- Email: [email protected]
Randomized controlled trial comparing subcuticular absorbable suture with conventional interrupted suture for wound closure at elective operation of colon cancer
Randomized controlled trial comparing subcuticular absorbable suture with conventional interrupted suture for wound closure at elective operation of colon cancer Akira Tanaka, MD, PhD, Sotaro Sadahiro, MD, PhD, Toshiyuki Suzuki, MD, PhD, Kazutake Okada, MD, and Gota Saito, MD, Isehara, Kanagawa, Japan
Background. Subcuticular closure provides a superior cosmetic result in clean wounds. The aim of this work was to investigate the safety in terms of postoperative infection and cosmetic effectiveness of subcuticular wound closure after elective colon cancer surgery in clean-contaminated wounds. Methods. Patients who underwent elective resection of colon cancer were randomized to interrupted subcuticular and interrupted transdermal suture groups. The large bowel was prepared by mechanical washout with polyethylene glycol. All patients received metronidazole and kanamycin orally and flomoxef sodium once parenterally for antimicrobial prophylaxis. The primary end point was the incidence of incisional surgical-site infections within 30 days after operation. We assessed noninferiority of subcuticular suture within a margin of 10%. Analysis was by intent-to-treat. Secondary objectives include comparison of wound closure time, comfort, and cosmesis of the scar and satisfaction of patients. This study was registered with UMIN-CTR, UMIN000003005. Results. A total of 293 patients were randomized to the two groups. Incisional surgical-site infection rates were 11.0% (90% confidence interval 7.0–16.3%) for both groups. The relative risk of subcuticular suture was 1.00 (0.58–1.73, one-tail P = .57). Interrupted subcuticular suture was noninferior to interrupted transdermal suture (P = .0088). Throughout 6 months after operation, patients expressed a significant preference for the subcuticular suture technique, noting rapid relief from pain, decreased vascularity, and smaller width, although the procedure took twice as long. Conclusion. Subcuticular suture did not increase the incidence of wound complications in elective colon cancer operation. Patients preferred a technique of interrupted subcuticular closure, citing better cosmetic results, and less pain. (Surgery 2014;155:486-92.) Department of Surgery, Tokai University School of Medicine, Shiokasuya, Isehara, Kanagawa, Japan
THE DEGREE OF BACTERIAL CONTAMINATION during an operation is related to the risk of incisional infections.1 Although extensive clinical investigations into bowel preparations and antibiotics have resulted in lesser rates of infections, reported rates of incisional infections range from 6 to 36%
Presented at the 112th Annual Congress of Japan Surgical Society in April 2012, at Chiba, Japan (#PS017-3). Accepted for publication October 11, 2013. Reprint requests: Akira Tanaka, MD, PhD, Department of Surgery, Tokai University School of Medicine, 143 Shiokasuya, Isehara, Kanagawa, 259-1193, Japan. E-mail: [email protected]. u-tokai.ac.jp. 0039-6060/$ - see front matter Ó 2014 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.surg.2013.10.016
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among studies limited to elective operation for colorectal cancer.2-6 Wound closure with a subcuticular absorbable suture provides good cosmetic results with a rate of infection no greater than those found with conventional transdermal sutures and metallic staples in clean wounds, including wounds associated with orthopedic and obstetric surgery.7-9 An operative wound such as elective colon surgery in which the alimentary tract is entered under controlled conditions without unusual contamination is classified as Class II/Cleancontaminated in the 1999 guideline of the Centers for Disease Control and Prevention for the prevention of surgical site infections (SSIs).10 Subcuticular closure is occasionally used after elective colorectal surgery these days: however, the putative benefits have not been evaluated in a prospective trial.
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The aim of this randomized trial was to determine whether a subcuticular absorbable suture (polydioxanone acid [PDS II], Ethicon, Inc, Somerville, NJ) comparable with a conventional transdermal nonabsorbable (nylon) suture for the elective operation of colon cancer in terms of SSIs. Cosmetic outcomes of subcuticular sutures and traditional transdermal sutures also were compared over time to evaluate short- and longterm efficacy. METHODS Patients. We enrolled patients who were scheduled to receive elective colectomy through midline incision for histologically proven colon adenocarcinoma at Tokai University Hospital (Kanagawa, Japan). Patients who received laparoscopic colectomy, an ostomy procedure, multiple anastomoses or hepatic resection simultaneously, had a previous history of laparotomy or an active or uncontrolled infection, or who had received neoadjuvant chemotherapy or had been given steroids were excluded from the study. After confirming the eligibility of patients, we randomized patients to receive either subcuticular or transdermal closure. A minimization method was incorporated in the randomization to adjust baseline imbalance between the two groups in age (<65 and $65 years) and tumor locations (proximal, distal, and bilateral colons). The institutional review board for clinical research approved this study, and all patients provided written informed consent before randomization. This study was registered with the clinical trials registry of the University Hospital Medical Information Network (UMIN-CTR, UMIN000003005) in Japan. Procedure. All patients underwent the same bowel preparation and operative procedures. Sodium picosulfate 7.5 mg was administered 2 days before the operation. One day preoperatively, the large bowel was prepared by mechanical washout with polyethylene glycol given orally until the rectal effluent was clear.11 All patients orally received metronidazole 0.5 g and kanamycin 0.5 g three times daily. An intravenous drip infusion of flomoxef sodium 1 g (a second-generation cephem) was initiated 1 hour before we made an incision for parenteral antimicrobial prophylaxis. An additional dose of antibiotic was administered if the operation time exceeded 3 hours.6,12,13 The midline incision was protected with sterilized towels. Before wound closure, gloves and instruments were changed after abdominal
Tanaka et al 487
irrigation with 3 L of sterile saline. The linea alba and muscular layers were closed using an interrupted, 0 polydioxanone monofilament suture (PDS II ZB776D; Ethicon, Inc).14,15 The subcutaneous fat was irrigated with 300 mL of saline through syringe pressure before skin closure. Patients assigned to the subcuticular suture group had their wound closed with an interrupted, subcuticular, absorbable 4-0 polydioxanone suture on an atraumatic needle (PDS II Z771D; Ethicon, Inc). The interrupted knot inversion technique developed by Fiennes16 without adverse effects with respect to release of collected fluid was used instead of continuous subcuticular suture, and no fat stitch was used. Patients who received conventional sutures had their wound closed with an interrupted transdermal 3-0 nylon suture, and the suture was removed at 6 days postoperatively. Epidural techniques17 and intravenous flurbiprofen axetil were used for postoperative analgesia in both groups, although postoperative care was at the discretion of the surgeon. Assessment. The primary objective was to test the hypothesis that the incidence of incisional SSIs in patients who received a subcuticular suture is not greater (within a margin of 10%) than that in patients who received a standard transdermal suture after elective resection of colon cancer, ie, to demonstrate noninferiority of the subcuticular suture. Secondary objectives include comparison of the incidence of organ/space SSIs, the time for wound closure, comfort or cosmesis of the scar, and satisfaction of patients. Wound complications were assessed by one of the staff surgeons in the colorectal surgery department on day 7 during hospitalization. After the patient was discharged, the attending physicians at the outpatient department examined the wounds for complications and conducted patient satisfaction surveys on day 30, at 3 months, and then finally at 6 months after surgery. SSIs were classified as being either incisional (superficial and deep) or organ/space (with or without clinical leakage) according to the standardized surveillance criteria for defining SSIs.10,18 The definition of SSI includes purulent drainage with organisms isolated from culture, in addition to localized swelling and redness. We also assessed infections at remote sites that might influence wound infection rates adversely.19 Patients assigned overall satisfaction using the questionnaire regarding the appearance of the wound at each time point on a 10-step scale in which 10 corresponded to the best imaginable scar. The subjective scar assessment scale incorporated
488 Tanaka et al
parameters that were selected after a critical review of previous reports20-22 and on the basis of clinical experience, as follows: pain, vascularity, width, thickness, area of elevation or depression, suture sinus, and incisional hernia (the former five items each had 3 or 4 possible categories). Incisional hernia was defined as fascial dehiscence after completed superficial wound healing with a prolapse of abdominal organs confirmed by the attending physicians. Statistical analysis. Quantitative variables are given as mean ± SD, unless specified otherwise. Differences between groups were compared with Student t-test for quantitative variables and with a v2 test (with Fisher exact test where appropriate) for qualitative variables. All data were analyzed using IBM SPSS Statistics version 20 (IBM Japan, Ltd) and R version 2.15.0. Comparison of the incidence of SSIs between the two methods of wound closure was made under the hypothesis of equivalence, with the assumption that the incidence of SSIs with subcuticular sutures would not be inferior by an absolute difference of 10% (noninferiority margin) to that with conventional transdermal sutures. The SSI rate was assumed to be 12% or less with transdermal sutures based on the upper bound of the 90% confidence interval (90% CI) for the SSI rate of 8.4% that we reported previously.6 This margin is somewhat greater than that used in pivotal trials but may be justified on the ground that recent studies23-25 continue to show a wide range of prevalence (6–23%) of SSIs after wound closure in colorectal surgery. This analysis used the 90% CI of the difference of the rate of infections between the two methods of wound closure and a unilateral Dunnett-Gent test26; we calculated a priori that we would need 131 patients in each group to achieve a power of 80% with a one-sided significance level of a = .05.27 Accrual was halted after 146 patients had been enrolled in each group, after we took into account an estimated rate of 10% of patients lost to follow-up within 30 days. Analysis was by intent-to-treat. RESULTS Patient enrolment. Between November 2007 and November 2011, 293 patients with colon cancer who underwent elective open colectomy were randomized: 147 patients were assigned to the subcuticular suture group, and 146 patients received the conventional transdermal suture (Fig). Six-month follow-up of all patients was completed by April 2012. Within 30 days
Surgery March 2014
postoperatively we excluded from the noninferiority analysis 2 and 1 patients in the subcuticular and transdermal group, respectively, who underwent relaparotomy or died suddenly of acute myocardial infarction. At 6 months, three-fourths of each group had been included in assessment of wound complications and satisfaction scales. Baseline characteristics. The patients’ characteristics in the two groups were well balanced (Table I). Mean body mass index, preoperative physical status score, hemoglobin, albumin, and morbidity rate of diabetes were similar between the two groups. There was no difference in blood loss between the groups (P = .45); 10 patients received transfusions in each group (P = 1.0) because of preoperative anemia. Mean operative time was 10 minutes greater in the subcuticular suture group (131 vs 121 minutes, P = .0093). The length of the incisions did not differ between groups, but the time (minutes) to close the skin was greater in the subcuticular group (10.7 ± 2.8 vs 5.2 ± 1.5, P < .001). Primary end point. Incisional (superficial and deep) SSI rates were 11.0% (90% CI 7.0–16.3%) for both the subcuticular suture and transdermal suture groups (Table II). The relative risk of subcuticular suture was 1.00 (0.58–1.73, one-tail P = .57). Subcuticular suture was found to be non-inferior to transdermal suture in terms of incisional SSIs (P = .0088). Secondary end points. Other SSIs were comparable for organ or space (relative risk 0.75, 0.37– 1.51%; 0.80, 0.27–2.37 with and without anastomotic leakage, respectively), and for remote sites (0.67, 0.29–1.55, Table II). Throughout the follow-up, the patients expressed a preference for closure by subcuticular suture (Table III). DISCUSSION The ideal skin closure would be safe, effective, and rapid, be associated with minimal patient discomfort, and have a good cosmetic result.28 The subcuticular suture technique of wound closure is preferred in areas in which the best possible cosmetic result is desired. The subcuticular suture does not impact on deep tissues of the skin and leads to minimal strangulation of tissue,16 whereas the conventional interrupted transdermal suture leaves scars and cross-hatches that adversely influence the aesthetic outcome. This study is the first prospective randomized trial designed to compare SSI rates and cosmetic outcomes between a meticulously performed interrupted subcuticular suture and a standard interrupted transdermal suture in elective surgery for colon cancer.
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Tanaka et al 489
Fig. Flow diagram of trial participation. SC, Subcuticular suture; TD, transdermal suture; SSI, surgical-site infection.
Table I. Characteristics of patients P SC (n = 147) TD (n = 146) value Age, years 66.9 ± 11.5 66.7 ± 11.0 .86 Male 76 (51.7%) 87 (59.6%) .16 Body-mass index 22.2 ± 3.2 22.3 ± 3.3 .80 ASA PS 1.7 ± 0.7 1.9 ± 0.7 .12 Diabetes 13 (8.8%) 14 (9.6%) .84 Hemoglobin, g/dL 12.3 ± 2.4 12.2 ± 2.2 .72 Albumin, g/dL 4.1 ± 3.0 4.2 ± 4.3 .90 Site of tumor Proximal colon 58 (39.5%) 58 (39.7%) .22 Distal colon 87 (59.1%) 87 (59.6%) Bilateral colon 2 (1.4%) 1 (0.7%) pT stage Tis/T1/T2 28 (19.0%) 26 (17.8%) .63 T3/T4 119 (81.0%) 120 (82.2%) pN involvement 68 (46.3%) 72 (49.3%) .11 Operation time, min 131 ± 36 121 ± 23 .0093 Blood loss, mL 191 ± 178 175 ± 196 .45 Transfusion 10 (6.8%) 10 (6.8%) 1.0 Data are number or mean ± SD. ASA PS, American Society of Anesthesiologists physical status; pN, regional lymph node; pT, primary tumor; SC, subcuticular suture; TD, transdermal suture.
Several studies have compared the clinical benefits of subcuticular sutures with those of transdermal sutures or metallic staples. A metaanalysis of orthopedic procedures demonstrated
that the risk of wound infection was one-third less with sutures than with staples.7 Johnson et al8 reported that the risk of infection at Caesarean delivery was decreased with subcuticular sutures compared to staples, whereas Basha et al28 found that it was similar in the two techniques. In the case of clean incisions in coronary bypass patients, fewer complications, including erythema and drainage, were noted with subcuticular sutures, though there was no difference in the rate of infection between the two techniques.29 Every wound in those studies was classified as Class I/Clean, and therefore the safety and benefit of subcuticular sutures have not been established for Class II/Clean-contaminated wounds, that is, the category that includes wounds associated with elective colon surgery. In a mouse model of skin wounds contaminated with an intraoperative bacterial inoculum of Staphylococcus aureus, running subcuticular sutures were greatly inferior to staples.30 Our results showed that the incisional SSI rates were comparable at 11.0% (90% CI 7.0–16.3%) in both suture groups (Table II). Preliminary analysis of the present data did not find statistical significance for any of the risk factors18 associated with incisional SSI. Interrupted subcuticular suture was confirmed to be noninferior to the conventional suture with regard to the incidence of incisional SSIs. Various operative wound-handling techniques have been proposed to prevent wound infections,
490 Tanaka et al
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Table II. Incidence of surgical-site infections SC
SSIs Incisional Organ or space With AL Without AL RSIs
TD
x/n
% (90% CI)
x/n
% (90% CI)
RR (90% CI)
One-tail P value
16/145
11.0 (7.0–16.3)
16/145
11.0 (7.0–16.3)
1.00 (0.58–1.73)
.57
9/146 4/146 6/146
6.2 (3.3–10.5) 2.7 (0.9–6.2) 4.1 (1.8–7.9)
12/146 5/146 9/146
8.2 (4.8–13.0) 3.4 (1.4–7.1) 6.2 (3.3–10.5)
0.75 (0.37–1.51) 0.80 (0.27–2.37) 0.67 (0.29–1.55)
.33 .50 .30
AL, Anastomotic leakage; CI, confidence interval; RR, relative risk; RSI, remote-site infection; SC, subcuticular suture; SSI, surgical-site infection; TD, transdermal suture.
including pelvic drains, wound wicks, and subcutaneous drains,31 but most surgeons have paid relatively little attention to aesthetic outcomes after colon surgery. Taube et al32 first reported that the cosmetic results with 2-0 polypropylene (Prolene) subcuticular sutures were more acceptable than those with conventional interrupted sutures at the 4th postoperative week after acute appendectomy, though there was no difference in the cases of inguinal herniorrhaphy and saphenofemoral ligation. Zwart and de Ruiter33 found that the cosmetic results of wound closure with subcuticular 3-0 polydioxanone sutures were better, as early as the first month, than those obtained with either continuous monofilament polyamide (Ethylon) sutures or staples (Proximate 35W) after elective surgery for intra-abdominal or inguinal hernia. However, the differences among the three techniques had disappeared 6 months postoperatively. Scar tissue is usually distinguished from healthy skin by aberrant color, increased thickness, irregular surface area, loss of elasticity, and contraction or expansion of the surface area. The method of scar assessment should be reliable, consistent, and valid at all times, and also suitable for quick and simple application by the attending physicians. We used a modified scar assessment scale based on the Hollander Wound Evaluation22 and the Patient and Observer Scar Assessment Scale,20 which have been proven to be reproducible with good inter-observer agreement. In our trial, patients reported a significantly better aesthetic outcome, including the vascularity and width of wounds and greater overall satisfaction for the subcuticular absorbable suture over the transdermal nylon suture (Table III). The most frequently cited reason for their satisfaction was increased comfort and less pain with the subcuticular suture. Superiority over the conventional suture was apparent as early as 7 days postoperatively and
appeared to be aesthetically more pleasing at 6 months or more postoperation. Cassie et al34 reported that wound pain was less when skin was closed by the subcuticular technique in procedures for inguinal hernia, compared with the full-thickness nylon closure. Decreased pain may be accounted for by the considerably fewer free nerve endings involved by the subcuticular suture. In our study, superiority in terms of pain for midline wounds was demonstrated from 7 days postoperatively even though pain receptors in muscle and aponeurosis may be the major source of afferent impulses in abdominal surgery. Zwart and de Ruiter33 and Ranaboldo and Rowe Jones35 reported the mean rates of subcuticular closure with 3-0 polydioxanone suture as being 12.7 sec cm1 and 17.2 sec cm1, respectively. In contrast, our technique took 32.8 sec cm1 because of the interrupted technique used.16 The subcuticular method took twice as much procedure time to close the skin wound in agreement with early studies.16,34 The unit cost of the absorbable material (4-0 polydioxanone) is not considered to be a significant factor. Skin staples might cause less damage to tissues36 and is much quicker than sutures; however, Stockley and Elson37 noted increased pain when staples were used for wound closure in hip and knee surgery, together with increased risks of marginal necrosis and erythema. Metal staples are a more expensive option for wound closure. Cost differences, however would be attributed predominantly to the differences in operative time. In conclusion, use of a technique of interrupted subcuticular suture for wound closure after elective surgery for colon cancer was not associated with a greater risk of wound infection than a traditional transdermal suture. Even though the subcuticular suture takes double the time for wound closure, patients reported a significantly better aesthetic outcome and a clear overall preference for subcuticular suture.
7 days
Pain No pain Mild Moderate Severe Vascularity Normal Red Purple Width, mm <2 2–5 >5 Thickness, mm <2 2–5 >5 Area of elevation or depression Flat scar Local General Suture sinus Hernia OPS*
30 days
SC (n = 145)
TD (n = 145)
P valuey
SC (n = 145)
TD (n = 145)
112 27 5 1
62 66 14 3
<.001
133 11 1 0
110 28 6 1
102 36 7
51 80 14
<.001
114 31 0
49 93 3
124 20 1
96 47 2
<.001
137 7 1
139 6 0
142 3 0
.50
137 8 0 14 0 8.7 ± 1.9
143 2 0 20 1 6.6 ± 2.0
.10
.36 1.0 <.001
3 months P valuey
SC (n = 130)
TD (n = 126)
121 8 0 1
98 23 4 1
<.001
99 29 2
43 80 3
77 68 0
<.001
108 21 0
144 1 0
139 5 1
.15
144 1 0 2 0 9.0 ± 1.0
141 2 2 4 1 7.4 ± 1.4
.13
.68 1.0 <.001
P valuey
P valuey
SC (n = 111)
TD (n = 109)
105 6 0 0
88 18 3 0
<.001
84 26 1
47 60 2
<.001
39 83 5
<.001
89 21 1
29 77 3
<.001
127 3 0
118 8 0
.26
108 3 0
102 7 0
.21
128 2 0 1 0 8.9 ± 1.3
117 5 4 1 0 7.4 ± 1.3
.12
108 2 1 0 1 9.0 ± 0.9
102 4 3 0 2 7.3 ± 1.5
.25
.0081
.93 .41 <.001
.0053
– .62 <.001
Tanaka et al 491
*10 is the best possible score, 1 is the lowest possible score. yt-test for OPS and chi-square test (Fisher’s exact test) for the others with two-tail P value. OPS, Overall patients’ satisfaction; SC, subcuticular suture; TD, transdermal suture.
.0030
6 months
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Table III. Patient and observer scar assessment
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19. Edwards LD. The epidemiology of 2056 remote site infections and 1966 surgical wound infections occurring in 1865 patients: a four year study of 40,923 operations at Rush-Presbyterian-St. Luke’s Hospital, Chicago. Ann Surg 1976;184:758-66. 20. Draaijers L, Tempelman FRH, Botman YAM, Tuinebreijer W, Middelkoop E, Kreis R, et al. The patient and observer scar assessment scale: a reliable and feasible tool for scar evaluation. Plast Reconstr Surg 2004;113:1960-5. 21. van de Kar AL, Corion LUM, Smeulders MJC, Draaijers L, van der Horst CMAM, van Zuijlen PPM. Reliable and feasible evaluation of linear scars by the Patient and Observer Scar Assessment Scale. Plast Reconstr Surg 2005; 116:514-22. 22. HollanderJE,SingerAJ,ValentineS,HenryMC.Woundregistry: development and validation. Ann Emerg Med 1995;25:675-85. 23. Ishibashi K, Kuwabara K, Ishiguro T, Ohsawa T, Okada N, Miyazaki T, et al. Short-term intravenous antimicrobial prophylaxis in combination with preoperative oral antibiotics on surgical site infection and methicillin-resistant Staphylococcus aureus infection in elective colon cancer surgery: results of a prospective randomized trial. Surg Today 2009;39:1032-9. 24. Kao L, Ghaferi A, Ko C, Dimick J. Reliability of superficial surgical site infections as a hospital quality measure. J Am Coll Surg 2011;213:231-5. 25. Serra-Aracil X, Garcıa Domingo M, Pares D, Espin Basany E, Biondo S, Guirao X, et al. Surgical site infection in elective operations for colorectal cancer after the application of preventive measures. Arch Surg 2011;146:606-12. 26. Dunnett CW, Gent M. Significance testing to establish equivalence between treatments, with special reference to data in the form of 2 x 2 tables. Biometrics 1977;33:593-602. 27. Wittes J. Sample size calculations for randomized controlled trials. Epidemiol Rev 2002;24:39-53. 28. Basha S, Rochon M, Qui~ nones J, Coassolo K, Rust O, Smulian J. Randomized controlled trial of wound complication rates of subcuticular suture vs staples for skin closure at cesarean delivery. Am J Obstet Gynecol 2010;203:285.e1-8. 29. Johnson RG, Cohn WE, Thurer RL, McCarthy JR, Sirois CA, Weintraub RM. Cutaneous closure after cardiac operations: a controlled, randomized, prospective comparison of intradermal versus staple closures. Ann Surg 1997;226:606-12. 30. Stillman RM, Marino CA, Seligman SJ. Skin staples in potentially contaminated wounds. Arch Surg 1984;119:821-2. 31. MacFarlane SD, Ryan JA. Prevention of wound infection after elective colorectal resection. Am J Surg 1987;154:482-6. 32. Taube M, Porter RJ, Lord PH. A combination of subcuticular suture and sterile Micropore tape compared with conventional interrupted sutures for skin closure. A controlled trial. Ann R Coll Surg Engl 1983;65:164-7. 33. Zwart HJ, de Ruiter P. Subcuticular, continuous and mechanical skin closure: cosmetic results of a prospective randomized trial. Neth J Surg 1989;41:57-60. 34. Cassie AB, Chatterjee AK, Mehta S, Haworth JM. Pain quantum and wound healing: a comparison of interrupted inversion PDS and standard nylon sutures in abdominal skin closure. Ann R Coll Surg Engl 1988;70:339-42. 35. Ranaboldo CJ, Rowe Jones DC. Closure of laparotomy wounds: skin staples versus sutures. Br J Surg 1992;79:1172-3. 36. Johnson A, Rodeheaver GT, Durand LS, Edgerton MT, Edlich RF. Automatic disposable stapling devices for wound closure. Ann Emerg Med 1981;10:631-5. 37. Stockley I, Elson RA. Skin closure using staples and nylon sutures: a comparison of results. Ann R Coll Surg Engl 1987;69:76-8.
1. Grant SW, Hopkins J, Wilson SE. Operative site bacteriology as an indicator of postoperative infectious complications in elective colorectal surgery. Am Surg 1995;61:856-61. 2. Jagelman DG, Fabian TC, Nichols RL, Stone HH, Wilson SE, Zellner SR. Single-dose cefotetan versus multiple-dose cefoxitin as prophylaxis in colorectal surgery. Am J Surg 1988;155:71-6. 3. Schoetz DJ, Roberts PL, Murray JJ, Coller JA, Veidenheimer MC. Addition of parenteral cefoxitin to regimen of oral antibiotics for elective colorectal operations. A randomized prospective study. Ann Surg 1990;212:209-12. 4. Stone HH, Hooper CA, Kolb LD, Geheber CE, Dawkins EJ. Antibiotic prophylaxis in gastric, biliary and colonic surgery. Ann Surg 1976;184:443-52. 5. Kaiser AB, Herrington JL, Jacobs JK, Mulherin JL, Roach AC, Sawyers JL. Cefoxitin versus erythromycin, neomycin, and cefazolin in colorectal operations. Importance of the duration of the surgical procedure. Ann Surg 1983;198:525-30. 6. Suzuki T, Sadahiro S, Maeda Y, Tanaka A, Okada K, Kamijo A. Optimal duration of prophylactic antibiotic administration for elective colon cancer surgery: arandomized, clinical trial. Surgery 2011;149:171-8. 7. Smith TO, Sexton D, Mann C, Donell S. Sutures versus staples for skin closure in orthopaedic surgery: meta-analysis. BMJ 2010;340:c1199. 8. Johnson A, Young D, Reilly J. Caesarean section surgical site infection surveillance. J Hosp Infect 2006;64:30-5. 9. Shetty AA, Kumar VS, Morgan Hough C, Georgeu GA, James KD, Nicholl JE. Comparing wound complication rates following closure of hip wounds with metallic skin staples or subcuticular vicryl suture: a prospective randomised trial. J Orthop Surg 2004;12:191-3. 10. Mangram AJ, Horan TC, Pearson ML, Silver LC, Jarvis WR. Guideline for Prevention of Surgical Site Infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control 1999;27:97-132. 11. Zmora O, Wexner S, Hajjar L, Park T, Efron J, Nogueras J, et al. Trends in preparation for colorectal surgery: survey of the members of the American Society of Colon and Rectal Surgeons. Am Surg 2003;69:150-4. 12. Lewis RT. Oral versus systemic antibiotic prophylaxis in elective colon surgery: a randomized study and meta-analysis send a message from the 1990s. Can J Surg 2002;45:173-80. 13. Bratzler DW, Houck P, Calhoun JH, Dalton V, Daly C, Bonomo RA, et al. Antimicrobial Prophylaxis for Surgery: An Advisory Statement from the National Surgical Infection Prevention Project. Clin Infect Dis 2004;38:1706-15. 14. van ’t Riet M, Steyerberg EW, Nellensteyn J, Bonjer HJ, Jeekel J. Meta-analysis of techniques for closure of midline abdominal incisions. Br J Surg 2002;89:1350-6. 15. Sajid MS, Parampalli U, Baig MK, McFall MR. A systematic review on the effectiveness of slowly-absorbable versus non-absorbable sutures for abdominal fascial closure following laparotomy. Int J Surg 2011;9:615-25. 16. Fiennes AG. Interrupted subcuticular polyglactin sutures for abdominal wounds. Ann R Coll Surg Engl 1985;67:121. 17. Liu S, Wu C. The effect of analgesic technique on postoperative patient-reported outcomes including analgesia: a systematic review. Anesth Analg 2007;105:789-808. 18. Tang R, Chen HH, Wang YL, Changchien CR, Chen JS, Hsu KC, et al. Risk factors for surgical site infection after elective resection of the colon and rectum: a single-center prospective study of 2,809 consecutive patients. Ann Surg 2001;234:181-9.
Background. Subcuticular closure provides a superior cosmetic result in clean wounds. The aim of this work was to investigate the safety in terms of postoperative infection and cosmetic effectiveness of subcuticular wound closure after elective colon cancer surgery in clean-contaminated wounds. Methods. Patients who underwent elective resection of colon cancer were randomized to interrupted subcuticular and interrupted transdermal suture groups. The large bowel was prepared by mechanical washout with polyethylene glycol. All patients received metronidazole and kanamycin orally and flomoxef sodium once parenterally for antimicrobial prophylaxis. The primary end point was the incidence of incisional surgical-site infections within 30 days after operation. We assessed noninferiority of subcuticular suture within a margin of 10%. Analysis was by intent-to-treat. Secondary objectives include comparison of wound closure time, comfort, and cosmesis of the scar and satisfaction of patients. This study was registered with UMIN-CTR, UMIN000003005. Results. A total of 293 patients were randomized to the two groups. Incisional surgical-site infection rates were 11.0% (90% confidence interval 7.0–16.3%) for both groups. The relative risk of subcuticular suture was 1.00 (0.58–1.73, one-tail P = .57). Interrupted subcuticular suture was noninferior to interrupted transdermal suture (P = .0088). Throughout 6 months after operation, patients expressed a significant preference for the subcuticular suture technique, noting rapid relief from pain, decreased vascularity, and smaller width, although the procedure took twice as long. Conclusion. Subcuticular suture did not increase the incidence of wound complications in elective colon cancer operation. Patients preferred a technique of interrupted subcuticular closure, citing better cosmetic results, and less pain. (Surgery 2014;155:486-92.) Department of Surgery, Tokai University School of Medicine, Shiokasuya, Isehara, Kanagawa, Japan
THE DEGREE OF BACTERIAL CONTAMINATION during an operation is related to the risk of incisional infections.1 Although extensive clinical investigations into bowel preparations and antibiotics have resulted in lesser rates of infections, reported rates of incisional infections range from 6 to 36%
Presented at the 112th Annual Congress of Japan Surgical Society in April 2012, at Chiba, Japan (#PS017-3). Accepted for publication October 11, 2013. Reprint requests: Akira Tanaka, MD, PhD, Department of Surgery, Tokai University School of Medicine, 143 Shiokasuya, Isehara, Kanagawa, 259-1193, Japan. E-mail: [email protected]. u-tokai.ac.jp. 0039-6060/$ - see front matter Ó 2014 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.surg.2013.10.016
486 SURGERY
among studies limited to elective operation for colorectal cancer.2-6 Wound closure with a subcuticular absorbable suture provides good cosmetic results with a rate of infection no greater than those found with conventional transdermal sutures and metallic staples in clean wounds, including wounds associated with orthopedic and obstetric surgery.7-9 An operative wound such as elective colon surgery in which the alimentary tract is entered under controlled conditions without unusual contamination is classified as Class II/Cleancontaminated in the 1999 guideline of the Centers for Disease Control and Prevention for the prevention of surgical site infections (SSIs).10 Subcuticular closure is occasionally used after elective colorectal surgery these days: however, the putative benefits have not been evaluated in a prospective trial.
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The aim of this randomized trial was to determine whether a subcuticular absorbable suture (polydioxanone acid [PDS II], Ethicon, Inc, Somerville, NJ) comparable with a conventional transdermal nonabsorbable (nylon) suture for the elective operation of colon cancer in terms of SSIs. Cosmetic outcomes of subcuticular sutures and traditional transdermal sutures also were compared over time to evaluate short- and longterm efficacy. METHODS Patients. We enrolled patients who were scheduled to receive elective colectomy through midline incision for histologically proven colon adenocarcinoma at Tokai University Hospital (Kanagawa, Japan). Patients who received laparoscopic colectomy, an ostomy procedure, multiple anastomoses or hepatic resection simultaneously, had a previous history of laparotomy or an active or uncontrolled infection, or who had received neoadjuvant chemotherapy or had been given steroids were excluded from the study. After confirming the eligibility of patients, we randomized patients to receive either subcuticular or transdermal closure. A minimization method was incorporated in the randomization to adjust baseline imbalance between the two groups in age (<65 and $65 years) and tumor locations (proximal, distal, and bilateral colons). The institutional review board for clinical research approved this study, and all patients provided written informed consent before randomization. This study was registered with the clinical trials registry of the University Hospital Medical Information Network (UMIN-CTR, UMIN000003005) in Japan. Procedure. All patients underwent the same bowel preparation and operative procedures. Sodium picosulfate 7.5 mg was administered 2 days before the operation. One day preoperatively, the large bowel was prepared by mechanical washout with polyethylene glycol given orally until the rectal effluent was clear.11 All patients orally received metronidazole 0.5 g and kanamycin 0.5 g three times daily. An intravenous drip infusion of flomoxef sodium 1 g (a second-generation cephem) was initiated 1 hour before we made an incision for parenteral antimicrobial prophylaxis. An additional dose of antibiotic was administered if the operation time exceeded 3 hours.6,12,13 The midline incision was protected with sterilized towels. Before wound closure, gloves and instruments were changed after abdominal
Tanaka et al 487
irrigation with 3 L of sterile saline. The linea alba and muscular layers were closed using an interrupted, 0 polydioxanone monofilament suture (PDS II ZB776D; Ethicon, Inc).14,15 The subcutaneous fat was irrigated with 300 mL of saline through syringe pressure before skin closure. Patients assigned to the subcuticular suture group had their wound closed with an interrupted, subcuticular, absorbable 4-0 polydioxanone suture on an atraumatic needle (PDS II Z771D; Ethicon, Inc). The interrupted knot inversion technique developed by Fiennes16 without adverse effects with respect to release of collected fluid was used instead of continuous subcuticular suture, and no fat stitch was used. Patients who received conventional sutures had their wound closed with an interrupted transdermal 3-0 nylon suture, and the suture was removed at 6 days postoperatively. Epidural techniques17 and intravenous flurbiprofen axetil were used for postoperative analgesia in both groups, although postoperative care was at the discretion of the surgeon. Assessment. The primary objective was to test the hypothesis that the incidence of incisional SSIs in patients who received a subcuticular suture is not greater (within a margin of 10%) than that in patients who received a standard transdermal suture after elective resection of colon cancer, ie, to demonstrate noninferiority of the subcuticular suture. Secondary objectives include comparison of the incidence of organ/space SSIs, the time for wound closure, comfort or cosmesis of the scar, and satisfaction of patients. Wound complications were assessed by one of the staff surgeons in the colorectal surgery department on day 7 during hospitalization. After the patient was discharged, the attending physicians at the outpatient department examined the wounds for complications and conducted patient satisfaction surveys on day 30, at 3 months, and then finally at 6 months after surgery. SSIs were classified as being either incisional (superficial and deep) or organ/space (with or without clinical leakage) according to the standardized surveillance criteria for defining SSIs.10,18 The definition of SSI includes purulent drainage with organisms isolated from culture, in addition to localized swelling and redness. We also assessed infections at remote sites that might influence wound infection rates adversely.19 Patients assigned overall satisfaction using the questionnaire regarding the appearance of the wound at each time point on a 10-step scale in which 10 corresponded to the best imaginable scar. The subjective scar assessment scale incorporated
488 Tanaka et al
parameters that were selected after a critical review of previous reports20-22 and on the basis of clinical experience, as follows: pain, vascularity, width, thickness, area of elevation or depression, suture sinus, and incisional hernia (the former five items each had 3 or 4 possible categories). Incisional hernia was defined as fascial dehiscence after completed superficial wound healing with a prolapse of abdominal organs confirmed by the attending physicians. Statistical analysis. Quantitative variables are given as mean ± SD, unless specified otherwise. Differences between groups were compared with Student t-test for quantitative variables and with a v2 test (with Fisher exact test where appropriate) for qualitative variables. All data were analyzed using IBM SPSS Statistics version 20 (IBM Japan, Ltd) and R version 2.15.0. Comparison of the incidence of SSIs between the two methods of wound closure was made under the hypothesis of equivalence, with the assumption that the incidence of SSIs with subcuticular sutures would not be inferior by an absolute difference of 10% (noninferiority margin) to that with conventional transdermal sutures. The SSI rate was assumed to be 12% or less with transdermal sutures based on the upper bound of the 90% confidence interval (90% CI) for the SSI rate of 8.4% that we reported previously.6 This margin is somewhat greater than that used in pivotal trials but may be justified on the ground that recent studies23-25 continue to show a wide range of prevalence (6–23%) of SSIs after wound closure in colorectal surgery. This analysis used the 90% CI of the difference of the rate of infections between the two methods of wound closure and a unilateral Dunnett-Gent test26; we calculated a priori that we would need 131 patients in each group to achieve a power of 80% with a one-sided significance level of a = .05.27 Accrual was halted after 146 patients had been enrolled in each group, after we took into account an estimated rate of 10% of patients lost to follow-up within 30 days. Analysis was by intent-to-treat. RESULTS Patient enrolment. Between November 2007 and November 2011, 293 patients with colon cancer who underwent elective open colectomy were randomized: 147 patients were assigned to the subcuticular suture group, and 146 patients received the conventional transdermal suture (Fig). Six-month follow-up of all patients was completed by April 2012. Within 30 days
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postoperatively we excluded from the noninferiority analysis 2 and 1 patients in the subcuticular and transdermal group, respectively, who underwent relaparotomy or died suddenly of acute myocardial infarction. At 6 months, three-fourths of each group had been included in assessment of wound complications and satisfaction scales. Baseline characteristics. The patients’ characteristics in the two groups were well balanced (Table I). Mean body mass index, preoperative physical status score, hemoglobin, albumin, and morbidity rate of diabetes were similar between the two groups. There was no difference in blood loss between the groups (P = .45); 10 patients received transfusions in each group (P = 1.0) because of preoperative anemia. Mean operative time was 10 minutes greater in the subcuticular suture group (131 vs 121 minutes, P = .0093). The length of the incisions did not differ between groups, but the time (minutes) to close the skin was greater in the subcuticular group (10.7 ± 2.8 vs 5.2 ± 1.5, P < .001). Primary end point. Incisional (superficial and deep) SSI rates were 11.0% (90% CI 7.0–16.3%) for both the subcuticular suture and transdermal suture groups (Table II). The relative risk of subcuticular suture was 1.00 (0.58–1.73, one-tail P = .57). Subcuticular suture was found to be non-inferior to transdermal suture in terms of incisional SSIs (P = .0088). Secondary end points. Other SSIs were comparable for organ or space (relative risk 0.75, 0.37– 1.51%; 0.80, 0.27–2.37 with and without anastomotic leakage, respectively), and for remote sites (0.67, 0.29–1.55, Table II). Throughout the follow-up, the patients expressed a preference for closure by subcuticular suture (Table III). DISCUSSION The ideal skin closure would be safe, effective, and rapid, be associated with minimal patient discomfort, and have a good cosmetic result.28 The subcuticular suture technique of wound closure is preferred in areas in which the best possible cosmetic result is desired. The subcuticular suture does not impact on deep tissues of the skin and leads to minimal strangulation of tissue,16 whereas the conventional interrupted transdermal suture leaves scars and cross-hatches that adversely influence the aesthetic outcome. This study is the first prospective randomized trial designed to compare SSI rates and cosmetic outcomes between a meticulously performed interrupted subcuticular suture and a standard interrupted transdermal suture in elective surgery for colon cancer.
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Tanaka et al 489
Fig. Flow diagram of trial participation. SC, Subcuticular suture; TD, transdermal suture; SSI, surgical-site infection.
Table I. Characteristics of patients P SC (n = 147) TD (n = 146) value Age, years 66.9 ± 11.5 66.7 ± 11.0 .86 Male 76 (51.7%) 87 (59.6%) .16 Body-mass index 22.2 ± 3.2 22.3 ± 3.3 .80 ASA PS 1.7 ± 0.7 1.9 ± 0.7 .12 Diabetes 13 (8.8%) 14 (9.6%) .84 Hemoglobin, g/dL 12.3 ± 2.4 12.2 ± 2.2 .72 Albumin, g/dL 4.1 ± 3.0 4.2 ± 4.3 .90 Site of tumor Proximal colon 58 (39.5%) 58 (39.7%) .22 Distal colon 87 (59.1%) 87 (59.6%) Bilateral colon 2 (1.4%) 1 (0.7%) pT stage Tis/T1/T2 28 (19.0%) 26 (17.8%) .63 T3/T4 119 (81.0%) 120 (82.2%) pN involvement 68 (46.3%) 72 (49.3%) .11 Operation time, min 131 ± 36 121 ± 23 .0093 Blood loss, mL 191 ± 178 175 ± 196 .45 Transfusion 10 (6.8%) 10 (6.8%) 1.0 Data are number or mean ± SD. ASA PS, American Society of Anesthesiologists physical status; pN, regional lymph node; pT, primary tumor; SC, subcuticular suture; TD, transdermal suture.
Several studies have compared the clinical benefits of subcuticular sutures with those of transdermal sutures or metallic staples. A metaanalysis of orthopedic procedures demonstrated
that the risk of wound infection was one-third less with sutures than with staples.7 Johnson et al8 reported that the risk of infection at Caesarean delivery was decreased with subcuticular sutures compared to staples, whereas Basha et al28 found that it was similar in the two techniques. In the case of clean incisions in coronary bypass patients, fewer complications, including erythema and drainage, were noted with subcuticular sutures, though there was no difference in the rate of infection between the two techniques.29 Every wound in those studies was classified as Class I/Clean, and therefore the safety and benefit of subcuticular sutures have not been established for Class II/Clean-contaminated wounds, that is, the category that includes wounds associated with elective colon surgery. In a mouse model of skin wounds contaminated with an intraoperative bacterial inoculum of Staphylococcus aureus, running subcuticular sutures were greatly inferior to staples.30 Our results showed that the incisional SSI rates were comparable at 11.0% (90% CI 7.0–16.3%) in both suture groups (Table II). Preliminary analysis of the present data did not find statistical significance for any of the risk factors18 associated with incisional SSI. Interrupted subcuticular suture was confirmed to be noninferior to the conventional suture with regard to the incidence of incisional SSIs. Various operative wound-handling techniques have been proposed to prevent wound infections,
490 Tanaka et al
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Table II. Incidence of surgical-site infections SC
SSIs Incisional Organ or space With AL Without AL RSIs
TD
x/n
% (90% CI)
x/n
% (90% CI)
RR (90% CI)
One-tail P value
16/145
11.0 (7.0–16.3)
16/145
11.0 (7.0–16.3)
1.00 (0.58–1.73)
.57
9/146 4/146 6/146
6.2 (3.3–10.5) 2.7 (0.9–6.2) 4.1 (1.8–7.9)
12/146 5/146 9/146
8.2 (4.8–13.0) 3.4 (1.4–7.1) 6.2 (3.3–10.5)
0.75 (0.37–1.51) 0.80 (0.27–2.37) 0.67 (0.29–1.55)
.33 .50 .30
AL, Anastomotic leakage; CI, confidence interval; RR, relative risk; RSI, remote-site infection; SC, subcuticular suture; SSI, surgical-site infection; TD, transdermal suture.
including pelvic drains, wound wicks, and subcutaneous drains,31 but most surgeons have paid relatively little attention to aesthetic outcomes after colon surgery. Taube et al32 first reported that the cosmetic results with 2-0 polypropylene (Prolene) subcuticular sutures were more acceptable than those with conventional interrupted sutures at the 4th postoperative week after acute appendectomy, though there was no difference in the cases of inguinal herniorrhaphy and saphenofemoral ligation. Zwart and de Ruiter33 found that the cosmetic results of wound closure with subcuticular 3-0 polydioxanone sutures were better, as early as the first month, than those obtained with either continuous monofilament polyamide (Ethylon) sutures or staples (Proximate 35W) after elective surgery for intra-abdominal or inguinal hernia. However, the differences among the three techniques had disappeared 6 months postoperatively. Scar tissue is usually distinguished from healthy skin by aberrant color, increased thickness, irregular surface area, loss of elasticity, and contraction or expansion of the surface area. The method of scar assessment should be reliable, consistent, and valid at all times, and also suitable for quick and simple application by the attending physicians. We used a modified scar assessment scale based on the Hollander Wound Evaluation22 and the Patient and Observer Scar Assessment Scale,20 which have been proven to be reproducible with good inter-observer agreement. In our trial, patients reported a significantly better aesthetic outcome, including the vascularity and width of wounds and greater overall satisfaction for the subcuticular absorbable suture over the transdermal nylon suture (Table III). The most frequently cited reason for their satisfaction was increased comfort and less pain with the subcuticular suture. Superiority over the conventional suture was apparent as early as 7 days postoperatively and
appeared to be aesthetically more pleasing at 6 months or more postoperation. Cassie et al34 reported that wound pain was less when skin was closed by the subcuticular technique in procedures for inguinal hernia, compared with the full-thickness nylon closure. Decreased pain may be accounted for by the considerably fewer free nerve endings involved by the subcuticular suture. In our study, superiority in terms of pain for midline wounds was demonstrated from 7 days postoperatively even though pain receptors in muscle and aponeurosis may be the major source of afferent impulses in abdominal surgery. Zwart and de Ruiter33 and Ranaboldo and Rowe Jones35 reported the mean rates of subcuticular closure with 3-0 polydioxanone suture as being 12.7 sec cm1 and 17.2 sec cm1, respectively. In contrast, our technique took 32.8 sec cm1 because of the interrupted technique used.16 The subcuticular method took twice as much procedure time to close the skin wound in agreement with early studies.16,34 The unit cost of the absorbable material (4-0 polydioxanone) is not considered to be a significant factor. Skin staples might cause less damage to tissues36 and is much quicker than sutures; however, Stockley and Elson37 noted increased pain when staples were used for wound closure in hip and knee surgery, together with increased risks of marginal necrosis and erythema. Metal staples are a more expensive option for wound closure. Cost differences, however would be attributed predominantly to the differences in operative time. In conclusion, use of a technique of interrupted subcuticular suture for wound closure after elective surgery for colon cancer was not associated with a greater risk of wound infection than a traditional transdermal suture. Even though the subcuticular suture takes double the time for wound closure, patients reported a significantly better aesthetic outcome and a clear overall preference for subcuticular suture.
7 days
Pain No pain Mild Moderate Severe Vascularity Normal Red Purple Width, mm <2 2–5 >5 Thickness, mm <2 2–5 >5 Area of elevation or depression Flat scar Local General Suture sinus Hernia OPS*
30 days
SC (n = 145)
TD (n = 145)
P valuey
SC (n = 145)
TD (n = 145)
112 27 5 1
62 66 14 3
<.001
133 11 1 0
110 28 6 1
102 36 7
51 80 14
<.001
114 31 0
49 93 3
124 20 1
96 47 2
<.001
137 7 1
139 6 0
142 3 0
.50
137 8 0 14 0 8.7 ± 1.9
143 2 0 20 1 6.6 ± 2.0
.10
.36 1.0 <.001
3 months P valuey
SC (n = 130)
TD (n = 126)
121 8 0 1
98 23 4 1
<.001
99 29 2
43 80 3
77 68 0
<.001
108 21 0
144 1 0
139 5 1
.15
144 1 0 2 0 9.0 ± 1.0
141 2 2 4 1 7.4 ± 1.4
.13
.68 1.0 <.001
P valuey
P valuey
SC (n = 111)
TD (n = 109)
105 6 0 0
88 18 3 0
<.001
84 26 1
47 60 2
<.001
39 83 5
<.001
89 21 1
29 77 3
<.001
127 3 0
118 8 0
.26
108 3 0
102 7 0
.21
128 2 0 1 0 8.9 ± 1.3
117 5 4 1 0 7.4 ± 1.3
.12
108 2 1 0 1 9.0 ± 0.9
102 4 3 0 2 7.3 ± 1.5
.25
.0081
.93 .41 <.001
.0053
– .62 <.001
Tanaka et al 491
*10 is the best possible score, 1 is the lowest possible score. yt-test for OPS and chi-square test (Fisher’s exact test) for the others with two-tail P value. OPS, Overall patients’ satisfaction; SC, subcuticular suture; TD, transdermal suture.
.0030
6 months
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Table III. Patient and observer scar assessment
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1. Grant SW, Hopkins J, Wilson SE. Operative site bacteriology as an indicator of postoperative infectious complications in elective colorectal surgery. Am Surg 1995;61:856-61. 2. Jagelman DG, Fabian TC, Nichols RL, Stone HH, Wilson SE, Zellner SR. Single-dose cefotetan versus multiple-dose cefoxitin as prophylaxis in colorectal surgery. Am J Surg 1988;155:71-6. 3. Schoetz DJ, Roberts PL, Murray JJ, Coller JA, Veidenheimer MC. Addition of parenteral cefoxitin to regimen of oral antibiotics for elective colorectal operations. A randomized prospective study. Ann Surg 1990;212:209-12. 4. Stone HH, Hooper CA, Kolb LD, Geheber CE, Dawkins EJ. Antibiotic prophylaxis in gastric, biliary and colonic surgery. Ann Surg 1976;184:443-52. 5. Kaiser AB, Herrington JL, Jacobs JK, Mulherin JL, Roach AC, Sawyers JL. Cefoxitin versus erythromycin, neomycin, and cefazolin in colorectal operations. Importance of the duration of the surgical procedure. Ann Surg 1983;198:525-30. 6. Suzuki T, Sadahiro S, Maeda Y, Tanaka A, Okada K, Kamijo A. Optimal duration of prophylactic antibiotic administration for elective colon cancer surgery: arandomized, clinical trial. Surgery 2011;149:171-8. 7. Smith TO, Sexton D, Mann C, Donell S. Sutures versus staples for skin closure in orthopaedic surgery: meta-analysis. BMJ 2010;340:c1199. 8. Johnson A, Young D, Reilly J. Caesarean section surgical site infection surveillance. J Hosp Infect 2006;64:30-5. 9. Shetty AA, Kumar VS, Morgan Hough C, Georgeu GA, James KD, Nicholl JE. Comparing wound complication rates following closure of hip wounds with metallic skin staples or subcuticular vicryl suture: a prospective randomised trial. J Orthop Surg 2004;12:191-3. 10. Mangram AJ, Horan TC, Pearson ML, Silver LC, Jarvis WR. Guideline for Prevention of Surgical Site Infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control 1999;27:97-132. 11. Zmora O, Wexner S, Hajjar L, Park T, Efron J, Nogueras J, et al. Trends in preparation for colorectal surgery: survey of the members of the American Society of Colon and Rectal Surgeons. Am Surg 2003;69:150-4. 12. Lewis RT. Oral versus systemic antibiotic prophylaxis in elective colon surgery: a randomized study and meta-analysis send a message from the 1990s. Can J Surg 2002;45:173-80. 13. Bratzler DW, Houck P, Calhoun JH, Dalton V, Daly C, Bonomo RA, et al. Antimicrobial Prophylaxis for Surgery: An Advisory Statement from the National Surgical Infection Prevention Project. Clin Infect Dis 2004;38:1706-15. 14. van ’t Riet M, Steyerberg EW, Nellensteyn J, Bonjer HJ, Jeekel J. Meta-analysis of techniques for closure of midline abdominal incisions. Br J Surg 2002;89:1350-6. 15. Sajid MS, Parampalli U, Baig MK, McFall MR. A systematic review on the effectiveness of slowly-absorbable versus non-absorbable sutures for abdominal fascial closure following laparotomy. Int J Surg 2011;9:615-25. 16. Fiennes AG. Interrupted subcuticular polyglactin sutures for abdominal wounds. Ann R Coll Surg Engl 1985;67:121. 17. Liu S, Wu C. The effect of analgesic technique on postoperative patient-reported outcomes including analgesia: a systematic review. Anesth Analg 2007;105:789-808. 18. Tang R, Chen HH, Wang YL, Changchien CR, Chen JS, Hsu KC, et al. Risk factors for surgical site infection after elective resection of the colon and rectum: a single-center prospective study of 2,809 consecutive patients. Ann Surg 2001;234:181-9.