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Unilateral biportal endoscopic (UBE) spine surgery for spinal diseases has been increasing in popularity because of its favorable outcomes. The goal of this systemic review is to analyze the status of outcomes and complications in lumbar disc herniation during UBE discectomy.A comprehensive search of the PubMed, Embase, Web of Science, and OVID databases published until June 30, 2021, was performed. The outcomes of interest were indications, operative time, blood loss, hospital stay, complications, visual analog scale score, and Oswestry Disability Index.Seven studies were included in our research. UBE surgery for lumbar stenosis was excluded. A total of 230 patients with lumbar disc herniation were enrolled in the 7 selected studies. The mean operative time was 74.4 minutes, and the mean length of hospital stay was 4.5 days. Mean incidence of complications reported in the 7 articles was 6.2%. UBE showed shorter hospital stays than did microdiscectomy, no significant differences of Oswestry Disability Index or visual analog scale scores, and good recovery rate among other discectomy techniques (microdiscectomy, full endoscopic transforaminal endoscopic lumbar discectomy, and interlaminar endoscopic lumbar discectomy) at 1 month follow-up.Even with the small number of studies and reports analyzed, biases were the main limitation of this analysis; overall, the clinical outcomes and complication rates associated with UBE discectomy were relatively good. It is clear that UBE discectomy is a good treatment choice for lumbar disc herniation, but to prevent unique UBE surgery complications, a clear understanding of the surgical procedures and careful efforts to overcome the learning curve are necessary.

This study investigates the effect of stainless steel (STS) 308 L and high-entropy alloy (HEA) filler metals on gas tungsten arc (GTA) welding. The weldability of the cast CoCrFeMnNi HEAs was determined based on the microstructural and mechanical properties of the welds. The cast HEA exhibited larger dendrite packets than the weld metals (WMs). The hardness in the WM was superior compared with that in the base metal (BM). The WM using STS 308 L exhibited a fully face-centred cubic (FCC) structure with no indication of δ-ferrite and lower hardness than that using HEA filler. The GTA welds using both fillers showed tensile properties comparable to the cast BM at 298 K, and the tensile fracture of the transverse welds occurred near the cast BM. The cryogenic tensile properties in the GTA welds were superior compared with the room-temperature property due to the significant formation of deformation twins and high dislocation density at 77 K. This was probably due to the decrease in the stacking fault energy at the cryogenic temperature compared with that at the room temperature. Therefore, it is possible to apply commercial STS 308 L filler metal for the CoCrFeMnNi HEA in cryogenic applications.