“Following brachial plexus injury, it is almost always possible to restore some useful function from nerve repair, nerve transfer, and/or secondary repair but almost never possible to restore full function”

The brachial plexus is a network of nerves that arise from the cervical spinal cord and provide motor, sensory and vegetative supply the entire upper extremity including muscles attaching the upper extremity (scapula) to the torso.  

This is a schematic representation of the right human brachial plexus. It receives contributions from the nerve roots C5 to T1, and some anatomical variations from C4 or T2 as well. Injury to the brachial plexus may be open transection (also known as rupture, usually in stab or gunshot injury) or closed stretch injuries (high velocity vehicle accidents). The latter may lead to avulsion of one, more or all contributing roots. The surgical procedure aims at either reestablishing the lost continuity of the brachial plexus elements (nerve suture with or without nerve grafts) or rerouting compensable nerves within or without the brachial plexus to gain important motor function (nerve transfer). Thorough knowledge of normal and pathological anatomy as well as modern technology such as intraoperative nerve monitoring and mapping are indispensable for recognizing each distorted element and restoring their continuity. Such primary reconstruction is best done within weeks after injury.

Brachial plexus injuries occur as a rule after motorcycle, snowboard, skiing and other high velocity accidents and cause total or partial loss of function of the arm plus spontaneous pain associated with avulsion of cervical spinal nerve roots. The loss of function and pain can be devastating. They require special consideration in treatment because of the complex anatomy, the probability that some of the injury is due to avulsion of spinal nerve roots from the spinal cord rather than disruption of peripheral nerves, and the propensity to severe chronic pain.

Evaluation of the injury and decisions regarding treatment are through clinical examination, MR imaging (particularly to detect spinal nerve root avulsions) and electrophysiological testing both pre-operatively and intra-operatively.

 Three surgical strategies are available to restore function after brachial plexus injury.

Three surgical strategies are available to restore function after brachial plexus injury.

(1) Direct repair of disrupted elements of the brachial plexus is best undertaken within weeks of the injury.

This is a case study of a pateint with complete brachial plexus palsy after a motorbike accident with a combined stretch and crush mechanisms to the brachial plexus. Exploration and intraoperative mapping showed rupture of the upper and middle roots (C5-C7) and avulsion of the C8 root. T1 was found intact. Surgical strategy consisted of direct repair using nerev grafts as well as a single nerve transfer from the end branch of the spinal accessory to the suprascapular nerve.

This is another case study of a extended upper brachial plexus palsy occurring after a snowbike accident associated with stretch injury to the left shoulder. Exploration and electrophysiological monitoring during surgery showed severe traction to the C5-C7 roots , rendering their remnants functionally useless, although there was no evidence of avulsion. Recosntruction of the brachial plexus was through nerve transfers, where the spinal accessory and intercostal nerves served as axonal donors to regain useful biceps and shoulder functions.

(2) Nerve transfer, with sacrifice of a dispensable or compensable nerve to regain an important movement such as shoulder abduction or elbow flexion is usually undertaken 3-6 months after injury but may sometimes be successful after a year or more.

(3) Secondary functional reconstruction with tendon transfer, muscle transfer, or free muscle transfer can be undertaken years or even decades after the initial injury. Such surgery on tendons and muscles is necessary in 50-60% of cases to improve the results of nerve surgery. The principle of secondary functional reconstruction is to regain a completely lost, important function (e.g., elbow flexion) by providing a new motor across that joint, either using functionally intact muscles of the anatomical neighborhood (e.g., the flexor pronator group of the forearm) or from distant places of the human body (free functional muscle transfer). An essential condition for the success of any secondary functional reanimation is the maintenance of a supple joint, which can be mobilized passively through a full range of movement.