Computed tomographic evaluation of C5 root exit foramen in patients with cervical spondylotic myelopathy

BACKGROUND: Narrowing of the intervertebral foramen for C5 root and a larger superior articular process in myelopathic patients with postlaminoplasty motor dominant C5 radiculopathy has been reported. We investigated whether the C4-5 foraminal dimensions and surface area in patients with cervical spondylotic myelopathy are universally smaller than the intervertebral foramina at other cervical levels. METHODS: The study population consisted of 44 consecutive patients (sex: 24 males and 20 females), averaging 55.7 years of age (range 42-84) years who presented with clinical features suggestive of cervical spondylotic myelopathy. Using computed tomography (CT) imaging, we prospectively compared height, transverse diameter, and surface area of the C4-5 foramen to those of C3-4, C5-6 and C6-7 foramina of the same side in the whole study population as well as in male and female patients. RESULTS: In the whole study population at C4-5 intervertebral foramen the mean foraminal height was 8.37 ± 1.3 mm on the right and 8.85 ± 1.16 mm on the left; and the mean foraminal transverse diameter on the right was 4.97 ± 1.35 mm and 5.14 ± 1.16 mm on the left. No statistically significant difference was found between the measurements in the whole study population at various levels, between or within male and female patient groups. CONCLUSION: C4-5 intervertebral foramen is not uniformly smaller in patients with cervical spondylotic myelopathy.