Six-Year Single Centre Experience with Frameless, Fiducial-Less Deep Brain Stimulation in Parkinsons Disease:...

Frameless and fiducial-less deep brain stimulation (DBS) guided by intraoperative cone-beam CT has emerged as a less invasive alternative to frame-based stereotaxy, yet comprehensive long-term data remain limited. This study summarizes six years of institutional experience with O-arm-navigated, frameless, fiducial-less subthalamic nucleus (STN) DBS for Parkinson's disease.

Forty-two consecutive patients with idiopathic Parkinson's disease underwent bilateral STN-DBS using O-arm-based registration and NexFrame targeting between 2018 and 2024. Preoperative planning incorporated structural MRI and diffusion tractography-derived connectivity-based STN parcellation. Accuracy was assessed by postoperative CT-MRI fusion, and clinical outcomes were evaluated at 12 months using UPDRS III and levodopa equivalent daily dose (LEDD). Postoperative lead reconstruction and volume-of-tissue-activation modelling were performed in SureTune 3.

All 84 electrodes were successfully implanted with a mean target registration error of 0.47 ± 0.09 mm and a mean vector error of 1.19 ± 0.48 mm. No lead revisions were required. At 12 months, UPDRS III improved from 33.4 ± 7.2 to 14.6 ± 4.9 (-56.3%; p < 0.001), and LEDD decreased by 49.9% (p < 0.001). Complications were minor and included one transient peri-lead edema and one connector-related issue. In most patients, active contacts were located within the dorsolateral (motor) STN, consistent with robust clinical benefit.

In this single-centre retrospective series, O-arm-navigated frameless and fiducial-less STN-DBS was associated with favourable implantation accuracy, good motor outcomes, and a low complication rate. In the absence of a contemporaneous control cohort, these findings should be interpreted as supporting the technical feasibility and clinical utility of this workflow rather than demonstrating superiority or non-inferiority versus frame-based DBS.