Sphenoid Sinus Surgery

Sphenoid Sinus Surgery

Sphenoid Sinus Surgery

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Sphenoid Anatomy - Danger Zone Map

  • Boundaries & Relations:
    • Roof: Sella turcica, pituitary gland, optic chiasm.
    • Floor: Nasopharynx, roof of choana.
    • Anterior wall: Sphenoethmoidal recess, posterior nasal septum.
    • Posterior wall: Clivus, basilar artery.
    • Lateral wall: Cavernous sinus, Internal Carotid Artery (ICA), Optic Nerve (ON), Maxillary Nerve (V2), Vidian nerve.
  • Key Neurovascular Structures (Danger Zones):
    • Optic Nerve: Superolateral; average ~18 mm from anterior sphenoid wall. High risk of dehiscence.
    • Internal Carotid Artery (ICA): Posterolateral (cavernous & clinoidal segments); average ~15-22 mm from anterior wall. Dehiscence common.
    • V2 (Maxillary Nerve): Inferolateral; passes through foramen rotundum.
    • Vidian Nerve (Nerve of Pterygoid Canal): Inferolateral; in vidian canal.
  • Common Anatomical Variations:
    • Onodi cell (sphenoethmoidal cell): Most posterior ethmoid cell, superolateral to sphenoid sinus; closely related to ON & ICA.
    • Lateral recess: Extensive pneumatization into greater sphenoid wing or pterygoid process.

Sphenoid sinus anatomy and surrounding neurovasculature

⭐ > The prevalence of optic nerve or carotid artery dehiscence in the sphenoid sinus wall is a significant surgical risk, reported in up to 25% of cases for the ICA and 20% for the optic nerve depending on studies and sinus pneumatization type (e.g., conchal, presellar, sellar, postsellar).

Surgical Access - Path Choice Pro

Indications for Surgery:

  • Chronic sphenoid sinusitis refractory to medical therapy.
  • Sphenoid mucoceles, pyoceles, or fungal balls.
  • Repair of CSF leaks originating from the sphenoid sinus.
  • Surgical access for pituitary tumors (e.g., craniopharyngioma) and skull base lesions (e.g., chordoma).

Contraindications:

  • Absolute: Active systemic/local infection, uncorrected coagulopathy.
  • Relative: Medically unstable patient, severe uncontrolled comorbidities.

Pre-operative Workup:

  • CT PNS (axial, coronal, sagittal): Essential for bony anatomy, disease extent, identifying key structures (optic nerve, carotid artery).
  • MRI: Indicated if tumor, fungal infection, or intracranial/orbital complications are suspected.
  • Diagnostic Nasal Endoscopy: To assess nasal anatomy, mucosa, and identify associated pathologies like polyps or discharge.

⭐ The transnasal transostial approach is the most common and direct route for isolated sphenoid sinus pathology.

Coronal view of nasal anatomy and polyps

The Procedure - Deep Dive Guide

  • Anesthesia & Positioning:
    • General Anesthesia (GA) with controlled hypotension.
    • Patient: Supine, reverse Trendelenburg.
  • Key Surgical Steps:
    • Nasal decongestion (topical vasoconstrictors).
    • Identify sphenoid ostium. 📌 Landmarks: Superior Turbinate (ST), septum, choana. (Ostium is medial to ST, superomedial to choana).
    • Sphenoidotomy: Widen natural ostium or perform anterior sphenoidotomy.
    • Complete removal of pathology.
    • Ensure sinus ventilation; achieve meticulous hemostasis.
  • Essential Instruments:
    • Endoscopes: 0, 30, 45-degree.
    • Kerrison rongeurs, microdebrider, suction Freer.
    • Image Guidance System (IGS): For complex/revision cases, or skull base extension.

⭐ The sphenoid ostium is typically located medial to the superior turbinate and superomedial to the choana.

Post-Op & Pitfalls - Recovery Road

  • Post-Operative Care:
    • Nasal packing: Absorbable; non-absorbable out in 24-48 hrs.
    • Meds: Systemic antibiotics, systemic/topical steroids, analgesics.
    • Nasal hygiene: Regular saline douching.
  • Follow-Up:
    • Scheduled endoscopic debridement (prevents adhesions, clears crusts).
  • Complications:
    • Intra-op: ICA injury (⚠️ catastrophic!), optic nerve/orbital injury, CSF leak, V2/vidian nerve damage, bleeding.
    • Post-op: Delayed epistaxis, infection, sinusitis, mucocele, adhesions/synechiae. ENS (rare).
  • Management of CSF Leak:
    • Conservative: Bed rest, head up 30°, avoid strain. Lumbar drain if persistent.
    • Surgical repair: For large defects or failed conservative approach.

⭐ Vascular injury, particularly to the ICA, is the most feared complication of sphenoid sinus surgery.

Sphenoid sinus anatomy and critical structures

High‑Yield Points - ⚡ Biggest Takeaways

  • Endoscopic transnasal approach is the gold standard for sphenoid sinus surgery.
  • Critical structures: Optic nerve (ON) and internal carotid artery (ICA) are at high risk.
  • Onodi cell, if present, ↑ risk to ON/ICA; meticulous pre-op CT review is vital.
  • Common indications: Isolated sphenoid disease, sphenochoanal polyps, pituitary tumor access.
  • Potential complications: ON/ICA injury, CSF leak, meningitis, cavernous sinus issues.
  • Sphenoid ostium is the primary surgical entry point, typically medial to superior turbinate_._

Practice Questions: Sphenoid Sinus Surgery

Test your understanding with these related questions

A lady comes to OPD after fall from scooty. Her vitals are stable. She is having continuous, clear watery discharge from nose after 2 days. This is most likely a feature of?

1 of 5

Flashcards: Sphenoid Sinus Surgery

1/10

In septoplasty, mucoperichondrial/mucoperiosteal flaps are raised on _____ side(s)

TAP TO REVEAL ANSWER

In septoplasty, mucoperichondrial/mucoperiosteal flaps are raised on _____ side(s)

both (one/both)

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Sphenoid Sinus Surgery - Free Indian Medical PG Review