Measured sternal vibration transmittance data from mockups and cadavers

Stability of bone splitting sternotomy is essential for normal healing after open cardiac surgery. Mechanical vibration transmittance may offer a means for early detection of separation of bone (diastasis) in the sternotomy and prevent further complications. An in-house built measurement system consisting of actuator, sensor, and main controller unit was designed and manufactured for clinical purposes. Three different test settings were studied in mockups (polylactide rods in ballistic gel) and in two human sterni: intact, stable wire fixation, and unstable wire fixation with a gap mimicking bone diastasis. The transmittance of vibration stimulus across the median sternotomy was measured. The technical solution is given. The vibration transmittance response to material cut and sternotomy was evident and detectable in the 20Hz - 2kHz band. The transmittance decreased 23% - 75%, 70% - 97%, and 61% - 89% in intact→stable, intact→unstable, and stable→unstable respectively.