gms | German Medical Science

Objectives/Interrogation: Transfer of contralateral C7 nerve has been successfully applied to reconstruct motor function of affected upper limb in chronic central neurological injury. However, in certain patients, finger extension still remains difficult. One possible mechanism is the fiber distribution of C7. The flexor carpi radialis (FCR) is mainly innervated by C7 nerve. The FCR muscle branch can be used to transfer the posterior interosseous nerve (PIN) to increase the independent control of the finger extensor muscle group. This study was designed to test the effectiveness of FCR branch transfer to PIN.

Methods: Two patients were enrolled in the study. The first is a 48-year-old man who had severe spasticity and hemiplegia in both upper and lower limbs on the right, 29 months after a left cerebral hemorrhage and 17 months after contralateral C7 transfer.

The second patient is a 19-year-old man who suffered from permanent muscle weakness in his right wrist and finger extension 8 years after left cerebral arteriovenous malformation rupture, with little spasticity. Both patients underwent right FCR branch to PIN tranfer to improve finger extension 1 year after contralateral C7 nerve transfer. Motor function of lower limb was assessed preoperatively and postoperatively.

Results and Conclusions: One year after surgery, the first patient experienced transient significant decrease of wrist and finger spasticity lasting for 2 months, and gradually back to the baseline. Both patients regained finger extension in an extremely relaxed state but failed in tension state. Motor function of wrist flexion was not impaired by transferring FCR branch.

In conclusion, although more nerve fibers from contralateral C7 nerve entered PIN, the functions of the finger extension were not significantly improved. It suggested that improving the independent control of finger extension for hemiplegic patients may require more attention to the inhibition from the tensor of flexion.