Hydrocephalus is characterized by the abnormal buildup of cerebrospinal fluid (CSF) within the brain’s ventricles. This excess fluid causes the ventricles to expand, putting pressure on the surrounding brain tissue. If left unmanaged, the increase in intracranial pressure can lead to brain damage and can be life-threatening. Treatment aims to relieve this pressure by either diverting the excess fluid or by creating a new pathway for the fluid to flow.
Shunt Placement: The Standard Procedure
The most common method for managing hydrocephalus is the surgical implantation of a cerebrospinal fluid shunt. This medical device diverts excess CSF from the brain to another body cavity where it is safely absorbed into the bloodstream. This procedure is considered a life-saving treatment for many patients.
The shunt system is composed of three main parts: an inflow catheter, a valve mechanism, and an outflow catheter. The inflow catheter is inserted directly into a ventricle of the brain to drain the excess CSF. The valve is situated beneath the skin and regulates the flow and pressure of the fluid, preventing it from draining too quickly or too slowly, which can cause complications.
Many modern shunts feature adjustable pressure valves that allow clinicians to non-invasively change the flow setting after implantation using a magnetic tool. This programming capability eliminates the need for further surgery simply to adjust the valve’s pressure threshold. The outflow catheter carries the fluid to a drainage site, most commonly the peritoneal cavity in the abdomen, resulting in a ventriculoperitoneal (VP) shunt.
Other less common drainage sites include the right atrium of the heart, forming a ventriculoatrial (VA) shunt, or the pleural cavity in the chest. A ventriculoperitoneal shunt is the most frequently used type in both children and adults due to the large absorptive surface area of the peritoneum.
Endoscopic Third Ventriculostomy
An alternative surgical approach is the Endoscopic Third Ventriculostomy (ETV). This procedure is distinct from shunting because it creates a new pathway for CSF flow within the brain, rather than diverting it to another part of the body. ETV is primarily used to treat obstructive, or non-communicating, hydrocephalus.
During the procedure, a neurosurgeon uses a thin, flexible tube called an endoscope, which has a light and a camera, to navigate the brain’s ventricular system. The surgeon makes a tiny opening in the floor of the third ventricle. This new opening allows the trapped CSF to bypass the blockage and flow directly into the basal cisterns, which are fluid-filled spaces at the base of the brain.
The main advantage of ETV is that it does not leave any foreign, permanent hardware in the body, which eliminates the risk of hardware-related complications like infection or mechanical failure. While ETV has become a standard treatment for obstructive hydrocephalus, its success rate varies depending on factors like the patient’s age and the specific cause of the blockage. For patients where ETV is not successful, a shunt placement may still be required.
Long-Term Management and Monitoring
The treatment of hydrocephalus typically involves ongoing long-term management and monitoring, as surgical procedures are often not a one-time cure. Shunt systems, in particular, are prone to eventual malfunction, which requires prompt attention and often a revision surgery. Shunt failure rates are relatively common, with approximately 50% of shunts in the pediatric population failing within two to four years of placement.
Malfunction can occur due to infection, blockage, or mechanical failure, such as a disconnection in the tubing. Symptoms of a malfunctioning shunt can vary widely depending on the patient’s age but generally reflect an increase in intracranial pressure. In infants, this may present as a bulging soft spot (fontanelle), increased head size, or unusual vomiting.
Older children and adults may experience headaches, nausea, lethargy, vision changes, or a decline in school or work performance. Regular follow-up appointments with a neurosurgeon are necessary for surveillance, including the use of imaging like CT scans or MRI to assess fluid buildup and shunt placement.
Supportive Care and Rehabilitation
While surgical intervention addresses the mechanical problem of CSF flow, supportive care and rehabilitation are necessary for the holistic well-being of the patient. Medical management with medications like Acetazolamide or Furosemide may be used temporarily to decrease CSF production. However, these are not considered long-term solutions for chronic hydrocephalus due to potential metabolic side effects.
Post-operative rehabilitation is a frequent component of care, particularly to address residual functional deficits. Physical therapy is often the most common therapy following surgery, focusing on improving gait, balance, and overall mobility. Occupational therapy helps patients regain independence in daily activities, such as dressing and preparing meals, and can address cognitive challenges. Pediatric patients with developmental delays may also require educational support and specialized developmental therapies.