Keywords
spinal fractures - dislocations - thoracic vertebrae - surgical procedures
Palavras-Chave
fraturas de coluna - luxações - vértebras torácicas - procedimentos cirúrgicos
Introduction
The thoracolumbar junction is located between the relatively stable thoracic spine
and the mobile lumbar spine. This may lead to a predisposition to certain types of
traumatic injuries.[1]
[2] The thoracic spine is rigidly stabilized by anterior and posterior longitudinal
ligaments, by the ribs, with their costotransverse ligaments and their articulation
with the manubrium and the spine, by the ligamentum flavum, and the sagittal orientation
of joints wich resists axial rotation and horizontal translation.[3]
[4]
[5]
[6] Because of that, it takes a great force to cause a fracture dislocation in the thoracic
spine. Thoracic fractures with displacement in which the neurological status is normal
or near normal are rare. This type of injury leads to complete paraplegia in 80% of
cases.[3]
[5] Cases of thoracic trauma with fracture type C in which neurological function is
normal, as demonstrated in this case, are even rarer. In this report, we present one
case of rotational traumatic fracture and lateral dislocation (AOSpine - type C) involving
the thoracic spine, and discuss the surgical strategies used to manage it.
Case
This 40-year-old man was bicycling when he was hit by a car. He was brought to the
emergency unit with severe pain in his back and left leg. Neurological examination
showed no evidence of motor or sensitive deficits. After clinical evaluation, a thoracolumbar
computed tomography (CT) scan was performed, as shown in [Fig. 1].
Fig. 1 A computed tomography (CT) scan showing complete lateral dislocation between T11
and T12 in the coronal (A), sagittal (B) and axial (C and D) images. In C, the spinal
canal was “opened,” and that potentially explained why this patient had neurological
preservation.
A T11–T12 severe fracture-dislocation – classified as a type C injury according to
the new AO Classification System – was the diagnosis.[7]
[8] His Thoracolumbar Injury Classification System score was of 6 points (3 for rotational,
3 for posterior ligamentous complex injury, and 0 for neurological status), and surgical
treatment was then indicated.[9] He also had pedicle and laminar fractures ([Fig. 1]). The spinal canal was “opened” by the lamina fractures, and that potentially explained
the neurological preservation ([Fig. 1]).
Surgical procedure: an intraoperative neurophysiology monitoring standard protocol
with lower limb Somatosensory Evoked Potentials (SEP) and lower and upper limb Transcranial
Motor Evoked Potential (TCMEP) was applied. A wide laminectomy with concomitant facetectomies
from T11–T12 was performed to avoid a new compression in the reduction maneuver and
release the spine. Pedicle screws were inserted at T10–T11 and L1–L2 bilaterally.
A temporary spinal rod was connected at the right T10–T11 screws, and another was
used at the right L1–L2 screws. Distraction of the segment with manual reduction and
spinal realignment was then performed, checking for TCMEP. A definitive rod was then
inserted at the left T10–L2 screws, and the temporary right rods were removed. Finally,
a definitive rod was attached on the right side ([Fig. 2]–intraoperative view). Bone graft harvest from the laminectomies and the facet joints
were used for a posterolateral fusion.
Fig. 2 Intraoperative view of the thoracic spine injured after muscular dissection (A);
after T11–T12 laminectomy and screw insertion (B); and after correction of the dislocation
with rod connection (C).
Normal values of SEP and TCMEP obtained before surgery were maintained until the end
of the surgery without significant change. After the procedure, the patient was neurologically
intact. He was able to walk three days after surgery, and was discharged to his home
on the eighth day. After six months, he had some mild occasional pain, but was able
to practice physical activities, and was neurologically intact.
Discussion
We retrieved in our literature review just 15 well-documented cases of fracture-dislocation
of the thoracic spine in which the neurological function was demonstrated as normal
or near normal.[3]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
By definition, fracture-dislocation involves the disruption of all the elements of
the spine.[1]
[21] Bohler subdivided fracture-dislocation in translational or rotational displacement
without lamina and pedicle fracture, which was associated with a high incidence of
paraplegia.[4] The majority of fractures and dislocations of the thoracic spine with spinal cord
preservation are located between T6 and T9.[15] This fact occurs because in this area the spinous processes extend inferiorly more
than any other segment of the spine. Consequently, high shear forces would be concentrated
in the middle column, leading to fractures of both pedicles and preservation of the
spinal canal,[16] in accordance with what occurred in our presented case. Twenty percent of the injuries
described in the original series of Denis[6] were fracture-dislocation, with the majority having occurred at the thoracolumbar
junction. Fracture-dislocation is further characterized in shear, bending-rotation
or flexion-distraction. According to the Thoracolumbar Injury Classification and Severity
Score (TLICS), fracture-dislocation (translational serious injury with disruption
of the posterior ligamentous complex with or without neurological deficit) is considered
a very unstable injury.[7]
[22]
[23]
[24]
[25] The correct management of thoracolumbar spine trauma involves multiple steps, such
as precise diagnosis, classification, and treatment.[26]
[27]
Operative techniques for this spinal injury must provide options for distraction of
the impacted vertebral bodies, restoration of sagittal and coronal misalignments,
and maintenance of correction with stable segmental internal fixation. Vertebral body
and laminar spreading instruments are extremely useful in vertebral element distraction
and restoration of alignment.[1] The surgical technique includes: spinal cord wide decompression to avoid injury
during realignment, and also “release” of the spine for realignment; instrumentation
with pedicle screws; correction of the deformity and misalignment using rod maneuvers,
such as temporary rods; and posterolateral arthrodesis for fusion.
Fracture-dislocation of the thoracic spine without neurological deficit is a rare
injury. In this case, we have attributed the neurological preservation to the fact
that the fracture “opened” the spinal canal. A good outcome can be obtained with modern
spinal stabilization surgical techniques.
