Reimagining UBE: Midline Biportal Endoscopic Approach with "Under the Cave" Decompression Technique for Lumbar Canal Stenosis-A Technical Note and Clinical Pearls.

The purpose of this study was to describe the technique for midline biportal endoscopic decompression (MBED) for lumbar canal stenosis by a new "under the cave" decompression technique: a paradigm shift in biportal endoscopic decompression. Laminectomy with/without fusion and facet-preserving microforaminotomy has been performed as conventional surgical treatments for lumbar canal stenosis (LCS). Recently, endoscopic spinal surgery has been introduced as a minimally invasive therapeutic modality of LCS by several authors. Here, we describe the surgical steps and technical pearls of MBED with "under the cave" decompression technique in LCS, successfully treated with a modification to the novel unilateral biportal endoscopic (UBE) spine surgery technique, that is, by using a more midline approach using primary two portals. The authors included patients who presented with chronic onset of back pain and neurogenic claudication symptoms. They were diagnosed with LCS from magnetic resonance imaging and computed tomography preoperatively. The surgery was performed via unilateral approach to achieve bilateral compression without additional skin incisions by "under the cave" decompression technique and primary two portals. This technique ensures complete decompression of the spinal canal as compared to the microscopic, tubular, and traditional UBE. Midline modification of the conventional BED done through the "under the cave" technique permits clear visualization of ipsilateral and contralateral sublaminar and foraminal areas. Owing to this enhanced exploratory capability it gives us a good outcome in terms of complete decompression of the ipsilateral and contralateral exiting roots while avoiding fusion in the elderly. The authors suggest that the new MBED, which is minimally invasive, is a good alternative treatment option for degenerative LCS.