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Use of 3D visualisation of medical images for planning and intraoperative localisation of superficial brain tumours: our experience

Background. In the present article, we assessed the role, adequacy and application accuracy of intraoperative visual guidance based on the computer 3D visualisation of preoperative medical images in the surgery of superficial brain tumours. Materials and methods. For 30 consecutive patients with convexity meningioma or cortical/subcortical brain tumour, we used 3D visualisation of post-contrast fast spoiled gradient recalled (FSPGR) MR images to plan optimal positions for the trepanation opening and/or corticotomy site. At the beginning of the surgery, planned positions were transferred to the scalp and the cortical surface of the patient by visually matching the 3D surfaces with the operative field. The feasibility of visual matching was assessed by counting the number of cases in which this was possible. On the exposed cortical surface, we measured the mismatch between the centre of the actual trepanation opening and the planned corticotomy site, where possible. Results. During computer-assisted 3D planning, the centre of the trepanation opening, initially defined on the basis of 2D diagnostic images, was redefined in all our cases by an average repositioning distance of 19.7 mm ± 7.6 mm. During surgery, the transfer of the planned centre of the trepanation opening and the corticotomy site was possible in all (30/30) and in 70% (19/27) of the cases, respectively. Where assessable, the mismatch between the centre of the actual trepanation opening and the planned corticotomy site was less than 1 cm in 70% of cases (12/17) and more than 2 cm in 6% (1/17) of cases. Conclusions. Intraoperative visual guidance based on 3D visualisation proved to be adequate and accurate for locating superficial brain tumours in cases where transfer of planned surgical targets to the surgical field was possible. Decision about its use should be based on preoperative computer-assisted 3D planning, in which the feasibility of visual matching during surgery can and must be assessed.