INTRODUCTION: The successful separation and reconstruction of craniopagus twins is a technically demanding procedure that necessitates comprehensive and precise pre-operative planning. The three key challenges include (1) separating complex vascular anatomy without precipitating hemodynamic collapse (2) dividing shared brain matter without compromising critical tissue, and (3) reconstructing the dura, bony skull and soft tissue scalp using limited autologous materials. Virtual surgical planning (VSP) combines 3D-modeling and simulation software for the purpose of precisely planning such complex surgeries. Customized guides and jigs can be designed during the digital planning sessions based on high-fidelity anatomical models. These tools can then be 3D-printed, sterilized, and applied to the patient in the operating room to facilitate the precise translation of virtual plans into reality. Our goal was to utilize this technology in the separation and reconstruction of craniopagus twins.
METHODS: The twins underwent initial CT and MRI angiography and venography prior to any surgery to evaluate their arterial and venous anatomy as well as the brains. 3D photographs (Canfield Vectra H1) of the twins were also taken. Repeat imaging was performed subsequent to each of the first three stages of surgery.
Based on these data, our team used VSP and 3D-printing to design and 3D print (1) osteotomy guides that minimized surgical risk by avoiding underlying vasculature and which generated portions of cortical bone that could be optimally repurposed for skull reconstruction and (2) age and size-matched normative skull-caps to serve as a template for the shape of the reconstructed skull. VSP was also used to plan incisions, skin flaps, and tissue expansion. In addition, 3D printing was used to produce intraoperative reference models highlighting the neurovasculature and brain tissue.
RESULTS AND CONCLUSION: The challenge of craniopagus separation is due to the complexity of the venous plexus and shared dural venous sinus. Therefore, separation of the venous system of the twins requires meticulous planning and stereoscopic appreciation of the vasculature. Both VSP and 3D printed models were critical as references of the venous anatomy during separation and to the survival of both twins. VSP and 3D printing were also employed successfully in predicting the scalp and skull defects and designing custom guides and jigs which were used intraoperatively and facilitated surgical reconstruction.