# The Novel Introduction of a Thermal Camera in the Retrieval of a Retained Rectus Sheath Catheter: A Case Study

## TL;DR

A thermal camera helped locate a retained catheter after surgery when other methods failed, showing its potential as a new tool in medical imaging.

## Contribution

This case study introduces thermal imaging as a novel, radiation-free method for detecting retained surgical materials.

## Key findings

- A thermal camera successfully identified a retained rectus sheath catheter undetected by X-ray and CT.
- The patient recovered well after catheter removal guided by thermal imaging.
- Thermal imaging is proposed as a portable, safe, and precise adjunct for surgical retrieval.

## Abstract

Midline laparotomy remains essential in gynecological oncology, and rectus sheath catheters (RSCs) are commonly used for postoperative analgesia. We report the case of a 46-year-old woman who underwent midline laparotomy for a suspected ovarian mass, which intraoperatively revealed mucinous ascites consistent with pseudomyxoma peritonei. An RSC was placed for pain control; however, during removal, a 5 cm segment remained embedded in the subrectus sheath. Initial imaging with plain X-ray failed to detect the retained catheter, which was eventually confirmed by computed tomography (CT). Intraoperative localization attempts using C-arm fluoroscopy and palpation were unsuccessful. A novel adjunctive approach using a Flir One Pro smartphone-based thermal camera (Flir One Pro Systems, Sweden), approved by clinical governance and operated by a trained surgeon, successfully identified localized heat on the abdominal wall, corresponding to inflammation caused by the retained catheter. Guided by this finding, a 2 cm incision was made to retrieve the coiled catheter without complications. The patient recovered well and was discharged on the third postoperative day. Histopathology confirmed pseudomyxoma peritonei, and the case was referred to a colorectal multidisciplinary team. This report highlights the feasibility and clinical value of thermal imaging as a radiation-free, real-time adjunct for detecting retained surgical materials, particularly when conventional imaging fails. Thermal imaging offers portability, precision, and safety, though its broader adoption requires standardized training, validation, and further research.