Dependable Automated Approach for Measuring the Retrograde Superior Ramus Screw Corridor in Pelvic Fracture Fixation

Area of Science:

• Orthopedic surgery
• Medical imaging analysis
• Surgical planning

Background:

• Accurate percutaneous placement of retrograde superior ramus screws (SRS) requires precise measurement of the intraosseous corridor.
• Conventional manual measurement methods for this corridor are subjective and lead to observer variability.
• A need exists for an automated and dependable method to determine the retrograde SRS corridor.

Purpose of the Study:

• To develop an automated, computed tomography (CT) image-based algorithm for identifying the retrograde SRS corridor with maximum diameter.
• To compare the reliability and accuracy of the automated method against conventional manual measurements.
• To assess screw applicability and influencing factors (sex, age, height, weight) on corridor dimensions.

Main Methods:

• An automated CT image-based search algorithm was developed to find the maximum diameter retrograde SRS corridor.
• The automated method was compared to a manual method in 17 pelves for reliability assessment.
• Both methods measured corridor diameter, length, and orientation in 204 pelves (Chinese population), assessing intra- and interobserver agreement using RMSE and Bland-Altman plots.

Main Results:

• The automated method demonstrated superior intra- and interobserver reliability (ICC: 0.998, 0.995) compared to the manual method (ICC: 0.925, 0.918) for corridor diameter.
• The automated method identified a significantly larger corridor diameter (mean difference: 0.9 mm, RMSE: 1.1 mm) than the manual method.
• Females exhibited a smaller corridor diameter (7.5 mm) than males (10.4 mm), with female sex being the most significant factor (β = -0.583); automated method improved screw applicability for females.

Conclusions:

• The automated method offers enhanced reliability and identifies a larger retrograde SRS corridor for screw placement compared to manual methods.
• Significant sex-based differences in corridor diameter were observed, with females having smaller corridors.
• Current automated approach requires further development into integrated, user-friendly software for clinical traumatologist application.