Traumatic lumbar spondylolisthesis without facet fracture at L4/L5. A case report and literature review

The first case of L4-L5 traumatic spondylolisthesis was reported in 1940 by Watson Jones [1]. L4-L5 traumatic spondylolisthesis are quite unusual. The most frequent reported location is at L5-S1 [4]. In all of these reported cases traumatic spondylolisthesis was caused by improper use of a seat belt. The seat belt was without abdominal strap. Traumatic spondylolisthesis of the spine as a result of improper use of seat belt is considered as pathology of the seat belt without abdominal strap. L4-L5 traumatic ante-rolisthesis and retrolisthesis have similar physio pathological mechanism [8]. The direct shearing force at the lower lumbar area is also a major cause. The high-energy trauma produced disruptions of the posterior ligamentous structures; the facet sand the vertebrae body fractures, and anterior sliding of the L4 vertebrae body, which resulted in a great instability of Denis’s 3 columns. Traumatic spondylolisthesis at L4-L5 is associated with incorrect use of a three-point seat belt. Lumbar facet joints anatomy play major role in L4-L5 traumatic spondylolisthesis. The mechanism of injury seems to be forcible hyperextension [8, 9]. However, hyperflexion with varying degrees of distraction is the most frequent mechanism of facet dislocation in the lumbar spine [4, 10, 11]. Hyperflexion alone is able to produce either pure dislocation or fracture-dislocation in the lumbar spine [9]. Therefore, in this case, we consider that, the mechanism of injury was a combination of hyperflexion, distraction, and rotation. The hyper-sagitalisation of superior articular processes could be the main factor that prevents the occurrence of dislocations [11]. Paravertebral lumbar muscles play a potential role in lumbar stability [10]. There are disruptions of the posterior ligamentous complex associated with facet dislocation [5, 7, 12]. Any fortuitous discovery of fractures of the transverse processes should warrant a search for a lumbar dislocation and vice versa. Moreover, the frontal orientation of S1 upper articular process almost always triggers a dislocation to the L5-S1 joint [8]. However, the ilio-lumbar ligament serves as a bulwark to prevent this type of traumatic injury. In our case report the mechanism is different because the driver was not thrown out of his vehicle. Hyperflexion of the trunk could explain the L4-L5 dislocation. The unusual L4-L5 level facet interlocking was attributed to the misuse of the automobile shoulder harness. It is important to recognize this injury and follow up on such clues.

The exploration must be multidirectional with 3D CT scan. A careful clinical examination and analysis of CT scan or MRI result in a diagnosis of lumbosacral dislocations. Meticulous clinical examination and careful imaging assessment, including CT scan and MRI, provide an early diagnosis in cases of lumbosacral dislocation [12]. MRI demonstrates a disruption of the posterior ligamentous [3, 12, 13]. Initially the treatment is conservative and involves hospitalization with bed rest and more analgesics; then surgical treatment is indicated. Lumbar spine trauma occurred during road traffic accident. In our report the transportation of patient to the neurosurgical emergency unit was not medicalized. The injuries initially without gravity could become significant with sensory-motor deficits. They will leave high sequelae despite prompt and adequate surgery. Finally, surgical treatment was a L4-L5 laminectomy, cage, and fixation by four pedicular screws connected by two parallel rods. Open reduction and circumferential bony fusion restored segmental stability and painless function [13]. The patient was mobilized in an armchair after two days of a total resolution of the painful symptoms. Methods used by most authors lead to a favorable outcome. The introduction of early physiotherapy promotes rapid recovery in the event of a sensory-motor deficit. In our case the patient benefited from therapy sessions from the seventh day of his surgery. Two months later, he could walk with a walking frame. This reinforces hypothesis that early physiotherapy sessions in the event of sensory-motor deficit would promote recovery without sequelae. The sphincter disorders as acute urinary retention are not frequently associated with neurological disorders of lumbar dislocation L4-L5. Sphincter disorders regression are earlier than motor ones. Unlike the present case, acute retention of urine persisted beyond three months before disappearing. Once again the interest of physiotherapy as soon as possible. After 25 months the patient had no neurologic deficit. He was pain-free and had no restriction of mobility of lumbosacral spine. The radiograph revealed the release of a screw head associated with a rupture of one of L5 pedicle screw dislocation. Some authors report early decompression of the spinal cord performed at 24 h in dogs, the improvement in somatosensory evoked potentials was only 26 %, compared to 85 and 72 % improvement achieved when decompression was carried out immediately and one hour after injury, respectively [14].

L4-L5 traumatic spondylolisthesis is rare, when it happens; physicians should always systematically search for fracture of the lumbar transverse processes. Meticulous clinical examination and careful imaging assessment, including CT scan and MRI, assist with an early diagnosis in cases of lumbosacral dislocation. Open reduction and circumferential bony fusion; restore segmental stability and painless function.