Cerebrospinal fluid diversion is one of the most frequent neurosurgical procedures across the world and can be challenging in select patients who fail standard distal drainage sites.
The most common procedure to manage hydrocephalus is a ventriculoperitoneal shunt. Other alternatives include a ventriculoatrial shunt, ventriculopleural shunt, lumboperitoneal shunt, or ventriculocisternal shunt.
Cerebrospinal fluid (CSF) shunt procedures have dramatically reduced the morbidity and mortality rates associated with hydrocephalus. However, despite improvements in materials, devices, and surgical techniques, shunt failure and complications remain common and may require multiple surgical procedures.
Understanding the altered physiology following cerebrospinal fluid (CSF) diversion in the setting of adult hydrocephalus is important for optimizing patient care and avoiding complications. There is mounting evidence that the cerebral venous system plays a major role in intracranial pressure (ICP) dynamics especially when one takes into account the effects of postural changes, atmospheric pressure, and gravity on the craniospinal axis as a whole. An evolved mechanism acting at the cortical bridging veins, known as the “Starling resistor,” prevents overdrainage of cranial venous blood with upright positioning. This protective mechanism can become nonfunctional after CSF diversion, which can result in posture-related cerebral venous overdrainage through the cranial venous outflow tracts, leading to pathological states. A review article summarizes the relevant anatomical and physiological bases of the relationship between the craniospinal venous and CSF compartments and surveys complications that may be explained by the cerebral venous overdrainage phenomenon 1).
In patients with a known history of psychiatric co-morbidities-and particularly those patients with prior suicide attempts-the neurosurgeon should give serious consideration to placing the shunt system in an anatomical region which is difficult for the patient to self-access based upon their handedness 2).