Lumbar Spine Fractures and Dislocations Treatment & Management

The decision whether to perform surgery in the acute setting is made by the surgeon, depending on the stability of the fracture, the radiologic evidence of spinal cord or cauda equina compression, the patient's neurologic examination, and the overall status of the patient. In general, decompressive surgery is not indicated for patients with complete deficit lasting more than 48 hours and is advocated for patients with partial cord or cauda equina injuries.

The relation between the timing of surgical decompression and the neurologic outcome has been widely debated. Some evidence in the literature suggests that acute surgical therapy decreases the length of hospitalization and related costs, facilitating rehabilitation in many patients with spine injury.

Numerous factors must be considered in the selection of the surgical approach, including the degree of bone destruction, associated ligamentous injury, presence and degree of neurologic deficit, age and medical condition of the patient, and other associated injuries.

With regard to potential future therapeutic developments, the use of growth factors for the induction of spinal fusions is an attractive approach. Some studies have shown that viral vectors can be used to implant osteoinductive growth factor genes directly into the paraspinal muscles or into cells that can be subsequently implanted next to the spine. These osteoinductive factors enhance the activation and differentiation of pluripotent stem cells to produce mature bone.

Numerous studies support the view that morphogenic bone proteins (ie, bone morphogenetic protein type 2 [BMP-2] and other polypeptides, such as transforming growth factor beta), acidic and basic fibroblast growth factors (FGFs), insulinlike growth factors (IGFs), and platelet-derived growth factors (PDGFs) are effective in promoting bone formation and fusion. Studies using BMP-2 have demonstrated the same rate of fusion reported in studies using autologous iliac crest bone graft, avoiding the morbidity of harvesting iliac crest bone. ^[2] However, the high cost of this therapy limits its widespread use.

Studies are being performed on a variety of proteins with a range of physiologic activities in the growth and development of numerous organ systems, including the heart, liver, skeleton, tendons, ligaments, and skin. Their use in humans is currently under investigation.

Guidelines for the treatment of lumbar and thoracic fractures have been developed by the American Association of Neurological Surgeons (AANS)/Congress of Neurological Surgeons (CNS) Section on Disorders of the Spine and Peripheral Nerves and the Section on Neurotrauma and Critical Care workgroup. ^{[29, 30, 31, 32, 33]}  Guidelines for the management of spine injuries in general have been published by the American College of Surgeons (ACS). ^[34] (See Guidelines.)

Initial management of lumbar spine injury begins in the field. Any patient in whom a spinal injury is suspected should be placed on a board in a neutral supine position and immobilized in a neck collar for expeditious transportation to a trauma center. ^[35]

In the emergency department, all patients should be treated as though they have a spinal injury until spinal injury can be ruled out. The Advanced Trauma Life Support (ATLS) guidelines of the ACS should be followed. Stabilization of the patient's airway and hemodynamic status should precede any treatment in order to secure adequate oxygenation and tissue perfusion. A Foley catheter should be inserted. In patients with neurologic deficit, immediate peritoneal lavage often is advocated to rule out intra-abdominal injuries. ^{[36, 37]}

Once the patient has been resuscitated, plain films of the cervical, thoracic, and lumbosacral spine should be obtained.

When possible, a detailed history should be obtained to ascertain the mechanism of injury and the relative force sustained.

Individuals who sustain falls often have hyperflexion injuries at the thoracolumbar region in association with pelvic and lower-extremity fractures.

Persons who wore seat belts during motor vehicle accidents often have distraction injuries or associated cervical spine injuries. In these patients, the vertebrae frequently are compressed or dislocated in the horizontal plane. Crawford et al ^[38] studied the surgical management of pediatric patients with seat-belt fracture-dislocations of the spine.

Head injuries and extremity fractures commonly accompany vertebral fractures. Abdominal or urologic trauma can occur with lumbar fractures, particularly with motor vehicle–type injuries. ^{[7, 39]} The possible presence of concurrent direct injuries to adjacent intracavitary soft-tissue structures (eg, renal, spleen, or liver lacerations) must be considered.

In general, the more caudal the vertebral injury, the greater the biomechanical forces sustained and the greater the propensity for injuries to the pelvis and sacrum.

As early as possible and within 8 hours following injury, all patients with spinal cord injuries (SCIs) should receive intravenous (IV) methylprednisolone at 30 mg/kg in a bolus, followed by infusion at a rate of 5.4 mg/kg/hr for 23 hours. The results of a prospective trial demonstrated significantly better motor function and sensation at 6 months and 1 year in patients treated with this regimen compared with those given placebo.

The major goal of treatment in patients with disruption of the vertebral column who are neurologically intact is the prevention of neurologic deterioration. If a fracture is stable without nerve compression, surgical treatment may not be required. When a fracture is unstable or when neural compression is present, a decompressive procedure with a fusion, usually with instrumentation, becomes necessary. Stabilization is aimed at minimizing pain and subsequent spinal deformity.

Compression fractures have a disrupted anterior and intact middle column. Treatment of these injuries depends on the status of the posterior ligamentous structures, as well as on the integrity of the bony elements. Compression of more than 40% of the anterior vertebral wall or a kyphotic deformity of more than 25° is often associated with posterior ligamentous injury. If the kyphotic angulation is less than 25° and the anterior body compression is less than 40% of the vertebral height, the injury can be treated nonoperatively.

The patient is placed in a thoracolumbar orthosis (TLSO) with restriction of activities. ^[40] After 3-4 months in the orthosis, flexion extension radiographs should be obtained.

If no motion is present and the deformity has not progressed, the patient can be weaned from the TLSO over several weeks and can start physical therapy for muscle strengthening. If abnormal motion is present, the deformity has progressed, or severe pain persists, surgical stabilization may be required. If the anterior column is compressed more than 40% or the kyphosis exceeds 25°, surgical stabilization is indicated.

In burst fractures, both the anterior and the middle column are disrupted ^{[41, 42]} ; the posterior column may or may not be affected. In burst fractures, it is important to analyze the percentage of canal compromise, the degree of angulation, and the neurologic status of the patient. ^[43] If the canal compromise is less than 40%, the patient may require a TLSO brace worn for at least 3 months. Standing lateral radiographs should be obtained on a regular basis to document any interval increase in spinal deformity.

If the canal compromise is more than 40%, the kyphotic deformity is more than 25°, or the patient develops neurologic changes (eg, changes in motor function or bladder control, new sensory deficits), surgical intervention may be required. Burst fractures can be reduced and stabilized from an anterior or a posterior approach. ^{[44, 45]} In patients with burst fractures and significant posterior column disruption, anterior and posterior fusion (360°) is indicated. ^{[46, 47]}

In patients with fracture-dislocation injuries, all three columns of the spine are disrupted. This type of injury carries a high incidence of SCI. In general, most fracture-dislocation injuries require surgical treatment. If a patient with a fracture-dislocation has normal neurologic examination findings, the spine must be stabilized to prevent a spinal cord, cauda equina, or nerve root injury.

When the patient has an incomplete SCI from a fracture-dislocation, the spinal canal should be decompressed and the spine stabilized to prevent neurologic deterioration. Stabilization of the spine in patients with a complete neurologic deficit from a fracture-dislocation may prevent progressive kyphotic deformation, allowing early mobilization and rehabilitation, thereby minimizing the hospital length of stay.

Indications for surgery

Surgical intervention is often necessary for patients with unstable fractures or those with neurologic deficits related to compression of the neural structures by bony elements or hematomas, partial cord injuries, or cauda equina injuries. In patients with fractures and associated SCI, the efficacy of decompressive surgery varies according on the level and degree of injury. ^{[48, 49]}

In general, if a patient has a complete neurologic deficit (paraplegia or tetraplegia) and the neurologic examination findings do not improve within 48 hours, decompressive surgery is not indicated, because it will not produce an improvement in neurologic function.

Patients with cauda equina or incomplete cord lesions, however, have been shown to benefit from decompressive surgery even after long delays. Some studies have failed to demonstrate a correlation between the degree of canal compromise at the thoracolumbar junction and neurologic deficits. In contrast with patients with SCIs at the cervical and thoracic spine, patients with nerve root compression at the lumbosacral region often achieve better outcomes following surgical decompression.

The effect of the timing of decompressive surgery on the rate of neurologic recovery also has remained unclear. ^{[50, 51]} Improved neurologic function has been reported with early and late decompression. Most studies have reported on the neurologic recovery associated with late anterior decompression and have not directly analyzed the significance of the timing of surgery. Several studies showed that early spine fixation (≤48 hours) reduced morbidity and resource utilization. ^[52]

There appears to be a trend toward early surgical intervention in patients with spinal instability or neurologic deficits resulting from compression of the neural structures.

Various operative techniques are used in the treatment of spinal trauma. The surgical approach used is determined by the following factors:

• Level of injury
• Characteristics of the fracture
• Location of the neural compression

Modern surgical techniques allow effective decompression of the neural structures via microsurgical approaches. In patients with unstable fractures, the use of segmental instrumental fixation is often necessary in conjunction with a fusion of the spine, via either an anterior or posterior surgical approach. This allows reduction and stabilization of the injured segments.

Regardless of the type of instrumentation and surgical approach, a fusion in conjunction with the segmental fixation is of paramount importance because any type of instrumentation will fail if the spine is not supported by a solid bony fusion.

Surgery is contraindicated in moribund patients in very poor medical condition.

Clinical practice guidelines regarding the management of burst fractures were published by the Congress of Neurological Surgeons in 2018 (see Guidelines). ^[33]

Preparation for surgery

The surgical procedure usually is performed with the patient under general anesthesia in a prone, lateral, or knee-elbow position. Once general anesthesia has been induced and the endotracheal tube secured, the patient's eyes should be well lubricated and taped shut. For a posterior approach, the author's preference is to perform the procedure with the patient under general anesthesia in the prone position over gel rolls that extend from the shoulders to the lower pelvis; alternatively, a Wilson frame may be used.

The use of a radiolucent Wilson frame on a Jackson table is recommended because it maintains the spine in lordosis and avoids increased intra-abdominal pressure. Increase in intra-abdominal pressure increases venous pressure to the epidural veins, resulting in increased epidural bleeding.

The use of intraoperative spinal cord monitoring of the somatosensory evoked potential (SSEP) and electromyography (EMG) is recommended to minimize the risk of further neurologic deficits.

The authors prefer the use of the operative microscope, which allows increased illumination and visibility.

Surgical decompression

The preferred posterior skin incision is a midline one. The length of the incision should permit complete visualization of the entire hemilamina rostral and caudad to the appropriate interlaminar space or spaces, as well as the entire facet complex.

The lumbodorsal fascia is incised with the electric knife just lateral to the spinous process and supraspinous ligament. Atraumatic dissection of the muscles off the spinous processes, laminae, and transverse processes is accomplished with a periosteal elevator and electric knife. After exposure of the appropriate interlaminar area, a self-retaining retractor is used to retract the musculofascial layers. Posterior element fractures usually are visualized at this time.

If compression of neural structures has been determined preoperatively, adequate bilateral exposure and decompression of ligaments and bone are then performed with a high-speed drill, rongeurs, and Kerrison punches and carried both rostrad and caudad well beyond the area of neurocompressive pathology. All residual ligamentum flavum is gently microdissected from the dura and nerve root sheath and excised with either a 2- or 3-mm thin-footplate Kerrison rongeur.

Once adequate dorsolateral decompression and exposure of the dural sac and involved nerve root have been accomplished, a generous foraminotomy is accomplished with the thin-plate Kerrison rongeur.

Posterior intertransverse fusion

The spine is exposed through a posterior midline incision and subperiosteal muscle dissection. The incision length must be sufficient to enable full exposure of the transverse processes. The dissection is carried out laterally over the facet joint to expose the transverse processes completely at the levels to be fused. All soft tissue is meticulously removed from the grafting area, including the transverse process, the lateral aspect of the superior facet joints, and the pars interarticularis.

The bone graft can be harvested either through the previously made midline incision or through the separately placed lateral incision. The superior and outer margins of the iliac crest are exposed subperiosteally. Multiple corticocancellous strips are harvested.

After adequate bone harvest, the donor bed is copiously irrigated with antibiotic solution and waxed to reduce blood loss. This wound is closed in layers. Decortication of the graft bed usually is performed with a high-speed drill. The harvested bone then is placed onto the recipient bone bed and packed into the facet joints. The wound is copiously irrigated and closed with an absorbable suture.

The intertransverse process region provides ample surface area for graft contact, which results in a high rate of fusion. Exposure of this region requires substantial paraspinal muscle dissection, which can be bloody and time-consuming. This technique does not decrease immediate motion, correct deformity, or maintain spinal alignment and generally is used in conjunction with pedicle screw placement.

Posterior interbody fusion

Lumbar interbody fusion remains a popular method of arthrodesis because it allows access to the anterior weightbearing spinal column through a standard posterior laminectomy. ^[53] This technique seems most ideally suited for cases of mechanical instability that require concomitant spinal canal or disk space entry for decompression. Patient position and initial spinal exposure are similar to those described for intertransverse process fusion. The dissection need only be carried out to the lateral aspect of the facet joints.

A standard bilateral laminectomy or bilateral hemilaminectomies are performed. Removal of the medial two thirds of the facet joints adequately exposes the disk space for graft placement. Epidural veins are cauterized and divided. A wide opening is made into the annulus, and the disk is removed. Sharp osteotomes and ring curets are used to remove the cartilaginous endplates. Bone grafts or implants filled with bone graft are impacted into the disk space and levered medially until 60-80% of the central disk space volume has been filled.

The use of this technique in the paramedial space is known as posterior lateral interbody fusion, whereas a more lateral approach is known as transpedicular interbody fusion. ^{[54, 55]}

A study by Baumann et al found that demineralized bone matrix was an acceptable alternative to autologous bone graft in posterolateral fusion performed to treat acute traumatic vertebral body fractures of the thoracolumbar spine. ^[56]

Anterior corpectomy and fusion

Various approaches to the anterior lumbar and lumbosacral spine have been described. Proper exposure of the anterior lumbar spine requires a detailed knowledge of the neurovascular soft tissue surrounding the anterior spine.

After incision of the abdominal wall musculature, the peritoneal sac is bluntly freed from its attachment to the transversalis fascia until the spine and psoas muscle are identified. The ureter usually remains attached to the posterior peritoneum and is elevated away from the spine during the dissection. It must be identified and protected before any sharp dissection is performed.

The aorta overlies the anterior aspect of the spine and bifurcates into common iliac arteries at about the L4-5 disk space. The inferior vena cava is dorsolateral to the aorta on the right side, and the left common iliac vein crosses the midline behind the iliac arteries and may partially overlie the L5-S1 disk space. Segmental arteries and veins run transversely at the midvertebral body level to enter the aorta and vena cava, respectively. These vessels must be suture-ligated to permit reflection of the great vessels for exposure of the spine.

The lumbar sympathetic chain descends just medial to the psoas muscle and can be identified easily.

Once adequate exposure has been achieved, self-retaining retractors are used. Injury to the great vessels is a common complication of surgery. Therefore, these vessels must be adequately protected during this dissection.

Localization of the vertebral fracture is performed with a cross-table lateral radiograph. Once the correct level has been exposed, the superior and inferior disks are removed by using a long knife, rongeurs, curets, and osteotomes. The vertebral corpectomy is performed by using a high-speed drill, curettes, osteotomes, and rongeurs, with special care taken in approaching the spinal canal.

Once adequate decompression has been achieved, the cartilaginous endplates are removed down to bleeding subchondral bone. Spinal fixation is placed in the adjacent vertebral bodies, and gentle distraction of the corpectomy is achieved with a distractor.

Various donor bone sources are available. The authors prefer to use humerus, femur, or a tibial strut allograft. This can be combined with local autogenous bone from the corpectomy. Autogenous anterior iliac crest bone graft can also be used (see the image below).

The bone graft is carefully shaped to maximize bone contact area and is impacted into the space provided by the corpectomy. The distraction then is removed, further securing the bone graft. A titanium plate or rods are placed on the bolts, securing the graft in position. The retractors are removed, and the wound is then closed in layers. ^[53]

Reported fusion rates and clinical success with anterior interbody techniques are widely variable. Differences probably are related to surgical technique, the source of donor bone, patient selection, and the method by which determination of fusion was evaluated. Internal fixation and direct current electrical stimulation probably enhance fusion rates. ^[57]

In a study that included 89 patients who underwent operative intervention for traumatic lumbar burst fractures, Pham et al found a posterior-only approach to transpedicular corpectomy and instrumented fusion to be a viable treatment option that allowed reconstruction of the anterior column while avoiding many of the risks and complications associated with an anterior or a combined anterior-posterior approach. ^[58]

Posterior internal fixation with pedicle screws

Internal fixation as an adjunct to spinal fusion has become increasingly popular. Titanium rods are longitudinally anchored to the spine by hooks or transpedicular screws. Powerful forces can be applied to the spine through these implants to correct deformity.

Implants provide immediate rigid spinal immobilization, which allows early patient mobilization and affords a more optimal environment for bone graft incorporation. Numerous clinical and experimental studies demonstrate higher fusion rates in patients with rigid internal fixation than in controls without instrumentation. (See the image below.)

Although various implants are available, pedicle fixation systems are the most commonly used implant type in the lumbosacral spine. The large size of the lumbar pedicles minimizes the number of instrumented motion segments required to achieve adequate stabilization. The technique of pedicle fixation requires a thorough knowledge of the pedicle anatomy. ^[59]

Several techniques are available for screw placement, but the authors prefer an entry point into the pedicle at the intersection of the middle of the transverse process, the facet joint, and the pars. ^[60] Once a screw trajectory has been achieved within a pedicle finder, palpation of the cortical margins of the screw tract with a ball tip finder minimizes the penetration of the screw into the spinal canal. A tap is then used to create the threads for the screws.

Finally, the screws can be placed under continuous fluoroscopic guidance. A depth of 50-75% of the anteroposterior (AP) vertebral body diameter is usually recommended for lumbar fixation, while bicortical screw purchase is recommended for sacral fixation. The position of the screws is then assessed electrophysiologically with a nerve stimulator and radiologically with an AP, lateral, and two-dimensional scan of the spine performed with an isocentric C-arm.

Fenestrated pedicle screws may be augmented by the use of polymethylmethacrylate (PMMA) cement in patietns with osteoporotic thoracolumbar fractures. ^[61]

Kyphoplasty

Compression fractures with an intact posterior cortical wall can be treated by means of a kyphoplasty, ,which involves transpedicular placement of a balloon through a bone biopsy needle and cannula into the compressed vertebral body under fluoroscopic guidance. The balloon is inflated under controlled pressure, resulting in expansion of the vertebral body and creation of a cavity. The cavity is then filled with bone cement. This results in elevation of the endplate and stabilization of the fracture fragments, with a consequent reduction of pain. ^{[62, 63, 64]} (See the images below.)

A posterior cortical defect in a burst fracture is considered a contraindication for kyphoplasty. 

For a comparison of vertebroplasty and kyphoplasty, see Hiwatashi et al ^[65] and Karlsson et al. ^[66]

Significant postoperative discomfort limits activity for several days in most patients. A morphine patient-controlled analgesia pump usually is employed during the first 36-48 hours. A molded lumbar or thoracolumbar orthosis is often worn for 3 months.

One study evaluated the effects of two different doses of perioperative pregabalin administration in patients undergoing spinal fusion surgery. ^[67] The study found that pregabalin 150 mg, but not 75 mg, administered prior to and 12 hours after surgery significantly reduced the use of postoperative opioid consumption for 48 hours without significant side effects.

During the postoperative period, patients with fractures that have resulted in neurologic deficits are prone to multiple complications, including skin decubitus, pulmonary problems, and urinary sepsis (see below).

Nursing care should include frequent repositioning, vigorous pulmonary toilet, and deep venous thrombosis (DVT) prophylaxis.

Intermittent pneumatic compression stockings are indicated for all patients with spinal injuries. If the patient is neurologically intact, pulsatile stockings alone suffice. However, if the patient has neurologic compromise, pulsatile stockings and low-dose subcutaneous heparin are used in combination to prevent DVT. If the patient is immobilized from multiple injuries, heparin should be started after postoperative day 2, even if he or she is neurologically intact.

Intermittent catheterization should be performed in patients with spinal cord injuries and urinary retention. A bowel regimen consisting of stool softeners and suppositories always should be instituted in these patients.

Patients with spinal cord injuries are prone to multiple complications, including decubitus ulcers, pulmonary problems, urinary sepsis, and new fractures. ^[68]  Occasionally, patients develop delayed progressive neurologic deterioration months to years after sustaining spinal trauma as a result of instability and progressive spinal deformation.

Intraoperative complications

Neurologic deterioration can occur from neural traction, compression, or interruption of the vascular supply to the neural elements. The overall risk of neurologic injury from posterior instrumentation is 1-3%. In addition, postoperative neurologic deterioration may occur from graft dislodgment, displacement of the hardware, or hematomas.

Intraoperative injury to major vessels and viscera may occur during vertebral exposure and reconstruction. Dural tears, which may be the result of bone fragments or may occur during the surgical approach, can result in cerebrospinal fluid (CSF) leaks.

Failure of the fusion

Pseudarthrosis is a cause of chronic pain as result of the malunion of the fusion. It may lead to progressive deformity, neural compromise, and pain. Failure of the instrumentation, such as dislodgment or breakage, is usually related to pseudarthrosis.

Infections

Infections can occur after spine surgery, especially after a long surgical procedure for a complicated instrumentation placement. Superficial infections should be opened and debrided. The wound may be packed open or closed using retention sutures. Appropriate antibiotics should be employed, starting with coverage against gram-positive cocci and adjusting in accordance with culture results. All attempts should be made to keep the instrumentation and graft in place until the fusion is solid.

Thromboembolic disease

DVT is a significant potential complication in patients with spinal fractures. Thromboembolism has been reported to occur in as many as 70% of patients with complete motor paralysis. Pulmonary embolism (PE) significantly affects the probability of survival after a spinal fracture. Mortality figures for patients with PE have not decreased significantly in the last 30 years, emphasizing the need for more effective preventive measures.

Recommendations for prophylaxis are varied and usually include subcutaneous or low-molecular-weight heparin (LMWH), sequential compression stockings, and elastic hose placed on the lower extremities. Patients who develop DVT should be treated aggressively with anticoagulation. If the risk for systemic anticoagulation is prohibitive, thrombectomy or placement of a vena caval filter is an option.

Stress ulcers

The stress resulting from a traumatic injury, a complicated surgery, and mechanical ventilation can predispose a patient to gastric ulcers. However, the widespread use of prophylactic agents, such as H2-receptor blockers, sucralfate, and proton pump inhibitors (PPIs), has reduced the incidence of severe bleeding from stress ulcers.

Adynamic ileus and Ogilvie syndrome

Ogilvie syndrome, also known as pseudo-obstruction of the colon, is characterized by massive abdominal distention with a cecal diameter of more than 9 cm. Nausea, vomiting, diarrhea, and severe abdominal distention are common symptoms.

Preventive measures for both Ogilvie syndrome and adynamic ileus include minimizing bed rest, returning to ambulation as early as possible, and limiting the use of narcotics. Early recognition and treatment of these conditions are essential to reduce morbidity and mortality. Initial treatment includes cessation of oral intake, nasogastric suction, insertion of rectal tubes, and cessation of narcotics.

Genitourinary complications

Urinary complications continue to be significant sources of morbidity after spinal injuries. In patients with spinal cord injuries, distention of the bladder can lead to autonomic dysreflexia, impairment of bladder sensation, detrusor hyperreflexia, and sphincter dyssynergia, which can lead to renal damage from hydronephrosis or vesicourethral reflux. These complications are decreased with indwelling Foley catheters. In patients with spinal cord injury, the most frequent source of morbidity is sepsis related to urinary tract infections.

The fusion is evaluated by means of plain radiography, including flexion and extension views, at 6 weeks, 3 months, and 6 months postoperatively. If there is any doubt, computed tomography (CT) is performed.