Interlaminar Approach in the Lumbar Spine

Herein, we describe the surgical techniques of endoscopic interlaminar approach in the lumbar spine through a video presentation of cases involving 3 patients. In every procedure using the interlaminar approach, the lower margin of the lamina should be first identified and used as a surgical landmark. Laminectomy with drilling begins from the lower margin of the lamina and continues upward along the ligamentum flavum. The laminectomy ends when the drill meets the midline cleft of the ligamentum flavum. Once the midline cleft has been detected, an additional bony work-up is performed to detach the lateral and lower margins of the ligamentum flavum. Then, the ligamentum flavum is removed and the thecal sac is exposed. Full exposure of the lateral margin of the thecal sac and ipsilateral traversing root is required. For cases that require contralateral decompression, an additional contralateral bony work-up and decompression of the contralateral traversing root are performed. Decompression of the contralateral exiting root can also be performed with the advantage of a wide endoscopic view angle. Retraction of the thecal sac and traversing root exposes the surface of the disc, and discectomy can be performed. Before the termination of surgery, surgeons should always confirm sufficient decompression of the nerve roots and hemostasis.