Emergency transorbital ventricular puncture: Refinement of external landmarks: Laboratory investigation

Object. Emergency access to the ventricular system is sometimes necessary for the treatment of raised intracranial pressure with ensuing herniation. One procedure described in the literature is a transorbital approach performed using a spinal needle. Because past publications have been case reports with minimal definition of external landmarks, the present study was performed. Methods. Five adult cadavers (10 sides) underwent transorbital puncture of the lateral ventricles. This approach was performed following an axial section through the cranium that exposed the lateral ventricular system. Landmarks for the ideal placement of catheters into the ventricular system were then evaluated. Results. The authors found that the lateral ventricular system was consistently entered just superior to the level of the foramen of Monro by puncturing the roof of the orbit just medial to a midpupillary line, with the trajectory of the perforation aimed 45° from a horizontal line and 15-20° medial to a vertical line. Conclusions. Although it is uncommon, transorbital ventriculostomy may be used in emergency cases of raised intracranial pressure. Such refined landmarks as described in the present study may be of use to the neurosurgeon.