The expansile properties of kryptonite relating to cranioplasty.

Background And Purpose: Since 2009, a synthetic material known as kryptonite has become increasingly utilized during cranioplasty to repair bony defects. It provides bone-like strength and adhesive properties that make it a suitable replacement for bone. However, applications have been observed in the immediate postoperative period that demonstrates an increase in its original volume, giving rise to irregularities in the cranial surface.

Methods: Ten kryptonite samples were reconstituted and allowed to polymerize according to the manufacturer's directions. The kryptonite samples were molded into a cylindrical shape, and they were immersed in 10 graduated cylinders filled with normal saline. Measurements of the rise in saline relative to baseline were taken at 0, 10, 20, 30, 40, 50, and 60 minutes, and then hourly through 5 hours, with the final measurement recorded at 24 hours.

Results: The mean expansion of kryptonite was approximately 49% with an SD of 22%. The bulk of the expansion occurred within the first 2 hours, after which the rate tended to plateau for the remaining 22 hours.

Conclusions: Kryptonite has been touted as an excellent alternative for repairing contour abnormalities manifested in cranioplasty. Given the unpredictability of its expansile properties, the surgeon must take this variability into careful consideration when planning the desired surgical outcome. The results of the current study were communicated with the manufacture. Immediately thereafter, the manufacturer withdrew the product from the US market and is no longer Food and Drug Administration approved for cranioplasty.