Traumatic transverse fracture of sacrum with cauda equina injury--a case report and review of literature.

H Singh, VS Rao, R Mangla, VJ Laheri 
 Department of Orthopaedics, Seth G.S. Medical College, Mumbai.

Correspondence Address:
H Singh
Department of Orthopaedics, Seth G.S. Medical College, Mumbai.

Full Text

::   Introduction

Since the first case report of sacral fracture with injury to cauda equina in 1945[1], there have been sporadic reports of such fracture in the literature. We report an unusual case of transverse sacral fracture with neurological damage, which presented to us after three weeks of injury.

::   Case report

A twenty-year-old male fell from a tree, 25 feet high. Immediately after the fall, the patient had weakness in both the lower extremities and inability to void urine and was catheterised at local hospital. He presented to us after three weeks of injury. On examination, he was found to have saddle anaesthesia, total bladder and bowel incontinence, poor anal tone, absent anal wink and bulbocavernous reflex with no appreciable motor weakness in the lower limbs. Roentgenograms revealed irregularity in the arcuate lines of the upper three sacral foramina, a transverse fracture sacrum through second and third sacral vertebrae with vertical fracture of the foramina on right side and L5 transverse process fracture. Magnetic resonance imaging (MRI) showed sacral fracture with anterior displacement of the distal fragment with effacement of the thecal sac at S2 level [Figure:1]. As the patient showed no recovery at 6 weeks following injury, patient was taken up for surgery. Sacral laminectomy at the level of S2-3 showed anterior displacement of the distal fragment and posterior angulation at fracture site and there was complete avulsion of S3,4,5 nerve roots on right side and S4,5 on left side. S3 nerve root was found stretched on the internal gibbus. Internal gibbectomy [Figure:2] along with foraminotomies were performed. Neurorraphy was attempted for avulsed roots. Post operative period was uneventful as regard wound healing. Patient showed partial recovery of bladder function, anal tone and sensations (sensation fully recovered on S2 on right side and S3 on the left side) on repeated examinations and cystometry. Patient can sit comfortably without pain and was ambulatory.

::   Discussion

Transverse fracture of sacrum are usually due to direct injury[2] which often result in angular deformity and displacement of distal fragment producing neurological damage. The transverse sacral fracture have been classified as upper and lower fractures.

Upper sacral transverse fracture results from flexion injury involving usually slippage of S1 on S2[3]. These fracture are often associated with vertical fracture through foramina and fracture transverse process of lumbar vertebrae[4]. A particular posture at the time of injury involving fixed pelvis, flexion at hips, and extension at knee has been stressed[5],[6],[7] as in the present case. These fracture are unstable and usually need decompression via sacral laminectomy in case of neurological damage with special precaution to avoid flexion posture, as late neurological damage has been reported[4],[5],[8].

Lower sacral transverse fracture are often due to direct traumatic force against coccyx due to fall resulting in break at the kyphos of sacrum mostly through the body of S4 although any of the lower 3 sacral vertebrae can involved. Rarely, it can produce neurological damage[9]. Sacral laminectomy is indicated after a trial of conservative treatment in case of neurological deficit. The neurological damage often is unilateral[3] and return of partial function is possible in sacral fractures because of bilateral supply of pelvic organs. In the case discussed recovery of the partially injured nerve roots might have contributed to the partial recovery of the bladder and bowel functions. Results of operative decompression are debatable[4],[5],[10],[11] and even conservative treatment has been advocated[12]. However, in case of sacral root injuries with displaced sacrum fracture decompression is warranted as the neurological deficit may not only be due to root avulsion but also as a result of nerve stretching as in the present case. The bony prominence has also been found to be causing difficulty in sitting and sacrodynia[13] and gibbectomy is especially indicated in such cases.

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