MRI based navigated cryosurgery of extra-abdominal desmoid tumors: A proof of concept study

Background: Computer-guided MRI navigation for soft tissue tumors remains a challenge due to lack of a fixed landmark for registration. Extra-abdominal Desmoid Tumors (EDTs) are soft tissue tumors for which image-guided percutaneous cryosurgery (CRA) has emerged as a valid treatment modality. Successful CRA relies on precise intraoperative image guidance. This study, present a novel approach of using skin fiducial markers to overcome this challenge and navigate insertion of MRI-based CRA needles as a treatment for symptomatic or progressive EDTs. Methods: In this retrospective study, conducted between 2018-2020, eleven patients at a single center with symptomatic or progressive EDTs were treated with CRA using intraoperative MRI navigation. 15 cryoablation procedures were performed, each adhering to a personalized pre-operative plan. We compared the total tumor size, necrotic and viable portions pre- and post-operation, and the SF-36 questionnaire evaluating subjective health.Results: All CRAs demonstrated 100% adherence to the pre-determined plan. Overall, tumor size decreased significantly (p-value=0.02). Four patients required additional CRAs. Only one patient’s tumor did not reduce in size. There was a significant reduction in viable tissue, (p-value=0.03), but not in necrotic tissue (p-value=0.66). According to the SIR adverse event classification guidelines, one participant experienced muscle necrosis, a mild complication. Both the physical and mental scores improved significantly (p-value (physical)=0.002; p-value (mental)<0.000).Conclusion: These findings demonstrate the feasibility and efficacy of performing percutaneous cryosurgery using skin fiducial marker registration and MRI-computed navigation to safely treat EDTs. This navigation approach may be implemented in other soft tissue procedures requiring precision navigated surgery. Trial Registration: Retrospectively registered.