Impact of optical navigation variables on the accuracy of robot-assisted surgery: a study of the TIANJI Robot system.

This study aims to explore factors related to optical navigation that interfere with the accuracy of robot-assisted surgery, specifically focusing on the TIANJI Robot system. A measurement model was created to assess the accuracy of the TIANJI Robot system in simulated screw placement. Deviation between actual and planned positions was measured using a three-coordinate machine. Various experiments were conducted to investigate the impact of different optical navigation factors on screw placement accuracy. Deviations were measured at different distances (ranging from 1.2 to 2.2 m) between the optical navigation stereo camera and the tracker, with each distance being tested 50 times. The distance between the optical camera and patient tracker was set at 1.4 m. Deviations were also measured at different angles between the camera and robot tracker, repeated over 25 times for each angle. Data were analyzed using mean and standard deviation, with line charts illustrating deviation changes based on distance and angle details. Within the range of the TIANJI Robot system's optical navigation (1.2-2.2 m), deviation increased as distance increased (χ2 = 479.107, P < 0.001). The robotic system demonstrated high and consistent accuracy (mean deviation: 0.332 mm ± 0.067 mm) when the relative angle between the optical camera and tracker was below 40°. The accuracy of the TIANJI Robot system was found to be influenced by relative distance and angle between the optical camera and tracker during screw placement procedures. Surgeons are recommended to set a relative distance of 1.4-1.5 m between the optical camera and patient tracker, with a relative angle below 40° when placing and adjusting optical tracking devices.

Prevalence of Lumbar Spondylolisthesis in Middle-Aged People in Beijing Community.

OBJECTIVE: Lumbar spondylolisthesis (LS) is a common lumbar disease, and the prevalence of LS in different countries or regions was not consistent in the past. This study intends to make statistics on the prevalence of lumbar spondylolisthesis in middle-aged people in Beijing community. METHODS: This is an epidemiological study. 4548 people in Beijing community aged 50 to 64 years were recruited from the local communities by advertisements placed in housing estates and community centres for people to take part in a prospective cohort study from August from September 2013 to March 2014. There is no intervention on the subjects. RadiAnt DICOM Viewer is adopted to read the lateral CT positioning images of all the studied objects, adjust the image as bone window, observe and evaluate the slide of L1 to L5 vertebra in the lateral CT positioning image. RESULTS: Among the 4,548 subjects included in the study, 2,490 (54.75%) were male and 2,058 (45.25%) were female. A total of 785 subjects had lumbar spondylolisthesis, with a total incidence of 17.26%. There was no significant difference between prevalence of males and females in the subgroup 50-54 years old (13.55% males / 12.53% females) and 55-59 years old (14.77% males / 14.93% females). But the prevalence of LS in 60-64 years old females (28.57%) increased significantly, compared with 55-59 years old females (14.93%) and 60-64 years old males (18.76%). There were 847 levels that had slipped, L5S1 > L4/5 > L3/4 > L2/3 > L1/2. The retrolisthesis was the most, accounting for 61.51% (521/847), and the anterolisthesis was 38.49% (326/847), including anterolisthesis gradeI for 95.71% (312/326), anterolisthesis gradeII for 4.29% (14/326). Neither of anterolisthesis and retrolisthesis presented more than grade III. Among all the subjects, 318 had anterolisthesis, with a total incidence of 6.99%, and 467 subjects only had retrolisthesis. CONCLUSION: The total prevalence of LS in the middle-aged people in Beijing community was 17.26%, 15.98% in males and 18.80% in females, and women are more likely to suffer from LS after 60 years old.