Decision-making in burst fractures of the thoracolumbar and lumbar spine

Abstract

The most common site of injury to the spine is the thoracolumbar junction which is the mechanical transition junction between the rigid thoracic and the more flexible lumbar spine. The lumbar spine is another site which is more prone to injury. Absence of stabilizing articulations with the ribs, lordotic posture and more sagitally oriented facet joints are the most obvious explanations. Burst fractures of the spine account for 14% of all spinal injuries. Though common, thoracolumbar and lumbar burst fractures present a number of important treatment challenges. There has been substantial controversy related to the indications for nonoperative or operative management of these fractures. Disagreement also exists regarding the choice of the surgical approach. A large number of thoracolumbar and lumbar fractures can be treated conservatively while some fractures require surgery. Selecting an appropriate surgical option requires an in-depth understanding of the different methods of decompression, stabilization and/or fusion. Anterior surgery has the advantage of the greatest degree of canal decompression and offers the benefit of limiting the number of motion segments fused. These advantages come at the added cost of increased time for the surgery and the related morbidity of the surgical approach. Posterior surgery enjoys the advantage of being more familiar to the operating surgeons and can be an effective approach. However, the limitations of this approach include inadequate decompression, recurrence of the deformity and implant failure. Though many of the principles are the same, the treatment of low lumbar burst fractures requires some additional consideration due to the difficulty of approaching this region anteriorly. Avoiding complications of these surgeries are another important aspect and can be achieved by following an algorithmic approach to patient assessment, proper radiological examination and precision in decision-making regarding management. A detailed understanding of the mechanism of injury and their unique biomechanical propensities following various forms of treatment can help the spinal surgeon manage such patients effectively and prevent devastating complications.

Keywords: Burst fracture; lumbar fracture; thoracolumbar fracture.

Figure 1.1

Lateral plain film radiograph (a) demonstrates a 17% loss of height at L1 and a 50% loss of height at L2. AP plain film (b) radiograph demonstrates a focal translation at the level of the L1-L2 subluxation causing a coronal plane deformity. An inferior vena caval filter is visualized

Figure 1.2

Axial CT scan (a) image at the level of the L2 pedicles demonstrates a 70% compromise of the spinal canal area by a large retropulsed fragment of the vertebra. Of note, the L1 vertebra had a 55% loss of spinal canal area. The patient was operated for -AP spinal reconstruction: Anterior surgery includes corpectomies of L1 and L2, placement of a stackable carbon fiber cage filled with autograft bone anteriorly from T12 - L3 and stabilization with a Kaneda screw-rod construct. Posteriorly the stabilization with bilateral pedicle screws at T11 and L4, bilateral hooks at T12 and L3, two rods with two crossconnectors and generous amounts of autologous iliac crest bone graft was done. (b) Axial CT scan at the level of the T11 pedicles demonstrates well-positioned pedicle screws which approach the far bony cortex of the T11 vertebra. Axial CT scan (c) at the level of the L3 pedicles demonstrates the inferior Kaneda screws which are placed across the vertebra to achieve bicortical fixation. Axial CT scan (d) through the L2 level which shows the pedicle-to-pedicle decompression of the spinal canal with the carbon fiber cage filled with autograft

Figure 1.3

Sagittal reconstruction of a CT scan (a) of the same patient as fig 1.1 & 1.2 demonstrating good positioning of the stackable carbon fiber cage with complete decompression of the spinal canal. Kaneda screws are seen at T12 and L3. Coronal reconstruction of a CT (b) scan demonstrating good positioning of the stackable carbon fiber cage and the Kaneda screw-rod fixation device. AP plain film radiograph (c) obtained two years after surgery demonstrates solid fusion and excellent alignment. Lateral plain film radiograph (d) at two years postoperatively demonstrates preservation of sagittal alignment. At five years post-injury, the patient was neurologically intact with normal bowel and bladder function. She was gainfully employed and despite a solid T11-L4 fusion, she was able to forward bend and touch her toes with her knees fully extended. She required no pain medications