Anatomical basis of antropyloric transposition for fecal incontinence in humans: the infrapyloric approach

Variations in the origin of the infrapyloric artery: A systematic review and meta-analysis

BACKGROUND

The infrapyloric artery (IPA) supplies the pylorus and the large curvature of the antrum. Its common origin points include the gastroduodenal artery (GDA) and right gastroepiploic artery (RGEA). The prevalence of variations in IPA origins can be of interest to gastric cancer surgeons who wish to increase their understanding of this vessel. The primary aim of this study was to perform a systematic review and meta-analysis on the origin of the IPA. The secondary aims were to assess imaging identification accuracy, to identify IPA morphological features, and to explore the relationship of IPA origin and clinicopathological characteristics.

METHODS

Electronic databases, currently registered studies, conference proceedings and the reference lists of included studies were searched through March 2023. There were no constraints based on language, publication status, or patient demographics. Database search, data extraction and risk of bias assessment were performed independently by two reviewers. The point of origin of the IPA was the primary outcome. Secondary outcomes were imaging identification accuracy, relationship between IPA origin and clinicopathological characteristics, and IPA morphological features. A random-effects meta-analysis of the prevalence of different IPA origins was conducted. Secondary outcomes were narratively synthesized given the heterogeneity of studies reporting on these.

RESULTS

A total of 7279 records were screened in the initial search. Seven studies were included in the meta-analysis, assessing 998 patients. The IPA arose most frequently from the anterior superior pancreaticoduodenal artery (ASPDA), with a pooled prevalence of 40.4% (95% CI 17.1 - 55.8%), followed by the RGEA with a pooled prevalence of 27.6% (95% CI 8.7 - 43.7%), and the GDA with a pooled prevalence of 23.7% (95% CI 6.4 - 39.7%). Cases of multiple IPAs had a pooled prevalence of 4.9% (95% CI 0 - 14.3%). The IPA was absent in 2.6% (95% CI 0 - 10.3%) of cases and arose from the posterior superior pancreaticoduodenal artery (PSPDA) in the remaining 0.8% (95% CI 0 - 6.1%). Distance between the pylorus and the proximal branch of the IPA and distance from the pylorus to the first gastric branch of the RGEA when the IPA originated from the ASPDA and RGEA were longer than when the IPA originated from the GDA. The IPA is a small vessel (<1mm), and its origin is not related to clinicopathological characteristics including patient sex, age, and tumor stage and location.

CONCLUSIONS

Surgeons must be aware of the most common origin points of the IPA. Recommendations for future study include the stratification of IPA origin according to demographic characteristics, and further investigation into IPA morphological parameters such as tortuosity, course and relation to adjacent lymph nodes, aiding the creation of a standardized classification system pertaining to the anatomy of this vessel.

Feasibility of neurovascular antropylorus perineal transposition with pudendal nerve anastomosis following anorectal excision: a cadaveric study for neoanal reconstruction

Purpose

Perineal transposition of the antropyloric valve following an anorectal excision as a substitute for a permanent colostomy has recently been reported in humans. However, the problem of neural control still remains in these patients. Our aim herein was to study the anatomical feasibility of an anastomosis between the pudendal nerve branches (inferior rectal nerve) innervating the external anal sphincter and the anterior vagal branches of the perineally-transposed antropyloric segment in cadavers.

Methods

The antropyloric segment, along with its carefully dissected branch of the anterior vagus, was mobilized based on the left gastroepiploic pedicle in six fresh human cadavers. The antropyloric valve was then transposed in the perineum after the pudendal nerve branches had been dissected out, and an approximation of these two nerves was performed to ascertain the technical feasibility of their neural anastomosis.

Results

The anterior vagus innervating the antropylorus could be harvested in all cadavers below the hepatic division of the main vagus trunk. The inferior rectal nerve or its branches were found consistently around the 3 or the 9 o'clock position in the ischioanal fossa. An anatomical tension-free approximation of the anterior vagus branch (of the transposed antropyloric segment) to the inferior rectal nerve in the perineum was feasible in all the cadavers studied.

Conclusion

An inferior rectal nerve anastomosis with the anterior vagal branch of the perineally-transposed antropyloric segment can be achieved anatomically. This preliminary step can be the basis for future animal studies and subsequent clinical application of the procedure for possible neural control of the transposed antropyloric segment in the perineum.