Presentation on theme: "Hydrocephalus and Neuro Shunting Sales Training April 2001."— Presentation transcript:
Hydrocephalus and Neuro Shunting Sales Training April 2001
Hydrocephalus: From the Greek word hydro (water) & cephalo (head). A pathological condition where there is a disturbance in production, circulation and/or absorption of CSF, with subsequent accumulation of CSF in the fluid-filled compartments of the brain (ventricles).
About CSF (Cerebrospinal Fluid) Clear, colorless fluid Bathes, nourishes & protects brain and spinal cord. Average CSF production-20ml/hr adults and 8ml/hr children 400 to 500cc produced daily contains 15 to 45mg/100ml protein,some glucose, salts, urea and WBC’s
Ventricular System Fluid filled cavities deep in cerebrum w/ pressure of mmH2O Four ventricles 2 Lateral Third Fourth Connected by Foramen of Monro Aqueduct of Sylvius
Choroid Plexus Very vascular Found throughout but mostly in lateral Responsible for ICP waveform/ follows arterial pulse
Brain Layers/CSF Absorption A. - Arachnoid A.G. - Arachnoid Granulation B. - Bone C.A. - Cerebral Artery C.V. - Cerebral Vein D. - Dura Mater F.C. - Falx Cerebri P.M. - Pia Mater S. - Skin S.A.S. - Sub-Arachnoid Space S.D.S. - Sub-Dural Space S.S.S. - Superior Sagittal Sinus
CSF Flow-path CSF flows in a caudal direction through the lateral, third and fourth ventricles Exits through foramina of Luschka and Magendie into subarachnoid space around spinal cord and brain. Absorption occurs through the arachnoid granulations into the venous system.
Types of Hydrocephalus Communicating Non-communicating or Obstructive Normal Pressure Hydrocephalus Congenital Acquired
Normal CT Scan CT Scan Showing severe hydrocephalus
Etiology of Hydrocephalus Communicating Overproduction/underabsorption of CSF Choroid Plexus Papilloma-overproduces CSF SAH Infection Neoplasms affecting the meninges Trauma
Interventions for Hydrocephalus If untreated: *50-60% die of complications If treated: *40% normal intelligence *70% live beyond infancy
Historical Treatment of Hydrocephalous Hippocrates recognizes water accumulation in the brain Thomas Phaire-1st non-surgical treatment--Herbal plasters, head wraps 18th Century--ventricular puncture--death from meningitis common 1800’s-Variety of materials used to “wick” CSF from ventricles to subarachnoid space (i.e., linen threads, glass wool, rubber tube) 1898-first lumboperitoneal shunt
Historical Treatment of Hydrocephalous, con’t 1922-Dandy-third ventriculostomy through subfrontal approach 1923-Mixter-1st endoscopic 3rd Vent., choroid plexectomy (L’Espinasse, Hildebrande, Dandy, Putnam and Scarff) 1950’s-First effective CSF diversion with a one-way valve using biocompatible synthetic materials. John Holter-1st Silicone Valve Robert Pudenz-Silicone distal slit valve Peritoneum chosen as better absorptive site than the vascular system
Heyer Schulte and Shunt Industry History 1953: Dr. Robert Pudenz and W.T. (Ted) Heyer team up on hydrocephalus research 1955: Pudenz ventriculo-atrial shunt is developed 1959: Rudy Schulte joins Heyer and Pudenz 1959: Pudenz flushing valve is developed 1960: Codman distributes Heyer-Schulte products 1960: Holter valve is created 1965: Cordis begins U.S. presence 1965: Extra-Corporeal buys Holter 1973: Codman dropped as Heyer-Schulte distributor
Heyer Schulte and Shunt Industry History 1974: American Hospital Supply buys Heyer-Schulte 1975: Codman introduces their own product line 1977: Anasco, PR manufacturing facility is built 1978: Codman buys Extra-Corporeal 1983: AHS folds Heyer-Schulte into V. Mueller 1984: Dr. Pudenz and Rudy Schulte found P-S Medical 1986: Baxter-Travenol acquires AHS
Heyer Schulte and Shunt Industry History The 90’s NeuroCare Group acquires Heyer-Schulte Radionics introduces full shunt line Medtronic acquires P-S Medical Phoenix Biomedical enters the market Codman acquires Cordis Elekta acquires Cordis NMT acquires Cordis Integra acquires Heyer-Schulte
What is a Shunt? A shunt is a device that diverts CSF from the CNS (usually the lateral ventricle or the lumbar subarachnoid space) to an alternate body cavity (usually the peritoneum or the right atrium) where it is reabsorbed.
How Shunts Work Divert CSF from the CNS to another body cavity (R atrium, peritoneum) for absorption. Mechanical device that regulates flow out of the ventricle. One-way valve opens when the sum of the forces acting on it exceed some threshold. (the difference between the inlet or ventricular pressure and outlet or peritoneal pressure.
Shunt Systems Ventriculo-peritoneal Ventriculo-atrial Lumbar-peritoneal
Valve Mechanisms Differential Pressure Valves Valves open when difference between the ventricular pressure and the peritoneal pressure exceeds some threshold. Pressure difference at which a valve opens is called the opening pressure. Pressure difference at which a valve closes is called the closing pressure.
Valve Types Burr Hole - shaped to fit the hole made in the skull. The reservoir is an integral part e.g. Pudenz Flat Bottom - rests flat against the skull distal to the ventricular catheter e.g. LPV II, Novus Cylindrical/In Line - appears “seamless” between the ventricular and peritoneal catheters e.g.. Ultra VS
Ultra VS Cylindrical
One Piece Hydro Shunt
Internal Valve Components Slit Ball and Spring Miter Diaphragm
Valve Mechanisms Slit Miter
Valve Internal Mechanisms High spring rate valves- open slowly, close quickly (miter, slit) Low spring rate valves- open quickly, close slowly (diaphragm, ball & spring, prone to siphon)
Valve Mechanisms Slit valves - a slit in a curved rubber layer. The flow arriving from the concave side opens slit, size of opening relating to the upstream pressure Can be proximal or distal Disadvantage: ”stickiness” of silicone rubber can affect opening Precision? Varies with age of valve?
Valve Mechanisms Mitre valves - the leaves of the “duckbill” part in response to the pressure differential. Pressure characteristics of mitre valve are related to size,shape, thickness and length of leaves. Disadvantage : “stickiness” of silicone rubber can affect opening
Valve Mechanisms Spring valves/Ball in cone - a metallic spring which applies force to a ball (usually ruby or sapphire) located in an orifice. Opening pressure is defined by spring stiffness Disadvantage: prone to obstruction from CSF debris or high protein content subject to siphoning
Ball-in-Cone Valves Codman Medos Hakim Medos Programmable NMT/Cordis Atlas Hakim Orbis Sigma II Sophysa Sophy Programmable
Valve Mechanisms Diaphragm valves - a round diaphragm rests on or under a valve seat. Pressure causes the diaphragm to be detracted from the seat allowing CSF to flow Disadvantage: prone to siphoning in some designs flow is not laminar making it prone to obstruction
Flow regulating mechanisms Maintains same flow rate at any differential pressure by increasing or lowering its resistance to pressure May be achieved by a solid conical cylinder inserted inside a ring attached to a pressure sensitive membrane Valve Mechanisms
Inner diameter of ring is greater than larger outer diameter of conical cylinder By reducing surface area, mechanism restricts amount of fluid that can go through Outer cylinder moves to compensate for reduced surface area to maintain flow rate. Valve Mechanisms
At very low pressures acts like a DP valve At high pressures the ring moves beyond the central cylinder to give a “blow off” valve. Valve Mechanisms
Treatment for Siphoning In a vertical position, negative pressure from hydrostatic column can cause overdrainage Siphoning control achieved by adding siphon resistive devices to the shunt system. Functions as a second valve in line that closes in response to peritoneal pressure
Shunt Failures and Complications Shunt failure is at a maximum in first few months after surgery (25-40% at one year follow-up). Then falls to 4-5% The mean survival for a shunt is approx 5 years
Shunt Failures and Complications Shunt obstruction (about % of all failures) Infection(between %) Mechanical failure due to disconnection Valve failure Overdrainage Patient/shunt mismatch
Shunt Placement Procedure Skin Incision Placement of Burr Hole Sbcutaneous dissection Tunnel the peritoneal catheter Open dura & place ventricular catheter Connect valve, test & clean Distal catheter insertion & skin closure
Skull of a newborn seen from above Adult human skull seen from above Lamboidal Suture Posterior Fontanelle Sagittal Suture Anterior Fontanelle Metopic Suture Coronal Suture
Indications For Use of a Lumbar-Peritoneal Shunt Communicating Hydrocephalus - when ventricles are small and it would be difficult to cannulate with a ventricular catheter. Normal Pressure Hydrocephalus - shunting without necessitating a cranial procedure.
Goals of Shunt Design & Development Restoration of “normal physiology” in the shunted individual Maximize the potential quality of life for each patient Expand the population of successfully treated patients
First Generation Diaphragm Valve
Second Generation Diaphragm Valve
Third Generation Diaphragm Valve
Integra NeuroSciences Consistency by Design
FLOW PATH DELTA VALVE
LPV II Valve Performance at High Flow Rates (45.8ml/hr) LPV Valve Performance at High Flow Rates (45.8ml/hr)
LPV II Valve Performance at Low Flow Rates (4.6ml/hr) LPV Valve Performance at Low Flow Rates (4.6ml/hr)