Summary Cervical facet dislocations and fractures represent a spectrum of traumatic injuries with varying degrees of cervical instability and risk of spinal cord injury Diagnosis can be confirmed with radiographs or CT scan. An MRI should be performed before surgery to identify an associated disc herniation Treatment usually involves closed or open reduction, followed by surgical stabilization Epidemiology Demographics high-energy trauma in the young motor vehicle and motorcycle accidents login to view 1 more bullet contact sports injuries low-energy trauma in the elderly Anatomic location 17% of all injuries are fractures of C7 or dislocation at the C7-T1 junction reinforces the need to obtain radiographic visualization of the cervicothoracic junction Etiology Pathoanatomy represent a spectrum of osteoligamentous pathology that includes facet fractures login to view 4 more bullets unilateral facet dislocation login to view 4 more bullets bilateral facet dislocation login to view 2 more bullets mechanism flexion and distraction forces +/- an element of rotation login to view 1 more bullet Associated injuries head injuries noncontiguous spinal injuries often occur in the thoracolumbar, cervicothoracic, and occipitocervical junction appendicular injuries Classification Descriptive (subaxial cervical spine injuries) includes compression fracture burst fracture flexion-distraction injury facet dislocation (unilateral or bilateral) facet fracture more commonly used in the clinical setting Allen and Ferguson Classification (subaxial cervical spine injuries) Typically used for research and not in a clinical setting Based solely on static radiographs and mechanisms of injury 1. Flexion-compression 2. Vertical compression 3. Flexion-distraction Stage 1: Facet sprain with slight subluxation, focal kyphosis <10° Stage 2: Unilateral facet dislocation Stage 3: Bilateral facet dislocation with 50% displacement (perched facets) Stage 4: Complete dislocation (100% displacement) 4. Extension-compression 5. Extension-distraction 6. Lateral flexion Presentation History history of trauma involving a flexion-distraction mechanism obtain relevant past history ankylosing spondylitis/DISH previous cervical spine fusion Symptoms pain neck pain in setting of a flexion-distraction mechanism unilateral dislocation numbness and tingling radiating down a single arm login to view 2 more bullets bilateral dislocation subjective weakness of the bilateral upper and lower extremities paresthesias and sensory changes in bilateral lower extremities Physical exam inspection gross spinal alignment login to view 1 more bullet scalp and head lacerations or contusions login to view 1 more bullet monoradiculopathy seen in patients with unilateral dislocations login to view 8 more bullets spinal cord injury symptoms seen with bilateral dislocations symptoms worsen with increasing subluxation perform thorough neurologic examination login to view 3 more bullets Imaging Radiographs views AP, lateral, oblique, and open-mouth odontoid findings lateral x-ray shows subluxation of vertebral bodies unilateral facet dislocation leads to ~25% subluxation on x-ray bilateral facet dislocation leads to ~50% subluxation on x-ray loss of disc height might indicate retropulsed disc in canal widening of the interspinous distance hypolordosis, especially at the injury level soft tissue swelling additional views flexion-extension lateral radiographs login to view 2 more bullets CT scan indications most cases findings bony anatomy of the injury malalignment or subtle subluxation of facet facet fracture associated fractures of the pedicle or lamina MRI indications acute facet dislocation in patient with altered mental status login to view 1 more bullet failed closed reduction and before open reduction to look for disc herniation any neurologic deterioration seen during closed reduction any patient going to OR for surgical stabilization needs an MRI in advance timing (controversial) timing of MRI depends on severity and progression of neurologic injury MRI should always be performed prior to open reduction or surgical stabilization login to view 1 more bullet findings disc herniations login to view 1 more bullet extent of posterior ligamentous injury login to view 5 more bullets spinal cord compression or myelomalacia spinal cord hematoma login to view 1 more bullet Differential Cervical lateral mass fracture separation important to identify as cervical lateral mass fracture separations require fusing two levels, while a facet dislocation only requires fusing a single level Treatment Nonoperative external immobilization x6-12 weeks indications login to view 3 more bullets technique login to view 1 more bullet outcomes login to view 3 more bullets Operative single level instrumented stabilization indications login to view 3 more bullets technique login to view 1 more bullet emergent closed reduction, emergent MRI, then urgent surgical stabilization indications login to view 3 more bullets timing login to view 2 more bullets technique login to view 24 more bullets emergent MRI then emergent open reduction surgical stabilization indications login to view 2 more bullets technique login to view 2 more bullets Techniques Halo external immobilization technique halo is suboptimal in lower cervical spine; therefore, hard orthosis may be satisfactory without complications associated with a halo requires close radiographic follow-up login to view 1 more bullet morbidly obese patients may not fit or be adequately stabilized in a halo brace Closed reduction requirements adequate anesthesia sedation supervision of respiratory function serial cross-table laterals ability to perform serial neurologic examinations technique application of Gardner-Wells tongs login to view 3 more bullets gradually increase axial traction with the addition of weights login to view 3 more bullets a component of cervical flexion can facilitate reduction login to view 1 more bullet once reduced, decrease traction weight to between 10-15 lbs. and apply an extension moment to the cervical spine login to view 2 more bullets perform serial neurologic exams and plain radiographs after each weight addition login to view 2 more bullets can switch to carbon fiber Gardner-Wells tongs if need to obtain MRI in traction login to view 1 more bullet abort if neurologic exam worsens and obtain immediate MRI Anterior cervical discectomy and fusion +/- open reduction indications facet dislocations reduced through closed methods with an MRI showing cervical disc herniation and significant compression on the spinal cord unilateral facet dislocations that fail closed reduction with a disc herniation and significant compression on the spinal cord anterior open reduction techniques can be used to reduce a unilateral facet dislocation standard Smith-Robinson approach login to view 2 more bullets unilateral dislocations can be reduced by distracting vertebral bodies with Caspar pins and then rotating the proximal pin towards the side of the dislocation bilateral dislocations can be reduced by placing converging Caspar pins (10-20° angle) and then compressing the ends together to unlock the facets login to view 1 more bullet alternatively, lamina spreaders applied to the endplates not effective for reducing bilateral facet dislocations pros and cons overdistraction of the disc space login to view 5 more bullets Posterior instrumented stabilization +/- open reduction indications when unable to reduce by closed or anterior approach no anterior compression of spinal cord (no disc herniation) technique instrumentation performed with lateral mass screws reduction login to view 3 more bullets usually have to fuse two levels due to inadequate lateral mass purchase at the level of dislocation Combined anterior decompression and posterior reduction / stabilization technique anterior approach first, perform discectomy, position plate, only fix plate to superior vertebral body login to view 2 more bullets Complications Surgical site infections increased risk with posterior surgery tissue trauma from injury increases risk of infection Recurrent dislocation unilateral dislocations treated with immobilization treated with anterior discectomy, reduction, and interbody fusion Respiratory complications ARDS higher risk in the multitraumatized patient pneumonia due to prolonged recumbency possible need for tracheostomy Vertebral artery injury occurs in up to 11% of patients with cervical spine injuries increased risk when injury involves lateral mass and transverse process often go unrecognized and untreated Esophageal injury related to anterior reduction and fixation primary repair with thoracic surgeon upon identification Pin tract infections associated with halo vest immobilization can result in decreased pin purchase can rarely result in meningitis if the inner table of the skull is violated treat with local care and antibiotics Prognosis Neurologic recovery lower probability of motor improvement with increasingly severe neurologic injury increased age associated with decreased neurologic recovery poor motor recovery potential with spinal cord hematoma