An analysis of the anatomic features of the cervical spine using computed tomography to select safer screw insertion techniques

Nishinome, Masahiro; Iizuka, Haku; Iizuka, Yoichi; Takagishi, Kenji

doi:10.1007/s00586-013-2883-5

Cited by 13 publications

(10 citation statements)

References 21 publications

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“…In a further investigation of CT scans of 122 cervical spines, Onibokun et al [8] report a mean pedicle transverse angle of approximately 44° from C3 to C6 and 37.8° at C7. Similar values of pedicle transverse angles are reported by Nishinome et al [9] based on an investigation of 50 CT scans of cervical spines (C3 to C6). They report a pedicle transverse angle of 37.1°-45.4°.…”

Section: Discussionsupporting

confidence: 87%

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Insertion Angle of Pedicle Screws in the Subaxial Cervical Spine: The Analysis of Computed Tomography-Navigated Insertion of Pedicle Screws

et al. 2020

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Four orthopedic spine surgeons measured the radiological parameters of pedicle screws in the cervical spine using a postoperative computed tomography (CT) scan. Purpose: This study analyzed the insertion angle of CT-navigated insertion of pedicle screws in the subaxial cervical spine and classified them according to their position. Overview of Literature: Overall, a pedicle transverse angle of 33.6°-50.2° with a mean angle of 45° relative to the midline has been reported in the literature. Methods: The insertion angles of 87 pedicle screws inserted using CT-based navigation in the subaxial cervical spine were measured in the postoperative CT. The screw positioning was determined according to the modified Gertzbein and Robbins classification. Results: Total 89.3% (n=78) of the pedicle screws inserted using CT-based navigation showed good placement. The mean insertion angle of the pedicle screws that showed good positioning was 29.9°±9.9°. The pedicle screws showing bad positioning had a mean insertion angle of 26.8°±10.5° (p=0.157). The interobserver reliability showed a reliable measurement intraclass correlation coefficient: 0.994 (95% confidence interval, 0.992-0.996). Conclusions: The present results show that the insertion angle of the pedicle screws in the subaxial cervical spine was smaller than the actual pedicle transverse angle, as per the literature. One reason for this discrepancy could be that the navigation systems allow the insertion of cervical pedicle screws with a lower convergence.

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Section: Discussionsupporting

confidence: 87%

“…Further investigations have identified the transverse angle for safe insertion of a pedicle screw in the subaxial cervical spine. Overall, a pedicle transverse angle of 33.6°-50.2° with a mean angle of 45° relative to the midline has been reported in the literature [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Insertion Angle of Pedicle Screws in the Subaxial Cervical Spine: The Analysis of Computed Tomography-Navigated Insertion of Pedicle Screws

et al. 2020

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“…Multiple cadaveric studies 2,6-9,11 and CT-based studies 9,10,[12][13][14][15][16][17][18][19][20][21] have been done in the past to help determine subaxial cervical spine morphology and geometry in order to generate data to help spine surgeons in reducing complications associated with CPS placement. Panjabi et al 11 in 1991 were the first to study cervical spine 3-dimensional morphology in cadavers.…”

Section: Discussionmentioning

confidence: 99%

Computerized Tomography–Based Morphometric Analysis of Subaxial Cervical Spine Pedicle in Asymptomatic Indian Population

et al. 2018

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Background: The purpose of this study was to analyze morphometry of the subaxial cervical spine pedicles in an Indian population based on computed tomography (CT), and thus assess the safety and feasibility of cervical pedicle screw in the subaxial cervical spine. Methods: CT scans of 500 subaxial cervical spine vertebrae were analyzed from 100 patients presenting to our institution and undergoing cervical spine CT scan for an unrelated cause as part of ATLS protocol. Pedicle width (PW), pedicle axis length (PAL), pedicle transverse angulation (PTA), and lateral pedicle distance (LPD) were calculated on axial CT scans, and pedicle height (PH), pedicle length (PL), superior pedicle distance (SPD), and pedicle sagittal angulation (PSA) were calculated on sagittal CT scans.

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“…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.…”

Section: Selection Of Reference Articlesmentioning

confidence: 99%

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

Jung

Lee

et al. 2020

Neurol. Med. Chir.(Tokyo)

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This study aimed to review information on the subaxial cervical pedicle screw (CPS) including recent anatomical considerations, entry points, placement techniques, accuracy, learning curve, and complications. Relevant literatures were reviewed, and the authors' experiences were summarized. The CPS is used for reconstruction of unstable cervical spine and achieves superior biomechanical stability compared to other fixation techniques. Various insertion and guidance techniques are established, among which, lateral fluoroscopy-assisted placement is the most common and cost-effective technique. Generally, placement under imaging guidance is more accurate than other techniques, and a threedimensional template allows optimal trajectory for each pedicle regardless of intraoperative changes in spinal alignment. The free-hand technique using a curved pedicle probe without a funnel-like hole increases screw stability and reduces operation time, radiation exposure, and soft tissue injury. Compared to conventional lateral fluoroscopy-assisted placement, free-hand CPS placement by trained surgeons achieves superior accuracy comparable to that of image-guided navigation; in general, 30 training cases are sufficient for learning a safe and accurate technique for CPS placement. The complications of subaxial CPS are classified into three categories: complications due to screw misplacement, complications without screw misplacement, and others. Inexperienced surgeons may benefit from advanced techniques; however, the accuracy of CPS ultimately depends on the surgeon's experience. Inexperienced surgeons should master the placement of the thoracolumbar pedicle screw in real practice and practice CPS insertion using cadavers. During the initial phase of the learning curve, careful preparation of surgery, reiterated identification, patterned safety steps, and supervision of the expert are necessary.

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An analysis of the anatomic features of the cervical spine using computed tomography to select safer screw insertion techniques

Abstract: We suggest that in cases in which pedicle screw insertion is difficult, lateral mass screws (LMS) can be inserted safely and longer sizes can be selected. In contrast, in cases in which LMS insertion is difficult, the insertion of pedicle screws can be performed relatively easy.

Cited by 13 publications

References 21 publications

Insertion Angle of Pedicle Screws in the Subaxial Cervical Spine: The Analysis of Computed Tomography-Navigated Insertion of Pedicle Screws

Insertion Angle of Pedicle Screws in the Subaxial Cervical Spine: The Analysis of Computed Tomography-Navigated Insertion of Pedicle Screws

Computerized Tomography–Based Morphometric Analysis of Subaxial Cervical Spine Pedicle in Asymptomatic Indian Population

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

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