Tendon transfer for Radial Nerve Palsy

By:Dr.mohammed Abd-Alhussein Laftah

Plastic surgery residentBaghdad university –Alkindy college of medicine

• Radial nerve losses are divided into high and low nerve disruptions.

• Low lesions: are essentially posterior interosseous palsies, without loss of wrist extension. They demonstrate:

1. loss of thumb extension–abduction and 2. loss finger extension at their

metacarpophalangeal (MCP) joints, the intrinsic muscles providing interphalangeal extension.

• High lesions:demonstrate the losses of low nerve lesions with

the addition of total loss of active wrist extension as a result of paralysis of the extensor carpi radialis longus (ECRL) and brevis (ECRB).

Anatomy- Innervation Order of Muscles: Radial Nerve• BR• ECRL• Supinator*• ECRB

• EDC• ECU• EDM• APL• EPL• EPB• EIP

Main radial nerve

posterior interosseous nerve

Requirements in a Patient with Radial Nerve Palsy

• A patient with irreparable radial nerve palsy needs to be provided with

(1) wrist extension.(2) finger (metacarpophalangeal [MP] joint)

extension.(3) a combination of thumb extension and

abduction.

Amplitude of Motion

The surgeon must also have some appreciation of the amplitude of tendon excursion for each Muscle:

• Wrist flexors and extensors: 33 mm• Finger extensors and EPL: 50 mm• Finger flexors: 70 mmThese above-listed values have practical significance because it is impossible for a wrist

flexor with an excursion of 33 mm to substitute fully for a finger extensor that requires an amplitude of 50 mm. Although the true amplitude of tendon excursion cannot be increased, two things can be done to augment its effective amplitude.

First:the natural tenodesis : the effective amplitude of the tendon is increased significantly by active volar flexion of the wrist, allowing the transferred wrist flexor to extend the fingers fully

second factor: that can increase amplitude is extensive dissection of the• muscle from its surrounding fascial attachments. This is particularly true of the BR.

Historical Review

• Jones is credited with being the major innovator of radial nerve transfers, and all the article in the post–World War I era acknowledged his fundamental contributions.

Jones Transfers

--• PT to ECRL and ECRB• FCU to EDC III-V• FCR to EIP, EDC II, • PT to ECRL and ECRB• FCU to EDC III-V• FCR to EIP, EDC II, EPL, EPB, and APL

Best Combinations of Tendon Transfers for Radial Nerve Palsy

FCR transfer • PT to ECRB• FCR to EDC• PL to rerouted EPLSuperficialis Transfer :• PT to ECRL and ECRB• FDS III to EDC• FDS IV to EIP and EPL• FCR to APL and EPBFCU Transfer• PT to ECRB• FCU to EDC• PL to reroute EPL

Operative technique

Incisions used in the FCU combination of transfers

PT to ECRB transfer. It is important to take a strip of periosteum in continuity with PT insertionto ensure adequate length for transfer

FCU to EDC transfer. FCU must be freed up extensively to create a direct line of pull from itsorigin to the new insertion into EDC tendons just proximal to dorsal retinaculum. End-to-side juncture isshown here. Moberg and Nachemson suggested that 4 to 5 cm of paralyzed EDC tendons be resected proximal to the juncture, allowing an end-to-end suture and a more direct line of pull

Draw back of FCU transfer

(1) The FCU is too strong and its excursion is too short for transfer to the finger extensors.

(2) its function as the prime ulnar stabilizer of the wrist is too important to sacrifice.

PL to rerouted EPL transfer. By rerouting EPL out of dorsal retinaculum, the transfer creates acombination of abduction and extension force on thumb.

CRITICAL POINTS: TENDON TRANSFERS

FCU to EDC▪ Do not use for tendon transfer in posterior interosseous nerve palsy.▪ The FCU must be freed up extensively, requiring a long incision.▪ Generously excise muscle from the distal half of the tendon to reduce bulk.▪ Free up the muscle sufficiently to allow it to be redirected obliquely across theforearm.▪ Protect the muscle's innervation in the proximal muscle belly.▪ Create a line of pull from the medial epicondyle to the EDC as straight as possible.▪ Tendon juncture: weave the FCU through the EDC tendons at a 45-degree anglejust proximal to the dorsal retinaculum.▪ Include the EDM only if there is a lag in extension of the small finger.▪ Tension:▪ Wrist in neutral (0 degrees)▪ MP joints in neutral (0 degrees)▪ FCU under maximum tension

CRITICAL POINTS: TENDON TRANSFERS

PL to Rerouted EPL▪ Transect the EPL at its musculotendinous junction.▪ The EPL tendon is rerouted to pass along the radial border of

the thumb metacarpal.▪ The tendon juncture of PL to EPL is in the snuffbox superficial

to the dorsal retinaculum in line with the thumb metacarpal.▪ Tension:▪ Wrist in neutral (0 degrees)▪ Maximum tension on distal stump of EPL▪ PL under maximum tension

CRITICAL POINTS: TENDON TRANSFERS

PT to ECRB▪ Take a strip of periosteum from the radius in continuity with the PT

insertion.▪ Free up the muscle proximally to gain maximum excursion.▪ Pass the tendon around the radial border of the forearm superficial to

the BR and ECRL.▪ Suture only into the ECRB—do not include the ECRL—just distal to the

musculotendinous junction.▪ Tension:▪ Wrist in 45 degrees of extension▪ PT under maximum tension▪ Reinforce juncture with a strip of free tendon graft.

Flexor Carpi Radialis Transfer

FCR to EDC transfer. Brand suggested that EDC tendons be transected and transposedsuperficial to dorsal retinaculum to create a straight-line, end-to-end juncture with FCR

Flexor Carpi Radialis Transfer • A straight longitudinal incision is made in the distal half of the volar radial aspect ofthe forearm between the FCR and PL. Both tendons are identified, transected near theirinsertions, and freed up to the middle of the forearm to allow redirection of the tendons totheir new insertions.• A second longitudinal incision is made on the dorsum, extending from just distal to the

dorsal retinaculum to the mid-forearm.• The FCR is passed around the radial border of the forearm through a subcutaneous tunnel.• The juncture between the FCR and EDC can be made by: 1. Leaving the EDC in continuity (similar to the FCU transfer depicted in Figure).2. the EDC tendons be divided so that a formal end-to-end suture can be done between the

FCR and EDC, as shown in Figure. To avoid the problem of multiple exposed raw tendon ends, burying each cut tendon end.

• The finger extensor tendons all are tested for extension of the MP joint, and “four good tendons are chosen.” These are divided at their musculotendinous junctions; withdrawn distally, superficial to the intact dorsal retinaculum; and redirected to a point over the distal radius, where they can meet the FCR tendon in a straight line.

CRITICAL POINTS: FCR TO EDC

▪ Divide the FCR near its insertion and pass it subcutaneously around the radial border of forearm.

▪ Divide the EDC tendons just proximal to the retinaculum, and reposition the stumps superficial to the retinaculum.

▪ Tension:▪ Wrist in neutral (0 degrees)▪ MP joints in neutral (0 degrees)▪ FCR under maximum tension

Superficialis Transfer

• two finger superficial flexor muscles, not their tendons, can be brought through the interosseous membrane, using one for the thumb and the other for the combined fingers.

Postoperative Management

a long arm splint is applied that• immobilizes the forearm in 15 to 30degrees of pronation.• the wrist in approximately 45 degrees of extension.• the MP joints in slight (10 to 15 degrees) flexion.• the thumb in maximum extension and abduction. • The proximal interphalangeal joints of the fingers are left free. The cast is removed 4 weeks postoperatively; removable short

arm splints to hold the wrist, fingers, and thumb in extension are made, which the patient wears for an additional 2 weeks, removing them only for exercise.

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