Brooks Dahari, Eskander Mark, Balsis Steve, Ordway Nat, Connolly Patrick
University of Massachusetts Memorial Medical Center, Arthritis and Total Joint Replacement Center, Worcester, MA 01605, USA.
Spine (Phila Pa 1976). 2007 Jun 1;32(13):1450-3. doi: 10.1097/BRS.0b013e318060cc88.
This is a diagnostic study in which cadavers were evaluated by imaging and dissection after pedicle screw placement.
This study was designed to evaluate the accuracy of plain radiographs and/or CT in determining pedicle instrumentation.
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.
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.
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.
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.
这是一项诊断性研究，在椎弓根螺钉置入后，通过影像学检查和解剖对尸体进行评估。
本研究旨在评估X线平片和/或CT在确定椎弓根器械置入方面的准确性。
椎弓根螺钉固定提供的一个生物力学优势是提高融合率。椎弓根螺钉置入的准确性依赖于X线片和CT。我们的目标是评估这些方法的准确性。
通过后路暴露尸体腰椎。插入钛制椎弓根螺钉。获取X线片和CT图像。然后解剖脊柱以检查螺钉位置。由一名不知情的检查者复查影像学资料。如果螺钉位于椎弓根外或有皮质穿孔的证据，则认为螺钉位置不当。
X线片、CT及两者联合检查的敏感度分别为93.9%、94%和98.7%。X线片、CT及两者联合检查的特异度分别为12.5%、36.7%和40.7%。X线片、CT及两者联合检查的阳性预测值分别为83.2%、88.1%和90.4%。X线片、CT及两者联合检查的阴性预测值分别为30.8%、55.9%和84.6%。X线片、CT及两者联合检查的准确率分别为79.4%、84.4%和90%。
对于有明显疼痛或神经功能缺损主诉的患者，联合使用X线片和CT能最佳地确定椎弓根螺钉位置。此外，通过X线片可可靠地对椎弓根螺钉固定术后患者的状况进行常规评估。椎弓根螺钉固定的生物力学优势提高了融合率，减少了维持稳定性所需的节段数。尽管椎弓根螺钉固定在临床上广泛应用，但关于其准确性的文献相对较少。本研究旨在评估X线平片和/或CT在确定椎弓根螺钉正确位置方面的准确性。
