Regenerative Peripheral Nerve Interface: Surgical Protocol for a Randomized Controlled Trial in Postamputation Pain.

Surgical procedures, including nerve reconstruction and end-organ muscle reinnervation, have become more prominent in the prosthetic field over the past decade. Primarily developed to increase the functionality of prosthetic limbs, these surgical procedures have also been found to reduce postamputation neuropathic pain. Today, some of these procedures are performed more frequently for the management and prevention of postamputation pain than for prosthetic fitting, indicating a significant need for effective solutions to postamputation pain. One notable emerging procedure in this context is the Regenerative Peripheral Nerve Interface (RPNI). RPNI surgery involves an operative approach that entails splitting the nerve end longitudinally into its main fascicles and implanting these fascicles within free denervated and devascularized muscle grafts. The RPNI procedure takes a proactive stance in addressing freshly cut nerve endings, facilitating painful neuroma prevention and treatment by enabling the nerve to regenerate and innervate an end organ, i.e., the free muscle graft. Retrospective studies have shown RPNI's effectiveness in alleviating postamputation pain and preventing the formation of painful neuromas. The increasing frequency of utilization of this approach has also given rise to variations in the technique. This article aims to provide a step-by-step description of the RPNI procedure, which will serve as the standardized procedure employed in an international, randomized controlled trial (ClinicalTrials.gov, NCT05009394). In this trial, RPNI is compared to two other surgical procedures for postamputation pain management, specifically, Targeted Muscle Reinnervation (TMR) and neuroma excision coupled with intra-muscular transposition and burying.

Targeted Muscle Reinnervation: Surgical Protocol for a Randomized Controlled Trial in Postamputation Pain.

Over the past decade, the field of prosthetics has witnessed significant progress, particularly in the development of surgical techniques to enhance the functionality of prosthetic limbs. Notably, novel surgical interventions have had an additional positive outcome, as individuals with amputations have reported neuropathic pain relief after undergoing such procedures. Subsequently, surgical techniques have gained increased prominence in the treatment of postamputation pain, including one such surgical advancement - targeted muscle reinnervation (TMR). TMR involves a surgical approach that reroutes severed nerves as a type of nerve transfer to "target" motor nerves and their accompanying motor end plates within nearby muscles. This technique originally aimed to create new myoelectric sites for amplified electromyography (EMG) signals to enhance prosthetic intuitive control. Subsequent work showed that TMR also could prevent the formation of painful neuromas as well as reduce postamputation neuropathic pain (e.g., Residual and Phantom Limb Pain). Indeed, multiple studies have demonstrated TMR's effectiveness in mitigating postamputation pain as well as improving prosthetic functional outcomes. However, technical variations in the procedure have been identified as it is adopted by clinics worldwide. The purpose of this article is to provide a detailed step-by-step description of the TMR procedure, serving as the foundation for an international, randomized controlled trial (ClinicalTrials.gov, NCT05009394), including nine clinics in seven countries. In this trial, TMR and two other surgical techniques for managing postamputation pain will be evaluated.

Surgical treatments for postamputation pain: study protocol for an international, double-blind, randomised controlled trial.

BACKGROUND: Painful conditions such as residual limb pain (RLP) and phantom limb pain (PLP) can manifest after amputation. The mechanisms underlying such postamputation pains are diverse and should be addressed accordingly. Different surgical treatment methods have shown potential for alleviating RLP due to neuroma formation - commonly known as neuroma pain - and to a lesser degree PLP. Two reconstructive surgical interventions, namely targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI), are gaining popularity in postamputation pain treatment with promising results. However, these two methods have not been directly compared in a randomised controlled trial (RCT). Here, we present a study protocol for an international, double-blind, RCT to assess the effectiveness of TMR, RPNI, and a non-reconstructive procedure called neuroma transposition (active control) in alleviating RLP, neuroma pain, and PLP. METHODS: One hundred ten upper and lower limb amputees suffering from RLP will be recruited and assigned randomly to one of the surgical interventions (TMR, RPNI, or neuroma transposition) in an equal allocation ratio. Complete evaluations will be performed during a baseline period prior to the surgical intervention, and follow-ups will be conducted in short term (1, 3, 6, and 12 months post-surgery) and in long term (2 and 4 years post-surgery). After the 12-month follow-up, the study will be unblinded for the evaluator and the participants. If the participant is unsatisfied with the outcome of the treatment at that time, further treatment including one of the other procedures will be discussed in consultation with the clinical investigator at that site. DISCUSSION: A double-blind RCT is necessary for the establishment of evidence-based procedures, hence the motivation for this work. In addition, studies on pain are challenging due to the subjectivity of the experience and the lack of objective evaluation methods. Here, we mitigate this problem by including different pain evaluation methods known to have clinical relevance. We plan to analyse the primary variable, mean change in NRS (0-10) between baseline and the 12-month follow-up, using the intention-to-treat (ITT) approach to minimise bias and keep the advantage of randomisation. The secondary outcomes will be analysed on both ITT and per-protocol (PP). An adherence protocol (PP population) analysis will be used for estimating a more realistic effect of treatment. TRIAL REGISTRATION: ClincialTrials.gov NCT05009394.

Detección de tornillos prominentes en la articulación radiocarpiana mediante la proyección tangencial del escafoides dorsal / Detection of protruding screws in the radiocarpal joint using the "scaphoid skyline view"

INTRODUCCIÓN: Una de las complicaciones de la osteosíntesis retrógrada del escafoides es la protrusión del tornillo en la articulación radiocarpiana, dada la limitada visualización intraoperatoria del polo proximal del escafoides con las proyecciones tradicionales. OBJETIVO: Evaluar la capacidad de una nueva proyección radiológica, la proyección "tangencial del escafoides dorsal", o TED, para identificar tornillos prominentes radiocarpianos durante la osteosíntesis retrógrada del escafoides con tornillos canulados. MATERIALES Y MÉTODOS: Estudio cadavérico en muñecas frescas congeladas. Se introdujo en el escafoides un tornillo canulado con técnica retrógrada estándar. La proyección TED fue evaluada en 5 muñecas, con angulaciones del antebrazo de 15°, 30° y 45° para definir la mejor visualización del polo proximal del escafoides y del tornillo. Se comparó la capacidad para identificar la prominencia del tornillo en el polo proximal de la proyección TED de 30° con 5 proyecciones tradicionales de escafoides en 9 muñecas. El tornillo se posicionó a nivel de la superficie del escafoides, y luego se avanzó a intervalos de 0,5 mm bajo visualización directa por artrotomía dorsal. Tras cada intervalo, se repitieron todas las proyecciones para determinar su capacidad de detectar tornillos prominentes en el escafoides. RESULTADOS: La mejor visualización del polo proximal del escafoides se logró con la proyección TED de 30°. Al comparar la proyección TED de 30° y las tradicionales, con la TED se logró identificar tornillos prominentes a 0,8 mm promedio, seguida por la proyección posteroanterior con cubitalización y extensión a 1.3 mm (p » 0.014), con una alta precisión y correlación interobservador de estas proyecciones. CONCLUSIÓN: La proyección TED demostró ser la más sensible para detectar tornillos prominentes en la articulación radiocarpiana. Su uso rutinario podría evitar complicaciones durante la osteosíntesis.

INTRODUCTION: One of the complications of the retrograde percutaneous scaphoid fixation is the protrusion of the screw in the radiocarpal joint due to the limited intraoperative visualization of the proximal pole of the scaphoid with the traditional radiographic views. OBJETIVE: To evaluate the sensitivity of a novel radiographic view (the skyline scaphoid view, SSV) to detect screws protruding in the radiocarpal joint during the retrograde fixation of the scaphoid. MATERIALS AND METHODS: We studied nine cadaverous fresh frozen wrists. A retrograde cannulated screw was inserted in the scaphoid. To validate the SSV, 5 wrists were studied, comparing 3 forearm angulations (15°, 30° and 45°) to get the best visualization of the proximal pole and screw. We compared the ability to identify the protrusion of the screw in the proximal pole of the 30° SSV with that of 5 standard scaphoid radiographic views in 9 wrists. The screw was positioned at the level of the surface of the scaphoid, and was sequentially protruded in 0.5 mm increments, with direct visualization of its tip through a dorsal capsulotomy. After each increment, all views were repeated to determine if they were able to detect screws projecting from the scaphoid. RESULTS: The best visualization of the proximal pole of the scaphoid was found with the 30° SSV. In the comparison of the 30° SSV and the standard views, with the SSV we were able to identify the protrusion of the screws at an average of 0.8 mm, followed by the posterior-anterior view with ulnar deviation and extension at 1.3 mm (p » 0.014), with high precision and interobserver agreement regarding these views. CONCLUSION: The SSV was the most sensitive view to detect protruding screws in the proximal pole of the scaphoid. Its routine use could avoid complications during osteosynthesis.

Solutions for the Unstable and Arthritic Distal Radioulnar Joint.

An unstable and osteoarthritic distal radioulnar joint presents with considerable functional impairment, pain, and weakness in gripping manipulation of objects. A wide variety of surgical alternatives have been described to address these concerns. Resection arthroplasties include different types of distal ulna resection and soft tissue procedures; good overall results have been described for these types of procedures, although they have shown limitations in achieving and maintaining pain relief and stability, especially in more active patients. Since the late 1980s, partial and total joint arthroplasties have emerged as good alternatives for treatment in young and more active patients.

Shoulder Terrible Triad: Classification, Functional Results, and Prognostic Factors.

INTRODUCTION: The shoulder terrible triad (STT) is a traumatic anterior shoulder dislocation, associated with rotator cuff (RC) tear and nerve injury from the brachial plexus. This study aimed to describe the functional results and prognostic factors of surgery in patients with STT. METHODS: Thirty consecutive patients with acute STT were included at the same institution. All patients were examined with x-rays, MRI, and electromyography. Surgical treatment in the acute setting was indicated to address an RC injury or a displaced greater tuberosity fracture. Variables registered on the day of surgery were preoperative Constant and Western Ontario Rotator Cuff (WORC) scores and injury pattern. At final discharge, Constant, American Shoulder and Elbow Surgeons (ASES), WORC, and subjective shoulder value scores were recorded by an independent evaluator. RESULTS: Twenty-seven patients underwent a complete follow-up. The dominant arm was affected in 50% of cases. The mean follow-up was 27 (12 to 43) months. The mean WORC and Constant scores improved from 1,543 to 1,093 (P = 0.015) and 31 to 54 (P = 0.003), respectively. The ASES and subjective shoulder value scores at the end of the follow-up were 60 and 56 points, respectively. RC tears and nerve injuries that did not involve the axillary or suprascapular nerves were associated to better results than greater tuberosity fractures and injuries to the axillary or suprascapular nerves, respectively, in WORC (P = 0.028), Constant (P = 0.024), and ASES scores (P = 0.035). Preoperative WORC and Constant scores were independent prognostic factors. CONCLUSIONS: The most frequent patterns include complete RC tears, anterior capsular injuries, and an axillary nerve injury. Patients had improved functional scores at the end of follow-up after surgery. Better functional results were correlated to RC tears, injuries to nerves with innervation distal to the shoulder, and higher preoperative Constant and WORC scores.