O-Arm Navigation-Guided Unilateral Biportal Endoscopic Decompression of Far-Out Syndrome.

The main aim of this video article is to demonstrate the combined use of O-arm navigation and unilateral biportal endoscopy (UBE) to manage far-out syndrome (FOS). In FOS there is entrapment and compression of the fifth lumbar nerve beyond the foramen and between L5 transverse process and the sacral ala at the lumbosacral junction. Conventional microscopic decompression using a paraspinal approach had been the gold standard for its management. However, the surgery is technically challenging due to the deep location of the pathology and intricate anatomy of extraforaminal space. There have been some published reports of unsatisfactory outcomes with microscopic decompression for FOS. We decided to integrate navigation with UBE to increase precision for the management of FOS. A 70-year-old female presented to us with chief complaint of left lower limb radiculopathy since 1 year. She also complained of numbness and paresthesias in her left leg and foot. She was unable to walk for more than 10 minutes due to pain. Her magnetic resonance imaging scan revealed compression of left L5 nerve root in the extraforaminal region. UBE decompression via paraspinal approach was performed for her under O-arm navigation. She experienced immediate relief of her symptoms in the postoperative period. O-arm-navigation-guided UBE is an effective and safer alternative to microsurgical decompression for the management of FOS. This video demonstrates the step-by-step implementation of O-arm navigation with endoscopy and its precise execution.