Evaluation of Accuracy and Reliability of a Smartphone Stereotactic Coordinates Checking Application

Surgical assistance applications for smartphones have the potential to be used in daily practice; however, regular reviews of these tools are required. StereoCheck (Mevis, São Paulo, São Paulo, Brazil) is a mobile application (app) designed to compute stereotactic coordinates as a checking tool. The present study evaluated the accuracy and reliability of the StereoCheck app.

The present observational and prospective study included 26 patients who had undergone frame-based stereotactic brain biopsy. A standard stereotactic planning software (Framelink, version 5.0 [Medtronic, Minneapolis, Minnesota, USA]) was used to define the target coordinates. The surgical planning images were transferred to StereoCheck using 2 image input methods: photographs of the screen monitor and digitally exported images of the screen monitor. Five examiners performed the target coordinate definitions using StereoCheck on 2 occasions. The accuracy and reliability of the app were evaluated in tests that compared the planning methods (app vs. standard software), multiple examiners, and sequential tests.

The StereoCheck accuracy using photographs of the screen was 2.71 ± 0.86 mm (95% confidence interval, 2.37-3.06). Using the digitally exported images, it was 0.82 ± 0.61 mm (95% confidence interval, 0.58-1.07). The accuracy between the 2 methods was greater using the exported images (P < 0.01) and was not affected by the clinical and radiological features. The accuracy of StereoCheck among multiple examiners and in sequential tests showed a mean distance between the targets and coordinates of <1.00 mm. Thus, an excellent level of reliability for the StereoCheck coordinates (intraclass correlation coefficient ≥0.8) was verified in all contexts.

StereoCheck showed satisfactory accuracy and reliability. The use of photographs to compute the coordinates could lead to a significant decrease in the accuracy of the app.