Localization of sentinel lymph nodes using augmented-reality system: a cadaveric feasibility study.

PURPOSE: Sentinel lymph node biopsy (SLNB) helps stage melanoma. Pre-surgical single-photon emission computed tomography/computed tomography (SPECT/CT) visualizes draining lymph nodes, but intraoperative gamma probe detection only estimates SLN location. This study evaluates augmented reality (AR) for projecting pre-surgical SLN imaging onto patients to aid precise localization and extraction.

METHODS

Molecular sieves (8 mm) incubated in fluorine-18 simulated lymph nodes and were implanted in the head and neck region of cadavers. Positron emission tomography/magnetic resonance imaging (PET/MRI) replaced SPECT/CT due to institutional restriction on cadavers. Virtual PET/MRI renderings were projected using the HoloLens 2 and custom software. Five cadavers underwent surgeries with standard, AR, and AR with head movement compensation methods.

RESULTS

AR achieved a mean surface localization error of 2.5±2.0 mm (range, 0-8 mm) and a depth error of 2.3±1.7 mm (range, 1-7 mm), both within PET voxel resolution. For more challenging level V nodes, the mean surface error slightly increased to 2.9 mm. Compared to manual surface marking, which had an average error of 18.6±13.0 mm (range, 6-62 mm), the AR system significantly reduced errors both in the head-straight and rotated positions (p <.001). Additionally, the AR system reduced the task completion time by 74% (35.1/47.4 s), with an average time of 12.3 s compared to 47.4 s for manual methods.

CONCLUSION

The AR system demonstrated high accuracy and efficiency in SLN localization, integrating head-movement compensation and 3D visualization to improve precision and reduce operating room time.

CLINICAL TRIAL NUMBER: Not applicable.