Evaluation of Treatment Effect of Minimally Invasive Spinal Fusion Surgery

After receiving prophylactic antibiotics according to the local hospital protocol, the patients were generally anesthetized in a prone position. Paramedian or midline posterior sections were conducted, exposing the lumber vertebras encompassing the facet joints. The facet joints were removed, and decompression was performed. The diseased disc nucleus was then excised before filling in the bone substitutes. For the control group, the bone substitutes were filled in the disc space manually using a bone grafting funnel. In the case of device group, a novel filler tube with integrated threaded rod, which can be connected to a surgical drill, was used for rapid and continuous graft filling (Figure 1). A polyethyletherketone (PEEK) interbody fusion cage was then placed into the disc space followed by fixation with pedicle screws. The treatment efficacy was assessed by clinical analysis based on the visual analogue scale (VAS) for radicular pain and the Oswestry Disability Index (ODI) questionnaire for low back pain. The VAS back and leg pain scores were measured preoperatively and postoperatively at 1, 3, 6, 12, and 24 months. The ODI questionnaires were taken preoperatively and postoperatively at 3, 6, 12, and 24 months. The bone graft delivery volume and the filling time during the surgery were measured to compare the efficiency of the two approaches.

The X-ray and computed tomography were performed prior to surgery and at 3-, 6-, 12-, and 24-monthspost-surgery for bone fusion assessment. The degree of bone fusion was classified into three grades. Grade I was defined as a complete fusion, union case, and grade II and III was defined as a partial union and a non-union case, respectively. Bone fusion volume was further determined by three-dimensional reconstruction images using ITK-SNAP software