Respiratory motion control for stereotactic and robotic liver interventions.

BACKGROUND

Control of respiratory motion is an essential prerequisite for stereotactic computer-assisted and robotic interventions in the liver.

METHODS

The respiratory motion control error (RMCE) of temporary disconnections of the endotracheal tube (ETT) in anaesthetized patients has been evaluated during computer tomography (CT)-guided liver punctures. Two arterial and portal phase contrast-enhanced planning CTs were obtained during one ETT disconnection. After liver puncture, a native control CT was performed during a second ETT disconnection. By image fusion, the Euclidean errors of corresponding external and internal targets were calculated as baseline measures. RMCE was obtained by subtracting the Euclidean error during one ETT disconnection from the Euclidean error during two ETT disconnections.

RESULTS

In 26 patients, the overall mean RMCE showed 1.98 +/- 0.93 (range 0.44-4.02) mm for external targets and 1.41 +/- 0.75 (range 0.46-3.18) mm for the internal targets, without significant difference in means (p = 0.558). No complications were noted.

CONCLUSIONS

Temporary ETT disconnections are safe and may control respiratory motion for liver interventions within 4 mm.