Using an instrumented hammer to detect the rupture of the pterygoid bone plate: an animal study

Abstract

Craniofacial osteotomies involving pterygomaxillary disjunction are common procedures in maxillofacial surgery to detach the pterygoid plates from the palatal bones. Surgeons still rely on their proprioception to determine when to stop impacting the osteotome, which is important to avoid complications such as dental damage and bleeding. Our group has developed a technique consisting in using an instrumented hammer that can provide information on the mechanical properties of the tissue located around the osteotome tip. The aim of this study is to determine whether a mallet instrumented with a force sensor can be used to predict the crossing of the osteotome through the pterygomaxillary plate. 31 osteotomies were carried out in 16 lamb skulls. For each impact, the force signal obtained was analyzed using a dedicated signal processing technique. A prediction algorithm based on an SVM classifier was applied to the database. We showed that the device can detect the crossing of the osteotome, sometimes before its occurrence. The prediction accuracy of the device was 94.7%. The method seemed to be sensitive to the thickness of the plate and to crack apparition and propagation. These results pave the way for the development of a per-operative decision support system in maxillofacial surgery.