Anatomical Importance Between Neural Structure and Bony Landmark: Clinical Importance for Posterior Endoscopic Cervical Foraminotomy

OBJECTIVE: Posterior endoscopic cervical foraminotomy (PECF) is a well-established, minimally invasive surgery for cervical radiculopathy, but have the more chances of neural structure damage due to the limited visibility and steeper learning curve. So, the anatomical understanding of the nerve associated with the bony structure will be an essential surgical guideline. METHODS: We measured the distance between the bilateral dura lateral edge and bilateral V-point on axial cuts of cervical magnetic resonance imaging and 3-dimensional spine computed tomography imaging, respectively, from 80 patients. We then calculate the distance and position between the dura lateral edge and the V-point as surgically critical width (SCW). Transverse interdural distance (TIDW), transverse inter-V-point distance, and anatomical facet joint width were measured. RESULTS: The mean TIDW decreased as the levels down in the 40s–60s but increased at the C4–5, C5–6, and C6–7 levels in the 70s. Statistically significant difference was shown at the C6–7 level between the 40s and the 70s. The mean anatomical inter-V-point distance markedly decreased at C5–6 and continued till the C7–Tl level at all age groups. Moreover, a statistically significant difference was shown at the C3–4 and C4–5 level between the 40s and the 70s. The mean negative values of SCW increased from the 40s to 70s at the C5–6 and C6–7 levels (C5–6: -0.60 ± 1.10 mm to -1.63 ± 1.56 mm; C6–7: -0.90 ± 0.74 mm to -2.18 ± 1.25 mm). There were statistically significant differences between the 2 aged groups at the C3–4, C4–5, C5–6, and C6–7 levels. CONCLUSION: A prediction of the correlated position between the lateral dura edge and the V-point is essential for the PECF not to injure the neural structure. In the case of a performing the PECF at the C5–6 and C6–7 level in the old-aged patient, it should be considered the laterally moved dura edge, and more extended bony remove is needed for less neural structure damage.