Arthroscopy-assisted unilateral single-portal surgery for transforaminal lumbar interbody fusion (AUSS- TLIF) is an innovative minimally invasive spinal technique that combines the magnified visual field of endoscopy with the flexibility and efficiency of open surgery. This study is the first to prospectively compare the perioperative parameters, clinical outcomes, and radiographic results between AUSS- TLIF and uniportal full-endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) for single-level lumbar spinal stenosis with segmental instability, aiming to provide comprehensive evidence-based guidance for surgical technique selection.

Methods: Eighty patients meeting the inclusion criteria between March 2024 and March 2025 were allocated to either the AUSS-TLIF group (n=40) or the Endo-TLIF group (n=40) based on the surgical procedure. Operative time, intraoperative blood loss, length of hospital stays, and complication rates were compared. Clinical efficacy was evaluated using the Visual Analog Scale (VAS) for pain, the Oswestry Disability Index (ODI), and the Japanese Orthopaedic Association (JOA) score. Radiographic assessments included disc height, segmental lordosis angle, and interbody fusion rate. The minimum follow-up was 12 months.

Results: The Endo-TLIF group showed significantly less intraoperative blood loss (45.2±10.5 mL vs. 85.8±20.3 mL, P<0.05) and a shorter postoperative hospital stay (3.8±0.9 days vs. 4.5±1.2 days, P<0.05) compared to the AUSS-TLIF group. However, operative time was significantly shorter in the AUSS- TLIF group (118.5±25.6 min vs. 142.3±30.4 min, P<0.05). Postoperative VAS, ODI, and JOA scores improved significantly in both groups at all follow- ups compared to preoperative values (P<0.01), with no significant intergroup differences (P>0.05). At the final follow-up, no significant differences were found in the fusion rates (92.5% for AUSS-TLIF vs. 90.0% for Endo-TLIF) or radiographic parameters (P>0.05). The overall complication rates were similar (12.5% vs. 15.0%), but the complication profiles differed.

Conclusion: Both AUSS-TLIF and Endo-TLIF are safe and effective ultra-minimally invasive techniques for treating lumbar spinal stenosis with instability. Endo-TLIF demonstrates advantages in minimizing blood loss and facilitating faster recovery, reflecting its “extreme minimally invasive” nature, while AUSS-TLIF offers greater procedural efficiency. Both techniques achieve equivalent mid-term pain relief, functional improvement, and solid fusion.