Extended Transsphenoidal Approach with Sigma-shape Osteotomy of the Maxilla: Technical Note.

The traditional sublabial transsphenoidal approach offers a limited operative field. This report describes a simple surgical technique to widen the sublabial transsphenoidal window to access the midline lesions from the planum sphenoidale to the lower clivus. This technique was developed on the basis of clinical experience and on data obtained by cadaveric dissection study. Following a sublabial incision and separation of the bilateral septal mucosa, a small Sigma-shape osteotomy of the maxilla, including the anterior nasal spine, was performed with a surgical saw. The width of the entrance to the nasal cavity ranged from 32 to 38 mm. Although the plexus of the anterior superior alveolar nerve was partially cut, our clinical experience revealed no significant sensory loss of the incisors after the Sigma-shape osteotomy. The nasal orests of the maxilla and palatine bone were drilled out, and the roof of the nasopharynx was then incised to expose the lower clival bone. Although extradural sellar or clival lesions were the focus of this approach, the intradural anatomical structures examined by cadaveric study were presented. The extended transsphenoidal approach with Sigma-shape osteotomy of the maxilla is a simple technique and provides widened access to the sellar and clival regions.