Tissue Recovery

1
Tissue Recovery

• Kathleen Agard
• October 06, 2005

2
Introduction

• History of Allograft Tissue Use
• Processing tissues
• Tissues recovered
• Future Developments

3
History - The beginning

• 800BC Susrata grafting skin for noses
• 1668 - First recorded successful bone graft
• Xenograft- dog skull to human
• cranium.
• Job Van Meeneren of Holland
• 1682- Russian aristocrat,
• excommunication

4
History - Other Developments

• 1800s - successful auto/allograft of skin
• By 1920s - successful bone, skin and cornea
  transplants
• 1960s - 1990s
• Discovery of cyclosporine (immunosuppressive
  drug)
• Cryopreservation of tissue
• Allows preservation with minimal tissue
  destruction

5
History - Modern Demand

• Steady increase tissue transplants
• End of 1980s - 200,000 transplants
• Mid 1990s - 500,000 transplants
• By 2001 - over 1,000,000 transplants
• Why such an increase?
• Aging population
• Improved Technology
• Increased Awareness

6
Common Tissues Recovered

• Bone
• Long bones and hemi pelvis
• Tendons
• Vascular tissue
• Hear valves
• Saphenous vein
• Pericardium
• Skin
• Cornea

7
Obtaining TissuePeople involved
8
Obtaining Tissue Necessary Steps

• Donor, donor family, doctor of deceased
• Living will
• Awareness of recovery options
• Sign informed consent
• Screener
• Obtain informed consent
• Screen donor for acceptability

9
Obtaining TissueNecessary Steps Donor Screening
10
Obtaining TissueNecessary Steps Recovery,
Processing, Receiving

• Recovery team
• Physical exam of body
• Collect, culture and package tissues
• Processing technician
• Serology tests and examine tissue integrity
• process and store tissues
• Tissue recipient and surgeon
• request of tissue

11
Vascular Tissue Grafts

• Cryopreservation
• Rate-controlled freezing
• Long term storage
• Smooth muscle integrity maintained
• Endothelium sometimes compromised
• Smooth muscle and endothelium needed for patency

12
Vascular Tissue Heart Valves

• Uses
• Congenital acquired defects
• May include aortic conduit
• Benefits
• Low risk of anticoagulant therapy
• Allows some flexibility
• Risks
• Compromised endothelium integrity
• Contamination /disease transmission

13
Vascular Tissue - Veins

• Saphenous/femoral vein Uses
• Connection for dialysis
• Vein replacement/ prevents amputation
• Benefits
• Allows blood flow
• Risks
• Contamination /disease transmission
• Reduced patency

www.your-doctor.net/ diabetes/diabetic_pad.htm
14
Skin

• Uses
• Bandage for healing
• Not permanent graft
• Benefits
• Promotes healing
• Helps prevent infection
• Skin from patient/culture for permanent graft

www.burnsurvivorsttw.org/ burns/grafts.html
15
Other Tissues

• Pericardium
• Substitute for Dura Mater
• Eye
• Cornea
• Sclera Reinforces eye wall
• Tendons
• Ligament repair (ACL/PCL)

http//www.thecgroup.com/cimages/
16
Bone Grafts Tissues Recovered
17
Bone Structure
Cancellous Bone
Compact Bone
www.sirinet.net/jgjohnso/ skeletonorg.html
http//www.meddean.luc.edu/lumen/
18
Bone Grafts - Processing

• Devitalize tissue
• Freeze-dried (low temperature and vacuum)
• Freeze/thaw cycles
• Decreases antigen load
• Sterilize tissue
• Gamma irradiation
• Ethylene oxide
• Modify tissue into appropriate form

19
Bone Grafts - Forms Used

• Freeze-dried bone matrix
• Provides structure
• Demineralized freeze-dried bone matrix
• Matrix proteins exposed - promotes healing
• Less structure
• Bone powders/putty/chips
• Mineralized/demineralized
• Autografts may include bone marrow

20
Bone Grafts Promote Healing

• Fills space
• Induction of cell differentiation
• Conduction of cells to damaged area
• How does this happen?

21
Normal Bone Healing
22
Bone Healing Endochondral Ossification
bicmra.usuhs.mil/.../ HTMLdocs/cb13.html
23
Bone Healing Bone Formation and Remodeling
Osteoclast
Osteoblasts
http//www.meddean.luc.edu/lumen/
24
Bone Healing Important Points

• Stabilization needed for endochondral bone growth
• Damaged tissue signals cell differentiation
  (Induction)
• Resorption of cartilage allows for conduction
• Bone can heal without a scar
• Large trauma can result in nonunion

25
Bone Allografts Promote Healing

• Provide structure and stabilize fracture
• Promotes Induction
• Contains proteins signals
• Host cell differentiation (osteoblasts/osteoclasts
  )
• Promotes Conduction
• Graft is reabsorbed
• Cells move into graft with time
• Prevents Non-union (filling space with fibrous
  tissue)
• Note Healing around grafts undergoes a slightly
  different process called creeping substitution.

26
Bone Grafts Uses
Vertebral Fusion

• Cancer
• Trauma
• Vertebral fusion
• Fillers
• Bone putty/powder
• Bone Screw
• Interesting idea
• Puts limit on healing time

www.espine.com/ diagnosis_acf02.html
27
Grafting Options

• Cancellous autograft bone marrow
• Take from calcaneous
• Gold standard
• Allografts (cancellous compact)
• Provide structure
• Osteoinduction osteoconduction
• Synthetic Materials
• Provides structure
• Osteoconduction

28
Bone Allograft Compared to Gold Standard
Autografts
29
Future Improvements

• Detecting Contamination
• Processing Tissues
• Maintaining tissue integrity
• Reducing contamination
• Donor awareness

30
Resources

• Bone Pictute. Sept. 21, 2005. lt
  www.sirinet.net/jgjohnso/ skeletonorg.html gt
• Buckwalter, Joseph, ed. Orthopaedic Basic
  Science. American Academy of Orthopaedic
  Surgeons. 2000.
• Endochondral ossification. October 1, 2005. lt
  bicmra.usuhs.mil/.../ HTMLdocs/cb13.html gt
• Heart picture. October 3, 2005. lt
  http//www.thecgroup.com/cimages/gt
• LUMEN Histology. Sept. 21, 2005
  lthttp//www.meddean.luc.edu/lumen/gt.
• MTF Educational Resources obtained July 20, 2005.
• Saphenous Vein Picture. September 21, 2005. lt
  www.your-doctor.net/ diabetes/diabetic_pad.htm gt
• Skin Picture. September 21, 2005. lt
  www.burnsurvivorsttw.org/ burns/grafts.html gt
• Vertebral fusion. October 3, 2005.
  www.espine.com/ diagnosis_acf02.html
• Wezeman, Fredrick, PhD. Personal Interview.
  Department of Orthopaedic Surgery Loyola
  University Medical School. September 23, 2005.