Percutaneous Endoscopic Robot-Assisted Transforaminal Lumbar Interbody Fusion (PE RA-TLIF) for Lumbar Spondylolisthesis: A Technical Note and Two Years Clinical Results

Background: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and percutaneous endoscopic TLIF (PE-TILF) have been widely used in spine surgery. The use of a robot-guided technique provided several advantages; however, few studies have investigated the clinical outcomes of robot assisted PE-TLIF (PE RA-TLIF). Objective: The aim of this prospective cohort study was to compare the clinical outcomes of PE RA-TLIF with MIS-TLIF for the treatment of lumbar 4-5 (L4-5) spondylolisthesis. Study Design: Prospective cohort study. Setting: Qilu Hospital of Shandong University. Methods: Fifty-eight cases diagnosed with L4-5 spinal stenosis with instability and Meyerding grade I spondylolisthesis (degenerative spondylolisthesis or isthmic spondylolisthesis) were included in this study. Twenty-six patients (group A) were treated with PE RA-TLIF, and the others (group B) underwent MIS-TLIF. The surgical procedures for PE RA-TLIF included the percutaneous implantation of pedicle screws (PS) under robot guidance, percutaneous fully endoscopic transforaminal decompression, and interbody fusion. The Japanese Orthopedic Association (JOA) score, the visual analog scale (VAS) for low back pain (LBP), the VAS for leg pain/numbness, and the Oswestry disability index (ODI) were used as follow-up clinical outcomes, and the lumbar interbody fusion rate was evaluated by CT. All statistical analyses were performed with SPSS 22.0, and the results were presented as mean +/- standard deviation (SD). Results: There were 4 cases of spinal stenosis with instability, 17 cases of degenerative spondylolisthesis, and 5 cases of isthmic spondylolisthesis in group A. For group B, there were 6 cases of spinal stenosis with instability, 19 cases of degenerative spondylolisthesis, and 7 cases of isthmic spondylolisthesis. The preoperative scores for the JOA, ODI, VAS for LBP, and VAS for leg pain were not statistically comparable between the 2 groups (P > 0.05). The incision length for decompression and interbody fusion, estimated blood loss (EBL), and 1-day and 3-day incision pain were significantly higher in group B than in group A (P < 0.05). The mean operative time was longer in group A than in group B (P < 0.05). The operation time of the first 10 cases (251 +/- 24 min) was much longer than that of the last 16 cases (200 +/- 17 min) in group A. The misplacement rate of percutaneous pedicle screw placement was higher in group B (P < 0.05). No infections of incisions and interbody or nerve root or dural injuries were found in either group A or B. No differences were found between the 2 groups in the JOA scores, ODI, leg pain VAS score, or lumbar interbody fusion rate at the 2-year follow-up. The VAS for back pain was better in group A than in group B (P < 0.05). Limitations: The PE RA-TLIF procedure is technically challenging and has a steep learning curve, and the study was not strictly randomized. Conclusion: PE RA-TLIF is a safe and effective procedure that can significantly improve the accuracy of pedicle screw placement, reduce surgical trauma, and facilitate rapid postoperative recovery. However, this technique has a steep and long learning curve and requires long-term follow-ups.