Cleanroom assembly
Class 100 laminar flow hoods
STI maintains a certified ISO 7 (US Class 10,000) cleanroom facility. Cleanroom procedures that require a stricter level of cleanliness are performed within ISO 5 (US Class 100) laminar flow hoods. STI closely monitors the cleanroom's temperature, relative humidity, differential pressure and airborne biological contaminants to ensure compliance with ISO 14644 standards.
STI specializes in assembling and packaging medical devices for MIS applications, particularly implants and surgical instruments. STI produces Class II and Class III devices, such as: heterologous tissue-covered stents, cardio-vascular stent kits, laparoscopic and endoscopic surgical tools, liposuction devices for aesthetic plastic surgery, dental balloons for antral membrane elevation and skin graft preparation pallets.
Pericardium covered stent
Biological tissue processing and suturing
STI prepares the chemical solutions used in biological tissue processing and sterilizes them using 0.2µm filtration. The next step involves cutting a bovine or equine pericardium tissue into workable pieces and chemically treating them. The tissue cover is then sewn under microscope on stents or valve frames using surgical sutures. The final product undergoes chemical sterilization, allowing the tissue-covered implant to remain wet, intact and sterile until surgical implantation by a surgeon.
Product assembly methods
Cardiovascular stent kit
Cleanroom technicians assemble medical devices using the following methods:
- Micro-welding - STI applies high-precision laser spot welding, with a minimal spot weld diameter of 40 microns, for micro assembly of miniature metal components. A common application involves welding radiopaque markers onto medical implants to improve their x-ray visibility.
- Adhesive & UV bonding - bonding components made of various materials, such as: plastics, glass, metal and ceramics. STI applies the appropriate bonding adhesive according to the application and the materials.
- Solvent bonding - joining plastic components using an organic solvent (cyclohexanone). STI uses this method primarily for joining PVC tubes and connectors.
- Electro-mechanical assembly - assembling products containing electronic components and mechanical parts.
- Stent crimping - STI provides turnkey solutions for producing complete stent kits including validated crimping process for crimping stents on balloon delivery systems.
- Pressing - applying mechanical pressure on metal components to position or shape them.
Medical packaging – ready for sterilization
STI applies pouch sealing or blister packaging techniques for medical packaging depending on the product and customer specifications. Each packaging run is pre-tested with dye penetration testing and pull testing. STI provides its customers with the expertise and knowledge needed to select an ISO 11607 compliant, medical packaging system suitable for their applications. Common packaging systems utilize: bar sealing, conveyor sealing, pulse sealing, or tray sealing.
Pouch heat sealing
Implants, surgical tools and other medical devices are often sterilized, whereas other devices, such as lower GI irrigation and evacuation systems, rely on the low bioburden of the cleanroom environment to minimize the risk of microbial contamination.
Sterilization methods
Sterilizing medical devices reduces the bioburden down to a safe level without compromising the properties of the device. STI uses outside contractors for sterilizing medical devices by EtO sterilization and gamma radiation.
- Steam autoclave - subjecting the product to heat and pressure by placing the product in a tight container containing purified water heated above the boiling point. STI uses steam autoclave primarily for sterilizing instruments.
- Ethylene Oxide (EtO) gas - toxic gas influx in a closed chamber eliminates microbial contaminants. Medical devices adversely affected by gamma radiation, for example PVC tubes, are often sterilized by EtO.
- Gamma irradiation - exposing the packaged product to a dose of ionizing radiation eliminates microbial contaminants. Advantages include: sterilization of air-tight packages, difficult to reach areas (e.g: inside thin tubular structures).
- Chemical sterilization - immersing biological tissue in chemical sterilants. STI uses this method for sterilizing assembled products that contain pericardium.
- 0.2 micron filtering - fine filtration of prepared solutions that filters out viable particles.