Implementation of a Lower Extremity Amputation Formalization and Targeted Muscle Reinnervation Quality Improvement Program in a Safety-net Hospital: Feasibility and Early Results

PURPOSE: Multiple studies of lower extremity amputations (LEA) confirm high wound complication rates, neurologic pain, significant health-care utilization, and 90-day mortality upward of 20%. Previous publications reveal decreased long-term rates of neuroma and phantom limb pain with targeted muscle reinnervation (TMR) when performed at large academic centers with multidisciplinary teams. However, it is unclear whether these results translate to county safety-net hospitals where patients have advanced comorbidities and limited access to rehabilitation. The purpose of this study was to determine whether a protocol-driven approach to managing LEA at a county safety-net hospital leads to increased amputation formalization rates and decreased length of stay, readmission, and mortality rates. A second objective is to study how prophylactic TMR affects neurologic sequela. METHODS: IRB approval was obtained for a prospective study of adult patients presenting to our safety-net hospital requiring LEA. A protocol was implemented in May 2020 in combination with the General and Plastic Surgery services to perform LEA formalization and prophylactic TMR as a single surgery. Demographic information, surgical details, readmission rates, neurologic, and mortality data were collected for each patient. The prospective cohort was compared with a control cohort of historical patients who underwent LEA prior to protocol implementation (June 2017 to April 2020). Both cohorts underwent univariate analyses of primary end points. All protocol patients were also administered Numerical Rating Scale (NRS), PROMIS Intensity and Interference validated pain scales at 1 and 3 month postoperative visits. RESULTS: A total of 66 patients were included: 19 prospective and 47 historical. The prospective cohort was slightly younger (53 years versus 59 years, P < 0.01) though both cohorts had similar rates of diabetes (89% versus 85%, P = 0.75), peripheral arterial disease (47% versus 56%, P = 0.51), tobacco usage (16% versus 11%, P = 0.58), and Hemoglobin A1C (9.7 versus 8.7, P = 0.21). The indication for LEA was necrotizing infection or limb ischemia in all patients. Of the 19 protocol patients, three had AKA (average 3.0 nerve coaptations) and 16 had BKA (average 5.75 nerve coaptations). After protocol implementation, there were significant improvements in rates of amputation formalization (95% versus 51%, P = 0.009), hospital length of stay (5.5 days versus 8 days, P < 0.05), and 90-day readmission (17% versus 41%, P = 0.04), but no difference in 90-day mortality (5% versus 11%, P = 0.45). Patients undergoing formalization with prophylactic TMR had improved 1–3 month postoperative NRS scores (14.6 versus 7.1, P = 0.009), PROMIS Intensity scores (6.9 versus 4.4, P = 0.007), and PROMIS Interference scores (12.1 versus 7.6, P = 0.016). CONCLUSIONS: Patients requiring LEA have advanced comorbidities and experience high rates of perioperative wound complications, mortality, and long-term neurologic sequela. After implementing a multidisciplinary LEA protocol at a safety-net hospital, we found increased formalization rates, decreased length of stay, and readmissions. Patients undergoing prophylactic TMR during LEA formalization have significant reductions in validated pain scale scores at 3 months postoperatively. Even in resource-limited settings, implementation of multidisciplinary LEA protocol is feasible and can decrease health-care utilization, patient morbidity, and ultimately long-term neurologic sequela.