Elfiky Tarek Anwar, Patil Nirmal Dhananjay, Luk Keith Dk, Faheem Mohamed Esam, Samartzis Dino
Spine Unit, Al-Hadra University Hospital, Alexandria, Egypt.
Department of Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India.
Asian Spine J. 2021 Apr;15(2):252-260. doi: 10.31616/asj.2019.0334. Epub 2020 Jun 12.
Retrospective radiographic study.
The hypothesis of this study was that the pedicle axis (PA) is almost perpendicular to the interlaminar line (ILL) in the sagittal plane of the thoracic vertebrae. The objective of the current study was to define the thoracic lamina-PA inclination in order to verify the right-angle concept and to estimate the safety zones for sagittal inclination during pedicle screw insertion. The authors, to the best of their knowledge, are unaware of previous similar studies.
Based on the study's observations of different spinal disorders, including deformities, it was noted that following a sagittal cranial-caudal trajectory perpendicular to the ILL and joining the two adjacent thoracic vertebrae would work well at most vertebral levels.
This was a retrospective study on the computed tomography (CT) chest scans of patients with no spinal pathologies. The ILL-PA, superior and inferior safe angles of the pedicle screw trajectories, and the exit zone of the screw perpendicular to the ILL were reviewed by two observers via three-dimensional multiplanar reconstruction mode of the Horos DICOM software (https://horosproject.org/).
The CT chest images of 30 consecutive patients (20 males and 10 females) with a mean age of 49.87±15.48 years (range, 24-74 years) were evaluated. The mean ILL-PA angle was almost orthogonal for all levels. This angle ranged between 86.21°±3.01° at D5 and 90.59°±2.72° at D10. The safety zones of the sagittal inclination of the pedicle screws were demonstrated. The results revealed that the least safe angle was when the screw was directed cranially along the middle part of the pedicle between 4.43°±0.75° at D8 and 6.94°±1.19° at D11.
The results of this study confirmed the ILL-PA angle perpendicularity in the thoracic spine at all levels. The ILL is a useful guide for pedicle screw sagittal inclination.
回顾性影像学研究。
本研究的假设是，在胸椎矢状面中，椎弓根轴线（PA）几乎垂直于椎板间线（ILL）。本研究的目的是确定胸椎椎板 - PA倾斜度，以验证直角概念，并估计椎弓根螺钉置入时矢状倾斜的安全区。据作者所知，此前尚无类似研究。
基于该研究对包括畸形在内的不同脊柱疾病的观察，注意到沿着垂直于ILL并连接两个相邻胸椎的矢状头 - 尾轨迹在大多数椎体水平效果良好。
这是一项对无脊柱病变患者的胸部计算机断层扫描（CT）进行的回顾性研究。两名观察者通过Horos DICOM软件（https://horosproject.org/）的三维多平面重建模式，对ILL - PA、椎弓根螺钉轨迹的上下安全角以及垂直于ILL的螺钉穿出区进行了评估。
对30例连续患者（20例男性和10例女性）的胸部CT图像进行了评估，这些患者的平均年龄为49.87±15.48岁（范围24 - 74岁）。所有节段的平均ILL - PA角几乎呈正交。该角度在D5节段为86.21°±3.01°，在D10节段为90.59°±2.72°。展示了椎弓根螺钉矢状倾斜的安全区。结果显示，最不安全的角度是螺钉沿椎弓根中部向头侧方向时，在D8节段为4.43°±0.75°，在D11节段为6.94°±1.19°。
本研究结果证实了胸椎各节段ILL - PA角的垂直性。ILL是椎弓根螺钉矢状倾斜的有用导向。
