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At the center of this controversy is the initial management of these patients upon arrival at the emergency department. One opinion favors expeditious reduction of these injuries with closed techniques when a patient is awake and cooperative, with the goal of immediate spinal canal decompression.1 The other opinion is to acquire initial advanced spinal imaging in the form of magnetic resonance imaging (MRI) prior to manipulation of the spinal canal for fear of neurological injury in the presence of an extruded disk that may be further displaced into the spinal canal during the process of reduction.² Although both groups have reasonable arguments supporting their viewpoints, ultimately which group you belong to will often affect the surgical approach you choose to care for the patient.

Interpretation of the MRI for the presence of a disk herniation in cervical dislocations is also highly variable.³ If a disk herniation is present, many surgeons prefer an anterior approach, with diskectomy prior to reduction. Although there are techniques for anterior open reduction, if these fail, the patient is often obligated to an anterior, posterior, then anterior procedure to obtain adequate reduction and anterior and posterior fixation. Critics of obtaining an MRI scan prior to reduction cite that this probably leads to certain patients being overtreated with multistage procedures. If a closed reduction is successfully performed, then an anterior or posterior approach can be performed for stabilization in a more elective manner. We will discuss factors influencing the surgeon’s choice of surgical approach as well as the literature currently available for review.

Background

Unilateral and bilateral cervical facet dislocations below C2 are often due to flexion and distraction forces on the cervical spine. These injuries are often associated with ligamentous disruption, fracture, disk herniation, or vascular and neural injury. Unilateral cervical facet dislocations commonly demonstrate no neurological deficit or nerve root injury. Bilateral facet dislocations are often associated with more significant neurological deficit. The most common levels of injury are C6–C7 and C5–C6.⁴

Allen and Ferguson proposed a four-stage classification system that includes facet subluxation, 25% translation of the cranial relative to the caudal vertebrae with unilateral facet dislocation, 50% translation with bilateral facet dislocation, and lastly complete dislocation.⁵

Diagnostic imaging is controversial. Traditionally, radiographic evaluation with a cross-table lateral view was employed. The inability to obtain adequate radiographs including the cervical–thoracic junction, a modest incidence of missed fractures, as well as the advent and availability of helical computed tomography (CT) and MRI, has resulted in plain radiography falling out of favor. McCullogh et al noted that plain radiographs missed nearly 50% of cervical fractures compared with 2% in patients who underwent CT scanning.⁶ Even with the detail offered by CT, there is still variability in how these injuries are interpreted. Dailey et al measured observer variability among spinal traumatologists between CT and intraoperative findings. They noted only moderate interobserver reliability and good validity when differentiating unilateral and bilateral dislocations.⁷

Obtaining an MRI scan postinjury continues to be a point of debate. As noted previously, cervical facet dislocations are commonly associated with soft tissue injury, including disk herniation. Reports of disk herniation associated with cervical dislocation range from 0.7% to 42%.8 The presence of disk herniation does not necessarily correlate with the presence of a neurological deficit. The great fear is that the presence of an intervertebral disk herniation may result in neurological deficit as the herniated disk is displaced into the spinal canal during the reduction maneuver. Eismont et al reviewed six cases among 68 patients between July 1980 to August 1987 who were diagnosed with cervical subluxation or dislocation of the facet joints and found to have associated herniated cervical disks. All patients underwent closed reduction with traction, of which two were unsuccessful. Both these patients proceeded to open reduction through a posterior approach. The first patient had initially presented with an incomplete neurological deficit; however, postoperatively, the patient awoke with complete quadriplegia. Emergent myelography revealed severe compression of the spinal cord by a herniated intervertebral disk. The second patient underwent open posterior reduction with the aid of sonography to monitor any further displacement of a herniated disk. A herniated disk was found and the approach was aborted for an anterior decompression followed by anterior arthrodesis.² Vaccaro et al, on the other hand, prospectively evaluated 11 patients with cervical spine dislocation prior to closed reduction that underwent pre- and postreduction MRI. It was noted that two of 11 patients had disk herniations prior to reduction. Of the nine successful reductions, five disk herniations were found posttraction; however, no neurological worsening was noted after reduction. They concluded that disk herniations may be increased with closed traction reduction; however, this did not affect their ability to safely reduce these injuries in an awake and cooperative patient.¹ In a recent study by Darsaut et al, 17 patients with cervical fracture dislocations underwent closed reduction with traction in an MRI scanner between 1999 and 2003. Prereduction, 15 patients had disruption of the disk at the level of the dislocation, and four had a discrete posterior herniation. Sequential MRI scans were obtained as the distracting force was increased. Postreduction all herniated disk material returned within the disk space. There were no neurological sequelae in any of the 17 patients. The authors concluded that closed reduction is a safe treatment and effective in achieving immediate spinal canal decompression.⁹

Grauer et al utilized a questionnaire study whereby 10 clinical vignettes with and without corresponding MRI scans and varying degrees of spinal cord injury were presented to 25 spine surgeons. The questionnaire analyzed the need for further imaging as well as treatment approach. Their study noted lack of consensus regarding immediate closed versus open treatment and the need for MRI prior to closed reduction. When an MRI scan was available, there still was lack of consensus regarding closed versus open treatment.³

Treatment of unilateral or bilateral cervical facet dislocation includes closed reduction followed by external orthotic immobilization or open arthrodesis. Others propose direct open reduction of the deformity and fusion through either an anterior or a posterior approach. Neurological status influences the timing and option chosen. Hart suggests that patients who present with complete or near complete neurological loss should undergo immediate closed reduction given this patient population has the least to lose and the highest possibility of neurological functional recovery. However, when there is incomplete or normal neurological function, immediate closed reduction versus MRI or open reduction remains controversial.¹⁰

Closed reduction remains the most common initial treatment for these injuries.¹¹ Methods include awake or sedated traction versus manual manipulation. Sedated traction has fallen out of favor due to the inability to monitor the neurological exam and possibility of unrecognized neurological worsening. Cotler et al reviewed closed reduction in a series of 24 awake and cooperative neurologically normal patients with subaxial cervical facet dislocations. They used Gardner-Wells skull tong traction to apply increasing weight until closed reduction was achieved (up to 140 lb applied), with neurological exam carefully monitored after each increase in weight. All patients did well and underwent successful reduction without neurological deterioration. After reduction, surgical stabilization can be done in a less emergent fashion.¹²

Failed closed reductions require open reduction. Choice of surgical fixation and fusion approach is controversial, including anterior, posterior, or combined approaches. This debate is also present if the surgeon proceeds directly to an open reduction bypassing closed reduction. The choice of surgical approach depends on multiple factors, including neurological status, injury pattern, and presence of a disk herniation.

Surgical stabilization of these injuries is favored due to the poor outcomes with nonsurgical management. Koivikko et al compared the clinical outcome of patients with subaxial cervical fracture dislocation treated nonsurgically with halo vest or collar versus patients who underwent posterior fusion and interspinous wiring between 1977 and 1998. Thirtynine of the 55 patients treated conservatively underwent traction followed by collar application, nine underwent halo vest application, and seven patients were placed in a collar directly without attempted reduction. Fifty-one patients underwent surgical intervention with posterior fusion and interspinous wiring. Median follow-up was 12 months in both groups. Neurological outcomes were similar in both groups. Their study noted that surgical intervention resulted in improved anatomical results with complication rates comparable to conservative treatment methods. Nearly 30% of those patients treated conservatively presented with late deformities and instability. They found late neck pain correlated with residual displacement. As such, patients treated conservatively had greater complaints of neck pain because they had less of an anatomical reduction compared with those surgically treated. The authors concluded that surgical stabilization of these patients is preferred.13

Table 7.1 Summary of Level of Evidence of Published Studies

The majority of the articles available for review provided level III or IV evidence. There are also several level V studies describing new techniques for the treatment of these injuries. There were no level I studies identified. There was one level II study (Table 7.1).

Anterior Approach

Anterior cervical decompression and fusion/fixation has gained popularity in conjunction or even in place of posterior fixation/fusion. Advocates of the anterior approach cite the ability to directly assess an associated herniated disk and perform decompression, less muscle dissection, and the ability to place a large graft under compressive load for fusion after diskectomy, and need to immobilize only one motion segment.

Level I Data

Currently none to date

Level II Data

Currently there is one study that compares the anterior and posterior approach. Brodke et al conducted a randomized study of 52 patients with unstable cervical spines. Patients included had unstable cervical injuries between C3 and C7, spinal cord injuries, and a minimum of a 6-month follow-up postoperatively. Patients excluded were those requiring a specific surgical approach and patients with radiculopathy or no neurological deficits. All patients underwent closed reduction successfully followed by surgical fusion, with 22 patients randomized to the anterior approach and 30 patients randomized to the posterior approach. Two patients expired and three were lost in follow-up with a resulting 47 patients. There was no statistically significant difference between the two groups in regard to age, gender, injury mechanism, or time to surgery. There were no differences in neurological outcomes, fusion rates, alignment, or long-term complaints of pain between both groups.¹⁴

Level III Data

There have been few level III studies investigating this topic. Several biomechanical studies currently dominate the literature. Grubb et al used porcine and cadaveric specimens to compare the stability of cervical spine locking and nonlocking plates. The study analyzed flexion, lateral bending, and torsional testing. Models had undergone corpectomy as well as posterior ligamentous releases. Results demonstrated the locking plate had significantly higher flexion and torsional stiffness as well as higher energy to failure compared with the nonlocking plate. The authors concluded that the cervical spine locking plate when compared with the Caspar nonlocking system was equivalent, if not more biomechanically stable.¹⁵

Level IV Data

Reindl et al retrospectively reviewed 41 patients over a 3- year period that underwent anterior open reduction as well as anterior plating and tricortical iliac crest autograft after undergoing attempted closed reduction. Of those, eight patients failed closed reduction and underwent anterior open reductions. Of these eight patients, two patients were unable to be successfully reduced from the anterior approach. They required posterior reduction. All patients went on to fusion at the most recent follow-up with neurological improvement observed in those patients with preoperative neurological deficits. The authors concluded that a majority of patients can successfully be open reduced and fused by use of the anterior approach.¹⁶

Razack et al reviewed 22 patients with single-level bilateral facet fracture dislocations from January 1993 to December 1998. Fifty percent had incomplete spinal cord injuries, and 6% had complete quadriplegia. All patients underwent reduction with traction followed by anterior cervical diskectomy with bone graft and titanium unicortical locking plate. The average follow-up was 32 months with minimum follow-up of 1 year. One patient was noted to have resorption of the graft; however, the patient went on to fusion without further surgical intervention. No patients were noted to be unstable at the level of instrumentation at latest follow-up. Ten of the 19 patients with neurological deficit had evidence of neurological recovery. The authors proposed that anterior fusion with unicortical instrumentation is acceptable after a reduction has occurred.17

Kim et al reviewed 65 patients who had bilateral cervical facet dislocations between March 1997 and February 2006. All patients underwent attempted closed reduction. Fortyseven of the 65 patients were successfully closed reduced. They subsequently underwent anterior cervical diskectomy with bicortical plate stabilization with autograft. The remaining 18 were reduced via an open posterior approach followed by anterior cervical stabilization with autograft. All patients demonstrated bony fusion at follow-up with no evidence of neurological decline or instability. The authors concluded that anterior cervical fixation for bilateral cervical facet dislocation is equivocal to combined anterior/posterior cervical fixation, even in patients with facet fractures.¹⁸

In another study, Johnson et al reviewed the radiographic findings and factors related to loss of alignment as well as pseudarthrosis. Eighty-seven patients with single-level unilateral or bilateral facet fracture dislocation who underwent anterior cervical diskectomy fusion and instrumentation and met inclusion criteria were identified between January 1994 and December 2001. Average follow-up was 32 weeks (range 2 to 112 weeks), with shorter follow-up due to failure. Failure was defined as translation greater than 3.5 mm or angulation of greater than 11 degrees. Sixty-five of the 87 patients had bilateral facet injury. Twenty-two of the 87 patients had unilateral facet injuries. Eleven patients (13%) had failed fixation according to their definition above. There was a strong correlation between radiographic failure and the presence of end plate fracture as well as facet fractures. There was no correlation between age, gender, surgeon, unilateral versus bilateral injury, plate type, level of injury, degree of translation, or sagittal alignment at the time of injury. The authors support the satisfactory outcomes of anterior plating; however, when these injuries are associated with facet fractures or end plate compression fractures, they suggest that posterior fusion and/or instrumentation should be considered.¹⁹

Some surgeons proceed directly to open reduction. Payer and Tessitore advocated that this avoids the time loss for attempted reduction or further imaging studies such as MRI. All five patients in the study underwent anterior open reduction along with both anterior and posterior instrumentation and fusion. Four of the five patients presented with tetraplegia, and the remaining patient was neurologically intact. All patients showed fusion at the latest follow-up as well as no further neurological decline. Average follow-up was 15 months.⁴

Level V

New anterior techniques continue to be developed. A novel technique described by Ordonez et al proposes immediate operative intervention with anterior decompression followed by reduction in 10 patients. All patients underwent plain radiographs, CT imaging, and MRI prior to surgical intervention. If unsuccessful reduction was encountered, vertebral body posts such as Caspar pins were placed 10 to 20 degrees convergent relative to each other (Fig. 7.1). Forced kyphosis followed by distraction and reduction for bilateral facet dislocation versus rotatory distraction for unilateral facet dislocation was employed. The interbody graft was placed after reduction was obtained followed by anterior instrumentation. This technique was used in 10 patients, of which six improved neurologically and four remained unchanged. Nine of 10 patients were successfully reduced anteriorly by the foregoing procedure, and one required posterior reduction. Of note, five of the 10 patients had traumatic disk herniation at presentation. The authors concluded that an anterior decompression, reduction, and stabilization is an option when significant posterior element disruption and comminuted facet fractures were absent.²⁰

Summary of Data

The anterior approach to either stabilize or reduce and stabilize bilateral or unilateral cervical facet dislocations has been shown to be successful when the anterior and/or posterior elements are not severally injured. Additionally this approach gives direct access to the spinal canal when decompression of a traumatic disk herniation is required. Based on the grading scale of Guyatt et al recommendations for an anterior approach is 1C.^20a

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