Proceedings of the 11 th Brazilian Congress of Thermal Sciences and Engineering -- ENCIT 2006 Braz. Soc. of Mechanical Sciences and Engineering -- ABCM, Curitiba, Brazil,- Dec. 5-8, 2006 Paper CIT06-811 AN APPARATUS FOR TESTING EXTERNAL SHUNTS UTILIZED IN HYDROCEPHALUS SURGERY TREATMENT José Ricardo Camilo Ventura Biomédica, São José do Rio Preto,SP, Brazil. camilo@venturaneuro.com.br Angelo L. Maset INNEURO - Instituto de Neurocirurgia e Neurociências do Oeste Paulista, São José do Rio Preto, Brazil, maset@venturaneuro.com.br Kleber Paiva Duarte INNEURO - Instituto de Neurocirurgia e Neurociências do Oeste Paulista, São José do Rio Preto, Brazil, Brazil, kleberduarte@uol.com.br Sérgio Said Mansur Unesp – Faculdade de Engenharia de Ilha Solteira, Ilha Solteira, SP, Brazil. mansur@dem.feis.unesp.br Edson Del Rio Vieira Unesp – Faculdade de Engenharia de Ilha Solteira, Ilha Solteira, SP, Brazil. delrio@dem.feis.unesp.br Abstract. The watery solution continually produced inside the brain in the choroid plexus tissues is named cerebrospinal fluid (CSF). Humans are estimated to produce about 0.5 ml/kg per hour, or about 500 ml or more of CSF each day. A discrepancy in CSF production and absorption cumulates an excess of fluid in the brain. Elevated levels of CSF are associated with traumatic brain injury, meninge infections (meningitis) and a pediatric disease known as hydrocephalus. In all of these cases, an increasing fluid pressure (intracranial pressure), resulting in permanent brain injury and death, can be observed. Following the diagnosis of hydrocephalus, there are few options other than surgery for treatment. Most surgeons use various types of systems called shunts to channel the fluid from the ventricles to other sites in the body such as the abdominal cavity (internal shunts). Liquor can also be drained towards an external reservoir (external shunts). In the present work an apparatus operating as bench test has been developed for testing external shunts. Utilizing automated control and data acquisition system, in order to realize the experiments, hydrodynamics characteristics of several shunts parts can be rapidly obtained. Some first results from a first prototipe of an anti- siphon valve are included. Keywords. External shunt, cerebrospinal fluid, hydrocephalus, neurosurgical devices. 1. Introduction The watery solution continually produced internal the brain in choroid plexus tissues is named, in medical literature, liquor or cerebrospinal fluid (CSF). The CSF flows through a series of cavities (ventricles) out of the brain and down along the spinal cord. The brain and spinal cord float in a sea of cerebrospinal fluid within the skull and spine. Additionally, brain and spinal cord are covered by a series of membranes called meninges. Humans are estimated to produce continually about 0.5 ml/kg per hour, or approximately 500 ml or more of liquor each day. In an adult, in normal conditions, 150 ml of CSF have been estimated at any given time located in the brain ventricles. A discrepancy in CSF production and absorption cumulates an excess of fluid in the brain. Elevated levels of CSF are associated with traumatic brain injury, meninge infections (meningitis) and a pediatric disease known as hydrocephalus. In all of these cases, an increase fluid pressure (intracranial pressure – ICP) can be observed resulting in permanent brain injury and death. If diagnosis of hydrocephalus has been obtained there are rarely options other than surgery for treatment. If a definable mass is causing the obstruction of flow it may be possible, if not essential, to remove the mass and allow for normal flow and resolution of the hydrocephalus. More often then not however, the blockage can not be removed and the fluid needs to bypass the normal circulation. Most surgeons use various types of systems called shunts to channel the fluid from the ventricles to other sites in the body such as the abdominal cavity (internal shunts). Liquor drainage can be realized also for an external reservoir (external shunts). In accord to Sesay et al. (2002), the external drainage of CSF has been realized only in emergency situations and frequently external drainage is a provisory condition after the surgery to implant semi permanent internal drainage device. A sketch of an external device for CSF drainage has been shown in Fig. 1. External reservoir is submitted to atmospheric pressure (Patm) and the height H should be carefully determined by surgeon. ICP should overpass the height H to produce drain effect. If height H is very small or negative