125 Case Series Report: The use of ultrasound in detecting neuromas in amputees with osseointegrated prostheses

Objectives/Goals: Imaging neuromas, benign tumors of nerve tissue, can be difficult in amputees with osseointegrated (OI) prostheses, in which a metal rod is implanted into the residual limb. Magnetic resonance imaging can be inadequate due to the implanted metal. The aim of this study is to assess the use of ultrasound to detect neuromas in patients with OI prostheses. Methods/Study Population: This is a single-institutional observational study of 7 patients undergoing lower limb OI prostheses. Lower extremity nerve ultrasounds with 2-D grayscale and Doppler were completed at postoperative follow-up visits following OI prosthesis implantation. Specifically, the sciatic nerve, tibial nerve, common peroneal nerve, and sural nerve were targeted for imaging. Neuromas found on ultrasound were measured by maximal length in three planes. Results/Anticipated Results: Our study to date includes two patients with OI prostheses. The remaining patients will be accrued by the end of December. The first patient with a left below-the-knee amputation completed imaging 3 years after OI prosthesis implantation. The common peroneal nerve showed preserved fascicular architecture and morphology, with no distinct neuroma formation. However, the sural nerve demonstrated a 6 × 5 × 4 mm neuroma with minimal pain with deep palpation. The tibial nerve demonstrated a 14 × 11 × 8 mm neuroma within the medial calf musculature, with mild pain with deep palpation. The second patient with a right above-the-knee amputation was imaged 10 months after OI prosthesis implantation. The sciatic nerve demonstrated preserved fascicular morphology and terminated in a smooth taper. There was no defined neuroma. Discussion/Significance of Impact: In conclusion, we have preliminarily shown in the first two patients that ultrasound can successfully image neuromas in patients with OI prostheses in the postoperative period. Furthermore, despite a patient that was 3 years postoperative with two neuromas, the neuromas produced minimal to mild pain with targeted palpation.