The Cirq® Surgical System serves as an automated robotic alignment tool for cranial procedures with cranial navigation. Unlike traditional surface matching, integrating patient-to-image registration through intraoperative cone-beam CT might enhance accuracy. In this study, we delineate our experience with the Cirq-robotic arm for stereotactic biopsies and stereotactic electroencephalography (sEEG) using the Artis Pheno robotic cone-beam CT as a registration tool.

This retrospective analysis included 11 patients undergoing stereotactic biopsy (n=9) or sEEG (n=2) with the Cirq® system from January 2023 to January 2024. For patient-to-image registration, the Cirq® was mounted, and an external registration Matrix was positioned near the patient's head prior to conducting cone-beam CT with the robotic Artis Pheno. Following registration, the CT dataset was fused with the preoperative MRI, and used as the navigation data set. Demographic and clinical data were evaluated.

In 11 Cirq-robotic arm assisted surgeries, 8 cases were combined with robotic cone-beam CT for image registration. Among these, 6 patients had biopsies with median 7 (6.7-7) specimens, and 2 underwent sEEG with 12 depth electrodes. The median age was 54 (IQR 32-80), with an equal male-to-female ratio. Median lesion size was 25 (8-41) cm³ on contrast enhanced T1 and 45 (15-59) cm³ on T2 weighted imaging. Histological results were obtained for all biopsy cases. Fluorescein, confirming accurate biopsy location, was used in 4 cases and showed positivity in 75% of biopsy specimens (21/28). Median operating room times were 147 (123-151) minutes for biopsies, and 360 (339-380) minutes for sEEG procedures. Incision-to-closure times were 30 (27-37) and 236 (225-301) minutes, respectively. No complications were reported. The median dosage area product was 866 (835-966) µGym² during biopsies and 2669 (2259-3079) µGym² during electrode implantation, including two scans per sEEG procedure.

In this study, we demonstrate the feasibility and safety of intracranial interventions using the Cirq-robotic arm for stereotatic biopsies and sEEG, especially for procedures in the prone position, as surface matching can often be technically challenging in this setting. The Artis Pheno enables autonomous, surgeon-controlled intraoperative cone-beam CT scans with acceptable radiation exposure, while maintaining short incision-to-closure times. Future studies will be required to elucidate the accuracy of this technique.