019;15:83e88. 42. Saxony J, Cowling L, Catchpole L, Walker N. Evaluation of a smoking cessation service in elective surgery. J Surg Res. 2017;212:33e41. 43. Al Chalabi H, Larkin J, Mehigan B, McCormick P. A systematic review of laparoscopic versus open abdominal incisional hernia repair, with meta-analysis of randomized controlled trials. Int J Surg. 2015;20:65e74. 44. Kaafarani HMA, Kaufman D, Reda D, Itani KM. Predictors of surgical site infection in laparoscopic and open ventral incisional herniorrhaphy. J Surg Res. 2010;163:229e234. 45. Xourafas D, Lipsitz SR, Negro P, Ashley SW, Tavakkolizadeh A. Impact of mesh use on morbidity following ventral hernia repair with a simultaneous bowel resection. Arch Surg. 2010;145:739e744. 46. Hoang SC, Klipfel AA, Roth LA, Vrees M, Schechter S, Shah N. Colon and rectal surgery surgical site infection reduction bundle: to improve is to change. Am J Surg. 2019;217:40e45. 47. Cima R, Dankbar E, Lovely J, et al, and the Colorectal Surgical Site Infection Reduction Team. Colorectal surgery surgical site infection reduction program: a national surgical quality improvement programedriven multidisciplinary single-institution experience. J Am Coll Surg. 2013;216:23e33. 48. Raigani S, De Silva GS, Criss CN, Novitsky YW, Rosen MJ. The impact of developing a comprehensive hernia center on the referral patterns and complexity of hernia care. Hernia. 2014;18:625e630. €ckerling F, Sheen AJ, Berrevoet F, et al. Accreditation and certification re49. Ko quirements for hernia centers and surgeons: the ACCESS project. Hernia. 2019;23:185e203.