Comparison of biportal endoscopic vs minimally invasive transforaminal lumbar interbody fusion for single-level low-grade lumbar spondylolisthesis: A retrospective cohort study

Figure 1 Key steps of biportal endoscopic transforaminal lumbar interbody fusion procedure, shown in chronological order. A: Exposure of the ligamentum flavum after soft tissue clearance using radiofrequency plasma; B: Resection of the inferior edge of the lamina with a Kerrison rongeur; C: Resection of the medial aspect of the facet joint (white arrows indicate the resected facet margin), with exposure of the dural sac; D: Protection of the traversing nerve root, with the underlying disc exposed; E: Endplate preparation after discectomy (white arrows indicate the prepared endplate surface); F: Insertion of a trial implant to determine the appropriate cage size; G: Placement of the interbody cage under endoscopic guidance; H: Final pedicle screw and rod fixation confirmed by intraoperative fluoroscopy.