The Result of Minimally Invasive Transforaminal Lumbar Interbody Fusion in Low Grade Spondylolisthesis - Minimum 2 Years Follow Up -

ABSTRACT

STUDY DESIGNS: A retrospective study. OBJECTIVES: To analyze the clinical and radiological outcomes of spontaneous reduction via minimally invasive transforaminal lumbar interbody fusion (Mini-TLIF) as the treatment for low-grade symptomatic spondylolisthesis. SUMMARY OF LITERATURE REVIEW: Although minimally invasive transforaminal lumbar interbody fusion is technically demanding, this procedure is an effective method for spontaneous reduction of low grade spondylolisthesis. MATERIALS AND METHODS: We analyzed consecutive series of 41 patients with low grade spondylolisthesis who underwent minimally invasive transforaminal lumbar interbody fusion, between April 2008 and July 2009. The minimum follow-up period was 2 years. Clinical evaluation was performed by an analysis of Visual Analogue Scale and Oswestry Disability Index. For the radiological evaluation, disc space height, slip percentage, and slip angle were analyzed. At the final follow-up, the fusion rate was analyzed according to the Bridwell's anterior fusion grade. RESULTS: For the evaluation of clinical outcomes, the Visual Analogue Scale for back pain decreased from 6.8+/-1.2 to 2.0+/-1.1, and that for radiating pain decreased from 7.9+/-1.3 to 1.7+/-1.1. Oswetry Disability Index decreased from 38.5+/-8.4 to 13.4+/-6.1. For the radiological evaluation, disc space height increased from 8.4+/-2.14mm to 11.8+/-1.54mm(P<0.05), slip percentage was reduced from 18.4+/-5.1% to 13.3+/-3.1%(P<0.05) and slip angle decreased from 10.6+/-4.5degrees to 6.2+/-3.4degrees (P<0.05). At the final follow-up, radiological union was obtained in 38 cases (92.7%). CONCLUSIONS: We conclude that minimally invasive transforaminal lumbar interbody fusion appears to be an effective method for spontaneous reduction of low grade spondylolisthesis if the surgeon becomes familiar with this method.