Reconstruction of the Anterior Wall of the Sphenoid Sinus with a Composite Osteomucosal Middle Turbinate Pedicled Flap

Objectives: To study the anatomical foundations of the endoscopic endonasal reconstruction of the anterior wall of the sphenoid sinus with a pedicled osteomucosal middle turbinate flap and to present an illustrative surgical case.

Study Design: Anatomical dissection and illustrative case.

Methods: Three anatomical dissections were performed to investigate the feasibility of a composite osteomucosal middle turbinate pedicled flap to reconstruct the anterior wall of the sphenoid sinus. First, near total septectomy was performed to simulate cases where the standard septal flap is not available. A wide sphenoidotomy was carried from the skull base to the sphenoid sinus floor and from orbit-to-orbit. The mucosa from the anterior edge of the vertical portion of the right middle turbinate was removed to simulate the surgery. This step is important to improve the healing and attachment of the flap to the contralateral orbit. The vertical and diagonal portions of the middle turbinate were transected with sharp scissors. Careful dissection of the anterior portion of the horizontal attachment of the middle turbinate was performed to allow adequate mobilization of the turbinate while maintaining its blood supply. Once the dissection was completed, the middle turbinate was rotated to cover and replace the anterior wall of the sphenoid sinus. The meatal surface was positioned facing the nasal cavity.

Illustrative Case: A fifty one year old female presented two years after undergoing endoscopic endonasal resection of a craniopharyngioma with resultant thin reconstruction of the cranial base at the sella, tubercullum and planum sphenoidale. She was recently diagnosed with obstructive sleep apnea necessitating the use of CPAP. There was concern for risk of CSF leak and pneumocephalus with use of CPAP in the setting of a fragile postoperative cranial base reconstruction. Endoscopic exam revealed wide bilateral sphenoidotomy and near total septectomy. In the absence of the standard septal flap, the reconstruction of the anterior sphenoid sinus wall was performed utilizing a right composite osteomucosal middle turbinate pedicled flap. The flap covered the entire defect of the anterior wall of the sphenoid sinus. Three weeks after surgery, the flap healed very well and formed reliable reconstruction of the anterior sphenoid wall. CPAP was started without complication after 6 months.

Results: In all dissections, the middle turbinate flap demonstrated adequate arch of rotation to cover the anterior wall of the sphenoid sinus. The length of the turbinate was sufficient to cover the orbit-to-orbit defect. The anterior turbinate edge rested adequately against the contralateral orbit wall in all dissections. However, the cranial-caudal width of the flap was not enough to cover completely the maximum cranial-caudal defect from the skull base to the sphenoid sinus floor.

Conclusion: The composite osteomucosal middle turbinate pedicled flap is a useful tool to reconstruct the anterior wall of the sphenoid sinus. In cases of complete ethmoidectomy up to the skull base and extensive drilling of the sphenoid sinus floor, the unilateral middle turbinate flap is not sufficient to completely cover the cranial-caudal dimension of the defect. Other options should be considered, such as bilateral flaps.