Is HTR-PMI A Good Cranial Flap Replacement Method?
Q: Dr. Eppley, My son required a decompressive craniotomy after being injured in a sporting event. His replaced bone flap subsequently got infected and had to be removed. He is now awaiting a second cranioplasty for replacement of his bone flap. Could you provide any insight to titanium versus PMMA and/ or PEEK custom manufactured implants? Any added information would be most appreciated.
A: There are many materials that are available for reconstruction of cranial defects, particularly those in replacement of a lost cranial bone flap. The three you have mentioned are all synthetic materials and will all work when well handled. No one can tell you that one is superior to the other and surgeons will have their own opinions and preferences. All of these materials can be custom fabricated from the patient’s 3-D CT scan to create a near precision fit implant. The one material that has the longest history in cranial reconstruction is a modified form of PMMA known as HTR-PMI. This is a porous material of sintered HTR granules (PMMA-Poly-HEMA) that creates a solid material that is both porous and hydrophilic. These properties allow the material to become ingrown with blood vessels and connective tissue, which always bodes well long-term for any implanted material in the body. There have been over 10,000 cases of HTR-PMI cranial implants placed since 1990 with an impressive history of success and resistance to infection. (in non-irradiated wounds) This would be my choice if I had to have a cranial flap replacement.
Dr. Barry Eppley