Cesarean deliveries comprise more than 25% of deliveries in many industrialized countries and more than 30% of deliveries in the United States.1 Although as many as 1.3 million women undergo this surgery annually in the United States,2 guidance regarding best practices for skin closure is limited.3
Generally, a cesarean delivery is performed through a suprapubic low transverse skin incision. At the end of the operation, the skin incision is typically closed with the placement of either a continuous absorbable suture or interrupted staples that are removed at a later date. A recent survey of U.S. obstetricians showed that the method of closure is chosen based on the preference of the surgeon.4 In our recent randomized trial, we reported that wound complication rates are reduced by 57% in women who undergo suture compared with staple skin closure of cesarean incisions.5
Pain is also an important consideration in choice of skin closure technique. Data in the literature concerning pain associated with suture compared with staple skin closure are varied and limited.6,7 In fact, pain perception at discharge has been assessed in only six randomized controlled trials comparing suture with staples for cesarean skin closure, five of which had fewer than 150 total patients enrolled.6–11 The objective of this secondary analysis of our randomized trial was to compare patient-reported pain and pain medication use associated with suture and staple skin closure after cesarean delivery performed through low transverse skin incisions.
MATERIALS AND METHODS
This study was a prospective, multicenter, randomized clinical trial conducted at three hospitals in the United States: Thomas Jefferson University Hospital in Philadelphia, Pennsylvania; Lankenau Medical Center in Wynnewood, Pennsylvania; and Yale-New Haven Hospital in New Haven, Connecticut. Institutional review board approval was obtained from each hospital. Active enrollment for the study was from 2010 to 2012; the trial was registered on ClinicalTrials.gov (Identifier: NCT01211600). All pregnant women undergoing primary or repeat cesarean delivery at study sites were offered participation and written informed consent was obtained. Women were randomized to closure of the cesarean skin incision with stainless steel staples (to be removed on postoperative days 4–10) or absorbable subcuticular continuous 4-0 suture (poliglecaprone or polyglactin). Because the primary outcome of the study was occurrence of wound complications, we excluded women who may have been at higher risk for a wound complication such as poorly controlled maternal diabetes or cesarean deliveries performed through vertical skin incisions. Details of all exclusion criteria, surgical techniques, randomization, masking, sample size calculation, and primary outcome analysis have been reported elsewhere.5
Prespecified secondary outcomes for this randomized clinical trial included pain medication use and assessment of pain in the immediate postoperative period and at 4–8 weeks after discharge from the hospital.5 As part of routine vital sign assessment postoperatively, patients were asked by nursing staff to rate their pain on a scale from 0 to 10 using a visual graph of facial expressions. Their responses were averaged for analysis at various time points from time of delivery: less than 24 hours, 24–47 hours, 48–72 hours, day of discharge, and for duration of hospital stay. We then calculated the median of these composite measures across patients. We assessed whether pain perception differed in the presence of a wound complication and by number of prior cesarean deliveries.
In addition, patient use of intravenous (IV) and oral narcotics, IV and oral nonsteroidal antiinflammatory drugs, and oral acetaminophen was recorded for the duration of the hospital stay. All narcotics were converted to IV morphine equivalents for the analysis according to The Opioid Calculator.12 We did not modify for incomplete opioid tolerance. Therefore 1 mg IV nalbuphine=1 mg IV morphine; 1 mg IV hydromorphone=6.7 mg IV morphine; 1 mg oral hydromorphone=1.3 mg IV morphine; 1 mg oral hydrocodone or meperidine=0.3 mg IV morphine; 1 mg oral oxycodone=0.5 mg IV morphine; and 1 mg oral codeine=0.1 mg IV morphine. Total acetaminophen dose was calculated by adding up the individual acetaminophen doses for each formulation of acetaminophen the patient received.
At the 6-week postoperative visit, the patient was asked “Is the scar painful?” and asked to rate her discomfort on a scale from 1 to 10, where 1 represents “No, I have no complaints” and 10 represents “Yes, it is the worst imaginable.” For patients who did not come to their postoperative visit, study personnel telephoned the patient to complete the pain assessment.
Categorical variables were summarized using counts and percentages and continuous variables were summarized using medians and interquartile ranges. All participants were analyzed as randomized under the intention-to-treat principle. Randomization arms were compared used χ2 and Fisher's exact tests for categorical variables and Mann-Whitney U and Kruskal-Wallis tests for continuous and ordinal variables. A P value <.05 was considered significant. All analyses were performed using SAS 9.4.
To have 80% power to show a difference of 1 between median pain scores at 4–8 weeks with a score of 1 for suture and 2 for staples using a two-sided Mann-Whitney U test of size 0.05, a sample size of 162 would be required per group. The sample size was calculated using simulation where under the null hypothesis 59% of patients in both arms had scores of 1, 14% score 2, 9% score 3, and smaller percentages at higher values. Thus, under the null hypothesis, both arms had median pain scores of 1. Under the alternative hypothesis, 20% of participants with staples had pain scores increased from 1 to 2 or 3, resulting in 39% score 1, 24% score 2, 19% score 3, and the same smaller percentages as sutures at higher values. Under the alternative hypothesis, the median pain score was 1 in the suture group and 2 in the staples group.
A total of 746 women were randomized: 370 to suture and 376 to staple closure of the cesarean skin incision (Fig. 1). Patient groups were comparable with respect to demographics and pregnancy history (Table 1).
Pain rating and pain medication use were assessed for all patients in the immediate postoperative period. There were no significant differences in pain scores between those who received skin closure with suture and those who received skin closure with staples, regardless of time of assessment postoperatively: less than 24 hours, 24–47 hours, 48–72 hours, on day of discharge, and overall mean pain score in hospital (Table 2). We compared the distribution of pain scores between those with wound complications and those without (Table 2). Although the median pain score was higher for those with wound complications during hospitalization, the differences were small (0.7 points or less) and none of the differences reached statistical significance. At 4–8 weeks, the median pain score was 1 (interquartile range 1, 3) for those without wound complications and 2 (interquartile range 1, 5) for those with wound complications (P=.014). There were significant differences for most in-hospital pain variables by number of prior cesarean deliveries: no prior cesarean deliveries, one prior cesarean delivery, and more than one prior cesarean delivery. In general, those with more than one prior cesarean delivery had greater pain; however, at 6 weeks, the median pain score was 1 in all three groups (P=.459; Table 2).
Fifty percent of patients were discharged on postoperative day 3 and 43% on postoperative day 4. There were no significant differences in the use of narcotics, nonsteroidal antiinflammatory drugs, or acetaminophen between groups during the postcesarean hospitalization (Table 3).
Pain scales were completed by 291 women in the suture group and 298 women in the staple group (79% in each group) at 4–8 weeks postpartum. There were no significant differences in pain reported by patients at their postpartum visit (median time of survey was 45 and 47 days) regardless of whether they received suture or staple closure (Table 4). By the time of the 4–8 weeks postpartum visit, 78% of patients were not using pain medication; approximately 17% were using ibuprofen or acetaminophen, 8% were still using narcotics (including Tylenol #3), and 8% asked for a prescription for additional pain medication (Table 4). There were no significant differences between the groups.
In this secondary analysis of a randomized clinical trial, we observed no significant differences in pain or pain medication use in the postoperative hospitalization or 4–8 weeks postpartum recovery period between women who underwent suturing of their skin incision compared with those who underwent stapling after cesarean delivery.
Our results differ from those of Frishman et al9 who reported higher patient pain scores and more medication use for those closed with staples in a small cohort of women randomized to receive suture (n=25) or staple (n=25) closure after cesarean delivery. Rousseau et al6 studied 101 women undergoing elective term cesarean delivery and reported reduced pain associated with staple closure at the 6-week postpartum visit but not at 1 and 3 days after delivery. More recent data from five randomized controlled trials, which varied in enrollment size from 59 to 398, reported no differences in pain perception (visual analog scale, 0–10 scale, numeric rating scale, or author-developed scale) between suture and staple closure,7,8,10,13,14 consistent with a meta-analysis of pain at discharge among women who underwent cesarean delivery.4
Strengths of this study include its multicenter nature, patient diversity regarding demographic characteristics, and adequate large sample size. Additionally, our assessment of medication use provides a measure of patient pain that objectively validates the subjective patient-reported data in the immediate and 4–8 weeks postpartum period. Our sample size almost doubles the data from all six prior randomized studies published on pain perception between sutures and staples for cesarean delivery skin closure.6–11
This study was limited by our ability to contact all patients for the postdischarge follow-up pain assessments: these data were available for 291 women (79%) who received suture closure and 298 women (79%) who received staple closure.
This limitation aside, taken together with the primary outcome data from our trial in which suture closure lowered the rate of wound complications,5 data from this secondary analysis give further support for the use of suture closure, which neither increases pain nor pain medication use.
1. Declercq E, Young R, Cabral H, Ecker J. Is a rising cesarean delivery rate inevitable? Trends in industrialized countries, 1987 to 2007. Birth 2011;38:99–104.
2. Martin JA, Hamilton BE, Ventura SJ, Osterman MJK, Wilson EC, Mathews TJ. Births: final data for 2010. Natl Vital Stat Rep 2012;61:1–72.
3. Mackeen AD, Berghella V, Larsen ML. Techniques and materials for skin closure in caesarean section. Cochrane Database of Systematic Reviews 2012, Issue 11. Art. No.: CD003577. DOI: 10.1002/14651858.CD003577.pub3.
4. Mackeen AD, Schuster M, Berghella V. Suture versus staples for skin closure after cesarean: a meta-analysis. Am J Obstet Gynecol 2015;212:621.e1–10.
5. Mackeen AD, Khalifeh K, Fleisher J, Vogell A, Han C, Sendecki J, et al.; CROSS Consortium. Suture compared with staple skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol 2014;123:1169–75.
6. Rousseau JA, Girard K, Turcot-Lemay L, Thomas N. A randomized study comparing skin closure in cesarean sections: staples vs subcuticular sutures. Am J Obstet Gynecol 2009;200:265.e1–4.
7. Sharma C, Verma A, Soni A, Thusoo M, Mahajan VK, Verma S. A randomized controlled trial comparing cosmetic outcome after skin closure with ‘staples’ or ‘subcuticular sutures’ in emergency cesarean section. Arch Gynecol Obstet 2014;290:655–9.
8. Figueroa D, Jauk VC, Szychowski JM, Garner R, Biggio JR, Andrews WW, et al.. Surgical staples compared with subcuticular suture for skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol 2013;121:33–8.
9. Frishman GN, Schwartz T, Hogan JW. Closure of Pfannenstiel skin incisions. Staples vs. subcuticular suture. J Reprod Med 1997;42:627–30.
10. Huppelschoten AG, van Ginderen JC, van den Broek KC, Bouwma AE, Oosterbaan HP. Different ways of subcutaneous tissue and skin closure at cesarean section: a randomized clinical trial on the long-term cosmetic outcome. Acta Obstet Gynecol Scand 2013;92:916–24.
11. de Graaf I, Rengerink KO, Wiersma IC, Donker M, Mol BW, Pajkrt E. Techniques for wound closure at caesarean section: a randomized clinical trial. Eur J Obstet Gynecol Reprod Biol 2012;165:47–52.
13. Aabakke AJ, Krebs L, Pipper CB, Secher NJ. Subcuticular suture compared with staples for skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol 2013;122:878–84.
© 2015 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
14. Gaertner E, Burkhardt T, Beinder E. Scar appearance of different skin and subcutaneous tissue closure techniques in caesarean section: a randomized study. Eur J Obstet Gynecol 2008;138:29–33.