1. 2025;28;E525-E533Full Endoscopic Decompression Surgery for Far-Out Syndrome Via Pseudoarthrosis Formed by L5 Transverse Process and Sacral Ala: A Preliminary Outcome
   Retrospective Analysis
   Hao Hu, MS, Fu-Kuan Zhu, MS, Lei Shi, MD, Rui Deng, MD, Xi-Zi Miao, MS, Ya-Feng Wen, MD, Zhen-Yong Ke, MD, Xiao-Min Sheng, MD, Lei Chu, MD, and Zhong-Liang Deng, MD, PhD.

BACKGROUND: Far-out syndrome (FOS) refers to the compression of the L5 nerve root in the extraforaminal region by a pseudoarthrosis formed between the L5 transverse process and the sacral ala. If conservative treatment for this condition fails, surgical intervention should be considered. 

OBJECTIVES: This study aims to introduce a minimally invasive endoscopic technique for treating FOS via the pseudoarthrosis approach.

STUDY DESIGN: A technical note and preliminary outcome.

METHODS: We retrospectively analyzed the medical history, physical examination, auxiliary examinations, and imaging data as well as the visual analog scale (VAS), Oswestry Disability Index (ODI), and Macnab scores of 5 FOS patients treated with minimally invasive endoscopic surgery at our hospital from April 2024 to July 2024. The implementation process of this surgical technique is illustrated through typical cases.

RESULTS: We performed decompression surgery via the L5 transverse process-sacral ala pseudoarthrosis approach using full endoscopy, which successfully relieved the clinical symptoms in the 5 patients. The patients’ postoperative VAS scores were significantly lower than the preoperative scores (P = 0.041). Similarly, the postoperative ODI scores were markedly decreased (P = 0.043), and the last follow-up showed a 100% excellent rate (Macnab score). Imaging examination indicated a sufficiently expanded extraforaminal outlet, and the nerve roots were adequately decompressed.

LIMITATIONS: The study involved a relatively small number of samples and a short follow-up period.

CONCLUSIONS: The full endoscopic decompression surgery via the L5 transverse process-sacral ala pseudoarthrosis approach can address the extraforaminal compression in FOS. This procedure is a feasible endoscopic surgical option that serves as a valuable supplement to the minimally invasive treatment for FOS.

KEY WORDS: Full endoscopy, far-out syndrome (FOS), pseudoarthrosis, spine surgery, minimally invasive surgery, nerve entrapment, low back pain, radiculopathy