Alternative Method of Chronic Cerebrospinal Fluid Collection via the Cisterna Magna in Conscious Rhesus Monkeys

Models of chronic cerebrospinal fluid (CSF) collection previously have been established for nonhuman primates and canines; many of these methods implement stainless-steel cannulas into the lateral or 4th ventricles or catheters into the cerebral or spinal subarachnoid space. These models have proved successful and reliable but unfortunately require invasive techniques to pass through the skull or require a laminectomy to enter the spinal subarachnoid space, involve the use of expensive and highly specialized stereotaxic equipment for the precise placement of the implants, and may require exteriorized hardware which is cumbersome to maintain and unaesthetic. The model we developed for the rhesus monkey allows for direct access to CSF outflow from the cisterna magna by using a 3.5-French fenestrated silicone catheter which was placed 1.0 cm into the cisterna. The catheter was attached to a titanium port placed subcutaneously between the scapulae to permit easy access for sampling CSF in a conscious, chaired rhesus monkey. We currently have instrumented animals from which we have consistently collected CSF for over 18 months. This novel, economical, less-invasive method permits chronic, reliable collection of CSF in conscious rhesus monkeys and has the additional advantages that the model is easier to maintain and more aesthetic.