Peripheral Nerve Injuries - Robert Lee 31/3/2005

Basic Principles and Considerations

Classification of nerve injuries

·          Seddon: Neuropraxia, axonotmesis and neuronotmesis ( Seddon: Three types of nerve injury. Brain 66:237, 1943 )

·          Sunderland’s more elaborate classification: Grades 1-5 ( Sunderland : A classification of peripheral nerve injuries – producing loss of function. Brain 74:791, 1951 )

·          Both are often misunderstood and misused.   The distinction between axonotmesis and neuronotmesis or between Sunderland grades 3,4 and 5 can only be made by the passage of time or by direct inspection of the nerve.  

·          Thomas and Holdorff ( Neuropathy due to physical agents. In Dyck and Thomas (eds): Peripheral Neuropathy, 3 ^rd Ed. Philadelphia, Saunders p990, 1991 ).

It is better to think of nerve lesions as degenerative or nondegenerative :

• Focal conduction block

• Transient (ischaemic/other)

• More persistent (demyelinating/axonal constriction)

• Axonal Degeneration

• With preservation of basal laminal sheaths of nerve fibres

• With partial section of nerve

• With complete transection of nerve

Primary reasons for operating on peripheral nerves

1. To confirm or establish diagnosis

2. Restore continuity to a severed or ruptured nerve

3. To relieve a nerve of an agent that is compressing, distorting or occupying it

Clinical Diagnosis

In closed lesions the key is understanding the extent and application of force eg an arterial rupture inevitably leads to nerve rupture.   It is assumed that the recovery following #/dislocation is good.  

This is not necessarily true:

·          Seddon: 146 out of 212 lesions in upper limb #/dislocations spontaneously recovered. (Surgical disorders of Peripheral Nerves 2 ^nd Ed Edinburgh. Churchill Livingstone 1975)

·          Omer:   83% of injuries from closed upper limb # recovered ( Injuries to nerves of the upper extremity. JBJS Am 56: 1615, 1974 )

·          Both showed that if a nerve was going to recover it showed clear evidence at no later than 3 months

·          Kato and Birch ( presented BSSH 2004 : Outcomes in closed fractures):178 palsies – graded recovery into excellent/good/fair/poor

• Prognosis for good outcome:

• Low-energy injury

• Advance or absence of Tinel’s sign

• Electophysiological evidence of the conduction block

• Early onset of nerve recovery

• No neuropathic pain

• Results

• Median and Ulnar >90% good/excellent

• Radial: 68% good/excellent

• Circumflex: 66% good/excellent

• Common peroneal: 43% good/excellent

Radial Nerve

·          Shah and Bhatti : 62 palsies in humeral # . 95% recovered normal or near normal function. Indications for early surgery - unacceptable # reduction, open #, and vascular injuries.   If no evidence of recovery, the nerve should be explored. Except in unequivocal irreparable radial nerve damage, tendon transfers should be deferred for at least 6 months, preferably for one year. The possible effect of entrapment of nerve by scar and callus remains to be established.   (Radial nerve paralysis associated with fractures of the humerus. A review of 62 cases. Clin Orthop 1983 Jan-Feb;(172):171-6)

·          Shergill: 242 repairs of radial nerve. 30% good results and 28% fair. 42% failed. Failure associated when defect greater than 10 cms and when high force of injury.   Repair with 14 days – 49% good. Later than 14 days only 28% good. (The radial and PIN: results of 260 repairs. JBJS B 83: 646, 2001)

Nerve injuries following hip arthroplasty

·          Incidence varies from 0.3% to 3% fro Sciatic Nerve (Calandruccio in Campbell ’s operative orthopaedics). Schmalzreid and Amstutz found overall incidence of major nerve palsy to be 1.7%. (Nerve injury and total hip arthroplasty. In Gelberman (ed): Operative Nerve Repair and Reconstruction. Philadelphia, Lippinoctt p1245, 1991)

·          Consequences: Oldenburg and Muller: only one third recover. 2713 arthroplasties. Overall incidence of 2.24% rising to 8.5% in acetabular revisions. (The frequency, prognosis and significance of nerve injuries in total hip arthroplasty. Int Orthop, 21.1, 1997)

Brachial Plexus Injuries

Birch R.   Brachial plexus injuries. J Bone Joint Surg [Br] 1996; 78-B:986-92.

·          Incidence: 450-500 patients suffer severe and permanent from closed supraclavicular lesions per year (Goldie and Coates. J Hand Surg Br. 17:76, 1992)

·          Majority less than 25 yrs, Dominant limb in 60%, 1/3 remain unemployed after injury, 2/3 in severe pain 1 year from injury (Rosson. Injury 19:4, 1988)

Treatment

·          Avulsion C5 to T1: Treatment is nerve transfer to reinnervate suprascapular and long thoracic nerve and lateral cord. Results of intercostals transfer: In 179 pts: Full elbow function in 80% but replicated by European Surgeons. (Nagano A, Tsuyama N, Ochiai N, Hara T, Takahashi M.   Direct nerve crossing with the intercostal nerve to treat avulsion injuries of the brachial plexus. J Hand Surg 1989; 14-A:980-5)

·          Rupture C5 to C6 (C7), avulsion (C7) C8/T1