Percutaneous transforaminal endoscopic surgery (PTES) and mini-incision L5/S1 OLIF with a self-lock cage for the surgical treatment of L5 spondylolisthesis

OBJECTIVES: We reported thirteen cases of percutaneous transforaminal endoscopic surgery (PTES) under local anesthesia and mini-incision L5/S1 OLIF (OLIF51) with a self-lock cage for the treatment of L5 spondylolisthesis. METHODS: From Jan 2019 to Feb 2020, the patients with L5 spondylolisthesis with nerve root symptoms undergoing PTES and OLIF51 were included in this study. PTES under local anesthesia was performed in a prone position, and OLIF51 with a self-lock cage and allograft was then undertaken through a left abdominal mini-incision and oblique retroperitoneal approach between bilateral iliac vessels with the external oblique, internal oblique and transverse abdominal muscles bluntly separated in turn for L5/S1 in a right oblique position under general anesthesia. Back and leg pain were preoperatively and postoperatively evaluated using the VAS, and the clinical outcomes were evaluated with the ODI before surgery and at the 2-year follow-up. The anterior and posterior intervertebral space height (AISH, PISH), lumbar lordotic, and surgical segmental lordotic angle (SLA) were measured on lumbar spine X-rays preoperatively and postoperatively. The fusion status was assessed according to Bridwell’s fusion grades. RESULTS: Thirteen cases of L5 spondylolisthesis were included. The operation duration was 49.1 ± 5.6 min for PTES and 73.6 ± 8.2 min for OLIF. There was blood loss of 25 (15–45) ml. The incision length was 7.5 ± 1.1 mm for PTES and 46.8 ± 3.8 mm for OLIF. The hospital stay was 5 (4–6) days, and the follow-up duration was 29 (24–37) months. For the clinical evaluation, the VAS of back and leg pain significantly dropped after surgery (p < 0.001), and the ODI significantly decreased from 64.7 ± 7.8% to 12.9 ± 4.3% 2 years after surgery (p < 0.001). AISH, PISH and SLA significantly improved after surgery (p < 0.05). Fusion grades based on the Bridwell grading system at the 2-year follow-up were grade I in 9 segments (69.2%) and grade II in 4 segments (30.8%). No patients had any form of permanent iatrogenic nerve damage or major complications. No failure of instruments was observed. CONCLUSIONS: PTES and mini-incision OLIF51 with a self-lock cage is a viable option of minimally invasive surgery for L5 spondylolisthesis, which can achieve direct neurologic decompression, satisfactory fusion and hardly destroys the rectus abdominis and its sheath, paraspinal muscles and bone structures.