SURGICAL APPROACHES TO THE PITUITARY

Surgical Goals

1. Complete Resection of the Pituitary Adenoma
   • Corrects visual field defects
   • Cures hormone excess syndrome (e.g., acromegaly, Cushing disease)
2. Avoid Complications
   • Prevent cerebrospinal fluid (CSF) rhinorrhea
   • Prevent neurologic damage
3. Preserve Viable Pituitary Tissue
   • Avoid postoperative hypopituitarism

Determinants of Surgical Success

• Tumor Size, Location, and Consistency
  • Microadenomas (≤10 mm): ~80%–90% cure rate
  • Macroadenomas (>10 mm): ~50%–60% cure rate
  • >20 mm tumors: ~20% cure rate
• Cavernous Sinus Invasion
  • Typically prevents complete tumor removal.
• Suprasellar Extension
  • Adhesion to the optic chiasm/hypothalamus may limit resection and risk vision loss or hypothalamic damage.
• Tumor Consistency
  • Soft adenomas are more easily curetted; fibrous adenomas are more challenging.

HISTORICAL PERSPECTIVE OF PITUITARY SURGERY

1. Early 1900s
   • Sublabial transseptal transsphenoidal approach introduced.
   • Abandoned due to high infection-related mortality.
2. 1930s–1960s
   • Transfrontal Craniotomy was the main surgical route to the pituitary.
   • Associated with higher morbidity and mortality.
3. Late 1960s–1990s
   • Sublabial Transseptal Transsphenoidal Approach reintroduced.
   • Use of operative microscopes and antibiotics reduced infection risk.
   • Involved a sublabial incision and removal of the nasal septum to access the sphenoid sinus and sella turcica.
   • Common complications included nasal septal perforation, front teeth/upper lip numbness, and the need for nasal packing.
4. 1990s–Present
   • Direct Transnasal Transsphenoidal Approach (microscopic or endoscopic).
   • No external incision needed, avoids large septal disruption.
   • Shorter operative/anesthesia time, shorter hospital stay (~1 night).

DIRECT TRANSNASAL TRANSSPHENOIDAL APPROACH

Microscopic Technique

• Procedure
  1. A narrow speculum is placed into the nostril to reach the sphenoid ostia.
  2. A small mucosal incision is made at the posterior nasal passage (no major disruption to the septum).
  3. The sphenoid sinus is opened under microscopic vision to expose the sella turcica.
  4. The tumor is removed under direct microscopic view.

Endoscopic Technique

• Procedure
  1. A nasal endoscope is advanced through a nostril.
  2. The sphenoid ostium is enlarged, and the posterior vomer portion is removed, allowing access to the sphenoid sinus.
  3. A self-retaining nasal speculum is placed, and the sella is opened.
  4. The adenoma is resected under endoscopic visualization.
  5. The nasal speculum is withdrawn; the septum is adjusted, and a “mustache” dressing is applied.

Advantages

• No external incision
• Reduced nasal septal damage
• Faster operative time
• Lower postoperative discomfort and shorter hospital stay

POTENTIAL COMPLICATIONS

1. Intraoperative
   • Injury to the cavernous carotid artery
   • Injury to optic pathways
   • Injury to cranial nerves III, IV, V, and VI
   • CSF leakage
2. Postoperative
   • Sellar hematoma
   • CSF rhinorrhea
   • Meningitis
   • Hypopituitarism

ROLE OF THE TRANSCRANIAL APPROACH

• Indications
  • ~90% of sellar/parasellar tumors can be resected via the transnasal route.
  • Transcranial approach is reserved for lesions:
    • Extending into the middle fossa
    • Having large, complex suprasellar involvement