Cervical Stenosis
Robert D. Menzies
L. Shay Richardson
BasicsDescription
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A congenital or acquired narrowing of the cervical spinal canal. However, this problem has several definitions. This definition is based on MRI evidence from the National Center for Catastrophic Sports Injury Research (NCCSI).
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Functional spinal stenosis is the loss of the CSF cushion around the spinal cord or a clear deformation of the cord demonstrated by CT scan, MRI, or myelography.
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Synonym(s): Cervical cord neurapraxia; Any transient neurologic deficits
Epidemiology
Incidence
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The incidence of cervical stenosis is unknown.
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However, Torg reported that in a single football season, 6 of 10,000 exposures resulted in transient paresthesia in all 4 extremities and 1.3 of 10,000 exposures resulted in transient quadriplegia (1).
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This describes cervical cord neurapraxia (CCN), which is thought to be a sequela of stenosis.
Prevalence
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In a cadaveric study, Lee et al. estimated the prevalence of cervical spinal stenosis to be 4.9% of the adult population based on radiographic measurement of canal diameter <12 mm (2).
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Cervical stenosis also was found to increase with age.
Risk Factors
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Congenital or acquired defects, which include bulging disk, hypertrophied or unstable ligaments, and degenerative changes
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Involvement in sports that engage in potential axial loading, such as football, ice hockey, diving, head-first sliding in baseball, wrestling, soccer, gymnastics, and rugby
DiagnosisHistory
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During preparticipation physical examination, determination of any prior history of neurologic events, such as burners/stingers or transient neurologic events, is critical.
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If the athlete gives a positive response, all data from previous evaluations must be reviewed. If no workup has been done, then seriously consider starting one before allowing the athlete to begin contact/collision sports.
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If the athlete has a condition such as Down syndrome, odontoid abnormality, atlantooccipital fusion, or Klippel-Feil anomaly, these may predispose him or her to cervical stenosis, and the athlete must be further evaluated.
Physical Exam
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Unfortunately, cervical stenosis is asymptomatic until forced hyperflexion or hyperextension occurs with an axial load, which causes CCN.
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The athlete develops acute transient sensory paresthesia and/or motor paresis.
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Findings are always bilateral.
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Paresthesia is described as burning pain, numbness, or tingling of the affected region.
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Motor changes can range from weakness to complete paralysis.
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Neurapraxia commonly lasts 10–15 min but can take up to 48 hr to resolve (3).
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During the preparticipation physical examination, the Spurling foraminal compression test can be done. If symptoms are elicited, further workup can be started. The yield is very low unless the patient already has stenosis. It should be done on any athlete who gives a history of neurologic events.
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If the initial event occurs on the field, start with assessment of the athlete's level of consciousness. If unconscious, immobilize and transport. If conscious, proceed to assess neck pain.
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If neck pain is present or absent and the athlete has neurologic symptoms, immobilize and transport for further workup.
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Diagnostic Tests & Interpretation
Imaging
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The initial radiographic examination should start with cervical spine x-rays, which can be used to evaluate for gross fracture or dislocation. In addition, some measurements of the spinal canal can be done. The normal canal measures >15 mm; <13 mm is considered spinal stenosis (4).
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On the lateral x-ray, the Torg ratio can be calculated. Measure (in millimeters) the distance from the posterior aspect of the vertebral body to the spinolaminar line (a) and the width of the vertebral body (b); then calculate the ratio a/b. A value <0.8 is abnormal and needs further evaluation (5).
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A large vertebral body can result in a false-positive result; the false-positive rate has been reported as high as 88%. If the patient has spinal stenosis, the ratio almost always is abnormal.
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Cervical x-ray limitations include the failure of roentgenography to appraise the width of the cord and an inability to appreciate stenosis resulting from ligamentous hypertrophy, ligamentous laxity, or disk protrusion.
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Therefore, the next step is to use MRI or CT myelography.
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MRI can evaluate spinal stenosis caused by most abnormalities. It is not as effective as CT myelography in evaluating bony lesions. MRI is sufficient in most cases (4,6).
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MRI is done in a neutral position. With hyperextension, spinal canal diameter decreases by 30% owing to infolding of the interlaminar ligaments.
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“Functional” spinal stenosis, defined as loss of CSF around the cord or, in more extreme cases, deformation of the spinal cord, whether documented by CT myelography, MRI, or standard myelography, is a more accurate measure of stenosis (4,6).
Differential Diagnosis
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Stable spinal fracture
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Any cause of permanent spinal cord injury
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Spear tackler's spine
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Unstable fracture
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Spinal fracture with dislocation
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Ligamentous injury
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Herniated cervical disk
P.75
TreatmentAdditional Treatment
Additional Therapies
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After the 1st episode of CCN, if the initial workup is negative for stenosis, a generalized neck strengthening program should be started.
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Athletes involved in collision sports should be able to support their body weight with the cervical spine in neutral and in all directions when positioned at a 45-degree angle.
Surgery/Other Procedures
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If an acquired cause for spinal stenosis is detected, consultation with a neurosurgeon or orthopedic spine surgeon for consideration of surgery can be undertaken.
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However, after surgery, the athlete probably cannot participate in contact/collision sports.
Ongoing CareFollow-Up Recommendations
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Team physicians should be concerned with functional spinal stenosis. If present, and the athlete incurs spinal cord symptoms, the athlete should not continue in contact/collision sports because such activities predispose athletes to a worse neurologic outcome in the context of cervical spine injuries (4,6).
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Data collected by the NCCSI from 1987 to 1996 showed that no athlete with functional spinal stenosis and cervical spinal fracture recovered from quadriplegia.
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This finding needs to be compared with nearly 20% of athletes with cervical spinal fracture and normal canal sizes who had initial quadriplegia and recovered fully.
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During the same period, in all cases of quadriplegia without cervical spinal fracture dislocation, severe spinal stenosis was present.
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If the athlete redevelops CCN, the workup should proceed again, from plain radiographs to MRI or CT myelography.
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According to a review performed by Torg et al., 56% of National Football League players with one episode of CCN went on to develop a repeat episode after return to play (3).
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Given the excellent sensitivity of the Torg ratio, any athlete with an abnormal ratio along with spinal cord symptomatology should undergo MRI, myelography, or CT myelography (4).
References
1. Torg JS, Pavlov H, et al. Neurapraxia of the cervical spinal cord with transient quadriplegia. J Bone Joint Surg. 1986;21:1354–1370.
2. Lee Michael J, et al. Prevalence of cervical spine stenosis: Anatomic study in cadavers. J Bone Joint Surg. 2007;892:376–380.
3. Eddy, Derrick, et al. A review of spine injuries and return to play. Clin J Sports Med. 2005;15(6):453–458.
4. Cantu RC. Cervical spine injuries in the athlete. Semin Neurol. 2000;20:173–817.
5. Torg JS. Cervical spinal stenosis with cord neurapraxia and transient quadriplegia. Clin Sport Med. 1990;9:279–296.
6. Cantu RC. The cervical spinal stenosis controversy. Clin Sport Med. 1998;17:121–126.
7. Cantu RC. Stingers, transient quadriplegia, and cervical stenosis: return to play criteria. Med Sci Sports Exerc. 1997;29[7 Suppl]:233–235.
Additional Reading
Cantu RC, Bailes JE, Wilberger JE Jr. Guidelines for return to contact or collision sport after a cervical spine injury. Clin Sport Med. 1998;17:137–146.
Maroon JC, Bailes JE. Athletes with cervical spine injury. Spine. 1996;21:2294–2299.
Wilberger JE Jr. Athletic spinal cord and spine injuries. Clin Sport Med. 1998;17:111–120.
Zachazewsia JE, Magee DJ, Quillen WS. Athletic injury and rehabilitation. Philadelphia: WB Saunders, 1996.
CodesICD9
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723.0 Spinal stenosis in cervical region
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742.59 Other specified congenital anomalies of spinal cord
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756.10 Congenital anomaly of spine, unspecified
Clinical Pearls
Return-to-play guidelines (7):
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Canal/vertebral body ratio ≤0.8 in asymptomatic individuals: No contraindication
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Ratio of ≤0.8 with one episode of CCN: Relative contraindication
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Documented episodes of CCN associated with intervertebral disk disease and/or degenerative changes: Relative contraindication
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Documented episode of CCN associated with MRI evidence of cord defect or cord edema: Relative/absolute contraindication
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Documented episode of CCN associated with ligamentous instability, symptoms, or neurologic findings lasting >36 hr and/or multiple episodes: Absolute contraindication
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Any episode in which, during the evaluation, functional stenosis is detected: Absolute contraindication
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Athletes with significant bone or ligamentous spinal instability, spinal cord contusion, or significant spinal stenosis should not return to contact sports.