Structured Light Scanning of an Anatomical Model for Preoperative Planning of Cavernous Sinus Surgery: An Illustrative Case

Background The microsurgical anatomy of the cavernous sinus (CS) is of particular interest to skull base surgeons given its relationship with surrounding neurovascular structures, namely, the carotid artery, oculomotor, trochlear, abducens, and ophthalmic division of the trigeminal nerve. Exposure and anatomy of the CS have been extensively described in both cadaveric studies and clinical cases. However, no previous studies have utilized three-dimensional (3D) scanning for anatomical 360-degree visualization and preoperative planning of CS surgery. We present an illustrative case of an extradural approach to the CS in which a cadaveric dissection was visualized preoperatively using structured light scanning (SLS) for a better visuospatial understanding of this intricate anatomical area.

Methods 3D Scanning of Specimen: The middle fossa, orbit, and cavernous sinus were dissected bilaterally in a latex-injected, embalmed cadaveric human specimen. The specimen was scanned using a high-resolution 3D scanner based on blue light technology (Artec Space Spider, Artec 3D, Palo Alto, California, United States). The geometry and texture of the generated volumetric model were processed using the Artec Studio 12 software (Artec 3D). The 3D model was examined preoperatively to CS surgery along with a 3D reconstruction of preoperative images of the patient to acquire a comprehensive 360-degree understanding of the CS microanatomy and surrounding structures. Illustrative Case: A 32-year-old, immunocompromised woman presented with proptosis and CS syndrome due to an antifungal resistant mucormycosis pansinusitis infiltrating the CS. A right orbitozygomatic craniotomy and anterior clinoidectomy were completed to perform an extradural transcavernous sinus approach.

Results The infected tissue was debrided in and around the CS and the neurovascular structures were decompressed without complications. The clinical sensorial manifestations of the patient improved postoperatively, although ophthalmoparesia and amaurosis persisted.

Discussion The resultant volumetric model proved successful for preoperatively visualizing the complex microsurgical anatomy of the CS. Currently, the three primary 3D scanning techniques being employed perioperatively include laser scanning, SLS, and 3D photogrammetry. Several studies have used 3D scanning techniques to reconstruct and quantify structural surface changes preoperatively and postoperatively, especially with respect to corrective craniosynostosis surgery. One study used cadaveric surgical simulation to assess the feasibility of using SLS intraoperatively for registration and image guiding with favorable results. Additionally, several studies have found that SLS is able to accurately reconstruct scanned surfaces and that this technique could be useful perioperatively. In addition to preoperative surgical planning, 3D scanning could prove advantageous for neurosurgical and anatomical education as well as intraoperative image guiding and patient registration.

Conclusion Despite the extensive number of anatomical descriptions, there are no previous studies that have utilized 3D scanning technology of cadaveric dissections to understand the complex anatomy of the CS. Several studies have assessed the accuracy of SLS technology with favorable results. The generated volumetric model proved useful for surgical planning and holds promise for intraoperative use and anatomical education.