Feasibility study of ultrasound-guided percutaneous laser discectomy for cervical radicular pain

Percutaneous laser discectomy is one common and effective treatment for cervical radicular pain. Currently, the surgery is performed with blind cannulation technique, mainly relies on the experience of surgeon. However, it still remains unsafe and difficult to reach the target. As an alternative, ultrasound-guided cannulation provides visualization of important structures, thus increasing the precision and safety. The primary goal of this study is to report the detail of the ultrasound-guided technique in the percutaneous laser cervical discectomy. The secondary purpose is to evaluate the feasibility of the novel therapy. This is a single center, feasibility study conducted in one teaching hospital. Thirteen intervertebral discs in 9 patients presented with cervical radicular pain. Accuracy of the cannulation with ultrasonic guidance was confirmed by the anterior-posterior and lateral view of fluoroscopy. We compared the pain severity pre- and post-treatment with Visual Analogue Score (VAS), and functional improvement was assessed with the modified Macnab Criteria and Neck Disability Index (NDI) respectively. Ultrasonic short-axis was used to scan the cervical nerve root, and its transition was used to identify the distinct intervertebral space. Following the recognition of targeted cervical level, the ultrasound probe was moved medially for the visualization of the surface of the cervical vertebrae. In plane cannulation was then applied to avoid the injury of the vessels. The location of cannula was confirmed by the fluoroscopic imaging. Low-power laser was set for the cervical disc ablation in this cohort. The majority of the surgical sites maintained in the C5/6 level (38%), and 31% for the C6/7 level respectively. Despite the distinct cervical level, the tip of needle was properly placed near by the targeted intervertebral disc in all participants, which was confirmed by the imaging of fluoroscopy. We did not observe any obvious complications during the procedure. The mean VAS decreased from 7.6 ± 1.1 to 2.3 ± 2.7 one month after discharge, and 2.1 ± 2.6 at the last follow-up (median duration of nine months). All patients reported significant improvement of NDI up to last follow-up (p = 0.011). Meanwhile, the good to excellent rate was reported in 8 of 9 patients (89%) according to the modified Macnab Criteria. The finding of this feasibility assessment indicates the ultrasound-based cannulation technique is capable of guiding the cannulation for the percutaneous laser discectomy. It may facilitate identifying the corresponding site of cervical intervertebral disc and prevent the damage of vessel.