Modified Full-Endoscopic Interlaminar Discectomy via an Inferior Endplate Approach for Lumbar Disc Herniation: Retrospective 3-Year Results from 321 Patients

Abstract

Background: Percutaneous endoscopic interlaminar discectomy (PEID) is a widely used minimally invasive procedure that shows satisfying outcomes for the treatment of L5-S1 and even L4-5 disc herniation. PEID can be divided into direct and indirect approaches according to the established method of the working channel. The direct approach mainly uses the puncture needle directly through the intervertebral space into the intervertebral disc under indirect vision and insertion of the guidewire into the puncture needle to guide the dilator and into the working channel to retract the ligamentum flavum, dural sac, and nerve roots. This approach requires a skilled puncture technique, given the high risk of damage to the nerve roots and dural sac. Therefore, we improved this interlaminar access procedure, placing the puncture target at the inferior endplate and performing preoperative epidurography to expose the spinal nerve roots and dural sac after the puncture needle was passed through the ligamentum flavum. We then positioned the puncture needle at the posterior edge of the superior centrum. Finally, we inserted the working sleeve for the operation. This approach is convenient and effectively reduces the learning curve and intraoperative complications. Here we introduce the procedure and report the safety and efficacy of full-endoscopic interlaminar discectomy via an inferior endplate approach for the treatment of lumbar disc herniation.

Methods: We performed full-endoscopic interlaminar discectomy via the inferior endplate approach in 321 patients who met our inclusion criteria between May 2014 and May 2017. All operations were completed under local anesthesia. Under fluoroscopic guidance, we performed epidurography to expose the spinal nerve roots and dural sac. The working sleeve and endoscope were then introduced into the inferior endplate of the superior centrum. Herniated disc material was removed using forceps and a laser under clear endoscopic visualization. We retrospectively evaluated the 321 patients with more than 30 months (range, 12-48 months) of follow-up. The therapeutic effects were assessed using scores of the visual analog scale (VAS), Oswestry disability index (ODI), Macnab standard, and infrared thermal imaging.

Results: The mean VAS score for radicular pain improved from 6.3 ± 1.01 preoperatively to 1.01 ± 0.35 at the final follow-up (P < 0.01). The mean ODI score improved from 85.5 ± 12 preoperatively to 12.4 ± 3.7 at the final follow-up (P < 0.01). According to the MacNab standard, the excellent and good outcome scores were 96.5%. The infrared thermal imaging scores indicated significantly improved skin temperature of both lower extremities at 1 week after surgery compared with the preoperation temperature (P < 0.01).

Conclusions: The inferior endplate approach for percutaneous endoscopic interlaminar discectomy provides a safe and effective alternative for the treatment of lumbar disc herniation.

Keywords: Full-endoscopic interlaminar discectomy; Inferior endplate approach; Lumbar disc herniation; Pain.