Spinal cord decompression sickness associated with scuba diving: correlation of immediate and delayed magnetic resonance imaging findings with severity of neurologic impairment--a report on 3 cases.

BACKGROUND: There are few reports detailing an association between immediate and delayed changes in MR imaging findings and severity of neurologic impairment in patients with spinal cord DCS. We report on the cases of 3 patients diagnosed with spinal cord DCS presenting with severe neurologic symptoms after scuba diving. CASE DESCRIPTION: Of 175 patients with DCS referred to the Tokyo Metropolitan Ebara Hospital Department of Neurosurgery, 3 were determined by MR imaging and neurologic examination to have a spinal cord injury. Hyperbaric oxygen, methylprednisolone, and rehabilitation therapies were applied to these patients. We examined whether the severity of the patients' neurologic dysfunction, classified according to Fränkel's grade, was associated with the extent of abnormal signals depicted by spinal MR imaging in these patients at the acute phase and monthly follow-up points. T2-weighted MR imaging performed within 24 hours of the onset of the patients' neurologic symptoms revealed signals of increased intensity located predominantly in the dorsolateral regions, involving spinal segments 1 through 4, and a neurologic examination upon admission revealed severe sensory and motor dysfunction (Fränkel's grade A) in all 3 patients. The abnormal signals on MR images at 1 month postinjury were markedly decreased in size as compared with those at the acute phase. However, neurologic function showed minimal or no improvement (Fränkel's grade A or B).
CONCLUSION: In patients with spinal cord DCS, the improvement in MR imaging findings was not associated with improved clinical status. This discrepancy suggests that intricate pathophysiologic changes, reversible and persistent damage subsequent to initial cord injuries (ie, edematous and neurotoxic lesions), underlie the disease and affect the clinical course.