Tissue Expander

1
Tissue Expander

• Tissue Expander is an implantable medical device
  used in plastic surgery for the development of
  tissue flaps or reconstruction of tissue defects
  and deficiencies
• The device is placed subcutaneously and implanted
  periodically with sterile isotonic saline until
  the tissue is fully developed.
• The device is removed once the expansion is
  over(6 weeks)

2
Objective

• DEVELOPMENT OF AN
• INDIGENOUS
• CLINICALLY, TECHNICALLY
• AND ECONOMICALLY VIABLE
• TISSUE EXPANDER.

3
Need for Development

• Extremely high cost
• Non-availability
• Reusing tendency

4
Expanders are used in

• Tattoo removal
• Treatment for scar revision
• Correction of an under developed breast
• Post mastectomy reconstruction
• Reconstruction of donor site defects
• Aiding generation of tissue with properties
  similar to donor tissue like color, hair density

5
Tissue expander parts
6
Stages of Evaluation

• Material Evaluation
• Biocompatibility, analytical, mechanical, others
• Invitro Evaluation
• Results found OK, device is safe.
• Clinical Trails
• Proven materials used and encouraging Invitro
  test followed a very limited clinical trial under
  the close supervision of investigating surgeon

7
Raw Materials Used

• Silicone Rubber
• Liquid Silicon Rubber
• Silicone Rubber tubing
• Silicone Adhesive
• Reinforced Silicon Sheet
• Polypropylene
• Polyacetal rods

8
Raw Material Screening

• All basic raw materials which are to be used in
  the fabrication of an implantable device should
  not cause any toxic response in the host, undue
  inflammation of the tissues with which it is in
  contact or migration of any bi-products from the
  device to vital organs.

9
Raw Material Screening contd.

• The material should be free of all heavy metal
  impurities.
• The material should have stable mechanical
  properties so that the variation in the
  performance of the device is minimized.
• Each batch of material has to undergo all the
  specified test

10
Biocompatibility Test(as per USP)

• Systemic Toxicity test
• Intracutaneous Irritation test
• Invitro Haemolysis test
• Intra muscular Implantation test

11
Analytical and Mechanical Test(as per ASTM
standards)

• IR Spectrum
• Volatile Matter
• Vacuum volatiles
• Total extractables
• Tensile Strength
• Elongation at break
• Hardness

12
Other Tests

• Trace Element Analysis
• Antimony, Arsenic, Bismuth, copper, Lead,
  Mercury, Tin, Iron should be less than/equal to
  10ppm
• Dimension
• Silicone tubing ID, OD and concentricity

13
IN PROCESS TESTING(AS PER ASTM F 1441-92)

• Shell(Pouch) Tensile test breaking force
  Tear resistance.
• Tube Shell Junction
• Injection port competence
• Over Expansion
• Tubing Length adapter strength.
• Needle stop penetration.
• Fused or Adhered joints

14
Machinery Used

• Two Roll Mill
• Compression Moulding machine
• Injection Moulding machine
• Ultrasonic cleaner
• Laminar Flow Benches
• Adhesive Dispenser
• Curing Oven
• Mini Lathe
• Blister packing Machine
• ETO sterilizer

15
Unit Operations

• Compounding of Silicon Rubber
• Compression Moulding
• Injection moulding
• Flash cutting
• Connector machining
• Ultra sonic cleaning
• Drying of components
• Assembly of pouch and dome
• In process Testing
• Blister packing
• Sterilization

16
Features of HLL Tissue Expander

• Developed using biocompatible material suitable
  for long term implantation.
• Absence of any metallic part enable trouble free
  CT or MRI scan for the patients
• Muscles of the patient are bound to less strain
  due to the ability of the expander to expand
  differentially