Quiñones-Hinojosa Alfredo, Robert Kolen E, Jun Peter, Rosenberg William S, Weinstein Philip R
Department of Neurological Surgery, University of California, San Francisco, USA.
J Spinal Disord Tech. 2006 Apr;19(2):109-13. doi: 10.1097/01.bsd.0000168513.68975.8a.
The integration of digital image-guided surgical navigation with C-arm fluoroscopy, known as virtual fluoroscopy (VF), has been shown to enhance the safety of spine surgery in vitro. Few clinical studies have assessed the accuracy of VF during actual spinal surgery, and no studies have investigated variations in accuracy over the course of a series of measurements obtained during operative cases. We sought to study the intraoperative accuracy of VF over time and space during lumbar pedicle screw placement in human patients.
Fluoroscopic images of the lumbar spine were obtained, calibrated, and saved to the Stealth Station (FluoroNav) on seven patients undergoing lumbar fusion surgery. The tracking arc was attached to an exposed lumbar spinous process, which was designated the index level. With use of anatomic surface irregularities in the laminae and spinous processes, several points were identified and registered on three different vertebrae directly adjacent to the index level vertebra. Every 15 minutes, throughout the operative case, the probe was brought to each point and the apparent distance from the original location recorded (as measured by the FluoroNav system). Measurements were collected from three vertebral levels adjacent to the index level over a time course of 120 minutes during the operation.
At the index, index +1, index +2, and index +3 levels, 89%, 81%, 92%, and 64% of measurements were within <2 mm, whereas 97%, 96%, 97%, and 91% were within <3 mm, respectively. At 15, 30, 45, 60, 75, 90, 105, and 120 minutes, 96%, 89%, 85%, 61%, 85%, 90%, 93%, and 50% of measurements were within <2 mm, whereas 100%, 93%, 100%, 83%, 100%, 90%, 100%, and 100% of measurements were within <3 mm, respectively. The error in millimeters tended to increase as the distance from the index level increased (R = 0.19, P < 0.05) and as operative time increased (R = 0.26, P < 0.01). Calibration studies of intraoperative VF (IoVF) in the lumbar spine documented a reasonable degree of accuracy. The majority of sequential measurements obtained during IoVF in the lumbar spine were within an error range of <3 mm.
Our results suggest that the use of VF is a reliable method of verifying the use of anatomic and/or radiographic landmarks for guidance during lumbar pedicle screw placement.
数字图像引导手术导航与C型臂荧光透视的整合，即虚拟荧光透视（VF），已被证明可提高体外脊柱手术的安全性。很少有临床研究评估实际脊柱手术中VF的准确性，也没有研究调查手术过程中一系列测量的准确性变化。我们试图研究人类患者腰椎椎弓根螺钉置入过程中VF在时间和空间上的术中准确性。
获取7例接受腰椎融合手术患者的腰椎荧光透视图像，进行校准，并保存到Stealth Station（FluoroNav）中。跟踪弧附着在暴露的腰椎棘突上，该棘突被指定为索引水平。利用椎板和棘突的解剖表面不规则性，在与索引水平椎骨直接相邻的三个不同椎骨上识别并注册了几个点。在整个手术过程中，每隔15分钟将探头带到每个点，并记录与原始位置的表观距离（由FluoroNav系统测量）。在手术过程中的120分钟时间内，从与索引水平相邻的三个椎骨水平收集测量数据。
在索引水平、索引+1、索引+2和索引+3水平，分别有89%、81%、92%和64%的测量值在<2 mm范围内，而分别有97%、96%、97%和91%的测量值在<3 mm范围内。在15、30、45、60、75、90、105和120分钟时，分别有96%、89%、85%、61%、85%、90%、93%和50%的测量值在<2 mm范围内，而分别有100%、93%、100%、83%、100%、90%、100%和100%的测量值在<3 mm范围内。误差毫米数倾向于随着与索引水平距离的增加（R = 0.19，P < 0.05）和手术时间的增加（R = 0.26，P < 0.01）而增加。腰椎术中虚拟荧光透视（IoVF）的校准研究证明了合理程度的准确性。腰椎IoVF过程中获得的大多数连续测量值在<3 mm的误差范围内。
我们的结果表明，在腰椎椎弓根螺钉置入过程中，使用VF是验证使用解剖和/或放射学标志进行引导的可靠方法。
