Endoscopic endonasal approach for pituitary neuroendocrine tumor with septal mucosa incision tailored to tumor extension intending unilateral septal mucosa preservation

Currently, the direct endonasal approach is widely used in endoscopic endonasal surgery (EES) for pituitary neuroendocrine tumor. However, a large posterior septal perforation is inevitable. We routinely utilize a modified para/transseptal approach using the combination of a Killian and a contralateral rescue flap incision (PTSA with K-R incision). Especially, rescue flap incision is used on ipsilateral side of the tumor extension to facilitate lateral expansion of the anterior sphenoidotomy and tumor resection. One hundred eighty-nine patients underwent EES using PTSA with K-R incision in Tsukuba university hospital. Gross total resection (GTR) was achieved in 146 (77.2%) patients. Even in cases of significant lateral tumor extension (Knosp 3 or 4), GTR was achieved in 56 of 90 (62.2%) patients. Among the 168 patients with available rhinological follow-up data, postoperative anterior and posterior septal perforation occurred in six (3.6%) and 18 (10.7%) patients, respectively. Surgical intervention was required in one (0.6%) patient with anterior septal perforation. Thus, PTSA with K-R incision was effective in preserving the nasal septal mucosa on one side and gaining a sufficient surgical corridor with lateral expansion of the anterior sphenoidotomy on the other side. Our strategy may be preferable to improve maneuverability of instruments during tumor resection.