Arch Gynecol Obstet DOI 10.1007/s00404-013-3098-z
MATERNAL-FETAL MEDICINE
Superficial incisional surgical site infection rate after cesarean section in obese women: a randomized controlled trial of subcuticular versus interrupted skin suturing Moustafa I. Ibrahim • Gamal Farag Moustafa • Ahmed Sherif Abd Al-Hamid • May Raafat Hussein
Received: 15 November 2012 / Accepted: 14 November 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract Purpose To compare the superficial incisional surgical site infection (SSI) rate after cesarean section (CS) in obese women using subcuticular versus interrupted skin suturing. Methods The current randomized controlled clinical trial was conducted at Ain Shams University Maternity Hospital. Obese non-diabetic women who underwent elective CS were randomized into two groups: group I included women who had their skin closed with interrupted mattress suture using non-absorbable polypropylene, and group II included women who had their skin closed with subcuticular suture using the same suture material. Primary outcome measure was superficial incisional SSI and secondary outcome measures were skin closure time, postoperative pain assessed by ten-point visual analog scale (VAS) and shortterm cosmetic wound outcome according to the Stony Brook Scar Evaluation Scale (SBSES). Results A total of 130 obese women were finally analyzed. Group II (n = 67) was associated with higher incidence of superficial incisional SSI. There were nine cases (13.4 %) compared to three cases (4.8 %) in group I Trial registration: Clinical Trials.gov, NCT01713751. M. I. Ibrahim (&) G. F. Moustafa A. S. A. Al-Hamid M. R. Hussein Department of Obstetrics and Gynecology, Ain Shams University, Building Number 112, El Marwa Tower, Walee EL Ahd Street, Hadayk EL-Kobba, Cairo, Egypt e-mail: [email protected]
(n = 63); however, this difference was statistically not significant (P = 0.088). Skin closure time was significantly prolonged in group I (8.6 ± 2.3 min versus 5.7 ± 2.2 min, respectively, P \ 0.001). Postoperative pain was significantly lower in group I and the mean VAS in group I was 4.7 ± 2 versus 5.5 ± 1.8 in group II (P = 0.017). Using SBSES, group II had mean score 4.5 ± 0.7, while group I had mean score 2.7 ± 1.1. This was statistically significant (P \ 0.001), which means a better cosmetic outcome in group II. Conclusion Subcuticular skin closure during CS for nondiabetic obese women was significantly associated with better short-term cosmetic outcome, less skin closure time, yet, with slightly higher risk of superficial incisional SSI and significantly more postoperative pain. Keywords Surgical site infection Skin closure Cesarean section Abbreviations BMI Body mass index CS Cesarean section SBSES Stony Brook Scar Evaluation Scale SSI Surgical site infection VAS Visual analog scale
G. F. Moustafa e-mail: [email protected]
Introduction
A. S. A. Al-Hamid e-mail: [email protected]
Although several factors contribute to cesarean wound complications, the optimal method of skin closure to minimize these complications is unknown [1]. The two large-scale international trials, CAESAR study and
M. R. Hussein e-mail: [email protected]
123
Arch Gynecol Obstet
CORONIS trial, are underway comparing different techniques of cesarean delivery; however, none evaluates the methods of skin closure [2]. As the incidence of obesity rises, it contributes not only to the increase in cesarean section (CS), but also to post-cesarean wound complications, including infections, seromas, dehiscence and hematomas that are becoming more prevalent [3]. The skin layer can be repaired by subcuticular stitch (immediately below the skin layer), an interrupted stitch (individual stitches) or with skin staples. A survey of skin closure techniques used in the UK showed that the subcuticular skin stitch was the most commonly used (73.9 %) followed by interrupted skin stitch (7.7 %) and others (18.4 %) [4]. Surgical site infection (SSI) is a common complication of surgery. Infection has always been a feature of modern surgery and continues to be a significant problem for health-care practitioners across the world. SSI is a common and major cause of postoperative morbidity. Its morbidities range from delayed healing to systemic sepsis [5]. The aim of the present study was to compare the superficial incisional SSI rate after CS in obese women using subcuticular versus interrupted skin suturing.
Patients and methods The current randomized controlled clinical trial was conducted at Ain Shams University Maternity Hospital, Cairo, Egypt, during the period from March 2012 to August 2012. The study was approved by the Ethical and Research Committee of the Council of Obstetrics and Gynecology Department, Ain Shams University. The study purpose and procedures were explained to all enrolled women and a written informed consent was obtained from each participant. The study included women planned for elective CS. Elective CS is defined as that done at a time to suit the woman and the maternity team [6]. Randomization was done using computer-generated system. The random sequence was printed on identical sheets of paper, put in sealed opaque envelopes and kept with the head nurse of the labor ward. Group assignment was determined preoperatively when the patient fulfilled the study eligibility criteria. Demographic information collected included patient’s age, parity, body mass index (BMI), gestational age at delivery, indication for cesarean section, and medical and surgical histories. Women who had concurrent overt infection (e.g., chorioamnionitis, pyelonephritis or chest infection), intraoperative events that may themselves predispose to perioperative infection (e.g., bowel injury, operative time more than 90 min, major blood loss), hemoglobin less than 10 g/dl, pre-eclampsia, diabetes mellitus or rupture of membranes for more than 12 h, those on immunosuppressive drugs and those who had nonPfannenstiel incision, nonelective cesarean section or BMI
123
\30 kg/m2 were excluded from the study. Our study calculated the BMI of patients from their weight and height at admission, because the BMI at admission was a better indicator of body mass during the at-risk time for development of SSI than the pre-pregnancy BMI. The included women were randomized into one of the following two groups: group I including women who have their skin closed with interrupted mattress stitches using non-absorbable polypropylene ProleneÒ2.0 (Ethicon, Johnson & Johnson Ltd, Aurangabad, Maharashtra, India) and group II including women who had their skin closed with subcuticular stitches using the same suture material. All CS procedures were performed by surgeons who had at least 2 years experience in performing cesarean sections. All the participants were operated under spinal anesthesia. Antibiotic prophylaxis was given, as advised by the local protocols of Ain Shams University Maternity Hospital, as two intravenous doses of broad-spectrum penicillin (after clamping of the umbilical cord and 12 h postoperatively). Oral antibiotic of the same group was then given for 3–5 days. The abdomen was scrubbed starting from the level of the umbilicus till the mid-thigh, using povidone iodine 10 % (BetadineÒ) antiseptic solution. Any scar of previous CS was removed. After closure of the fascial layer, subcutaneous tissue was closed if it was deeper than 2 cm. Patients who needed subcutaneous drain were excluded from the final analysis. The protocol of our hospital is to close the subcutaneous tissue with interrupted stitches using nonabsorbable polyglactin 910 VicrylÒ2.0 (Ethicon, Johnson & Johnson Ltd, Aurangabad, Maharashtra, India). A metaanalysis of three studies including 875 patients authenticated that suture closure of subcutaneous fat during CS resulted in a 34 % decrease in the risk of wound disruption in women with fat thickness [2 cm [7]. Wound was uncovered 24 h postoperatively, and then dressed with alcohol 70 % antiseptic solution for 7 days The wound was inspected after 48 h, 7 days and 1 month after the CS. A superficial incisional SSI must meet the following criteria: infection occurs within 30 days after the operative procedure and involves only the skin and subcutaneous tissue of the incision. A deep incisional SSI means that infection occurs within 30 days after the operative procedure if no implant is left in place or within 1 year if implant is in place, and the infection appears to be related to the operative procedure and involves deep soft tissues (e.g., fascial and muscle layers) of the incision [8]. Pain was measured 48 h after CS using ten-point visual analog scale (VAS) from 0 to 10, with 0 indicating no pain and 10 indicating worst conceivable pain. Short-term cosmetic wound outcome (for 1 month postoperatively) was assessed using the Stony Brook Scar Evaluation Scale (SBSES) [9]. Primary outcome measure was surgical site
Arch Gynecol Obstet Fig. 1 CONSORT 2010 flow diagram
CONSORT 2010 Flow Diagram Enrollment
Assessed for eligibility (n=510)
Excluded (n=370) ♦Not meeting inclusion criteria (n=350) ♦ Declined to participate (n=20)
Randomized (n= 140)
Allocation ♦ Allocated
to interrupted mattress suture group (n=68)
♦ Allocated to subcuticular suture group intervention (n= 72)
Follow -Up ♦ Lost to follow-up (didn't come for follow up visit due to long distance between their residence and our hospital) (n=1)
♦ Lost to follow-up (didn't come for follow up visit due to long distance between their residence and our hospital) (n=1)
Analysis Analysed (n=63) ♦ Excluded from analysis (needed subcutaneous drain) (n=4)
infection during the 1 month study duration, according to the definition devised and adopted by the Centers for Disease Control and Prevention (CDC) [8]. Secondary outcome measures were skin closure time, postoperative pain assessed by ten-point VAS and short-term cosmetic wound outcome using SBSES. This scale is designed to measure the short-term cosmetic outcome of the wound ranging from 0 (the worst) to 5 (the best) [9]. Outcomes were assessed by a neutral investigator who was the first author (Ibrahim M.I.) with 15 years experience in obstetric practice and he played no role in the surgical procedures and/or group allocation.
Sample size justification Sample size was calculated using EpiInfoÒ version 6.0, setting the type-1 error (a) at 0.05 and the power (1-b) at 0.8. Data from a previous study showed that the incidence of post-CS SSI in obese women was 18.4 % [10].Calculation according to these values to give the least statistically acceptable figure produced a minimal sample size of 62 cases in each group. Assuming a dropout rate of 5 %, the minimal sample size was 65 cases in each group.
Analysed (n= 67) ♦ Excluded from analysis (needed subcutaneous drain) (n=4)
Therefore, a minimum of 130 women were to be recruited in the trial, to be randomized into one of the two groups. Statistical analysis The collected data were coded, tabulated and statistically analyzed using the SPSS program (Statistical Package for Social Sciences) software version 18.0. Descriptive statistics were done for numerical parametric data as mean ± SD (standard deviation), while they were done for categorical data as number and percentage. Inferential analyses were done for quantitative variables using independent t test in case of two independent groups with parametric data. Inferential analyses were done for qualitative data using v2 test for independent variables. The significant level was set at 0.05.
Results A total of 140 women were included in the study. The included women were randomly divided into two groups: group I (n = 68) and group II (n = 72). Five patients in
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Arch Gynecol Obstet Table 1 Demographic characteristics of the study groups Group I (N = 63)
Group II (N = 67)
P
30.2 ± 6.0
29.2 ± 3.6
0.273**
Primigravida
3 (4.8 %)
1 (1.5 %)
0.281***
Multigravida
60 (95.2 %)
66 (98.5 %)
Age (years) Parity
BMI (kg/m2)
36.4 ± 5.2
37.5 ± 4.1
0.177**
Gestational age (weeks)
38.5 ± 1.2
38.7 ± 1.2
0.384**
3 (4.5 %)
0.465***
Indications for cesarean section Infertility and bad 6 (9.5 %) obstetric history Repeat CS
52 (82.5 %)
Discussion
52 (77.6 %)
Breech
2 (3.2 %)
5 (7.5 %)
Maternal request
0 (0.0 %)
2 (3.0 %)
Advanced maternal age
2 (3.2 %)
2 (3.0 %)
Non-reassuring fetal condition
1 (1.6 %)
3 (4.5 %)
Values are expressed as mean ± SD, or numbers (%) BMI Body mass index, cs cesarean section ** Analysis using independent t test *** Analysis using Chi-square (v2) test
Table 2 Comparison between both groups regarding surgical site complications Complications
Group I (N = 63)
Group II (N = 67)
P**
Surgical site infection
3 (4.8 %)
9 (13.4 %)
0.088
Serous discharge
5 (7.9 %)
2 (3.0 %)
0.211
Serosanguinous discharge
2 (3.2 %)
0 (0.0 %)
0.142
Bloody discharge
1 (1.6 %)
0 (0.0 %)
0.301
Wound disruption
0 (0.0 %)
2 (3.0 %)
0.167
Problem in stitch removal
3 (4.8 %)
2 (3.0 %)
0.599
Values are expressed as numbers (%) ** Analysis using Chi-square (v2) test
both groups withdrew from the study. So, a total of 130 obese women were finally analyzed. Group I included 63 obese women, while group II included 67 obese women. The flow of women through the study is shown in Fig. 1. The demographic characteristics are shown in Table 1. There were no statistically significant differences between both groups regarding age, parity, BMI, gestational ages at termination and indications for CS in both groups. Skin closure time was significantly prolonged in group I (8.6 ± 2.3 versus 5.7 ± 2.2 min, respectively; P \ 0.001). Comparison between both groups regarding surgical site
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complications is shown in Table 2. No deep incisional SSI was noticed in both groups. Postoperative pain was significantly lower in group I. The mean VAS in group I was 4.7 ± 2 versus 5.5 ± 1.8 in group II (P = 0.017). Using SBSES, group II had a mean score of 4.5 ± 0.7, while group I had a mean score of 2.7 ± 1.1. This was statistically significant (P \ 0.001), which means a better cosmetic outcome in group II.
To our knowledge, no previous studies have addressed the effect of skin closure methods on the incidence of SSI in obese patients who underwent cesarean sections. In our institute, Ain Shams University Maternity Hospital, surgeons usually close the skin of obese women undergoing cesarean sections with non-absorbable interrupted sutures. This may be due to the belief that interrupted sutures allow drainage in addition to the possibility of removal of one or two stitches in the presence of any collection without disruption of the whole wound, as obese women are more prone to wound complication, which will not be possible to perform with the continuous subcuticular technique. On reviewing the literature, we did not find any clear recommendation concerning skin closure in obese women or any high-risk group liable for wound complications. Yet, we identified two systematic reviews and one metaanalysis evaluating skin closure techniques in obstetrics and gynecology. The first review was done by Altman et al. [11] and included five animal and ten human studies: five of which were not related to obstetrics and gynecology. The second review was conducted by Tuuli et al. [2] and included three additional studies which were RCTs, except for one prospective cohort study. Clay et al. [12] included in their meta-analysis the five RCTs that were identified by Tuuli et al. [2]. In this meta-analysis, studies mainly compared the skin closure techniques, whether subcuticular or interrupted, with staples. The five trials randomized 877 women to either technique. Follow-up ranged from 2 weeks to 6 months. The staples group was associated with higher incidence of wound complications (OR 2.12, 95 % CI 1.29–3.48; five trials). Even after exclusion of the study with the highest complication rates, the final analysis was the same. Insufficient data were available to assess postoperative pain or patient satisfaction in this metaanalysis [12]. McLean et al. [13] conducted another RCT to compare subcuticular sutures with interrupted sutures in patients undergoing laparotomy. They concluded that the subcuticular method was quicker and cheaper. Onwuanyi and Evbuomwan [14] compared the subcuticular with interrupted non-absorbable sutures after an uncomplicated appendectomy and found significantly more complications
Arch Gynecol Obstet
such as pain, itching and scar hypertrophy in the interrupted closure group. The overall infection rate (6 %) was evenly distributed in both groups. Their conclusion was that the subcuticular method was safe at any age and offered cost and time-saving advantage. As for our findings, skin closure time was significantly prolonged in interrupted sutures group (P \ 0.001), which agreed with all the previous studies [13, 14]. The subcuticular group was associated with a higher incidence of superficial incisional SSI using the definition of CDC [8]. There were nine (13.4 %) cases in the subcuticular suture group compared to three (4.8 %) in the interrupted suture group; yet this difference was not of statistical significance (P = 0.088). Mclean et al. in their RCT found that infection rates were equally distributed between the two groups; there were two cases in each group representing 3.9 and 3.7 %, respectively [12]. Onwuanyi and Evbuomwan [14] also showed that the infection rates were equally distributed between the two groups (three cases in each group, each containing 50 women). Postoperative pain, assessed by ten-point VAS, was significantly lower in the interrupted sutures group (P = 0.017), which was not assessed by either Mclean et al. [13] or Onwuanyi and Evbuomwan [14]. However, Tuuli et al. [2] in their meta-analysis found that the two closure techniques appeared equivalent in terms of postoperative pain. Using SBSES, the subcuticular group had amean score of 4.5 ± 0.7, while the interrupted group had a mean score of 2.7 ± 1.1; this difference was statistically significant (P \ 0.001). This agreed with the study done by Frishman et al. [15] who found that wound cosmosis (using the categories excellent, good, fair and poor) was superior in patients with subcuticular suture closure compared with staples, as rated by the patients (P = 0.04) and physicians (P = 0.01). This was not in line with McLean et al. [13] where the wound was assessed after 1 month by independent observers and all wounds were considered satisfactory. This might be due to differences in the population, type of operations and incisions. Rousseau et al. [16] and Cromi et al. [17] reported that the staples and subcuticular sutures were equivalent regarding their cosmetic outcome. This might be attributed to the longer duration of follow-up (6 weeks and 6 months respectively). The strengths of our study included randomization design, which disabled all personnel involved in the study from knowing the groups’ allocation. Blinding was not feasible due to the obvious nature of the two techniques; however, bias was relatively controlled through concealment of the
allocation in addition to assessment of the outcomes by a neutral investigator. This is, to our knowledge, the first study that addressed the effect of skin closure methods on the incidence of SSI in obese women undergoing cesarean section. Another strength of this study was selection of obese non-diabetic patients, so as to exclude another risk factor that might predispose to SSI. Using VAS and SBSES for postoperative assessment of pain and wound cosmosis was an additional strengthening point and helped us to compare different methods of skin closure in this group of women. Our study was limited by the short period of follow-up being 1 month; which was attributed to the difficulty in convincing these women to come for visits unless they had wound complications. Another limitation was that the difference between the two groups regarding the rate of superficial incisional SSI was shown to be statistically close to significance (P = 0.088). This may raise a question mark on the power of the study. Observers of the results would assume different (i.e. significant) results if the sample size was bigger. However, the sample size was calculated using a standard sample size calculator (EpiInfoÒ version 6) relying on previously published data [10]. Conclusion Subcuticular skin closure during CS for non-diabetic obese women was significantly associated with better short-term cosmetic outcome and less skin closure time, yet with slightly higher risk of superficial incisional SSI and significantly more postoperative pain. Conflict of interest The authors reported no conflict of interest. All of the authors had substantial contributions to conception, design, acquisition, analysis and interpretation of data. The research was funded by the authors.
References 1. Berghella V, Baxter JK, Chauhan SP (2005) Evidence-based surgery for cesarean delivery. Am J Obstet Gynecol 193:1607–1617 2. Tuuli MG, Rampersad RM, Carbone JF, Stamilio D, Macones GA, Odibo AO (2011) Staples compared with subcuticular suture for skin closure after cesarean delivery. A systematic review and meta-analysis. Obstet Gynecol 117:682 3. Vermillion ST, Lamoutte C, Soper DE, Verdeja A (2000) Wound infection after cesarean. Effect of subcutaneous tissue thickness. Obstet Gynecol 95(6):26–29 4. Tully L, Gates S, Brocklehurst P, McKenzie-McHarg K, Ayers S (2002) Surgical techniques used during caesarean section operations: results of a national survey of practice in the UK. Eur J Obstet Gynecol Reprod Biol 102:120–126 5. Galal I, El-Hindawy K (2011) Impact of using triclosan-antibacterial sutures on incidence of surgical site infection. Am J Surg Aug 202(2):133–138 6. Lucas DN, Yentis SM, Kinsella SM et al (2000) Urgency of caesarean section: a new classification. J R Soc Med 93:346–350
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Arch Gynecol Obstet 7. Chelmow D, Rodriguez EJ, Sabatini MM (2004) Suture closure of subcutaneous fat and wound disruption after cesarean delivery: a meta-analysis. Obstet Gynecol 103(5 Pt 1):974–980 8. Horan TC, Andrus M, Dudeck MA (2008) CDC/NHSN surveillance definition of health care-associated infection and criteria for specific types of infections in the acute care setting. AJIC 36:313–314 9. Fearmonti R, Bond J, Erdmann D, Levinson H (2010) A review of scar scales and scar measuring devices. Eplasty 10:e43 10. Leth RA, Uldbjerg N, Nørgaard M, Møller JK, Thomsen RW (2011) Obesity, diabetes, and the risk of infections diagnosed in hospital and post-discharge infections after cesarean section: a prospective cohort study. Acta Obstet Gynecol Scand 90(5):501–509 11. Altman AD, Allen VM, McNeil SA, Dempster J (2009) Pfannenstiel incision closure: a review of current skin closure techniques. JOGC 31:514–520 12. Clay FS, Walsh CA, Walsh SR (2011) Staples versus subcuticular sutures for skin closure at cesarean delivery: a meta-analysis of randomized controlled trials. Am J Obstet Gynecol 204:378–383
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13. McLean NR, Fyfe AH, Flint EF, Irvine BH, Calvert MH (1980) Comparison of skin closure using continuous and interrupted nylon sutures. Br J Surg 67:633–635 14. Onwuanyi ON, Evbuomwan I (1990) Skin closure during appendectomy: a controlled clinical trial of subcuticular and interrupted transdermal suture techniques. J R Coll Surg Edinb 35:353–355 15. Frishman GN, Schwartz T, Hogan JW (1997) Closure of Pfannenstiel skin incisions. Staples versus subcuticular suture. J Reprod Med 42:627–630 16. Rousseau JA, Girard K, Turcot-Lemay L, Thomas N (2009) A randomized study comparing skin closure in cesarean sections: staples vs subcuticular sutures. Am J Obstet Gynecol Mar 200(3):265e1–265e4 17. Cromi A, Ghezzi F, Gottardi A, Cherubino M, Uccella S, Valdatta L (2010) Cosmetic outcomes of various skin closure methods following cesarean delivery: a randomized trial. Am J Obstet Gynecol 203:285
MATERNAL-FETAL MEDICINE
Superficial incisional surgical site infection rate after cesarean section in obese women: a randomized controlled trial of subcuticular versus interrupted skin suturing Moustafa I. Ibrahim • Gamal Farag Moustafa • Ahmed Sherif Abd Al-Hamid • May Raafat Hussein
Received: 15 November 2012 / Accepted: 14 November 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract Purpose To compare the superficial incisional surgical site infection (SSI) rate after cesarean section (CS) in obese women using subcuticular versus interrupted skin suturing. Methods The current randomized controlled clinical trial was conducted at Ain Shams University Maternity Hospital. Obese non-diabetic women who underwent elective CS were randomized into two groups: group I included women who had their skin closed with interrupted mattress suture using non-absorbable polypropylene, and group II included women who had their skin closed with subcuticular suture using the same suture material. Primary outcome measure was superficial incisional SSI and secondary outcome measures were skin closure time, postoperative pain assessed by ten-point visual analog scale (VAS) and shortterm cosmetic wound outcome according to the Stony Brook Scar Evaluation Scale (SBSES). Results A total of 130 obese women were finally analyzed. Group II (n = 67) was associated with higher incidence of superficial incisional SSI. There were nine cases (13.4 %) compared to three cases (4.8 %) in group I Trial registration: Clinical Trials.gov, NCT01713751. M. I. Ibrahim (&) G. F. Moustafa A. S. A. Al-Hamid M. R. Hussein Department of Obstetrics and Gynecology, Ain Shams University, Building Number 112, El Marwa Tower, Walee EL Ahd Street, Hadayk EL-Kobba, Cairo, Egypt e-mail: [email protected]
(n = 63); however, this difference was statistically not significant (P = 0.088). Skin closure time was significantly prolonged in group I (8.6 ± 2.3 min versus 5.7 ± 2.2 min, respectively, P \ 0.001). Postoperative pain was significantly lower in group I and the mean VAS in group I was 4.7 ± 2 versus 5.5 ± 1.8 in group II (P = 0.017). Using SBSES, group II had mean score 4.5 ± 0.7, while group I had mean score 2.7 ± 1.1. This was statistically significant (P \ 0.001), which means a better cosmetic outcome in group II. Conclusion Subcuticular skin closure during CS for nondiabetic obese women was significantly associated with better short-term cosmetic outcome, less skin closure time, yet, with slightly higher risk of superficial incisional SSI and significantly more postoperative pain. Keywords Surgical site infection Skin closure Cesarean section Abbreviations BMI Body mass index CS Cesarean section SBSES Stony Brook Scar Evaluation Scale SSI Surgical site infection VAS Visual analog scale
G. F. Moustafa e-mail: [email protected]
Introduction
A. S. A. Al-Hamid e-mail: [email protected]
Although several factors contribute to cesarean wound complications, the optimal method of skin closure to minimize these complications is unknown [1]. The two large-scale international trials, CAESAR study and
M. R. Hussein e-mail: [email protected]
123
Arch Gynecol Obstet
CORONIS trial, are underway comparing different techniques of cesarean delivery; however, none evaluates the methods of skin closure [2]. As the incidence of obesity rises, it contributes not only to the increase in cesarean section (CS), but also to post-cesarean wound complications, including infections, seromas, dehiscence and hematomas that are becoming more prevalent [3]. The skin layer can be repaired by subcuticular stitch (immediately below the skin layer), an interrupted stitch (individual stitches) or with skin staples. A survey of skin closure techniques used in the UK showed that the subcuticular skin stitch was the most commonly used (73.9 %) followed by interrupted skin stitch (7.7 %) and others (18.4 %) [4]. Surgical site infection (SSI) is a common complication of surgery. Infection has always been a feature of modern surgery and continues to be a significant problem for health-care practitioners across the world. SSI is a common and major cause of postoperative morbidity. Its morbidities range from delayed healing to systemic sepsis [5]. The aim of the present study was to compare the superficial incisional SSI rate after CS in obese women using subcuticular versus interrupted skin suturing.
Patients and methods The current randomized controlled clinical trial was conducted at Ain Shams University Maternity Hospital, Cairo, Egypt, during the period from March 2012 to August 2012. The study was approved by the Ethical and Research Committee of the Council of Obstetrics and Gynecology Department, Ain Shams University. The study purpose and procedures were explained to all enrolled women and a written informed consent was obtained from each participant. The study included women planned for elective CS. Elective CS is defined as that done at a time to suit the woman and the maternity team [6]. Randomization was done using computer-generated system. The random sequence was printed on identical sheets of paper, put in sealed opaque envelopes and kept with the head nurse of the labor ward. Group assignment was determined preoperatively when the patient fulfilled the study eligibility criteria. Demographic information collected included patient’s age, parity, body mass index (BMI), gestational age at delivery, indication for cesarean section, and medical and surgical histories. Women who had concurrent overt infection (e.g., chorioamnionitis, pyelonephritis or chest infection), intraoperative events that may themselves predispose to perioperative infection (e.g., bowel injury, operative time more than 90 min, major blood loss), hemoglobin less than 10 g/dl, pre-eclampsia, diabetes mellitus or rupture of membranes for more than 12 h, those on immunosuppressive drugs and those who had nonPfannenstiel incision, nonelective cesarean section or BMI
123
\30 kg/m2 were excluded from the study. Our study calculated the BMI of patients from their weight and height at admission, because the BMI at admission was a better indicator of body mass during the at-risk time for development of SSI than the pre-pregnancy BMI. The included women were randomized into one of the following two groups: group I including women who have their skin closed with interrupted mattress stitches using non-absorbable polypropylene ProleneÒ2.0 (Ethicon, Johnson & Johnson Ltd, Aurangabad, Maharashtra, India) and group II including women who had their skin closed with subcuticular stitches using the same suture material. All CS procedures were performed by surgeons who had at least 2 years experience in performing cesarean sections. All the participants were operated under spinal anesthesia. Antibiotic prophylaxis was given, as advised by the local protocols of Ain Shams University Maternity Hospital, as two intravenous doses of broad-spectrum penicillin (after clamping of the umbilical cord and 12 h postoperatively). Oral antibiotic of the same group was then given for 3–5 days. The abdomen was scrubbed starting from the level of the umbilicus till the mid-thigh, using povidone iodine 10 % (BetadineÒ) antiseptic solution. Any scar of previous CS was removed. After closure of the fascial layer, subcutaneous tissue was closed if it was deeper than 2 cm. Patients who needed subcutaneous drain were excluded from the final analysis. The protocol of our hospital is to close the subcutaneous tissue with interrupted stitches using nonabsorbable polyglactin 910 VicrylÒ2.0 (Ethicon, Johnson & Johnson Ltd, Aurangabad, Maharashtra, India). A metaanalysis of three studies including 875 patients authenticated that suture closure of subcutaneous fat during CS resulted in a 34 % decrease in the risk of wound disruption in women with fat thickness [2 cm [7]. Wound was uncovered 24 h postoperatively, and then dressed with alcohol 70 % antiseptic solution for 7 days The wound was inspected after 48 h, 7 days and 1 month after the CS. A superficial incisional SSI must meet the following criteria: infection occurs within 30 days after the operative procedure and involves only the skin and subcutaneous tissue of the incision. A deep incisional SSI means that infection occurs within 30 days after the operative procedure if no implant is left in place or within 1 year if implant is in place, and the infection appears to be related to the operative procedure and involves deep soft tissues (e.g., fascial and muscle layers) of the incision [8]. Pain was measured 48 h after CS using ten-point visual analog scale (VAS) from 0 to 10, with 0 indicating no pain and 10 indicating worst conceivable pain. Short-term cosmetic wound outcome (for 1 month postoperatively) was assessed using the Stony Brook Scar Evaluation Scale (SBSES) [9]. Primary outcome measure was surgical site
Arch Gynecol Obstet Fig. 1 CONSORT 2010 flow diagram
CONSORT 2010 Flow Diagram Enrollment
Assessed for eligibility (n=510)
Excluded (n=370) ♦Not meeting inclusion criteria (n=350) ♦ Declined to participate (n=20)
Randomized (n= 140)
Allocation ♦ Allocated
to interrupted mattress suture group (n=68)
♦ Allocated to subcuticular suture group intervention (n= 72)
Follow -Up ♦ Lost to follow-up (didn't come for follow up visit due to long distance between their residence and our hospital) (n=1)
♦ Lost to follow-up (didn't come for follow up visit due to long distance between their residence and our hospital) (n=1)
Analysis Analysed (n=63) ♦ Excluded from analysis (needed subcutaneous drain) (n=4)
infection during the 1 month study duration, according to the definition devised and adopted by the Centers for Disease Control and Prevention (CDC) [8]. Secondary outcome measures were skin closure time, postoperative pain assessed by ten-point VAS and short-term cosmetic wound outcome using SBSES. This scale is designed to measure the short-term cosmetic outcome of the wound ranging from 0 (the worst) to 5 (the best) [9]. Outcomes were assessed by a neutral investigator who was the first author (Ibrahim M.I.) with 15 years experience in obstetric practice and he played no role in the surgical procedures and/or group allocation.
Sample size justification Sample size was calculated using EpiInfoÒ version 6.0, setting the type-1 error (a) at 0.05 and the power (1-b) at 0.8. Data from a previous study showed that the incidence of post-CS SSI in obese women was 18.4 % [10].Calculation according to these values to give the least statistically acceptable figure produced a minimal sample size of 62 cases in each group. Assuming a dropout rate of 5 %, the minimal sample size was 65 cases in each group.
Analysed (n= 67) ♦ Excluded from analysis (needed subcutaneous drain) (n=4)
Therefore, a minimum of 130 women were to be recruited in the trial, to be randomized into one of the two groups. Statistical analysis The collected data were coded, tabulated and statistically analyzed using the SPSS program (Statistical Package for Social Sciences) software version 18.0. Descriptive statistics were done for numerical parametric data as mean ± SD (standard deviation), while they were done for categorical data as number and percentage. Inferential analyses were done for quantitative variables using independent t test in case of two independent groups with parametric data. Inferential analyses were done for qualitative data using v2 test for independent variables. The significant level was set at 0.05.
Results A total of 140 women were included in the study. The included women were randomly divided into two groups: group I (n = 68) and group II (n = 72). Five patients in
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Arch Gynecol Obstet Table 1 Demographic characteristics of the study groups Group I (N = 63)
Group II (N = 67)
P
30.2 ± 6.0
29.2 ± 3.6
0.273**
Primigravida
3 (4.8 %)
1 (1.5 %)
0.281***
Multigravida
60 (95.2 %)
66 (98.5 %)
Age (years) Parity
BMI (kg/m2)
36.4 ± 5.2
37.5 ± 4.1
0.177**
Gestational age (weeks)
38.5 ± 1.2
38.7 ± 1.2
0.384**
3 (4.5 %)
0.465***
Indications for cesarean section Infertility and bad 6 (9.5 %) obstetric history Repeat CS
52 (82.5 %)
Discussion
52 (77.6 %)
Breech
2 (3.2 %)
5 (7.5 %)
Maternal request
0 (0.0 %)
2 (3.0 %)
Advanced maternal age
2 (3.2 %)
2 (3.0 %)
Non-reassuring fetal condition
1 (1.6 %)
3 (4.5 %)
Values are expressed as mean ± SD, or numbers (%) BMI Body mass index, cs cesarean section ** Analysis using independent t test *** Analysis using Chi-square (v2) test
Table 2 Comparison between both groups regarding surgical site complications Complications
Group I (N = 63)
Group II (N = 67)
P**
Surgical site infection
3 (4.8 %)
9 (13.4 %)
0.088
Serous discharge
5 (7.9 %)
2 (3.0 %)
0.211
Serosanguinous discharge
2 (3.2 %)
0 (0.0 %)
0.142
Bloody discharge
1 (1.6 %)
0 (0.0 %)
0.301
Wound disruption
0 (0.0 %)
2 (3.0 %)
0.167
Problem in stitch removal
3 (4.8 %)
2 (3.0 %)
0.599
Values are expressed as numbers (%) ** Analysis using Chi-square (v2) test
both groups withdrew from the study. So, a total of 130 obese women were finally analyzed. Group I included 63 obese women, while group II included 67 obese women. The flow of women through the study is shown in Fig. 1. The demographic characteristics are shown in Table 1. There were no statistically significant differences between both groups regarding age, parity, BMI, gestational ages at termination and indications for CS in both groups. Skin closure time was significantly prolonged in group I (8.6 ± 2.3 versus 5.7 ± 2.2 min, respectively; P \ 0.001). Comparison between both groups regarding surgical site
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complications is shown in Table 2. No deep incisional SSI was noticed in both groups. Postoperative pain was significantly lower in group I. The mean VAS in group I was 4.7 ± 2 versus 5.5 ± 1.8 in group II (P = 0.017). Using SBSES, group II had a mean score of 4.5 ± 0.7, while group I had a mean score of 2.7 ± 1.1. This was statistically significant (P \ 0.001), which means a better cosmetic outcome in group II.
To our knowledge, no previous studies have addressed the effect of skin closure methods on the incidence of SSI in obese patients who underwent cesarean sections. In our institute, Ain Shams University Maternity Hospital, surgeons usually close the skin of obese women undergoing cesarean sections with non-absorbable interrupted sutures. This may be due to the belief that interrupted sutures allow drainage in addition to the possibility of removal of one or two stitches in the presence of any collection without disruption of the whole wound, as obese women are more prone to wound complication, which will not be possible to perform with the continuous subcuticular technique. On reviewing the literature, we did not find any clear recommendation concerning skin closure in obese women or any high-risk group liable for wound complications. Yet, we identified two systematic reviews and one metaanalysis evaluating skin closure techniques in obstetrics and gynecology. The first review was done by Altman et al. [11] and included five animal and ten human studies: five of which were not related to obstetrics and gynecology. The second review was conducted by Tuuli et al. [2] and included three additional studies which were RCTs, except for one prospective cohort study. Clay et al. [12] included in their meta-analysis the five RCTs that were identified by Tuuli et al. [2]. In this meta-analysis, studies mainly compared the skin closure techniques, whether subcuticular or interrupted, with staples. The five trials randomized 877 women to either technique. Follow-up ranged from 2 weeks to 6 months. The staples group was associated with higher incidence of wound complications (OR 2.12, 95 % CI 1.29–3.48; five trials). Even after exclusion of the study with the highest complication rates, the final analysis was the same. Insufficient data were available to assess postoperative pain or patient satisfaction in this metaanalysis [12]. McLean et al. [13] conducted another RCT to compare subcuticular sutures with interrupted sutures in patients undergoing laparotomy. They concluded that the subcuticular method was quicker and cheaper. Onwuanyi and Evbuomwan [14] compared the subcuticular with interrupted non-absorbable sutures after an uncomplicated appendectomy and found significantly more complications
Arch Gynecol Obstet
such as pain, itching and scar hypertrophy in the interrupted closure group. The overall infection rate (6 %) was evenly distributed in both groups. Their conclusion was that the subcuticular method was safe at any age and offered cost and time-saving advantage. As for our findings, skin closure time was significantly prolonged in interrupted sutures group (P \ 0.001), which agreed with all the previous studies [13, 14]. The subcuticular group was associated with a higher incidence of superficial incisional SSI using the definition of CDC [8]. There were nine (13.4 %) cases in the subcuticular suture group compared to three (4.8 %) in the interrupted suture group; yet this difference was not of statistical significance (P = 0.088). Mclean et al. in their RCT found that infection rates were equally distributed between the two groups; there were two cases in each group representing 3.9 and 3.7 %, respectively [12]. Onwuanyi and Evbuomwan [14] also showed that the infection rates were equally distributed between the two groups (three cases in each group, each containing 50 women). Postoperative pain, assessed by ten-point VAS, was significantly lower in the interrupted sutures group (P = 0.017), which was not assessed by either Mclean et al. [13] or Onwuanyi and Evbuomwan [14]. However, Tuuli et al. [2] in their meta-analysis found that the two closure techniques appeared equivalent in terms of postoperative pain. Using SBSES, the subcuticular group had amean score of 4.5 ± 0.7, while the interrupted group had a mean score of 2.7 ± 1.1; this difference was statistically significant (P \ 0.001). This agreed with the study done by Frishman et al. [15] who found that wound cosmosis (using the categories excellent, good, fair and poor) was superior in patients with subcuticular suture closure compared with staples, as rated by the patients (P = 0.04) and physicians (P = 0.01). This was not in line with McLean et al. [13] where the wound was assessed after 1 month by independent observers and all wounds were considered satisfactory. This might be due to differences in the population, type of operations and incisions. Rousseau et al. [16] and Cromi et al. [17] reported that the staples and subcuticular sutures were equivalent regarding their cosmetic outcome. This might be attributed to the longer duration of follow-up (6 weeks and 6 months respectively). The strengths of our study included randomization design, which disabled all personnel involved in the study from knowing the groups’ allocation. Blinding was not feasible due to the obvious nature of the two techniques; however, bias was relatively controlled through concealment of the
allocation in addition to assessment of the outcomes by a neutral investigator. This is, to our knowledge, the first study that addressed the effect of skin closure methods on the incidence of SSI in obese women undergoing cesarean section. Another strength of this study was selection of obese non-diabetic patients, so as to exclude another risk factor that might predispose to SSI. Using VAS and SBSES for postoperative assessment of pain and wound cosmosis was an additional strengthening point and helped us to compare different methods of skin closure in this group of women. Our study was limited by the short period of follow-up being 1 month; which was attributed to the difficulty in convincing these women to come for visits unless they had wound complications. Another limitation was that the difference between the two groups regarding the rate of superficial incisional SSI was shown to be statistically close to significance (P = 0.088). This may raise a question mark on the power of the study. Observers of the results would assume different (i.e. significant) results if the sample size was bigger. However, the sample size was calculated using a standard sample size calculator (EpiInfoÒ version 6) relying on previously published data [10]. Conclusion Subcuticular skin closure during CS for non-diabetic obese women was significantly associated with better short-term cosmetic outcome and less skin closure time, yet with slightly higher risk of superficial incisional SSI and significantly more postoperative pain. Conflict of interest The authors reported no conflict of interest. All of the authors had substantial contributions to conception, design, acquisition, analysis and interpretation of data. The research was funded by the authors.
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