The combination of semi-sitting position and intraoperative MRI--first report on feasibility

Intraoperative MRI (iMRI) has been established as a routine imaging modality with a remarkable impact on specific neurosurgical procedures. The technological advancement continuously extends the spectrum of iMRI, leading to an increasing number of installations. Yet, procedures in which a semi-sitting position would be advantageous were beyond the reach of iMRI.

We performed an iMRI-guided surgical procedure in a patient with a cystic lesion of the inferior parieto-occipital lobe while the patient was placed in a semi-sitting position, employing a mobile 0.15-T intraoperative MRI system. For that purpose, we adapted a standard OR table according to the needs of iMRI.

Patient positioning could be accomplished easily. For intraoperative scanning, the OR table was tilted backwards so as to position the patient's head in the magnet's aperture. Obtained images were used for neuronavigated cyst evacuation via burr hole trephination after repositioning the OR table. Subsequent intraoperative imaging documented collapse of the cyst at the end of the procedure. There were no adverse effects resulting from the combination of semi-sitting position and iMRI guidance.

This report demonstrates for the first time that the combination of iMRI and the semi-sitting position is feasible and that this procedure bears specific benefits. Issues such as brain shift due to table tilting warrant further investigations in order to expand this technique to posterior fossa craniotomies.