Cervical Spinal Stenosis¶
Definition¶
Cervical spinal stenosis is narrowing of the cervical spinal canal resulting in compression of the spinal cord (cervical myelopathy) or nerve roots (radiculopathy). Because the cervical spine contains the spinal cord, cervical stenosis carries the risk of myelopathy — a potentially progressive and disabling condition.
Etiology¶
- Disc-osteophyte complex — the most common cause; combined disc bulging with posterior osteophytes
- Uncovertebral joint hypertrophy — bony spurs from the joints of Luschka; major cause of foraminal stenosis
- Facet hypertrophy — contributes to posterior and lateral narrowing
- Ligamentum flavum hypertrophy or buckling
- OPLL — ossification of the posterior longitudinal ligament; more common in East Asian populations
- Congenital stenosis — AP diameter <13 mm; predisposes to myelopathy with minimal degenerative change
Measurements¶
| Measurement | Normal | Relative Stenosis | Absolute Stenosis |
|---|---|---|---|
| AP diameter (lateral XR) | 14–23 mm | <13 mm | <10 mm |
| Torg-Pavlov ratio (canal/body) | >0.8 | <0.8 (screening only) | — |
Imaging Findings¶
MRI¶
- Sagittal T2: cord compression with loss of surrounding CSF; intramedullary T2 hyperintensity = myelopathy
- Sagittal T1: T1 hypointensity in the cord suggests chronic myelomalacia (poor prognosis)
- Axial T2: characterize location and degree of cord deformation; "bowtie" or "banana" cord shape with severe compression
- Multi-level stenosis is common — evaluate every level from C2 to C7
CT¶
- Best for evaluating osteophyte size, OPLL, and uncovertebral hypertrophy
- Essential for surgical planning (anterior vs posterior approach)
Clinical Pearl
Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction in adults over 55. The presence of T2 hyperintensity within the cord on MRI indicates myelopathy and is generally considered an indication for surgical decompression, especially if symptoms are progressive. T1 hypointensity (myelomalacia) indicates irreversible damage and a worse surgical prognosis. Patients with cord signal change should be referred to spine surgery even if symptoms are mild, as the natural history is progressive decline.
Key Points¶
- Cervical stenosis risks myelopathy because the cervical spine contains the spinal cord
- Disc-osteophyte complex is the most common cause
- Cord T2 hyperintensity = myelopathy; T1 hypointensity = myelomalacia (poor prognosis)
- AP diameter <13 mm suggests relative stenosis; <10 mm is absolute
- MRI is essential for cord assessment; CT for bony surgical planning
- Cord signal change generally warrants surgical referral
References¶
- Pavlov H, Torg JS, Robie B, Jahre C. Cervical spinal stenosis: determination with vertebral body ratio method. Radiology. 1987;164(3):771-775. https://pubmed.ncbi.nlm.nih.gov/3615879/
- Yue WM, Tan SB, Tan MH, Koh DC, Tan CT. The Torg-Pavlov ratio in cervical spondylotic myelopathy: a comparative study between patients with cervical spondylotic myelopathy and a nonspondylotic, nonmyelopathic population. Spine. 2001;26(16):1760-1764. https://pubmed.ncbi.nlm.nih.gov/11493847/
- Chen CJ, Lyu RK, Lee ST, Wong YC, Wang LJ. Intramedullary high signal intensity on T2-weighted MR images in cervical spondylotic myelopathy: prediction of prognosis with type of intensity. Radiology. 2001;221(3):789-794. https://pubmed.ncbi.nlm.nih.gov/11719680/
- Cervical canal stenosis. Radiopaedia.org. https://radiopaedia.org/articles/cervical-canal-stenosis
- Canal-to-body ratio of Torg and Pavlov. Radiopaedia.org. https://radiopaedia.org/articles/canal-to-body-ratio-of-torg-and-pavlov
- Margetis K, Donnally CJ III. Cervical Myelopathy. In: StatPearls. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK482312/
- Zileli M, Borkar SA, Sinha S, et al. Cervical Spondylotic Myelopathy: Natural Course and the Value of Diagnostic Techniques — WFNS Spine Committee Recommendations. Neurospine. 2019;16(3):386-402. https://www.e-neurospine.org/journal/view.php?number=912