Recovery of Motor Function after Mixed and Motor Nerve Repair with Processed Nerve Allograft

Abstract

Background: Severe trauma often results in the transection of major peripheral nerves. The RANGER Registry is an ongoing observational study on the use and outcomes of processed nerve allografts (PNAs; Avance Nerve Graft, AxoGen, Inc., Alachua, Fla.). Here, we report on motor recovery outcomes for nerve injuries repaired acutely or in a delayed fashion with PNA and comparisons to historical controls in the literature.

Methods: The RANGER database was queried for mixed and motor nerve injuries in the upper extremities, head, and neck area having completed greater than 1 year of follow-up. All subjects with sufficient assessments to evaluate functional outcomes were included. Meaningful recovery was defined as ≥M3 on the Medical Research Council scale. Demographics, outcomes, and covariate analysis were performed to further characterize this subgroup.

Results: The subgroup included 20 subjects with 22 nerve repairs. The mean ± SD (minimum-maximum) age was 38 ± 19 (16-77) years. The median repair time was 9 (0-133) days. The mean graft length was 33 ± 17 (10-70) mm with a mean follow-up of 779 ± 480 (371-2,423) days. Meaningful motor recovery was observed in 73%. Subgroup analysis showed no differences between gap lengths or mechanism of injury. There were no related adverse events.

Conclusions: PNAs were safe and provided functional motor recovery in mixed and motor nerve repairs. Outcomes compare favorably to historical controls for nerve autograft and exceed those for hollow tube conduit. PNA may be considered as an option when reconstructing major peripheral nerve injuries.

Fig. 1.

Injury and repair of an ulnar nerve with PNA. A, 16-year-old girl presented to the clinic in a delayed fashion with a low ulnar nerve palsy after accidental laceration to the left forearm with a pocket knife. Surgical exploration 41 days after injury, the flexor carpi ulnaris and ulnar neurovascular bundle was nearly completely transected and encased in tremendous amount of scar. B, Neurolysis of the ulnar nerve and resection to healthy fascicles resulting in a gap length of 23 mm. C, Following repair using two 3–4 mm diameter PNA in a grouped fascicular fashion.

Fig. 2.

Recovery of motor function in subject with the ulnar nerve injury 481 days after repair. A, Recovery of finger abduction. B, Reinnervation of the hypothenar muscles allowing the fifth digit opposition with the thumb. C, Recovery of finger metacarpal-phalangeal joint flexion and interphalangeal joint extension of the small and ring fingers.

Fig. 3.

Distribution of MRC motor scores.

Video Graphic 1

. See video, Supplemental Digital Content 1, which displays motor functional outcomes at 16 months postulnar nerve reconstruction with PNA. This subject presented to the clinic in a delayed fashion with a low ulnar nerve palsy after accidental laceration to the left forearm with a pocket knife, http://links.lww.com/PRSGO/B12.