Evolution and Stagnation of Image Guidance for Surgery in the Lateral Skull: A Systematic Review 1989-2020

Abstract

Objective: Despite three decades of pre-clinical and clinical research into image guidance solutions as a more accurate and less invasive alternative for instrument and anatomy localization, translation into routine clinical practice for surgery in the lateral skull has not yet happened. The aim of this review is to identify challenges that need to be solved in order to provide image guidance solutions that are safe and beneficial for use during lateral skull surgery and to synthesize factors that facilitate the development of such solutions. Methods: Literature search was conducted via PubMed using terms relating to image guidance and the lateral skull. Data extraction included the following variables: image guidance error, imaging resolution, image guidance system, tracking technology, registration method, study endpoints, clinical target application, and publication year. A subsequent search of FDA 510(k) database for identified image guidance systems and extraction of the year of approval, intended use, and indications for use was performed. The study objectives and endpoints were subdivided in three time phases and summarized. Furthermore, it was analyzed which factors correlated with the image guidance error. Factor values for which an error ≤0.5 mm (μ_error + 3σ_error) was measured in more than one study were identified and inspected for time trends. Results: A descriptive statistics-based summary of study objectives and findings separated in three time intervals is provided. The literature provides qualitative and quantitative evidence that image guidance systems must provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial application during surgery in the lateral skull. Spatial tracking accuracy and precision and medical image resolution both correlate with the image guidance accuracy, and all of them improved over the years. Tracking technology with accuracy ≤0.05 mm, computed tomography imaging with slice thickness ≤0.2 mm, and registration based on bone-anchored titanium fiducials are components that provide a sufficient setting for the development of sufficiently accurate image guidance. Conclusion: Image guidance systems must reliably provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial use during surgery in the lateral skull. Advances in tracking and imaging technology contribute to the improvement of accuracy, eventually enabling the development and wide-scale adoption of image guidance solutions that can be used safely and beneficially during lateral skull surgery.

Keywords: accuracy; image-guidance; lateral skull; lateral skull base; neurotology; surgical navigation; temporal bone; temporal evolution.

Figure 1

Search strategy and PRISMA data collection flow diagram.

Figure 2

Market approval year of commercial image guidance systems (left) and clinical studies (middle, right) included in the present literature review in chronological order.

Figure 3

Proportion of the number of use cases for freehand image guidance per anatomical region. The use cases were extracted from the indications for use of commercial freehand image guidance systems used in the studies included in this literature review and were categorized into anatomical regions. SB, skull base; ASB, anterior skull base; LSB, latera skull base.

Figure 4

Evolution of the image guidance error in clinical (top) and preclinical cadaver (bottom) applications. The gray area depicts an error range ≤0.5 mm, and the gray lines depict the error trendlines. NA, value not available/reported.

Figure 5

Reported image guidance errors for different (A) tracking modalities (none refers to stereotactic frames), (B) optical tracking cameras, (C) slice thickness values, and (D) registration methods.

Figure 6

Evolution of CT image slice thickness used in image guidance applications. The gray line depicts the image resolution trendline.