Intraoperative Angle Measurement of Anatomical Structures: A Systematic Review

Abstract

Ensuring precise angle measurement during surgical correction of orientation-related deformities is crucial for optimal postoperative outcomes, yet there is a lack of an ideal commercial solution. Current measurement sensors and instrumentation have limitations that make their use context-specific, demanding a methodical evaluation of the field. A systematic review was carried out in March 2023. Studies reporting technologies and validation methods for intraoperative angular measurement of anatomical structures were analyzed. A total of 32 studies were included, 17 focused on image-based technologies (6 fluoroscopy, 4 camera-based tracking, and 7 CT-based), while 15 explored non-image-based technologies (6 manual instruments and 9 inertial sensor-based instruments). Image-based technologies offer better accuracy and 3D capabilities but pose challenges like additional equipment, increased radiation exposure, time, and cost. Non-image-based technologies are cost-effective but may be influenced by the surgeon’s perception and require careful calibration. Nevertheless, the choice of the proper technology should take into consideration the influence of the expected error in the surgery, surgery type, and radiation dose limit. This comprehensive review serves as a valuable guide for surgeons seeking precise angle measurements intraoperatively. It not only explores the performance and application of existing technologies but also aids in the future development of innovative solutions.

Measurements of Spatial Angles Using Diamond Nitrogen–Vacancy Center Optical Detection Magnetic Resonance

“…The projections of the magnetic field on the four NV axes obtained through ODMR characteristics can be used to detect the vector magnetic field [26,27]. As shown in Figure 1b, the ground-state electron energy level 3 A 2 exhibits a zero-field splitting (ZFS) of D = 2.87 GHz between the spin states with ms = 0 and ms = ±1. In the presence of an external magnetic field, the electron spin of the NV center will undergo Zeeman splitting, with the projection along the diamond NV axis linearly dependent on the magnetic field.…”

“…The application of spatial angle measurement is very extensive, involving multiple fields such as materials science, biomedicine, control systems, aerospace, and aviation, and it is of great significance for research and practical applications [ 1 , 2 , 3 , 4 ]. Angle measurement is mainly divided into two types: contact and non-contact.…”