Does the C3/4 disc play a role in cervical spondylosis with dizziness? A retrospective study

To investigate the effect of C3/4 disc degeneration on cervical spondylosis with dizziness (CSD) and to assess the curative effect of anterior cervical decompression and fusion (ACDF) in patients with CSD.

Four hundred nineteen patients who underwent ACDF for treatment of myelopathy or radiculopathy were divided into dizziness and non-dizziness group. The visual analog scale (VAS) score and Japanese Orthopaedic Association (JOA) score were used to determine the intensity of dizziness and neurological symptoms, respectively. Cervical disc degeneration was evaluated using Miyazaki's classification system. Some parameters were measured using cervical radiographs. The surgical effects on CSD were compared between surgery with and without C3/4 level. Multivariate logistic regression analysis was used to determine the risk factors for CSD.

The pre-operative incidence of CSD was 33.9%. Women were more likely to develop dizziness than men (p < 0.05), CSD was significantly associated with C3/4 disc degeneration (69.7%, p < 0.001), and smokers were more subject to dizziness (p < 0.05). Regression analysis showed that female (OR = 1.611, p = 0.031), smoking (OR = 1.719, p = 0.032), Miyazaki grade of C3/4 ≥ IV (OR = 2.648, p < 0.001), and instability on C3/4 (OR = 1.672, p = 0.024) were risk factors for CSD. Treatment of CSD by ACDF involving C3/4 was more effective than not involving C3/4 (efficacy rate, 73.2% vs 51.7%, p < 0.05).

The CSD is a common clinical manifestation in elderly patients, especially patients with cervical spondylosis at the C3/4 level. Female, smoking, instability on C3/4, and C3/4 Miyazaki grade ≥ IV could be considered significant risk factors for CSD. CSD is more likely to be alleviated by ACDF involving C3/4.