Craniosynostosis is a disorder in which the cranial sutures of an infant’s skull are prematurely fused. As a result, brain growth is restricted causing dysmorphism and functional sequelae. Treatment involves surgically removing the fused suture or remodeling the skull by osteotomies and can be performed either open or endoscopically. The endoscopic approach is minimally invasive. However, the extent of the osteotomies is limited using conventional surgical instruments due to the unique curvature of the skull. There is therefore a need to develop a novel steerable bone cutting tool that can perform more extensive osteotomies along the skull surface using minimal access incisions.

A novel steerable instrument was developed and prototyped, which allows performance of an extended range of osteotomies on the skull using key-hole incisions. The tool comprises a cable driven articulating bending section and end-effector with a cable driven bone punch that is manually operated using a driving handle. The end-effector also incorporates a dural protector, scalp retractor and flexible endoscope for visualization. The workspace of the tool was determined to have a deflection at the tool tip of 23.7 mm and 120° of yaw. A phantom craniosynostosis model was developed and used as a test bed. The tool was inserted through a single vertex incision and demonstrated reachability of the tool tip to distal areas of the skull along the frontal, parietal and occipital bones. The tool demonstrated the ability to successfully cut simulated bone. This tool represents a first stage in the development of a minimally invasive robotic cranial bone cutting instrument and is a paradigm shift in the treatment of patients with craniosynostosis.