The legendary superior strength of the Pfannenstiel incision: a myth?

OBJECTIVE: This study was undertaken to determine whether there is a difference in the frequency of fascial dehiscence between midline vertical lower abdominal and Pfannenstiel incisions among women undergoing obstetric and gynecologic operations.

STUDY DESIGN: A case-control study of 48 cases of fascial dehiscence complicating 17, 995 major operations (8950 cesarean deliveries and 9405 gynecologic procedures) during a 6-year period at Wayne State University Hutzel Hospital, Detroit, was performed. Univariate analysis identified significant independent variables related to fascial dehiscence. Stepwise logistic regression analysis then identified those risk factors that were independently associated with fascial dehiscence.

RESULTS: Among the 48 patients who underwent repair of fascial dehiscence after a major obstetric or gynecologic operation, 27 were from the obstetric service and 21 were from the benign and cancer gynecologic services. Wound dehiscence occurred in 10 vertical incisions and 17 Pfannenstiel incisions among the obstetric patients and in 12 vertical and 9 Pfannenstiel incisions among the gynecologic patients. The risk for dehiscence with vertical lower abdominal incisions was not increased with respect to that associated with Pfannenstiel incisions (P =.39, 2-tailed). This finding was true for all patients (odds ratio, 1.3; 95% confidence interval, 0.7-2.6), obstetric patients (odds ratio, 1.3; 95% confidence interval, 0.5-3.4), and gynecologic patients (odds ratio, 1.5; 95% confidence interval, 0.5-4.0). Forty-seven of the 48 case patients had documented wound infections, compared with 1 of the 144 control subjects (P <.0001, odds ratio, 37.8; 95% confidence interval, 14.8-96.8).

CONCLUSION: Wound infection was the most important risk factor for fascial dehiscence among women who underwent major obstetric and gynecologic operations. Our results do not support the long-held belief that Pfannenstiel incisions are stronger than lower abdominal vertical incisions and reduce the risk for fascial dehiscence.