Reply: Outcomes, Challenges, and Pitfalls after Targeted Muscle Reinnervation in High-Level Amputees: Is It Worth the Effort?

Sir: We completely agree that targeted muscle reinnervation technique revolutionized neuroma treatment, especially in high-level upper limb amputees. However, improvement is not limited to this patient cohort. In the prospective, randomized, controlled trial by Dumanian et al., the treatment of neuroma pain was successfully demonstrated in upper and lower limb amputees.1 As concluded in the study by Salminger et al., targeted muscle reinnervation represents a worthwhile procedure, even if the newly established neuromuscular interfaces are not used for prosthetic control.2 In general, most of the known surgical concepts for neuroma treatment ignore the certitude that a nerve after neuroma resection will attempt to regenerate and subsequently form a new neuroma. Therefore, treatment success of these numerous methods requires that the newly created neuroma be less symptomatic in its new environment (e.g., bone, fat, vein). However, in targeted muscle reinnervation surgery, mixed motor and sensory nerves are transferred to a muscle branch of a nearby muscle and therefore connect with motor end-plates or sensory end organs such as proprioceptors within the muscle.1 Thus, no new neuroma is formed and pain levels will decrease significantly. In the case reported by Loewenstein and Adkinson in their letter, the sensory digital nerves after ray amputation are transferred onto the motor branches of the interosseus nerves nearby. We congratulate the authors for the excellent results and the surgical approach; however, the concept of targeted muscle reinnervation for treatment of neuroma following digit amputations was recently published by Daugherty et al.3 In addition, the feasibility of reinnervating a denervated muscle with a sensory nerve, known as “sensory protection,” has been shown by Hynes et al.4 Targeted muscle reinnervation for the treatment of digital nerve neuromas is a promising adaptation of the classic targeted muscle reinnervation concept. Although it is not the goal to actually reinnervate the muscle and generate myoelectric signals, it provides the sensory nerve with a target, leading to successful nerve regeneration without neuroma formation. DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication.