ABSTRACT
In communicating hydrocephalus (CH), explanations for the symptoms and clear-cut effective treatments remain elusive. Pulsatile flow through the cerebral aqueduct is often significantly elevated, but a clear link between abnormal pulsations and ventriculomegaly has yet to be identified. We sought to demonstrate measurement of pulsatile aqueductal flow of CSF in the rat, and to characterize the temporal changes in CSF pulsations in a new model of CH. Hydrocephalus was induced by injection of kaolin into the basal cisterns of adult rats (n = 18). Ventricular volume and aqueductal pulsations were measured on a 9.4 T MRI over a one month period. Half of the animals developed ventricular dilation, with increased ventricular volume and pulsations as early as one day post-induction, and marked chronic elevations compared to intact controls (volume: 130.15 +/- 83.21 microl vs. 15.52 +/- 2.00 microl; pulsations: 114.51 nl +/- 106.29 vs. 0.72 +/- 0.13 nl). Similar to the clinical presentation, the relationship between ventricular size and pulsations was quite variable. However, the pulsation time-course revealed two distinct sub-types of hydrocephalic animals: those with markedly elevated pulsations which persisted over time, and those with mildly elevated pulsations which returned to near normal levels after one week. These groups were associated with severe and mild ventriculomegaly respectively. Thus, aqueductal flow can be measured in the rat using high-field MRI and basal cistern-induced CH is associated with an immediate change in CSF pulsatility. At the same time, our results highlight the complex nature of aqueductal pulsation and its relationship to ventricular dilation.
Subject(s)
Cerebral Aqueduct/physiopathology , Cerebral Ventricles/physiopathology , Disease Models, Animal , Hydrocephalus/pathology , Pulsatile Flow/physiology , Analysis of Variance , Animals , Dilatation, Pathologic/cerebrospinal fluid , Dilatation, Pathologic/physiopathology , Female , Hydrocephalus/chemically induced , Hydrocephalus/physiopathology , Imaging, Three-Dimensional/methods , Kaolin , Magnetic Resonance Imaging/methods , Rats , Rats, Sprague-Dawley , Time FactorsABSTRACT
A 15-year-old drummer in a neighborhood rock music band suffered a traumatic true aneurysm of the cervical vertebral artery from violent head and neck motion. He underwent excision of the aneurysm after distal and proximal ligation of the artery. He is neurologically normal 1 year after surgery. The mechanisms of injury caused by extremes of cervical motion, as well as 5 previously reported cases of extracranial vertebral artery aneurysm from closed trauma, are discussed. Excision of vertebral artery aneurysms in patients with emboli from a mural thrombus is recommended. The consequences of vertebral artery ligation and the indications for distal reconstruction are discussed.
