Bronchoscopic Tissue Removal Device

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Bronchoscopic Tissue Removal Device

• Group 7
• Sangita Sudharshan
• Nathan Killian
• David Jin
• Mentor Dr. Martin L Mayse

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Overview of Need

• Lung cancer is the primary cause of airway
  obstructions
• 175,000 new cases
• Current methods have several problems

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Current Methods
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Design Requirements

• Be used in a flexible bronchoscope
• Minimize collateral damage
• Control bleeding
• Have an immediate effect
• Recover specimens
• Have a durable effect (gt 1 month)
• Cost less than 1,000 to make

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Design Specification

• Flexibility is primary consideration
• Diameter
• Less than 2.2 mm ideal for 5 mm scope
• 2.2 2.8 maximum for 6 mm scope
• Length
• At least 60 cm working length
• Suction
• Must be less than or equal to 300 mmHg (max wall
  suction used in hospitals)
• Materials
• Biocompatible (e.g. stainless steel, silicone
  plastic, ABS plastic)

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Mechanical Debulking

• Advantages
• Fine control over amount/location of tissue
  removed
• Quick relief of airway obstruction
• Tissue sample can be removed
• Disadvantages
• Poor hemostasis
• Short durability
• Surgery is long and tedious
• Solution Automatic Debulking

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Overview of Chosen Design
Not shown Handle and pumps
Catheter Tubing
Blade
Pin
Hull
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Mathematical Calculations for Design
Specifications

• Pelton wheels normally work at 60-90 efficiency-
  one of the most efficient turbines
• Striving for optimal efficiency, we found that
  this was achieved when using a saline jet
  diameter of 0.2mm, and fluid flow of

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Mathematical Calculations for Design
Specifications
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Mathematical Calculations for Design
Specifications

• Solving for torque
• Net efficiency with this torque

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Mathematical Calculations for Design
Specifications

• Rotations per minute
• Power Output per rotation

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Components of Chosen Design
PEEK tubingstainless-steel nozzle
Stainless-steel Hull
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Components of Chosen Design
Suction Trap connected to Handle
Pelton Wheel Blades
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Material

• Hull, Wheel, Nozzle, and Handle
• Stainless steel 440C
• Biocompatible
• Used in many surgical instruments as well as in
  knives
• Easily machinable
• Pin
• Bronze
• Soft to compliment the hard stainless-steel to
  decrease frictional forces

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Material

• Tubing for suction and saline solution transport
• PEEK(commercial grade)
• Biocompatible, flexible, strong
• Easily extrudable
• Density of 1300 kg/m3
• High tensile strength (good for press-fitting) of
  
• st 90MPa

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Material

• Pump
• High-Pressure Peristaltic Pump-1045
• Isolates saline solution from pumping mechanism
  to maintain sterility
• Produces pressures up to 100psi
• Produces flow rates of 7x10-6 m3/s
• Standard Wall Suction-provided

High-Pressure pump system 970-1500
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Manufacture

• PEEK catheter tubing will be customized using
  extrusion to allow for separate saline and
  suction tubes
• Dimensions
• Length1m
• Saline channel diameter 0.6mm
• Suction channel diameter 1.8mm (horseshoe shape)
• Weight 0.0031 lb
• Cost
• Setup, run, cleanup 1800
• Tooling 568 one time fee
• Material 48/lb 0.0031 lb0.15/tube
• Lead time 2-3 weeks
• (quote from Precision Extrusion)

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Manufacture

• PEEK external tubing will be customized using
  extrusion
• Dimensions
• Length 20cm
• Outer Diameter 3.175mm (saline), 9.525mm
  (suction)
• Wall thickness of 0.2mm
• Weight 0.000185 lb (saline), 0.000566 lb
  (suction)
• Cost
• Setup, run, cleanup 1800
• Material 48/lb0.000185 lb0.009/tube (saline)
• 48/lb0.000566 lb0.027/tube (suction)
• Lead time 2-3 weeks
• (quote from Precision
  Extrusion)

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Manufacture

• The stainless-steel hull, nozzle, Pelton wheel,
  handle, and bronze pin will be machined using CNC
  (Computer Numerical Control) to allow for precise
  machining with very close tolerances
• Hull Dimensions
• overlap with PEEK 0.5cm length, 1.8mm OD, 0.1mm
  thickness
• Window section 2mm OD, 0.2mm thickness
• Nozzle Dimensions
• 45 degree angle
• 0.2mm end diameter
• Wheel Dimensions
• 1.5mm diameter
• Buckets0.5mm diameter total
• Handle Dimensions
• 10cm long
• Holes on external side 1/8 and 3/8
• Hole on catheter side same as catheter tubing
  dimensions
• Stainless Steel Cost 300 (setup/cleanup),
  0.50 per piece
• Lead Time 2-3 weeks
• 
  (estimates from Ohio Laser and Shaw
  Stainless)

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Manufacture

• Pin Dimensions
• Cylinder 2mm long
• 0.2mm diameter
• Bronze Pin Cost 1.00 per piece
• Lead Time 2-3 weeks

(estimates from Ohio Laser and Shaw Stainless)
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Connectors

• Peristaltic pump will connect to plastic tubing
  through 1/8 male Luerlock connector
• Provides tight connection without fluid leakage
• Off the shelf lead time is only shipping time
• Price 12.45 from smallparts.com
• Suction pump will connect to plastic tubing
  through 3/8 barbed connector with thread of ¼
  NPT
• This is the standard connector for hospital wall
  suction
• Off the shelf lead time is only shipping time
• Price 1.99 from manuf. Sierra

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Manufacture Process

• Stainless-steel handle will press-fit to plastic
  tubing
• Handle will press-fit to the PEEK catheter tubing
• Stainless-steel hull and nozzle will press-fit to
  the PEEK catheter tubing
• The wheel will be placed through the suction
  channel and will be held in place with the bronze
  pin
• Bronze pin will fit into drilled hole at the hull
  and will be secured using sealant fit for
  stainless-steel

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Total Cost per Unit

• Maximum of 150 units manufactured/day
• Initial costs
• 1800 X 3 5400 for setup/run/cleanup of each
  PEEK extruded part (3 parts total)
• 568 for PEEK extrusion tooling
• 300 for setup/run/cleanup of metal machining
• Costs per unit
• (0.15 0.009 0.027) X 150 units 28 for
  PEEK parts
• 0.50 X four steel parts/unit X 150 units 300
  for steel parts
• 1.00 X 150 units 150 for bronze pins
• (12.45 1.99) X 150 units 2166 for
  connectors
• Total cost for 150 units 8912
• Cost per unit 60

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Safety Analysis

• DesignSafe output
• Our greatests risks were cutting/shearing/puncturi
  ng tissue and loss of control
• Most possible hazards were eliminated through
  design modifications by adding stainless-steel
  hull to protect wheel from exposure to unwanted
  tissue, and making sure the device was
  light-weight
• Other hazards will be eliminated through
  on-the-job training and physician experience with
  the device

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Satisfies Requirements?

• Minimize collateral damage has only small window
  for blade to shear tissue allowing localization
• Have an immediate effect shearing removes tissue
  immediately
• Time efficient rpmgt600,000 will allow for rapid
  tissue removal
• Control bleeding-shearing at high rpm activates
  more platelets to clot blood
• Recover specimens suctionsaline solution carry
  sheared tissue to suction trap
• Have a durable effect (gt 1 month) more precise
  shearing
• Inexpensive Unit cost 60.00

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Satisfies Specifications?

• Flexible?
• Diameter less than 2.2mm?
• Length at least 60 cm working length?
• Suction 300 mmHg (max wall suction used in
  hospitals)?
• Materials biocompatible?
• Force sufficient to shear tissue?

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IP?

• Our device could be patentable
• We use a novel idea of designing a surgical
  instrument that utilizes saline solution as the
  actuating mechanism, as a lubricant, and as a
  clearing solution

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References

• Prakash, U., Advances in Bronchoscopic
  Techniques., American College of Chest
  Physicians, 1999(116) 1403-1408.
• Ernst, A., et. al., Interventional Pulmonary
  Procedures., American College of Chest
  Physicians., 2003(123) 1693-1717
• Leh, S., Mayse, M., Role of Interventional
  Pulmonology., Washington University in St. Louis.
• http//www.barnant.com/products.php?product5
• Shaw Stainless-http//www.stainlessandalloy.com/
• Ohio Laser-http//www.ohiolaser.com
• Precision Extrusion-http//www.precisionextrusion.
  com
• http//en.wikipedia.org/wiki/Press_fit
• http//circ.ahajournals.org/cgi/content/full/98/8/
  742
• http//www.rit.edu/rfaite/courses/tflab/Cussons/p
  elton/pelton.htm
• http//www.blackwellpublishing.com/xml/dtds/4-0/he
  lp/10003420_chapter_1.pdf

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Questions?