Study population
This single-centre retrospective study enrolled 41 patients who underwent endoscopic modified transseptal pituitary surgery between April 2018 and December 2019 at our hospital. The main inclusion criterion was primary/recurrent pituitary adenoma, with olfactory testing performed both preoperatively and 3 months postoperatively. The exclusion criteria were endoscopic surgery combined with craniotomy, endoscopic sinus surgery (ESS) performed intraoperatively/previously performed, chronic rhinosinusitis (CRS) with/without nasal polyp, and allergic rhinitis. All surgeries were performed by the same otolaryngologist (O.K.) and neurosurgeons (I.Y., M.R.). The research protocol was approved by the institutional ethics committee (Protocol No. 32-081). Written informed consent was obtained from all patients.
Surgical approach (video 1)
We chose a bi-nostril approach, with the left nostril approaching the sphenoid sinus via the nasal septum and the right nostril approaching the sphenoid sinus via the nasal cavity and olfactory cleft. A surgical field of passage and approach to the sphenoid sinus was devised at our centre by an otolaryngologist. First, an incision was made in the left nasal septum mucosa from the anterior superior to the nasal floor. The mucosa of the left nasal septum and nasal floor was raised from the nasal septal cartilage and maxillary bone and pulled into the left limen nasi, allowing a visual field to approach the sphenoid sinus via the nasal septum. At this time, the greater palatine artery passing through the canalis incisivus was not dissected (Fig. 1A). Second, septoplasty was performed with the vomer and perpendicular plate of the ethmoid removed. At the posterior edge of the nasal septum, an incision was made from the nasal floor along the upper walls of the right and left choana to increase the lateral range of motion of the left and right nasal septal mucosa. The left and right nasal septal mucosa were laterally deviated, and sphenoidotomy was performed until the bilateral sides of the optic canal and carotid artery ridges were in the same endoscopic field of view. (Fig. 1B). Third, the right nasal septal mucosa was incised horizontally (posteriorly to anteriorly) with the nasal floor from the upper margin of the sphenoid sinus ostium to the anterior end of the middle turbinate (Fig. 1C). No turbinate was resected in any of the cases. The posterior ethmoidal sinus may be opened by endoscopic ethmoidectomy in cases of pituitary tumours that extend laterally beyond the cavernous sinus at grade ≥3 according to Knosp classification.18 A 1 mm-thick silicone plate (KOKEN, Tokyo, Japan) was placed on the outside of the left and right nostrils to protect the left nasal septal mucosa and right inferior/middle turbinate and sewn into the nostrils on both sides. This allows for a two-nostril, one-cavity approach (Fig. 1D). The sphenoid sinus mucosa, which we call a local flap, was temporarily peeled off and preserved to cover the wound finally, and the patient then underwent tumour removal by the neurosurgical team. After pituitary tumour removal and confirmation that there was no cerebrospinal fluid (CSF) leak, osteophyte and mucosal reconstructions with a local flap were performed. In cases of intraoperative CSF leakage, the horizontal incision in the right nasal septal mucosa was extended and an NSF was prepared. If an NSF was not used, the right-sided horizontal incision was sutured with two stitches using 5-0 TF vicryl. The left-sided septal mucosal incision line was sutured with three stitches, and the left and right nasal septa were sutured together with three stitches using 4-0 RB-1 vicryl. Finally, the left and right nasal septal mucosa were sutured with 5-0 nylon thread to sandwich the silicone plate. Nasal rinsing was initiated 1 week postoperatively, and the silicone plate was removed 1 month postoperatively.