Two types of cervical spinal stenosis have been discussed in the medical literature: an acquired (ie, degenerative) type seen in middle-aged and older patients and a congenital type seen in younger, athletic patients. The normal sagittal diameter in the midcervical spinal canal is between 17 and 18 mm. Absolute stenosis is defined as <10 mm, whereas relative stenosis is <13 mm.1
Acquired cervical stenosis results from age-related degenerative disk and facet disease with associated uncinate process hypertrophy, ligamentum flavum thickening, and buckling of the posterior longitudinal ligament. Congenital spinal stenosis is associated with short pedicles and bony anomalies of the lateral masses and laminae.2
Epidemiology including risk factors and primary prevention
Cervical spondylosis is a frequent finding in asymptomatic adults with prevalence rates of 25% of adults <40 years, 50% of adults >40 years, and 85% of adults over 60 years being reported.3 The prevalence rate of cervical stenosis in the United States adult population, as derived from one large cadaveric study, was estimated to be 4.9%.4 Risk factors for developing cervical stenosis include athletic participation in American football, soccer, rugby, and horseback riding, as well as major trauma and dystonic cerebral palsy.3
Neuronal damage in cervical stenosis is mediated by both mechanical and ischemic insults to the spinal cord. Dynamic shortening of the posterior cord (ie, dorsal columns) in extension may account for early difficulties with gait, balance, and proprioception. Chronic cervical spondylotic myelopathy (CSM) causes both gray and white matter demyelination, creating a preponderance of upper extremity (ie, hand) symptoms. This is because of the somatotopic organization of the cervical spinal cord, which places the cell bodies of the ventral horn motor neurons more laterally and the lateral cortical spinal tracts more medially, making them vulnerable to mechanical compression. Compressed arterioles from the anterior spinal artery contribute to cord ischemia, which produces secondary free radical-mediated cell injury and apoptosis.
Traumatic injuries to the intervertebral disks in younger patients can accelerate the degenerative process. Disk herniations, in particular, may contribute to early spondylosis and kyphotic angulation of the cervical spine as axial loads are shifted to the posterior elements.
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
The progression from cervical spondylosis to stenosis and ultimately CSM is variable and difficult to predict. Many patients experience a relatively benign course of disease with episodic flare-ups of axial neck pain and/or cervical radiculopathy. A prospective long-term cohort study of 199 patients presenting with neck pain or cervical radiculopathy and magnetic resonance imaging (MRI) evidence of cord compression without clinical myelopathy estimated that symptomatic spinal cord compression occurred in 25% of the within a 4 year period at a rate of 6.25% per year.5 Those patients presenting with neurologic deficits that did not spontaneously improve experienced further neurologic decline over time resulting in permanent gait and balance impairment, loss of fine motor skills, and bowel or bladder dysfunction.6
Specific secondary or associated conditions and complications
Axial neck pain is the most common symptom associated with spinal stenosis seen in clinical practice.7 Approximately one third of patients with axial neck pain present with headache, and more than two thirds present with shoulder pain.8 Cervical radiculopathy most commonly affects the C6 and C7 nerve roots in the nonathletic population, whereas stingers and burners affecting the C5 and C6 roots are seen in collision sport athletes (ie, American football and rugby players). Spasticity, bowel/bladder dysfunction, deep venous thrombosis, and decubitus ulcers are seen more frequently in immobilized patients with advanced CSM or those in postoperative recovery and inpatient rehabiliation.
2. ESSENTIALS OF ASSESSMENT
In addition to asking questions regarding pain and numbness, the physician should query patients on subtle changes in gait, balance, and loss of fine motor skills, which may suggest myelopathy. Bowel and bladder dysfunction are typically late manifestations. Physicians caring for collision sport athletes need to inquire about cervical spine range of motion and tackling technique, because early loss of cervical extension and shoulder depression during tackling are associated with an increased risk for cervical neuropraxia and/or nerve root and plexus injury.9,10
Cervical spine range of motion, muscle stretch reflexes, and strength should be routinely tested in all patients suspected of having cervical stenosis. Spurling maneuver may reproduce radicular pain and/or paresthesias, which may be relieved by asking the patient to elevate the affected arm overhead (ie, Bakody sign). Hoffman sign, if present, has been shown to positively correlate with CSM.11 A Babinski sign, ankle clonus, and Lhermitte phenomenon should be documented, if present. Sensory ataxia secondary to posterior column dysfunction is assessed by performing a Romberg test.
A wide-based gait may be observed. The development of a myelopathy hand characterized by loss of dexterity, diffuse numbness, intrinsic muscle wasting, ulnar and flexor drift (ie, a positive finger escape sign), and an inability to grasp and release objects may impair activities of daily living.12,13
In the exceedingly unlikely case of an infectious epidural mass in the cervical spine, laboratory tests, such as C-reactive protein, sedimentation rate, and white blood cell count, may have some clinical utility.
Cervical spine radiographs are useful screening tools in patients with suspected cervical stenosis.14 Historically, the Torg-Pavlov ratio (ie, sagittal diameter of the cervical canal: width of a midcervical vertebral body) has been used to quantify the degree of stenosis. A value <.80 is indicative of stenosis; however, this ratio has been reported to have high false-positive rates and to correlate poorly with the true diameter of the cervical canal, especially in collision sport athletes who have larger vertebral bodies.15-17 A computed tomography myelogram may be indicated in those patients with a contraindication to MRI.
Supplemental assessment tools
Electrodiagnostic testing may be helpful in ruling out other disease states, such as carpal tunnel syndrome, peripheral polyneuropathy, or motor neuron disease (ie, amyotrophic lateral sclerosis).
Early predictions of outcomes
In collision sport athletes, cervical neuropraxia resulting in a transient loss of motor and/or sensory function may last up to 36 hours. Players with underlying stenosis have an increased risk for recurrent episodes of cervical neuropraxia, which may or may not result in irreversible spinal cord injury (SCI).18 In adults with asymptomatic stenosis, the presence of electromyography abnormalities or clinical radiculopathy is associated with the development of CSM.19
For young athletes with spinal stenosis participating in American football, proper tackling technique to help decrease the risk of cervical spine injury has previously been mentioned. The question of whether a young adult with cervical stenosis should play contact sports, such as football, is controversial, knowing that such activity increases the risk of severe neurologic injury. In adults with advanced CSM, pain and/or neurologic dysfunction can render these individuals unemployable.
An ergonomic evaluation of a patient’s workstation can be requested by the physician to promote normal postural alignment when seated and decrease repetitive neck extension, which may exacerbate symptoms.
3. REHABILITATION MANAGEMENT AND TREATMENTS
Available or current treatment guidelines
Treatment guidelines for the nonathletic population with cervical stenosis are largely based on systematic reviews of patients with nonspecific axial neck pain. No single nonoperative intervention has proven superior to another; however, supervised exercise is likely to be more beneficial than treatments which do not employ such an approach.20
There is no consensus regarding return-to-play (RTP) guidelines for collision sport athletes who sustain a single episode of transient cervical neuropraxia. It is generally agreed that those athletes without radiologic evidence of stenosis may RTP.18
At different disease stages
Early cervical stenosis with mild-to-moderate cord compression without edema is usually treated nonoperatively. Physical therapy along with serial neurologic examinations every 6 months ensures early myelopathic symptoms are not missed.
Neurosurgical consultation is sought when cord compression is severe or edema is seen on MRI. Even after surgery, many patients continue to complain of unsteady gait and poor balance with residual neck and/or arm pain with paresthesias, especially if a focus of abnormal signal (ie, gliosis) was appreciated in the spinal cord preoperatively.
In later stages, patients may suffer an acute injury exacerbating their chronic stenosis causing a central cord syndrome. In such cases, inpatient rehabilitation is paramount to help them restore lost function. Neurologic injury, however, may not be reversible.
Coordination of care
Physiatrists are well trained to coordinate care for both the nonathletic and athletic patient populations with cervical stenosis. Older patients with advanced disease may require physical, occupational, and psychologic therapies depending on their impairments, as well as social work services to assist with community reintegration.
Early neurosurgical consultation for athletes sustaining a single episode of cervical neuropraxia may be prudent, especially in those players found to have underlying stenosis who wish to return to full contact play (which will be subsequently discussed).
Patient & family education
A multidisciplinary team approach to counseling both older adults and young athletes with cervical stenosis should be employed. For the athlete who wishes to return to contact sports after sustaining a cervical spine injury, meeting with coaching staff, athletic trainers, and family to educate them on the risks of SCI is now standard of care. Educating family members and allied health personnel (ie, home health aides, visiting nurses) on fall risks in older adults with CSM at the time of physiatric consultation is essential.
Morbidity associated with cervical stenosis from loss of neurologic function increases with age. In those patients with SCI, functional recovery in the inpatient setting is documented utilizing serial Functional Independence Measure scores or the Spinal Cord Independence Measure, a 19-item questionnaire assessing self-care, respiration and sphincter management, and mobility.21
Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills
Participation in collision sports is implicated in the development of premature cervical spondylosis, which may increase the severity, but not necessarily the frequency, of SCI. Any player sustaining an episode of transient cervical neuropraxia should be screened with an MRI scan to rule out underlying cervical stenosis. RTP decision making should then be made on an individual basis with regard to the sport played.
Older patients presenting with neck pain, loss of cervical range of motion, and subtle changes in gait, balance, and fine motor skills should raise suspicion for cervical stenosis and be screened appropriately.
4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE
Cutting edge concepts and practice
Cervical spinal cord diffusion tensor imaging may one day be available to patients with SCI to help identify white matter tract disruption, as well as the orientation of accompanying glial scar. This technique enables detection of subtle effects of SCI injury that cannot be detected using conventional magnetic resonance techniques.22
In vivo biomechanic data has been collected in American football players using accelerometer arrays mounted on players’ helmets to measure the location and magnitude of forces necessary to produce cervical spine and head injuries.23 This data is being used to improve the safety profile of protective head gear used in collision sport athletes.
5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE
Gaps in the evidence-based knowledge
There is still no consensus on the timing of surgical intervention in older adults with asymptomatic cervical stenosis. Some surgeons advocate for earlier spinal decompression with or without fusion to prevent a catastrophic central cord syndrome, whereas other surgeons prefer to wait until the patient is clinically myelopathic.
RTP guidelines for athletes with underlying cervical stenosis remains controversial. Some experts believe that functional spinal stenosis (ie, a lack of cerebrospinal fluid around the spinal cord on MRI) represents an absolute contraindication to return to contact or collision sports; however, this criterion has yet to be fully evaluated in the literature.18 Others advocate for more liberal allowance to play with previously asymptomatic cervical stenosis.18
- Wolf BS, Khilnani M, Malis L. The sagittal diameter of the bony cervical spinal canal and its significance in cervical spondylosis. J Mt Sinai Hosp NY. 1956;23:283-292.
- Miyazaki M, Takita C, Yoshiiwa T, et al. Morphological analysis of the cervical pedicles, lateral masses, and laminae in developmental canal stenosis. Spine. 2010;35: E1381-E1385.
- Kelly JC, Groarke PJ, Butler JS, et al. The natural history and clinical syndromes of degenerative cervical spondylosis. Adv Orthop. 2012;2012:393642
- Lee MJ, Cassinelli EH, Riew KD. Prevalence of cervical spine stenosis. Anatomic study in cadavers. J Bone Joint Surg Am. 2007;89:376-380.
- Bednarik J, Kadanka Z, Dusek L, et al. Presymptomatic spondylotic cervical myelopathy: an updated predictive model Spine. 2008 Mar, 17(3): 421-431
- Edwards CC, Riew KD, Anderson PA, et al. Cervical myelopathy: current diagnostic and treatment strategies. Spine J. 2003;3:68-81.
- McCormack BM, Weinstein PR. Cervical spondylosis. An update. West J Med. 1996;165:43-51.
- Heller JG. The syndromes of degenerative cervical disease. Orthop Clin North Am. 1992;23:381-394.
- Penning L. Some aspects of plain radiography of the cervical spine in chronic myelopathy. Neurology. 1962;12:513-519.
- Torg JS, Guille JT, Jaffe S. Injuries to the cervical spine in American football players. J Bone Joint Surg Am. 2002;84:112-122.
- Denno JJ, Meadows GR. Early diagnosis of cervical spondylotic myelopathy: a useful clinical sign. Spine. 1991;16:1353-1355.
- Ebara S, Yonenobu K, Fujiwara K, et al. Myelopathy hand characterized by muscle wasting. A different type of myelopathy hand in patients with cervical spondylosis. Spine. 1988;13:785-791.
- Ono K, Ebara S, Fuji T. Myelopathy hand. New clinical signs of cervical cord damage. J Bone Joint Surg. 1987;69:215-219.
- Cote P, Cassidy JD, Yong-Hing K, et al. Apophysial joint degeneration, disc degeneration, and sagittal curve of the cervical spine. Can they be measured reliably on radiographs? Spine. 1997;22:859-864.
- Blackley HR, Plank LD, Robertson PA. Determining the sagittal dimensions of the canal of the cervical spine. The reliability of ratios of anatomical measurements. J Bone Joint Surg Br. 1999;81:110-112.
- Herzog RJ, Wiens JJ, Dillingham MF, et al. Normal cervical spine morphometry and cervical spinal stenosis in asymptomatic professional football players: plain film radiography, multiplanar radiography, and magnetic resonance imaging. Spine. 1991;16(6 Suppl):S178-S186.
- Odor JM, Watkins RG, Dillin WH, et al. Incidence of cervical spinal stenosis in professional and rookie football players. Am J Sports Med. 1990;18:507-509.
- Triantafillou KM, Lauerman W, Kalantar SB. Degenerative disease of the cervical spine and its relationship to atheletes. Clin Sports Med. 2012;31:509-520.
- Matz PG, Anderson PA, Holly LT, et al. The natural history of cervical spondylotic myelopathy. J Neurosurg Spine. 2009;11:104-111.
- Hurwitz EL, Carragee EJ, van der Velde G, et al. Treatment of neck pain: noninvasive interventions: results of the bone and joint decade 2000-2010 task force on neck pain and its associated disorders. Spine. 2008;33(4 Suppl):S123-S152.
- Catz, A., Itzkovich, M., et al. SCIM-spinal cord independence measure: a new disability scale for patients with spinal cord lesions. Spinal Cord. 1997;35:850-856.
- Bosma R, Stroman PW. Diffusion tensor imaging in the human spinal cord: development, limitations, and clinical applications. Crit Rev Biomed Eng. 2012;40:1-20.
- Broglio SP, Sosnoff JJ, Shin S, et al. Helmet impacts during high school football: a biomechanical assessment. J Athl Train. 2009;44:342-349.
Original Version of the Topic
Todd R. Lefkowitz, DO, Martin Zonenshayn, MD. Cervical stenosis. 07/11/2013.
Todd R. Lefkowitz, DO
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Ilana Etelzon, MD
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