Contiguous-Level Unilateral Cervical Spine Facet Dislocation—A Report of a Less Discussed Subtype

AbstractUnilateral facet dislocation of subaxial cervical spine trauma is characterized by dislocation of inferior facet of superior vertebra over the superior facet of inferior vertebra. The injury is due to high-velocity trauma and associated with instability of spinal column. Such unilateral facet dislocations occurring at multiple adjacent levels for some reason are not reported or studied frequently. We have reported two cases of multiple-level dislocation of unilateral facets managed in our hospital with a review of available literature. The injury occurs as one side of the motion segment translates and rotates around an intact facet on the contralateral side. The major mechanism of injury is distractive flexion injury with axial rotation component. The injury is associated with instability secondary to loss of the discoligamentous complex. In cases with multiple-level dislocations of unilateral cervical facets, there are multiple mechanisms associated with significant neurological injury and most of them succumb at the site of injury. Only three other cases are available in English language literature. The neurological outcome is invariably poor. Multiple-level facet dislocations of subaxial cervical spine are reported sparsely in literature. We suspect that due to high-velocity nature of these injuries, most of them succumb soon after injury and not often reported. This article reports two cases of contiguous-level unilateral facet dislocation of subaxial cervical spine with associated injuries and the outcomes with review of literature.

Download Full-text

Utility of intraoperative electromyography in placing C7 pedicle screws

Journal of Neurosurgery Spine ◽

10.3171/2019.11.spine191120 ◽

2020 ◽

Vol 32 (6) ◽

pp. 891-899 ◽

Cited By ~ 1

Author(s):

Jonathan J. Rasouli ◽

Brooke T. Kennamer ◽

Frank M. Moore ◽

Alfred Steinberger ◽

Kevin C. Yao ◽

...

Keyword(s):

Cervical Spine ◽

Pedicle Screw ◽

Thoracolumbar Spine ◽

Pedicle Screws ◽

Neurological Injury ◽

Screw Placement ◽

Pedicle Screw Placement ◽

Data Set ◽

Subaxial Cervical Spine ◽

Increased Risk

OBJECTIVEThe C7 vertebral body is morphometrically unique; it represents the transition from the subaxial cervical spine to the upper thoracic spine. It has larger pedicles but relatively small lateral masses compared to other levels of the subaxial cervical spine. Although the biomechanical properties of C7 pedicle screws are superior to those of lateral mass screws, they are rarely placed due to increased risk of neurological injury. Although pedicle screw stimulation has been shown to be safe and effective in determining satisfactory screw placement in the thoracolumbar spine, there are few studies determining its utility in the cervical spine. Thus, the purpose of this study was to determine the feasibility, clinical reliability, and threshold characteristics of intraoperative evoked electromyographic (EMG) stimulation in determining satisfactory pedicle screw placement at C7.METHODSThe authors retrospectively reviewed a prospectively collected data set. All adult patients who underwent posterior cervical decompression and fusion with placement of C7 pedicle screws at the authors’ institution between January 2015 and March 2019 were identified. Demographic, clinical, neurophysiological, operative, and radiographic data were gathered. All patients underwent postoperative CT scanning, and the position of C7 pedicle screws was compared to intraoperative neurophysiological data.RESULTSFifty-one consecutive C7 pedicle screws were stimulated and recorded intraoperatively in 25 consecutive patients. Based on EMG findings, 1 patient underwent intraoperative repositioning of a C7 pedicle screw, and 1 underwent removal of a C7 pedicle screw. CT scans demonstrated ideal placement of the C7 pedicle screw in 40 of 43 instances in which EMG stimulation thresholds were > 15 mA. In the remaining 3 cases the trajectories were suboptimal but safe. When the screw stimulation thresholds were between 11 and 15 mA, 5 of 6 screws were suboptimal but safe, and in 1 instance was potentially dangerous. In instances in which the screw stimulated at thresholds ≤ 10 mA, all trajectories were potentially dangerous with neural compression.CONCLUSIONSIdeal C7 pedicle screw position strongly correlated with EMG stimulation thresholds > 15 mA. In instances, in which the screw stimulates at values between 11 and 15 mA, screw trajectory exploration is recommended. Screws with thresholds ≤ 10 mA should always be explored, and possibly repositioned or removed. In conjunction with other techniques, EMG threshold testing is a useful and safe modality in determining appropriate C7 pedicle screw placement.

Download Full-text

Surgical treatment for irreducible pediatric subaxial cervical unilateral facet dislocation: case report

Journal of Neurosurgery Pediatrics ◽

10.3171/2015.10.peds15351 ◽

2016 ◽

Vol 17 (5) ◽

pp. 607-611 ◽

Cited By ~ 2

Author(s):

Wei Qu ◽

Dingjun Hao ◽

Qining Wu ◽

Zongrang Song ◽

Jijun Liu

Keyword(s):

Case Report ◽

Cervical Spine ◽

Surgical Treatment ◽

Conservative Treatment ◽

Complete Resolution ◽

Cervical Spine Injury ◽

Spine Injury ◽

Facet Dislocation ◽

Unilateral Approach ◽

Subaxial Cervical Spine

Unilateral facet dislocation at the subaxial cervical spine (C3–7) in children younger than 8 years of age is rare. The authors describe a surgical approach for irreducible subaxial cervical unilateral facet dislocation (SCUFD) at C3–4 in a 5-year-old boy and present a literature review. A dorsal unilateral approach was applied, and a biodegradable plate was used for postreduction fixation without fusion after failed conservative treatment. There was complete resolution of symptoms and restored cervical stability. Two years after surgery, the patient had recovered range of motion in C3–4. In selected cases of cervical spine injury in young children, a biodegradable plate can maintain reduction until healing occurs, obviate the need to remove an implant, and recover the motion of the injured segment.

Download Full-text

AOSpine—Spine Trauma Classification System: The Value of Modifiers: A Narrative Review With Commentary on Evolving Descriptive Principles

Global Spine Journal ◽

10.1177/2192568219827260 ◽

2019 ◽

Vol 9 (1_suppl) ◽

pp. 77S-88S ◽

Cited By ~ 6

Author(s):

Srikanth N. Divi ◽

Gregory D. Schroeder ◽

F. Cumhur Oner ◽

Frank Kandziora ◽

Klaus J. Schnake ◽

...

Keyword(s):

Cervical Spine ◽

Classification System ◽

Injury Severity ◽

Thoracolumbar Spine ◽

Spinal Column ◽

Narrative Review ◽

Patient Specific ◽

Upper Cervical Spine ◽

Spine Trauma ◽

Subaxial Cervical Spine

Study Design: Narrative review. Objectives: To describe the current AOSpine Trauma Classification system for spinal trauma and highlight the value of patient-specific modifiers for facilitating communication and nuances in treatment. Methods: The classification for spine trauma previously developed by The AOSpine Knowledge Forum is reviewed and the importance of case modifiers in this system is discussed. Results: A successful classification system facilitates communication and agreement between physicians while also determining injury severity and provides guidance on prognosis and treatment. As each injury may be unique among different patients, the importance of considering patient-specific characteristics is highlighted in this review. In the current AOSpine Trauma Classification, the spinal column is divided into 4 regions: the upper cervical spine (C0-C2), subaxial cervical spine (C3-C7), thoracolumbar spine (T1-L5), and the sacral spine (S1-S5, including coccyx). Each region is classified according to a hierarchical system with increasing levels of injury or instability and represents the morphology of the injury, neurologic status, and clinical modifiers. Specifically, these clinical modifiers are denoted starting with M followed by a number. They describe unique conditions that may change treatment approach such as the presence of significant soft tissue damage, uncertainty about posterior tension band injury, or the presence of a critical disc herniation in a cervical bilateral facet dislocation. These characteristics are described in detail for each spinal region. Conclusions: Patient-specific modifiers in the AOSpine Trauma Classification highlight unique clinical characteristics for each injury and facilitate communication and treatment between surgeons.

Download Full-text

Regional injuries of the cervical spine: sports-related anatomical, pathophysiological, and clinical perspectives

10.1093/med/9780199533909.003.0023 ◽

2013 ◽

Author(s):

Ezequiel Gherscovici ◽

Eli Baron ◽

Alexander Vaccaro

Keyword(s):

Spinal Cord ◽

Cervical Spine ◽

Motor Vehicle ◽

Spinal Column ◽

Neurological Injury ◽

Spine Injury ◽

Sporting Events ◽

Cervical Spine Injuries ◽

Cord Injury ◽

Athletic Field

Cervical spine injuries occur infrequently on the athletic field (Dietz and Lillegard 1999). Nevertheless, sporting events have been reported as the fourth most common cause of spinal cord injury (behind motor vehicle collisions, assaults, and falls) (NSCISC 2006). The possibility of catastrophic cervical spine injury exists with involvement in sports, where it can be defined as ‘structural distortion of the cervical spinal column associated with actual or potential damage to the spinal cord’. This may result in irreversible neurological injury to the athlete (...

Download Full-text

SUBAXIAL CERVICAL FRACTURE: APPLICATION AND CORRELATION OF AO AND SLIC

Coluna/Columna ◽

10.1590/s1808-185120151403114135 ◽

2015 ◽

Vol 14 (3) ◽

pp. 218-222

Author(s):

Allan Hiroshi de Araujo Ono ◽

Ivan Dias da Rocha ◽

Alexandre Fogaça Cristante ◽

Raphael Martus Marcon ◽

Reginaldo Perilo Oliveira ◽

...

Keyword(s):

Cervical Spine ◽

Pearson Correlation ◽

Statistical Significance ◽

Neurological Status ◽

Statistical Correlation ◽

Neurological Injury ◽

Spine Injury ◽

Cervical Fracture ◽

Subaxial Cervical Spine ◽

Duration Of Surgery

Objective:To evaluate the AO/Magerl classification and the SLIC (Subaxial Cervical Spine Injury Classification), used in the cervical spine fractures and assess whether they are correlated to the neurological severity of patients, the choice of approach to be used, de duration of surgery an between themselves.Method:Retrospective analysis of medical records and radiological image files of 77 patients surgically treated of subaxial cervical fracture or dislocation from August 2010 to September 2012.Results:The SLIC classification showed a strong correlation with neurological deficit and Pearson correlation value of -0.600. The AO classification was not correlated with the Frankel scale and the value of Pearson was 0.06 with a statistical significance of 0.682 (p<0.05), that is, unable to determine or suggest the severity of the deficit. When compared to each other the two classifications showed statistical correlation and the value of Pearson was 0.282 with a significance value of 0.022 (p<0.05).Conclusion:Among the most used classifications, the SLIC has been able to statistically define the need for surgical treatment and the severity of the neurological status, but was unable to predict the approach or the time of the surgery; the classification AO failed to predict the severity of neurological injury, surgical time, and did not help to choose the approach, just being a morphological classification.

Download Full-text

Anatomy and biomechanics of the craniovertebral junction

Neurosurgical FOCUS ◽

10.3171/2015.1.focus14807 ◽

2015 ◽

Vol 38 (4) ◽

pp. E2 ◽

Cited By ~ 39

Author(s):

Alejandro J. Lopez ◽

Justin K. Scheer ◽

Kayla E. Leibl ◽

Zachary A. Smith ◽

Brian J. Dlouhy ◽

...

Keyword(s):

Cervical Spine ◽

Large Degree ◽

Axial Rotation ◽

Craniovertebral Junction ◽

Anatomical Structures ◽

Complex Combination ◽

Subaxial Cervical Spine ◽

Flexion Extension ◽

Fixation Techniques ◽

Vascular Structures

The craniovertebral junction (CVJ) has unique anatomical structures that separate it from the subaxial cervical spine. In addition to housing vital neural and vascular structures, the majority of cranial flexion, extension, and axial rotation is accomplished at the CVJ. A complex combination of osseous and ligamentous supports allow for stability despite a large degree of motion. An understanding of anatomy and biomechanics is essential to effectively evaluate and address the various pathological processes that may affect this region. Therefore, the authors present an up-to-date narrative review of CVJ anatomy, normal and pathological biomechanics, and fixation techniques.

Download Full-text

Anterior-Alone Surgical Treatment for Subaxial Cervical Spine Facet Dislocation: A Systematic Review

Global Spine Journal ◽

10.1177/2192568220907574 ◽

2020 ◽

pp. 219256822090757

Author(s):

Wendy Lee ◽

Chung Chek Wong

Keyword(s):

Systematic Review ◽

Cervical Spine ◽

Open Reduction ◽

Meta Analysis ◽

Fracture Dislocation ◽

Facet Dislocation ◽

Subaxial Cervical Spine ◽

Mesh Terms ◽

Facet Fracture ◽

Cervical Facet

Study Design: Systematic review. Objective: Anterior-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. Methods: A 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. Results: Nonunion 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. Conclusions: This 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.

Download Full-text