Transforaminal Lumbar Interbody Fusion Using Wedged Cages for Isthmic Spondylolisthesis: A Short-Term Radiological Analysis

ABSTRACT

OBJECTIVE: The ability to induce segmental lordosis has been reported to be marginal with transforaminal lumbar interbody fusion(TLIF). Therefore, we analyzed the short-term radiological outcomes of TLIF using 8 degrees wedged cages for isthmic sp-ondylolisthesis. METHODS: Twenty-seven patients with isthmic spondyloisthesis who underwent single level TLIF with pedicle screw fixation (PSF) using 8 degrees wedged cages were retrospectively evaluated. Changes in disc height, degree of anterolisthesis, segmental lumbar lordosis, whole lumbar lordosis and L1 axis S1 distance were evaluated using standing lateral radiographs before surgery, at 6 weeks follow-up and at the final follow-up. RESULTS: The mean age of the patients was 49.9 years (range, 38 to 64 years). The affected levels were L4-5 in 17 cases and L5-S1 in 10. There were 18 cases of Grade I isthmic spondylolisthesis and 9 cases of Grade II. At a mean follow-up duration of 9.9 months (range, 6 to 18 months), the disc height (p<0.001) was significantly increased, and the degree of anterolisthesis was significantly reduced (p<0.001). Regarding the sagittal balance, the segmental lumbar lordosis was significantly increased (p=0.01), but other parameters were not significantly changed after surgery. CONCLUSION: TLIF with PSF using 8 degrees wedged cages significantly increased the segmental lumbar lordosis.