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Anatomic Study of Anterior Transdiscal Axial Screw Fixation for Subaxial Cervical Spine Injuries.

Ji W, Zheng M, Qu D, Zou L, Chen Y, Chen J, Zhu Q - Medicine (Baltimore) (2016)

Bottom Line: The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth).Except the axial screw length, increase in all the measurements was seen with level up to C5-C6 segment.All screws were placed accurately.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.

ABSTRACT
Anterior transdiscal axial screw (ATAS) fixation is an alternative or supplement to the plate and screw constructs for the upper cervical spine injury. However, no existing literatures clarified the anatomic feasibility of this technique for subaxial cervical spine. Therefore, the objective of this study was to evaluate the anatomical feasibility and to establish guidelines for the use of the ATAS fixation for the subaxial cervical spine injury.Fifty normal cervical spines had radiographs to determine the proposed screw trajectory (the screw length and insertion angle) and the interbody graft-related parameters (the disc height and depth, and the distance between anterior vertebral margin and the screw) for all levels of the subaxial cervical spine. Following screw insertion in 8 preserved human cadaver specimens, surgical simulation and dissection verified the feasibility and safety of the ATAS fixation.Radiographic measurements showed the mean axial screw length and cephalic incline angle of all levels were 41.2 mm and 25.2°, respectively. The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth). Except the axial screw length, increase in all the measurements was seen with level up to C5-C6 segment. Simulated procedure in the preserved specimens demonstrated that ATAS fixation could be successfully performed at C2-C3, C3-C4, C4-C5, and C5-C6 levels, but impossible at C6-C7 due to the obstacle of the sternum. All screws were placed accurately. None of the screws penetrated into the spinal canal and caused fractures determined by dissecting the specimens.The anterior transdiscal axial screw fixation, as an alternative or supplementary instrumentation for subaxial cervical spine injuries, is feasible and safe with meticulous surgical planning.

No MeSH data available.


Related in: MedlinePlus

Photograph showing the system of tools to facilitate insertion of screw.
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Figure 3: Photograph showing the system of tools to facilitate insertion of screw.

Mentions: Eight preserved human cadaver specimens (5 males/3 females) of East Asian ancestry with unknown age were obtained from the Department of Anatomy. The specimen was confirmed by x-ray to have a normal cervical spine. The cadaver heads were secured with pins in a head-holder (Figure 2), avoiding flexion-extension and rotation. The tools necessary to facilitate insertion of a screw include the following equipment seen in Figure 3.


Anatomic Study of Anterior Transdiscal Axial Screw Fixation for Subaxial Cervical Spine Injuries.

Ji W, Zheng M, Qu D, Zou L, Chen Y, Chen J, Zhu Q - Medicine (Baltimore) (2016)

Photograph showing the system of tools to facilitate insertion of screw.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4979770&req=5

Figure 3: Photograph showing the system of tools to facilitate insertion of screw.
Mentions: Eight preserved human cadaver specimens (5 males/3 females) of East Asian ancestry with unknown age were obtained from the Department of Anatomy. The specimen was confirmed by x-ray to have a normal cervical spine. The cadaver heads were secured with pins in a head-holder (Figure 2), avoiding flexion-extension and rotation. The tools necessary to facilitate insertion of a screw include the following equipment seen in Figure 3.

Bottom Line: The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth).Except the axial screw length, increase in all the measurements was seen with level up to C5-C6 segment.All screws were placed accurately.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.

ABSTRACT
Anterior transdiscal axial screw (ATAS) fixation is an alternative or supplement to the plate and screw constructs for the upper cervical spine injury. However, no existing literatures clarified the anatomic feasibility of this technique for subaxial cervical spine. Therefore, the objective of this study was to evaluate the anatomical feasibility and to establish guidelines for the use of the ATAS fixation for the subaxial cervical spine injury.Fifty normal cervical spines had radiographs to determine the proposed screw trajectory (the screw length and insertion angle) and the interbody graft-related parameters (the disc height and depth, and the distance between anterior vertebral margin and the screw) for all levels of the subaxial cervical spine. Following screw insertion in 8 preserved human cadaver specimens, surgical simulation and dissection verified the feasibility and safety of the ATAS fixation.Radiographic measurements showed the mean axial screw length and cephalic incline angle of all levels were 41.2 mm and 25.2°, respectively. The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth). Except the axial screw length, increase in all the measurements was seen with level up to C5-C6 segment. Simulated procedure in the preserved specimens demonstrated that ATAS fixation could be successfully performed at C2-C3, C3-C4, C4-C5, and C5-C6 levels, but impossible at C6-C7 due to the obstacle of the sternum. All screws were placed accurately. None of the screws penetrated into the spinal canal and caused fractures determined by dissecting the specimens.The anterior transdiscal axial screw fixation, as an alternative or supplementary instrumentation for subaxial cervical spine injuries, is feasible and safe with meticulous surgical planning.

No MeSH data available.


Related in: MedlinePlus