Full Endoscopic Interlaminar Contralateral Lumbar Foraminotomy for Recurrent L5-S1 Foraminal-extraforaminal Stenosis: A Case Report with a Technical Note

After endoscopic lumbar foraminotomy, decreased disc height commonly causes foraminal restenosis and accompanying lateral recess stenosis. Interlaminar contralateral endoscopic lumbar foraminotomy can be used to treat multiple recurrent lesions instead of fusion surgery. Dorsal foraminal-extraforaminal decompression is challenging because of severe perineural adhesions. Therefore, neural decompression should be focused on the ventral foraminal expansion along the virgin dissection plane between the exiting nerve root and ventral foraminal pathologies. The prominent bony spur and herniated disc were removed using an endoscopic drill and forceps. As the foramen was enlarged, the endoscope was introduced deeper through the caudal-ventral foramen space to explore the extraforaminal and far-out lesions. Postoperatively, neurological deficits of L5 radiculopathy and radiating leg pain improved. The expanded foraminal-extraforaminal space was well maintained without progression of lateral wedging on the one-year follow-up images. We successfully treated recurrent foraminal-extraforaminal stenosis and combined lateral recess stenosis using the full endoscopic interlaminar contralateral approach at the L5-S1 level. This technique may be an alternative surgical method to treat the recurrent foraminal-extraforaminal stenosis in the collapse of the L5-S1 neuroforamen. However, this technique should be considered in highly selected patients unsuitable for fusion operations.