SP5.2.1 Intra-muscular interposition of nerve endings to minimise neuropathic and residual pain in lower limb amputations

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Abstract Introduction A major cause of morbidity in lower limb amputees is phantom limb pain (PLP) and residual limb pain (RLP). This study aimed to determine if surgical interposition of nerve endings into adjacent muscle bellies at the time of major lower limb amputation can decrease the incidence and severity of PLP and RLP. Methods Data was retrospectively collected from January 2015 to January 2021, including eight patients that underwent nerve interposition (NI) and 36 that received standard treatment. Primary outcomes included the 11-point Numerical Rating Scale (NRS) for pain severity, and Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity, behaviour, and interference. Secondary outcome included Neuro-QoL Lower Extremity Function assessing mobility. Cumulative scores were transformed to standardised t scores. Results Across all primary and secondary outcomes, NI patients had lower PLP and RLP. Mean ‘worst pain’ was 2 out of 10 for RLP in the NI group, compared to 3.58 in the control group (p=0.045). Mean PROMIS t scores were lower for NI cohort for both RLP (pain intensity [41.2 vs 48.1;p=0.035]; pain interference [44.9 vs 46.3;p=0.260]; pain behaviour [44.4 vs 50.8;p=0.039], and PLP (pain intensity [50.8 vs 58.5;p=0.029]; pain interference [49.1 vs 54.0;p=0.009]; pain behaviour [53.4 vs 55.6;p=0.061]). Mean Neuro-QoL t score was lower in NI cohort (45.4 vs 41.9;p=0.03). Conclusion Surgical interposition of nerve endings during lower limb amputation is a simple yet effective way of minimising PLP and RLP, improving patients’ subsequent quality of life. Additional comparisons with targeted muscle reinnervation should be performed to determine the optimal treatment option.