Radial Nerve Injury

INTRODUCTION

Radial nerve is the continuation of the posterior cord of the brachial plexsus with a root value of C5-C8 T1.it supplies all three heads of triceps, anconeus ,brachialis, brachioradialis, extensor carpii radialis longus and brevis and supinator muscles.through the posterior interosseous nerve it supplies the remaining muscles of the forearm and abductor pollicis longus muscle

The radial nerve is extended from the nerve root in the neck, and supplies sensations and movements to the parts of upper extremities.  Radial nerves are a commonly damaged nerves by trauma or external compression.

PATHOPHYSIOLOGY:

Nerve injury secondary to compression or traction depends on intensity and duration.4

Seddon has classified nerve injuries into 3 categories17:

The first, neuropraxia, is a transient episode of motor paralysis with little or no sensory or autonomic dysfunction. No disruption of the nerve or its sheath occurs. With removal of the compressing force, recovery should be complete.

The second, axonotmesis, is a more severe nerve injury with disruption of the axon but with maintenance of the Schwann sheath. Motor, sensory, and autonomic paralysis results. Recovery can occur if the compressing force is removed in a timely fashion and if the axon regenerates.

The third, neurotmesis is the most serious injury. The nerve and its sheath are disrupted. Although recovery may occur, it is never complete, secondary to loss of nerve continuity.

Sunderland has classified nerve injury into 5 categories4:

The first is similar to neuropraxia.

The second is similar to axonotmesis.

The third, fourth, and fifth degrees correspond to varying degrees of neurotmesis.

CAUSES:

Trauma — radial nerve injuries often occur with a humerus (upper arm bone) fracture.  Because the radial nerve passes through the furrow on the surface of the humerus, it is easily damaged when the humerus is broken.  Radial nerve palsy can easily occur with a fracture of the forearm.

Nerve compression by an anatomical structure surrounding the radial nerve.

External compression of the radial nerve — after sleeping with an arm over the back of a chair, the patient experiences a drop in the wrist, tingling, and numbness of the forearm and hand.  This form of radial nerve palsy is known as “Saturday night palsy.”

Local causes:in the axilla due to aneurysm of the axillary vessels, crutch palsy. In the shoulder proximal humerus fracture and shoulder dislocation. In the spiral groove shaft fracture, saturday night palsy, syringe palsy, tourniquet palsy. Between spiral groove and lateral epicondyle fracture shaft humerus, supracondylar fracture fracture humerus, fracture of lateral epicondyle, cubitus valgus deformity, gunshot injury. At the elbow fracture head of radius, posterior dislocation of elbow, monteggia fracture. At forearm fracture of radius and ulna.

SYMPTOMS:

Numbness and a reduction of felt sensations on the back surface of the forearm and hand

Tingling sensation or pain of the affected upper extremity

Wirst drop — the patient cannot extend the wrist and fingers outward when the palm is in a downward position

DIAGNOSIS:

IMAGING STUDIES:

Radiographs

In a suspected entrapment of the radial nerve in the arm, obtain radiographs to detect or rule out a fracture, healing callus, or tumor as the cause of entrapment.

MRI

is useful in detecting tumors such as lipomas and ganglions, as well as aneurysms and rheumatoid synovitis.

OTHER TEST:

Electromyographic (EMG) and nerve conduction study results are abnormal in radial nerve injuries in the middle and distal third of the humerus. EMGs help to locate the site of injury and help the clinician monitor the nerve recovery over time. EMGs may not be positive for 3-6 weeks following injury. By 4 months’ postinjury, nerve recovery should be demonstrable. EMG may be performed initially to provide a baseline, but unless the nerve is severed, no changes will be observed for 3-6 weeks.

 

EMG and conduction studies reveal abnormal function of the extensor carpi ulnaris, the extensor digitorum communis, and the extensor digiti quinti. If only the lateral branch is compressed, then abnormal function of the abductor pollicis longus, the extensor pollicis longus and brevis, and the extensor indicis proprius is revealed. The site of compression is localized by all function proximal to the compression being normal and all function distal to the compression being abnormal.

TREATMENT:

In many cases, radial nerve palsy resolves itself.  Recovery may be partial or complete according to the severity of the nerve damage.

Conservative treatment — physical therapy is necessary to minimize the muscle wasting and maximize the muscle function during the recovery period.  A wrist splint or brace may be helpful for the functional use of the hand in dealing with a severe wrist drop.

Surgical decompression is necessary for prolonged radial palsy due to compression by an anatomical structure.

If the radial nerve function does not return within several months after a humerus fracture, or if radial nerve palsy occurs with an open fracture of the humerus, then surgical exploration is recommended.

Tendon transfer technique

 

PHYSIOLINE’S SPECIALIZED PHYSIOTHERAPY HAS VITAL ROLE TO PLAY

At Physioline, all the members of the rehabilitation team work together so as to provide proper care and the therapy in order to: