[Reduction of traumatic dislocations and facet fracture-dislocations in the lower cervical spine]

Sub-Axial Cervical Facet Dislocation: A Review of Current Concepts

Cervical facet dislocation is a serious injury that carries risks of short- and long-term morbidity. The optimal management of these injuries remains controversial with the ongoing debate regarding indications and requirements for closed reduction, timing, type of surgical approach and method of fixation. This review gives an update on the relevant anatomy, classification systems for sub-axial cervical facet dislocation and an overview of the current concepts regarding their management, including surgical approaches and the choice of implants.

Subaxial Cervical Spine Injuries: WFNS Spine Committee Recommendations

To formulate specific guidelines for the recommendation of subaxial cervical spine injuries concerning classification, management, posttraumatic locked facets and vertebral artery injury. Computerized literature was searched on PubMed and google scholar database from 2009 to 2020. For classification, keywords “Sub Axial Cervical Spine Classification,” resulting in 22 articles related to subaxial cervical spine injury classification system (SLICS) system and 11 articles related to AO (Arbeitsgemeinschaft für Osteosynthesefragen, German for “Association for the Study of Internal Fixation”) Spine system. The literature search yielded 210 and 78 articles on “management of subaxial cervical spine injuries” and the role of “SLICS” and “AO Spine” respectively. Keywords “management of traumatic facet locks” were searched and closed reduction, traction, approaches and techniques were studied. “Vertebral artery injury and cervical fracture” exhibited 2,328 references from the last 15 years. The objective was to identify the appropriate diagnostic tests and optimal treatment. Up-to-date information was reviewed, and statements were produced to reach a consensus in 2 separate consensus meetings of World Federation of Neurosurgical Societies (WFNS) Spine Committee. The statements were voted and reached a positive or negative consensus using Delphi method. Based on the most relevant literature, panelists in Moscow consensus meeting conducted in May 2019 drafted the statements, and after a preliminary voting session, the consensus was identified on various statements. Another meeting was conducted at Peshawar in November 2019, where in addition to previous statements, few other statements were discussed and voted. Specific recommendations were then formulated guiding classification, management, locked facets and vertebral artery injuries. This review summarizes the WFNS Spine Committee recommendations on subaxial cervical spine injuries.

In Vitro Biomechanical Study of Epidural Pressure during the Z-shape Elevating-Pulling Reduction Technique for Cervical Unilateral Locked Facets

Objective: To analyze the mechanism of the halo vest-assisted Z-shape elevating-pulling reduction technique for cervical unilateral locked facets, and confirm the safety of the spinal cord under the epidural pressure that occurs during the reduction process. Methods: Eleven osteoligamentous whole coronal and cervical spine specimens were established as skull-neck-thorax models of cervical unilateral locked facets at the C5/6 level. The halo vest-assisted Z-shape elevating-pulling reduction technique was then applied to reduce the locked facets. The changes in the epidural pressure in five cervical positions (cervical physiological curvature, cervical lateral bending, cervical unilateral locked facets, cervical unilateral perched facets, and reduction) were measured by a pressure sensor during the reduction procedure. The models simultaneously underwent multi-angle radiographic examination and CT scanning. Results: Successful closed reduction was achieved via the halo vest-assisted Z-shape elevating-pulling reduction technique in all 11 models. The epidural pressure in the cervical unilateral locked facets position was significantly higher than that in the other four cervical positions (P < 0.005). There was no significant difference in the epidural pressures measured during cervical lateral bending, cervical unilateral perched facets, and reduction. Conclusions: Maximum epidural pressures were measured in the position of cervical unilateral locked facets. The halo vest-assisted Z-shape elevating-pulling reduction technique achieved spinal decompression without causing secondary spinal cord injury. The halo vest-assisted Z-shape elevating-pulling reduction technique is safe and effective, and has a high success rate of reduction.

Treatment of Injuries to the Subaxial Cervical Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)

STUDY DESIGN

Expert consensus.

OBJECTIVES

To establish treatment recommendations for subaxial cervical spine injuries based on current literature and the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma.

METHODS

This recommendation summarizes the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma.

RESULTS

Therapeutic goals are a stable, painless cervical spine and protection against secondary neurologic damage while retaining maximum possible motion and spinal profile. The AOSpine classification for subaxial cervical injuries is recommended. The Canadian C-Spine Rule is recommended to decide on the need for imaging. Computed tomography is the favoured modality. Conventional x-ray is preserved for cases lacking a "dangerous mechanism of injury." Magnetic resonance imaging is recommended in case of unexplained neurologic deficit, prior to closed reduction and to exclude disco-ligamentous injuries. Computed tomography angiography is recommended in high-grade facet joint injuries or in the presence of vertebra-basilar symptoms. A0-, A1- and A2-injuries are treated conservatively, but have to be monitored for progressive kyphosis. A3 injuries are operated in the majority of cases. A4- and B- and C-type injuries are treated surgically. Most injuries can be treated with anterior plate stabilization and interbody support; A4 fractures need vertebral body replacement. In certain cases, additive or pure posterior instrumentation is needed. Usually, lateral mass screws suffice. A navigation system is advised for pedicle screws from C3 to C6.

CONCLUSIONS

These recommendations provide a framework for the treatment of subaxial cervical spine Injuries. They give advice about diagnostic measures and the therapeutic strategy.

Safe management of acute cervical spine injuries

Cervical spine injuries are frequent and often caused by a blunt trauma mechanism. They can have severe consequences, with a high mortality rate and a high rate of neurological lesions.Diagnosis is a three-step process: 1) risk assessment according to the history and clinical features, guided by a clinical decision rule such as the Canadian C-Spine rule; 2) imaging if needed; 3) classification of the injury according to different classification systems in the different regions of the cervical spine.The urgency of treatment is dependent on the presence of a neurological lesion and/or instability. The treatment strategy depends on the morphological criteria as defined by the classification. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170076.

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, Internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

The second, internet-based multicenter study (MCSII) of the Spine Study Group of the German Association of Trauma Surgery (Deutsche Gesellschaft für Unfallchirurgie) is a representative patient collection of acute traumatic thoracolumbar (T1-L5) injuries. The MCSII results are an update of those obtained with the first multicenter study (MCSI) more than a decade ago. The aim of the study was to assess and bring into focus: the (1) epidemiologic data, (2) surgical and radiological outcome, and (3) 2-year follow-up (FU) results of these injuries. According to the Magerl/AO classification, there were 424 (57.8%) compression fractures (A type), 178 (24.3%) distractions injuries (B type), and 131 (17.9%) rotational injuries (C type). B and C type injuries carried a higher risk for neurological deficits, concomitant injuries, and multiple vertebral fractures. The level of injury was located at the thoracolumbar junction (T11-L2) in 67.0% of the case. 380 (51.8%) patients were operated on by posterior stabilization and instrumentation alone (POSTERIOR), 34 (4.6%) had an anterior procedure (ANTERIOR), and 319 (43.5%) patients were treated with combined posteroanterior surgery (COMBINED). 65% of patients with thoracic (T1-T10) and 57% with lumbar spinal (L3-L5) injuries were treated with a single posterior approach (POSTERIOR). 47% of the patients with thoracolumbar junction (T11-L2) injuries were either operated from posterior or with a combined posterior-anterior surgery (COMBINED) each. Short angular stable implant systems have replaced conventional non-angular stable instrumentation systems to a large extent. The posttraumatic deformity was restored best with COMBINED surgery. T-spine injuries were accompanied by a higher number and more severe neurologic deficits than TL junction or L-spine injuries. At the same time T-spine injuries showed less potential for neurologic recovery especially in paraplegic (Frankel/AISA A) patients. 5% of all patients required revision surgery for perioperative complications. Follow-up data of 558 (76.1%) patients were available and collected during a 30-month period from 1 January 2004 until 31 May 2006. On average, a posterior implant removal was carried out in a total of 382 COMBINED and POSTERIOR patients 12 months after the initial surgery. On average, the rehabilitation process required 3-4 weeks of inpatient treatment, followed by another 4 months of outpatient therapy and was significantly shorter when compared with MCSI in the mid-1990s. From the time of injury until FU, 80 (60.6%) of 132 patients with initial neurological deficits improved at least one grade on the Frankel/ASIA Scale; 8 (1.3%) patients deteriorated. A higher recovery rate was observed for incomplete neurological injuries (73%) than complete neurological injuries (44%). Different surgical approaches did not have a significant influence on the neurologic recovery until FU. Nevertheless, neurological deficits are the most important factors for the functional outcome and prognosis of TL spinal injuries. POSTERIOR patients had a better functional and subjective outcome at FU than COMBINED patients. However, the posttraumatic radiological deformity was best corrected in COMBINED patients and showed significantly less residual kyphotic deformity (biseg GDW -3.8° COMBINED vs. -6.1° POSTERIOR) at FU (p = 0.005). The sagittal spinal alignment was better maintained when using vertebral body replacement implants (cages) in comparison to iliac strut grafts. Additional anterior plate systems did not have a significant influence on the radiological FU results. In conclusion, comprehensive data of a large patient population with acute thoracolumbar spinal injuries has been obtained and analyzed with this prospective internet-based multicenter study. Thus, updated results and the clinical outcome of the current operative treatment strategies in participating German and Austrian trauma centers have been presented. Nevertheless, it was not possible to answer all remaining questions to contradictory findings of the subjective, clinical outcome and corresponding radiological findings between different surgical subgroups. Randomized-controlled long-term investigations seem mandatory and the next step in future clinical research of Spine Study Group of the German Trauma Society.

Mid- to long-term outcome of instrumented anterior cervical fusion for subaxial injuries

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.

[Anterior cervical fusion in the lower cervical spine. Locked vs nonlocked screw plate, pure cancellous bone vs tricortical strut]

Physical alterations in cervical fusions endanger healing. Experimentally we determined less stability loss in fixations using cancellous bone grafts than in those using tricortical grafts. Four hundred eighty-five Patients underwent anterior cervical fusion, for a total of 700 Segments. Patients were divided into four groups: (1) nonlocked H plate with autogenous cancellous bone, (2) nonlocked H plate with autogenous tricortical graft, (3) locked cervical plate with tricortical graft, and (4) stand-alone cage with cancellous bone. Evaluations included X-ray and random CT scan examinations. Our results suggest that anterior cervical fusions using nonlocked H screw plate systems with pure autogenous cancellous bone grafts provide the fastest (6 weeks) and most secure bone healing (P=0.00001), whereas fixations using nonlocked or locked screw plate systems and tricortical autograft require prolonged healing and develop nonunions more frequently. Complete consolidation was achieved using stand-alone cages filled with pure autogenous cancellous bone, but bony healing was delayed due to the cage. Rate of nonunions were: groups 1 and 4 0%, and groups 2 and 3 4.5% and 21%, respectively.