To evaluate the clinical effectiveness of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for single-level lumbar spondylolisthesis treatment with bilateral Spotlight tubular channels.

A total of 21 patients with lumbar spondylolisthesis whom underwent MIS-TLIF via bilateral Spotlight tubular channels were retrospectively analyzed from October 2014 to November 2015. The 21 patients included 11 males and 10 females ranged from 35 to 82 years (average aged 60.7 years). In term of spondylolisthesis category, there were 18 cases of degenerative spondylolisthesis and 3 cases of isthmic spondylolisthesis. With respect to spondylolisthesis degree, 17 cases were grade Ⅰ° and 4 cases were grade Ⅱ°. Besides, 17 cases at L_4-5 and 4 cases at L₅-S₁were categorized by spondylolisthesis levels. Operation duration, blood loss, postoperative drainage and intraoperative exposure time were recorded, functional improvement was defined as an improvement in the Oswestry Disability Index (ODI), Visual Analog Scale (VAS) was also employed at pre and post-operation (3 months and the last follow-up), to evaluate low back and leg pain. Furthermore, to evaluate the recovery of the intervertebral foramen and of lumbar sagittal curvature, average height of intervertebral space, Cobb angles of lumbar vertebrae and operative segments, spondylolisthesis index were measured. At the last follow-up, intervertebral fusion was assessed using Siepe evaluation criteria and the clinical outcome was assessed using the MacNab scale. Radiographic and functional outcomes were compared pre- and post-operation using the paired T test to determine the effectiveness of MIS-TLIF. Statistical significance was defined as P<0.05.

All patients underwent a successful MIS-TLIF surgery. The operation time (235.2±30.2) mins, intraoperative blood loss (238.1±130.3) ml, postoperative drainage (95.7±57.1) ml and intraoperative radiation exposure (47.1±8.8) were recorded. Different significance between 3 months post-operative follow-up and pre-operation was exhibited (P<0.01) in respects of lumbar VAS (t=11.1, P<0.01) and leg VAS (t=17.8, P<0.01). Moreover, final follow-up compared with pre-operation, and final follow-up compared with 3 months post-operative follow-up, VAS scores were also statistical difference (P<0.01). At the final follow-up, there were significant differences compared with pre-operation in ODI scores (t=30.1, P<0.01). Comparison between 3 months post-operative follow-up and pre-operation, statistical distinctions were demonstrated (P<0.05) in terms of mean height of intervertebral space (t=-10.9, P<0.01), the Cobb angles of lumbar vertebrae (t=-2.4, P<0.05), operative segments Cobb angles (t=-5.2, P<0.01) and Lumbar spondylolisthesis incidence (t=17.1, P<0.01). In addition, there was statistical difference between final follow-up and pre-operation (P<0.05) as well. For instance, mean height of intervertebral space (t=-10.5, P<0.01), the Cobb angles of lumbar vertebrae (t=-2.7, P<0.05), operative segments Cobb angles (t=-4.2, P<0.01) and Lumbar spondylolisthesis incidence (t=18.6, P<0.01) were involved. All spondylolisthesis vertebrae were restored completely. Lastly, at the last follow-up, 12 cases of grade 1 and 7 cases of grade 2 fusion were present as determined by the Siepe evaluation criteria. McNab scale assessment classified 17 patients having excellent clinical outcome, 3 patients in good and 1 patient having a better clinical outcome.

MIS-TLIF with bilateral Spotlight tubular channels is a safe and effective approach for single segment lumbar spondylolisthesis.

Lumbar vertebrae; Surgical procedures, minimally invasive; Spinal fusion; Lumbar spondylolisthesis