# Three-Dimensional Surgical Planning in Mandibular Cancer: A Decade of Clinical Experience and Outcomes

## TL;DR

This study examines the use of 3D surgical planning in jaw cancer treatment over ten years, showing high accuracy and tumor-free margins but also identifying areas for improvement.

## Contribution

The study provides a long-term clinical evaluation of 3D virtual surgical planning outcomes in mandibular cancer treatment.

## Key findings

- 93.7% of bone margins were tumor-free with a median time to surgery of 34 days.
- PSI reconstructions were more accurate in intergonial distance and coronal angle than conventional plates.
- Non-bony reconstructions had higher plate-related complications compared to bony reconstructions.

## Abstract

Cancer of the mouth often requires removal of part of the jaw. Dutch guidelines recommend surgical treatment within 30 days and the achievement of tumor-free bone margins of >5 mm. Three-dimensional virtual surgical planning has become standard practice in treatment planning as it improves accuracy and predictability of resection and reconstruction. Resections are performed using resection guides, followed by reconstruction with either hand-bent plates or 3D-designed implants. This study evaluates guideline adherence, plate-related complications, and the accuracy of 3D-planned mandibular resection and reconstruction using different osteosynthesis plates. The median time to surgery in this cohort slightly exceeded the guideline recommendations, and a high percentage of bone margins were tumor-free. Bridging the mandibular gap with just a reconstruction plate showed higher plate-related complications compared to reconstructions in which bone could be inserted. Resection was performed with high accuracy. Reconstructions with 3D-designed implants were more accurate in selected dimensions than conventional plates.

Background: Three-dimensional virtual surgical planning (Three-dimensional VSP) has become standard practice in the treatment of mandibular oral squamous cell carcinoma (OSCC) in the last decade. Dutch guidelines recommend a care pathway interval (CPI) of a maximum of 30 days, and a free bone margin of at least 5 mm. Fused MRI and CT data are used for accurate tumor delineation. Based on this data, a virtual surgical plan is created and transferred to the operating room using resection guides and patient-specific implants (PSIs). Long-term evaluation is needed to further optimize its clinical use. Objectives: This study evaluates adherence to bone margin and CPI guidelines in mandibular OSCC. Additionally, it assesses the accuracy of tumor resection and reconstruction using 3D-VSP and compares the complications of 3D-planned mandibular reconstruction using different kinds of osteosynthesis plates. Methods: All patients who underwent a segmental mandibulectomy between 2014 and 2024 at the University Medical Center Groningen were included. CPI, clinical outcomes, and complications were analyzed. The preoperative virtual plan was compared with the postoperative outcome to assess accuracy. Results: The median CPI was 34 days, and 93.7% of bone margins were tumor-free. Mean absolute resection deviation was 1.63 mm (±1.42). PSI reconstructions were significantly more accurate in intergonial distance and coronal angle compared to conventional plates. Plate-related complications were more common in non-bony reconstructions; PSI reconstructions showed significantly more plate exposure. Conclusions: 3D-VSP leads to high accuracy in resection and reconstruction and favorable bone margins. Shortening the CPI and reducing biological complications are essential to further improve oncological outcomes.