Spinal cord injury (SCI) accounts for multispectral neurological deficits and severely affects the dichotomous utilization of health resources, especially in low and middle-income nations.[1]
Nearly 80% of the victims are males, with almost 60% of them falling within the age group of 16 to 30 years. Moreover, as high as 60% of them are left unemployed following the incidents.[1]
Subluxation is an important entity of traumatic subaxial cervical spinal injuries. There is a varying degree of slippage of the body of one vertebra relative to the adjacent vertebra, owing to ligamentous injury and the jumped facets, with therefore a high predisposition for injury to the spinal cord.
Road traffic accidents have been mostly implicated in the majority of cases of cervical subluxations.[2] One study found motor vehicle collisions accountable in 51% of such cases, followed by fall-related injuries in 41% such cohort study.[1]
The acceleration/deceleration injury and the direct impact at the neck account for such subluxation.[3]
The traumatic subluxations accounted for 73/163 (44.78%) of cases among the cervical spinal injuries in a single tertiary care center.[1] Most of these patients had Meyerding Type 1 subluxation (35.6%) and presented with the neurological status of the American Spinal Injury Association (ASIA) 'D' category. The most common location for the subluxation was at the C4/5 (28.76%) level.[1]
There is the interplay of various dynamic movements that can lead to multispectral patterns of associated injuries in conjunction with the cervical subluxations. The Allen and Ferguson classification system have categorized the principle loading forces with the resultant spinal injuries as[4]:
The principal mechanics behind the bilateral jumped facets include the hyperflexion injury in addition to the axial loading and the anterior shear.[5]
The management of such patients begins with the assessment of the airway, breathing, and circulation.
The neck of the patient should be immobilized with the application of hard collar to prevent further neurological deterioration from inadvertent neck movements during evaluation and transport.[6]
The primary and secondary survey needs to take place out to rule out potential evidence of polytrauma.
The neurological assessment of the patient needs to be done and documented as per the ASIA grading.[7] A quick localization of the lesion is necessary by assessing the pattern of motor weaknesses (quadriparesis vs. quadriplegic vs. central cord syndrome), level of motor weakness (C5- shoulder shrugging, C6- elbow flexion, C7- elbow extension, T1-hand grip), level of areflexia (at the level of injury), single breath count in the patient (phrenic nerve involvement at C3-4-5 level), and the presence of concurrent Horner syndrome (C7-T1).
After hemodynamic stabilization of the patient, the level, pattern, grade, associated bony ligamentous and vascular injuries, and the pattern of cervical cord injuries require evaluation through a series of radiological imaging. The algorithmic approach to be taken for radiological assessment of the injury is as follows:
The locked facets will show specific findings in radio imaging. The overlap of more than 50% between the articulating surface of the facet joints is considered unstable.[6] The 'bow-tie' sign or the 'batwing' sign is characteristic of a unilateral jumped facet joint.[9] The CT scan specifically shows a reverse hamburger bun sign highly indicative of a facet dislocation.[10]
Various scoring systems have been developed for the classification of patients with cervical spine injuries. The subaxial cervical spine injury classification system encompasses[11]:
The AO Spine subaxial cervical spine injury classification system, on the other hand, categorizes injury depending on[12]:
The AO Spine classification system seems to be of paramount importance in managing patients with traumatic subluxations owing to its importance to the status of the facet joints, the pivotal factor determining the stability of the spine. The damage to the facet joints, therefore, provide a firm rationale for undertaking global fixation of the traumatic spine in a neurologically preserved patients.[12]
Regarding the flexion-distraction pattern of injury that plays a central role in traumatic subluxations, the injuries categorize based on the severity of the injury as[13]:
The nondisplaced facet fracture or minimal diastasis of < 1mm can be managed with an orthosis. However, facet displacement and the concurrent ligamentous injury warrants surgical fixation.[13]
The initial aspects in management deals with the judicious application of cervical traction that helps in
Care always needs to avoid traction of the cord due to heavy tractional weights.[1]
In cases with locked facets, the clinician should attempt a closed reduction under anesthesia, which is successful in almost 95% of cases.[14]
If there is no reduction and the preoperative MR images show the presence of disc prolapse, an anterior approach is a next step, with discectomy followed by open reduction with the aid of Casper distractor. The reduction can then take place by anterior only fusion. The failure of reduction needs the posterior reduction of the jumped facets, followed by 360-degree global fixations in neurologically preserved patients.[14]
The surgical plan in the management of the patient then varies accordingly as per the Meyerding grading and the ASIA neurological status, and the relevant scoring system of the patient.[1][12] The treatment algorithm is also determined by the patient's characteristics as well as the expertise of the team. The anterior approach is better suited to deal with the herniated disc, whereas the posterior approach helps in restoring the posterior tension band as well.[13]
If there is a good reduction following traction, the patients can receive an anterior approach with discectomy or median corpectomy followed by in-situ bony graft fusion or the usage of allograft spacers aided with plate and screw fixations.[1][13]
Sometimes, owing to financial barriers, simple graft placement can also be undertaken. In cases of failed reduction from traction, the clinician can attempt reduction following muscle relaxation after induction of anesthesia. If reduction still fails in patients with ASIA 'A' and 'B' status, posterior-only fixation by interspinous wiring is justified for anatomical fixation as to aid in early rehabilitation.[1] However, in patients with ASIA 'C' and 'D' status, the posterior approach is necessary to first to unlocking the jammed facet, and the anatomical fixation is carried out following lateral mass and translaminar screw and rod fixation.[1] This approach can be reinforced with fixation from the anterior approach as well. However, in neurologically stable patients, if there is significant disc prolapse, discectomy or corpectomy is carried out (to prevent cord injury when the patient is in the prone position), then the posterior approach to unlock the facets and posterior instrumentation is the appropriate procedure, followed again by the anterior approach to bony graft placement along with plate and screw fixation (360-degrees approach) is warranted.[15]
With regards to the AO Spine scale system, the recommended plan of management includes[13]:
The asymptomatic vertebral artery injury has not shown to hinder the operative management of the subluxations. The use of aspirin is recommended in the post-operative period. There is still no shared consensus for managing symptomatic vertebral artery injuries associated with traumatic cervical spine subluxations.[13][14]
Pseudo-subluxation associate with an absent cervical pedicle.[16]
The subluxation of the cervical spine and the associated complications can have negative impacts on patients’ functionality and their quality of life.[17] Most of the patients with poor neurological status are dependent upon their care-providers even for their activities of daily living.
There is a high risk of the need for repeated admissions owing to varied complications in these cohort groups and has shown to be as high as 27.5% in one study.[18]
Hospital-acquired pneumonia and pressure ulcers harbinger disability and lurk mortality, most often in subsets of patients with ASIA grades of A, B, and C.[19]
The complications can be categorized[1][2]:
There need to be provisions for:
The pivotal basis in managing patients with traumatic subluxation is three-fold:
However, in patients with severe deficits, the caretakers have to look after them even for their activities of daily living. The management plan should, therefore, be targeted, focusing on the patient and the care provider together as a unit.
There were no significant differences observed between approaches taken for the anatomical stabilization (anterior-only, posterior-only, and 360-degrees) with the pattern of ASIA recovery seen among the patients.[2]
The prime goals in managing these patients are early anatomical fixation with spinal decompression, followed by the strategies to survive, revive, and thrive these cohorts of patients through:
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