Zista system for minimally invasive treatment of lumbar spinal stenosis

Objective To evaluate the clinical efficacy of the minimally invasive treatment with Zista system for lumbar spinal stenosis. Methods April 2016 to October 2017, 45 patients with lumbar spinal stenosis (2 or 3 segments) were retrospectively collected, including 21 males and 24 females. Age 50-74 years, average 62.5 ±11.2 years, which were divided into mini-invasive surgery group and open surgery group. In the mini-invasive group, 19 cases were treated with mini-invasive decompression and intervertebral fusion internal fixation through Zista channel, including 14 cases with two segments and 5 cases with three segments. 26 cases were treated with traditional open surgery, 17 cases in two sections and 9 cases in three sections. The Japanese Orthopaedic Association score (JOA) and visual analogue scale (VAS) were used to assess the clinical effect postoperatively. The change of spinal canal in the mini-invasive group was assessed by lateral recess angle. Results All of the 45 operations had been completed successfully. The average operation time in mini-invasive surgery group was 240±15 min (range, 230-310) for 2 segments and 320±15 min (range, 320-370) for 3 segments. The average operation time in open surgery group was 255±15 min (range, 210-300) for 2 segments and 315±20 min (range, 330-390) for 3 segments, there was no significant difference between two groups. The intraoperative blood loss in mini-invasive surgery group was 220±25 ml (range, 190-310) for 2 segments and 340±30 ml (range, 280-410) for 3 segments. The intraoperative blood loss in open surgery group was 550±25 ml (range, 500-730) for 2 segments and 840±20 ml (range, 750-920) for 3 segments, the bleeding volume of the open surgery group was more than that of the mini-invasive group. All patients were followed up, and the follow-up time was 7.3±3.2 months (range, 3-12 months) in mini-invasive surgery group and 8.1±2.6 months (range, 3-12 months) in open surgery group respectively. The VAS score of low back pain and lower limb pain in the two groups was decreased 4.2 and 5.4 in mini-invasive group, 4.7 and 5.1 in open surgery group at 3 months after operation. The average JOA score of the two groups increased 13.3 in mini-invasive group and 12.7 in open surgery group at 3 months after the operation. The latera recess angle in mini-invasive group between preoperation and postoperation was significantly different. No incisional infection, implant loosening, discitis and leakage of cerebrospinal fluid were found. Conclusion Mini-invasive decompression and internal fixation through Zista channel for lumbar spinal stenosis is a safe, effective and minimally invasive method of operation with the characteristics of short operation time, less intraoperative blood loss and low complications. Key words: Lumbar vertebrae; Spinal stenosis; Surgical procedures, minimally invasive; Spinal fusion