ObjectiveTo investigate the effectiveness of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) assisted with microscope in treatment of lumbar spondylolisthesis. MethodsBetween January 2011 and June 2012, 52 patients with lumbar spondylolisthesis underwent MI-TLIF assisted with microscope. There were 29 males and 23 females with an average age of 46 years (range, 32-67 years). The median disease duration was 3.2 years (range, 3 months to 6 years). There were 38 cases of lumbar isthmic spondylolisthesis and 14 cases of degenerative spondylolisthesis; 12 cases had stenosis secondary to lumbar spondylolisthesis. The affected segments were L4, 5 (29 cases) and L5, S1 (23 cases). According to the Meyerding evaluating system, 24 cases were classified as degree I and 28 cases as degree Ⅱ. The visual analogue scale (VAS) score and Oswestry disability index (ODI)were used for clinical assessment, and the clinical effects were also analyzed by Macnab criterion at last follow-up. The radiographic data were used to evaluate reduction of spondylolisthesis, including slipping degree, slipping angle, and intervertebral space height. The fusion rate was assessed by Suk criterion. ResultsThe operations were performed successfully in all patients. No dural tear or cerebrospinal fluid leakage occurred during operation. The average operation time was 105 minutes; the average intraoperative blood loss was 225 mL; the average postoperative drainage volume was 75 mL; and the average hospitalization days were 5.5 days. Superficial infection of incision occurred in 1 case and was cured after change dressing, and primary healing of incision was obtained in the others. All patients were followed up 12-26 months (mean, 18 months). No loosening, breakage, and displacement of pedicle screw and no Cage dislocation occurred by X-ray films after operation. The lumbar spondylolisthesis all got good correction. The three-dimensional CT showed continuous bone trabecula between centrums. The VAS score, ODI, and the slipping degree, slipping angle, and intervertebral space height were significantly improved at last follow-up when compared with preoperative ones (P<0.05). According to Macnab criterion at last follow-up, the results were excellent in 20 cases, good in 29 cases, and fair in 3 cases; the excellent and good rate was 94.2%. According to Suk criterion for fusion, 49 cases obtained complete fusion and 3 cases got possible fusion. ConclusionAs long as indications are seized, MI-TLIF assisted with microscope is safe and reliable for treatment of lumbar spondylolisthesis (Meyerding dergee I or Ⅱ), and it has the advantage of less injury, less blood loss, less complications, and definite short-term effectiveness.