Compression injury of the circular stapler for gastrointestinal end-to-end anastomosis: preliminary in-vitro study

The impact of powered circular staplers on anastomotic leak in left-sided colorectal cancer surgeries

BACKGROUND

Since the introduction of powered circular staplers in colorectal surgery, there has been growing interest in their impact on reducing complications, particularly anastomotic leakage. This study compared short-term postoperative outcomes between powered and manual circular staplers.

METHODS

This retrospective study included colorectal cancer patients at the tertiary referral center from April to October 2023 who underwent anterior or low anterior resection (LAR) using a circular stapler. According to energy source, patients were divided into powered and manual groups, which used two powered and four types of manual staplers, respectively. All open, laparoscopic, and robotic approaches were included. Propensity score matching (PSM) analysis was used to reduce selection bias. Postoperative complications within 30 days, especially for anastomosis-related complications, were compared between the groups.

RESULTS

Among 511 patients, the powered group was 161 (32%). After PSM, 143 pairs of 286 patients were analyzed. The proportions of LAR were 53.8% and 51.0%, and initial diverting stoma rates were 23.1% and 22.4% for the Powered and Manual groups, respectively. Comprehensive complication rates were similar between the Powered group and the Manual group, without statistical significance (13.3% vs. 21.0%, P = 0.063). Anastomotic leakage was not different between the Powered and Manual groups (4.2% vs. 4.9%, P = 0.782). There was no significant difference in other complications, including anastomotic bleeding, ileus, surgical site infection, and intra-abdominal hematoma.

CONCLUSIONS

The study implies that powered circular staplers may not significantly reduce postoperative complications, including anastomotic leakages, compared to manual staplers in colorectal surgery of high-volume centers.

AI-driven automatic compression system for colorectal anastomosis

Although circular staplers offer technical advancements over traditional hand-sewn techniques, their use remains challenging for unskilled users, necessitating substantial time and experience for mastery. In particular, it is challenging to apply a consistent pressure of an appropriate magnitude. We developed an automated circular anastomosis device using artificial intelligence (AI) to solve this problem. Automation through AI reduces experiential factors during the anastomosis process. We defined damage occurring during the anastomosis process, noting that a greater depth of damage indicated a more severe injury. For automated anastomosis, data at a tissue strain of 40% were used for the AI model, as this strain level showed optimal performance based on the accuracy and cost matrix. We compared the outcomes of automated anastomosis using a trained AI with those of unskilled users. The results were validated using the Shapiro-Wilk test and t tests. Compression damage was verified on collagen sheets. The AI-driven automatic compression system resulted in less damage compared to unskilled users. In particular, a more significant difference in damage was observed in poor-condition collagen than in good-condition collagen. Damage to the collagen under poor conditions was 54.8% when handled by unskilled users, while the AI-driven automatic compression system resulted in 38.9% damage. This study confirmed that novices' use of AI for automated anastomosis reduces the risk of damage, especially for tissues in poor condition.

Mechanical properties and tissue damage caused by staples in gastrointestinal anastomosis

Gastrointestinal surgery using a stapler is usually associated with tissue damage, anastomosis leakage, bleeding, and other complications, which is one of the effective methods for treating digestive tract cancer. The cutting properties of staples and the tissue damage occurring in the process of stapling porcine esophageal and gastric tissues have been evaluated and a new type of stapler has been designed. Since different structural and mechanical properties esophageal and gastric tissues layers, the puncturing force exhibits a fluctuating trend. Compressive stress caused by the bending of the staple legs can lead to the destruction of the vascular network inside the tissue, tissue deforms and tears. Finally, a staple with an internal incision arc (IIA) tip is designed, which meeting the performance requirements.

Compression automation of circular stapler for preventing compression injury on gastrointestinal anastomosis

Background

Conventional manual compression relies on the surgeon's subjective sensations, so excessive compression can cause tissue injury to the stapling line of the intestinal anastomosis.

Methods

Automatic compression monitoring and compression control system was developed for circular stapler. The tissue injury related compression variables were evaluated and accommodated by compression control device. The compression injury‐reducing performance was verified on collagen sheets of in vitro experiments.

Results

Excessive pressure and tissue deformation were associated with compression‐induced tissue damages. The safe pressure range was very narrow in weaker tissue than normal collagen. The automatic system performed proper compression within a safe pressure range without tissue injury.

Conclusions

Manual compression of circular stapler could cause tissue injuries by excessive pressure and tissue deformation. Our automatic compression system is designed to control peak pressure to prevent the compressive tissue injury.