Intraoperative 3D fluoroscopy accurately predicts final electrode position in deep brain stimulation surgery

In the absence of an intraoperative CT or MRI setup, post-implantation confirmation of electrode position in deep brain stimulation (DBS) requires patient transportation to the radiology unit, prolonging surgery time. This project aims to validate intraoperative 3D fluoroscopy (3DF), a widely available tool in Neurosurgical units, as a method to determine final electrode position.

We performed a retrospective study including 64 patients (124 electrodes) who underwent DBS at our institution. Intraoperative 3DF after electrode implantation and postoperative volumetric CT were acquired. The Euclidean coordinates of the electrode tip displayed in both imaging modalities were determined and inter-method deviations were assessed. Pneumocephalus was quantified and its potential impact in determining the electrode position analyzed. Finally, 3DF and CT-imposed exposure to radiation was compared.

The difference between the electrode tip estimated by 3DF and CT was 0.85 ± 0.03 mm, and not significantly different (p = 0.11 for the distance to MCP assessed by both methods), but was, instead, highly correlated (p = 0.91; p < 0.0001). Even though pneumocephalus was larger in 3DF (6.89 ± 1.76 vs 5.18 ± 1.37 mm³ in the CT group, p < 0.001), it was not correlated with the difference in electrode position measured by both techniques (p = 0.17; p = 0.06). Radiation exposure from 3DF is significantly lower than CT (0.36 ± 0.03 vs 2.08 ± 0.05 mSv; p < 0.0001).

Intraoperative 3DF is comparable to CT in determining the final DBS electrode position. Being a method with fewer radiation exposure, less expensive, faster and that avoids patient transportation outside the operation room, it is a valid tool to replace postoperative CT.