Dynamic computer-navigated biopsies of osseous lesions in the mandible: an experimental proof of concept study

Gaining representative biopsy samples in suspicious mandibular bone structures represents a challenging procedure as a result of the complex associated anatomy. Although 3D-printed drilling templates have been reported to improve biopsy accuracy significantly compared to freehand procedures, only limited data is available on the precision of dynamically navigated biopsies. The aim of this experimental study was to compare the accuracy of dynamically navigated biopsies with freehand biopsy procedures. Computed tomography data of virtual mandibular (suspicious) bone lesions was segmented and reconstructed into complete 3D-models. Subsequently, two identical mandibular models – one for the navigation group and one for the freehand group - including the intracortical lesion were produced using 3D-printing. This was followed by Cone Beam Computed Tomography (CBCT) of each model for resegmentation and planning of a standardized biopsy channel. For simulating realistic clinical conditions, the models were fixed in a phantom head and on an operating table. In the navigation group the biopsies were performed using a dynamic navigation system (X-Guide) and in the control group the biopsies were performed by freehand procedure. Following the experimental surgical procedures the models were scanned again (CBCT) and the accuracy was assessed by calculating the deviation of the actual biopsy axis from the planned axis. Eight comparable biopsies were performed by using the dynamic navigation system and the freehand procedures in each group. The mean deviation between the planned axis and the actual biopsy path was significantly lower in the navigation group (1.51 mm ± 0.5 mm) than in the freehand group (4.11 mm ± 1.9 mm). Dynamically navigated biopsies of the mandible show a significantly higher accuracy than freehand procedures and represent a promising novel method for improving diagnostic certainty for biopsies of suspicious structure in the mandible.