Rectal stenosis after circular mechanical anastomosis; the influence of stapler size

Background: The incidence of benign anastomotic stenosis (BAS) after radical surgery for rectal cancer ranges from 2 to 30%. There are few data regarding the factors related to its occurrence. One of these factors is the diameter of the circular mechanical staplers (CMS) used. Methods: Observational study with prospective data recording of consecutive patients with non-disseminated rectal cancer operated on at two hospitals with special dedication to rectal cancer. Patients underwent low anterior resection (LAR) of the rectum with colorectal anastomosis created using CMS of diameters of either 28-29 or 31-33 mm. The primary endpoint was BAS. Secondary variables were demographic and patient-dependent data, and preoperative, intraoperative, immediate postoperative and mid-term data. The incidence of BAS was compared in the groups in which the different stapler diameters were used. Results: Between 2012 and 2022, 239 patients were included. BAS was recorded in 39 (16.3%). In the analysis of factors related to its occurrence, the only significant variable was stapler diameter (p = 0.002, 95% CI 7.27-23.53), since rates of BAS were lower in the 31-33 mm group. Similarly, in the logistic regression analysis, stapler size was not associated with postoperative complications or anastomotic dehiscence (OR 3.5, 95% CI 1.2-10.5). Comparing stapler groups, BAS was detected in 35 of 165 patients (21%) in the 28-29 mm group but in only four out of 74 (5.6%) in the 31-33 mm group (p = 0.002, 95% CI 7.27-23.53). Ileostomy closure took longer and was less frequent in the 28-29 mm group. Conclusions: The rate of BAS after LAR was not negligible, since it was recorded in 39 of 239 patients (16.3%). The use of a 31-33 mm CMS was associated with a lower incidence of BAS. Therefore, the use of larger staplers is tentatively recommended; however, clinical trials are now required to confirm these results. Graphical abstract: (Figure presented.)