The safe gate to the posterior paranasal sinuses: reassessing the role of the superior turbinate

Surgery of the posterior ethmoid and sphenoid sinuses can be challenging. In 1999, a technique was described for identification of the superior turbinate and utilizing it as a landmark in endoscopic posterior ethmoidectomy and sphenoidotomy. Although this was more than a decade ago, it has not been supported by further studies. In our practice, we have routinely adopted this technique, and have modified it to allow further orientation during endoscopic surgery of the posterior sinuses. To describe a review of our technique, and to prospectively assess the value of the superior turbinate as a useful landmark during endoscopic posterior ethmoidectomy and sphenoidotomy. Fifty patients listed for endoscopic posterior ethmoidectomy with or without sphenoidotomy were included in a prospective study utilising our surgical technique. Data were collated for the success or failure of identification of the landmarks, and for any complications during the surgery. A total of 93 sides of endoscopic posterior ethmoidectomy and 73 sides of endoscopic sphenoidotomy were performed. The superior turbinate was identified in 100% of the cases. The coronal part of the superior turbinate basal lamella was identified in 60.22% of the cases, and the axial part in 88.17% of the cases. The natural sphenoid ostium was identified medial to the posterior part of the superior turbinate in 98.63% of the cases. The axial part of the superior turbinate basal lamella was a constant landmark for the level of the sphenoid ostium. The number of transverse septae between the axial part of the superior turbinate basal lamella and the skull base was studied, and was found never to exceed one septum. No major complications were recorded. One case of small posterior septal perforation was detected with no post-operative effects. Our study represents the first report of identifying the two parts of the superior turbinate basal lamella intra-operatively. It also represents the first report of using the axial basal lamella of the superior turbinate as a landmark for the level of the sphenoid sinus ostium, as well as a landmark for the level of the skull base. The superior turbinate represents a constant landmark for performing a safe posterior ethmoidectomy and sphenoidotomy.