Results of wrist extension reconstruction in C5–8 brachial plexus palsy by transferring the pronator quadratus motor branch to the extensor carpi radialis brevis muscle

Abstract

T radiTionally, it has been accepted that if the C5-7 roots are injured, there will be palsy of shoulder abduction/external rotation, elbow flexion/extension, and thumb and finger extension.1 Although this belief is widely held, it is inconsistent with well-accepted myotome charts for the upper limb.9 For instance, it is accepted that thumb and finger extensors are innervated by the C-7 and C-8 roots; consequently, preservation of thumb and finger span should be observed in C5-7 root injuries. Bertelli and Ghizoni 4 have demonstrated that C5-7 root injuries do not cause palsies of elbow, wrist, or finger extension. In such cases, radial wrist extensors are paralyzed, but strong wrist extension is preserved because the extensor carpi ulnaris remains functional. Bertelli and Ghizoni 3 have also demonstrated that what was clinically conceived to be a C5-7 root palsy may in fact be a C5-8 root injury. Fattah et al. reached the same conclusions in children.12 In a few patients with C5-8 root palsies, thumb and finger extension is preserved because the T-1 root participates in the innervation of thumb and finger extensors.3 In these patients, if thumb and finger extensors are strong enough, wrist extension can be accomplished using these muscles. However, concomitant with the patient flexing his or her fingers to grasp an object, the wrist drops because there is no active wrist extensor to maintain the wrist in extension. When the wrist is flexed, grasp power is essentially lost.15 In C5-8 root injuries, such patients, as well as those patients with clear palsies of wrist extension, need reconstruction of wrist extensors.Very few options are available for wrist extensor reconstruction in such extended upper-type palsies of the upper limb, because only a limited number of donor nerves and tendons are available. Common donors for tendon transfers to correct a dropped wrist include the pronator teres obJective The objective of this study was to report the results of pronator quadratus (PQ) motor branch transfers to the extensor carpi radialis brevis (ECRB) motor branch to reconstruct wrist extension in C5-8 root lesions of the brachial plexus. methods Twenty-eight patients, averaging 24 years of age, with C5-8 root injuries underwent operations an average of 7 months after their accident. In 19 patients, wrist extension was impossible at baseline, whereas in 9 patients wrist extension was managed by activating thumb and wrist extensors. When these 9 patients grasped an object, their wrist dropped and grasp strength was lost. Wrist extension was reconstructed by transferring the PQ motor to the ECRB motor branch. After surgery, patients were followed for at least 12 months, with final follow-up an average of 22 months after surgery. results Successful reinnervation of the ECRB was demonstrated in 27 of the 28 patients. In 25 of the patients, wrist extension scored M4, and in 2 it scored M3. coNclusioNs In C5-8 root injuries, wrist extension can be predictably reconstructed by transferring the PQ motor branch to reinnervat...

Editorial: Radial nerve

“…8 Several studies have reported spontaneous recovery from the injury for more than 75% of patients after 3 months, 1,13 so in most patients with typical humeral shaft-associated radial nerve injuries, we recommend waiting 4 months, with serial clinical and electrophysiological follow-up prior to exploration. However, for the proximal radial nerve injuries associated with severe stretch mechanisms, as in the series reported herein, 3 we too would recommend exploration by 3-4 months, with intention for nerve grafting.…”

“…In this article, Bertelli and Ghizoni report on 13 patients with proximal radial nerve injuries, which resulted from high-velocity stretch mechanisms; all patients were injured in motorcycle accidents and many had concomitant musculoskeletal injuries, and several had injuries to other brachial plexus elements. 3 The prevalence of proximal radial nerve injuries is still unknown, unlike the detailed knowledge about the risk of radial nerve palsy due to humeral shaft fractures. The prevalence of radial nerve palsy due to humeral shaft fractures is 11.8%; however, when the shaft length is divided into thirds, only 1.8% of the proximal third fractures are associated with radial palsy, whereas a 15.2% incidence is associated with middle shaft fractures and 23.6% with distal third shaft fractures.…”

“…4 This was associated with M4-level recovery in 23 of our 24 patients with C5-8 brachial plexus palsy, and with M4 in all 7 of our patients with a radial nerve palsy. 3 With radial nerve or posterior cord palsies, as opposed to lesions of the brachial plexus, the pronator quadratus motor branch is fully functional, which ensures a better outcome.…”

Inervación del Músculo Extensor Radial Corto del Carpo en Individuos Brasileños: Biometría de su Origen y Distribución

“…El ramo para el músculo extensor radial corto del carpo (MERCC) ha sido utilizado con frecuencia para restablecer las funciones de antebrazo, muñeca y mano en pacientes con lesiones medulares, del plexo braquial o lesiones que afecten sus ramos terminales (Hsiao et al, 2009;Bertelli et al, 2012Bertelli et al, , 2016.…”

“…El ramo para el MERCC se ha utilizado como nervio donante para el ramo interóseo anterior, flexor largo del pulgar y pronador redondo (Bertelli et al, 2012;Bertelli, 2015), con resultados exitosos en la recuperación principalmente de la flexión de los dedos y oposición de pulgar. Así mismo se han transferido ramos nerviosos hacia el nervio del MERCC, tales como el ramo para el músculo flexor superficial de los dedos, recuperando la función extensora de muñeca en daños por avulsión del plexo braquial a nivel de C5-C6-C7 (Ukrit et al, 2009) y transferencias desde el nervio para el músculo pronador cuadrado, ramo terminal del nervio interóseo anterior en lesiones de plexo braquial C5 -C8 recuperando exitosamente la extension de muñeca (Bertelli et al, 2016).…”