Interlaminar Endoscopic Lumbar Discectomy: A Narrative Review

Surgical techniques. (A) Skin incision. The skin incision (yellow line) is overlaid on the spinal myelogram to better understand the surgical trajectory. Usually, transversing nerve roots passing below the lateral margin of the interlaminar window and straight trajectories are associated with a risk of nerve root injury. (B) Preoperative magnetic resonance image and surgical trajectory. The surgical trajectory was oriented obliquely lateral, and the dilator, working tube, and endoscope were medially inclined for the trajectory until opening of the ligamentum flavum and identification of the nerve root. (C) Opening of ligamentum flavum. The outer layer of the ligamentum flavum is incised with scissors (thick arrow), and the inner layer is carefully opened with scissors (double arrow). (D) Rotation of the working tube and retraction of the nerve root. After dissecting the lateral border of the nerve root, the dissector was placed under the nerve root, and the working tube was gently rotated. The dissector was used to put the nerve root away from the blade of the working tube while rotating the working tube. (E, F) Sealing of the annular defect. After removal of the ruptured disc and loose fragments, the defect at the annulus (arrow) is narrowed by coagulating the annulus while pushing the annulus to the side of the defect. (G) Postoperative magnetic resonance imaging. Postoperative T2-weighted axial magnetic resonance image showed a defect in the ligamentum flavum and disappearance of the ruptured disc. The yellow arrow indicates the surgical trajectory, and the opening in the ligamentum flavum was shown with a high signal at the end of the yellow arrow.