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 tissueattached 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 38, 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. ß

Evaluation of a fluoroscopy-based navigation system enabling a virtual radiation-free preview of X-ray images for placement of cannulated hip screws. A cadaver study

“…In addition, future developments should concentrate on the development of DRB fixation methods that provide a rigid but minimally invasive fixation to the bone. Still, this problem has not yet been resolved in this or any other study; invasive fixation techniques using Schanz screws are still the method of choice [25].…”

Comparison of 2D and 3D navigation techniques for percutaneous screw insertion into the scaphoid: Results of an experimental cadaver study

“…The recognized problem of minimal shifts between specimens and the splint was solved by firm placement on a special splint as demonstrated by others [4,14]. For the navigation to be precise, it is important that stable, motion-free reference markers be placed near the anatomic region of interest and registered by the navigation system [15,16]. The first important parameter to be addressed was the total operation time.…”

Leg Length and Offset Measures with a Pinless Femoral Reference Array during THA

“…Experimental attempts to use noninvasive array systems for cranial interventions consisting of a small base plate fixated by an attachment headband around the distal thigh of cadavers revealed substantial translational and rotational movements during minor manipulations of the affected lower extremity [11]. Therefore, an invasive bony fixation of the reference array with the help of pins or wires is used routinely during computer-assisted joint arthroplasty.…”

“…Recently, new imageless stem navigation algorithms have been developed to measure LL and OS changes intraoperatively [15,19]. However, bony fixation of a reference marker array in the femur during these navigation procedures theoretically involves the risk of infection at the pin implantation site and/or the risk of iatrogenic femoral stress fractures and/or may loosen in osteoporotic bone [8,11,13,16,29]. Noninvasive registration techniques with external reference markers are used predominantly in navigated procedures around the cranium [14], but also have been used in total joint arthroplasty [24].…”