A novel pneumatic drill for bone biopsy under MRI imaging

Bone biopsies are currently conducted under computed tomography (CT) guidance using a battery-powered drill to obtain tissue samples for diagnosis of suspicious bone lesions. However, this procedure is suboptimal as images produced under CT lack soft tissue discrimination and involve ionizing radiation. Therefore, our team developed an MRI-safe pneumatic drill to translate this clinical workflow into the MR environment, which can improve target visualization and eliminate radiation exposure. We compare drill times and quality of samples between the 2 drills using animal bones.

Five porcine spare rib bones were obtained from a butcher shop. Each bone was drilled twice using the Arrow OnControl battery-powered drill and twice using our pneumatically actuated drill. For this study, we used an 11-gauge bone biopsy needle set with an internal core capturing thread. A stopwatch recorded the overall time of drilling for each specimen obtained.

All 20 samples collected contained a high-quality inner core and cortex. The total average time for drilling with the pneumatic drill was 8.5 s (+ / - 2.5 s) and 7.1 s (+ / - 1.4 s) with the standard battery-powered drill.

Both drills worked well and were able to obtain comparable specimens. The pneumatic drill took slightly longer, 1.39 s on average, but this extra time would not be significant in clinical practice. We plan to use the pneumatic drill to enable MRI-safe bone biopsy for musculoskeletal lesions. Biopsy under MRI would provide excellent lesion visualization with no ionizing radiation.