Incidence of Sciatica following Subarachnoid Hemorrhage

The patient is a 63-year-old female librarian. Over the past 10
years she has had three bouts of subarachnoid hemorrhage
related to an arterial/venous malformation in the left base of the
skull. Within three to five days following these hemorrhages, the
patient has had severe sciatic symptoms. During those periods the
patient had not changed her level of physical activity to
precipitate a new injury. I postulated the relationship of
the subarachnoid hemorrhages and complaints of sciatica.

The pathway for the increased fluid from the results of a bleed in
the subarachnoid space does exist. The circulation of CSF fluid is
postulated to travel from the lateral ventricle through the
intraventricular foramen into the third ventricle and then through
the cerebral aqueduct into the fourth ventricle. Fluid then
travels through the lateral apertures of the fourth ventricle and
the medial foramen of the fourth ventricle into the subarachnoid
space, where it diffuses over the brain and spinal cord.¹

Myelographic examination revealed a mild central canal stenosis at
L4-L5 due to an anterior epidural defect, according to the
radiologist, most likely representing a bulge. In addition,
perineural cysts at L5 and S1 were present. Central stenosis is
additionally noted on MRI with a bulging annulus and hypertrophic
changes at the facet articulations L4-5.

Being a closed system, it would follow that the increased fluid
produced could then cause an increased pressure at an already
compromised area, in our case L4-5 region, increasing sciatic or
nerve root symptoms. In conclusion, although this is a hypothesis
on one clinical episode, it does show the need for a complete
history of the patient is imperative for proper protocol in the
treatment of each patient.

Reference

1. Chusid JG. Correlative Neural Anatomy and Functional Neurology, 16th ed. Lang Medical Publications.

Richard Beck, DC
Danbury, Connecticut