A stereotactic device for rabbits based on mandibular and cranial landmarks

Abstract

The authors have developed a stereotactic device for use in rabbits that uses the plane at the base of the mandible combined with cranial sutures as an anatomical reference. The device was developed for a study designed to evaluate catheters for infection prophylaxis, and this required the implantation of silicone catheters along a reproducible trajectory through the lateral ventricle. Cadaver and atlas studies demonstrated consistent spatial relationships between intracranial structures and the surface plane on which the animals were resting during the surgery. This plane is formed by the 2 mandibular angles and the mandibular tip. The authors developed a stainless steel stereotactic device that uses this mandibular plane as well as the coronal and sagittal sutures as spatial references. Operations were performed in 60 animals using the stereotactic device, and postmortem dissections of the animals' brains demonstrated 78.6% accuracy of the trajectory within a tolerance of deviation of 5 degrees , and 94.6% accuracy within a tolerance of 10 degrees . The accuracy of the trajectory of the last 18 consecutively operated animals was constantly within a tolerance of 5 degrees . The device can be autoclaved and, since it is relatively simple and inexpensive to build, the authors manufactured 3 identical frames and used them alternately to operate under sterile conditions. The fast and pain-free head fixation minimized anesthesia-related risks. The authors' experiences suggest that the device is suitable for ventricular punctures and, dependant on the individual requirements of accuracy, other procedures that require "approximate" stereotactic guidance especially when a series of animals need to undergo operations quickly.