Hydrocephalus and Neuro Shunting

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Hydrocephalus and Neuro Shunting

• Sales Training
• April 2001

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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).
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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
  WBCs

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Ventricular System

• Fluid filled cavities deep in cerebrum w/
  pressure of 120-180mmH2O
• Four ventricles
• 2 Lateral
• Third
• Fourth
• Connected by
• Foramen of Monro
• Aqueduct of Sylvius

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• Choroid Plexus
• Very vascular
• Found throughout but mostly in lateral
• Responsible for ICP waveform/
• follows arterial pulse

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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
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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.

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Types of Hydrocephalus

• Communicating
• Non-communicating or Obstructive
• Normal Pressure Hydrocephalus
• Congenital
• Acquired

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CT Scan Showing severe hydrocephalus
Normal CT Scan
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Etiology of Hydrocephalus

• Communicating
• Overproduction/underabsorption of CSF
• Choroid Plexus Papilloma-overproduces CSF
• SAH
• Infection
• Neoplasms affecting the meninges
• Trauma

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Etiology of Hydrocephalus

• Non-Communicating (Obstructive)
• Aqueductal Stenosis
• Arnold-Chiari Malformation (Cerebellar tonsils
  protrude into Foramen Magnum)
• Cysts
• Myelomeningocele
• IVH
• Tumors (particularly posterior fossa)

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Normal Pressure Hydrocephalus

• Usually present in elderly
• Ventricular dilation despite normal CSF pressure
• Triad of symptoms
• 1) dementia
• 2) gait disturbances (usually earliest)
• 3) urinary incontinence

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Signs Symptoms Associated with Hydrocephalus

• Infants
• Increased head size
• Bulging Fontanels
• Separation of Cranial Sutures
• Prominent Scalp Veins
• Persistent Vomiting
• Lethargy or irritability
• Setting Sun eyes
• Seizures
• Delayed Development

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S/S Associated with Hydrocephalus, cont.

• Toddlers
• Increased head size
• Persistent vomiting
• Headache
• Lethargy or irritability
• Setting Sun eyes
• Blurred Vision
• Seizures
• Delayed Development

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Hydrocephalus

• SETTING SUN EYES

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S/S Associated with Hydrocephalus, cont.

• Older Children Adults
• Persistent Vomiting
• Headache
• Visual Problems
• Lethargy
• Behavior Changes
• Difficulty with schoolwork
• Seizures

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Diagnosis

• Clinical Evaluation
• Ultrasound (Intrauterine through Fontanels.
• CT Scan
• MRI

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Treatment Modalities

• Surgical Procedures
• Remove obstruction (Blood Clots, Tumors)
• Endoscopic Third Ventriculostomy
• Septal Fenestrations (Endoscopic)
• Cyst Fenestrations (Endoscopic)
• Shunt Insertion

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Interventions for Hydrocephalus

• If untreated
• 50-60 die of complications
• If treated
• 40 normal intelligence
• 70 live beyond infancy
  
  
  

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Questions???
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Historical Treatment of Hydrocephalous

• Hippocrates recognizes water accumulation in the
  brain.
• 1545-Thomas Phaire-1st non-surgical
  treatment--Herbal plasters, head wraps
• 18th Century--ventricular puncture--death from
  meningitis common
• 1800s-Variety of materials used to wick CSF
  from ventricles to subarachnoid space (i.e.,
  linen threads, glass wool, rubber tube)
• 1898-first lumboperitoneal shunt

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Historical Treatment of Hydrocephalous, cont

• 1922-Dandy-third ventriculostomy through
  subfrontal
• approach
• 1923-Mixter-1st endoscopic 3rd Vent., choroid
  plexectomy
• (LEspinasse, Hildebrande, Dandy, Putnam
  and Scarff)
• 1950s-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

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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

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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

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Heyer Schulte and Shunt Industry History

• The 90s
• 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

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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.

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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.

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Shunt Systems

• Ventriculo-peritoneal
• Ventriculo-atrial
• Lumbar-peritoneal

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Shunt Components

• Primary Components
• Proximal Catheter
• Valve (Proximal or Distal)
• Distal Catheter
• Optional Components
• Reservoir
• Siphon Limiting Mechanism (ASD, SCD, GCD)
• Accessories
• Connectors
• Guides
• Introducers/Stylets
• Catheter Passers

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SHUNT ACCESSORIES

• Proximal catheter stylet (can use endoscope)
• Stylets for unitized shunts
• Shunt passers
• Connectors and Right angle guides
• Shunt tap kits
• Manometers

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Valve Mechanisms

• Differential Pressure Valves
• Flow regulating devices

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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.

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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

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Pudenz
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Mishler Dual-Chamber
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Ultra VS Cylindrical
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One Piece Hydro Shunt
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Ommaya
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Internal Valve Components

• Slit
• Ball and Spring
• Miter
• Diaphragm

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Valve Mechanisms
Slit
Miter
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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)

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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?

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Slit Valves

• Codman
• Holter (proximal catheter/valve)
• Denver (proximal catheter)
• Accuflo (distal catheter)
• Uni-shunt (distal catheter)
• Radionics
• Proximal slit valve
• Phoenix
• Holter-Hausner valve

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One Piece Hydro Shunt
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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

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Mitre Valves

• Heyer-Schulte
• Ultra-VS(cylindrical)
• Mishler Dual Chamber (flat bottom)
• Spetzler in-line Lumbar - Peritoneal valve
  (cylindrical)

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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

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Ball-in-Cone Valves

• Codman Medos Hakim
• Medos Programmable
• NMT/Cordis
• Atlas
• Hakim
• Orbis Sigma II
• Sophysa
• Sophy Programmable

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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

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Diaphragm Valves

• Heyer-Schulte
• Pudenz (burr hole)
• LPV II (flat bottom)
• Novus (flat bottom)
• PS Medical/Medtronic
• Delta (Burr hole, flat bottom)
• Button(flat bottom)
• Contour (flat bottom)

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Diaphragm Valves

• Radionics
• Contour Flex
• Equi-flow
• Burr hole
• Codman
• Accu-flo valve

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Valve Mechanisms

• 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

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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.

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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.

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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

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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

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Shunt Failures and Complications

• Shunt obstruction (about 50 - 60 of all
  failures)
• Infection(between 5 - 10)
• Mechanical failure due to disconnection
• Valve failure
• Overdrainage
• Patient/shunt mismatch

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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

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Shunt Implantation Approaches
Occipital Approach
Temporal Approach
Frontal Approach
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Metopic Suture
Coronal Suture
Anterior Fontanelle
Sagittal Suture
Posterior Fontanelle
Lamboidal Suture
Adult human skull seen from above
Skull of a newborn seen from above
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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.

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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

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First Generation Diaphragm Valve
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Second Generation Diaphragm Valve
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Third Generation Diaphragm Valve
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Integra NeuroSciencesConsistency by Design
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FLOW PATH
DELTA VALVE
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LPV II Valve Performance at High Flow Rates
(45.8ml/hr)
LPV Valve Performance at High Flow Rates
(45.8ml/hr)
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LPV II Valve Performance at Low Flow Rates
(4.6ml/hr)
LPV Valve Performance at Low Flow Rates (4.6ml/hr)
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Competitive Matrix

• Medtronic P.S. Medical
• Cordis
• Codman
• Radionics
• Sophysa
• Phoenix

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Flat Bottom Diaphragm Competitive Matrix
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Flat Bottom Diaphragm Competitive Matrix
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Burr Hole Diaphragm Competitive Matrix
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Neonatal Valve Systems Competitive Matrix
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Product line strengths

• Consistency and predictability
• Broad product line
• Clnical support
• History
• Manufacturing expertise
• Pricing flexibility