The Effects of Operative Delay on the Relief of Neuropathic Pain after Injury to Brachial Plexus

Author(s): Kato N, Htut M, Taggart M, Carlstedt T, Birch R

Source: J Bone Joint Surg 88-B: 756-750, 2006.

Summary:

Pre-ganglionic injury of the brachial plexus typically provokes a constant crushing or burning pain.  This pain is extremely recalcitrant to treatment.  Severe pain is much less frequent after post-ganglionic rupture.  Relief of pain by successful nerve repair has been reported.  This study attempts to establish whether delay or immediate repair influences pain relief.  The patient cohort consisted of two groups of patients with at least one spinal nerve suffering a pre-ganglionic injury.  Confirmation was obtained by CT, MRI, or absent central conduction when the spinal nerve was stimulated at operation.  The study group consisted of a prospective and a retrospective group.  There were a total of 148 patients with at least one avulsion included in the study.  There were 136 males and 12 females with an average age of approximately 25 years.  Nerves were repaired by grafting, transfer, or reimplantation of nerve roots (only 4 patients).  The patients were divided into four groups based on the interval between injury and exploration.  Group 1 was defined as one month from injury and consisted of 61 patients; group 2 was defined as a delay between one to three months after injury and consisted of 29 patients; group 3 was late and defined as three to six months after injury and consisted of 32 patients; and group 4 was considered neglected, which was defined as more than six months after injury (26 patients).

There were two patterns of pain reported.  The first type consisted of constant pain in the insensible hand, usually described as crushing, burning and bursting.  The second type consisted of shooting pain always felt in the dermatome of the injured spinal nerve.  One hundred and eight patients took some type of analgesic medication for more than six months.  Even marijuana was used and helped in 30 patients.  There was a correlation between the severity of nerve injury (# of avulsions) and subsequent pain.  Interestingly, a shorter time interval between injury and nerve repair led to a greater improvement in neuropathic pain.  Following treatment, the mean visual analogue scale for pain was most diminished in the early group.  Functional assessment after repair showed a good recovery 30% of the time, 50% of the time fair and 19% of the time poor. 

Pain after pre-ganglionic lesions is often one of the most important obstacles in rehabilitation.  This study attempts to analyze the correlation of nerve repair and pain.  The major finding was that a shorter interval between injury and repair led to a greater improvement in pain.  Both the visual analogue scale and peripheral nerve injury scale were less with early repair.  Another interesting finding was a trend whereby more avulsions with a higher degree of pain.  The reasoning behind severe pain after pre-ganglionic injuries remains unclear.  The fact that early nerve repair would be beneficial is similar to the response after peripheral neuromas that are grafted.  Although the functional assessment was pessimistic, pain was improved.  This may lend further support for early exploration and repair following severe brachial plexus lesions.

 

Brachial, Plexus, Palsy, Repair, Pain, Neuropathic


Related Links
J Bone Joint Surg