Traumatic L5-S1 spondylolisthesis: report of three cases and a review of the literature

Abstract

IntroductionTraumatic lumbosacral spondylolisthesis is a very uncommon lesion. The literature testifies to this rareness, reporting only 22 cases over the last 50 years [1, 2, 4, 5, 7, 9-11, 13-15, 21, 22]. These include seven cases of pure bilateral dislocation [1,4,5,7,11,15,22]. The specific features of the lesion, as well as the different possible radiographic and clinical findings that characterize it, have encouraged many researchers to attempt to propose possible interpretations of the kinematics of the lesion. PathomechanicsThe mechanics of the lesion, on the basis of its rareness and its association with monolateral fractures of the lumbar transverse apophyses, which occur in a very high percentage of cases, has been the subject of numerous studies, the conclusions of which often appear to disagree.Hyperextension has been pointed to as an efficient traumatic vector [23]; other authors appear to disagree, believing that the main mechanism responsible for the lesion is constituted by the association between hyperflexion, compression and rotation [4,11,21,24], or by the action of the direct traumatic vectors [1,17].In the cases that came to our observation, an accurate history of each patient allowed us to generally reconstruct the dynamics of the trauma. The patient with a "pure" dislocation had undergone sudden hyperflexion of the lumbosacral spine, with his thighs flexed on the pelvis. This had been provoked by doing a somersault in the air and landing on his bottom. In the patient with fracture-dislocation, the main traumatic mechanism had been violent and direct posterior trauma in the lumbar spine (the patient had been thrown from a motorcycle ending up against a pole). This mechanism, in clear contrast to what has been affirmed by Roaf [20], appears to be similar to that described by Beguiristain et al. [1], and it may be likened to an actual lesion caused by the application of shear traumatic vectors. AbstractThe literature reports that traumatic spondylolisthesis of L5 is an uncommon lesion. The authors report their experience of three cases of this particular fracture-dislocation of the lumbosacral spine. They stress the importance of certain radiographic signs in the diagnosis: namely, the presence of unilateral multiple fracture of the transverse lumbar apophysis. As far as the treatment is concerned, they state the need for an open reduction and an internal segmental fixation by posterior approach. A preoperative MRI study appears mandatory in order to evaluate the integrity of the L5-S1 disc. In the event of a traumatic disruption of the disc, they state the importance of posterior interbody fusion by means of a strut graft carved from the ilium or, in case of iliac wing fracture (which is not uncommon in these patients), by means of interbody cages.Key words Lumbosacral spine · Fracture-dislocations · Traumatic L5-S1 spondylolisthesis · Surgical treatment ORIGINAL ARTICLE Eur Spine J (1999) 8 : 290-295

Traumatic bilateral locked facet at L4-5: report of a case associated with incorrect use of a three-point seatbelt

“…With the fulcrum anterior to the spine, the resultant momentum, along with shear and tensile forces, results in a transverse disruption of the intervertebral mobile segment, from the supraspinous ligament to the anterior annulus [19]. To our knowledge, most of the reported traumatic lumbar dislocations have been at the L5-S1 level [3,4,7,8,9,10,11,14,16,22], and none have been a traumatic L4-5 dislocation. A previous study revealed the lumbar facet orientation in a normal lumbar spine, and noted that the facet joint and laminae are more sagittally oriented at the L4-5 level, while at L5-S1 they are more frontally oriented [21].…”

“…However, some seatbelt-associated injuries have been reported [2,5], among which bilateral lumbar facet dislocations are uncommon. Previous reports have noted only a few traumatic bilateral lumbar facet dislocations, all of which occurred at the lumbosacral junction [3,4,8,11], and some classifications of lumbar and lumbosacral injuries have been reported [1,6,13]. According to the main mechanism of injury and pathomorphological pattern, and in consideration of the prognostic aspects regarding healing potential, Magerl et al [13] comprehensively classified thoracic and lumbar injuries into three types.…”

Unilateral Lumbosacral Facet Interlocking without Facet Fracture

“…The forces producing the lesion have been postulated to be hyperflextion for the pure dislocations and hyperflexion in combination with compression or axial translation in cases with significant fractures of the fifth lumbar vertebrae. It is frequently associated with neurologic deficit, although total cauda equina lesion is rarely found 1, 4,5,10,11) . The current premise in the management of traumatic fracture dislocation of the lumbosacral junction is to restore the normal alignment and stabilize these highly unstable injuries, by open reduction of the dislocation and rigid fixation of the affected segment 3,12) .…”

“…Acute traumatic spondylolisthesis is a rare condition 3,4) . It usually involves subluxation or fracture-dislocation of the facet joints, which may be unilateral or bilateral.…”

Expert’s comment concerning Grand Rounds case entitled “Floating lumbar spine: proposed mechanism with review of literature” (K. Das et al., Eur Spine J. doi:10.1007/s00586-016-4690-2)

“…Traumatic spondylolisthesis has consistently been linked to high-energy trauma despite the lack of agreement in the literature on the mechanism (i.e., forced hyper-extension, forced hyper-flexion with compression, or horizontal shear combined with rotation) [2][3][4][5]. Although a rare injury, a high index of suspicion and early investigation remains a cornerstone in the diagnosis.…”