Minimally Invasive Full-endoscopic Posterior Cervical Foraminotomy and Discectomy: Introducing a Simple and Useful Localization Technique of the "V" Point.

Objective: Conventional localization technique of V point for full-endoscopic posterior cervical foraminotomy and discectomy (FPCD) required repeated fluoroscopies, especially in patients with short and thick necks. To address this issue, the present study aimed to introduce a new localization technique of V point, and further evaluate its efficacy.

Methods: A K-wire was inserted and fixed at the pedicle eye under A/P fluoroscopy, then a working channel was established quickly along with it. Thirty-four patients who underwent minimally invasive FPCD assisted by the new technique were included in this study. The clinical and radiological data were collected and analyzed, including radiation dose, operative time, positioning time, visual analog scale (VAS) for neck and arm pain, neck disability index (NDI) scores, Cobb angle of operative level and range of motion of the cervical spine.

Results: All operations were performed successfully, and no iatrogenic nerve or vascular injury occurred. None of the patients needed to be transferred to open surgery or revision surgery. The mean radiation dose was found to be1.68 ± 0.36 mSv. The mean positioning time observed was 10.68 ± 5.42 min and the average operation time was 81.18 ± 10.87 min. The operation time significantly declined as the number of patients increased. A significant difference in operation time between the first (96.22 ± 10.36 min) and last quartile (75.00 ± 3.84 min) of cases was observed (t = 4.82, P < 0.001). The VAS scores for neck and arm pain, and NDI scores were significantly improved after surgery (P <0.0001, P <0.0001, P <0.0001). Based on MacNab criteria, the excellent plus good rate was 91.17%. The Cobb angle of operative level and range of motion of the cervical spine were significantly improved postoperatively (t = 2.846, P  = 0.015; t = 2.232, P  = 0.026).

Conclusion: The new image-assisted V point localization technique is simple and useful with little radiation exposure and short positioning time. FPCD assisted by the new technique could be a safe and effective alternative on properly selected patients.