Subacute Progressive Ascending Myelopathy

Introduction

Subacute progressive ascending myelopathy (SPAM) is an exceedingly rare and poorly understood complication of spinal cord injury. As the natural history of this process is quite peculiar, it is especially important for the imaging interpreter to be aware of this entity. Following a latent period a few weeks after spinal cord injury, patients usually present with an abrupt ascending neurologic deficit. The sudden onset of symptoms correlates with a characteristic and often dramatic extent of spinal cord edema extending more than four levels above the site of initial spinal cord injury. Remarkably, after a period of several months, near complete resolution of the ascending neurologic deficit and associated edema cephalad to the initial injury site is seen. Only a small focal area of myelomalacia close to the site of initial injury remains after resolution. Of the cases where SPAM reaches the brain stem, loss of vital functions may be fatal prior to resolution. There is no known effective treatment.