Application of Anatomical Landmarks: Enhancing Vascular Approaches to the Sphenopalatine Artery

Abstract

The nasoseptal flap is a well‐recognized “work‐horse” flap for anterior skull base reconstruction. The sphenopalatine artery (SPA), which accounts for a large portion of the arterial supply in the nasal cavity, forms a basis for the flap pedicle. In addition, the identification of the SPA as it emerges from the pterygopalatine fossa into the nasal cavity via the sphenopalatine foramen (SPF) is useful during the transpterygoidal approach to the infratemporal fossa. This identification is also useful for treatment of epistaxis in the nasal cavity, and aids in the prevention of vascular complications in a surgical setting. Previous studies have shown the relationship of the sphenopalatine foramen to the floor of the nasal cavity, choanal arch, and maxillary line. To enhance endoscopic visualization this study set out to identify the relationship of the anteroinferior bony border of the sphenoid sinus, the superior nasal concha, and the middle nasal concha as anatomical landmarks to the SPF.A total of n = 33 cadaveric hemisections were studied. In addition, the SPF was identified in coronal computerized tomography (CT) scans of the dissected cadavers acquired from the Anatomical Bequest Program at the Mayo Clinic (IRB approval #19‐010471), n = 8. Nasal mucosa was reflected from the lateral nasal wall where the SPF was located. The exit of the SPA’s main arterial trunk at the SPF was measured in relation to the sphenoid sinus, superior nasal concha, and middle nasal concha and the number of branches was recorded. Measurements on CT imaging were taken posterior to the ostiomeatal unit and maxillary sinus at initial visualization of the sphenoid sinus. Measurements of the SPF in relation to the inferior bony boundary of the sphenoid sinus were recorded (mm). All radiologic images were collected, and measurements were taken using Association for Quality Imaging (AQI) software. Images were analyzed and processed using Fiji ImageJ software.Results of this study showed the immediate surgical relationship of the sphenoid sinus, superior nasal concha, and middle nasal concha to the SPA as it traverses the SPF into the nasal cavity. Average distance from the SPF to the anterior‐inferior bony boundary of the sphenoid sinus was 2.5mm, the superior nasal concha was 4.12mm, and the middle nasal concha was 2.86mm. Radiological measurements taken in coronal CT images from the inferior bony boundary of the SPF to the inferior bony boundary of the sphenoid sinus was on average 4.94mm. Number of primary branches off of the SPA arterial trunk, and branching patterns varied between 2–3 with instances of a single long SPA arterial trunk traveling more than 3 mm followed by two small branches inferiorly. These relationships can be used to safely identify the SPA as it exits the SPF during surgery to prevent vascular complications due to occluded visualization of the region.Support or Funding InformationAmerican Association of Anatomists Short‐Term Visiting Scholarship Award