Fracture Dislocation at the Level of C6-C7: A Case Report and Literature Review

Fractures of the cervical spine can cause devastating long-term effects on patients. Spinal cord injuries can occur in up to 50% of cases in association with cervical spine fractures. Therefore, it is vital and of utmost importance to recognize cervical spine injuries early on to avoid the exacerbation of an existing injury and its detrimental effects on the patients. We report a case of a C6-C7 fracture dislocation with an associated neurological insult that improved dramatically following fixation and rehabilitation. Unfortunately, patients with this presentation may have long-term neurological insults rather than regain normal function; however, our case notes the importance of prompt intervention and its effect on the outcome.


Introduction
Cervical spine fractures can cause long-term effects on patients where almost 50% of spinal cord injuries have been reported in relation to cervical spine fractures [1][2][3][4][5][6][7][8][9][10]. Therefore, it is vital to identify cervical spine injuries as soon as possible to avoid exacerbating an existing injury and its possible long-term effects on the patients. Clayton et al. examined the possible predictors of cervical spine injuries and found that Motor Vehicle Collision (MVC), falls, age <40, pelvic fractures, and an Injury Severity Score (ISS) of >15 are significant individual predictors of cervical spine injury. Interestingly, neither facial fracture nor head injury alone correlated with a higher risk of cervical spine injury [11]. We report a case of a C6-C7 fracture dislocation with an associated neurological insult that improved dramatically following fixation and rehabilitation. We present the following case in accordance with the CARE reporting checklist.

Case Presentation
Our patient is a 41-year-old Saudi man with a history of a motor vehicle accident where he hit a camel on a desert road at the speed of 110 km/hr in September 2019. He presented to our emergency department complaining of severe neck pain and limitation of movement and was on C-collar. He had no previous significant medical or surgical history. After primary and secondary surveys, his physical examination revealed a right upper limb neurological deficit in the form of shoulder numbness, and a C5-T1 power of 3/5; whereas, his left upper limb and bilateral lower limbs were intact neurologically. He was controlling his sphincters and had no evident vascular injury. Images were taken for the patient upon admission; radiographs and CT images showed translation of the cervical at the level of C6-C7 of more than 75% anteriolisthesis ( Figure 1). The patient remained on C-collar, optimized and prepared for surgery. Moreover, the patient was observed under the care of the ICU, and was pushed to the operating room urgently in under 24 hours. Patient was put in prone position, prepping and draping were done in a sterile manner. The surgery began posteriorly, utilizing a posterior midline incision where facetectomy was done completely in the posterior part of C7. Afterwards, the patient was positioned supinely and draped again for the anterior approach for complete corepctomy and proper decompression at the level of C7 with mesh plating of C6-C7 and bone grafting, followed by close observation under the ICU for the next couple of days (Figures 4-5).

Discussion
We presented a case of grade 4 anterolisthesis at the level of C6-7 with incomplete right upper limb paralysis that regained normal neurological status at the latest follow up.
It is noted that cervical fracture dislocations most commonly occur at the level of C6-7 and C5-6 following trauma [12,13]. Falls seems to be the most common mode of injury in several papers [14,15]. Fredø et al. also noted a male predominance in cervical fractures, in addition to a mortality rate of 10% in the Norwegian population [14]. Axial load or a large compressive force applied to the top of the head is the major mechanism of serious cervical injury, more so when the neck is in slight flexion given that the spine is out of its normal lordotic alignment leading to improper distribution of force to the thorax, where the musculature cannot aid in absorbing the force due to the cervical spine being in a straight line due to flexion [16].
Adeolu et al. studied the effectiveness of closed reduction of cervical spine injuries using cervical traction and noted an improvement in the neurological function of 18.9% whilst the rest remained neurologically the same. He noted the causes of failure to be locking facets most commonly, old injuries, new-onset or worsening pain, and over-distraction. In addition, the complications of reduction in a closed manner were over-distraction most commonly, tong pull-out, new-onset or worsening pain, and finally skull perforation. However, they concluded that satisfactory reduction can be achieved in patients with cervical spine injuries and significant malalignment [17].
The sooner the spinal cord is stabilized with decompression of the injured spinal cord, the higher the chance of recovery [18,19]; reducing the fracture or dislocation will bring the vertebral canal back to its normal form and dimension leading to spinal cord decompression [18,20]. Abdelgawaad et al. [21] evaluated the efficacy of the anterior only approach for C F4 (AO classification) traumatic subaxial cervical spine injuries and concluded that cervical traumatic instability can be efficiently managed surgically with anterior decompression and fusion. They recommend the anterior approach in cases with neurological deficits, in patients with comorbidities, or when a short operative time is preferred. Zhou et al conducted a prospective study evaluating cervical pedicle screw fixation for fracture dislocation of the lower cervical spine and found that all participants had achieved solid bony fusion at six months follow up in addition to stable fixation of the related segments. In their paper, patients with complete spinal cord injury showed no improvement in neural function except for mild alleviation of pain and numbness; whereas patients with incomplete injury showed a grade or two on the Abbreviated Injury Scale (AIS) classification [22].
Recent guidelines necessitate surgery to achieve reduction and stabilization of the cervical spine and insure spinal cord decompression due to the instability naturally associated with dislocations [18,23]. Interestingly, not all fracture dislocations are managed immediately. According to Miao et al., treating old fracture dislocation of the lower cervical spine can be managed with completed decompression, immediate and longterm anterior cervical column support sequence, and physiological curvature of the cervical vertebra, in addition to restoring nerve function using anterior partial corpectomy, titanium mesh fusion, and internal fixation. When there are locked facet joints or posterior structures invading the vertebral canal, the combined anterior and posterior approaches should be performed in order to achieve better results [24].
It is, unfortunately, possible for some patients with a such presentation to end up with a long-term neurological deficit rather than regain normal function which is demonstrated in the cases found within the literature review in Table 1. It is therefore vital to approach such cases with a focused and efficient approach in order to maximize the possible benefits for the patients.  injuries.
which turned out to be MO of the right longus coli muscle which was managed by passive stretching, NSAIDs, antispasmodics, and a rigid cervical collar as tolerated. Moreover, the patient complained of persistent headaches; CT head showed chronic subdural hematomas, which were attributed to a persistent CSF leak at the site of the fracturedislocation which was managed with a percutaneous blood patch.

Conclusions
In conclusion, cervical spine fractures remain a devastating injury, especially when associated with dislocations, however, the timing of intervention and mode of intervention can drastically change the outcome; the return to complete function is a good possibility with adequate surgical decompression and stabilization of the spine.

Additional Information Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.