Objective
The objective of the study was to compare scar quality associated with different types of wound closure methods after cesarean section (CS).
Study Design
Patients were randomized to have skin closure following CS with either staples or 3 different types of subcuticular sutures. Scar quality was evaluated 2 and 6 months postoperatively. The Vancouver Scar Scale, the Patient and Observer Scar Assessment Scale (POSAS), and a visual analog scale were used as scar assessment tools.
Results
Of the 180 patients who were recruited, 123 successfully completed the study. No difference in both subjective and objective scar rating was detected across groups at either 2 months or 6 months. In the overall study population, objective scores correlated with patient rating, and correlation was strongest between the observer and patient components of the POSAS (r = 0.48).
Conclusion
In women undergoing CS, stapled wounds and those closed with subcuticular sutures result in equivalent cosmetic appearance of the scar.
Every year several million women worldwide acquire an abdominal scar as result of a cesarean delivery. Obstetricians often consider skin closure after a cesarean section as a trivial aspect of the procedure, because the skin scar is deemed the normal and inevitable price we pay for tissue repair. Moreover, the anatomical location of cesarean scars, which hide easily beneath underwear, and the generally held belief that all transverse suprapubic incisions heal about equally well further contribute to the underestimation by practitioners of the importance of scar appearance to patients.
Young women place supreme importance on cosmetic outcomes, but scarring can also affect patients in terms of symptoms (pain, tenderness, and itching) and has the potential to have a negative impact on overall quality of life, being a source of considerable distress, loss of self-esteem, and stigmatization.
The final appearance and function of the healed skin is dependent on patient and wound factors, which are often outside the control of a surgeon, and technical factors, which are completely within the control of the surgeon and include closure material and technique of skin apposition. Methods of skin closure after cesarean delivery vary widely between obstetricians and are largely the result of surgeon’s personal choice.
Despite increasing emphasis on evidence-based practice, there are few reliable comparative data on which to base closure method selection. There are exceedingly few clinical trials specifically comparing the healing outcomes associated with different closure techniques, and most suffer from poor methodology, including lack of rater’s blindness to treatment assignment, use of the authors’ own assessment scales, and follow-up time too short for proper evaluation of the final appearance of the scars.
In an attempt to provide obstetricians with evidence-based guidance for the choice of suture technique after cesarean delivery, we designed a randomized trial aimed to compare scar quality associated with different types of wound closure methods, using standardized and validated assessment tools that incorporate both observer and patient scar ratings.
Materials and Methods
A single-institution, randomized, multidisciplinary clinical trial was designed to compare healing outcomes of Pfannenstiel incision after cesarean delivery using different skin closure methods. Between October 2006–March 2008, women undergoing cesarean section for any indication who were at least 18 years old and literate in Italian language were offered participation in the study.
Exclusion criteria included history of keloids, previous transversal suprapubic scars, tattoos in the area to be studied, known patient hypersensitivity to any of the suture materials used in the protocol, and a medical disorder that could affect wound healing (eg, diabetes mellitus, severe malnutrition because of anorexia nervosa, disorders requiring chronic corticosteroid use).
Consenting patients were randomized to have skin closure of their cesarean section wound with either staples (disposable Weck Visistat stapler; Telefex Medical, Research Triangle Park, NC) or subcuticular running suture selected among 1 of the following 3 options, each of which entailed the use of a 3.0-caliber suture: (1) a midterm absorbable monofilament suture (Monosyn; B Brown, Aesculap, Tuttlingen, Germany); (2) a nonabsorbable monofilament suture made of polyamide polymers (Dafilon; B Brown); or (3) a short-term synthetic absorbable braided and coated suture made of low-molecular-weight polyglycolic acid (Safil Quick; B Brown).
Each patient was enrolled prior to the initiation of surgery and provided written informed consent to participate in this Research Ethics Board-approved study. All patients scheduled for an elective procedure were enrolled on admission on the morning of the procedure, whereas in case of cesarean delivery performed for emergency indications, participants were enrolled at the time that the decision to perform the procedure was made. Allocation to 1 of the 4 closure methods was on 1:1 basis using a block-randomized computer-generated list. All participating surgeons were either attending obstetricians or senior residents and operated on patients in all skin closure groups.
A proportion of patients enrolled in the current study was included in a previous report from the study institution, addressing the method of expanding the uterine incision (blunt extension by separating the fingers in a transversal vs cephalad-caudad direction) at the time of cesarean delivery. With this only exception, the surgical steps up to the point of skin closure were accomplished in a standard fashion. Suture closure of subcutaneous fat was performed only in women with subcutaneous thickness of 2 cm or greater. The staples and nonabsorbable sutures were removed on the seventh postoperative day.
Follow-up included an initial appointment 8 weeks postoperatively, at which time initial healing results were evaluated and additional data regarding wound infection and any other adverse wound events were recorded. The cosmetic outcome of patient scars was assessed for a second time at 6 months after surgery. At each time point, the standardized scar assessment comprised the following: (1) classification of the scar using the categorization proposed by the International Advisory Panel on Scar Management; (2) objective scar rating using the Vancouver Scar Scale (VSS) and the observer component of the Patient and Observer Scar Assessment Scale (POSAS); (3) subjective scar rating using the patient component of the POSAS and a visual analog scale (VAS). A single observer, a plastic surgeon trained in the use of scar assessment scales, who was blinded to the method of skin closure, performed objective scar analysis.
Scars were categorized as mature (a light-colored, flat scar), immature (a red, sometimes itchy or painful, and slightly elevated scar in the process of remodeling), linear hypertrophic (a red, raised, sometimes itchy scar confined to the border of the original surgical incision), minor keloid (a focally raised, itchy scar extending over normal tissue), and major keloid (a large, raised scar greater than 0.5 cm, possibly painful or pruritic, and extending over normal tissue) ( Figure 1 ).
The Vancouver scale rated 4 physical characteristics of scars: vascularity, pigmentation, pliability, and height. Each variable contained ranked subscales that may be summed to obtain a total score ranging from 0–13, with 0 representing normal skin ( Table 1 ). The lower the score, the more the scar resembled normal tissue. The Observer Scar Assessment Scale (OSAS) rated 5 variables: vascularity, pigmentation, thickness, relief, and pliability. Each variable used a 10-point scoring system, with 1 representing normal skin. Ratings of individual variables may be summed to obtain a total score ranging from 5–50, with 5 representing normal skin ( Figure 2 ).
| Scar characteristic | Score |
|---|---|
| Vascularity | |
| Normal | 0 |
| Pink | 1 |
| Red | 2 |
| Purple | 3 |
| Pigmentation | |
| Normal | 0 |
| Hypopigmentation | 1 |
| Hyperpigmentation | 2 |
| Pliability | |
| Normal | 0 |
| Supple | 1 |
| Yielding | 2 |
| Firm | 3 |
| Ropes | 4 |
| Contracture | 5 |
| Height | |
| Flat | 0 |
| <2 mm | 1 |
| 2–5 mm | 2 |
| >5 mm | 3 |
All patients, blinded to the observers’ scar rating, were asked to provide ratings of their scars using the patient component of the POSAS on the same day as the observers. The Patient Scar Assessment Scale (PSAS) consisted of 6 items on scar-related pain, itchiness, color, stiffness, thickness, and irregularity. Each item used a 10-point scoring system, summed to obtain a total score ranging from 6–60, with 6 representing normal skin with no associated symptoms. After these domains were scored, the patients were asked to rate their overall satisfaction with the appearance of their scars using a 10-point VAS, with 0 representing the worst and 10 the best expected appearance of their scars.
The primary outcome measure was POSAS summary score (PSAS and OSAS components) at 6 months postoperatively. Secondary outcome measures included VSS summary score and overall patient satisfaction assessed by a VAS.
At the time of study design, we carried out a systematic literature search in PubMed to identify studies of abdominal incision skin closure, and we were unable to find previously published data that we could use to make a reasonable assumption of the true effect size. Likewise, an estimate of the magnitude of cosmetic improvement for which patients would consider a change in treatment to be worthwhile was unavailable in the literature. Therefore, we performed a power analysis based entirely on a logical and realistic assessment of what could constitute a clinically important effect when evaluating surgical scar cosmesis.
We judged that it would make sense to set the clinically significant effect at a medium level of effect size. Sample size was calculated using a fixed-effects single factor design of F test (analysis of variance [ANOVA]) in G*Power 3 software. Assuming α = 0.05, the probability of a β error = 0.20, and an effect size index F = 0.30, a sample size of 32 cases in each arm was found to be required. To account for an attrition rate of up to 40%, 45 patients were enrolled in each arm of the study protocol.
Statistical analysis of healing outcomes data was performed with GraphPad version 5 (GraphPad Software, San Diego, CA). Normality testing (D’Agostino and Pearson test) was performed to determine whether data were sampled from a Gaussian distribution. One-way ANOVA and a Kruskal-Wallis test were performed to compare groups of continuous parametric and nonparametric variables, respectively. A χ 2 test was used to analyze proportions. Secondary endpoints were to test convergent validity (agreement among independently gathered ratings) and to assess changes in scar rating over time. For these purposes, Sperman’s rho correlation and the Wilcoxon matched pairs test were used. A P < .05 was used as the cutpoint for significance.
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