Post-traumatic unilateral lumbosacral ligamentous instability

Post-traumatic unilateral lumbosacral ligamentous instability

Case reports 279 Post-traumatic unilateral lumbosacral ligamentous instability I. Jakim, D. V. Meerkotter and M. B. E. Sweet Bone and Joint Research...

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Case reports

279

Post-traumatic unilateral lumbosacral ligamentous instability I. Jakim, D. V. Meerkotter and M. B. E. Sweet Bone and Joint Research Unit, Hillbrow Hospital and University of the Witwatersrand, Johannesburg, South Africa

A 23-year-old miner was struck from the right side following the collapse of an underground mine prop which fell directly onto the lateral aspect of his torso. A shelf of rock supporting the left leg

and hip prevented him from falling over and he was hinged laterally by the force. He sustained fractures of five right ribs and abrasions of the ;right flank, and was found to have marked associated tenderness and pain localized to the Iumbosacral junction. There was no neurological deficit at any time. Significant radiological features were as follows: vertical fractures of the four upper right transverse processes; horizontal fracture of the right 5th transverse process. In addition, forward subluxation of L5 on $1 amounting to 2-3 mm was noted on the lateral views. Computerized tomographic scanning revealed a normal L5-SI articulation and no fracture or dislocation. In the light of the clinical and radiologicaI findings dynamic studies Were performed: on controlled left lateral bending lateral divergence of L5 on $1 was observed (Figure1). This reduced completely on lateral bending to the right (Figure 2). The L5/$1 segment was arthrodesed by a standard posterolateral fusion, instrumented with interpedicular screws and plates (Figure 3). At surgery no evidence of facet joint fracture was noted at this level. The horizontal fracture of the right transverse process

Figure 1. Anteroposterior view with controlled lateral bending to the left. Note horizontal fracture through transverse process of L5 with divergence of L5 and $1 in coronal plane.

Figure 2. Anteroposterior view with controlled bending to the right. Note anatomic reduction of L5 and $1.

Introduction The lumbosacral segment differs markedly from the remainder of the lumbar spine in respect of its anatomy, kinematics and kinetics (Posner et al., 1982). The lumbosacral joint offers more sagittal plane motion than do the other lumbar joints. On the other hand, the degree of lateral bending and rotation are less than at any other segment (White and Panjabi, 1990). For these reasons most, if not all, fracturedislocations at this level have occurred in the sagittal plane, together with an element of rotation. We report a unique case of post-traumatic ligamentous instability at the L5-SI level in the coronal plane.

Case report

© i992 Butterworth-Heinemann Ltd

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280

Injury: the British Journal of Accident Surgery (1992) Vol. 23/No. 4

detected. This illustrates the value of such an investigation in these specific cases, although dynamic views are generally not indicated in acute lumbar injuries. White and Panjabi (1990) have recommended dynamic radiographs where, inter alia, on static (resting) views, sagittal plane displacement of more than 4.5 mm or 15 per cent of the anteroposterior diameter of the vertebral body is present. In the light of our experience this value may be conservative. By all criteria of lumbar stability, this injury must be classified as unstable (Denis, 1983; Louis, 1985). This coronal-plane ligamentous injury could be compared with a pure Chance-type dislocation in the sagittal plane. In both instances static radiographs can be most misleading. This further strengthens the argument in favour of carefully controlled dynamic views.

References

Figure 3. Lateral radiograph after segmental spine fusion.

was noted. The ligamentum flavum,the interspinous ligament and the capsular ligaments of the right facet joint had been ruptured. Gross lateral mobility could be demonstrated by levering the inferior facet of L5 with a Cobb's dissector. The patient recovered uneventfully.

Discussion The association of multiple transverse process fractures with lumbosacral fracture-dislocation is well established (Dewey and Browne, 1968; Herron and Williams, 1984). A further key to the diagnosis is a forward subluxation of L5 on $1 (Morris, 1981). Our case was unique in that there was dynamic lateral instability of the L5-$1 segment. Further, apart from that of the transverse process, there was no fracture or dislocation at the L5-$1 segment, and it was only on careful dynamic views that a pure lateral subluxation was

Denis F. (1983) The three-column spine and its significancein the classification of acute thoraco-lumbar spine injuries. Spine 8, 817. Dewey P. and Browne P. S. H. (1968) Fracture-dislocation of the lumbo-sacral spine with cauda equina lesion. J. Bone Joint Surg. 50B, 635. Herron L. D. and Williams R. C. (I984) Fracture-dislocationof the iumbosacral spine. Clin. Orthop. 186, 205. Louis R. (1985) Spinal stability as defined by the three-column spine concept. Anal Clin. 7, 33. Morris B. D. A. (1981) Unilateral dislocation of a lumbosacral facet.J. Bone Joint Surg. 63A, 164. Posner I., White A. A. III, Edwards W. T. et al. (1982) A biomechanicalanalysis of the clinicalstability of the lumbar and lumbosacral spine: Spine 7, 374. White A. A. III and Panjabi M. M. (1990) Clinical Biomechanics of the Spine. 2nd Ed. Philadelphia:Lippincott, 106, 354. Paper accepted 16 August 1991.

Requests for reprints should be addressed to: Mr I. Jakim,Department of Orthopaedics, Medical School, York Road, Parktown 2193, South Africa.

Associated soft tissue injury of fracture of the body of talus T. B. M. Niazi, R. P. Joshi and P. G. Johnson Orthopaedics Department, Frimley Park Hospital, Frimley, Surrey, UK

Introduction

Case report

This article presents a soft tissue injury associated with a fracture of the body of talus. Known soft tissue complications of such fractures include skin necrosis and neurovascular injuries, but loss of active extension of the great toe at the metatarsophalangeal (MTP) joint, due to involvement of the flexor hallucis longus tendon, has not, we believe, been described in the literature. © 1992 Butterworth-Heinemann Ltd 0020-1383/92/040280-02

A 38-year-old builder sustained a coronal fracture through the anterior third of the body of talus (Sneppen et al., 1977), as a result of falling 2.5 m (Figure 1). The fracture was manipulated under a general anaesthetic and fixed with two percutaneous Kirschner wires (K-wires).The joint was aspirated and the ankle was splinted in a below-knee cast for 3 months (Figure2a, b). The K-wires were removed after 4 weeks.