Recently published randomized trials examining skin closure technique on postcesarean wound complications have produced conflicting results. We performed a metaanalysis of trials comparing staples and subcuticular sutures for skin closure at cesarean section (CS). Pooled outcome measures were calculated using random effects models. Primary outcomes were rates of wound dehiscence (separation) and a composite wound complication rate. Secondary outcomes were patient satisfaction, operating time, and postoperative pain. A total of 877 women from 5 trials were included. Both wound separation (pooled odds ratio, 4.01; P < .0001) and composite wound complication (pooled odds ratio, 2.11; P = .003) rates were higher with staples. The use of staples reduced operating time (weighted mean difference, –5.05 minutes; P = .021). Data on postoperative pain and patient satisfaction were insufficient for metaanalysis. Our findings suggest a possible benefit with subcuticular sutures compared to skin staples for skin closure at CS. However, the optimal skin closure technique at CS demands further study.
The cesarean section (CS) was first described in Roman times but only at the start of the 20th century did it begin to offer acceptable morbidity and mortality for both mother and baby. It is now one of the most common surgical procedures performed globally and CS rates continue to increase. In England, for instance, 25% of all babies in 2009 were born via the abdominal route, compared to 19% 10 years previously. Similar rates are evident in the United States (31% in 2006). Over the past 50 years, evidence-based refinements have been made to surgical practice at CS, but there still remain many areas of contention regarding the optimal operative technique.
Wound complications are a major source of morbidity after CS and contribute to prolonged hospital stay and rates of readmission. Age, body mass index (BMI), length of incision, and timing of prophylactic antibiotic administration have all been associated with postcesarean surgical site infection (SSI). Duration of membrane rupture, a risk factor unique to the pregnant patient, also impacts on infection-related morbidity. However, the role of skin closure technique on wound complication rates in obstetrics is poorly studied.
Despite the recent emergence of tissue adhesives for wound closure, the principal debate surrounding skin closure at CS has been between skin staples and subcuticular (intracutaneous) sutures. This issue has been extensively studied in other surgical specialties but until very recently, there were limited data on which to base recommendations for CS. A 2008 Cochrane review identified only 1 small randomized trial on this issue with insufficient numbers on which to base any recommendations. Since then, several randomized trials addressing this issue have been published with conflicting conclusions. Although some studies have found no difference in wound outcomes by closure technique, others have shown staples to be the superior choice. In contrast, other randomized studies have concluded that sutures are the preferred closure material creating genuine clinical equipoise in this area. We present a metaanalysis of randomized controlled trials (RCT) examining skin closure technique at CS to provide practitioners with an evidence base for choosing the correct closure method for this common surgical procedure.
Materials and methods
This metaanalysis was conducted according to recommendations of the PRISMA statement. The PubMed, MEDLINE, and Cochrane Databases were searched in September 2010 for English-language articles without time restrictions. Combinations of the search terms “c(a)esarean,” “skin,” “closure,” “staples,” “sutures,” “randomis(z)ed,” and “technique” were used to identify eligible studies. This search was performed independently by 2 authors (F.S.H.C. and C.A.W.). Abstracts of the publications identified by the primary search were reviewed. In addition, online trial registries ( www.controlled-trials.com and www.clinicaltrials.gov ) were searched for eligible studies. Finally, abstracts from the annual meetings of the Society for Maternal-Fetal Medicine (SMFM), 2001 through 2009, were searched for suitable studies ( www.ajog.org/content/SMFM_supplements ).
Study selection
Only prospective, randomized trials were included in the analysis. Studies were considered eligible if they reported outcome data by method of skin closure at CS with at least 1 clinical endpoint relevant to the present analysis. Studies comparing sutures or staples with other closure techniques were excluded. Review articles and retrospective studies were excluded from the analysis.
Methodological quality of included studies
Studies meeting inclusion criteria were assessed for quality using the scoring system of Jadad et al. This system assigns scores for randomization, double blinding, and reporting of dropouts and exclusions. The overall scores range from minimum 0 to maximum 5.
Study outcomes
The primary outcome of the present analysis was incidence of wound separation (dehiscence) and a composite wound complication rate (including dehiscence, wound infection, seroma and hematoma requiring surgical intervention). Secondary outcomes were patient satisfaction rates, operating time, and postoperative pain scores.
Statistical analysis
Data were abstracted into a computerized spreadsheet (Microsoft Office Excel 2007; Microsoft, Redmond, WA) for analysis. Pooled odds ratios (OR) were calculated for categorical variables and the weighted mean difference was determined for continuous variables. These pooled outcome measures were calculated using random effects models as per Der-Simonian and Laird. Where possible, data were analyzed on an intention-to-treat basis. Heterogeneity was assessed using Cochran Q-test, a negative hypothesis test in which a P value <5% indicates the presence of significant statistical heterogeneity. Bias was assessed visually by inspection of a funnel plot and statistically by use of the Horbold-Egger test. The 5% level was considered significant. The statistical analysis was performed using Statsdirect 2·5·7 (Statsdirect Ltd, Altrincham, UK).
Results
The primary search returned 288 studies with potential for inclusion. These abstracts were screened for randomized trials only, yielding 27 studies. On further review, 17 of these RCT did not pertain to skin closure techniques. The remaining 10 citations–6 published studies and 4 abstracts–were analyzed in detail and their references screened for further eligible citations. Two studies were not direct comparisons between skin staples and subcuticular sutures and were excluded from further analysis. All 4 SMFM abstracts were subsequently published as full peer-reviewed papers and were excluded to avoid duplication. One further eligible RCT was identified from the reference lists. As such, 5 RCTs of skin closure techniques at CS were included in the metaanalysis. Using the Jadad score to assess study quality, all 5 trials were of moderate quality (Jadad score 2/5 or 3/5).
These 5 trials randomized 877 women (492 to subcuticular sutures, 385 to skin staples) ( Table 1 ). Data were analyzed on an intention-to-treat basis. A composite wound complication rate was reported by all 5 trials. Overall, patients receiving staples experienced more wound complications (50/385 vs 28/492; pooled OR, 2.11; 95% confidence interval [CI], 1.29–3.48; P = .003) ( Table 2 and Figure 1 ). There was no evidence of heterogeneity (Cochran Q, 3.29; P = .51) or bias (Horbold-Egger, –0.71; P = .37). The study by Basha et al, reported high wound complication rates compared to the remaining studies. Therefore, a sensitivity analysis was performed, excluding data from this study. This revealed no difference in composite wound complication rates between the 2 groups (pooled OR, 1.05; 95% CI, 0.38–2.93; P = .93).
| Variable | Frishman et al, 1997 | Gaertner et al, 2008 | Rousseau et al, 2009 | Cromi et al, 2010 | Basha et al, 2010 |
|---|---|---|---|---|---|
| n | 66 | 100 | 101 | 180 | 430 |
| Wound closure method | |||||
| Subcuticular sutures | 32 | 49 | 52 | 135 | 224 |
| Skin staples | 34 | 51 | 49 | 45 | 206 |
| Suture material | 4/0 polyglycolic acid | 3/0 polyglactin | 2/0 Monocryl | 3/0 mixed | 4/0 Monocryl |
| Surgeons | Junior resident | N/A | Residents | Attending and senior residents | Attending and residents |
| Antibiotic prophylaxis | N/A | 100% | N/A | N/A | 99% |
| BMI, kg/m 2 | N/A | N/A | ≤35 | N/A | Range |
| Subcutaneous closure | N/A | 50/50 | 100% | If ≥2 cm | If ≥2 cm |
| Staple removal | Discharge | Day 6 | Day 3 | Day 7 | Day 3-4 |
| Postoperative pain assessment | VAS | N/A | VAS | N/A | N/A |
| Follow-up | 6 wk | 4 mo | 6 wk | 2 and 6 mo | 2-4 wk |
| Wound assessment | Subjective | Nonvalidated scale | Scar evaluation scale | Objective assessment scales | Telephone interview |
| Patient satisfaction | Subjective categories | Nonvalidated scale | VAS | VAS | Telephone interview |
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