Mapping surgical coordinates of the sphenopalatine foramen: surgical navigation study

Abstract

AbstractObjectives:To identify measurements that may help intra-operative localisation of the sphenopalatine foramen.Design:The study used three-dimensional surgical navigation software to study radiological anatomy, in order to define the distances and angulations between identifiable bony landmarks and the sphenopalatine foramen.Results:The distance from the anterior nasal spine to the sphenopalatine foramen was 59 mm (±4 mm; inter-observer variation = 0.866; intra-observer variation = 0.822). The distance from the piriform aperture to the sphenopalatine foramen was 48 mm (±4 mm; inter-observer variation = 0.828; intra-observer variation = 0.779). The angle of elevation from the nasal floor to the sphenopalatine foramen was 22° (±3°; inter-observer variation = 0.441; intra-observer variation = 0.499).Conclusions:The sphenopalatine foramen is consistently identifiable on three-dimensional, reconstructed computed tomography scans. Repeatable measurements were obtained. The centre point of the foramen lies 59 mm from the anterior nasal spine at 22° elevation above the plane of the hard palate and 48 mm from the piriform aperture. We discuss how these data could be used to facilitate intra-operative location of the sphenopalatine foramen in difficult cases.