Accuracy analysis of CAS Stryker ADAPT® system for femoral trochanteric fracture using a fluoroscopic navigation system

Open access Accuracy analysis of computer-assisted surgery for femoral trochanteric fracture using a fluoroscopic navigation system: Stryker ADAPT® system, by Takai et al. Injury (2018).


ADAPT is a fluoroscopic computer-assisted surgery system which intraoperatively shows the distance from the tip of the screw to the surface of the femoral head, tip-to-head-surface distance (TSD), and the tip-apex distance (TAD) advocated by Baumgaertner et al. The study evaluated the accuracy of ADAPT.

Patients and Methods
A total of 55 patients operated with ADAPT between August 2016 and March 2017 were included as subjects. TSD and TAD were measured postoperatively using computed tomography (CT) and X-rays. The intraclass correlation coefficient (ICC) was checked in advance. The error was defined as the difference between postoperative and intraoperative measurement values of ADAPT. Summary statistics, root mean square errors (RMSEs), and correlations were evaluated.

ICC was 0.94 [95% CI: 0.90–0.96] in TSD and 0.99 [95% CI: 0.98–0.99] in TAD. The error was −0.35 mm (−1.83 mm to 1.12 mm) in TSD and +0.63 mm (−5.65 mm to 4.59 mm) in TAD. RMSE was 0.63 mm in TSD and 1.53 mm in TAD. Pearson’s correlation coefficient was 0.79 [95% CI: 0.66–0.87] in TSD and 0.83 [95% CI: 0.72–0.89] in TAD. There were no adverse events with ADAPT use.

ADAPT is highly accurate and useful in guiding surgeons in properly positioning the screws.

Pre-op 3D angiography & IO real-time vascular data integrated in microscope-based navigation by automatic patient registration with IO CT


Preoperative 3-Dimensional Angiography Data and Intraoperative Real-Time Vascular Data Integrated in Microscope-Based Navigation by Automatic Patient Registration Applying Intraoperative Computed Tomography, by Carl et al. World Neurosurgery (2018) in press, corrected proof.

To establish a workflow integrating preoperative 3-dimensional (3D) angiography data and intraoperative real-time vascular information in microscope-based navigation for aneurysm and arteriovenous malformation (AVM) surgery.

In 7 patients (3 with AVMs and 4 with aneurysms), preoperative 3D rotational angiography or computed tomography (CT) or magnetic resonance angiography data were navigated applying a 32-slice movable CT scanner for low-dose registration scanning. The 3D vasculature was segmented and visualized by microscope-based navigation along with navigated intraoperative real-time imaging data from indocyanin green angiography and duplex ultrasonography.

Automatic registration applying intraoperative CT resulted in high accuracy (registration error, 0.80 ± 0.79 mm). The effective radiation dose of the registration CT scans (0.28–0.42 mSv) was only approximately one-sixth of a standard diagnostic head CT scan. The 3D vessel architecture could be visualized accurately in the operating microscope heads-up display and on the navigation screens in the same projection as the view angle of the surgeon, both facilitating orientation in 3D space, providing a better understanding of anatomy. In addition, intraoperative real-time modalities could be coregistered with high precision, providing further information during the course of the vascular procedure.

Registration CT imaging facilitates integrating preoperative and intraoperative vascular image data with a low registration error and low radiation exposure for the patient, improving the understanding of 3D vascular anatomy during surgery with easier identification of feeding vessels in AVMs, and of the projection and configuration of aneurysms.

overview of the implemented workflow: in the preoperative workflow image
data depicting vascular information generated by CTA, TOF-MR, and 3-D
rotational angiography (DynaCT) are rigidly registered and visualized for
planning; the intraoperative workflow starts with the acquisition of an
intraoperative low-dose CT scan for automatic patient registration, after
measuring the registration accuracy, the preoperative planning is registered
rigidly to the registration scan, allowing intraoperative 3-D visualization,
microscope-based navigation, and integration of further intraoperative realtime
vascular data

Current role of computer navigation in total knee arthroplasty (review)


Current Role of Computer Navigation in Total Knee Arthroplasty, by Christopher W. Jones and Seth A. Jerabek, AAHKS Symposium (Accepted manuscript, in press).


Computer-assisted surgical (CAS) navigation has been developed with the aim of improving the accuracy and precision of total knee arthroplasty (TKA) component positioning and therefore overall limb alignment. The historical goal of knee arthroplasty has been to restore the mechanical alignment of the lower limb by aligning the femoral and tibial components perpendicular to the mechanical axis of the femur and tibia. Despite over four decades of TKA component development and nearly two decades of interest in CAS, the fundamental question remains; does the alignment goal and/or the method of achieving that goal affect the outcome of the TKA in terms of patient reported outcome measures and/or overall survivorship? The quest for reliable and reproducible achievement of the intra-operative alignment goal has been the primary motivator for the introduction, development and refinement of CAS navigation. Numerous proprietary systems now exist and rapid technological advancements in computer processing power are stimulating further development of robotic surgical systems. Three categories of CAS can be defined; image-based large console navigation; imageless large-console navigation and more recently, accelerometer based hand-held navigation systems have been developed.

A review of the current literature demonstrates that there are enough well-designed studies to conclude that both large-console CAS and handheld navigation systems improve the accuracy and precision of component alignment in TKA. However, missing from the evidence base, other than the subgroup analysis provided by the AOANJRR, are any conclusive demonstrations of a clinical superiority in terms of improved patient reported outcome measures and/or decreased cumulative revision rates in the long term. Few authors would argue that accuracy of alignment is a goal to ignore, therefore in the absence of clinical evidence, many of the arguments against the use of large console CAS navigation centre on the prohibitive cost of the systems. The utilization of low-cost, handheld CAS navigation systems may therefore bridge this important gap and over time, further clinical evidence may emerge