Stereotactic Radiofrequency Thermocoagulation of Hypothalamic Hamartoma Using Robotic Guidance (ROSA) Coregistered with O-arm Guidance-Preliminary Technical Note.

INTRODUCTION: Treatment options for hypothalamic hamartoma (HH) include microvascular surgery, stereotactic radiofrequency thermocoagulation (SRT), laser interstitial thermal therapy, or Gamma Knife surgery. During SRT, thermographic monitoring cannot be performed and therefore highly accurate placement of electrode and confirmation of its position are required. We have used robotic guidance (ROSA) and coregistered it with O-arm for performing ablation of hamartoma.

METHODS: Five patients with HH and gelastic seizures underwent SRT. Robotic guidance (ROSA) was used for placement of electrodes. An O-arm was used for coregistering and confirming the robotic trajectory with real-time intraoperative imaging. Intraoperative computed tomography was merged with preoperative magnetic resonance imaging to confirm the exact position and trajectory of the electrode. Ablation was performed using a radiofrequency generator (70°C for 60 seconds). Multiple target sites were ablated to achieve proper ablation and disconnection.

RESULTS: Most patients (4/5) had International League Against Epilepsy class I outcome. One patient 2 sittings of lesioning. All but 1 electrode could be placed in the planned trajectories. One electrode was detected to have a medial deviation, and it had to be revised. No permanent complication was observed.

CONCLUSIONS: SRT is a cost-effective method of treating HH when compared with laser interstitial thermal therapy. With the use of a robotic arm we have demonstrated accurate placement of electrodes. Intraoperative computed tomography acquired using an O-arm can be merged with preoperative magnetic resonance imaging. This confirms electrode location and trajectory on a real-time basis by performing intraoperative imaging. This method is safe and can be used for radiofrequency ablation of HH.