Bronchoscopic Tissue Removal

1
Bronchoscopic Tissue Removal

• Group 7
• Presented by Nathan Killian
• Partners David Jin
• Sangita Sudharshan
• Mentor Martin L Mayse, M.D.
• Director, Interventional Pulmonology
• Washington University in St. Louis

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Lung Obstructions

• Lung cancer is the primary cause
• 175,000 new cases
• 30 will develop symptomatic obstruction
• 98 would die on a ventilator without
  bronchoscopic removal
• Still many problems
• 3

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3
Project Scope

• Design a new bronchoscopic tissue removal device
  to solve the most critical problems existing with
  current devices

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In This Presentation

• Review most common bronchoscopic tissue removal
  techniques
• (results of literature searches)
• Discuss our design requirements based upon the
  problems we found
• Present specifications and preliminary
  mathematical analysis for our device

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Bronchoscopes
16
Flexible
Rigid
6
Bronchoscopic Technique
7
Types of Obstructions
3
Endoluminal Extraluminal Mixed
8
Mechanical Debulking
6
10
16
Rigid Core-out
Forceps Debridement
Suctioning
9
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

1
10
Mechanical Debulking

• Disadvantages
• Poor hemostasis
• Poor limiting of local disease recurrence (short
  durability)
• Takes a long time through a flexible bronchoscope

1
11
Electrocautery
16
12
Argon Plasma Coagulation
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Electrocautery

• Advantages
• Immediate relief of airway obstruction
• Can be used through both rigid and flexible
  bronchoscopes
• Excellent hemostasis
• Fine control over amount of tissue destruction
• Slows local disease recurrence

2
14
Electrocautery

• Disadvantages
• Delayed collateral tissue damage is possible
• Cannot be used for patients with pacemakers and
  automated implantable cardiac defibrillators
• Risk for endobronchial fires, hemorrhages, and
  electrical shock to patients or operators
• Tissue sample cannot be removed

2
15
Cryotherapy
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Cryotherapy

• Advantages
• Can be used through both rigid and flexible
  bronchoscopes
• Excellent hemostasis
• Little risk of injury to neighboring healthy
  tissue
• Slows local disease recurrence

4
17
Cryotherapy

• Disadvantages
• Very slow effect and clearing of airway
  obstruction
• Tissue sample cannot be removed

4
18
LASER Resection
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LASER Resection

• Advantages
• Fine control over amount of tissue destroyed
• Slows local disease recurrence
• Excellent hemostasis
• Quick airway obstruction relief
• Can be used through both flexible and rigid
  bronchoscopes

5
20
LASER Resection

• Disadvantages
• Risk of endobronchial fires if used in an
  oxygen-rich environment
• Risk of airway perforation
• Tissue sample cannot be removed

5
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Brachytherapy
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Brachytherapy

• Advantages
• Can treat deep obstructions
• Potentially curative for inoperable, early stage
  tumors
• Excellent hemostasis
• Can be used through both flexible and rigid
  bronchoscopes

3
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Brachytherapy

• Disadvantages
• Very slow relief of airway obstructions
• Risk of deep tissue destruction
• Tissue sample cannot be removed

3
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Photodynamic Therapy
Pre-Treatment
LASER Application
Post-Treatment
16
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Photodynamic Therapy

• Advantages
• Can be used through both flexible and rigid
  bronchoscopes
• Selective destruction of tumor
• Limits local disease recurrence
• Excellent hemostasis

5
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Photodynamic Therapy

• Disadvantages
• Patients receiving treatment must avoid direct
  sunlight for up to 6 weeks following the
  procedure
• Tissue sample cannot be removed

5
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Summary of Therapy Qualities
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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 Specifications

• 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
• Materials
• Biocompatible (e.g. stainless steel, silicone
  plastic, ABS plastic) 8,9,10
• Reusable (washed and autoclaved)
• Weight consistent with current tools

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More Specs

• Suction must be less than 300 mmHg (max wall
  suction used in hospitals)
• For electrocautery, LASER resection, cryotherapy,
  etc.
• Device must be compatible with common OLYMPUS
  devices used in hospitals

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Preliminary Mathematical Analysis

• Heating of tissue with electrocautery
• Heating of tissue with LASER resection
• Suction pressure to displace tissue

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Heating with Electrocautery

• Set your Argon plasma probe to 15 W

s
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Heating with LASER Resection

• Total absorbed power density Capacity of
  material to conduct heat away from impact site
  Heat absorbed from laser at impact
• K thermal conductivity
• tp duration of irradiation
• p density
• Cv specific heat per unit volume
• (T1-T0) change in temperature
• (1-R) absorption coefficient
• Io laser intensity
• 1460 W/cm2 needed to vaporize biological tissue

13
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Suction Needed to Displace Tissue

• Assume we have a 4 mm long piece of tissue that
  we want to stretch 2 mm

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Project Schedule
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Work Distribution

• Nathan
• Preliminary presentation
• Design focus electronics, energy sources
• Literature and patent searches
• Sangita
• Progress presentation
• Design focus materials
• Safety management
• David
• Final presentation
• Design focus mechanics
• Website development

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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
• Images borrowed from Dr. Mayse

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Questions?