Cervical Disc Level Most Commonly Associated with Spur Formation
The C5-6 level is most commonly associated with spur formation in the cervical spine, followed by C6-7 and C4-5 levels. 1
Anatomical Distribution of Cervical Spur Formation
Cervical spur formation follows a distinct pattern of distribution across the cervical spine:
- C5-6 level: Most common site (28% of cases) 2
- C6-7 level: Second most common site
- C4-5 level: Third most common site
- C3-4 level: Less common site for spur formation, but has higher rates of heterotopic ossification after surgical intervention 3
Pathophysiology of Cervical Spur Formation
Spur formation in the cervical spine typically occurs due to:
- Degenerative disc disease progression
- Increased mechanical stress at mobile segments
- Natural aging process affecting the intervertebral discs
- Abnormal biomechanical forces leading to osteophyte formation
Clinical Implications
The location of cervical spurs has significant clinical implications:
- C5-6 level spurs: Often associated with C6 radiculopathy (weakness of wrist extension, diminished brachioradialis reflex)
- C6-7 level spurs: Typically cause C7 radiculopathy (weakness of triceps, diminished triceps reflex)
- C4-5 level spurs: May lead to C5 radiculopathy (weakness of deltoid and biceps)
Diagnostic Evaluation
When evaluating for cervical spur formation:
- CT scan: Superior for identifying spur thickness and extent (94-100% sensitivity) 4
- Plain radiographs: Less reliable (49-82% sensitivity) but useful as initial screening 4
- MRI: Best for assessing cord compression and signal changes, but less sensitive for detecting bony spurs 4
Management Considerations
The approach to managing cervical spurs depends on their location:
- Anterior approach: Preferred for C5-6 and adjacent levels due to better surgical access
- Posterior approach: May be considered for foraminal spurs causing unilateral radiculopathy 5
Surgical Outcomes
Surgical outcomes for cervical spur management vary by level:
- C5-6 level: Highest rate of adjacent segment disease (ASD) after fusion (28%) 2
- C3-4 level: Higher rates of heterotopic ossification (90.9% vs 58.44% at other levels) 3
Pitfalls and Caveats
Important considerations when managing cervical spurs:
- Preexisting radiological signs of degeneration increase risk of adjacent segment disease (74% of cases) 2
- Poor sagittal alignment after primary surgery increases risk of adjacent segment disease (90% of cases) 2
- Multiple level involvement is common and requires careful preoperative planning 6
Understanding the predilection for spur formation at C5-6 helps guide clinical assessment and surgical planning for patients with cervical spondylosis.