Difference Of Sound Pressure Signal From Bone Drilling Of Circumferential Resection Of Articular Processes In Thoracic Spine

ObjectiveTo analyze the difference of sound pressure signal from bone drilling of circumferential resection of articular processes in thoracic spine.Material and MethodsFive mini-pigs underwent the circumferential resection of articular processes on T9-T10 levels which were performed hole by hole with the engagement of a high-speed burr 4 mm in diameter.After the posterior structures were adequately exposed,the spinous processes of T8、 T9 and T10 were removed with a rongeur;then the lamina of T9 connected with inferior articular processes was drilled from the base of spinous process to the bony connection between the lamina and vertebral pedicle bilaterally;the connection between inferior articular processes and vertebral pedicles were cutting completely.Then the lamina of T10 was drilled from the base of spinous process to the bony connection between the lamina and vertebral pedicle bilaterally.the connection between superior articular processes and vertebral pedicles were also cutting completely.The lateral articulations were completely freed from adjacent vertebrae and removed.During the surgical process,the drilling sound pressure signal of ventral cortical bone and penetration was record by a high precision microphone and a dynamic signal analyzer.The Lifting wavelet transform of MTALAB software was applied to decompose the recorded sound pressure signal and the harmonic components were extracted from the sound pressure signal to correlate drilling condition.Harmonics are the most important component of sound pressure signal whose frequencies are integer multiples of spindle frequency of the high-speed burr(1000Hz,2000 Hz,3000Hz,4000 Hz,and 5000Hz).The modulus of sound pressure signal was compared at each frequency to determine whether ventral cortical bone was drilled or penetration.The independent sample T test was applied for the statistical analysis.When P < 0.05,it can be considered that there is significant difference.ResultsThe circumferential resection of articular processes was performed successfully on each specimen and the sound pressure signal of each drilling process was collected continually and analyzed.The data suggest that when the laminae of T9 and T10 were drilled,the modulus of sound pressure signal of ventral cortical bone was higher than that of penetration and significant difference could be found at 1000 Hz,2000Hz,3000 Hz,4000Hz,and 5000 Hz frequencies(P < 0.05).When the lateral articulations were drilled,the modulus of sound pressure signal of ventral cortical bone was higher than that of penetration and there were significant differences at the frequencies of 1000 Hz,2000Hz,3000 Hz,4000Hz,and 5000Hz(P < 0.05).ConclusionDuring the circumferential resection of articular processes in thoracic spine,on matter the laminae or the lateral articulations were drilled,the sound pressure signal of ventral cortical bone is significantly higher than that of penetration at each frequency point.Therefore,the sound pressure signal could be potentially helpful to identify the different drilling statues and improve the safety of circumferential resection of articular processes in thoracic spine.