[Treatment of ankylosing spondylitis with thoracolumbar fractures by robot-assisted internal fixation in lateral decubitus position].

Objective: To explore the effect of robot-assisted internal fixation in lateral decubitus position for the treatment of ankylosing spondylitis (AS) complicated with thoracolumbar fractures.

Methods: The clinical data of 26 patients with ankylosing spondylitis complicated with thoracolumbar fractures treated from January 2018 to June 2020 was retrospectively analyzed. According to different surgical methods, these patients were divided into observation group and control group. There were 8 patients in observation group, which were treated with robot-assisted percutaneous screw fixation in lateral decubitus position, including 4 males and 4 females, aged form 55 to 85 years old with an mean of (66.25±9.42) years, the course of disease was (4.00±0.76) days on average, 2 cases were T fracture, 2 cases were T, 3 cases were L and 1 case was L. And there were 18 patients in control group, which were treated with conventional percutaneous screw fixation in prone position, including 6 males and 12 females, aged from 48 to 81 years old with a mean of (61.22±9.53) years, the course of disease was (4.11±0.83) days on average, 2 cases were T injury, 3 cases were T, 4 cases were T, 7 cases were L, and 2 cases were L. The intraoperative blood loss, operation time, position time and postoperative neurological complications were compared between two groups. Postoperative visual analogue scale (VAS) at 1d and 3 months, and Oswestry Disability Index (ODI) before and 3 months after operation were observed. According to Gertzbein-Robbins standard to evaluate the accuracy of pedicle screw placement.

Results: There was no nerve injury due to pedicle screw placement in both groups. The intraoperative blood loss in observation group and control group was (34.13±4.61) ml and (78.17±22.02) ml, operation time was(92.13±9.82) min and (106.22±11.55) min, position time was(10.00±2.14) min and (15.17±2.66) min, the differences was statistically significant(<0.05);VAS of the two groups were (2.38±0.52) points and (4.56±0.98) points one day after surgery, respectively, with statistically significant differences (<0.05), while VAS and ODI three months after surgery showed no statistically significant differences (>0.05). The screw accuracy was 96.88%(62/64) in observation group and 81.48%(88/108) in control group, the difference was statistically significant(<0.05).

Conclusion: Robot-assisted internal fixation in lateral decubitus position for the treatment of ankylosing spondylitis complicated with thoracolumbar fractures can shorten the position time and operation time, significantly improve the accuracy of internal fixation screw placement, relieve the early postoperative pain, reduce intraoperative blood loss and postoperative complications, and facilitate the fast track rehabilitation of patients.