Nagaokakyo Hospital Announces AI-Powered Surgical Training Tool for Rectovaginal Fistula Repair: Research on Perineal Body Reconstruction to Avoid Colostomy Published in International Journal

A research paper summarizing a pilot study on an AI-powered surgical guidance tool—developed by Nagaokakyo Hospital (affiliated with Central Medience Co., Ltd., headquartered in Minato-ku, Tokyo, CEO: Ryutaro Nakagawa) and Professor Tatsushi Fukuoka’s team from the Department of Information Systems Engineering, Faculty of Information Engineering, Fukuoka Institute of Technology (Fukuoka City, Fukuoka Prefecture)—has been published in the international academic journal "IJCARS: International Journal of Computer Assisted Radiology and Surgery." The tool was created by training AI on the hospital’s unique surgical experience in treating rectovaginal fistula.

This initiative aims to share under-recognized treatment methods for rare diseases via AI, with expectations for contributing to equitable medical care nationwide. The study reports on a method and outcomes for efficiently transmitting the hospital’s proprietary minimally invasive surgery for rectovaginal fistula to trainee surgeons through real-time perineal body visualization.

【Background of the Research】

What is Rectovaginal Fistula?

Rectovaginal fistula is an extremely rare obstetric complication caused by perineal laceration during vaginal delivery. Damage to the deep connective tissue known as the "perineal body" leads to the disappearance of the septum between the vagina and rectum. Internal pressure causes the rectum and vagina to perforate, and chronic cases may result in fistula formation.

This condition severely impacts patients’ quality of life (QOL), including gas and fecal leakage from the vagina, chronic vaginal bacterial infections, difficulty with defecation from the anus, and obstacles to sexual activity.

Previous Challenges

As with other rare diseases, there is no established systematic treatment protocol for rectovaginal fistula. Consequently, some medical institutions have labeled it "incurable," or recommended unnecessary treatments such as colostomy. The surgery is technically challenging, with the key step being the accurate identification of the "perineal body"—a skill that requires significant experience. While we considered using AI to share our surgical data and create a tool for identifying the perineal body, conventional AI learning methods require large datasets, posing a challenge due to the limited number of cases in rare diseases.

【Research Content】

In this study, anonymized surgical images from rectovaginal fistula patients treated at our hospital between September 2024 and May 2025 were used to train an AI model using Semantic Segmentation—a technique developed at Fukuoka Institute of Technology that enables high-accuracy learning even with few samples—to create an automated perineal body detection tool. We evaluated educational outcomes by comparing five cases each of perineal body repair surgery before and after tool implementation, assessing metrics such as operation time, blood loss, and the volume of communication between assistants and instructors. Results showed a trend toward reduced bleeding and increased instructional dialogue, suggesting high educational efficacy.

【Significance of the Study】

This study demonstrates the potential to widely disseminate our hospital’s colostomy-free perineal body reconstruction technique for this rare condition to medical facilities across Japan. Patients previously told their condition was "incurable" may now have the opportunity to regain their quality of life through specialized surgical treatment near their homes.

Going forward, we will continue efforts to enhance the accuracy of this educational method and validate its effectiveness through larger-scale studies with more cases.

To Medical Institutions

Although this condition is extremely rare, if you encounter similar cases, we encourage considering referral to specialized facilities capable of providing expert treatment.

To Patients and Families

Individuals suffering from perineal injuries after vaginal delivery are encouraged to consult with specialized medical institutions.

Publication Information

Paper Title (English):
"Artificial Intelligence System for Anatomical Landmark Detection in Rectovaginal Fistula Repair Surgery: Technical Development and Educational Evaluation"

Authors:
Koichiro Murakami¹, Tomoyuki Mizuguchi¹, Tatsushi Tokuyasu²
¹Department of Surgery, Nagaokakyo Hospital, So-shinkai Medical Corporation
²Department of Information Systems Engineering, Faculty of Information Engineering, Fukuoka Institute of Technology

Access the article online:

https://link.springer.com/article/10.1007/s11548-026-03658-4

Publication Date:
June 5, 2026 (online first; print version to follow)

Planned Conference Presentation:

The findings will also be presented at the following international conference:

July 3, 2026 – CARS; Computer Assisted Radiology and Surgery (Nagoya University)

【Glossary】

Perineal Body: A tissue structure located between the vagina and anus, serving as a crucial anatomical support for the pelvic floor.

Rectovaginal Fistula: A condition where an abnormal passage (hole) forms between the rectum and vagina.

Inquiries

So-shinkai Medical Corporation Nagaokakyo Hospital
1-20-10 Amagami, Nagaokakyo City, Kyoto Prefecture 617-0824

TEL: 075-955-1151
FAX: 075-955-1236

Contact Physician: Koichiro Murakami, Department of Surgery
Email: nagaokakyohp-mura@athena.ocn.ne.jp

【Medical Institution Overview】

About Nagaokakyo Hospital

Since its establishment in 1980, our hospital has provided community-based medical care under the philosophy of "Security and Smiles for Every Life." We treat high-frequency conditions such as colds, influenza, minor injuries, and anorectal surgeries, as well as lifestyle diseases like diabetes, and neurological disorders such as Parkinson’s disease and spinocerebellar degeneration. We also specialize in spinal surgery that directly impacts quality of life and post-perineal laceration care. Notably, our surgical treatment for rectovaginal fistula following perineal injury has one of the highest case volumes in Japan, attracting patients from across the country.

Nagaokakyo Hospital Rectovaginal Fistula Special Page

https://www.nagaokakyo-hospital.or.jp/vaginal-fistula/

〈So-shinkai Medical Corporation Nagaokakyo Hospital〉

Location: 1-20-10 Amagami, Nagaokakyo City, Kyoto Prefecture

Departments: Surgery, Gastroenterological Surgery, Anorectal Surgery, Spine Center, Orthopedics, Neurology, Cardiology, Diabetology, Rehabilitation, Radiology

Bed Capacity: 97 general beds

URL: https://www.nagaokakyo-hospital.or.jp/

〈About Central Medience Co., Ltd.〉

Founded in 2018, Central Medience Co., Ltd. operates under the vision of "Creating Innovative Medical Services" and the mission to contribute to society by enhancing health value through medical services—shifting from cure-centered care to preventive, healthcare-centered services. The company collaborates with healthcare professionals to optimize medical institutions, offering solutions in medical support, medical career development, and medical marketing.