Nerve Transfer Reconstruction in the Tetraplegic Upper Extremity

Overview

The cervical spine is most commonly injured, accounting for 53.4% of spinal injuries. More than 40% of all spinal injuries occur at either C4, C5 or C6 levels leading to variable loss of function in the upper extremities. Traditionally, patients sustaining a cervical spine injury were followed for 2 years to ensure that recovery had stabilized before offering upper extremity reconstruction. This type of reconstruction includes active muscle transfer, tendon transfer and joint fusion. Patients are most commonly assessed immediately at the time of injury. Muscle testing is commonly performed using Medical Research Grading System (MRC). Although complete neurologic stabilization may not be complete until 2 years post-injury, in the group with initial grade 0 muscle strength after the acute phase of injury, expectations of improved muscle strength to or beyond grade 3 after 4-6 months is minimal. And grade 3 muscle strength is felt to be the minimum useful functional strength in a muscle group. The investigators propose an early nerve reconstruction approach to the tetraplegic patient with dysfunction of the upper extremity to augment the available tendon transfers. A comparative pilot study is proposed to determine the effectiveness of supinator branch to posterior interosseous nerve (PIN) transfer in 5 patients with cervical spine injury. Patient who fits inclusion criteria will be offered the opportunity to be involved in the study and reviewed at 6 months from injury. If the patient still has not regained Grade 3 power in finger or thumb extension, they will be randomized to be in a surgical group or non-surgical group. If informed consent is obtained, then surgery will be completed between 6-9 months from the patient's original cervical spine injury. The patient will be followed at regular intervals post-operatively with expectation of 18-24 month follow-up. Measures will be used pre and post-operatively for comparison. Measures will include MRC muscle grade (EDC), range of motion, Disability of the Arm, Shoulder, and Hand Questionnaire (DASH), and The Graded Redefined Assessment of Strength Sensibility and Prehension (GRASSP) (Kalsi-Ryan, 2011).

There is currently no published data showing the effect of early nerve transfer on hand function recovery of the subset of tetraplegic patients, who have initial grade 0 muscle strength immediately after their injuries. We are interested in conducting a pilot study comparing the surgical group to the non-surgical group. A larger trial will be planned if the preliminary results show positive improvement in hand function recovery.