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