Week 1: Case Studies Flashcards
1
Q
For the HIP metal on metal recall
- What were the adverse outcomes of the case?
- How do you think the biomaterials relates to the design issue?
- How do you think the biomechanics relates to the design issue?
- Take away points?
A
- Metallosis
- You need to ensure that the material is biocompatible
- Need to be aware of forces and loading on the joint. The contact patch caused rubbing at the same point
- Do additional testing
2
Q
Vaginal Mesh
- What were the adverse outcomes of the case?
- How do you think the biomaterials relates to the design issue?
- How do you think the biomechanics relates to the design issue?
- Take away points?
A
1.
- Pain, vaginal bleeding, vagina scarring, difficulty moving, infection.
- Mesh shrunk
- Lower quality of life
- >700 patients affected
- The mesh cannot always be completely removed by revision surgery
- Did 510k, didn’t do clinical trials
2.
- Erosion of mesh
- Mesh contracted and caused pain
3.
- Implant wasn’t patient specific, each patient has different pelvic size.
- Each mesh was placed in a different position and one patient needed surgery because implant moved to bladder wall.
- Biomechanic tests were performed on cadavers, not live case tests (pull out)
- There was a miismatch with loading
4.
- Learning curve for doctors?
- Explant considerations
- Class IIa but should have been Class III
- This works with hernia, but the loads are very different.
- VERIFICATION AND VALIDATION! SHOULDN’T HAVE BEEN ALLOWED TO BE FAST TRACKED.
3
Q
PIP implant
- What were the adverse outcomes of the case?
- How do you think the biomaterials relates to the design issue?
- How do you think the biomechanics relates to the design issue?
- Take away points?
A
1.
- Implants ruptured, leakage, exposure to silicon, patient anxiety.
- Had double the rupture rate.
- Implant had to be removed. Was not replaced.
- Inflamed lymph nodes for all.
2.
- Biocompatible silicon was replaced with industrial silicon
3.
- Medical grade didn’t rupture, industrial silicon ruptured. Difference in strength?
- Loading environment
4.
- Could cost the NHS 100,000,000 pounds
- Regulators could have done more.
- Procedural reinforcement compliant.
- Pip implant inferior design. Biggest problem was non-medical silicon which doesn’t have traceability. Needed to do animal testing.
4
Q
Bio-resorpable Vascular Scaffold
- What were the adverse outcomes of the case?
- How do you think the biomaterials relates to the design issue?
- How do you think the biomechanics relates to the design issue?
- Take away points?
A
1.
- Increases rates of heart attacks and blood clots.
2.
- Stent dissolves after 3 years.
- Patients need to follow antiplatelet therapy.
- After scaffold dissolves, matrix forms from the material. Maybe not enough extracellular matrix was formed.
3.
- It is not recommended to insert the scaffold into vessels that have a diameter <2.5mnm as the balloon is not able to fully inflate
- Not recommended to treat patients that have a lesion that prevents complete inflation of angioplasty balloon. Strongly recommended to achieve residual stenosis between 20-40% after pre-dilation to enable successful delivery and full expansion of scaffold.
4.
- Determine if the patient is suitable before they have the procedure.
5
Q
Vitke Proplast - Teflon TMJ implant
- What were the adverse outcomes of the case?
- How do you think the biomaterials relates to the design issue?
- How do you think the biomechanics relates to the design issue?
- Take away points?
A
1.
- Bone resorption, pain, degeneration of part of the skull
- Fragmentation, perforation and deterioration in high load environment
- Teflon caused inflammatory response leading to severe osteolysis.
2.
- Teflon coating degenerated, causing an inflammatory response and osteolysis.
3.
- Testing wasn’t performed and so manufacturers weren’t aware that fragmentation, perforation, and deterioration occurred in a high load environment
4.
- Animal testing should be performed.
- Lack of research was performed, lack of validation testing.
- Reclassification occurred to class III device.
