title: Intraoperative forces and moments analysis on patient head clamp during awake brain surgery.
abstract: In brain surgery procedures, such as deep brain stimulation, drug-resistant epilepsy and tumour surgery, the patient is intentionally awakened to map functional neural bases via electrophysiological assessment. This assessment can involve patient's body movements; thus, increasing the mechanical load on the head-restraint systems used for keeping the skull still during the surgery. The loads exchanged between the head and the restraining device can potentially result into skin and bone damage. The aim of this work is to assess such loads for laying down the requirements of a surgical robotics system for dynamic head movements compensation by fast moving arms and by an active restraint able to damp such actions. A Mayfield(®) head clamp was tracked and instrumented with strain gages (SGs). SG locations were chosen according to finite element analyses. During an actual brain surgery, displacements and strains were measured and clustered according to events that generated them. Loads were inferred from strain data. The greatest force components were exerted vertically (median 5.5 N, maximum 151.87 N) with frequencies up to 1.5 Hz. Maximum measured displacement and velocity were 9 mm and 60 mm/s, with frequencies up to 2.8 Hz. The analysis of loads and displacements allowed to identify the surgery steps causing maximal loads on the head-restraint device.
authors.affiliation: Bioengineering Department, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133, Milan, Italy. danilo.delorenzo@mail.polimi.it
authors.forename: Danilo
authors.initials: D
authors.lastname: De Lorenzo
authors.forename: Elena
authors.initials: E
authors.lastname: De Momi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Conti
authors.forename: Emiliano
authors.initials: E
authors.lastname: Votta
authors.forename: Marco
authors.initials: M
authors.lastname: Riva
authors.forename: Enrica
authors.initials: E
authors.lastname: Fava
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bello
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Ferrigno
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D001921:Brain / Q000601:surgery*; D006257:Head / Q000502:physiology* / Q000601:surgery*; D006801:Humans; D009068:Movement; D019635:Neurosurgical Procedures / Q000295:instrumentation* / Q000379:methods*; D011187:Posture; D012149:Restraint, Physical / Q000295:instrumentation / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D013525:Surgical Instruments; D014851:Wakefulness