The Effect of Cervical Lordosis on Cervical Disc Degeneration in Patients with a High T1 Slope

ABSTRACT

STUDY DESIGN: Retrospective evaluation. OBJECTIVES: To analyze the effect of cervical lordosis on cervical disc degeneration in patients with a high T1 slope. SUMMARY OF LITERATURE REVIEW The T1 slope is known to be a parameter that may be very useful in evaluating sagittal balance. We previously reported that a low T1 slope was a potential risk factor for cervical spondylosis, especially in the C6–7 cervical segment. However, no study has analyzed the effect of cervical lordosis in patients with a high T1 slope (>25) on cervical disc degeneration. MATERIALS AND METHODS: Seventy-seven patients with a high T1 slope who underwent cervical spine MRI in our orthopedic clinic were enrolled. Patients were divided into 2 groups according to cervical compensation. The radiologic parameters obtained from radiography and cervical spine MRI were compared between the uncompensated group (cervical lordosis <25) and the compensated group (cervical lordosis ≥25). RESULTS: In the uncompensated group, the average degeneration grade of each segment was 2.72 (±0.70) in C2–3, 3.00 (±0.76) in C3–4, 3.02 (±0.91) in C4–5, 3.37 (±0.95) in C5–6, and 2.95 (±0.98) in C6–7. The average degeneration grade of each segment in the compensated group was 2.38 (±0.78) in C2–3, 2.38 (±0.60) in C3–4, 2.62 (±0.60) in C4–5, 2.82 (±0.72) in C5–6, and 2.41 (±0.74) in C6–7. The degeneration grade was significantly higher in the uncompensated group than in the compensated group for all cervical segments. The risk of high-grade degeneration of C3–4 was significantly higher in the uncompensated group (odds ratio = 6.268; 95% CI, 2.232–17.601; p<.001). CONCLUSIONS: Patients with a high T1 slope without compensation of cervical lordosis had a higher grade of degeneration in all cervical segments.