Recently, favorable results of minimally invasive spinal surgery have been reported in comparison to the open decompression or fusion surgery. Biportal endoscopic spine surgery (BESS) has several benefits and Indications for BESS are nearly identical to those for general open spinal surgery. However, it remains a challenging procedure even for an experienced endoscopic surgeon. because it takes a a long operation time while early learning period. If the operation time is prolonged, the advantages of endoscopic surgery are reduced and the incidence of complications can be increased. Therefore, we will investigate the factors affecting the operation time and how to minimize it before and during operation.

Purpose
of Study: Purpose of this study is to summarize the technique of UBE surgery in lumbar interbody fusion and review the clinical outcomes and complications of UBE surgery in lumbar interbody fusion.
Materials and Methods
Medical databases were searched for the key words of unilateral biportal endoscopic surgery and lumbar spinal stenosis using PubMed from 2005 to the present.
Conclusion
UBE spinal surgery is a new technique that can be a feasible alternative and an effective treatment modality for spinal degenerative diseases and can achieve the necessary surgical skills for experienced microscopic surgeons, which is still expanding the indications for lumbar spinal surgery.