Postoperative sternal stability assessed by vibration: a preliminary study.

Abstract

Mechanical stability of the postoperative sternum was assessed using novel analysis based on vibration response. The response to controlled vibration in the 50 Hz to 1,500 Hz range was studied in 22 elective cardiac surgical patients with an accelerometer, recorded, and processed on a personal computer. Each patient had four measurement sessions. The mechanical transfer function of the sternum was estimated, and several descriptive factors were extracted from it to determine how they reflect changes occurring in the bone during the recovery from sternotomy. Complete datasets were obtained from 14 patients. The most informative variable for the sternal healing was the P(600-1500) index, which reflects transmittance in the wide frequency band between 600 Hz and 1500 Hz. The index dropped after surgery, indicating a decrease in transmission. The postoperative measurements revealed a reverse trend in the same variable, which can be attributed to healing. Significant changes caused by the sternotomy and subsequent healing processes were observed using vibration measurement.