Traumatic and neoplastic instability of the cervical spine

Determining the stability of the cervical spine is paramount to the successful management of patients with cervical spine trauma or neoplastic disease. While this article will discuss both traumatic instability and neoplastic instability, the underlying pathology of each requires a different approach. Traumatic cervical spine injuries must be broken down into upper and lower cervical spine injuries, and the stability is predicated on both the boney and ligamentous injury. This article will go through the different fracture patterns and discuss the stability of each one. Additionally, it will discuss the important biomechanical and clinical issues that lead to the diagnosis of metastatic instability in the cervical spine.     

Double Noncontiguous Cervical Spinal Injuries

Summary. Summary.   Background: Double noncontiguous spinal injuries in the same patient, the first at the cervical level and the second at the thoracic or thoracolumbar level are not uncommon. On the other hand the incidence of double noncontiguous cervical injuries in low and these injuries imply complex mechanisms. This study investigates the cases of double noncontiguous cervical lesions in 342 cases of acute cervical injuries.   Method: An analysis of 342 patients with cervical injuries found 67 multiple cervical injuries and only 11 cases of double noncontiguous cervical lesions.   Findings and Interpretation: Double noncontiguous cervical injuries have a frequency of 3.2% in this study and in three cases there were pre-existing benign cervical lesions. A possible spinal biomechanical behaviour during injury can be that the first lesion appears because of the traumatic impact and there is a uniform transmission of the remaining traumatic strain all along the spine. It seems that the propagated force finds a spinal zone where the spinal resistance is diminished and the second spinal lesion can occur. Spinal vulnerability for the second lesion in the same trauma can be caused by a pre-existing benign spinal lesion or by a biomechanical discontinuity because of a particular posture at the traumatic moment. The second lesion in double noncontiguous cervical lesions can appear through a single great impact in pre-existing lesions, double impacts at the same time with injuries at two cervical levels or repeated cervical impacts in very quick succession in the same trauma. Published online July 18, 2002     

Trauma of the upper cervical spine: focus on vertical atlantoaxial dislocation

Purpose

Traumatic ligament injuries of the craniovertebral junction, either isolated or associated with bone avulsion or fracture, often lead to death. These injuries are rare and underrated but are increasingly seen in emergency departments due to the improvement in initial on-scene management of accidents. Vertical atlantoaxial dislocation (AAD) is a specific lesion that was barely reported. Based on our experience, our goal was to systematically investigate the prevalence and prognosis of traumatic vertical AAD and discuss its management.

Methods

All cervical CT scans performed at our institution between 2006 and 2010 for cervical trauma in adults were retrospectively reviewed. Based on the measurement of lateral mass index (LMI), defined as the gap between C1 and C2 articular facets, we identified three cases of traumatic vertical AAD in 300 CT scans. Their medical records were investigated.

Results

The incidence of vertical AAD was 1 % in the exposed population. One case was an isolated vertical AAD and two were associated with a type II odontoid fracture. We report the first case in the literature of unilateral vertical AAD. Two patients died rapidly; the survivor was treated with occipitocervical fixation. Specific maneuvers were used for immobilization and reduction.

Conclusions

This study found a not insignificant incidence of vertical AAD and a high lethality rate. LMI appears to be a relevant radiological criterion for this diagnosis, for which traction is contraindicated. Associated neurological or vascular damage should be suspected and investigated. In our experience, spinal surgical fixation is required because of major instability.     

The influence of transoral odontoid resection on stability of the craniovertebral junction.

Twenty-seven cases of craniovertebral junction compression treated with transoral surgery were reviewed to assess the influences of pathological processes and surgical interventions on spinal stability. All patients presented with signs and symptoms of spinal-cord or brain-stem dysfunction. Pathology included rheumatoid arthritis in 11 patients, congenital osseous malformations in 11, spinal fractures in two, plasmacytoma in one, osteomyelitis in one, and a gunshot injury in one. Instability was defined as clear radiographic evidence of mobile subluxation in conjunction with clinical assessment. Of 19 patients (70%) requiring internal fixation, nine underwent upper cervical fusion and 10 had occipitocervical fusion. When instability occurred, all subluxations were at the C1-2 level. There were no occipito-atlantal subluxations. Eight patients (30%) had preoperative instability of the craniovertebral junction due solely to their pathology, 11 patients (40%) suffered instability after transoral surgery, and eight (30%) were without clinical or radiographic evidence of instability (mean follow-up period 14 months). Craniovertebral junction instability predominated among patients with rheumatoid arthritis: 91% required fusion and 45% presented with pre-existing instability. Among individuals with congenital osseous malformations, 45% required fusion and only one patient (9%) had pre-existing instability. Patients who required subsequent posterior decompression of a Chiari malformation were at risk for developing instability; three of four became unstable after posterior decompression. Transoral resection of the dens, the anterior arch of C-1, and the lower clivus does not fully destabilize the spine; however, this operation may potentiate incipient pathological instability. The primary determinants of instability are the extent of pathological bone destruction, ligamentous weakening, and operative bone removal. Long-term follow-up monitoring is needed after transoral surgery to detect cases of late instability.     

Indications for surgery in upper cervical spine injury

20% of all spine injuries are cervical spine injuries. Surgical treatment of these injuries must take into account the great mobility of this part of the spinal column. Therefore, biomechanical aspects must be considered, especially in the upper cervical spine — C1 and C2. Describing our own therapeutical regimen in 35 patients with unstable upper cervical spine injuries we explain the biomechanical background and review the literature. It becomes evident that ventral approaches are superior to dorsal techniques for decompression, reposition, and stabilization with minimal loss of mobility.     

Which traumatic spinal injury creates which degree of instability? A systematic quantitative review

BACKGROUND CONTEXTTraumatic spinal injuries often require surgical fixation. Specific three-dimensional degrees of instability after spinal injury, which represent criteria for optimum treatment concepts, however, are still not well investigated.PURPOSEThe aim of this review therefore was to summarize and quantify multiplanar instability increases due to spinal injury from experimental studies.STUDY DESIGN/SETTINGSystematic review.METHODSA systematic review of the literature was performed using keyword-based search on PubMed and Web of Science databases in order to detect all in vitro studies investigating the destabilizing effect of simulated and provoked traumatic injury in human spine specimens. Together with the experimental designs, the instability parameters range of motion, neutral zone and translation were extracted from the studies and evaluated regarding type and level of injury.RESULTSA total of 59 studies was included in this review, of which 43 studies investigated the effect of cervical spine injury. Range of motion increase, which was reported in 58 studies, was generally lower compared to the neutral zone increase, given in 37 studies, despite of injury type and level. Instability increases were highest in flexion/extension for most injury types, while axial rotation was predominantly affected after cervical unilateral dislocation injury and lateral bending solely after odontoid fracture. Whiplash injuries and wedge fractures were found to increase instability equally in all motion planes.CONCLUSIONSSpecific traumatic spinal injuries produce characteristic but complex three-dimensional degrees of instability, which depend on the type, level, and morphology of the injury. Future studies should expand research on the cervicothoracic, thoracic, and lumbosacral spine and should additionally investigate the destabilizing effects of the injury morphology as well as concomitant rib cage injuries in case of thoracic spinal injuries. Moreover, neutral zone and translation should be measured in addition to the range of motion, while mechanical injury simulation should be preferred to resection or transection of structures to ensure high comparability with the clinical situation.     

Traumatic instabilities of the cervical spine caused by high-speed axial compression in a human model. An in vitro biomechanical study

STUDY DESIGN: Traumatic injury of the cervical spine was produced on human cadavers and evaluated with instability tests and radiographs. OBJECTIVE: To relate traumatic injuries of the cervical spine to instability and patterns of traumatic injury to different levels of impact energy. SUMMARY OF BACKGROUND DATA: Data from young human cadavers are rare in traumatic models of the cervical spine, and instabilities caused by axial compression with different impacts remain unknown. METHODS: Fourteen cervical spine specimens (C2-C4) obtained from fresh human cadavers were divided evenly into two groups and subjected to axial compressive impact with 30 J and 50 J impact energy, respectively. Pure moments in flexion-extension, left/right lateral bending, and left/right axial rotation were applied to each specimen before and after trauma. The maximum moment was 2.0 Nm in each case. Ranges of motion and neutral zones were measured using stereophotogrammetry. RESULTS: Ranges of motion and neutral zones for both groups increased after trauma. No bony injury was observed on the radiographs after trauma with 30 J, but motions increased significantly in flexion, extension, and axial rotation. All specimens showed bony injuries after trauma with 50 J, whereas motions continued to increase significantly in all directions. The relative neutral zone values were larger than the corresponding range of motion values, except in flexion-extension after trauma with 50 J. CONCLUSIONS: The injury patterns of the cervical spine were associated with impact energy, and a high level of impact energy could produce either three-column injury or anterior middle-column injury. Instabilities of the cervical spine caused by compressive trauma increased with the level of impact energy. The neutral zone was more sensitive than the range of motion in representing spinal instability, whereas instability testing was more sensitive than radiographs in evaluating traumatic injury of cervical spine.     

Microsurgical excision of a retro-odontoid disc hernia via a far-lateral approach: successful treatment of a rare cause of myelopathy: case report

OBJECTIVE AND IMPORTANCE: Among mass lesions causing myelopathy at the craniovertebral junction, retro-odontoid intervertebral disc hernias are very rare, with only four such cases reported in the literature. CLINICAL PRESENTATION: A 77-year-old woman with this rare condition complained of motor and sensory disturbances in her extremities. Magnetic resonance imaging scans demonstrated an extradural mass lesion at the craniovertebral junction, compressing the lower medulla oblongata and the upper cervical cord posteriorly. INTERVENTION: The lesion, which was partly mucinous cartilaginous and partly fatty and fibrous, was meticulously removed via a left far-lateral approach. The lesion was not neoplastic but was determined to be composed of fibrocartilaginous tissue, consistent with disc material. Postoperatively, the patient's sensory disturbances and motor weakness improved, and magnetic resonance imaging scans demonstrated marked shrinkage of the lesion. CONCLUSION: Sagittal, T1-weighted, magnetic resonance imaging scans demonstrated a low-intensity band between the odontoid process and the body of the axis, which suggested a persistent cartilaginous band. Although upward migration of a herniated disc from the lower cervical spine and degeneration of retro-odontoid ligaments might be possible causes, a persistent cartilaginous band extending between the odontoid process and the body of the axis was considered to be the more likely origin of the retro-odontoid intervertebral disc hernia. Because the far-lateral surgical approach does not require retraction of the cervical cord and provides safe access to the lesion at the craniovertebral junction, it is a suitable surgical method for this condition.     

An intradural arachnoid cyst of the craniovertebral junction; a case report]

An intradural arachnoid cyst of the craniovertebral junction possibly of traumatic origin is reported. A 59-year-old man was admitted to our hospital with a 10-month history of progressive gait disturbance. He had a history of head injury with a fracture of the occipital bone. Myelography revealed pooling of the contrast medium in the posterior fossa and on the dorsal sides of C1 and C2. Metrizamide-enhanced computed tomography also showed pooling at the same level. Magnetic resonance imaging indicated a large cystic lesion at the craniovertebral junction. Craniectomy of the posterior fossa and laminectomy of C1, C2 and C3 were performed, and an intradural cyst with thickened dura and arachnoid was found. The cyst wall was opened to communicate with the subarachnoid space. Histological findings of the specimen showed that the arachnoid was thickened. There are over 130 reports of intradural arachnoid cyst of the spine, but those of traumatic origin are rare, and cysts located in the intracranial to spinal region are extremely rare.     

Fatal basilar artery thrombosis after traumatic cervical facet dislocation. Case report

The authors detail a rare case of basilar artery thrombosis in a patient with traumatic cervical spine facet dislocation. Although the patient's deficits could initially be explained by the spinal injury, deterioration to a "locked-in-state" could not. In addition to vertebral artery injuries, the basilar artery can also be indirectly involved in cases of cervical spine trauma. In the rare viable patient, immediate reduction of cervical spine dislocation may allow endovascular thrombolysis, if not otherwise contraindicated.     

The craniovertebral junction area and the role of the ligaments and membranes

Traumatic injuries of the craniovertebral junction (CVJ) area are common and frequently the outcome of motor vehicle accidents, falls, and diving accidents. To define and characterize CVJ traumatic injuries, some international classifications are currently in use, and they are thought and focused on junction bone fracture. However, recent data point out a major important role of the CVJ ligaments and membranes in traumatic injuries with a secondary function of the osseous structures. Emphasizing the correct role of the ligaments and membranes is extremely important for determining appropriate medical or surgical planning for patients and also to design new CVJ injury classifications. We reviewed every recent major publication on the ligaments and membranes of the CVJ area. We divided the information into sections concerning anatomy, embryology, biomechanics, trauma, and CVJ bone fractures. A role of the ligaments and membranes in the traumatic injuries of the CVJ area has often been recognized; but only recently, with the increase in the knowledge of the anatomic and biomechanical junction area, supported by neuroradiological tools (magnetic resonance imaging) and a more detailed traumatic injuries assessment, has the role of the ligaments and membranes been highlighted. Ligaments and membranes have a pivotal role in each junctional ability and are the key to orienting any medical or surgical indications in this unique area of the spine.     

颈椎损伤生物力学研究进展

在生物力学领域，颈椎损伤的研究近年较受关注。利用生物力学的知识可帮助我们判断损伤后颈椎的稳定性，认识其影响因素，并对损伤进行恰当的分类。本文还介绍了椎体刚度、损伤前的生物力学特征(曲度、质量、惯性特征等)对颈椎损伤的影响、损伤时椎管的变化，以及近年发展较快的颈椎损伤的有限元模型研究等。     

Finite element analysis of cervical spinal instability under physiologic loading

The definition of cervical spinal instability has been a subject of considerable debate and has not been clearly established. Stability of the motion segment is provided by ligaments, facet joints, and disc, which restrict range of movement. Moreover, permanent damage to one of the stabilizing structures alters the roles of the other two. Although many studies have been conducted to investigate cervical injuries, to date there are only limited finite element investigations reported in the literature on the biomechanical response of the cervical spine in these respects. A comprehensive, geometric, nonlinear finite element model of the lower cervical spine has been successfully developed and validated under compression, anterior-posterior shear, and sagittal moments. Injury studies were done by varying each spinal component independently from the validated model. Seven analyses were conducted for each injury simulation (model without ligaments, model without facets, model without facets and ligaments, and model without disc nucleus). Results indicate that the role of the ligaments in resisting anterior and posterior shear and flexion and axial rotation moments is important. Under other physiologic loading (anterior-posterior shear, flexion-extension, lateral bending, and axial rotation), the disc nucleus is responsible for the initial stiffness of the cervical spine. The results also highlight the importance of facets in resisting compression at higher loads, anterior shear, extension, lateral bending, and torsion. The results provide new insight through injury simulation into the role of the various spinal components in providing cervical spinal stability. These findings seem to correlate well with experimental results as well as with common clinical experience.     

Cervicomedullary junction decompression in a case of Marshall-Smith syndrome. Case report

The case is reported of a 2-year-old boy born with Marshall-Smith syndrome who had difficulty in swallowing and who exhibited spasticity and quadriparesis due to compression of the medulla and cervical spine. This is the first child with this rare condition reported to have brain-stem compression from bone abnormalities at the craniovertebral junction and who has required surgery.     

Cervical spine injury in patients with ankylosing spondylitis.

Fractures of the cervical spine associated with ankylosing spondylitis are rare. Relatively minor injury can cause a fracture of the vertebral body or through the ossified intervertebral space, because of the loss of normal flexibility, mobility, and elasticity in the rigid spine. Sixty-six per cent of the fracture subluxations of the ankylosed spine are associated with injury to the spinal cord, and the mortality rate is 40%. Because of the complete nature of fracture and instability, there is a high risk of neurologic deterioration. Immobilization of the cervical spine in a Halo cast appears to be the treatment of choice. If skull traction is applied the cervical spine should be immobilized in the neutral position, and overzealous traction exceeding 10 pounds should be avoided. Callus formation and fracture healing following immobilization is rapid. Four new cases are described and 44 previously reported cases in the literature have been reviewed.     

Ventral cervicomedullary junction compression secondary to condylus occipitalis (median occipital condyle), a rare entity

OBJECTIVE: Condylus occipitalis is presented in postmortem anatomic studies. There is no clinical study in the literature. Myelopathy due to anomalies of the craniovertebral junction is rare in neurosurgical practices. To our knowledge, myelopathy due to condylus occipitalis has not been reported before. Deaths of two cases were previously reported, but these were not live cases. METHODS: We describe the case of a 40-year-old woman presenting with progressive myelopathy related to condylus occipitalis located in the anterior foramen magnum region. RESULTS: Magnetic resonance imaging and computed tomography showed the condylus occipitalis, marked stenosis of the spinal canal at the level of the atlas, with cord compression and evidence of myelopathy. We performed posterior decompression without fusion and duraplasty. Because the cervicomedullary compression syndrome was not resolved, a transoral decompression could not be done owing to pulmonary insufficiency. CONCLUSIONS: This unique clinical article (a live case), not anatomic, presents a very rare abnormality of the craniovertebral junction. Myelopathy is a very important complication of this congenital craniovertebral junction abnormality. Posterior decompression seems not to be effective for myelopathy due to condylus occipitalis. In our opinion, anterior decompression is needed in this condition. A larger series will be needed to better define its role in the management of this anomaly.     

Classification of spinal injuries based on the essential traumatic spinal mechanisms

STUDY DESIGN: A biomechanical unitary classification of spinal injuries is proposed. OBJECTIVE: To present an evaluation of spinal injuries based on the essential traumatic spinal mechanisms: axial deformation, torsion, translation and combined mechanisms in connection with the concept of the stabilizing axial spinal pillar. SETTING: Hospital 'Sf. Treime', Iasi, Romania. METHODS: The essential mechanisms of spinal injuries are considered: (1) axial deformation with (a) compression (centric or eccentric), most often eccentric, including compression in flexion or extension; (b) spinal elongation with distraction as centric elongation, but frequently axial eccentric elongation and a flexion or extension injury; (2) torsion or axial spinal rotation, (3) segmental translation, with a shearing version for the double translation and (4) combined mechanisms - the most frequent situation. Over 300 patients with spinal injuries were analysed and the spinal instability was determined using the criteria of clinical instability. The cases of spinal instability were studied in connection with the types of lesion of the central axial spinal pillar. RESULTS: All cases with lesions of the central axial spinal pillar had traumatic spinal instability. The spinal instability was absent in cases of isolated lesions of the anterior or posterior secondary pillar. The X-ray and spinal CT analysis of the traumatic spinal lesions showed the types of lesions and specified the mechanisms of spinal injuries. The combined mechanisms were responsible for the majority of the spinal injuries. CONCLUSIONS: Spinal instability occurs because of the lesion of the central axial spinal pillar The types of lesions of the central spinal pillar and of the secondary spinal pillars are determined by the essential traumatic spinal mechanisms: axial deformation (with compression or elongation), axial rotation, translation and most frequently the above combined mechanisms.     

Cervical spine trauma in patients with trisomy 21

Atlantoaxial subluxation is predominantly found in trisomy 21. While neurological symptoms occur less frequently, fatal atlantoaxial instability with spinal cord compression has been described in trisomy 21 after minor trauma of the cervical spine. Presenting a special case we could demonstrate that atlantoaxial instability has to be ruled out in patients with trisomy 21 suffering from acute cervical spine trauma. We further recommend primary posterior fusion if the biomechanical stability of the atlantoaxial complex remains unclear after clinical and radiological exploration.     

Spinal clearance in the difficult trauma patient: a role for screening MRI of the spine

Identifying spinal injuries in trauma patients with altered mental status can be difficult. CT scanning and clinical examination are the basis of our spinal clearance, but screening "trauma protocol" spinal MRI is used to exclude occult injuries. We sought to evaluate the sensitivity of CT scanning for spinal injuries compared with our MRI protocol. Ninety-seven patients underwent MRI cervical spine trauma protocol during 2004. Twenty-nine patients were obtunded, 29 had neurologic symptoms, and 39 had spine pain. MRI confirmed the initial CT findings without new injuries in 83 cases. MRI reclassified fractures as degenerative changes in 12 cases. In 2 cases, the MRI identified new injuries: one a stable partial ligament tear, the second a T7 Chance fracture with ligamental disruption requiring operative fixation. There was no morbidity or mortality documented in obtaining the MRI studies. Overall negative predictive value of CT scanning of the spine was 98 per cent, the positive predictive value was 78 per cent, and the sensitivity and specificity was 94 per cent and 91 per cent, respectively. CT scanning of the cervical and axial spine is sensitive for spinal trauma but not specific. MRI trauma protocol should be reserved for cases when initial CT scanning is suggestive of traumatic injury.     

High Grade Infective Spondylolisthesis of Cervical Spine Secondary to Tuberculosis

Spondylolisthesis coexisting with tuberculosis is rarely reported. There is a controversy whether spondylolisthesis coexists or precedes tuberculosis. Few cases of pathological spondylolisthesis secondary to tuberculous spondylodiscitis have been reported in the lumbar and lumbosacral spine. All cases in the literature presented as anterolisthesis, except one which presented as posterolisthesis of lumbar spine. Spondylolisthesis in the cervical spine is mainly degenerative and traumatic. Spondylolisthesis due to tuberculosis is not reported in the lower cervical spine. The exact mechanism of such an occurrence of spondylolisthesis with tuberculosis is sparsely reported in the literature and inadequately understood. We report a rare case of high grade pathological posterolisthesis of the lower cervical spine due to tubercular spondylodiscitis in a 67-year-old woman managed surgically with a three-year follow-up period. This case highlights the varied and complex presentation of tuberculosis of the lower cervical spine and gives insight into its pathogenesis, diagnosis, and management.