Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive spinal technique that has several advantages over open discectomy, including less paravertebral muscle injury, preservation of bony structure, and rapid recovery. PELD has gained popularity for removal of herniated disc (HD) material over the past few years since Kambin introduced the percutaneous posterolateral approach in 1983. Remarkable evolution of endoscopic techniques and instrumentation leads to successful outcomes comparable to conventional open surgery. PELD has been applied to various types of disc herniation and the indication has been expanded. I propose various strategies for PELD according to various types of disc herniation.
Herniated disc (HD) with migration was classified into four zones: low-grade up/down and high-grade up/down based on the extent and direction of migration. High-grade up HDs can be removed with the outside or outside-in techniques from L1-2 to L4-5. High-grade down HDs can be removed using the outside technique with additional foraminoplasty. Low-grade up/down HDs with disc space continuity can be removed using the inside-out technique. Without continuity, the outside technique or foraminoplasty may be needed. Meanwhile, at the L5-S1 level, interlaminar PELD is used to treat high-grade up/down HD with migration.
Foraminal/extraforaminal disc herniation
The approach angle is steeper than conventional posterolateral approach. The entry point is about 7–10 cm depending on disc location. The approach angle is about 30–50°. In case of foraminal/extraforaminal disc herniation, invading the axilla of the exiting root, the area available for cannula insertion increases due to the lateral displacement of the corresponding nerve root. It is concerned about postoperative dysesthesia with manipulation of exiting nerve root. We should use a radiofrequency probe, laser, and working cannula carefully.
Proper surgical indications and good working cannula position are important for successful PELD. PELD techniques should be specifically modified to remove the disc fragments in various types of HD.
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