Narrow pelvic inlet plane area and obesity as risk factors for anastomotic leakage after intersphincteric resection

BACKGROUND: Intersphincteric resection (ISR) has been increasingly used as the ultimate sphincter-preserving procedure in extremely low rectal cancer. The most critical complication of this technique is anastomotic leakage. The incidence rate of anastomotic leakage after ISR has been reported to range from 5.1% to 20%. AIM: To investigate risk factors for anastomotic leakage after ISR based on clinicopathological variables and pelvimetry. METHODS: This study was conducted at Department of Colorectal Surgery, Japanese Red Cross Medical Center, Tokyo, Japan, with a total of 117 patients. We enrolled 117 patients with extremely low rectal cancer who underwent laparotomic and laparoscopic ISRs at our hospital. We conducted retrospective univariate and multivariate regression analyses on 33 items to elucidate the risk factors for anastomotic leakage after ISR. Pelvic dimensions were measured using three-dimensional reconstruction of computed tomography images. The optimal cutoff value of the pelvic inlet plane area that predicts anastomotic leakage was determined using a receiver operating characteristic (ROC) curve. RESULTS: We observed anastomotic leakage in 10 (8.5%) of the 117 patients. In the multivariate analysis, we identified high body mass index (odds ratio 1.674; 95% confidence interval: 1.087-2.58; P = 0.019) and smaller pelvic inlet plane area (odds ratio 0.998; 95% confidence interval: 0.997-0.999; P = 0.012) as statistically significant risk factors for anastomotic leakage. According to the receiver operating characteristic curves, the optimal cutoff value of the pelvic inlet plane area was 10074 mm(2). Narrow pelvic inlet plane area (≤ 10074 mm(2)) predicted anastomotic leakage with a sensitivity of 90%, a specificity of 85.9%, and an accuracy of 86.3%. CONCLUSION: Narrow pelvic inlet and obesity were independent risk factors for anastomotic leakage after ISR. Anastomotic leakage after ISR may be predicted from a narrow pelvic inlet plane area (≤ 10074 mm(2)).