Anatomical considerations for cervical pedicle screw insertion: the use of multiplanar computerized tomography reconstruction measurements

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The purpose of this study was to evaluate the linear and angular parameters of the vertebral body (VB) required for cervical pedicle screw (CPS) insertion by using multiplanar computerized tomography (CT) reconstructions.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Three hundred fifteen vertebrae from C-3 to C-7 in 63 patients were studied. Pedicle dimensions such as pedicle transverse angle (PTA), pedicle sagittal angle (PSA), and pedicle outer width (POW) were measured on axial CT reconstructions, as were linear parameters including the lateral mass thickness (LMT), the anteroposterior (AP) and mediolateral distances between spinal canal and transverse foramen, and spinal canal longitudinal and transverse diameter. In addition, the correlations between PTA and other parameters were calculated using univariate linear regression analysis.</jats:p> <jats:p>The overall mean LMT ranged from 10.7 to 12.6 mm. The smallest mean AP spinal canal–transverse foramen distance was found at C-7 (1.1 mm),whereas the largest mean distance was at C-4 (3.1 mm). The smallest mean mediolateral spinal canal–transverse foramen distance was found at C-4 (1.2 mm), whereas the largest mean distance was at C-7 (4.7 mm). There were significant intergroup differences between male and female patients except for PTA and spinal canal longitudinal diameter. The PTA had a direct linear correlation with AP and mediolateral spinal canal–transverse foramen distances. The largest Pearson coefficient was 0.71 between the PTA and AP spinal canal–transverse foramen distance and the inverse one was −0.73 between the PTA and mediolateral spinal canal–transverse foramen distance.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Analysis of the data obtained in this study suggests that not only pedicle dimensions but also linear and angular parameters of the VB can be useful data when inserting a CPS.</jats:p></jats:sec>

Surgical safety of cervical pedicle screw placement with computer navigation system

“…Karaikovic et al investigated cervical pedicle morphology using human cadaver specimens via manual and computed tomography measurements and suggested that there were anatomical limitations associated with the use of the pedicle screw in the cervical spine [22, 23]. Chazono et al evaluated the linear and angular parameters of the cervical spine as well as pedicle dimensions required for safe CPS placement using multiplanar CT reconstruction [24]. They reported that the overall mean pedicle transverse angle (PTA) ranged from 33.6 to 50.2° and that the smallest mean PTA was found at C7 in males (33.4°) and in females (34.1°); the largest mean PTA was found at C4 in males (50.4°) and in females (49.6°) followed by C5, C3, and C6.…”

The feasibility of transpedicular screw fixation of the subaxial cervical spine in the Arab population: a computed tomography-based morphometric study

“…This diameter allows at least 0.5 mm bony bridge medially and laterally in order to avoid pedicle violation which can result in neurovascular complications [1, 12, 16, 22, 23]. Based on data from previous reports and our current study, the OPW is considered to be the most important parameter in assessing the feasibility of the TPSF technique [1, 2, 9, 12, 24, 25]. This is because the OPH is larger than the width.…”

“…In addition to these measurements, the interpedicular distance (IPD) was also measured. The pedicle sagittal angle was not measured in our current study because of the variation in the technique of measuring this angle among previous investigators making it an unreliable measure [9–12]. …”

The Subaxial Cervical Pedicle Screw for Cervical Spine Diseases: The Review of Technical Developments and Complication Avoidance

“…Anatomical considerations for the safety and accuracy of the cervical pedicle screw For accurate and safe subaxial CPS placement, surgeons should understand the detailed threedimensional (3D) morphology of the pedicle. With regard to reports on the morphology of the cervical pedicle, [17][18][19][20][21][22][23] the measured parameters including pedicle transverse angle (PTA) and pedicle outer width (POW) are indicated in Fig. 2A.…”

“…The smallest mean POW of 4.5 mm was obtained at C3, with gradual increases in the mean value caudally from C3 to C7. 17,22) Karaikovic et al 24) reported that if the POW is sufficiently large, a canal of adequate size can be made with an appropriate tap, regardless of the pedicle inner width. Abumi et al 25) used 3.5-4.5-mm diameter screws and reported that screw insertion was difficult or impossible in cases with a POW of <4 mm; whereas, Park et al 26) used 3.5-4.5-mm diameter pedicle screws in cases with a POW of >3 mm on axial computed tomography (CT) scan.…”