Effect of insufflation pressure during transanal minimally invasive surgery on surgical complications with dissection of the rectal submucosa in canine cadavers.

OBJECTIVE: To determine ideal insufflation pressures during transanal minimally invasive surgery (TAMIS) in canine cadavers for rectal submucosal transection and incisional closure. ANIMALS: 16 canine cadavers. PROCEDURES: Cadavers were placed in lateral recumbency. Urinary catheters were placed to measure intra-abdominal pressure (IAP). A single access port was placed to establish a pneumorectum. Cadavers were placed in insufflation groups of 6 mmHg to 8 mmHg (group 1), 10 mmHg to 12 mmHg (group 2), or 14 mmHg to 16 mmHg (group 3). Defects in the rectal submucosa were created and closed with a unidirectional barbed suture. Duration for each procedure and subjective ease of identifying the transection plane and performing incisional closure were assessed. RESULTS: The single access port was successfully placed in dogs weighing 22.7 kg to 48 kg. The ease of each step of the procedure was not influenced by the insufflation pressure. The median surgical duration for group 1 was 740 seconds (range = 564 to 951 seconds), 879 seconds (range = 678 to 991 seconds) for group 2, and 749 seconds (range = 630 to 1,244 seconds) for group 3 (P = .650). The insufflation pressure increased the IAP (P = .007). Perforation of the rectum happened in 2 cadavers in group 3. CLINICAL RELEVANCE: The duration of each step of the procedure was not significantly influenced by insufflation pressure. Defining the dissection plane and performing resection was more challenging in the highest-pressure group. Rectal perforation occurred only with the 14 mmHg to 16 mmHg insufflation pressure. Single access port usage with TAMIS may provide a readily available, minimally invasive approach for the resection of rectal tumors in dogs.

Evaluation of transanal minimally invasive surgery for submucosal rectal resection in cadaveric canine specimens.

OBJECTIVE: To evaluate the feasibility of transanal minimally invasive surgery (TAMIS) for submucosal rectal resection in large breed dogs. STUDY DESIGN: Cadaveric study. SAMPLE POPULATION: Canine cadavers (n = 6) weighing between 37.5 and 60 kg. METHODS: Dogs were positioned in sternal recumbency. After rectal cleansing, a transanal access platform was placed in the rectum, and a pneumorectum was established. An area of ventral rectal wall approximately 2 × 2 cm was resected in a submucosal plane by using laparoscopic instruments and submitted for histopathological evaluation. The rectal wall defect was closed with a single-layer continuous suture pattern with barbed suture. Postoperatively, the rectum was removed en bloc and evaluated for suture or surgical penetration of the serosal surface. RESULTS: Submucosal rectal resection was successfully completed by using TAMIS in all dogs. The median length of resected specimens after fixation was 24.5 mm (range 9.8-26.5). In two of six dogs, suture was macroscopically visible on the serosal surface, but no dogs had evidence of iatrogenic full-thickness surgical penetration of the rectum. The median distance from the aborad extent of the suture closure line to the anocutaneous junction was 35 mm (range, 35-105). CONCLUSION: Submucosal resection of the canine rectal wall was feasible in large breed dogs by using TAMIS. No evidence of full-thickness penetration of the rectal wall was seen in these cadaveric specimens. CLINICAL SIGNIFICANCE: Transanal minimally invasive surgery may provide an alternative minimally invasive approach for resection for benign adenomatous rectal polyps in large breed dogs that might otherwise require a rectal pull-through.