Approaches for Hypophysectomy

1. Transsphenoidal Approaches (Extracranial) - PREFERRED

A. Transnasal Transsphenoidal (Microscopic)

• The traditional approach, popularized by Jules Hardy in 1965 using an operating microscope and fluoroscopy
• A speculum is passed through one nostril, through the nasal septum, into the sphenoid sinus, and then through the sella turcica floor
• No external incision; direct midline access to sella
• Requires a well-pneumatized sphenoid sinus

B. Sublabial Transsphenoidal (Microscopic)

• Incision made in the upper gum (sublabial), underneath the upper lip
• The nasal septum is elevated submucosally and a speculum passed through the sphenoidal ostium
• First popularized by Harvey Cushing in 1910
• Provides a wider working angle than transnasal, but more mucosal disruption and numbness of upper teeth/lip postoperatively
• Less commonly used today

C. Transnasal Endoscopic (Endonasal) - Most Modern

• Introduced in the 1990s; now the dominant technique in most pituitary centers
• A rigid endoscope (0° and angled) is passed through the nostril(s) directly to the sphenoid
• Binostril (four-handed) technique allows simultaneous use of two surgeons (neurosurgeon + ENT)
• Provides wider panoramic visualization of the sella, parasellar, and suprasellar regions
• Better visualization of lateral recesses and cavernous sinus compared to microscopic approaches
• No lip incision; shorter hospital stay; minimal morbidity
• Expanded endoscopic endonasal approaches (EEA) can address suprasellar, clival, and craniopharyngeal tumors

D. Transmaxillary Transsphenoidal

• Combines transsphenoidal with a transmaxillary (Caldwell-Luc) route
• Used for very large tumors requiring wider exposure
• Less commonly used today

D. Trans-ethmoido-sphenoidal

• External ethmoidectomy approach through the medial orbital wall
• Historical interest; largely replaced by endoscopic techniques

2. Transcranial Approaches

A. Pterional (Frontotemporal) Approach

• Most commonly used transcranial approach today
• A frontotemporal craniotomy is performed; part of the sphenoid wing is removed
• Requires minimal brain retraction; provides the shortest trajectory to the parasellar region
• Excellent visualization of the pituitary gland, optic chiasm, and cavernous sinus
• Preferred over subfrontal approach for most transcranial cases

B. Subfrontal (Anterior) Approach

• Bifrontal or unilateral frontal craniotomy
• Provides direct visualization of the pituitary tumor between the optic nerves
• Less popular than pterional because of risk to olfactory nerves and possible entry into the frontal sinus
• Used for midline suprasellar tumors (e.g., craniopharyngiomas) with anterior extension
• Also called "transfrontal hypophysectomy" - used when suprasellar extension makes transsphenoidal approach inadequate (Miller's Anesthesia)

C. Subtemporal Approach

• Historical approach (first attempted by Caton and Paul in 1893 with lateral subtemporal route)
• Rarely used now; access through the middle fossa floor
• High risk of temporal lobe retraction injury

D. Orbitozygomatic Approach

• Extended craniotomy removing the orbital rim and zygomatic arch
• Provides wider exposure with less brain retraction for very large, complex tumors
• Reserved for giant tumors with complex vascular relationships

3. Stereotactic Radiosurgery (Non-Surgical Ablation)

• Gamma Knife Radiosurgery - most common; multiple convergent gamma rays target the tumor
• CyberKnife / LINAC-based radiosurgery - frameless, robotically guided
• Proton beam therapy - charged particle therapy for more precise dose delivery

• Residual or recurrent pituitary adenomas after surgery
• Cushing's disease (ACTH-secreting adenomas)
• Acromegaly (GH-secreting adenomas)
• Patients unfit for surgery

Comparison Summary

Indications for Transcranial over Transsphenoidal

1. Suprasellar component is giant or encases optic nerves/arteries
2. Fibrous adenoma with large suprasellar extension (predicted on T2 MRI)
3. Active sinus infection (contraindication to transsphenoidal)
4. Unsella-enlarged sella making transsphenoidal access unreliable
5. Previous failed transsphenoidal surgery with scarring

Postoperative Considerations

• Glucocorticoids (most urgent - secondary adrenal insufficiency)
• Thyroid hormone (secondary hypothyroidism)
• Sex hormones (gonadotropin deficiency)
• ADH/desmopressin if diabetes insipidus develops (posterior pituitary involvement)
• Growth hormone replacement as needed