2025 Proffered Presentations
S187: PIONEERING INSIGHTS INTO MICROSURGICAL CLIPPING OF POSTERIOR COMMUNICATING ARTERY ANEURYSMS THROUGH ANTERIOR CLINOIDECTOMY: 3D VOLUMETRY AND GALLIUM CASTING TECHNIQUE, A NEW PERSPECTIVE
Diego S Morales Roccuzzo1; Lena Marie Houlihan, MD, PHD2; Shadi Bsat1; Mohammadmahdi Sabahi1; David Naughton2; Ryan Gordon1; Hamid Borghei-Razavi1; Badih Adada1; 1Cleveland Clinic Florida; 2Beaumont Hospital, Dublin, Ireland
Objective: Microsurgical clipping of posterior communicating aneurysms presents varying degrees of complexity, with some cases requiring anterior clinoidectomy for better maneuverability and successful clipping. This study aims to delineate the benefits of anterior clinoidectomy in microsurgical clipping of posterior communicating aneurysms through advanced 3D volumetric analysis and the application of an innovative gallium casting technique.
Methods: Five formalin-fixed, color latex–injected cadaveric specimens preserved in 70% ethanol solution were subjected to a pterional approach. Dissection and clinoidectomy were performed under a surgical microscope, with the aid of neuronavigation. Computed acquisition of the volume of surgical freedom produced an accurate 3D model, comparing pre- and post-clinoidectomy volumes. We considered the surgical space as a two-based irregular truncated cone: Neuro-navigation through 17 points was conducted: 1 point for the surgical target structure (the center of our 3-dimensional figure, in this case, a point 4 mm posterior to the tip of the ACP); 8 points for the inner (medial) base surrounding the surgical target structure; and 8 points correlated to the outer (lateral) base. It was further explored using melted gallium to create a cast of the surgical space, which was then frozen. The metal chosen is proposed as an innovative technique in laboratory investigation due to its low melting point (≈ 30°C), non-toxic and non-radioactive nature, and commercial availability.
Results: Neuronavigation delivered 8 sets of 17 "XYZ" coordinates (pre- and post-clinoidectomy, left/right) and 6 sets of 17 "XYZ" coordinates (post-clinoidectomy, left/right). Software processing rendered two 3D shapes resembling what the surgical corridor would look like for each scenario (mean pre-clinoidectomy: 48,053.25 mm³; mean post-clinoidectomy: 54,239.75 mm³). Results do not challenge the efficacy of our model, as all tests (t-test; Mann-Whitney U test) indicated an increase in mean volume after resection of the clinoid process. Gallium casting further validated the efficacy of the 3D model, offering precise visualization of the surgical field, shaped as an irregular two-based cone.
Conclusion: The 3D virtual models demonstrated that anterior clinoidectomy significantly enhances both the working space (an irregular truncated cone) and the forthcoming gained maneuverability in microsurgical clipping of posterior communicating aneurysms when properly indicated. These findings lay the groundwork for a new method to be widely incorporated into neurosurgical training and planning, not only in the realm of vascular surgery but also in all skull-base pathology, paving the way for future research.
Keywords: Anterior clinoid process; Posterior communicating artery; Aneurysm; Clinoidectomy; Skull-base
FIG 1 – Surgical corridor of pre-Clinoidectomy scenario. Overlay of the model (Red) with correlating dissection.
FIG 2 – Surgical corridor of post-Clinoidectomy scenario. Overlay of the model (Aquamarine) with correlating dissection.
FIG 3 – Stepwise dissection and navigation showcasing the additional angle of attack gained when performing clinoidectomy. Illustration of two vectors obtained for each procedural scenario: pre-Clinoidectomy in red, and post-Clinoidectomy in aquamarine
FIG 4 - Gallium cast of the surgical space following clinoidectomy. Liquid state gallium spreads across the extensive Sylvian fissure, hence its increased outer diameter. Interactive virtual model acquired through photogrammetry of the cast: https://skfb.ly/oUrDr.
