Friday, November 9, 2007

Tendon Transfers Used in Radial Nerve Palsy

Following high radial nerve paralysis

  • the wrist needs an extensor (photo credit)
  • the fingers and thumb need extensors
  • the carpometacarpal joint of the thumb needs an extensor to replace the abductor pollicis longus

Most authors agree that tendon transfers provide good results if nerve reconstruction fails in patients with radial nerve palsy. There is continued disagreement on the best combination of tendon transfers to use in treating patients with radial nerve paralysis. The level of the radial nerve injury and a patient’s overall function and anatomy should be kept in mind when choosing the best surgical option available for that patient.

In 1916, Robert Jones described a tendon transfer for radial nerve palsy that included the pronator teres to the wrist radial extensors, the flexor carpi radialis to the extensors comminis, and the flexor carpi ulnaris to extensor indicis and pollicis longus. The transfer of both wrist flexors has since been abandoned by most surgeons because of the excess morbidity from the loss in wrist flexion.

Most authors agree that the extensor carpi radialis brevis and longus should be reconstructed using the pronator teres tendon. This transfer is so effective that it is often done at the time of nerve repair. It provides good wrist stability for power grip, making the hand useful even during the recovery period. Try flexing your wrist and then keeping your wrist flexed while trying to make a fist, as you would in a power grip to open a jar, etc. It is very difficult, almost impossible to have a true power grip without wrist extension or neutral position. (photo credit)

To provide extension for the fingers, it is best to use a wrist flexor as this is synergistic with finger extension. At one time it was common to transfer all wrist flexors in the case of radial palsy, but Zachary pointed out the need to keep stability on the flexor side too. Boyes emphasized the importance of keeping the flexor ulnaris in its position to give the important movement of ulnar deviation. There is no one "great" transfer here. The extensor digitorum communis can be reconstructed using the flexor digitorum superficialis (III), the flexor carpi ulnaris, or the flexor carpi radialis. The rerouted extensor pollicis longus can be reconstructed using the palmaris longus or the flexor digitorum superficialis (IV), and, in some cases, the abductor pollicis longus and extensor pollicis brevis can be reconstructed with the flexor carpi radialis. Dr. Susan MacKinnon prefers to use the pronator teres to the extensor carpi radialis brevis, the flexor carpi ulnaris to the extensor digitorum communis, and the palmaris longus rerouted to the extensor pollicis longus (when available); otherwise, we use the flexor digitorum superficialis. (photo credit)


Burkhalter also advocated early tendon transfer because he believed the transfer acts both as a substitute during regrowth of the nerve or when lesions are irreparable and also as a helper during reinnervation. In a recent article, Kruft et al. reported that irreversible radial nerve paralysis should be treated with early tendon transfer. They reported 43 patients who underwent tendon transfer, with 38 patients ultimately returning to their original jobs. The authors qualified their results by stating that tendon transfers “never fully replace an intact radial nerve for the purpose of controlling the hand.” Elton and Omer observed that patients with radial nerve paralysis treated by tendon transfer often experienced extensor tightness, which prevented simultaneous flexion of the wrist and fingers. Barton described this as a “rather unnatural movement, seldom needed in ordinary life.” Many authors have thought that the greatest functional loss after radial nerve palsy was not the loss of finger extension, but instead the loss of power grip, which cannot be easily recreated with standard tendon transfers.

References

Current Approach to Radial Nerve Paralysis; Plastic & Reconstructive Surgery. 110(4):1099-1113, September 15, 2002; Lowe, James B. III, M.D.; Sen, Subhro K. M.D.; Mackinnon, Susan E. M.D.

Tendon Transfers for Radial Nerve Palsy-- Wheeless' Online Textbook of Orthopaedics

Atlas of Hand Surgery By Sigurd Pechlaner--Google eBook (very nice pictures of the transfers)

The Hand: Fundamentals of Therapy By Judith Boscheinen-Morrin, W. Bruce Conolly--Google eBook

Radial Nerve Entrapment by Mark Stern, MD--eMedicine article

1 comment:

Chris said...

I'm receiving a patient who had a deep laceration to his wrist, and my buddy at the base in Mosul described his injury as "Spaghetti wrist" because all the tendons were out. I've never heard this before. It might not be a clinical term because he can get a little colorful! Take care, C