Cervical spinal stenosis with cord neurapraxia: evaluations and decisions regarding participation in athletics

Cervical spinal cord neurapraxia (CCN) leads to transient episodes ranging from paresthesia to paresis to plegia (complete paralysis), and occurs in athletes with some demonstrable degree of cervical spinal stenosis. Determination of spinal stenosis requires demonstrating a sagittal diameter of the spinal canal less than 14 mm from C4 to C6. Because radiologic techniques vary affecting the accuracy of this measure, a ratio method was developed comparing the spinal canal to the vertebral body width, demonstrating that a ratio of less than 0.8 is indicative of cervical spinal stenosis. Although this has high sensitivity (93%), the low predictive value of 0.2% makes this a poor screening tool for athletic participation. Further complicating the challenge of determining which athletes are at risk for quadriplegia are data showing that athletes who suffered permanent injury did not recall transient episodes of CCN, and conversely none of the athletes with CCN later developed permanent neurologic injury. Nevertheless, 56% of football athletes returning to sport after an episode of CCN experienced a recurrence as determined by survey data. Those with CCN and documented ligamentous instability, magnetic resonance imaging evidence of cord defects or swelling, neurologic symptoms or signs for greater than 36 hours, or more than one recurrence have an absolute contraindication.