An 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.

Use of three infusion pumps for postoperative administration of buprenorphine or morphine in dogs.

Results of using an implantable osmotic pump, a preset disposable infusion pump, or a reusable programmable infusion pump for postoperative administration of buprenorphine or morphine in dogs undergoing abdominal surgery are described. Ten dogs underwent abdominal surgery for implantation of vascular access ports. Dogs were given buprenorphine s.c. by use of an implantable osmotic pump (4 dogs), morphine s.c. by use of a preset infusion pump (4), or buprenorphine intra-arterially by use of a programmable infusion pump (2). Dogs were monitored, and serum buprenorphine or morphine concentration was measured for 72 hours after surgery; pumps were removed 48 hours after surgery. Severity of pain was determined by assigning a pain score. The preset infusion pump and the programmable infusion pump resulted in comparable pain relief and sustained serum analgesic concentrations throughout the recovery period. However, the cost of the pumps and other associated factors may limit their use to dogs undergoing invasive surgical procedures expected to result in substantial postoperative pain. The level of analgesia obtained with the implantable osmotic pumps was inconsistent.