A retrospective study of patients treated by transforaminal lumbar interbody fusion (TLIF) with
local bone graft alone for single-level isthmic spondylolisthesis (IS) between April 2009 and July 2014 in a single facility.
Methods: Demographic and operative data, complications, preoperative and postoperative clinical records, and
radiographs were revised. The Visual Analogue Scale (VAS) and Denis Work Scale were used for clinical and functional
assessment. Modified Lee et al. classification was used for assessment of union.
Results: Twenty-three patients with mean age of 45.04 6 7.19 years had single-level TLIF with local bone graft
alone for symptomatic IS with mean follow-up period of 28.39 6 4.01 months and mean operative time of 170.09 6
11.22 minutes. The VAS and Denis Work Scale improved from 8.48 6 0.58 and 4.67 6 0.47 preoperative to 2.91 6 1.25
and 1.33 6 0.58 at the latest follow up, respectively. Anterior vertebral translation improved from 27.22 6 9.54%
preoperatively to 8.38 6 3.63% postoperatively and 10.39 6 3.49 at the latest follow up. Disc space height was 9.67 6
5.55% preoperatively, 21.60 6 4.11% postoperative, and 16.24 6 4.02% at the latest follow up. Lumbar lordosis
improved from 29.39 6 10.338 to 45.13 6 6.848 postoperatively and 39.96 6 7.528 at the latest follow up. Eighteen
patients had definitive union, 4 patients with possible union, 1 patient with possible pseudoarthrosis.
Conclusions: Transforaminal lumbar interbody fusion with local bone graft alone is an appropriate option for
single-level IS, yet we do not recommend it for higher grades of slippage with anterior vertebral translation more than
25%.