Clinical and radiological outcome of stand-alone percutaneous pedicle screw fixation (SAPF) versus minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). A propensity-matched cohort study

: In adult patients affected by degenerative disc disease with lumbar instability and chronic low back pain, spine surgery with lumbar fixation aims to reduce segmental instability and pain. Different techniques have been developed, but the optimal surgical technique remains controversial. No studies have compared the clinical and radiological outcomes between stand-alone pedicle screw fixation (SAPF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). This was a retrospective study. All patients who underwent surgery for single-level L4-L5 or L5-S1 lumbar stenosis, associated with minor lumbar instability and treated with SAPF or MI-TLIF techniques were included in the study. Data were collected preoperatively and at 24 monts follow-up. Clinical primary outcomes were Oswestry Disability Index (ODI) and Numerical Rating Scale (NRS). Secondary outcomes were patient satisfaction, walking ability and self reported back and leg pain. In addition, perioperative data and complications were recorded. Segmental lordosis (L4-L5 and L5-S1) and overall lumbar lordosis (L1-S1) were measured on lumbar X-Rays preoperatively and at least 24 months postoperatively. 277 patients were firstly identified. Baseline data and a minimum of two-year follow-up were available for 62 patients. After the propensity score matching, 44 patients (22 patients in the SAPF group and 22 patients in the MI-TLIF group) were matched. At 24 months follow-up, no difference between the two groups of patients in NRS (p = 0.11) and ODI scores (p = 0.21) were observed. Patients' satisfaction at follow-up was also not significantly different between the two groups. In both groups, a significant improvement in the walked distance was observed after surgery (p = 0.05) while no difference was observed regarding the type of surgery performed (p = 1.00). No differences were found in the pre- and post-operative median lumbar lordosis (p = 0.91 and p = 0.67) and the same findings were observed for lumbar segmental lordosis (p = 0.65 and p = 0.41 respectively). Significant improvements in ODI and NRS-scores were recorded after 24 months follow-up with both SAPF and MI-TLIF. No significant differences in postoperative PROMs and patients' satisfaction were observed between the groups. The results of our study indicate no superiority of either surgical technique concerning pain and functional outcomes after 24 months.