Spinal Dislocations Treatment & Management

The usual indications for surgical reconstruction include loss of mechanical stability and neurologic compromise. With the high incidence of neurologic deficits associated with dislocation fractures, surgical management remains a primary tool for the recovery of these patients. Because all three columns of the spine are involved, reconstruction may include an anterior or a posterior approach. Not infrequently, both approaches may be necessary to maximize neurologic recovery and to reestablish spinal column integrity.

If the neurologic deficit is complete with return of reflex function, recovery is unlikely, and surgery is performed to expedite rehabilitation. When the injury results in an incomplete deficit that is progressing, urgent decompression and stabilization are indicated to halt progressive neurologic loss and to hasten recovery.

Care should be taken in positioning the patient with a thoracolumbar dislocation. It has been demonstrated that supine positioning further narrows an already compromised spinal canal. Turning the patient to a lateral position with the spine slightly flexed may improve function in an incomplete injury. Attempts at closed reduction are usually unsuccessful with these injuries, and operative intervention is necessary for definitive reduction and stabilization.

Contraindications for surgical treatment are few. Surgery is contraindicated in patients on warfarin or other anticoagulants. In these patients, reversal of the anticoagulated state is required befpre the operative procedure. Surgery may be contraindicated in patients with medical conditions such as acute myocardial infarction.

Treatment methods have evolved over the past 50 years, and means of minimizing the extent of injury are employed. Such treatment has included the acute administration of high-dose steroids on the basis of the results of three studies published by the National Acute Spinal Cord Injury Study (NASCIS), as well as the use of gangliosides as reported by Geisler et al. ^{[20, 21, 22, 23, 24, 25, 26]}

Timely canal decompression and stabilization of the affected areas have been made possible by the introduction of modern instrumentation systems and improved surgical approaches. Research continues to address spinal-cord recovery and has included laboratory experiments in neural element transplantation and fetal cell transplants. Firm supportive data for these efforts remain to be obtained in a clinical setting; however, research must continue in order to aid this growing population of patients.

Fracture dislocations are associated with the highest incidence of neurologic injury. In individuals with incomplete or normal neurologic examination findings, the spinal injury has still resulted in significant instability. To allow early mobilization and afford the chance for neurologic improvement, surgical management is almost always indicated. Closed reduction of these injuries is quite difficult, if not impossible. Maintenance of the reduction without operative intervention is problematic.

Most often, dislocation fractures can be managed via an entirely posterior approach. Reduction of the malalignment results in spinal-canal clearance in most individuals. Significant residual compression can be addressed through an anterior approach either in a staged manner or on the same day, depending on the circumstances. The posterior instrumentation and fusion allow reestablishment of the tension-band function of this segment of the spine; however, if significant anterior column loss (burst component) exists, anterior reconstruction may be indicated. ^[27]

Daniaux described the use of transpedicular bone grafting. ^{[28, 29]} In this approach, the defect created by the reduction is filled with autologous bone. The graft is intended to fill the anterior half of the body and to avoid posterior extravasation. Arnold suggested a second means of posterior grafting, which involved performing a basal osteotomy of the transverse process and filling the body through a posterolateral window. ^{[30, 31, 32, 33, 34, 35]}

Preparation for surgery

The patient's blood is usually typed and crossmatched, and 2 units of blood are made available preoperatively. In the unusual case of a patient who is neurologically intact, neuromonitoring would be warranted. The anesthesiologist may place an arterial line or may establish central access, depending on the individual patient and any other injuries that may be present. A Foley catheter is inserted to monitor urinary output throughout the procedure.

The patient is placed prone on the operating table, and chest rolls or a Wilson frame may be used after careful logrolling. All bony prominences are padded carefully, and superficial nerves (eg, the ulnar nerve) are protected. The arms are placed on arm boards, and hyperabduction of the shoulders should be avoided.

Operative details

A midline incision extending from one level above to one level below the proposed segments to be instrumented should be used.

Once the incision has been carried down to the tips of the spinous processes, careful subperiosteal dissection should be continued bilaterally to the facet joints. Frequently, much of the dissection has already occurred from the injury, with muscle and soft tissues displaced from the bony elements. A good rule is to start above and below in normal anatomy and work carefully towards the injured zone. Packing with gauze sponges helps tamponade the bleeding, and packing can be replaced as the exposure continues.

The transverse processes are then stripped of overlying muscle until the tips are exposed. Bipolar and unipolar cauteries are used to maintain hemostasis. Because the spinal canal may be open and the dura exposed, care must be taken in approaching this area. The exposed facet joints at the level of dislocation may be denuded of their articular cartilage before reduction.

Frequently, an associated fracture is present. Resection of bone should be avoided at the joint level, because this further destabilizes the spine. Reduction is generally achieved by means of gentle distraction with a lamina spreader and manipulation with bone-holding forceps or towel clips. Once the reduction has been obtained, a single wire or cable may be passed through the adjacent spinous processes before definitive fixation.

At this point, options for fixation include multiple hooks in a claw construct two ro three levels above and one or two levels below. Depending on the individual anatomy, pedicle screw fixation may be used from two segments above to one or two segments below. The landmarks for insertion for pedicle screws in the lumbar spine include bisection of the transverse process as it abuts the superior articular facet. The angle of inclination varies from 10-15° at L1 to 25° at L5.

Thoracic screw insertion is performed 3 mm lateral to the center of the facet joint, just below the articulation. Image intensification, in addition to surface landmarks, may be used in the thoracic region. Intraoperative stereotactic guidance has been used in a number of centers but has not been universally applied. Although a compression construct provides the most rigid stabilization, the risk of disk herniation increases; accordingly, this construct should be used with caution in the patient who is neurologically intact or not.

An autograft may then be harvested from the iliac crest, and decortication for fusion purposes generally is performed for the length of the instrumentation. Studies have demonstrated that instrumented segments that are not formally fused usually undergo ankylosis, and application of the graft may be limited to one segment above the disruption to one segment below. Closure is performed in a layered fashion over a Hemovac drain, which is removed 1-2 days postoperatively.

Postoperatively, the patient should be turned frequently, and thromboembolic prophylaxis should be addressed with compression devices and, in certain instances, medically with either low-molecular-weight heparin (LMWH) or warfarin. In certain cases where anticoagulation is contraindicated (eg, with gastrointestinal ulcers or intracranial injuries) or pulmonary embolism has occurred despite adequate anticoagulation, mechanical vena cava filters may be inserted.

Early mobilization is encouraged, and bracing may not be necessary (depending on the degree of stability obtained during surgery). In a patient who is neurologically intact, close monitoring and early mobilization should minimize skin breakdown.

The Foley catheter should be removed, and intermittent catheterization should be performed as soon as the patient's general medical condition permits. An early bowel regimen should be initiated, and alternate-day suppositories should be used.

Once the patient is medically stable, transfer to a rehabilitation facility with special expertise in spinal injuries is beneficial to the recovery process. In such a facility, the physical and psychological issues facing the individual patient and the family can be addressed in an environment that includes other patients with similar problems.

Complications can be subdivided into two major groups, as follows:

• Complications related to the operative procedure
• Complications secondary to the spinal cord or cauda equina injuries

Surgical complications can be further classified as related to the following:

• Positioning
• Intraoperative occurrences
• Postoperative complications

Patients with spinal injuries should be positioned carefully at the time of surgery to avoid compression of bony prominences. The arms should be placed at right angles to the body or tucked by the sides. The ulnar nerve is particularly vulnerable, and pressure at the elbow should be avoided.

Intraoperative complications include the following:

• Dural tears
• Misdirected instrumentation
• Excessive bleeding necessitating transfusions and fluid replacement

Although the level of injury is usually obvious at the time of surgery, intraoperative imaging can be extremely valuable for documenting the levels of stabilization and the positions of pedicle screws and hooks. Placement of hooks in the thoracic region may compromise canal space; a staggered hook construct, if feasible, avoids excessive canal stenosis at each level. With close attention to the positioning of pedicle screws, malplacement can be avoided. The tip of the screw should not cross the midline on an anteroposterior (AP) radiograph but should generally point toward the midline.

Postoperative attention to adequate resuscitation is of the utmost importance. Frequently, fluid and electrolyte concerns, including serum magnesium replacement, must be addressed. Correction of clotting abnormalities may necessitate the administration of fresh frozen plasma and platelets; however, mild deficits usually correct rapidly in the absence of significant liver abnormalities.

Postoperative hematomas may have to be drained, and persistent drainage should be aggressively managed to avoid an underlying deep infection. The appearance of the skin may be misleading, and certainly, if a spiking temperature occurs in this setting, early exploration is warranted. Unrecognized cerebrospinal fluid leakage may be heralded by postural headaches and clear drainage from the wound. Eismont suggested open operative repair when possible, but the use of closed drainage techniques for 3-5 days has also been recommended to manage this problem. ^[36]

The sutures generally can be removed after approximately 10 days, and rehabilitation can be initiated as soon as the general medical condition of the patient allows.

Arthrodesis progresses over a 3- to 6-month period, and serial radiographs should be obtained to assess the alignment and progressive union of the bone grafting. It is not uncommon to see gradual loss of 10° of correction with posterior-only procedures.

Bracing, usually involving a removable thoracolumbosacral orthosis (TLSO), is employed for 3-6 months. In individuals who are paraplegic, close attention must be paid to skin pressure and potential breakdown.