The strategy and results of percutaneous endoscopic surgery for cervical disc herniation

Objective To evaluate the strategy and clinical effects of percutaneous endoscopic surgery for cervical disc herniation. Methods Fifty-one patients with cervical disc herniation were treated with percutaneous endoscopic surgery from June 2015 to March 2017, including 32 men and 19 women, with an average age of 52.2 years (range, 28-66 years). Radicular symptoms were present in all patients, while 23 patients had mild myelopathy (Nurick Grade: 0-3) and 3 patients of multilevel stenosis had severe myelopathy (Nurick Grade: 4-5). According to axial image of preoperative magnetic resonance imaging (MRI), 31 patients had lateral herniation that was located lateral to the edge of spinal cord, 20 patients had central herniation that was located within the lateral edge of spinal cord. Among them, 48 patients had soft herniation and 3 patients had ossified lateral herniation combined with foraminal stenosis. All surgery was carried out under general anesthesia, while posterior and anterior percutaneous endoscopic surgeries were performed for lateral herniation and central herniation respectively. Posterior endoscopic surgery was performed with keyhole fenestration at V point (the junction of lateral edge of lamina space and inner edge of facet). Lateral edge of thecal sac and nerve root were exposed and decompressed, soft herniation was explored and removed. Anterior endoscopic surgery was performed through puncture and 4mm tube between the visceral sheath and vascular sheath. The tube was inserted through disc to the base of herniation under fluoroscopy. The herniation was removed until the dura sac was exposed and relaxed. One stage open-door laminoplasty was performed for 3 patients with severe multiple segmental stenosis and huge central herniation. The operative time and blood loss were recorded, and patients were followed-up (range, 6-18 months, average 12.1 months) to evaluate the clinical efficacy. Results The mean operative time of posterior endoscopic surgery was 90 min (range, 45-150 min). The nerve root was not well exposed, and the fenestration was too lateral in 1 patient, with partial relieve of symptoms; and simple nerve root decompression was performed for 3 patients of ossified herniation combined with foraminal stenosis. Herniated or sequestered nucleus pulposus was removed for 27 patients, one of them had transient paralysis ipsilateral limb and 2 of them had linkage of cerebrospinal fluid. The Visual Analogue Score (VAS) score improved form preoperative 8.9±1.6 to 0.5±0.4, and the Oswestry Disability Index (ODI) score improved form 32.8±4.2 to 2.3±1.9 at final follow-up. For anterior percutaneous endoscopic surgery, the mean operative time was 80 min (range, 45–120 min). Herniated or free nucleus was successfully removed for all patients. The thecal sac was lacerated due to unclear exposure in 1 case. The VAS score improved form preoperative 6.9±2.3 to 0.9±0.8, and the ODI score improved form 40.1±8.6 to 5.6±3.0 at final follow-up, with improvement of myelopathy at least one Nurick Grade. During follow-up, the alignment of cervical spine was well preserved without kyphosis for two groups, while the height of intervertebral space decreased with 0.4±0.3 mm and 0.9±0.6 mm in posterior and anterior surgery respectively. Conclusion Percutaneous endoscopic surgery provides minimally invasive alternatives for some cervical disc herniation with predominant radicular pain. Posterior endoscopic surgery is suitable for lateral herniation, and anterior endoscopic discectomy is suitable for some central soft herniation without obvious collapse and instability. However, the long-term results of disc space collapsed after anterior approach remains unclear. Key words: Cervical vertebrae; Intervertebral disc displacement; Endoscopy; Surgical procedures, minimally invasive