Radial Nerve Injury

• The Jones/Tsuge/Boyd modified transfer for high radial nerve palsy requires the presence of a palmaris longus and two fully functional wrist flexors.

• The Jones/Tsuge/Boyd transfer does not provide independent finger extension.

• The Jones/Tsuge/Boyd modified transfer may cause mild ulnar deviation of the wrist.

the brachioradialis, as well as no response to the extensor digitorum communis, extensor pollicis longus, as well as to the extensor carpi radialis brevis (ECRB).

Differential Diagnosis

Tendon laceration extensor pollicis longus (EPL) Tendon laceration ECRB, extensor carpi radialis longus (ECRL) Radial nerve palsy Mixed nerve palsy

Diagnosis

High Radial Nerve Palsy

The physical examination and diagnostic studies necessitated a discussion about a high radial nerve palsy without any good prognosis for recovery.

Radial nerve injuries that occur in the proximal one third of the forearm result in a low radial nerve palsy (Fig. 23—2). Low radial nerve palsies are characterized by loss of thumb extension, abduction, and finger extension, and by lack of grasp. The level of injury can also be diagnosed by the "hanging of the wrist." If the wrist is straight, the level is above the elbow. If the wrist is extended but radial deviated (ECRL intact), the level of injury is below the elbow.

The radial nerve originates on the posterior cord of the brachial plexus, just above the axilla. The nerve passes posteriorly and laterally in close approximation to the

Radial Nerve Trauma Radial Nerve Damage
Figure 23—2. Anatomy of radial nerve as it crosses the elbow to branch into the posterior interosseus nerve (PIN).
Radial Nerve Course
Figure 23—3. Anatomy of the volar and dorsal forearm essential for understanding successful transfer of the tendons in a radial nerve palsy.

humerus throughout its course. The nerve is protected by the long and lateral heads of the triceps. Fractures, such as a displaced spiral oblique fracture, can severely damage the nerve in this area. The sensory branch of the radial nerve becomes subcutaneous underneath the brachioradialis in the distal forearm. The radial nerve provides motor branches to the triceps, brachioradialis, and supinator, and the wrist, finger, and thumb extensors (Fig. 23—3). The radial nerve provides sensory innervation to the posterior and inferolateral arm, posterior forearm, and dorsal radial wrist and hand.

The treatment of fractures with associated radial nerve palsy is controversial. An EMG that revealed a nonfunctioning brachioradialis at 4 months from the date of injury may require, as was done, a nerve exploration. Nerve exploration may reveal a stretched and contused radial nerve that may be lacerated as well, presumably by the fracture (bone spicules). Now with no recovery, the hand and wrist function will be restored with tendon transfers.

Nonsurgical Treatment

Observation is indicated in some nerve palsies associated with fractures. Since return of normal function can be anticipated at 3 to 6 months, surgical management should be undertaken at this time.

Surgical Management

Preoperative planning is essential for all operative cases, but especially for those involving tendon transfers. The principles for tendon surgery must be adhered to prior to any successful tendon transfer. Principles such as one donor for wrist extension, one donor for finger extension, and one donor for thumb extension must be strictly adhered. Passive range of motion of the wrist and fingers must always be maintained, as described in our conservative treatment, prior to any elective tendon transfer with preoperative wrist extension splinting all completed prior to the day of surgery.

There are many options for high radial nerve palsy. This transfer is a modified Jones/Tsuge/Boyd:

1. Pronator teres to ECRB

2. Flexor carpi radialis to the finger extensors [extensor digitorum communis (EDC)]

3. Palmaris longus to extensor pollicis longus

4. Tenodesis of abductor pollicis longus

These donor muscles are preferred as they preserve power grip by leaving the flexor carpi ulnaris intact and do not use the flexor digitorum superficialis. On the other hand, this transfer requires two excellent wrist flexors and the palmaris longus. If these tendons are not present, this transfer cannot be used and an alternative must be selected.

A skin incision is made at the junction of the upper and middle thirds of the radial side of the forearm and extends distally to approximately 3.0 cm proximal to the radial styloid. The incision moves dorsally to the fourth dorsal compartment. A short transverse incision is made just proximal to the volar wrist flexion crease over the flexor carpi radialis and the palmaris longus insertion to identify these structures.

The pronator teres is identified at the insertion of the midshaft of the radius on the dorsal aspect of the forearm and is detached from the 3.0-cm strip of periosteum. The muscle is then freed proximally to the midline of the forearm. It is essential that slow and meticulous dissection occurs, as the 3.0-cm strip of the periosteum is quite necessary to maintain length when attempting to suture this strip into the ECRB (Fig. 23-4).

With the palmaris longus and the flexor carpi radialis transected at the wrist and freed proximally to the midforearm, both tendons are moved dorsally through a

Pronator Teres Transfer
Figure 23—4. Clinical photo of pronator teres prepared for transfer to the extensor carpi radialis brevis (ECRB). (Photo courtesy ofS. Kozin)
Palmaris Longus Transfer Epl
Figure 23—5. (A) The flexor carpi radialis (FCR) tunneled subcutaneously into the dorsal aspect of the forearm to meet the common finger extensors. (B) The palmaris longus tunneled to meet the extensor pollicis longus (EPL) on the dorsum to allow for thumb extension.

subcutaneous dissection opened up with a hemostat (Fig. 23—5). The ECRB is cut at the midforearm, and the wrist is held at 50 to 60 degrees of extension. The pronator teres is then sutured to the ECRB without tension (Fig. 23-6). The wrist should move into ~30 degrees of wrist dorsiflexion when placed against gravity at rest and flexion with the tenodesis effect. The remaining part of the procedure, that is finger extension and thumb extension, is now completed. If prior to beginning finger extension and thumb extension the wrist has a slight position of ulnar deviation due to the loss of the flexor carpi radialis, suturing must occur on the distal end of the ECRL with some tension to the distal aspect of the ECRB to compensate.

The extensor digitorum communis as well as the extensor minimi quinti are cut at the midforearm level. It is important to not include the extensor indicis proprius in this transfer. The flexor carpi radialis is split and sutured to each tendon separately. The tendon length is checked by using the tenodesis effect with palmar flexion of the wrist, and observation of full finger extension. With the wrist in full dorsiflexion, each finger should be able to flex fully to a position of function.

The third compartment of the wrist is open, and the extensor pollicis longus is freed up. The tendon is cut ~5.0 to 7.0 cm proximal to the radial styloid and sutured to the palmaris longus with the thumb metacarpophalangeal joint in 20 degrees of flexion and the wrist in 30 degrees of extension.

The distal end of the abductor pollicis longus (APL) is looped around the brachial radialis just proximal to the radial styloid. The APL is then sutured to

Radial Tunnel Syndrome

Figure 23—6. Suturing the pronator teres totheECRB.

itself and the brachial radialis with the first metacarpal held in extension, and the wrist in 30 degrees of full extension. This tenodesis effect is completed to make certain no restricted wrist motion is seen (Fig. 23-7). If full ulnar deviation of the wrist is restricted by the tenodesis effect, the APL is loosened to the appropriate tension.

The tourniquet that was used at the beginning of the procedure is let down. Hemostasis is obtained and the wounds are closed. The arm is placed in a volar splint that holds the wrist at ~45 to 50 degrees of dorsiflexion. The finger should be positioned with 30 degrees of palmar flexion at the metacarpophalangeal (MP),

Figure 23—7. The distal abductor pollicis longus (APL) sutured to itself for a tenodesis effect (see text).

Figure 23—7. The distal abductor pollicis longus (APL) sutured to itself for a tenodesis effect (see text).

Distal Radius Ecrb Ecrl
Figure 23—8. The completed tendon transfer for a patient with high radial nerve palsy.

proximal interphalangeal (PIP), and distal interphalangeal (DIP), and the thumb is placed in abduction with 30 degrees of flexion at the MP and interphalangeal (IP) joints (Fig. 23-8).

Postoperative Management

After approximately 4 weeks all splints are removed, and a volar custom splint made by a hand therapist is applied with extension slings for the MP joint of the fingers. Active range-of-motion exercises of the fingers are begun at 3 to 4 weeks, and the wrist at 6 weeks. Splinting as protection is done for 8 to 12 weeks postoperatively often yields excellent results.

Alternative Procedures

Patients who develop severe wrist contractures should consider undergoing a wrist arthrodesis rather than a tendon transfer. Patients with multiple nerve injuries and insufficient tendon donors to allow for a transfer should also consider a wrist arthrodesis. Patients who are totally disabled and who do not want surgical intervention can use splints custom-made by a certified occupational hand therapist.

Complications

Complications in correction of high radial nerve palsy are several and include overcorrection, undercorrection, and soft tissue bed problems.

Overcorrection is one of the most common complications in this transfer. Overcorrection of a wrist drop may be due to excessive shortening, that is, too much tension in the transfer. This complication can easily be resolved with testing the hand in the operating room with the tenodesis effect. When overcorrection is present due to adherent tendon transfers, passive palmar flexion of the wrist will be limited. The transfer should be reexplored and the tendons lengthened if not recognized intra-operatively. It is important to note that if the pronator teres was used as a tendon donor, it may prove very difficult to lengthen this transfer at a second return visit to the operating room.

Undercorrection of the wrist drop is usually due to a transfer that has been sutured too long. To test the transfer length, with the patient in a postoperative wrist drop, the patient's forearm is supinated so the ulnar side of the wrist is parallel to the examination table. If active wrist dorsiflexion does not improve, the transfer requires shortening. Shortening the tendon by 1.0 cm can increase dorsiflexion by 15 to 20 degrees. To achieve more dorsiflexion with the pronator teres, the ECRB is sutured more distally. If the wrist can dorsiflex with gravity eliminated, the patient's problem is probably one of muscle imbalance, and not in a technical error such as suturing too long.

Contracture of a soft tissue bed with resultant failure of a tendon transfer can be avoided. Adhering to the general principles of tendon transfers often leads to good results. Restoring function to the wrist, with extension as well as digital extension, in most cases can be achieved with a successful tendon transfers. The severity of the deformity and functional goals need to be discussed preoperatively with the patient prior to undertaking any type of tendon transfer in these complex patients.

Suggested Readings

Boyles JH. Tendon transfers for radial palsy. Bull Hosp Joint Dis 1960;21:97.

Brand PW. The Hand and Upper Limb. In: Lamb, DW, ed. The Paralyzed Hand vol 2, New York: Churchill Livingstone; 1987:190-213.

Goldener JL, Kelly JM. Radial nerve injuries. South Med J 1958;51:873-883.

Riordan DC. Tendon transfers in hand surgery. J Hand Surg [Am] 1983;8:748-753.

Scuderi C. Tendon transplants for irreparable radial nerve paralysis. Surg Gynecol Obstet 1949;88:643-651.

Strickland JW, Kleinman WB. Tendon transfers for radial nerve paralysis. Master Tech Orthop Surg 1998;20:303.

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Responses

  • Patryk Munro
    What is dorsal and volar?
    6 years ago
  • betty tabor
    Does a radial nerve injury affect elbow flexion?
    5 years ago

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