Novel Instruments for Full Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion With Reverse Oblique Lateral Cage Insertion: A Case Report and Technical Note.

Background: Lumbar interbody fusion with screw fixation is a standard treatment for lumbar degenerative diseases. While full-endoscopic lumbar interbody fusion is minimally invasive, it utilizes smaller cages compared with the oblique lateral interbody fusion (OLIF) technique, which offers superior biomechanical support. To merge full-endoscopic lumbar interbody fusion minimal invasiveness with OLIF's advantages, we developed a novel instrument, the Single Beak Adjustable Cage Glider, to facilitate OLIF cage insertion via the full-endoscopic trans-Kambin triangle approach. This note and case report introduce this alternative solution.

Case Presentation: In a case of L4 to L5 spondylolisthesis, we performed fluoroscopy-guided uniportal facet-preserving trans-Kambin endoscopic fusion surgery. We initially installed percutaneous pedicle screws and rods to correct the anterolisthesis, then established the endoscopic trans-Kambin approach. After releasing the disc-endplate junction, the nerve root was mobilized and protected by the beak of the cage glider. The disc space was cleared, and a 22 × 40 × 12 mm interbody device was inserted through the cage glider under fluoroscopic guidance. The integrity of the exiting nerve root was confirmed with an endoscope.

Results: Postoperatively, the patient experienced significant improvements in both low back pain and bilateral lower limb numbness. Muscle strength in both lower limbs returned to baseline, and the patient was able to walk independently without assistive devices. Follow-up radiographs and computed tomography scans showed a well-reduced regional lordotic angle, and the axial computed tomography view confirmed adequate decompression of the spinal canal while preserving the facet joints.

Conclusions: The Single Beak Adjustable Cage Glider enables precise positioning of the OLIF cage through the Kambin triangle lumbar interbody fusion approach, avoiding nerve root injury and preserving facet joints. This technique reduces surgical trauma and maintains spine biomechanics, potentially improving patient outcomes.

Clinical Relevance: This technique potentially reduces the cage subsidence rate.