Abstract
OBJECTIVE: The purpose of this study is to analyze the changes of spinal artery blood flow (SCBF) and its potential impact on the safety of spinal cord function during spinal deformity osteotomy by using laser speckle imaging technology, and to monitor the changes of vertebral artery flow velocity and resistance index before and after operation by using color Doppler ultrasound technology, so as to preliminarily explore the correlation between vertebral artery and spinal cord vascular hemodynamic changes, and to explore the safety limit of osteotomy shortening. METHODS: The volunteers were divided into Group A and Group B according to their needs. Group A included 8 patients with spinal deformity who underwent vertebral artery ultrasound examination before and after spinal deformity correction surgery. Group B also included 8 patients with spinal deformity who underwent spinal osteotomy and 1/3 and 1/2 shortening of the spine, and 5 patients underwent 1/3 spinal distraction. Intraoperative laser speckle imaging system was used to monitor the changes of spinal cord blood perfusion and vascular diameter in real time, and the spinal cord function was evaluated with the help of neurophysiological monitoring. All patients in the study received SRS-22 and ODI scores before and after surgery; Rstudio software was used for statistical analysis. RESULTS: In Group A, the postoperative vertebral artery flow velocity of 8 patients increased to varying degrees compared with that before operation, and the resistance index decreased or leveled to varying degrees, the difference was statistically significant (P < 0.05). In Group B, the SCBF of the left and right spinal arteries decreased to varying degrees after traction, and the diameter of spinal artery increased gradually with the increase of traction degree. In Group B, the SCBF of the left and right spinal artery increased first and then decreased after osteotomy and 1/3 and 1/2 spinal shortening, and the diameter of spinal artery gradually increased with the increase of shortening degree, the difference was statistically significant (P < 0.05). The SRS -22 scale and ODI scores of all patients before and after operation were significantly different (P < 0.05). Further analysis showed that there was a significant correlation between the SCBF of bilateral spinal artery and the diameter of bilateral spinal artery before and after 1/3 spinal distraction and 1/3 spinal shortening (P < 0.05). There were correlations between bilateral vertebral artery resistance index and flow velocity, SCBF and ODI scores, bilateral spinal artery diameter, and bilateral vertebral artery resistance index before and after operation (P < 0.05). However, there was no significant correlation between the SCBF of bilateral spinal cord blood vessels and the diameter of bilateral spinal cord blood vessels when the spine was shortened by 1/3 to 1/2 (P > 0.05). During the whole operation, no abnormality was found in the electrophysiological monitoring. CONCLUSION: In the process of spinal traction and shortening, the diameter of spinal cord blood vessels decreased and gradually increased. The pulling operation will lead to the decrease of SCBF, while the shortening operation will make the SCBF increase first and then decrease. Before and after operation, there were significant correlations between the resistance index and flow velocity of bilateral vertebral artery, SCBF and ODI scores, and the diameter of bilateral spinal artery and the resistance index of bilateral vertebral artery. When the degree of spinal shortening is controlled within 1/3 of that after single vertebral osteotomy in the lower thoracic spine, the change of SCBF is positively correlated with the increase of spinal cord vascular diameter, and the shortening of less than 1/2 after single vertebral osteotomy in the lower thoracic spine can be regarded as the safety threshold.