O-arm navigation-guided uni-portal non-coaxial spinal endoscopic surgery for the precise treatment of far-out syndrome-a case report and literature review.

Far-out Syndrome is a rare condition involving extracanal compression of the L5 nerve root at the far-lateral region where it passes between the L5 transverse process and the sacral ala. The limited availability of advanced imaging modalities constrains the detection rate of far-out Syndrome. Correspondingly, a standardized surgical approach has not yet been fully established within the medical community. In this case we firstly introduce the combined use of O-arm navigation and uni-portal non-coaxial spinal endoscopic surgery to manage far-out Syndrome. A 67-year-old male presented to us with chief has complaint of left lower limb radiculopathy and numbness and paresthesia for 1 year. The patient underwent nerve root block and endoscopic decompression right after the onset of these symptoms with little improvement. His preoperative computed tomography scan revealed compression of left L5 nerve root in the extraforaminal region and confirm the diagnosis of far-out Syndrome. Uni-portal non-coaxial spinal endoscopic surgery decompression via paraspinal approach was performed for his under O-arm navigation. The immediate relief of symptoms post-surgery and the absence of significant recurrence during the 6-month follow-up period suggest that this surgical approach is a safe and reliable treatment option for far-out Syndrome.