Bronchoscopic Tissue Removal

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Bronchoscopic Tissue Removal

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

2
Overview of Need

• Lung cancer is the primary cause of airway
  obstructions
• 175,000 new cases
• 30 will develop symptomatic obstruction
• 98 would die on a ventilator without
  bronchoscopic removal
• Still many problems with current methods

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Current Methods
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Design Requirements

• Be used in either rigid or flexible bronchoscope
• Minimize collateral damage
• Have an immediate effect
• Control bleeding
• 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 300 mmHg (max wall suction used
  in hospitals)
• Materials
• Biocompatible (e.g. stainless steel, silicone
  plastic, ABS plastic) Reusable (washed and
  autoclaved)
• Weight consistent with current tools

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Current Methods
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Mechanical Debulking

• Advantages
• Fine control over amount/location of tissue
  removed
• Quick relief of airway obstruction
• Can be used through both flexible and rigid
  bronchoscopes
• Tissue sample can be removed
• Will fit well within our budget of 1000
• Simplicity of design
• Disadvantages
• Poor hemostasis
• Short durability
• Surgery is long and tedious
• Solution Automatic Debulking

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Design Alternatives
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1) Linear Hydraulic Saw 1

• Advantages
• Using water (incompressible fluid) as driving
  force can produce a lot of pressure
• Water keeps suction tube clear
• Disadvantages
• Sharp cuts result in poor homeostasis
• Low cutting speed and efficiency

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2) Linear Hydraulic Saw 2

• Advantages
• Using water (incompressible fluid) as driving
  force can produce a lot of pressure
• Water keeps suction tube clear
• Retractile spring does not get in the way
• Disadvantages
• Sharp cuts result in poor homeostasis
• Low cutting speed and efficiency

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3) Linear Electrical Saw With Internal Motor

• Advantages
• Simplicity in design
• Disadvantages
• Micromotors can only deliver 0.1 N of force,
  which is not enough to sheer tissue
• No water to keep suction tube clear
• Sharp cuts result in poor hemostasis
• Low cutting speed and efficiency (10 mm/sec)
• Expensive

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4) Linear Electrical Saw With External Motor

• Advantages
• Able to generate large forces and cutting speeds
• Disadvantages
• No water to keep suction tube clear
• Sharp cuts result in poor hemostasis
• Friction and wear from flexible shaft

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5) Abrasive

• Each of the novel methods described can be
  coupled with an abrasive cheese grater instead
  of a saw.
• Advantages
• Sheering instead of cutting tissue elicits a
  greater inflammatory response due to the greater
  surface area
• This leads to better clotting and hemostasis

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6) Rotary Electrical Sheer Saw

• Advantages
• Sheering good hemostasis
• Good sheering speed and efficiency
• Disadvatages
• Current micromotors cannot produce the require
  torque needed to sheer tissue
• Expensive
• No water to keep suction tube clear

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7) Rotary Pneumatic Sheer Saw

• Advantages
• 300 mmHg of suction pressure able to generate
  enough torque to sheer tissue
• Good cutting speed and efficiency
• Sheering good hemostasis
• Inexpensive
• Disadvantages
• No water to keep suction tube clear

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8) Rotary Hydraulic Sheer Saw

• Advantages
• Incompressible water able to generate enough
  torque to sheer tissue
• Good cutting speed and efficiency
• Sheering good hemostasis
• Water can be used to clear suction tube
• Disadvantages
• Hydraulic system can be expensive

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Pugh Chart
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Rotary Hydraulic Sheer Saw

• Rotating blades will provide at least 12 N Blades
  will be made of stainless steel
• Suction tube will be made of PEEK plastic which
  is flexible and non-deformable under high
  pressures
• 300 mmHg of suction will be applied
• Total diameter 2.2 mm
• Total length 60 cm

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Updated Design Schedule
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Team Responsibilities

• David Jin
• Progress presentation
• Design focus mechanical design of tip and shaft
• Website development
• Nathan Killian
• Preliminary presentation
• Design focus actuating mechanism
• Literature and patent searches
• Sangita Sudhanshan
• Final presentation
• Design focus materials
• Safety management/DesignSafe Analysis

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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.
• Mathur, PN, et. al., Fiberoptic bronchoscopic
  cryotherapy in the management of tracheobronchial
  obstruction, Chest, 1996(110) 718-723.
• Simoff, Michael J., Endobronchial Management of
  Lung Cancer, Cancer Control, 2001(84)337-343.
• http//www.tobacco-facts.info/bronchoscopy.htm
• http//caonline.amcancersoc.org/cgi/reprint/55/1/1
  0.pdf
• http//en.wikipedia.org/wiki/Silicone
• http//www.sdplastics.com/abs.html
• http//www.escomedical.com/
• http//www.chestjournal.org/cgi/content/full/116/5
  /1403
• http//www.medscape.com/viewarticle/455720_10
• http//www.chestjournal.org/cgi/content/full/120/3
  /934
• http//www.engineeringtoolbox.com/specific-heat-ca
  pacity-food-d_295.html
• http//www.medscape.com/viewarticle/489484_print

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Questions?