Pavlov-Torg ratio : A/B <0.8 indicative of congenital stenosis
Presentation and Evaluation
The diagnosis of a stinger is a clinical diagnosis that is made by history and physical examination. Most athletes will experience one of the three aforementioned mechanisms of injury and then present to the medical staff immediately after the offending play. If the player is able to leave the field of play under his or her own strength, then a sideline evaluation is appropriate. If the player is unable to leave the field of play, then evaluation should proceed on the field. Regardless of where the initial evaluation is performed, the most important and critical aspect of the evaluation should be recognizing any red flag symptoms that suggest a more serious spinal cord injury. In general, it is exceedingly rare for a stinger to affect more than one extremity. When a player presents with pain, weakness, or paresthesias in multiple extremities, then the evaluating medical staff should suspect a spinal cord injury until proven otherwise. Additional red flag symptoms include cervical spine pain, tenderness to palpation along the cervical spine, pain with any attempted movement of the cervical spine, abnormal reflexes, deformity, localized swelling, difficulty breathing, or changes in vision or mentation. These symptoms should prompt an emergent neurological evaluation along with full spine precautions. The player should be placed on a spine board with removal of any face mask to allow for airway management if needed. The player should be immediately transferred to the emergency room via ambulance for imaging of the entire spine and further care whenever a more serious spinal cord injury is suspected. However, in the setting of isolated upper extremity symptoms without any red flag symptoms, the initial diagnosis of a stinger may be presumed.
Athletes with a stinger will often grab the affected extremity or hold it in an elevated position with the opposite arm in order to reduce tension on the cervical nerve roots. The athlete will commonly report a burning pain or sensation that starts around Erb’s point and shoots down the entire arm. Paresthesias and sensory loss may or may not be present and may present in either a circumferential or dermatomal pattern. Isolated upper extremity weakness is often present in various degrees, yet weakness can also present in a delayed fashion or not at all, depending on the severity of injury. The athlete will generally present with full and painless cervical spine range of motion without tenderness to palpation.
Once the diagnosis of a stinger is made, a neurological examination should be performed on the sideline. The examination should include palpation of the cervical spine followed by strength testing of all muscle groups, sensory evaluation of all dermatomes, and assessment of deep tendon reflexes. The unaffected extremity can be used as a point of reference to help detect any subtle weakness. The examiner should pay special attention to weakness with arm abduction, shoulder external rotation, and elbow flexion as these actions are largely controlled by the C5 and C6 nerve roots. A shoulder examination should also be performed to assess for shoulder instability or any other abnormality to the clavicle, acromioclavicular joint, or sternoclavicular joint. Erb’s point can also be percussed, which may elicit radiating pain.
If the patient denies any neck pain and has no tenderness to palpation of the cervical spine, then neck range of motion may be assessed in flexion, extension, lateral bending, and rotation. Range of motion should only be tested when a more serious spine injury has been sufficiently ruled out as outlined above. Lastly, a Spurling’s maneuver may be performed. This test has been found to be positive in up to 70% of patients with a stinger [7].
Serial examinations are very important in the assessment of a player with a stinger because the symptoms tend to be transient and evolve over time. Symptoms from a stinger may last for only a few minutes or up to days, weeks, or even months. The majority of stingers will resolve within minutes or hours. Though less common, weakness may present in a delayed fashion after normal strength on the initial examination, which further heightens the importance of serial assessments. Additionally, if serial examinations reveal worsening neurological signs or symptoms, then the evaluating staff should re-evaluate for the presence of any red flag symptoms and act accordingly.
Management and Work-Up
Initial management requires removal from competition, rest, and pain control. A sling may be used for comfort in the setting of persistent upper extremity weakness. Treatment of a stinger is largely symptomatic, and most stingers will resolve quickly without intervention. First-time stingers that resolve rapidly do not require any further management or treatment. However, when an athlete has persistent symptoms that preclude return to play, a comprehensive rehabilitation program should be initiated. The program should focus on cervical spine and upper extremity range of motion, appropriate posture, proprioception, and lastly muscle strengthening. Neuromuscular coordination is also a very important component of the rehabilitative process following a stinger.
The role of cervical spine imaging and electrodiagnostic studies after a stinger is controversial. Routine cervical spine radiographs following every stinger are typically not recommended. Players who sustain a first-time stinger with rapid resolution of symptoms do not require cervical spine imaging or diagnostic tests. Commonly suggested indications for imaging work-up include persistent symptoms beyond 1 h, concomitant neck pain, symptoms localized to only one nerve root, or recurrent stingers [16, 24, 25]. The initial test of choice is cervical spine radiographs because they are obtained quickly and provide valuable diagnostic information. Specifically, radiographs can identify fracture, foraminal stenosis, or instability on flexion and extension views. The next imaging study obtained should be a MRI, especially in the setting of persistent weakness [24]. A cervical spine MRI can further define any neuroforaminal stenosis, nerve root injury, spinal cord edema, disc herniation, or disc-osteophyte complexes that may be contributing to neuroforaminal stenosis. MRI is especially important in the evaluation of chronic or recurrent stingers since these are both frequently associated with foraminal narrowing and cervical disc disease.
Electrodiagnostic testing can be considered in the athlete with persistent symptoms, though the information obtained typically does not guide treatment options. In general, electrodiagnostic testing is more helpful in evaluating muscle weakness than sensory symptoms. It can also help localize the site of injury by differentiating a cervical nerve root injury from a brachial plexus injury. Additionally, electrodiagnostic testing can help differentiate a neuropraxic injury from an axonal injury, which can help guide prognosis and time frame for recovery.
In general, electrodiagnostic testing should rarely be considered within 3 weeks of the injury because signs of denervation are not present before this time point. Furthermore, findings on electrodiagnostic testing can remain abnormal even after the athlete has sustained a full clinical recovery of strength [26]. Therefore, these tests should only be performed in patients with persistent weakness on exam at least 3 weeks after the injury. Any radicular pattern of injury seen on electrodiagnostic tests should also be further evaluated with an MRI if one has not been previously obtained.
Return to Play
Return to play criteria following a stinger can be controversial. The decision to withhold an athlete from competition is largely dependent on the examination, on history of previous stingers, and sometimes on results of advanced imaging [16, 17, 25, 27, 28]. No athlete should be allowed to return to play until he or she has complete resolution of neurological deficits, including return of full strength and sensation. Any degree of persistent neurological deficit is an absolute contraindication to return to play. Additionally, the athlete should have full, pain-free cervical spine range of motion, no neck tenderness to palpation, and no suspicion for underlying cervical injury. If symptoms resolve rapidly and the athlete meets the above criteria, he or she may be considered for return to play in the same game in the setting of a first-time stinger.
A first-time stinger with persistent symptoms is a contraindication to return to play in the same game. When symptoms from a stinger persist beyond approximately 1 h, then cervical spine imaging should be obtained. Any evidence of neck pain also precludes return to play in the same game and requires the patient to undergo further imaging work-up. Absolute contraindications for return to play include persistent weakness, cervical anomalies or pathology on advanced imaging, continued pain, evidence of cervical myelopathy, and reduced cervical range of motion.
While return to play after a first-time, rapidly resolving stinger is generally accepted as safe, return to play in the setting of a recurrent stinger can be quite controversial and is largely dependent on the timing and severity of the recurrence. A second stinger that occurs in a separate season with rapid resolution and a normal examination is an indication for return to play in the same game. A recurrent stinger in the same game or season, even with rapid resolution of symptoms, precludes return to play in the same game. The decision to return to play for the following game depends on the persistence of symptoms. After a second, rapidly resolving stinger in the same game or season, the athlete may return the following game with or without cervical spine imaging. However, if symptoms are persistent after a second stinger, then the player should be withheld from physical activity, and cervical spine imaging should be obtained.
A third stinger, regardless of timing, is a contraindication to return to play . These athletes must undergo cervical spine imaging if it was not obtained after the second stinger [29]. Management of an athlete with a third stinger is also controversial but typically involves removing the athlete from competition for the remainder of the season. These athletes have a high prevalence of cervical spine stenosis and other anomalies that place them at a higher risk for future spinal injuries [6, 7, 13, 14]. The treating medical staff should have extensive discussions with the athlete and consider restricting the athlete from future participation in contact sports, especially when advanced imaging reveals cervical spine anomalies.
Advanced imaging and electrodiagnostic testing usually play a supportive role when making return to play decisions. These tools can be helpful when evaluating an athlete’s risk for future stingers, but they should not be used in isolation when determining return to play status for an athlete. Even if cervical spine imaging is within normal limits, the athlete should not return to competition if any neurological symptoms persist. Furthermore, cervical spinal stenosis has been associated with a higher risk of experiencing a stinger, but it is also quite prevalent in elite football and rugby players who have not obtained stingers [23].
Similarly, abnormal electrodiagnostic findings should not preclude progression of rehabilitation or return to play in the setting of a normal neurological examination. In fact, abnormal findings on electrodiagnostic tests may persist even after full clinical neurological recovery [18]. Therefore, advanced imaging is most helpful within the context of an athlete’s history and current physical examination findings.
Return to play guidelines following a stinger
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