CC BY 4.0 · J Brachial Plex Peripher Nerve Inj 2023; 18(01): e1-e5
DOI: 10.1055/s-0042-1760097
Original Contribution

Outcomes after Anterior Interosseous Nerve to Ulnar Motor Nerve Transfer

1   Division of Plastic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
Steven E. Dawson
1   Division of Plastic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
Gerald J. Wu
1   Division of Plastic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
Scott Loewenstein
2   Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
Gregory H. Borschel
1   Division of Plastic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
Joshua M. Adkinson
1   Division of Plastic Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
› Author Affiliations
Funding None.


Background Ulnar nerve lesions proximal to the elbow can result in loss of intrinsic muscle function of the hand. The anterior interosseous nerve (AIN) to deep motor branch of the ulnar nerve (DBUN) transfer has been demonstrated to provide intrinsic muscle reinnervation, thereby preventing clawing and improving pinch and grip strength. The purpose of this study was to evaluate the efficacy of the AIN to DBUN transfer in restoring intrinsic muscle function for patients with traumatic ulnar nerve lesions.

Methods We performed a prospective, multi-institutional study of outcomes following AIN to DBUN transfer for high ulnar nerve injuries. Twelve patients were identified, nine of which were enrolled in the study. The mean time from injury to surgery was 15 weeks.

Results At final follow-up (mean postoperative follow-up 18 months + 15.5), clawing was observed in all nine patients with metacarpophalangeal joint hyperextension of the ring finger averaging 8.9 degrees (+ 10.8) and small finger averaging 14.6 degrees (+ 12.5). Grip strength of the affected hand was 27% of the unaffected extremity. Pinch strength of the affected hand was 29% of the unaffected extremity. None of our patients experienced claw prevention after either end-to-end (n = 4) or end-to-side (n = 5) AIN to DBUN transfer.

Conclusion We conclude that, in traumatic high ulnar nerve injuries, the AIN to DBUN transfer does not provide adequate intrinsic muscle reinnervation to prevent clawing and normalize grip and pinch strength.

Informed Consent

Witten informed consent was obtained from all subjects before the study.

Ethical Approval

Ethical approval for this study was obtained from Indiana University Health Institutional Review Board (#10180)

Publication History

Received: 28 July 2022

Accepted: 07 September 2022

Article published online:
11 January 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

  • References

  • 1 Polatsch DB, Melone Jr CP, Beldner S, Incorvaia A. Ulnar nerve anatomy. Hand Clin 2007; 23 (03) 283-289
  • 2 Valone JA. Paralysis of the ulnar nerve and management of its deformity. J Neurosurg 1953; 10 (02) 138-144
  • 3 McCormick CA, Rath S, Patra PN, Pereira J, Wilkinson M. A qualitative study of common functional problems experienced by people with complete ulnar nerve paralysis. Lepr Rev 2008; 79 (02) 154-161
  • 4 Bertelli JA. Prior to repair functional deficits in above- and below-elbow ulnar nerve injury. J Hand Surg Am 2020; 45 (06) 552.e1-552.e10
  • 5 Gaul Jr JS. Intrinsic motor recovery–a long-term study of ulnar nerve repair. J Hand Surg Am 1982; 7 (05) 502-508
  • 6 Sakellarides H. A follow-up study of 172 peripheral nerve injuries in the upper extremity in civilians. J Bone Joint Surg Am 1962; 44-A: 140-148
  • 7 Ruijs AC, Jaquet JB, Kalmijn S, Giele H, Hovius SE. Median and ulnar nerve injuries: a meta-analysis of predictors of motor and sensory recovery after modern microsurgical nerve repair. Plast Reconstr Surg 2005; 116 (02) 484-494 , discussion 495–496
  • 8 Millesi H, Meissl G, Berger A. The interfascicular nerve-grafting of the median and ulnar nerves. J Bone Joint Surg Am 1972; 54 (04) 727-750
  • 9 Loewenstein SN, Adkinson JM. Tendon transfers for peripheral nerve palsies. Clin Plast Surg 2019; 46 (03) 307-315
  • 10 Wang Y, Zhu S. Transfer of a branch of the anterior interosseus nerve to the motor branch of the median nerve and ulnar nerve. Chin Med J (Engl) 1997; 110 (03) 216-219
  • 11 Brown JM, Yee A, Mackinnon SE. Distal median to ulnar nerve transfers to restore ulnar motor and sensory function within the hand: technical nuances. Neurosurgery 2009; 65 (05) 966-977 , discussion 977–978
  • 12 Novak CB, Mackinnon SE. Distal anterior interosseous nerve transfer to the deep motor branch of the ulnar nerve for reconstruction of high ulnar nerve injuries. J Reconstr Microsurg 2002; 18 (06) 459-464
  • 13 Sallam AA, El-Deeb MS, Imam MA. Nerve transfer versus nerve graft for reconstruction of high ulnar nerve injuries. J Hand Surg Am 2017; 42 (04) 265-273
  • 14 Flores LP. Comparative study of nerve grafting versus distal nerve transfer for treatment of proximal injuries of the ulnar nerve. J Reconstr Microsurg 2015; 31 (09) 647-653
  • 15 McLeod GJ, Peters BR, Quaife T, Clark TA, Giuffre JL. Anterior interosseous-to-ulnar motor nerve transfers: a single center's experience in restoring intrinsic hand function. Hand (N Y) 2022; 17 (04) 609-614
  • 16 Arami A, Bertelli JA. Effectiveness of distal nerve transfers for claw correction with proximal ulnar nerve lesions. J Hand Surg Am 2021; 46 (06) 478-484
  • 17 Kettle SJ, Starritt NE, Glasby MA, Hems TEJ. End-to-side nerve repair in a large animal model: how does it compare with conventional methods of nerve repair?. J Hand Surg Eur Vol 2013; 38 (02) 192-202
  • 18 Rönkkö H, Göransson H, Taskinen HS, Paavilainen P, Vahlberg T, Röyttä M. Comparison of peripheral nerve regeneration with side-to-side, end-to-side, and end-to-end repairs: an experimental study. Plast Reconstr Surg Glob Open 2016; 4 (12) e1179
  • 19 Tateshita T, Ueda K, Kajikawa A. End-to-end and end-to-side neurorrhaphy between thick donor nerves and thin recipient nerves: an axon regeneration study in a rat model. Neural Regen Res 2018; 13 (04) 699-703
  • 20 Chen SH, Mao SH, Lan CY. et al. End-to-side anterior interosseous nerve transfer: a valuable alternative for traumatic high ulnar nerve palsy. Ann Plast Surg 2021; 86 (2S, Suppl 1) S102-S107
  • 21 Schenck TL, Stewart J, Lin S, Aichler M, Machens HG, Giunta RE. Anatomical and histomorphometric observations on the transfer of the anterior interosseous nerve to the deep branch of the ulnar nerve. J Hand Surg Eur Vol 2015; 40 (06) 591-596
  • 22 Snyder-Warwick AK, Fattah AY, Zive L, Halliday W, Borschel GH, Zuker RM. The degree of facial movement following microvascular muscle transfer in pediatric facial reanimation depends on donor motor nerve axonal density. Plast Reconstr Surg 2015; 135 (02) 370e-381e
  • 23 Rafuse VF, Gordon T. Incomplete rematching of nerve and muscle properties in motor units after extensive nerve injuries in cat hindlimb muscle. J Physiol 1998; 509 (Pt 3): 909-926
  • 24 Methot J, Chinchalkar SJ, Richards RS. Contribution of the ulnar digits to grip strength. Can J Plast Surg 2010; 18 (01) e10-e14