腰椎弓根螺钉放置的影像学评估
Imaging Assessment of Lumbar Pedicle Screw Placement: Sensitivity and Specificity of Plain Radiographs and Computer Axial Tomography.
Dahari Brooks, MD; Mark Eskander, MD; Steve Balsis, PhD; Nat Ordway, MS, PE; Patrick Connolly, MD
腰椎弓根螺钉放置的影像学评估：平片和轴向CT的敏感性和特异性
Study Design. This is a diagnostic study in which cadavers were evaluated by imaging and dissection after pedicle screw placement.
研究设计：诊断学研究，在尸体上打入椎弓根螺钉后，利用影像学和解剖切开进行评估。
Objective. This study was designed to evaluate the accuracy of plain radiographs and/or CT in determining pedicle instrumentation.
目的：评估平片和/或CT在评价椎弓根操作方面的准确性。
Summary of Background Data. One biomechanical advantage provided by pedicle screws fixation is improved fusion rates. The accuracy of pedicle screw placement has relied on radiograph and CT. Our goal is to evaluate the accuracy of these methods.
背景：椎弓根螺钉固定的一项生物力学优势是增加融合率。椎弓根螺钉放置的准确性依赖于X片和CT。我们的目的是评价这些手段的准确性。
Methods. Cadaveric lumbar spines were exposed by a posterior approach. Titanium pedicle screws were inserted. Radiographs and CTs were obtained. The spines were then dissected to examine screw location. A blinded examiner reviewed the imaging. Screws were considered misaligned if they were extrapedicular or had evidence of cortical perforation.
方法：从后方暴露尸体腰椎，打入钛制椎弓根螺钉，然后摄X片和CT。之后再切开腰椎检查螺钉的位置。由一名未被告知结果的检查者读片。如果螺钉在椎弓根外或穿破皮质，便可以认为不准。
Results. The sensitivity of radiographs, CT, and combined is 93.9%, 94%, and 98.7%, respectively. The specificity of radiograph, CT, and combined is 12.5%, 36.7%, and 40.7%, respectively. The positive predictive value for radiograph, CT, and combined is 83.2%, 88.1%, and 90.4%, respectively. The negative predictive value for radiograph, CT, and combined is 30.8%, 55.9%, and 84.6%, respectively. The accuracy of radiograph, CT, and combined is equal to 79.4%, 84.4%, and 90%, respectively.
结果：X片、CT以及二者联用的敏感度分别为93.9%、94%和98.7%；特异度分别为12.5%、36.7%和40.7%；阳性预测值分别为83.2%、88.1%和90.4%；阴性预测值为30.8%、55.9%和84.6%。X片、CT以及二者联用的准确度分别等于79.4%、84.4%和90%。
Conclusion. Patients who present with significant complaints of pain or neurologic deficits, optimal determination of pedicle screw positions is with the combination of radiographs and CT. Furthermore, routine evaluation of patients’ status post pedicle screw fixation can be reliable obtained with radiographs. The biomechanical advantage of pedicle screw fixation has improved fusion rates and diminished the number of levels required for stability. Despite the widespread clinical use of pedicle screw fixation, there is relatively little literature concerning accuracy. This study was designed to evaluate the
accuracy of plain radiographs and/or CT in determining the proper position of pedicle screws.
结论：对于主诉为疼痛或神经功能障碍的患者，X片和CT联用是评价椎弓根螺钉位置的最佳方法。此外，X片可以作为评价椎弓根螺钉固定术后患者情况的可靠的常规手段。椎弓根螺钉的生物力学优势使融合率增加，并使稳定所需的固定节段减少。尽管椎弓根螺钉固定已在临床上得到了广泛使用，但关注于准确性的文献相对来说还比较少。本研究评价了平片和/或CT在评价椎弓根螺钉正确位置上的准确性。
[ 本帖最后由 daike_ren 于 2008-6-23 19:19 编辑 ]
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