Posterior Fusion for the Subaxial Cervical Spine: A Review of the Major Techniques.
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ABSTRACT:
SUBMITTER: Mikhail CM
PROVIDER: S-EPMC7253542 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Background Posterior facetectomy or lateral mass resection is often used during cervical dumbbell tumor resection, jeopardizing the stability of cervical spine. The space after resection of one or more lateral masses, if left unfilled might hamper bone fusion and structural support.Purpose There were the aims to obtain the relevant morphometry of the lateral mass of the subaxial cervical spine (C3-C7) and to design a lateral mass prosthesis for the posterior reconstruction of the cervical spine.Methods The computed tomography (CT) scans of healthy volunteers were obtained. RadiAnt DICOM Viewer software (Version 2020.1, Medixant, Poland) was used to measure the parameters of lateral mass, such as height, anteroposterior dimension (APD), mediolateral dimension (MLD), and facet joint angle. According to the parameters, a series of cervical lateral mass prostheses were designed. Cadaver experiment was conducted to demonstrate its feasibility.Results Twenty-three volunteers with an average age of 30.1 ± 7.1 years were enrolled in this study. The height of the lateral mass was 14.1 mm on average. The facet joint angle, APD, and MLD of the lateral mass averaged 40.1 degrees, 11.2 mm, and 12.2 mm, respectively. With these key data, a lateral mass prosthesis consisting of a column and a posterior fixation plate was designed. The column has a 4.0-mm radius, 41-degree surface angle, and adjustable height of 13, 15, or 17 mm. In the cadaver experiment, the column could function as a supporting structure between adjacent facets, and it would not violate the exiting nerve root or the vertebral artery.Conclusion This study provided a detailed morphology of the lateral mass of the subaxial cervical spine. A series of subaxial cervical lateral mass prostheses were designed awaiting further clinical application.
| S-EPMC10226812 | biostudies-literature
Project description:Introduction The cervical spine is a highly mobile segment of the spinal column, liable to a variety of diseases and susceptible to trauma. It is a complex region where many vital structures lie in close proximity. Lateral mass screw fixation has become the method of choice in stabilizing subaxial cervical spine among other posterior cervical fixation techniques whenever the posterior elements are absent or compromised. Objective This study examined cervical specimens of cadavers and cervical computed tomography (CT) scans to minimize as much as possible complications of cervical lateral mass screw placement such as vertebral artery or nerve root injuries, facet joint violations, or inadequate placement. Methods Forty normal cervical CT scans, obtained from the emergency unit as part of the trauma workup, were included in this study plus 10 cervical cadaveric specimens obtained from the Alexandria Neuro-anatomy laboratory. There were three fixed parameters for screw insertion in this study. First, the point of screw insertion was the midpoint of the lateral mass; it was the crossing point between the sagittal and axial planes of the posterior cortex of the lateral mass. Second, the direction of the screw in the craniocaudal plane was 30 degrees cranially to avoid facet joint penetration. Third, the exit point of the screw was located on the ventral cortex of the lateral mass just lateral to the root of the transverse process in the midaxial cut of each lateral mass, to make a sound bicortical fixation without injuring the vertebral artery or the nerve root. The selected screw trajectory in this study was the line drawn between the inlet and exit points. The depth and width of the lateral mass of the cervical vertebrae from C3 to C7 were measured as well as the angle of screw trajectory from the sagittal plane. All these measures were applied on the cadaveric specimens to make sure that no injury to the vertebral artery, nerve root, or facet joint occurred. Results As regards the collected measurements of the lateral mass of all subaxial cervical vertebrae, the study revealed that the average depth of the lateral mass was 12.83 ± 1.28 mm. The average width of the lateral mass was 11.92 ± 0.96 mm. The average divergent angle of bicortical screw insertion without injury to the vertebral artery or the nerve root was 19.51 ± 1.83 degrees. As regard the cadaveric specimens, based on all the collected measurements taken from the CT scans, there was no reported injury to the vertebral arteries or nerve roots or penetration to the facet joints. Conclusion Lateral mass fixation can be applied easily and safely for all levels of subaxial cervical spine from C3 to C6 with the following parameters: (1) the point of entry is the midpoint of the lateral mass; (2) the screw trajectory is directed 30 degrees cranially and 20 degrees laterally; (3) the screw length is 13 to 15 mm.
| S-EPMC3864406 | biostudies-other
Project description:Study designGlobal cross-sectional survey.ObjectiveThe aim of this study was to validate the AO Spine Subaxial Cervical Spine Injury Classification by examining the perceived injury severity by surgeon across AO geographical regions and practice experience.Summary of background dataPrevious subaxial cervical spine injury classifications have been limited by subpar interobserver reliability and clinical applicability. In an attempt to create a universally validated scheme with prognostic value, AO Spine established a subaxial cervical spine injury classification involving four elements: injury morphology, facet injury involvement, neurologic status, and case-specific modifiers.MethodsA survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. Respondents graded the severity of each variable of the classification system on a scale from zero (low severity) to 100 (high severity). Primary outcome was to assess differences in perceived injury severity for each injury type over geographic regions and level of practice experience.ResultsA total of 189 responses were received. Overall, the classification system exhibited a hierarchical progression in subtype injury severity scores. Only three subtypes showed a significant difference in injury severity score among geographic regions: F3 (floating lateral mass fracture, P = 0.04), N3 (incomplete spinal cord injury, P = 0.03), and M2 (critical disk herniation, P = 0.04). When stratified by surgeon experience, pairwise comparison showed only two morphological subtypes, B1 (bony posterior tension band injury, P = 0.02) and F2 (unstable facet fracture, P = 0.03), and one neurologic subtype (N3, P = 0.02) exhibited a significant difference in injury severity score.ConclusionThe AO Spine Subaxial Cervical Spine Injury Classification System has shown to be reliable and suitable for proper patient management. The study shows this classification is substantially generalizable by geographic region and surgeon experience, and provides a consistent method of communication among physicians while covering the majority of subaxial cervical spine traumatic injuries.Level of Evidence: 4.
| S-EPMC8057527 | biostudies-literature
Project description:Study designSystematic review.ObjectiveAnterior-alone surgery has gained wider reception for subaxial cervical spine facets dislocation. Questions remain on its efficacy and safety as a stand-alone entity within the contexts of concurrent facet fractures, unilateral versus bilateral dislocations, anterior open reduction, and old dislocation.MethodsA systematic review was performed with search strategy using translatable MESH terms across MEDLINE, EMBASE, VHL Regional Portal, and CENTRAL databases on patients with subaxial cervical dislocation intervened via anterior-alone approach. Two reviewers independently screened for eligible studies. PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) flow chart was adhered to. Nine retrospective studies were included. Narrative synthesis was performed to determine primary outcomes on spinal fusion and revisions and secondary outcomes on new occurrence or deterioration of neurology and infection rate.ResultsNonunion was not encountered across all contexts. A total of 0.86% of unilateral facet dislocation (1 out of 116) with inadequate reduction due to facet fragments between the facet joints removed its malpositioned plate following fusion. No new neurological deficit was observed. Cases that underwent anterior open reduction did not encounter failure that require subsequent posterior reduction surgery. One study (N = 52) on old dislocation incorporated partial corpectomy in their approach and limited anterior-alone approach to cases with persistent instability.ConclusionsThis systematic review supports the efficacy and success of anterior reduction, fusion, and instrumentation for cervical facet fracture dislocation. It is safe from a neurological standpoint. Revision rate due to concurrent facet fracture is low. Certain patients may require posteriorly based surgery or in specific cases combined anterior and posterior procedures.
| S-EPMC7882821 | biostudies-literature
Project description:Study Design Literature review. Objective To discuss the evaluation and management of subaxial cervical spine trauma (C3-7). Methods A literature review of the main imaging modalities, classification systems, and nonsurgical and surgical treatment performed. Results Computed tomography and reconstructions allow for accurate radiologic identification of subaxial cervical spine trauma in most cases. Magnetic resonance imaging can be utilized to evaluate the stabilizing discoligamentous complex, the nerves, and the spinal cord. The Subaxial Injury Classification (SLIC) is a new system that aids in injury classification and helps guide the decision-making process of conservative versus surgical treatment. Though promising, the SLIC system requires further validation. When the decision for surgical treatment is made, early decompression (less than 24 hours) has been associated with better neurologic recovery. Surgical treatment should be individualized based on the injury characteristics and surgeon's preferences. Conclusions The current state of subaxial cervical spine trauma is one of great progress. However, many questions remain unanswered. We need to continue to account for the individual patient, surgeon, and hospital circumstances that effect decision making and care.
| S-EPMC3908983 | biostudies-other
Project description: Not available
| S-EPMC7571631 | biostudies-literature
Project description:The purpose of this article is to introduce and analyze the feasibility of simultaneously combined anterior-posterior approaches for subaxial cervical circumferential reconstruction in sitting position. A retrospective case review was performed for above surgery procedure. A 79-year-old man was confirmed subaxial cervical fracture and dislocation with facet locked by radiological examination, and the involved levels were C5-6. According to American Spinal Injury Association (ASIA) classification, the impairment scale was grade B. And the Subaxial Cervical Spine Injury and Severity Score (SLIC) were 9. The patient was restricted in sitting position with traction on a halo in extension to immobilize the head during the operation. A posterior laminectomy and pedicle screws insertion to the involved cervical spine was performed firstly. And then the anterior discectomy and strut graft were accomplished through an anterior cervical approach. The final fixation was finished by clamping the strut graft with pedicle screw system. Total blood loss was 600 ml and the total operating time was 150 min. The patient was followed up for 6 months. The symptom of neck pain improved distinctly and no evidence about implant failure was noted. Neurological status improvement was confirmed and the ASIA scale was improved to grade C. We believed that the simultaneously combined anterior-posterior approach in sitting position was safe and more advantageous for appropriate cases.
| S-EPMC6583720 | biostudies-literature
Project description:The management of patients with subaxial cervical injuries lacks consensus, particularly in regard to the decision which surgical approach or combination of approaches to use and which approach yields the best clinical outcome in the distinct injury. The trauma literature is replete with reports of surgical techniques, complications and gross outcome assessment in heterogeneous samples. However, data on functional and clinical outcome using validated outcome measures are scanty. Therefore, the authors performed a study on plated anterior cervical decompression and fusion for unstable subaxial injuries with focus on clinical outcome. For the purpose of a strongly homogenous subgroup of patients with subaxial injuries without spinal cord injuries, robust criteria were applied that were fulfilled by 28 patients out of an original series of 131 subaxial injuries. Twenty-six patients subjected to 1- and 2-level fusions without having spinal cord injury could be surveyed after a mean of 5.5 years (range 16-128 months). The cervical spine injury severity score averaged 9.6. Cross-sectional outcome assessment included validated outcome measures (Neck pain disability index, Cervical Spine Outcome Questionnaire, SF-36), the investigation of construct failure and successful surgical outcome were defined by strict criteria, the reconstruction and maintenance of local and total cervical lordosis, adjacent-segment degeneration and intervertebral motion, and the fusion-rate using an interobserver assessment. Self-rated clinical outcome was excellent or good in 81% of patients and moderate or poor in 19% that corresponded to the results of the validated outcome measures. Results of the NPDI averaged 12.4 +/- 12.7% (0-40). With the SF-36 mean physical and mental component summary scores were 47.0 +/- 9.8 (18.2-59.3) and 52.2 +/- 12.4 (14.6-75.3), respectively. Using merely non-constrained plates, construct failure was observed in 31% of cases and loss of local lordosis, expressed as a mean injury angle of 14 degrees, postoperative angle of -5.5 degrees and follow-up angle of -1 degree, was significant. However, total cervical lordosis was within the limits of normalcy (-24.3 degrees +/- 13.3) and fusion-rate was 88.5%. The progression of adjacent-level degeneration was shown to be significantly influenced by a decreased plate-to-disc-distance. Adjacent-level intervertebral motion was not altered due to the adjacent fusion, but reduced in the presence of advanced adjacent-level degeneration. Patients were more likely to maintain a high satisfaction level if they succeeded to maintain segmental lordosis (<0 degree), had a solid fusion, an increased plate-to-disc distance, and if they were judged to have a successful surgical outcome that included the absence of construct failure and reconstruction of lordosis within +/-1 SD of normalcy. Using validated outcome vehicles the interdependencies between radiographical, functional and clinical outcome parameters could be substantiated with statistically significant correlations. The use of validated outcome vehicles in a subgroup of patients with plated anterior cervical fusions for subaxial injuries is recommended. With future studies, it enables objective comparison of surgical techniques and related radiographical, functional and clinical outcome.
| S-EPMC3233996 | biostudies-literature
Project description: Not available
| S-EPMC7571633 | biostudies-literature
Project description: Not available
| S-EPMC3940790 | biostudies-literature