# Anatomical Hepatectomy in a Patient with Situs Inversus Totalis and Right-Sided Round Ligament

## TL;DR

A rare case of successful liver surgery in a patient with mirrored internal organs and a right-sided round ligament is reported, emphasizing the importance of adjusted imaging and communication.

## Contribution

The paper presents a novel surgical approach for hepatectomy in patients with situs inversus totalis and a right-sided round ligament.

## Key findings

- Anatomical hepatectomy was successfully performed using horizontally flipped CT and 3D images to correct mirror-reversed anatomy.
- Standardizing anatomical terminology within the surgical team prevented misinterpretation and ensured safe surgery.
- The patient remained disease-free for 84 months post-surgery with no complications.

## Abstract

Situs inversus totalis (SIT) is a rare congenital anomaly characterized by mirror-image reversal of the entire thoracoabdominal viscera. Right-sided round ligament (RSRL) is another rare congenital anomaly often associated with intrahepatic vascular variations. The coexistence of these 2 anomalies is extremely rare and presents a significant challenge for hepatectomy. Here, we report a case of anatomical hepatectomy performed in a patient with SIT and RSRL.

A 50-year-old Japanese man was diagnosed with ascending colon cancer and multiple lung and liver metastases. CT revealed SIT and RSRL. The patient underwent laparoscopic colectomy followed by chemotherapy with XELOX plus bevacizumab. We planned a hepatectomy for the residual liver metastasis after 4 courses of chemotherapy. To assess the intrahepatic vasculature accurately, we horizontally flipped the CT and 3D images to correct the mirror-reversed orientation of the liver, creating standard anatomical images without SIT. We then standardized the anatomical terminology within the surgical team to prevent misinterpretation of structures during surgery. We performed anatomical hepatectomy of the dorsal area of the right paramedian sector to resect residual hepatic lesions after chemotherapy. The procedure was performed on the right side of the patient using a standard surgical approach. Histopathological examination identified a single viable nodule with hepatic metastasis, whereas the remaining nodules showed a pathological complete response. The patient recovered uneventfully and was discharged on POD 10. The patient remained alive without disease progression 84 months after hepatectomy.

We successfully performed anatomical hepatectomy in a patient with SIT and RSRL. Normalized imaging and standardization of anatomical terminology within the surgical team are key to ensuring surgical precision, preventing confusion during the operation, and avoiding potentially fatal complications of SIT and RSRL.