{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T14:29:22Z","timestamp":1774362562428,"version":"3.50.1"},"reference-count":43,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T00:00:00Z","timestamp":1774310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Selective transfer of an ulnar nerve fascicle to the motor branch of the musculocutaneous nerve (Oberlin technique) is widely used to restore elbow flexion following upper brachial plexus injury. Intraoperative neurophysiological mapping allows quantitative recording of compound muscle action potentials (CMAPs) during donor fascicle selection; however, its prognostic relevance remains unclear. This study evaluated whether intraoperative flexor carpi ulnaris (FCU) CMAP amplitude is associated with time to electromyographic reinnervation of the biceps brachii and with final functional outcomes. Methods: A retrospective observational study was conducted including patients who underwent selective nerve transfer to the biceps brachii between 2006 and 2025 at two tertiary referral centers. Donor fascicles were selected using intraoperative neurophysiological mapping with quantitative CMAP recordings from three ulnar-innervated muscles. Primary outcomes were time to electromyographic evidence of reinnervation and final elbow flexion strength assessed using the British Medical Research Council grading system. Associations were analyzed using nonparametric statistical methods. Results: Twenty patients met the inclusion criteria. Higher intraoperative FCU CMAP amplitudes were associated with a shorter time to electromyographic reinnervation (Spearman \u03c1 = \u22120.572, p = 0.0106). No association was observed between CMAP amplitude and final elbow flexion strength (Spearman \u03c1 = \u22120.168, p = 0.479), or between time to reinnervation and final functional outcome (Spearman \u03c1 = \u22120.276, p = 0.253). A positive association was found between the injury-to-surgery interval and intraoperative CMAP amplitude (Spearman \u03c1 = 0.681, p = 0.000943). Conclusions: The intraoperative FCU CMAP amplitude facilitates objective donor fascicle selection and is associated with earlier electromyographic reinnervation. Nevertheless, it was not associated with final elbow flexion strength in this cohort and should be interpreted as a technical adjunct rather than a standalone prognostic indicator. Functional recovery following nerve transfer appears to reflect multifactorial biological and temporal determinants beyond a single intraoperative neurophysiological measurement. These findings should be interpreted cautiously given the limited sample size.<\/jats:p>","DOI":"10.3390\/jcm15072476","type":"journal-article","created":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T12:58:59Z","timestamp":1774357139000},"page":"2476","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Intraoperative FCU CMAP Amplitude During Oberlin Nerve Transfer: Association with Reinnervation Timing and Functional Outcomes"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4303-9074","authenticated-orcid":false,"given":"Diana M.","family":"Ortega-Hern\u00e1ndez","sequence":"first","affiliation":[{"name":"Hand and Microsurgery Unit, Traumaunit, Teknon Medical Center, 08022 Barcelona, Spain"},{"name":"PhD Program in Medicine and Translational Research, Faculty of Medicine and Health Sciences, Universitat de Barcelona, 08036 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Isabel","family":"Fern\u00e1ndez-Conejero","sequence":"additional","affiliation":[{"name":"Department of Intraoperative Neurophysiology, Bellvitge Universitary Hospital, Universitat de Barcelona, 08907 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9116-9167","authenticated-orcid":false,"given":"Aroa","family":"Casado-Rodr\u00edguez","sequence":"additional","affiliation":[{"name":"Human Anatomy and Embryology Unit, Department of Surgery and Medical-Surgical Specialties, Faculty of Medicine (Campus Cl\u00ednic), Universitat de Barcelona, 08036 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-7617-7811","authenticated-orcid":false,"given":"Guillermo J.","family":"Tarnawski-Espa\u00f1ol","sequence":"additional","affiliation":[{"name":"Orthopaedic Surgery and Traumatology Department, Hospital Fraternidad-Muprespa Habana, 28036 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Julia","family":"Mir\u00f3-Llad\u00f3","sequence":"additional","affiliation":[{"name":"Department of Intraoperative Neurophysiology, Bellvitge Universitary Hospital, Universitat de Barcelona, 08907 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joaquin","family":"Casa\u00f1as-Sintes","sequence":"additional","affiliation":[{"name":"Hand and Microsurgery Unit, Traumaunit, Teknon Medical Center, 08022 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manuel","family":"Llus\u00e1-P\u00e9rez","sequence":"additional","affiliation":[{"name":"Human Anatomy and Embryology Unit, Department of Surgery and Medical-Surgical Specialties, Faculty of Medicine (Campus Cl\u00ednic), Universitat de Barcelona, 08036 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1016\/0363-5023(94)90011-6","article-title":"Nerve transfer to biceps muscle using a part of ulnar nerve for C5\u2013C6 avulsion of the brachial plexus: Anatomical study and report of four cases","volume":"19","author":"Oberlin","year":"1994","journal-title":"J. Hand Surg. Am."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1054\/jhsb.2000.0367","article-title":"Transfer of a single fascicle from the ulnar nerve to the biceps muscle after avulsions of upper roots of the brachial plexus","volume":"25","author":"Sungpet","year":"2000","journal-title":"J. Hand Surg. Am."},{"key":"ref_3","first-page":"15","article-title":"Functional outcome of nerve transfer for restoration of shoulder and elbow function in upper brachial plexus injury","volume":"3","author":"Venkatramani","year":"2008","journal-title":"J. Brachial Plex. Peripher. Nerve Inj."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"195","DOI":"10.3171\/2014.9.JNS132823","article-title":"Upper brachial plexus injury in adults: Comparative effectiveness of different repair techniques","volume":"122","author":"Ali","year":"2015","journal-title":"J. Neurosurg."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"822","DOI":"10.1227\/NEU.0b013e31822848eb","article-title":"Outcome after delayed Oberlin transfer in brachial plexus injury","volume":"69","author":"Sedain","year":"2011","journal-title":"Neurosurgery"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.jhsa.2003.10.013","article-title":"Reconstruction of C5 and C6 brachial plexus avulsion injury by multiple nerve transfers: Spinal accessory to suprascapular, ulnar fascicles to biceps branch, and triceps long or lateral head branch to axillary nerve","volume":"29","author":"Bertelli","year":"2004","journal-title":"J. Hand Surg. Am."},{"key":"ref_7","first-page":"275","article-title":"Transferts de fascicules du nerf ulnaire sur le nerf du muscle biceps dans les avulsions C5\u2013C6 ou C5\u2013C6\u2013C7 du plexus brachial","volume":"16","author":"Loy","year":"1997","journal-title":"Ann. Chir. Main Memb. Super."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1302\/0301-620X.93B3.24634","article-title":"Use of quantitative intra-operative electrodiagnosis during partial ulnar nerve transfer to restore elbow flexion","volume":"93","author":"Suzuki","year":"2011","journal-title":"J. Bone Joint Surg. Br."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1485","DOI":"10.2106\/00004623-200407000-00018","article-title":"Transfer of fascicles from the ulnar nerve to the nerve to the biceps in the treatment of upper brachial plexus palsy","volume":"86","author":"Teboul","year":"2004","journal-title":"J. Bone Joint Surg. Am."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"E7","DOI":"10.3171\/foc.2004.16.5.7","article-title":"Reinnervation of the biceps in C5\u20137 brachial plexus avulsion injuries: Results after distal bypass surgery","volume":"16","author":"Ferraresi","year":"2004","journal-title":"Neurosurg. Focus"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"313","DOI":"10.3171\/jns.2003.98.2.0313","article-title":"Nerve transfers to the biceps and brachialis branches to improve elbow flexion strength after brachial plexus injuries","volume":"98","author":"Tung","year":"2003","journal-title":"J. Neurosurg."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1007\/BF01653132","article-title":"Histomorphometry of the ulnar nerve and its branches","volume":"20","author":"Osman","year":"1998","journal-title":"Surg. Radiol. Anat."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1093\/brain\/68.4.243","article-title":"The intraneural topography of the radial, median and ulnar nerves","volume":"68","author":"Sunderland","year":"1945","journal-title":"Brain"},{"key":"ref_14","unstructured":"Sunderland, S. (1978). Nerves and Nerve Injuries, Churchill Livingstone."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0363-5023(80)80035-9","article-title":"Internal topography of major nerves of the forearm and hand: A current view","volume":"5","author":"Jabaley","year":"1980","journal-title":"J. Hand Surg. Am."},{"key":"ref_16","first-page":"383","article-title":"Intraneural distribution of the ulnar nerve","volume":"54","author":"Llusa","year":"2010","journal-title":"Rev. Esp. Cir. Ortop. Traumatol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2002","DOI":"10.1016\/j.jhsa.2011.08.017","article-title":"Fascicular selection for nerve transfers: The role of the nerve stimulator when restoring elbow flexion in brachial plexus injuries","volume":"36","author":"Bhandari","year":"2011","journal-title":"J. Hand Surg. Am."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"978","DOI":"10.1016\/j.jhsa.2005.05.014","article-title":"Results of reinnervation of the biceps and brachialis muscles with a double fascicular transfer for elbow flexion","volume":"30","author":"Mackinnon","year":"2005","journal-title":"J. Hand Surg. Am."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/micr.31178","article-title":"Optimizing donor fascicle selection in Oberlin\u2019s procedure: A retrospective review of anatomical variability using intraoperative neuromonitoring","volume":"44","author":"Marina","year":"2024","journal-title":"Microsurgery"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1017\/S0317167100047338","article-title":"A quarter century\u2019s experience with intraoperative nerve action potential recording","volume":"20","author":"Kline","year":"1993","journal-title":"Can. J. Neurol. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1055\/s-0030-1263291","article-title":"Intraoperative decision making by electrophysiological detection of the origin of thoracodorsal nerve in the C7 nerve root transfer procedure","volume":"27","author":"Lu","year":"2011","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"631","DOI":"10.3171\/jns.1983.58.5.0631","article-title":"Operative management of selected brachial plexus lesions","volume":"58","author":"Kline","year":"1983","journal-title":"J. Neurosurg."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"181","DOI":"10.3171\/2018.3.PEDS17529","article-title":"Effect of fascicle composition on ulnar to musculocutaneous nerve transfer (Oberlin transfer) in neonatal brachial plexus palsy","volume":"22","author":"Smith","year":"2018","journal-title":"J. Neurosurg. Pediatr."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1002\/mus.20707","article-title":"Peripheral nerve stimulation and monitoring during operative procedures","volume":"35","author":"Crum","year":"2007","journal-title":"Muscle Nerve"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"A55","DOI":"10.1227\/01.NEU.0000341165.83218.AC","article-title":"Nerve transfer surgery for adult brachial plexus injury: A 10-year experience at Louisiana State University","volume":"65","author":"Sulaiman","year":"2009","journal-title":"Neurosurgery"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1016\/j.jhsa.2023.01.019","article-title":"Indications and technique for the use of intraoperative neuromonitoring in brachial plexus surgery","volume":"48","author":"Zelenski","year":"2023","journal-title":"J. Hand Surg. Am."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1016\/j.jhsa.2005.09.019","article-title":"Combined nerve transfers for C5 and C6 brachial plexus avulsion injury","volume":"31","author":"Leechavengvongs","year":"2006","journal-title":"J. Hand Surg. Am."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1097\/PRS.0000000000005720","article-title":"Outcomes of single versus double fascicular nerve transfers for restoration of elbow flexion in patients with brachial plexus injuries: A systematic review and meta-analysis","volume":"144","author":"Sneiders","year":"2019","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.hcl.2004.10.004","article-title":"Nerve transfers in adult brachial plexus injuries: My methods","volume":"21","author":"Chuang","year":"2005","journal-title":"Hand Clin."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"e6460","DOI":"10.1097\/GOX.0000000000006460","article-title":"Impact of surgery timing on outcomes after nerve transfer to restore elbow flexion","volume":"13","author":"Hicks","year":"2025","journal-title":"Plast. Reconstr. Surg. Glob. Open"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.jhsa.2013.09.042","article-title":"Preoperative donor nerve electromyography as a predictor of nerve transfer outcomes","volume":"39","author":"Schreiber","year":"2014","journal-title":"J. Hand Surg. Am."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1177\/1753193419851092","article-title":"Factors associated with failed ulnar nerve fascicle to biceps motor branch transfer: A case-control study","volume":"44","author":"Lovy","year":"2019","journal-title":"J. Hand Surg. Eur. Vol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"135e","DOI":"10.1097\/PRS.0000000000000795","article-title":"Optimal axon counts for brachial plexus nerve transfers to restore elbow flexion","volume":"135","author":"Schreiber","year":"2015","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"123438","DOI":"10.1016\/j.jns.2025.123438","article-title":"Evaluating motor unit properties after nerve transfer surgery","volume":"472","author":"Debenham","year":"2025","journal-title":"J. Neurol. Sci."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"332","DOI":"10.1016\/j.jhsa.2009.12.002","article-title":"Nerve transfers: Indications, techniques, and outcomes","volume":"35","author":"Tung","year":"2010","journal-title":"J. Hand Surg. Am."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2350","DOI":"10.1016\/j.jhsa.2012.07.030","article-title":"Factors affecting outcome of triceps motor branch transfer for isolated axillary nerve injury","volume":"37","author":"Lee","year":"2012","journal-title":"J. Hand Surg. Am."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1111\/j.1529-8027.2000.00026.x","article-title":"Influence of aging on peripheral nerve function and regeneration","volume":"5","author":"Ceballos","year":"2000","journal-title":"J. Peripher. Nerv. Syst."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1097\/01.prs.0000200628.15546.06","article-title":"Preliminary results of double nerve transfer to restore elbow flexion in upper type brachial plexus palsies","volume":"117","author":"Liverneaux","year":"2006","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1093\/ons\/opx184","article-title":"Age as a predictor of long-term results in patients with brachial plexus palsies undergoing surgical repair","volume":"15","author":"Socolovsky","year":"2018","journal-title":"Oper. Neurosurg."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"123510","DOI":"10.1016\/j.wneu.2024.11.093","article-title":"Outcomes of Oberlin transfer in elderly patients: A case series","volume":"194","author":"Guedes","year":"2025","journal-title":"World Neurosurg."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"711","DOI":"10.1016\/S0363-5023(98)80059-2","article-title":"Nerve transfer to biceps muscle using a part of the ulnar nerve in brachial plexus injury (upper arm type): A report of 32 cases","volume":"23","author":"Leechavengvongs","year":"1998","journal-title":"J. Hand Surg. Am."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.main.2008.11.010","article-title":"Nerve transfers in brachial plexus palsies","volume":"28","author":"Oberlin","year":"2009","journal-title":"Chir. Main"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"137","DOI":"10.4103\/ijps.IJPS_31_17","article-title":"Correlation of compound muscle action potential generated by donor nerves with the recovery of elbow flexion in Oberlin transfer in brachial plexus injury","volume":"51","author":"Thatte","year":"2018","journal-title":"Indian J. Plast. Surg."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/7\/2476\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T13:45:36Z","timestamp":1774359936000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/7\/2476"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,24]]},"references-count":43,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["jcm15072476"],"URL":"https:\/\/doi.org\/10.3390\/jcm15072476","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,24]]}}}