Comparative Evaluation of Posterior Percutaneous Endoscopic Cervical Discectomy Using 3.7mm Endoscopic and 6.9mm Endoscopic for Cervical Disc Herniation: a retrospective comparative cohort study.

Abstract

Background. Posterior percutaneous endoscopic cervical discectomy (p-PECD) is an effective strategy for cervical diseases which working cannula ranges from 3.7 mm to 6.9 mm. However, no studies were performed to compare the clinical outcomes of endoscopes with different diameters in cervical disc herniation (CDH) patients. The purpose of this study was to compare the clinical outcomes of unilateral CDH patients treated with p-PECD applying the 3.7mm endoscopic with those treated with the 6.9mm endoscopic. Methods. From January 2016 to June 2018, totally 28 consecutive patients presented with single-level CDH who received p-PECD using the 3.7mm endoscopic or the 6.9mm endoscopic were enrolled. The indications for this study were as follows: (1) Unilateral cervical spondylotic radiculopathy with pain irradiated to upper extremity, (2) MRI and CT scan show that foraminal CDH located lateral to the edge of spinal cord, from C4–C5 to C7–T1, (3) Unilateral symptoms caused by foraminal stenosis, (4) Failure after conservative treatment for at least 6 weeks or neurological symptoms aggravated. Patients were evaluated neurologically pre- and postoperatively. The clinical outcomes, including the operation time, the hospitalization, the visual analogue scale (VAS) and the modified MacNab criteria, were evaluated. Cervical fluoroscopy, CT, and MRI were performed during follow up.Results. The mean surgical duration of the 3.7mm endoscopic was 76.5 minutes compared with 61.5 minutes for 6.9mm endoscopic (P<0.05). Moreover, there was significant difference with regard to average identification time of “V” point (18.608±3.7607min vs. 11.256±2.7161min, p＜0.001) and mean removal time of overlying tissue (16.650±4.1730 min vs. 12.712±3.3079 min, p＜0.05) between 3.7mm endoscopic and 6.9mm endoscopic. The VAS and MacNab scores postoperatively of the two endoscopies were significantly improved compared with that before operation (p＜0.05).Conclusion. Both 3.7mm endoscopic and 6.9mm endoscopic are effective methods for CDH in selected patients, and there is no significant difference in clinical outcomes. 6.9mm endoscopic is superior to 3.7mm endoscopic in the efficiency of “V” point identification, overlying soft tissue removal and spinal cord injury prevention. Furthermore, 6.9mm endoscopic is inferior to 3.7mm endoscopic in anterior decompression of the intervertebral foramen.