Prior to considering surgery, a detailed and careful assessment must be completed. Coulet et al. (2002) recommended assessing the following;
The extent of LMN injury at the injured metamere must be assessed and each key muscle group evaluated to determine:
- Type of motor neuron injury (LMN, UMN) by evaluating tone, trophic status, deep tendon reflex
- Joint range of motion and deformities
- Electrodiagnostic studied are beneficial to determine extent of SCI
After a careful and complete evaluation, Coulet et al. (2002) recommended mapping the muscles to identify three the following:
- Functional muscles (innervated by supralesional segments)
- Paralyzed and denervated muscles (innervated by injured metamere with damage to LMN)
- Paralyzed but innervated muscles (innervated by infralesional segment, with preserved LMN)
The next assessment to be made is to decide what primary function to be restored. Kozin (2002) recommended the following priority: 1) restoration of elbow extension; 2) pinch restoration for hand function; and 3) grasp and release function.
Nerve transfers should be performed after a re-innervation window, to allow adequate waiting time to ensure optimal spontaneous recovery has been achieved for lesional level myotomes. Bertelli et al. (2011) recommended waiting at least 6 months. Re-innervation of muscle innervated by infralesional segment is not time-dependent and can performed years after injury (Bertelli et al. 2011).