Outcomes of Reverse End to Side Nerve Transfer for Severe Ulnar Nerve Injury: A Western Canadian Prospective Multicentre Case Controlled Study
Matthew WT Curran, MD, MSc, Plastic and Reconstructive Surgery, Princess Alexandra Hospital, Woolloongabba, QLD, Australia; Plastic and Reconstructive Surgery, Brisbane Hand and Upper Limb Research Institute, Spring Hill, QLD, Australia, Jaret Olson, MD, Plastic and Reconstructive Surgery, University of Alberta, Edmonton, AB, Canada, Michael Morhart, MSc, MD, Department of Plastic and Reconstructive Surgery, University of Alberta, Edmonton, AB, Canada, Simon Wu, B.Sc, University of Alberta, Edmonton, AB, Canada, Rajiv Midha, MD, Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada, K. Ming Chan, MD, Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, AB, Canada and Michael James Berger, MD, PhD, FRCPC, CSCN Diplomate (EMG), University of British Columbia, Division of Physical Medicine and Rehabilitation, Vancouver, BC, Canada
Introduction:Severe high ulnar nerve injuries often carry poor outcomes after surgery. Anterior interosseous (AIN) reversed end to side (RETS) nerve transfer has been proposed as a promising technique. The purpose of this prospective multicentre case controlled study was to compare the physiological and functional outcomes of high ulnar nerve patients after AIN ETS compared to AIN ETE or nerve decompression alone.
Methods:Patients with severe axon loss from high ulnar nerve injury were divided into 3 groups: RETS, ETE or decompression at the elbow. In the nerve transfer groups, decompression was also done at Guyon's canal. Electrophysiology measures were used to quantify the regeneration of AIN and ulnar nerve fibres to the intrinsic hand muscles while functional recovery was evaluated using key pinch strength. Between-group comparisons at baseline and recovery in each group were tracked post-surgically at regular intervals over 3 years.
Results:Sixty patients (RETS n=25; ETE=15; decompression n=20) from four centres in Western Canada were enrolled. All patients had nerve compression at the elbow except 10 patients in the ETE group had high ulnar nerve laceration or traction injury. At baseline, the extent of axon loss was more severe in the ETE compared to the other 2 groups. Post-surgically, no axonal growth from the AIN to the hypothenar muscles was seen in any of the RETS patients while significant regrowth was found in all ETE patients with corresponding functional improvement. While there was no significant improvement in CMAP amplitudes in the decompression and RETS group, key pinch strength significantly improved in the RETS group but not in the decompression group.
Conclusions: Although ETE nerve transfer results in significant physiological and functional improvements, the treatment is only applicable to patients with severe or complete axonal loss injury. While there was no significant motor reinnervation following RETS, the key pinch strength nevertheless improved. The underlying explanation for this will require further investigation.
Back to 2022 Abstracts