Lutz Lab

Department of Bioengineering, University of Washington

 

Development of a smart devices to treat hydrocephalus (current projects with Dr. Sam Browd)

hydrocephalusNPHFig1We all produce cerebrospinal fluid (CSF) at a rate of about a pint a day, and most of us naturally reabsorb CSF in a delicate balance that maintains a moderate fluid pressure in the brain (intracranial pressure, ICP). Hydrocephalus is the inability to the reabsorb CSF, which leads to buildup of pressure in the brain that causes permanent brain injury and is deadly if left untreated. The images at left show the enlarged head typical of pediatric hydrocephalus and images of normal and enlarge ventricles from MR imaging.

 

Hydrocephalus is one of the most common birth defects (1 in 500 live births) but can arise at any stage of life due to trauma, infection, brain tumors, or natural aging. Treatment for hydrocephalus has remained essentially unchanged since its inception in the 1950’s and consists of the implantation of a “shunt” that consists of a pressure valve and drainage tube (a “shunt”) that passes from the brain under the skin to a location in the body where fluid can be reabsorbed (typically the abdominal cavity).

 

shunt design trialHydrocephalus is almost always a life-long condition, so shunts have a long-term responsibility to function without failure. But, shunts fail at an alarming rate – 40% fail within two years, and 98% fail within 10 years [Browd, et al] – due to in large part to catheter or valve obstructions (figure at left shows causes of failure, [Kestle, et al]). Obstruction in existing shunts occurs at the proximal catheter (in the brain, 60%) or at the valve (30%), and over-drainage can cause life-threatening hemorrhage (subdural hematoma), as well as collapse of the brain ventricle onto the proximal catheter (which further exacerbates proximal catheter obstruction by tissue in-growth). Patients with shunts can often lead normal lives, except that they must live with the near certainty that their shunt will fail.

 

Shunt design is in its crudest form a plumbing problem, with most shunt designs acting nominally as pressure regulators. We are applying simple fluidic principles to develop a smart shunt that is designed to be failure-resistant and is capable of detecting problems if they occur.

 

To support translation to patients, Dr. Browd and I started a company, Aqueduct Neurosciences, to commercialize a series of products for cerebrospinal fluid drainage. The experience has taught me to appreciate the non-technical barriers (regulatory, reimbursement, intellectual property) that must be considered to translate ideas into patient care. This in turn allows me to teach our students about this process.

 

References:

·        Lutz, Venkataraman, & Browd. “New and Improved Ways to Treat Hydrocephalus: pursuit of a smart shunt,” Invited review in Surgical Neurology International (2013), 4, Suppl S1:38-50, DOI: 10.4103/2152-7806.109197.

·        Browd SR, Ragel BT, Gottfried ON, Kestle JR: Failure of cerebrospinal fluid shunts: part I: Obstruction and mechanical failure. Pediatric Neurology 34:83-92 (2006).

·        Browd SR, Gottfried ON, Ragel BT, Kestle JR: Failure of cerebrospinal fluid shunts: part II: overdrainage, loculation, and abdominal complications. Pediatric Neurology 34:171-176 (2006).

·        Kestle J, Drake J, Milner R, Sainte-Rose C, Cinalli G, Boop F, et al: Long-term follow-up data from the Shunt Design Trial. Pediatric Neurosurgery 33:230-236 (2000).

 

Sponsors:

http://depts.washington.edu/gwach/sites/default/files/WHCFlogo.jpg  Center for Comercialization  Washington Research Foundation  LSDF_logo_2c.jpg  https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcR26ksyq7F8FRhkE06SBpIyhuqpwwwlEzcFPwBWtPpIoVjXYxHG

UW spin-out company:

http://www.aqueductneurosciences.com/uploads/1/4/6/1/14616906/2114442.png