Modified Serial Techniques “ASTRO” Faciliated Laparoscopic Total Mesorectal Excision for ultralow-Lying Rectal Cancer in Obese Male Patients

Background: Laparoscopic total mesorectal excision (LaTME) is technically challenging for ultralow-lying rectal cancer in obese male patients. Herein, we introduced modified serial techniques “ASTRO” to facilitate LaTME, and the short-term outcomes were presented. Methods A prospective study (NCT05067413) was conducted between December 2020 and January 2022. The modified serial surgical techniques “ASTRO” included 5 key steps: 1) Anterior peritoneal reflection (APR) dissection at the highest line along with a "n"-shaped membrane bridge; 2) Suspending the APR with a purse-string suture through the bladder peritoneum to enlarge the operating space of the anterior rectal wall; 3) Traction and counter-traction continuously of the rectum applied with a cotton tape around the rectum; 4) Resection of the pelvic rectum on tripartition, followed by the sequence of "posterior > anterior > lateral" principle; 5) the trans-anterior Obturator nerve gateway was adapted to transect the distal rectum. The operative data and postoperative short-term outcomes were collected. Results 24 consecutive patients underwent this procedure successfully. The average body mass index (BMI) was 29.9 ± 1.3. The average of tumor height from anal verge was 4.0 cm (range, 3.0–4.5 cm). The median operating time and blood loss was 217 min (range,165–420 min) and 50ml (range,20–100 ml) respectively. The anterior operation space at the midsagittal plane of the pelvis inlet was increased by 2.0 ± 0.3 cm. The calculated dominant angle was 20 ± 3°. The length of stapling line was 6.8 ± 1.0 cm with 11 cases by one cartridge and 13 cases by 2 cartridges. 8 patients developed postoperative complications including 4 with anastomosis leakage (16.7%), 2 with urinary retention (8.3%), one with anastomotic stenosis (4.2%) and one with ileus (4.2%). All the complications were relatively mild and recovered well. Conclusion Modified Serial Techniques “ASTRO” could expand the operating space and facilitate LaTME in obese male patients, thereby reducing the risk of conversion to open and transanal dissection.