Guidelines Summary
The American College of Radiology Appropriateness Criteria has noted the following recommendations [1] :
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CT is preferred to radiographs for initial assessment of spine trauma.
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CT angiography and MR angiography are both acceptable in assessment for cervical vascular injury.
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MRI is preferred to CT myelography for assessing neurologic injury in the setting of spine trauma.
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MRI is usually appropriate when there is concern for ligament injury or in screening obtunded patients for cervical spine instability.
Guidelines for the treatment of lumbar and thoracic spine fractures were 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. They are summarized below [31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43] :
Nonoperative care
Whether to use an external brace is determined at the discretion of the treating physician. Nonoperative management of neurologically intact patients with thoracic and lumbar burst fractures, either with or without an external brace, produces equivalent improvement in outcomes. Bracing is not associated with increased adverse events.
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. 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.
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. [53, 54]
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.
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. [52]
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. 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.[58]
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.
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Anteroposterior and lateral radiographs of an L1 osteoporotic wedge compression fracture.
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Fluoroscopic view of a kyphoplasty procedure.
