A total of 30 patients with L5-S1 LDH in our department were enrolled. Full-endoscopic visualized foraminoplasty and discectomy were performed under general anesthesia in the First Affiliated Hospital of Henan University of Traditional Chinese Medicine from March 2018–2019.
Inclusion criteria: Single-level lumbar disc herniation at L5-S1, verified by magnetic resonance imaging (MRI) and computed tomography (CT); unilateral radiating leg pain with or without positive Lasegue sign; clinical symptoms and signs in accordance with imaging changes; failure of standard conservative treatment conducted for at least 12 weeks. Exclusion criteria: Vertebral infection, vertebral tumor, spinal canal stenosis, lumbar spondylolisthesis, and a history of surgery at the same level.
The operation time, the visual analog scale of lower limbs (VAS-L), visual analog scale of back (VAS-B), and Oswestry disability index (ODI)  before surgery, 1 day, and 1 week after surgery were used for clinical evaluation.
All data were analyzed by SPSS21.0 statistical software, and relevant graphs were constructed using Microsoft Excel. The measurement data were expressed as mean ± standard deviation and the preoperative and postoperative data were analyzed by paired sample t-test, while the enumeration data were compared using the rank-sum test or X2 test. P-value <0.05 indicates statistical significance.
We have studied and applied the operation technique of Professor Yang from the Union Hospital Affiliated to the Huazhong University of Science and Technology . The preoperative images (Figure 1) were firstly evaluated, the operation was performed under general anesthesia, and the posterior interlaminar space approach was adopted. The patient was in the lateral position, with limb of the affected site on the top and flexion of bilateral knees and hips to fully open the interlaminar space. The anteroposterior and lateral X-ray films of the corresponding segments were obtained by C-arm fluoroscopy to accurately locate the intervertebral pore. The syringe needle was inserted into the skin to locate the point where the needle entered the L5-S1 intervertebral space vertically from the back of the lumbar . The anteroposterior X-ray film indicated that the positioning needle was in the middle of the affected side of the intervertebral space, while the lateral X-ray film indicated that the positioning needle was at the level of the posterosuperior margin of S1. The puncture target and direction were determined according to the X-ray films to ensure the accuracy of the surgery site.
After positioning, a longitudinal incision of about 1 cm was made along the direction of the spine with the registration point as the center. After the pencil-shaped puncture rod was inserted into the interlaminar space, the working cannula and the operating endoscope were inserted slowly along the puncture rod into the interlaminar space. All subsequent operation procedures were performed under the premise of continuous irrigation and endoscopic visualization. The inferior zygapophysis of the L5 vertebral body and the lower margin of the lamina were found under the direct vision of the endoscope. If the interlaminar space was small, a part of zygapophysis at foramen intervertebral could be enlarged by grinding with an abrasion drill under the endoscope (Figure 2). Then, the blue forceps removed a part of the ligamentum flavum into the spinal canal, lamina rongeur enlarged the crevasse of the ligamentum flavum to fully expose the tissues in the spinal canal, the bipolar radiofrequency scalpel separated the tissues in the spinal canal to fully expose the nerve root, dural sac, and annulus fibrosus, the sleeve was rotated into the spinal canal to protect the nerve root, annulus fibrosus fenestration was performed on the outer margin of the nerve root, the working sleeve was guided to the annulus fibrosus opening, and full endoscopic resection of the nucleus pulposus was performed to ensure complete decompression of the nerve root. During this process, the nerve root was clearly identified, and no free intervertebral disc tissue or active bleeding was observed before the end of the operation. (Figure 3) Finally, bipolar radiofrequency scalpel was adopted to control the bleeding, the external annulus plasty of the intervertebral disc was performed, and the incision was closed without additional drainage at the end.