gms | German Medical Science

Objective: Advanced multimodal neuroimaging acquisition, computing and processing are essential for safe maximal resection of deep-seated and in eloquent areas located lesions. However, do to the uncontrolled effects of brain shift, an iterative intraoperative deformation correction framework is needed. For example, the intra-operative use of 3D ultrasound has improved target registration errors, currently in the range of 3-4mm. In this study, we tested the accuracy of a stereotactically catheter guided approach relying exclusively on pre-operative multimodal imaging data. We hypothesized that minimal invasive catheter guided microsurgical approaches could minimize effects of brain shift.

Methods: In this feasibility study (03–11/2017), consecutively treated patients harbouring deep-seated (≥5cm apart from the cortical surface), highly eloquently located lesions were included. Frame-based multimodal imaging-guided stereotactic technique was used for both - trajectory planning and catheter implantation targeting the center of the lesion. A minimal trajectory vessel distance of 2mm was requested. After removal of the frame, an intraoperative CT (iCT) was performed and fused with the preoperative multimodal imaging data including diffusion-tensor-imaging for frameless navigation. During resection continuous intraoperative monitoring was used. Extent of resection was assessed by early postoperative MRI. Neurological outcome was assessed postoperatively and 6 weeks later.

Results: Five patients with a symptomatic cavernoma located in the basal ganglia (n=2), the capsula interna (n=2) and the thalamus (n=1), and 1 patient with a pilocytic astrocytoma of the thalamus were included. The implanted catheter matched the preoperative trajectory as documented by fusioned iCT data in all patients. Brainstem spatulas were used for preparation along the catheter. The diameter of the corticotomy was in the range of 3mm. Intraoperatively, neuronavigation data continued to match the course of the catheter throughout the surgical course. Complete resection was achieved in all patients. Mean duration of stereotactic surgery/microsurgery was 23min and 3.5h, respectively. Postoperatively, one patient presented a mild hemiparesis and an aphasia, which completely resolved at last follow-up. All other patients remained asymptomatic or demonstrated a neurological improvement.

Conclusion: Minimal invasive stereotactic catheter-guided microsurgery can precisely target complex located deep seated lesions and minimize effects of brain shift.