title: Experimental validation of noninvasive referencing in navigated procedures on long bones.
abstract: Navigation procedures in orthopedic surgery require fixation of reference markers to the anatomic region of interest. Inadequate fixation might lead to micromotion or loosening of the reference marker, consequently causing registration failures or errors in navigation. Osseous rigid fixation is usually achieved by minimally invasive Schanz screws or pins. The goal of this study was to evaluate a non invasive external fixation device, a headband so far used in cranial navigation, as an alternative invasive fixation technique to reference markers in the femur. A common navigation system with an adapted trauma software application was used to track the positions of the soft tissue-attached headband relative to an invasive reference marker on the femur during manipulations of the thigh. Relative translative and rotational movements of the headband were measured during defined movements of the hip and knee and manipulations of the headband itself. The results revealed high translative and rotational movements, up to 6 mm and 3 degrees , respectively, due to minor manipulations of the affected lower extremity. Noninvasive soft tissue fixation with a headband does not allow rigid fixation for accurate navigated registration or operative procedures at the femur. Necessary intraoperative movements or manipulations would cause substantial registration failures. Invasive fixation techniques with screws or pins are still the method of choice.
authors.affiliation: Trauma Department, Hannover Medical School, Carl Neubergstr. 1, 30625 Hanover, Germany. kendoff.daniel@mh-hannover.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Kendoff
authors.forename: Aleksander
authors.initials: A
authors.lastname: Bogojević
authors.forename: Musa
authors.initials: M
authors.lastname: Citak
authors.forename: Mustafa
authors.initials: M
authors.lastname: Citak
authors.forename: Christian
authors.initials: C
authors.lastname: Maier
authors.forename: Georg
authors.initials: G
authors.lastname: Maier
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
authors.forename: Tobias
authors.initials: T
authors.lastname: Hüfner
mesh_terms: D001863:Bone Screws; D002102:Cadaver; D005264:Femoral Fractures / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D005269:Femur / Q000033:anatomy & histology* / Q000601:surgery*; D006621:Hip Joint / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology; D009984:Orthopedic Fixation Devices; D019637:Orthopedic Procedures / Q000379:methods*; D016059:Range of Motion, Articular; D012016:Reference Values; D012984:Software; D013314:Stress, Mechanical; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*