RESUMO
BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has become one of the standard techniques for approaching ipsilateral decompression, anterior column fusion, and posterior stabilization. This procedure is usually accompanied by the placement of bilateral transpedicular screws in the corresponding segment. The purpose of this study was to evaluate the clinical efficacy of unilateral screw fixation compared with bilateral fixation in patients diagnosed with low-grade symptomatic lumbar spondylolisthesis who underwent an MI-TLIF technique. METHODS: A prospective and comparative study was performed in 67 patients with grade 1 symptomatic lumbar spondylolisthesis. The sample was allocated on both unilateral fixation group (n=33) and bilateral fixation group (n=34). Clinical outcomes were evaluated using Oswestry Disability Index (ODI), visual analogue scale (VAS) for leg and back pain, and Short Form 36 Health Survey (SF-36), preoperatively, and at 1, 3, 6, and 12 months postoperatively. Changes over time and differences between the groups were analyzed. Statistical analyses included: Friedman test, Student's t-test and Mann-Whitney's U. A two-tailed P value of <0.05 was considered significant. RESULTS: During 1-year of evaluation there were no significant clinical differences between both groups. CONCLUSIONS: Patients with grade 1 symptomatic lumbar spondylolisthesis treated with MI-TLIF with unilateral screw fixation had similar clinical results than those treated with bilateral fixation at 12 months postoperatively.
RESUMO
Various minimally invasive techniques have been reported as an alternative to conventional lumbar decompression. The major advantage of these minimally invasive procedures lies in their reduction of unnecessary exposure and tissue trauma. Our objective was to describe a minimally invasive procedure for lumbar spinal stenosis decompression by enlarging the lumbar interspinous space, approaching it with a tubular retractor, and assisting with microscopy. Thoracolumbar fascia and paravertebral muscles are preserved throughout the whole procedure. Iatrogenic instability of the spine can be avoided if during the procedure both joints are just undercut in order to decompress the subarticular space. The approach described in this manuscript could be used as an alternate minimally invasive surgical procedure for the treatment of central and lateral lumbar spinal stenosis.