Normal pressure hydrocephalus (NPH) is a pathologic condition whereby excess CSF is retained in and around the brain despite normal intracranial pressure. MRI-safe programmable shunt valves allow for fluid drainage adjustment based on patients' symptoms and radiographic images. Approximately 75% of patients with NPH improve after shunt surgery regardless of shunt type or location.

In this episode, Aaron Berkowitz, MD, PhD, FAAN, speaks with Kaisorn L. Chaichana, MD, author of the article "Management of Normal Pressure Hydrocephalus" in the Continuum® June 2025 Disorders of CSF Dynamics issue.

Dr. Berkowitz is a Continuum® Audio interviewer and a professor of neurology at the University of California San Francisco in the Department of Neurology in San Francisco, California.

Dr. Chaichana is a professor of neurology in the department of neurological surgery at the Mayo Clinic in Jacksonville, Florida.

Additional Resources

Read the article: Management of Normal Pressure Hydrocephalus

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Host: @LyellJ

Guest: @kchaichanamd

Full episode transcript available here

Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about earning CME, subscribing to the journal, and exclusive access to interviews not featured on the podcast.

Dr Berkowitz: This is Dr Aaron Berkowitz, and today I'm interviewing Dr Kaisorn Chaichana about his article on management of normal pressure hydrocephalus, which he wrote with Dr Jeremy Cutsforth-Gregory. The article appears in the June 2025 Continuum issue on disorders of CSF dynamics. Welcome to the podcast, and please introduce yourself to our audience.

Dr Chaichana: Yeah, thank you for having me. I'm Kaisorn Chaichana. I'm a neurosurgeon at Mayo Clinic in Jacksonville, Florida. Part of my practice is doing hydrocephalus care, which includes shunts for patients with normal pressure hydrocephalus.

Dr Berkowitz: Fantastic. Well, before we get into shunt considerations and NPH specifically, which I know is the focus of your article, I thought it would be a great opportunity for a neurologist to pick a neurosurgeon's brain a bit about shunts. So, to start, can you lay out for us the different types of shunts and shunt procedures, the advantages, disadvantages of each type of shunt, how you think about which shunt procedure should be used for which patient, that type of thing?

Dr Chaichana: Yeah. So, there are different types of shunts, and the most common one that is used is called a ventricular peritoneal shunt. So, it has a ventricular catheter, it has a catheter that tunnels underneath the skin and it goes into the peritoneum where the fluid goes from the ventricular system into the peritoneum. Typically, the shunts are in the ventricle because that is the largest fluid-filled space in the brain. Other terminal areas include the atrium, which is really the jugular vein, and those are called ventricular atrial shunts. You can also have ventricular pleural shunts, which end in the pleural space and drain flui into the pleural space. Those are pretty much the most common ventricular shunts. There's also a lumboperitoneal shunt that drains from the lumbar spine, similar to a lumbar drain into the peritoneum. For the lumbar shunts, we don't typically have a lumbar pleural or lumbar atrial shunt just because of the pressure dynamics, because the lumbar spine is below the lung and as well as the atrium. And so, the drainage pattern is very different than ventricular peritoneal which is top to bottom. The most common shunt, why we use the ventricular peritoneal shunt the most, is because it has the most control. So, the peritoneum is set at a standard pressure in the intraabdominal pressure, whereas the ventricular atrial shunt depends on your venous return or venous pressure and your ventricular pleural shunt varies with inspiration and expiration. So, the easiest way for us to control the fluid, the ventricular system is through the ventricular peritoneal shunt. And that's why that's our most common shunt that we use.

Dr Berkowitz: Fantastic. So, as you mention in the article, neurologists may be reluctant to offer a shunt to patients with NPH because many patients may not improve, or they improve only transiently; and out of fear of shunt complications. So, of course, as neurologists, we often only hear about a patient's shunt when there is a problem. So, we have this sort of biased view of seeing a lot of shunt malfunction and shunt infection. Of course, we might not see the patient if their shunt is working just fine. How common are these complications in practice, and how do you as a neurosurgeon weigh the risks against the often uncertain or transient benefits of a shunt in a patient with NPH who may be older and multiple medical comorbidities? How do you think about that and talk about it with patients?

Dr Chaichana: When you hear about shunt complications, most of the shunt complications you hear about are typically in patients with congenital hydrocephalus. Those patients often require several shunt revisions just from either growing or the shunt stays in for a long time or the ventricular caliber is a lot less than some with normal pressure hydrocephalus. So, we don't really see a lot of complications with normal pressure hydrocephalus. So that shunt placement in th