By Harry A. Bade, III, MD, FACS
Burner’s syndrome, also known as "stingers,” is an acute peripheral nerve injury involving the upper trunk of the brachial plexus nerves, which is formed by the C5 and C6 nerve roots exiting from the cervical spine. It is characterized by immediate and severe burning pain along with the sensation of prickly paresthesias and numbness that radiates from the upper shoulder or supraclavicular area extending circumferentially to the shoulder, lateral arm and at times, to the forearm, wrist, hand and fingers.
It follows no specific nerve root innervations of the skin or dermatomes. This is an injury to the pain fibers of the peripheral nerve root. There are also motor fibers within the peripheral nerve root, which causes a concomitant weakness of the involved extremity. This weakness involves mainly the muscles that rotate and flex the shoulder but also the biceps muscle, which flexes the elbow and twists the forearm into a palm-up position.
The pain is usually transient, lasting seconds or greater than five or maybe ten minutes. The motor weakness is longer lasting and needs an initial evaluation followed by follow-up evaluations to correctly estimate the extent of nerve injury. In the majority of cases motor power returns to normal again within several minutes. Occasionally, motor power will not return for days or even weeks, or may become more severe with an increased loss of strength and rarely may become permanent with the severest of injuries.
This injury is commonly seen in collision or contact sports such as football, ice hockey, wrestling, and rugby. The incidence is rather high involving between 50 and 65% of collegiate football players. It is probably higher because there is also a high incidence of nonreporting by these same collegiate football players. In football it occurs most commonly in the linebackers and smaller defensive backs while tackling. It may also occur with running backs or linemen while blocking or being tackled. There is also a very high incidence of recurrence, which must be addressed by the medical staff to minimize this problem.
The mechanism of injury is usually traction occurring with a substantial direct blow to the lateral shoulder pad, depressing the lateral shoulder at the same time the neck or cervical spine is pushed or tilted in the opposite direction. A second type of injury occurs from a direct contusion to the brachial plexus or supraclavicular fossa. This occurs from a direct blow, which may cause the edge of the shoulder pads to come in contact with the brachial plexus. The final mechanism is a compression-flexion combination that occurs with a combination of the shoulder being flexed and the neck being hyper-extended and rotated toward the injured shoulder.
The injuries are graded as I, II or III. Grade I injuries are transient loss of nerve function or motor power, lasting from hours to at most two weeks. With this, there is both edema and demyelination of the nerve axon which repairs itself within two to three weeks. Grade II injuries exhibit motor weakness that lasts for longer than two weeks with usually 80 to 90% recovery by six weeks and full strength returning at six months. Grade III injuries are continued motor weakness after one year or permanent motor weakness.
Electrodiagnostic testing to include EMG studies are done after three weeks. They will likely be positive in a Grade II injury or multiple Grade I injuries. Repeat EMG studies can monitor the recovery or healing of the nerve and muscles.
Treatment is best left to skilled medical personnel to include athletic trainers, emergency medical staff and sports medicine physicians. It is important to document the history and physical examination of the initial and all recurrent stingers. An athlete may return to his sport when he is pain-free, muscle strength is vastly improved and adequate to protect him (4+/5), the recovery has occurred over a short period of time (ten to fifteen minutes) and additional protection is afforded the athlete, which is initially the application of at least a neck roll.
To avoid recurrent injuries, which occur in at least 50 to 60% of the athletes, it should begin with an immediate reevaluation of the athlete’s equipment, i.e. shoulder pads and helmet. The helmet must fit properly and an extension of the face mask can protect cervical motion. The addition of a cowboy collar has been found to be better than a neck roll to limit cervical motion. In recurrent conditions, both the cowboy collar and neck roll should be considered.
Proper blocking and tackling technique should be addressed by the coaching staff. Maintenance of proper strength involving the cervical and scapular rotator muscles is necessary and should be continued in the off season. A strengthening program for the deltoid, biceps, supraspinatus and infraspinatus rotator cuff muscles should be initiated immediately. Shoulder pads can also be lifted upwards with additional padding beneath the shoulder pads, which are termed either lifters or spider pads.
More severe injuries necessitate appropriate medical evaluation and referral to appropriate medical experts. This includes emergency personnel, sports medicine specialists, orthopaedic surgeons or even neurologists. The burner syndrome is from the shoulder down and does not involve the cervical spine. Cervical spine pain with stiffness may possibly be a more serious injury and should be treated appropriately. A player should not return to action if he has continued cervical pain.
Symptoms into both arms or radiation into both legs is also a more significant injury probably of the cervical spine. Weakness lasting several days or progressive weakness is also more serious, or a history of recurrent burners with each becoming symptomatic for longer periods of time. Congenital spinal stenosis, herniated intervertebral discs, fracture, cervical sprain or strain, if considered, must be appropriately protected and ruled out by standard medical evaluation.