Comparison study of intraoperative surface acquisition methods for surgical navigation.

Area of Science:

• Medical Imaging
• Surgical Navigation
• Biomedical Engineering

Background:

• Soft-tissue image-guided interventions necessitate accurate surface digitization for intraoperative correspondence.
• Current methods for surface acquisition can introduce registration errors, impacting surgical precision.

Purpose of the Study:

• To investigate the effect of inexpensive surface acquisition techniques on target registration error and surface registration error (SRE) for soft tissue.
• To compare the accuracy of three organ spatial digitization methods: tracked laser-range scanner (LRS), tracked pointer, and tracked conoscopic holography sensor (conoprobe).

Main Methods:

• Acquired surfaces of phantoms and biological tissues using LRS, tracked pointer, and conoprobe.
• Registered acquired surfaces to CT image volume counterparts.
• Systematically compared image-to-physical registration accuracy across the three digitization methods.

Main Results:

• The conoprobe demonstrated statistically smaller registration errors compared to the tracked pointer and LRS (p<0.01).
• Conoprobe achieved lower SRE values (e.g., 1.73 ± 0.77 mm on porcine liver) than LRS (3.25 ± 0.78 mm) and tracked pointer (4.44 ± 1.19 mm).
• Results indicate that tissue displacement from contact forces compromises registration accuracy with tracked surgical instruments.

Conclusions:

• Tracked conoscopic holography (conoprobe) provides a more accurate alternative for digitizing soft tissue surfaces in clinical settings.
• This non-contact method minimizes errors associated with tissue manipulation, improving registration accuracy.
• The conoprobe outperforms LRS and tracked pointers for soft-tissue surface digitization in image-guided interventions.