“Dog ear” formation after double-stapled low anterior resection as a risk factor for anastomotic disruption

Despite improvement in surgical techniques and stapling devices during the last 10 years, colorectal anastomoses are still prone to leakage. The purpose of this study was to assess the performance and safety of stapled anastomoses in rectal surgery and to identify factors that influence the occurrence of anastomotic leaks. A review was undertaken of 1,014 patients who underwent stapled anastomoses to the rectum or anal canal for colorectal cancer or benign disease between 1989 and 1995 in a tertiary care institution. Indications for operations, comorbidities at admission, preoperative bowel preparation, stapler size, intraoperative events, associated surgical procedures, and clinical outcomes were tested for any association with anastomotic leak. A double stapled technique was used in 154 patients and a conventional single stapler technique was used in 860. Postoperative mortality was 1.6%, and the overall morbidity was 18.4%. Clinically apparent anastomotic leak developed in 29 patients (2.9%). Anastomotic dehiscence occurred in 22 of 284 patients (7.7%) after low stapling (within 7 cm from the anal verge) and in 7 of 730 patients (1%) after high stapling (p < 0.001). Diabetes mellitus, use of pelvic drainage, and duration of surgery were significantly related to the occurrence of anastomotic leak by the univariate analysis. Multivariate regression analysis identified an anastomotic distance from the anal verge within 7 cm as the only variable related to the occurrence of postoperative leak (p < 0.001). Low anastomoses were associated with a leak rate greater than with high colorectal anastomoses. We conclude that anastomoses to the rectum using the circular stapler can be done with low mortality and morbidity.

A stapling instrument is described for end-to-end inverting anastomoses applicable principally to low rectal anastomosis or esophagogastric or esophagojejunal anastomosis. The instrument creates an inverting anastomosis held by a double staggered row of stainless steel wire staples creating an anastomosis 21.2 mm internal diameter with no significant inverted flange. The early experience is encouraging.

Anastomotic leaks after double-stapled low anterior resection were associated with a number of factors related to patient condition, level of anastomosis, and variety of surgery-related and antitumor therapy-related factors. This retrospective analysis of a group of patients with consistent length of rectal stump was undertaken to determine the risk factors of anastomotic leak after low colorectal resection related to surgery and to intraperitoneal chemotherapy. A group of 165 patients treated with surgery only, surgery with early postoperative intraperitoneal chemotherapy, and surgery with hyperthermic intraoperative and early postoperative intraperitoneal chemotherapy. All patients underwent surgery that used the double-stapled technique with transection of the rectum through its middle third. In univariate and multivariate analysis, the relationship between anastomotic leak rate and extent of colon resection, length of residual colon, presence of left colon, and type of applied treatment was studied. With a full length of residual colon, leak rate was 1 percent but increased progressively with the extent of proximal colon resection. Removal of the left colon was associated with the 2.7 odds ratio for anastomotic disruption. Leak rate after surgery only was 6 percent; surgery with normothermic intraperitoneal chemotherapy was 5 percent; and surgery with heated intraperitoneal chemotherapy was 20 percent. In this group of patients with consistent length of residual rectum, the incidence of anastomotic disruption was related to extent of proximal colon resection. Anastomotic integrity was not compromised by normothermic intraperitoneal chemotherapy. Hyperthermic intraperitoneal chemotherapy was associated with high leak rate only when extensive resection of the colon was performed. Variables other than extent of rectal excision are important in causing a leak of colorectal anastomosis.