Objective To evaluate the accuracy of the related parameters measured by spinal virtual surgery system (SVSS) three-dimensional (3D) techniques by comparing with the parameters measured by multi-spiral CT (MSCT) workstation. Methods Seven vertebrae specimens of adult men were scanned with MSCT, and the messages were sent toMSCT workstation and SVSS. The 3D image of spine was reconstructed by using volume rendering and multi-planar reformation; based on the parameter requirement of lower cervical pedicle fixation, 10 related parameters were measured. Then SPSS11.0 analyzer software was used to analyze the parameters measured by 2 systems. Between June 2009 and March 2010, 6 patients who received screw insertion in lower cervical spines were given MSCT scanning, then the messages were sent to SVSS 3D reconstruction to evaluate the situation and to collect the parameters of pedicle screw insertion. Results SVSS measurement showed that 1 pedicle was clausura (C3) and the diameters of 4 pedicles in coronal view were lee than 3 mm (C4 in 1, C5 in 2, C6 in 1), which did not fit for screw insertion; the results were similar to those by MSCT measurement. A total of 66 lower cervical pedicle were measured successfully. Significant differences were found in 14 parameters as follows between 2 systems (P lt; 0.05): the left pedicle height of C3, the both sides pedicle width of C4, the right pedicle spongy width of C4, the left X-direction entrance of C6, the both sides Y-direction entrance of C3, total pedicle length of sagittal view in both sides pedicle of C3 and the left pedicle of C5, total pedicle length of axial view in C3 pedicles, the left pedicle of C5, and the right pedicle of C6. There was no significantdifference in the other parameters (P gt; 0.05). In 6 cl inical cases, 34 screws were inserted, the postoperative MSCT scanning showed that 30 screws were placed successfully. The rate of accuracy was 88.24%. According to the Richter’s perforation classification, perforation at grade I and at grade II occurred in 2 cases (5.88%), respectively. Conclusion The accuracy of the parameters measured by SVSS is similar to that by MSCT.
Objective To employ spinal virtual surgery system (SVSS) for preoperative planning of thoracolumbar pedicle screw fixation, and to establ ish the measurement method for pedicle screw-related parameters. Methods Eight thoracicand lumbar spine specimens (T11-L3) were selected. First of all, SVSS was used for the preoperative planning of pedicle screw and the parameters of both sides of pedicle were measured in every vertebral segment, including angle of axial view (Aa), angle of sagittal view (As), x-direction entrance (XE), total pedicle length of axial view (TLa), total pedicle length of sagittal view (TLs), pedicle height (PH), pedicle width (PW), and pedicle spongy width (PSW). Then the corresponding parameters of the right and left pedicle screws of the specimens were measured actually. Finally, its accuracy was verified by comparing the data by virtual measurement and actual measurement. Results There was no significant difference in the parameters of virtual measurement (Aa, As, TLa, TLs, XE, PW, PSW, and PH) and actual measurement (Aa, As, TLa, XE, PW, PSW, and PH) between the right and left sides (P gt; 0.05). Except XE of the L3 vertebral segment and PSW of T11 and T12 vertebral segments (P lt; 0.05), the differences in other parameters of other segments were not significant (P gt; 0.05). Conclusion After statistical analysis and comparison, the feasibil ity of preoperative planning of thoracolumbar pedicle screw fixation and the accuracy of the measurement of the SVSS is verified.