Effectiveness of a Modified Transsellar Approach with Planum Sphenoidale Removal for Pituitary Neuroendocrine Tumors with Anterosuperior Extension

<b>Background/Objectives:</b> Achieving gross total resection is crucial in the surgical management of pituitary neuroendocrine tumors (PitNETs). However, PitNETs with anterosuperior extension remain challenging to completely remove using the conventional transsellar approach (TSA) due to limited access to the anterior suprasellar region. This study evaluated the efficacy and safety of a modified TSA (mTSA) that involves additional removal of the tuberculum sellae and planum sphenoidale (PS) bones without expanding the dural incision. <b>Methods:</b> We retrospectively reviewed 104 patients with nonfunctioning PitNETs who underwent endoscopic transsphenoidal surgery between 2017 and 2022. Seventy-seven patients were treated with the conventional TSA and 27 with the mTSA. Tumor configuration and accessible area were measured on pre- and postoperative MR imaging and CT. The ratio of the accessible to total tumor area was calculated on mid-sagittal images. Surgical outcomes and postoperative complications were compared between groups. <b>Results:</b> Gross total resection was achieved in all patients. Tumors treated with mTSA were larger (median height, 32 mm vs. 25 mm; <i>p</i> < 0.001) and showed greater anterosuperior extension. The mTSA increased the median accessible tumor area from 70% to 88%, with a median PS removal distance of 4.4 mm. Postoperative complications were minimal: cerebrospinal fluid leakage (3%), meningitis (3%), transient ocular movement disturbance (2%), and transient visual worsening (1%). No hemorrhage or anosmia occurred. <b>Conclusions:</b> The mTSA safely expands the surgical corridor to the anterior suprasellar region, enhancing accessibility and enabling complete resection without dural incision. This approach balances surgical radicality and safety in PitNETs with anterosuperior extension.