Two-Year Radiological Fusion Outcomes Following Biportal Endoscopic Transforaminal Lumbar Interbody Fusion Using Banana-Shaped Interbody Cages.

Background

Biportal endoscopic transforaminal lumbar interbody fusion (BESS-TLIF) is an emerging minimally invasive technique. This study aimed to evaluate the two-year radiological fusion outcomes of single-level BESS-TLIF using a specific banana-shaped, porous titanium interbody cage.

Methods

This retrospective study reviewed 51 patients who underwent the specified procedure. The primary endpoint was the radiological fusion rate, assessed by computed tomography (CT) over 24 months using a three-grade system. Factors influencing fusion, particularly bone graft composition (demineralized bone matrix [DBM] only vs. DBM with I-factor), were also analyzed.

Results

The final complete fusion rate at two years was 96.1% (49/51; 95% Confidence Interval (CI), 86.5-99.5%). Bony fusion occurred predominantly in the posterior and intracage regions. The only significant factor influencing fusion was the bone graft material. The 'DBM with I-factor' group achieved complete fusion significantly faster than the 'DBM only' group (log-rank test, p < 0.001), with a higher final fusion rate (100% vs. 83.3%, p = 0.045).

Conclusions

Single-level BESS-TLIF using a banana-shaped, porous titanium cage provides favourable two-year radiological fusion rates. The selective addition of I-factor as an osteoinductive supplement can significantly accelerate the time to achieve solid arthrodesis.