Austin Matthew S, Vaccaro Alexander R, Brislin Brian, Nachwalter Richard, Hilibrand Alan S, Albert Todd J
Department of Orthopaedic Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
Spine (Phila Pa 1976). 2002 Nov 15;27(22):2503-8. doi: 10.1097/01.BRS.0000031274.34509.1E.
A randomized comparison of conventional and image-guided technology techniques for pedicle screw placement was performed.
To evaluate the accuracy of thoracolumbosacral pedicle screw placement in simulated posterior fusion and nonfusion models via conventional and image-guided surgical techniques.
Computer-assisted image-guided technology has been promoted as a means for theoretically improving the accuracy of spinal instrumentation placement, especially when visual landmarks are obscured.
Seven embalmed cadaveric spines were cleared of all posterior soft tissue and mounted. The posterior elements of four spines were obscured so as to simulate a fusion mass using a synthetic bone cement. Three nonobscured spines also were instrumented. Pedicle screws were placed from T6 to S1 in two obscured specimens (24 screws) using a computer-assisted image-guided system, in one obscured specimen from T6 to S1 (12 screws) using a fluoroscopically assisted system, and in one obscured specimen from T6 to S1 (14 screws) using a conventional open laminoforaminotomy technique. In addition, pedicle screws were placed from T6 to S1 using a fluoroscopically assisted technique in two unobscured specimens (36 screws), and from from T6 to S1 (14 screws) via a laminoforaminotomy technique in one unobscured specimen. Pedicle violation was assessed by computed tomography scanning and direct visual inspection. The degree of screw misplacement noted visually was quantified with an electronic caliper.
Pedicle screws placed via open laminoforaminotomy resulted in a pedicle cortex breach rate of 21.43% in fused specimens and 14.29% in nonfused specimens. Screws placed in the nonfused model (two cadavers) via fluoroscopically assisted methods had pedicle cortical breaches, respectively, in 6.25% and 10% of the specimens, whereas the same method was noted to have a 8.33% violation rate in the fusion model. Finally, computed tomography-based image-guided placement through a simulated fusion mass resulted in no pedicle wall violations.
Accuracy of pedicle screw placement in the thoracolumbosacral spine is improved with the use of image-guided methods, particularly guidance by computed tomography. This is especially relevant clinically when the anatomy is obscured or altered as a result of inflammatory spondyloarthropathy (e.g., ankylosing spondylitis in which spontaneous fusions obscure surgical landmarks for pedicle access), or when used postsurgically in the setting of a posterolateral fusion.
对椎弓根螺钉置入的传统技术和影像引导技术进行了随机对照研究。
通过传统手术技术和影像引导手术技术，评估在模拟后路融合和非融合模型中胸腰段椎弓根螺钉置入的准确性。
计算机辅助影像引导技术已被推广，理论上可提高脊柱内固定置入的准确性，尤其是在视觉标志模糊不清时。
对7具防腐处理的尸体脊柱清除所有后方软组织并进行固定。对4具脊柱的后方结构进行遮挡，使用合成骨水泥模拟融合块。另外3具未遮挡的脊柱也进行内固定。在2具遮挡的标本中，使用计算机辅助影像引导系统从T6至S1置入椎弓根螺钉（24枚螺钉）；在1具遮挡的标本中，使用荧光透视辅助系统从T6至S1置入椎弓根螺钉（12枚螺钉）；在1具遮挡的标本中，使用传统开放椎板间孔切开术技术从T6至S1置入椎弓根螺钉（14枚螺钉）。此外，在2具未遮挡的标本中，使用荧光透视辅助技术从T6至S1置入椎弓根螺钉（36枚螺钉），在1具未遮挡的标本中，通过椎板间孔切开术技术从T6至S1置入椎弓根螺钉（14枚螺钉）。通过计算机断层扫描和直接肉眼检查评估椎弓根侵犯情况。用电子卡尺对肉眼观察到的螺钉误置程度进行量化。
在融合标本中，通过开放椎板间孔切开术置入的椎弓根螺钉导致椎弓根皮质破裂率为21.43%，在非融合标本中为14.29%。在非融合模型（2具尸体）中，通过荧光透视辅助方法置入的螺钉，分别有6.25%和10%的标本出现椎弓根皮质破裂，而在融合模型中该方法的破裂率为8.33%。最后，通过基于计算机断层扫描的影像引导在模拟融合块中置入螺钉未出现椎弓根壁侵犯。
使用影像引导方法，尤其是计算机断层扫描引导，可提高胸腰段椎弓根螺钉置入的准确性。在临床中，当解剖结构因炎性脊柱关节病（如强直性脊柱炎，其中自发融合使椎弓根入路的手术标志模糊）而模糊或改变时，或者在术后后外侧融合的情况下，这一点尤为重要。
