Current Status of Nerve Transfers: “Supercharge End-to-Side Transfer in Severe Cubital Syndrome”

Supercharge end-to-side (SETS) technique has been increasingly implemented in the treatment of nerve pathologies. It was known for its use in ulnar injury, and although it seemed that its usefulness was more directed to injuries due to ulnar nerve section, with this work and based on all the literature available to date, the aim is to assess the possibilities of implementation based on the results of the articles published in compression-type injuries, especially those classified as severe that have little treatment available to improve their evolutionary course, and where their use to date was doubtful. A compilation is made of all the evidence to date of cubital tunnel syndrome, focused on treatments, and on the emergence of the SETS technique as a therapeutic option. The purpose of the study was to collect and review the indications, results, and complications of end-to-side axonal super feeding transfer of the interosseous nerve anterior to the ulnar nerve. Twenty-one articles that met the inclusion and exclusion criteria were finally reviewed, most of them retrospective (level of evidence IV) and some review or case series (level of evidence II/ III). The data has been pooled and analyzed focusing on the primary outcomes: intrinsic muscle recovery and complications. SETS is a successful procedure with low morbidity, which can restore the function of the intrinsic musculature in patients with severe proximal ulnar nerve compression injuries thanks to the anterior interosseous nerve (median branch) that serves as a donor. Although the technique has already begun to be introduced in the sketch of the treatment of the lesion, to implement it with assured success, prospective studies should be carried out that corroborate it with greater certainty than the articles published on the subject to date. Even so, it has been possible to verify as previous indications for performing supercharge: a normal donor nerve electromyogram (it will be performed in a pronator square), a preoperative electromyogram of the injured nerve that must have a reduced amplitude of compound muscle action potential (demonstrating axonal loss) and an electromyogram to know if the denervated motor endplates remain receptive to reinnervation (check they have spontaneous activity and this is shown by fibrillation potentials and / or acute positive waves).