# Robot-Assisted Abdominoperineal Resection for Anal Fistula Cancer in a Patient with Situs Inversus Totalis: A Case Report

## TL;DR

A 75-year-old man with a rare condition had successful robot-assisted surgery for anal fistula cancer due to reversed internal organs.

## Contribution

Demonstrates the feasibility of robot-assisted surgery for colorectal cancer in a patient with situs inversus totalis.

## Key findings

- Robot-assisted abdominoperineal resection was safely performed with minimal blood loss and no complications.
- Surgical setup and techniques were adapted to accommodate the patient's mirror-image anatomy.
- The case supports the use of robotic platforms in complex anatomical scenarios.

## Abstract

Situs inversus totalis (SIT) is a rare congenital condition characterized by a complete mirror-image reversal of thoracic and abdominal organs. This anatomic anomaly poses technical challenges in abdominal surgery, particularly in oncologic procedures requiring precise orientation and dissection. Robot-assisted surgery (RS) offers advantages such as stable visualization and enhanced dexterity, which may facilitate safe and effective surgery even in patients with reversed anatomy. However, reports of using RS for colorectal cancer in the setting of SIT remain scarce.

A 75-year-old man was referred to our department for evaluation and management of an anal fistula. A comprehensive diagnostic workup revealed carcinoma with cutaneous invasion arising from the anal fistula in the context of SIT. Because of the cutaneous invasion, curative resection was indicated, and the patient underwent robot-assisted abdominoperineal resection (RAPR). To accommodate the mirror-image anatomy, the surgical setup—including the positioning of robotic arms, monitors, surgeon, assistant, and scrub nurse—was reversed relative to the standard configuration. Lymphadenectomy and vascular ligation were performed using a medial-to-lateral approach adapted in a left-right inverted fashion. While pelvic dissection and lateral mobilization were conducted using the surgeon’s right hand in a standard manner, cranial-side medial dissection and vascular handling were performed using the surgeon’s left hand after instrument exchange. The operative time was 334 min, there was minimal blood loss (15 mL), and the patient’s postoperative course was uneventful.

RS is a feasible and safe option for patients with SIT undergoing colorectal cancer resection. This case highlights the adaptability of robotic platforms in facilitating unique techniques in the setting of complex anatomical variations. It supports their utility in achieving precise and complication-free oncologic surgery in rare scenarios. Further accumulation of similar patient reports is warranted to establish standardized strategies and validate outcomes.