Lower (Subaxial) Cervical Spine Fractures and Dislocations Treatment & Management

The primary indications for surgical intervention in subaxial cervical injuries include the following:

• Malalignment of the spine, with or without neurologic deficits
• Progressive neurologic deterioration in the face of persistent compression from bone or disk fragments

Although malalignment can be managed initially with cervical tong traction, definitive surgical stabilization, with or without decompression, generally is required.

Anterior-column trauma may result from axial loading injuries in combination with flexion, extension, or rotational moments. Typically, the burst fracture or teardrop variant occurs with translation of bony fragments into the spinal canal. ^{[19, 20, 21]}  Direct trauma to the cord may result in incomplete or complete spinal cord injury (SCI) syndromes. Most frequently, anterior SCI is accompanied by loss of motor function and pain and temperature sensations, along with preservation of proprioception and vibratory sensation.

Central cord syndrome refers to the clinical picture of greater upper-extremity involvement than lower-extremity motor deficits. Return of function follows a distinct pattern of lower-extremity improvement, followed by upper proximal muscle improvement, followed finally by distal upper-extremity function, which may recover incompletely. Brown-Séquard syndrome is typically a hemisection of the spinal cord, with loss of ipsilateral motor function below the level of involvement; contralateral pain; and temperature loss. This is generally seen with penetrating injuries (eg, gunshot wounds).

Posterior injury may result in unilateral or bilateral facet fracture, dislocation, or both. Isolated spinous process injury is usually a stable injury and does not require surgical attention. Unilateral facet dislocations may be the most difficult to reduce by closed means, and open reduction and stabilization are often necessary. ^[22]  Radiculopathies with or without cord damage may be seen with the unilateral facet injury and are commonly considered an indication for surgery. ^[23] Bilateral facet dislocations have the highest incidence of SCI, with both incomplete and complete syndromes appearing.

Reduction of subaxial malalignment must be undertaken with caution in the presence of certain concomitant disk herniations. Those that displace posteriorly and inferiorly have been reported to cause worsening neurologic deficits with both open and closed reductions. In the awake and cooperative patient, it is possible to carry out cautious reduction while performing serial neurologic examinations. In the case of intoxication or closed head injury, in which examination may be impeded, magnetic resonance imaging (MRI) may prove prudent to avoid catastrophic neurologic injury.

If such a disk herniation is identified before reduction, it can be removed anteriorly, and reduction then can be performed safely. This has been described in both unilateral and bilateral facet dislocations.

Guidelines on treatment of subaxial cervical spine injuries are available from the Congress of Neurological Surgeons (see Guidelines). ^[24] Guidelines on treatment of spine injuries in general are available from the American College of Surgeons. ^[25]

Medical management involves treating the multiple traumas and, more specifically, treating concomitant neurologic injury. The use of steroids for neurologic injury has become standard to prevent secondary causes of spinal cord damage, such as release of toxic peroxidases, and to minimize associated local edema. Steroids are thought to help stabilize neural membranes, to prevent uncontrolled intracellular calcium influx, to decrease lysosomal enzyme action, and to diminish swelling and inflammation.

In three National Acute Spinal Cord Injury Study (NASCIS) reports, the recommended management for patients with SCI presenting within 3 hours of injury was a 30 mg/kg loading dose of methylprednisolone given intravenously (IV) over 1 hour, followed by 5.4 mg/kg/hr for the next 23 hours. If the patient presents more than 3 hours but less than 8 hours post injury, the 5.4 mg/kg/hr dosage is extended for 48 hours following the same loading dose. Steroid treatment does not seem to be beneficial if begun more than 8 hours post injury or after nerve root trauma. ^{[26, 27, 28, 29]}

The Spine Focus Panel, in a 2001 review of the literature, continued to recommend the steroid protocol on the basis of its modest neuroprotective effects, its favorable risk-to-benefit ratio, and the lack of alternative therapies. However, the use of steroids in penetrating injuries, especially gunshot wounds, has not proved beneficial. ^[30]

The use of steroids has been questioned because of its risk-to-benefit ratio. Complications, including increased risk of infection, stress ulcers, hyperglycemia, and compromised healing of surgical and other wounds, have prompted many clinicians to avoid steroids in the case of SCI. A committee of neurosurgeons, orthopedic surgeons, emergency physicians, and physiatrists, at the request of the Canadian Spine Society and the Canadian Neurosurgical Society, concluded the following ^{[31, 32]} :

• There is insufficient evidence to support the use of high-dose methylprednisolone within 8 hours following acute closed SCI as a standard or as a guideline for treatment
• Methylprednisolone prescribed as a bolus IV infusion of 30 mg/kg of body weight over 15 minutes within 8 hours of acute closed SCI, followed 45 minutes later by an infusion of 5.4 mg/kg of body weight per hour for 23 hours, is a treatment option for which there is weak clinical evidence.(level II, III)
• There is insufficient evidence to support extending methylprednisolone infusion beyond 23 hours if this is chosen as a treatment option

These recommendations were presented to the two sponsoring societies and adopted.

Prospective studies also assessed the effect of lazaroids and gangliosides on ultimate neurologic outcome, without documenting any significant lasting effects. The effectiveness of these agents was shown in the mild and partial injury groups, not in complete SCI. ^[33] Other modalities of treatment have included hypothermia, calcium-channel blockers, and naloxone, but these treatments have failed to show helpful effects.

The use of histamine-2 (H2) blockers (eg, famotidine and ranitidine) generally is recommended to prevent stress ulceration from SCI and for prophylaxis when the steroid protocols are followed.

Prophylaxis for deep vein thrombosis (DVT) and pulmonary embolism is of particular concern in the neurologically compromised patient. Rates for DVT in complete injuries range from 30% to 90%; DVT warrants medical and/or mechanical treatment. This may include low-molecular-weight heparin (LMWH), oral warfarin, intermittent compression devices for the lower extremities, or vena cava filters.

Experimental therapies

Restoration of spinal cord function after injury remains a major challenge to those treating paralyzed victims. Although prevention and treatment of secondary cord damage continues to be a primary objective, the ability to reverse established cord dysfunction is a major goal. Attempts to reestablish neural recovery have focused on modification of the injured tissue through implantation of acellular guiding prosthesis, fetal tissue, and glial cells.

The activation of intrinsic neural capacities through gene therapy or by delivering a host of neurotropic substances such as nerve growth factor or brain-derived neurotrophic factors is being explored experimentally. The use of stem cells and trials using olfactory glial cells remain on the horizon. Olfactory glial cells are the only neurons able to replicate in adult life. They are capable of crossing scar tissue as well as bridging the gap between the peripheral nervous system and the central nervous system (CNS).

Potassium channel blockade has been used in the clinical arena and has been successful in helping as many as one third of patients with chronic SCIs. The drug 4-aminopyridine has been most effective in patients with incomplete SCIs. ^[34]  It is believed to work through blockage of the fast A-type potassium channels that increase the safety factor of conduction across demyelinated or thinly remyelinated internodes or by increasing influx of calcium at presynaptic terminals, which improves neural transmission.

Initial surgical management focuses on the specific injury encountered. Such injuries may be classified into the following three categories:

• Those involving primarily the anterior column or vertebral body
• Those involving the posterior column with pedicle, facet, or lamina injury
• Those involving both columns

Spinal realignment generally is emphasized. This begins with the application of cervical tongs and continues by serially increasing traction until normal spinal alignment is achieved and bony compression is reduced. (See the image below.) Gardner-Wells tongs have been the criterion standard for years because they are easy to apply and can withstand great weight until reduction is obtained. Tongs or halos compatible with magnetic resonance imaging (MRI) can also be used and have the advantage of allowing urgent MRI when appropriate.

If the injury primarily involves the anterior column, a Smith-Robinson or standard anterior approach to the spine is used to allow anterior decompression and reconstruction with either allograft or autograft iliac crest or fibula, followed by stabilization with anterior locking plates.

In a study of 33 patients who underwent surgical treatment for traumatic subaxial cervical spine fractures with discoligamentous injuries, Lang et al found that dynamic anterior plate fixation yielded results comparable to those of rigid locking plates. ^[35]

The posterior approach is indicated when the pathoanatomy involves the posterior elements and is the basic midline approach with muscle retraction off the cervical spine to the lateral aspect of the facet joints bilaterally.

Occasionally, a dual approach is necessary to remove an offending disk fragment anteriorly prior to reduction, followed by posterior stabilization with anterior reconstruction. These global injuries are usually quite unstable, and they have been found to benefit from both anterior and posterior reconstruction. ^[36]

Lee et al, in a meta-analysis of eight biomechanical and four clinical studies comparing anterior-only with combined anterior-posterior fusion for unstable subaxial cervical injuries, ^[37]  found that combined fusion provided better biomechanical stability for unstable cervical injuries than anterior-only fusion; however, there were no significant differences in clinical outcomes. They therefore recommended selective use of anterior-only or combined fusion for unstable cervical injuries according to the type of injury present, rather than routine use of combined fusion.

Preparation for surgery

In-hospital care of the patient with a cervical spine injury should be meticulous in the preoperative period. These patients are at risk for pulmonary problems secondary to concomitant injuries and to immobilization. Gastrointestinal (GI) bleeding has been reported in as many as 40% of patients and is most common around 10 days following injury. This can be aggravated by corticosteroid use and can be treated with H2 blockers and early enteral feedings.

These patients are also at risk for developing DVT secondary to immobilization. The incidence of DVT has been reported to be as high as 95%, and DVTs are clinically relevant in as many as 35% of people. Some form of anticoagulation and compression boots should be used. Skin breakdown due to immobilization is also a problem and should be treated aggressively with pressure relief and wound care.

Timing of surgical intervention

The above preoperative problems and their association with immobilization have contributed to controversy in the timing of surgical intervention. Proponents exist for both early and late surgical intervention. ^[38]  Some studies showed worsening after surgical intervention within the first 5 days after injury. These studies reported increased mortality and neurologic deterioration, concluding that a 1-2 week delay in operative intervention is best. However, other studies showed that neurologic damage is affected not only by the degree of cord compression but also by its duration. These studies led to recommendations for urgent decompression.

Most surgeons now advocate early intervention, recognizing that patients are better candidates for surgery in this early window of opportunity before other complications occur. The best reasons for early surgical intervention are to avoid preoperative systemic problems, to provide rapid decompression of the injured cord, and to return to mobilization. One other important scenario is in the patient who exhibits progressive neurologic worsening: In such patients, it is generally agreed that prompt surgical decompression is absolutely necessary.

A critical review of the literature regarding preclinical and clinical evidence on the potential impact of timing of surgical decompression after traumatic SCI included 153 abstracts, of which 22 fulfilled the inclusion and exclusion criteria. The vast majority were level 4 evidence; two were level 2b. The most common definition of early surgery was 24-72 hours following SCI.

An expert panel recommended that early surgical intervention be considered from 8 to 24 hours following acute SCI. In accordance with a modified Delphi process, the following recommendations were made ^{[39, 40]} :

• There is strong preclinical evidence for the biologic benefits of early surgical decompression in animal SCI models
• Decompression should be performed within 24 hours when medically feasible; the optimal timing of surgical decompression, as well as whether surgery is indicated at all in patients with central cord syndrome injury, remains unclear
• Early spinal cord decompression has clinical, neurologic, and functional benefits

A single-center prospective cohort study by Du et al evaluated 402 patients with traumatic cervical SCIs (C3-7) who underwent decompression surgery of the spinal cord either early (< 72 hr after injury; n = 187) or late (≥ 72 hr after injury; n = 215). ^[41] Each group was divided into A0, A1-4, B, C/F4 and F1-3 subgroups on the basis of the AOSpine subaxial cervical spine injury classification system. The investigators found that whereas aggressive early decompression was not required for type A and F1-3 fractures, type B and type C/F4 fractures should receive early surgical treatment for better clinical outcomes.

Operative details

When the patient is taken to the operating room, certain issues must be addressed. If the patient has been in traction or a halo for reduction of the spine, this must be maintained in the transfer to the operating table and while the patient is on the operating table. This sometimes requires an awake patient, nasal intubation, or both with meticulous handling of the cervical spine during the entire process. Thus, the surgeon, anesthesiologist, and nursing staff must all be working in concert to ensure the patient's safety.

The operative approach obviously dictates whether the patient is prone or supine, and in some instances, both positions are needed for the combined approach. Whatever position is used, the hips, knees, shoulders, hands, and feet should all be well padded to prevent pressure sores and peripheral nerve palsies. The Stryker frame and Jackson frame are operating beds designed with a pulley to facilitate traction of the cervical spine. They also are designed with removable pads for patient positioning, and some are equipped with a turning frame to allow the patient to be spun safely from the supine to the prone position and back.

The indications for spinal cord monitoring are also somewhat controversial among surgeons. Somatosensory evoked potentials (SSEPs) offer a safe, noninvasive, and continuous technique for assessing the functional integrity of the spinal cord. Several reports suggested that changes in evoked potentials are predictive of neurologic change in the patient. When a signal deformity is detected, it can be checked with a wake-up test to ensure its accuracy. However, the delayed nature of the change makes these tests of limited efficacy in preventing intraoperative injury.

A major problem with the technique is that multiple false-positive and false-negative results have been reported. In addition, monitoring is only as good as the skill of the personnel performing it. In summary, SSEPs and motor-evoked potentials (MEPs) may have some benefit in the neurologically intact patient in whom significant intraoperative manipulation of the spinal column is anticipated.

Postoperatively, patients usually are maintained in some sort of cervical orthosis, depending on the quality of fixation obtained. Fixation techniques have improved dramatically in recent years. Before, most patients were placed in a halo postoperatively; now, patients are placed in only a rigid or soft collar for comfort.

The patient should be mobilized out of bed as soon as possible to prevent pulmonary and thromboembolic complications. A return to independence should be approached aggressively, with the help of a comprehensive team that includes a physical therapist, social service personnel, and family. In patients with SCI and neurologic deficit, extensive physical and emotional rehabilitation should be instituted immediately following surgery to ensure the best physical and psychological outcome for the future. ^[42]  (See the images below.)

Postoperative management of bowel and bladder dysfunction should include instruction in intermittent catheterizations, as well as the use of alternate-day suppositories and a high-fiber diet to assist with bowel function and avoid impaction.

Close attention to skin breakdown should include frequent turning of the patient and, as mentioned above, prompt mobilization.

Complications secondary to lower cervical spine fractures and dislocations can be divided into the following two major categories:

• Fracture-dislocation–associated problems
• SCI or medical-related problems, including pulmonary problems (eg, pneumonia, atelectasis, pulmonary embolus), GI problems (eg, stress ulcers), urologic problems, skin problems (eg, pressure injuries), DVT, and psychological problems (eg, depression)

Autonomic dysreflexia is a syndrome of generalized sympathetic discharge resulting in severe headache, nausea, chills, anxiety, and sweating. Blood pressure may become dangerously high, usually as a result of bladder distention or fecal impaction. Prompt removal of the inciting stimulus and treatment of the high blood pressure are emergency measures necessary to avoid catastrophic stroke. This is a potentially lethal condition if unrecognized.

Failure to achieve realignment of the spine is among the first problems that can be encountered in dealing with this group of injuries. Whereas reduction of bilateral facet dislocations tends to be accomplished easily with cervical tongs and traction, unilateral jumped facets may be more problematic. If a reasonable attempt at reduction has been performed (50 lb [~23 kg]) or neurologic deficit is persistent or worsening, open reduction and stabilization usually can be accomplished via a posterior approach.

A unilateral root injury is more typical with these injuries. Simple inline traction does not address the rotational component of this injury, and a manipulative reduction with the patient awake can be performed once sufficient traction and flexion have disengaged the locked facet. Closed reductions are successful in about 50% of cases; the remainder require open reduction, which can be achieved easily by grasping the spinous processes and lifting and rotating the facet into place.

Because unreduced dislocations are associated with a high incidence of instability, pain, and stiffness, reduction should be performed by either closed or open means. Simple wiring or lateral mass plate fixation can maintain stability while healing occurs. Supplementing the fixation with bone grafting for arthrodesis does not always seem to be necessary, as pointed out by Levine and Roy-Camille, with plating techniques. ^[43]

Patients must be monitored closely for the first 4 weeks postoperatively to ensure maintenance of spinal alignment and confirm that there is no evidence of neurologic deterioration. Independence should be encouraged, and attempts to regain preinjury activity levels should begin.

Between 2 and 3 months of healing usually is expected, and radiographic signs of osseous healing should be noted in this time frame. Some patients may require up to 6 months to achieve preinjury activity levels; others, based on concomitant injuries and age, may never reach this status. Aggressive therapy should continue during this entire period. Once the injury is healed and the patient is functioning at maximal levels, return to full activity is begun.

During the follow-up period, any deterioration in neurologic function should prompt further investigation, including MRI for posttraumatic syrinx or other intrinsic or extrinsic compressive lesions.