Application of anchoring of the projection point on the inner upper edge of the pedicle in minimally invasive posterior cervical foraminotomy (MI-PCF)

Purpose: To describe a new modified MI-PCF, and evaluate its feasibility/short-term efficacy. Method: Data from 21 patients with cervical spondylotic radiculopathy who were treated with the modified MI-PCF were collected. Patients’ preoperative/postoperative neck and arm pain were evaluated by the VAS, JOA and modified MacNab scores. The postoperative decompression effect was evaluated by CT and MRI. Cervical CT was performed for 3D reconstruction of the patients’ cervical spine. A cross section through the intersection of the inner and upper edges of the pedicle was used to measure the distance between the projection point on the inner upper edge of the C3-7 pedicle and the V point (a)/the midline of the spinous process (b). This distance was also measured in human cadavers(c)/(d). Result: The operation was successful in all patients. The mean operative duration was 70.1± 20.0 min, and the mean number of fluoroscopies was 4.0± 0.9 times. The VAS, JOA and modified MacNab scores were all significantly improved. The values of a, b, c, and d for C3-7 were 1.43 ± 0.07 ~ 4.98 ± 0.22 mm, 14.00 ± 0.29 ~ 16.35 ± 0.45 mm, 1.47± 0.08 ~ 5.08 ± 0.25 mm, and 14.04 ± 0.32 ~ 16.36± 0.43 mm, respectively. Conclusion: The number of fluoroscopies and the operative duration were reduced by the anchoring of the projection point on the inner upper edge of the pedicle. Overall this study describes a new method for positioning and verification of the V point in MI-PCF.