CORR Insights®: How Common Are Chronic Residual Limb Pain, Phantom Pain, and Back Pain More Than 20 Years After Lower Limb Amputation for Malignant Tumors?

Abstract

Where Are We Now? Surgeons have changed how they manage patients with malignant tumors of the extremities over the last four decades, with the largest transition being the switch to limb salvage rather than amputation for the large majority of patients with bone sarcomas [8, 10, 12]. Indeed, modern day decision-making generally favors limb salvage in the absence of a specific contraindication [8]. Still, because some patients will undergo amputations, surgeons continue to try to improve how we perform these procedures. Areas of focus include amputation techniques as well as methods of preventing phantom limb pain and neuromas; generally, these studies focus on patient-reported outcomes and healthcare-related quality of life [3, 13]. Some of the more exciting discoveries have been on the topic of preventing nerve-related pain using targeted muscle reinnervation (TMR) [6], regenerative peripheral nerve interfaces (RPNI) [5], as well as other neuroma revision and prevention concepts. The current study by Döring et al. [2] is important because it focuses on the long-term outcomes and complications from the subset of patients who may not be good candidates for limb salvage. Where Do We Need To Go? Nerve-associated pain and associated sequelae can lead to poor functional outcomes and decreased mobility and prosthetic use. Research focused on minimizing these complications is an essential next step to improving function and quality of life for patients with sarcoma and limb loss. Although TMR was originally conceived of to allow autonomous zones for myoelectric prosthesis use in the upper extremity, the added benefit of decreased phantom limb pain and neuroma formation has made it an appealing technique for the lower extremity as well. A concern for TMR is that a specialized team is usually required to complete the procedure and it can increase OR time [5, 6]. RPNI has also shown excellent potential for prevention of these same nerve-related sequelae [5], and it is technically simpler and potentially easier for a wider range of surgeons. While TMR seems to have the best outcomes, it may not be a reality for widespread clinical use (due to the need for specialized teams to perform the procedure). In contrast, RPNI may be more practical because it can be performed by a non-hand surgery–trained surgeon. Well-designed studies looking at the two techniques prospectively are still needed. We also need to determine the impact each technique has on long-term pain and amputee function. Döring et al. [2] provide long-term functional and quality-of-life data for patients with amputation, which can serve as a baseline for future studies focused on amputation techniques. A large proportion of amputation-related studies focus on populations with the highest rates of amputation. This includes older patients with diabetes- or peripheral vascular disease–related complications [3, 13] as well as military and traumatic amputations [4, 11]. While these data are valuable, younger patients with sarcoma are quite different than those patient populations. Therefore, future research should focus on this younger patient group since those who survive their tumors would be expected to have both long life expectancy and high functional demands [9]. How Do We Get There? Due to the rarity of amputation for sarcoma in a younger population, a well-designed multicenter study comparing TMR and RPNI techniques would be a valuable collaborative effort. One study [1], which was the largest oncologic cohort to date (31 patients from a single institution treated with TMR for oncologic amputation), found that on short-term follow-up (1 year), the study group compared favorably to the control group, whose data were collected from a national amputee database. Building off of this study, researchers should compare TMR versus RPNI in a prospective study and include patient-reported as well as functional outcomes with a focus on prosthesis use [7]. Patient-reported outcomes and prosthesis use can be compared at 1, 3, and 5 years to definitively compare the techniques. Modern day prosthetic fitting and technology use should be integrated into this study, as well as a detailed cost analysis that examines the differences in resource requirements for the two techniques.