In situ Cryosurgery Assisted 3D Modelling Planning and Navigation by O Arm of Desmoid Tumor Preliminary Results

Introduction: Aggressive fibromatosis, is a rare, locally invasive, non-metastasizing condition.

Reasons for treatment and how? Volumetric progression, Symptoms worsening & Cosmetic disturbance.
Large en-bloc surgery is no longer regarded as the cornerstone treatment. In situ cryotherapy is a minimal invasive procedure that can decrease tumor size by apoptosis.
The proper position and the number of needles is crucial in order to ideally cover and surround the tumor mass. By 3D modelling and planning this goal can be achieved. The most effective trajectory can be determined and vital organs can be protected.

Materials and Methods: 7 patients with histolocally confirmed extra abdominal desmoid tumor with progression of tumor mass on imaging and severe functional disturbance were treated with in situ cryosurgery.
Segmentation of the tumor and surrounding structures was performed into 3D surface models. Then by extrapolating the “kill zone” of each cryotherapy needle we placed the needle in to the tumor.
According to previous planning, several isolated cryo needles were inserted into the tumor mass under O arm navigated guidance.

Results: All procedures were uneventful and all patients were discharge one day after the procedure with no complication noted. The pre-operative planning using 3D modelling allow us to correctly place the needles into the tumor mass in the most effective course.
All patients reported decrease pain and improvement of their general status and function.
The MRI scans demonstrated decrease of tumor size by an average of 42%.

Conclusions: In situ cryo-surgery in a safe procedure and effective in decreasing tumor mass in desmoid tumors. By 3D modelling correct positioning of cryo needles can be optimal and more safe for the patients. Using the O arm during the procure allows good monitoring of the ablation zone