Unilateral biportal endoscopy for minimally invasive spinal fusion: Advancements in biomaterials and clinical outcome optimization.

Lumbar interbody fusion is essential for treating degenerative lumbar diseases. The disadvantages of open surgery have led to the evolution of minimally invasive spine surgery, including endoscopic techniques such as unilateral biportal endoscopy (UBE). Leveraging arthroscopic principles, UBE offers superior visualization and flexibility and expands from decompression to fusion (UBE fusion). However, achieving robust UBE fusion presents challenges, such as suboptimal arthrodesis rates and implant-related complications, requiring more than surgical skill alone. Optimizing UBE fusion critically depends on the effective integration of advanced biomaterials with the surgical technique. This minireview assessed recent advances in UBE, focusing on the development of novel biomaterials, such as functionalized porous, expandable, or double-cage designs, to improve bone regeneration outcomes. These advancements address challenges, like washout of bone graft material and biologics, and utilize growth factors, such as recombinant human bone morphogenetic proteins, while exploring pathway modulation to improve outcomes. We also evaluated clinical optimization strategies involving technical refinements, fluid and hemostasis control, key complication mitigation especially concerning dural tears and hematomas, and technologies such as navigation and robotics. While UBE shows promise particularly for early recovery, its long-term success hinges on these biotechnological advancements. High-quality evidence, especially from randomized controlled trials and long-term studies, is needed to validate integrated strategies and define the optimal role of UBE fusion.