Endoscopic Endonasal Transsphenoidal

Transsphenoidal surgery was refined with the operating microscope through a sublabial or transseptal route. In the 1990s, fully endoscopic techniques were developed, and Jho and Carrau reported one of the first large endoscopic endonasal series^[1]. The endoscope brings a wide, angled, close-up view into the sella and the parasellar region, and de Divitiis and Cappabianca showed that the technique could be adapted to the full range of sellar lesions^[2]. Kassam and colleagues then described a modular expanded endonasal approach (EEA) along the sagittal plane, from the crista galli to the sella and from the dorsum sellae to the foramen magnum^[3,4].

• Standard transsellar: pituitary adenomas, Rathke cleft cysts and other intrasellar lesions.
• Transtuberculum/transplanum: suprasellar craniopharyngiomas, tuberculum sellae and planum meningiomas.
• Transcribriform: olfactory-groove meningiomas, esthesioneuroblastomas and sinonasal malignancies.
• Transclival: chordomas, chondrosarcomas and selected petroclival lesions.
• Transodontoid: ventral craniocervical compression.
• Transpterygoid: lateral sphenoid recess encephaloceles, Meckel's cave and petrous apex lesions.

Inside the sphenoid sinus the posterior wall shows the sellar floor in the centre, the carotid protuberances laterally, the optic protuberances superolaterally, and between them the lateral opticocarotid recess, which corresponds to the optic strut. The medial opticocarotid recess marks the junction of the tuberculum and the planum. The intercavernous sinuses lie in the dura at the top and bottom of the sella. The paraclival carotid arteries run vertically lateral to the clival recess, and the vidian canal at the floor of the sphenoid sinus leads back to the anterior genu of the petrous carotid^[5].

• Decongest the nasal mucosa; lateralise the inferior and middle turbinates, and remove the right middle turbinate if wide exposure is needed.
• Harvest a pedicled nasoseptal flap at the start when a high-flow leak is expected, based on the posterior septal artery^[6].
• Perform a posterior septectomy and wide sphenoidotomy so that two surgeons can work with up to four hands through both nostrils.
• Remove the sphenoid septations, taking care where they insert onto the carotid prominences.
• Open the sellar floor from cavernous sinus to cavernous sinus; use Doppler to confirm the carotid position before opening the dura.
• Resect the lesion, using angled endoscopes to inspect for residual tumour.
• Reconstruct in layers (inlay, onlay, vascularised flap, sealant) according to the size of the defect and the CSF flow.

• CSF leak: the most frequent problem in expanded approaches; the vascularised nasoseptal flap reduced leak rates substantially^[6]. Lumbar drainage is used selectively.
• Internal carotid artery injury: rare but catastrophic; prevent with navigation, Doppler and respect for the parasellar anatomy, and prepare a plan (packing, a muscle patch, endovascular occlusion or stenting).
• Endocrine: transient diabetes insipidus, SIADH and new hypopituitarism.
• Visual worsening: from manipulation or ischaemia of the chiasm; preserve the superior hypophyseal arteries.
• Sinonasal morbidity: crusting, synechiae, anosmia and septal perforation; nasal care improves recovery.