Enhancing sensory perception in upper limb prosthetics through combined Targeted Muscle Re-innervation and osseointegration

Purpose Upper limb amputation significantly impairs physical and psychosocial functioning. Many upper limb amputees discontinue prosthesis use due to a multitude of complications. We embarked on a study that merged the surgical techniques of osseointegration and targeted muscle reinnervation (TMR) to explore the potential enhancement of sensory perception in a prosthetic limb. Osseointegration involves skeletal anchorage of an implant and abutment to establish a direct attachment point for a prosthesis. TMR involved transfer of residual peripheral nerves to nearby redundant motor nerves creating biologic amplifiers that convert native neural signals into distant muscle contractions. Both TMR and osseointegration are known to improve sensibility and proprioception, combining these procedures will improve intuitive control. Methods Routine testing on the prosthetic limb for patients enrolled in the Advanced Surgical Amputee Program (ASAP) included two-point discrimination, monofilament assessment and vibration detection. These tests were conducted at numerous time points pre and post osseointegration and were assessed for any improvement. All patients had already undergone TMR. Results Four patients were included in this study. The results showed variable improvement in deep pressure sensation detection, consistent improvement in vibration detection and no improvement in two-point discrimination. We also found an improved ability to correctly identify the location of a stimulus. Conclusion This study provides early evidence supporting a positive correlation between improved sensibility and spatial awareness when combining osseointegration and TMR. We recommend future research with larger cohorts and longer follow-up periods to validate and strengthen these findings.