Objective:To evaluate the risk factors for adjacent vertebral compression fracture (AVCF) after fusion surgery of lumbar canal stenosis in the elderly.Methods:A retrospective cohort study was designed for 297 patients with lumbar canal stenosis who underwent fusion surgery in Hubei Provincial Hospital of Integrated Chinese and Western Medicine from January 2017 to December 2020. There were 42 males and 255 females, aged 68-85 years [(76.3±7.2)years]. The patients were divided into AVCF group ( n=67) and non-AVCF group ( n=230) according to with or without the occurrence of AVCF. The indicators recorded were the gender, age, body mass index, education level, number of combined basic diseases, course of the disease, preoperative bone mineral density, intraoperative bleeding volume, number of level fused during operation, postoperative blood transfusion volume, postoperative observation in the ICU, types of postoperative external fixation and time of external fixation. Univariate analysis was conducted to analyze the correlation between above risk factors and AVCF after fusion surgery of lumbar canal stenosis in the elderly. Multivariate Logistic regression analysis was used to determine the independent risk factors for the occurrence of AVCF in these patients. Results:In the univariate analysis, age, education level, preoperative bone mineral density, intraoperative bleeding volume, postoperative blood transfusion volume and postoperative observation in the ICU were correlated with AVCF after fusion surgery of lumbar canal stenosis in the elderly ( P<0.05 or 0.01), while there was no correlation of AVCF with gender, body mass index, number of combined basic diseases, course of the disease, number of level fused during operation, types of postoperative external fixation and time of external fixation (all P>0.05). Multivariate Logistic regression analysis showed that gender ( OR=4.02, 95% CI 1.35, 12.00, P<0.05), preoperative bone mineral density≤-2.5 SD ( OR=2.01, 95% CI 1.47, 2.75, P<0.01), intraoperative bleeding volume≥475 ml ( OR=1.01, 95% CI 1.00, 1.01, P<0.01) and postoperative blood transfusion volume≥434 ml ( OR=0.99, 95% CI 0.98, 1.00, P<0.01) were significantly associated with AVCF after fusion surgery of lumbar canal stenosis in the elderly. Conclusion:The female, bone mineral density≤-2.5 SD, intraoperative bleeding volume≥476 ml and postoperative blood transfusion volume≥434 ml are independent risk factors for AVCF after fusion surgery of lumbar canal stenosis in the elderly.

Control at beyond-visual ranges is of great significance to animal-robots with wide range motion capability. For pigeon-robots, such control can be done by the way of onboard preprogram, but not constitute a closed-loop yet. This study designed a new control system for pigeon-robots, which integrated the function of trajectory monitoring to that of brain stimulation. It achieved the closed-loop control in turning or circling by estimating pigeons' flight state instantaneously and the corresponding logical regulation. The stimulation targets located at the formation reticularis medialis mesencephali (FRM) in the left and right brain, for the purposes of left- and right-turn control, respectively. The stimulus was characterized by the waveform mimicking the nerve cell membrane potential, and was activated intermittently. The wearable control unit weighted 11.8 g totally. The results showed a 90% success rate by the closed-loop control in pigeon-robots. It was convenient to obtain the wing shape during flight maneuver, by equipping a pigeon-robot with a vivo camera. It was also feasible to regulate the evolution of pigeon flocks by the pigeon-robots at different hierarchical level. All of these lay the groundwork for the application of pigeon-robots in scientific researches.
Animals ; Columbidae/physiology* ; Robotics/methods* ; Cerebral Cortex