Endoscopic Marsupialization and Drainage of a Septated Sphenoid Sinus Mucocele in a Revision Skull Base Setting

Summary

This case report describes the endoscopic transnasal marsupialization of a septated sphenoid sinus mucocele in a revision case. It emphasizes landmark-based dissection, complete cavity unification, and safe drainage adjacent to critical skull base neurovascular structures.

Abstract

Sphenoid sinus mucoceles are rare lesions that account for less than 2% of all sinonasal mucoceles. In revision cases, surgery is more challenging because prior operations alter the normal anatomy and remove important surgical landmarks. A 79-year-old male presented with a headache 10 years after prior sphenoid surgery for fungal disease. Preoperative MRI showed a multiloculated, expansile sphenoid mucocele. Bony erosion involved the sellar floor and the right internal carotid artery (ICA) canal, with additional erosion of the mid-clivus. Endoscopic transnasal marsupialization was performed using the posterior choana and nasal septum as fixed landmarks to localize the sphenoid face. After entering the sphenoid sinus, the optic nerve prominence, ICA prominence, opticocarotid recess, and sella were identified on the posterior wall. A stepwise compartment-by-compartment approach was used to drain the mucocele and remove all septations under continuous visualization of these landmarks. The anterior sphenoid wall was completely removed to establish wide and durable drainage. All mucocele compartments were successfully drained. All posterior sphenoid landmarks were clearly identified. Bony dehiscence was noted at the sellar floor, mid-clivus, and right ICA canal. The dura was intact at all sites. No complications occurred. The headache improved after surgery. Follow-up confirmed a patent sphenoidotomy with no recurrence. This technique provides a safe and systematic approach to revision sphenoid mucocele surgery. It may be applied to other complex sphenoid lesions in which altered anatomy and skull-base dehiscence require careful landmark-based dissection.

Introduction

Sphenoid sinus mucoceles are rare, slowly expanding cystic lesions, accounting for less than 2% of all sinonasal mucoceles^1,2. They have high clinical importance due to their anatomical location and risk of severe complications^1,2. The sphenoid sinus has a close relationship with vital neurovascular structures, including the pituitary gland, optic nerves, internal carotid arteries (ICA), and cavernous sinuses^1,2. They usually develop in patients with previous sphenoid or transsphenoidal surgeries, and diagnosis is mostly delayed because they are usually present with vague, nonspecific symptoms such as headache, which is the most common complaint^3,4. More obvious symptoms present only when the mucocele is large and compressing adjacent structures. These symptoms include visual disturbances, diplopia, cranial nerve palsies, and hypopituitarism^2,5. Sphenoid sinus disease might present with significant skull base bony erosion or remodeling and intracranial extension on imaging, while the patient has only a few mild symptoms^5,6. MRI can show the characteristics of the sphenoid mucocele, septation, intracranial extension, and involvement of important structures such as the optic nerve, ICA, cavernous sinus, and pituitary gland^2,5.

The standard treatment for sphenoid mucocele is endoscopic transnasal marsupialization with drainage, which provides optimal exposure, direct visualization, and long-term drainage. It has a high success rate, a low recurrence rate, and significantly lower morbidity and complication rates compared to the open approach^1,2,7. Endoscopic sphenoid surgery has its own challenges due to its anatomical location and surrounding vital structures⁷. In revision cases, the surgery is more complex, especially after advanced sphenoid disease or transsphenoidal skull base surgery, because of altered anatomy, loss of normal landmarks, scarring, and new osteogenesis^2,3,8. In these cases, pre-operative imaging analysis and planning are essential^5,6. Intraoperatively, meticulous technique in identifying important landmarks such as the optic nerve and ICA prominences, the opticocarotid recess, the sella, and the clivus is essential for a safe approach and to avoid catastrophic complications^9,10. In this article, the authors present a case of sphenoid mucocele and describe endoscopic transnasal management of a multiloculated sphenoid mucocele secondary to previous sphenoid surgery for fungal disease. The main objective is to explain a safe technique to avoid complications and injuries to vital structures, and to provide complete marsupialization and drainage of the sphenoid mucocele.

Case presentation:
A 79-year-old male presented with a headache 10 years after prior sphenoid surgery for fungal disease. He had no significant systemic medical history. He remained asymptomatic for several years postoperatively before the headache gradually developed. On presentation, he was alert and oriented with no neurological deficits. Visual acuity and ocular motility were intact. Visual fields were full bilaterally. Nasal endoscopy showed posterior septectomy and sphenoidotomy. The middle and superior turbinates were absent bilaterally. A smooth, expansile bulge through the anterior sphenoid wall was identified, more prominent on the right. No sinonasal discharge or polyps were observed. The nasopharynx was clear of lesions or masses.

Diagnosis, Assessment, and Plan:
MRI of the paranasal sinuses and skull base was performed as the primary diagnostic investigation. T1- and T2-weighted sequences demonstrated a multiloculated, expansile lesion centered in the sphenoid sinus, predominantly on the right side and extending across the midline, with heterogeneous internal signal intensity and multiple internal septations. There was expansion and bony erosion involving the sellar floor, right ICA canal, and mid-clivus, with the pituitary gland, right ICA, and basilar artery intact. The bilateral paraclival ICA segments were visible flanking the mid-clival region, with the right paraclival ICA in closest proximity to the inferior portion of the lesion. No intracranial extension, cavernous sinus invasion, or posterior fossa involvement was identified. The imaging characteristics and surgical history were most consistent with a sphenoid mucocele. Endoscopic transnasal marsupialization and drainage of the sphenoid sinuses were planned as definitive treatment. 

Protocol

This protocol was performed in compliance with the institutional guidelines for human research ethics. This study was conducted in accordance with the Declaration of Helsinki. Ethical approval was obtained from the Taif University Ethical Committee (Approval No. HAPO-02-T-105).

1. Preoperative preparation and imaging review

1. Preoperative magnetic resonance imaging (MRI) of the paranasal sinuses and skull base was obtained and reviewed using T1- and T2-weighted panels. Lesion characteristics were identified, including mucocele content, septation pattern, and the full extent of sinus involvement.
2. All areas of bony dehiscence, erosion, or compression were identified and documented on imaging. Specific attention was given to the optic nerve canal, the ICA canal, the sellar floor, and the clivus.

2. Patient positioning and setup

1. The patient was placed supine with the head elevated in the reverse Trendelenburg position. The head was fixed, and the neck was kept in a neutral position.
2. General anesthesia was administered using a total intravenous anesthesia (TIVA) protocol to minimize mucosal bleeding. Bilateral ocular lubricant was applied, and the eyelids were taped closed. Both eyes remained visible to the surgeon throughout the procedure.
3. A 0-degree rigid endoscope (4 mm diameter) was prepared, and image quality was verified. A 30-degree and a 45-degree endoscope were also available for inspection of lateral recesses or lesion extensions.
4. Surgical instruments were prepared, including a Freer septum elevator, Kerrison punch, straight and curved suction devices, straight and angled through-cutting forceps, Blakesley forceps, curved curettes, and bipolar and monopolar electrocautery.
5. Resorbable hemostatic material and neurosurgical patties were confirmed to be available in the field (see Table of Materials).

3. Exposure and initial nasal approach

1. The 0-degree endoscope was inserted into both nasal cavities sequentially.
2. A systematic inspection of the nasal anatomy was performed, including all turbinates, the nasal septum, the sphenoid ostium, and all postoperative changes from prior surgery.
   NOTE: If synechiae are present, they should be removed, and the middle turbinate lateralized before advancing the endoscope posteriorly.
3. A posterior septectomy had been performed during the previous surgery, and the sphenoid ostia were absent. The posterior choana and nasal septum served as constant anatomical landmarks to identify the sphenoid face, which also formed the anterior wall of the mucocele.
4. The midline was localized using the nasal septum. The area of maximal bulging through the sphenoid face was identified. The most inferomedial and prominent portion of the anterior wall was selected as the entry point.
   NOTE: If no prior posterior septectomy has been performed, make a Killian incision near the bony-cartilaginous junction of the nasal septum. Elevate the mucoperiosteal flap with a septum elevator in the subperiosteal plane. Advance posteriorly toward the sphenoid rostrum, keeping the elevator in contact with bone, until the sphenoid keel is fully exposed and both sphenoid ostia are identified. Cauterize the mucosa around the sphenoid ostia with suction diathermy. Enlarge the sphenoid inferomedially with a Kerrison punch, weaken the rostrum, and remove it with Blakesley forceps to gain entry into the sphenoid sinus.

4. Marsupialization of the mucocele

1. The planned entry site was cauterized using bipolar diathermy to minimize bleeding. An incision was made at the identified entry point using a Freer elevator, and the opening was carefully widened to access the mucocele cavity.
2. The mucocele contents were aspirated with straight suction. The cavity was emptied completely. All aspirations were performed under direct endoscopic vision.
3. After initial drainage of the first mucocele compartment, the posterior sphenoid wall landmarks were carefully identified.
4. The optic nerve prominence, the ICA prominence, the opticocarotid recess (OCR), and the sella were identified on the posterior wall. Each landmark was confirmed before proceeding.
5. The mucocele septa were removed while maintaining continuous visualization of the posterior sphenoid landmarks.
6. Dissection proceeded medially first, then laterally, aspirating contents from each compartment in sequence. After clearing the septa and contents inferiorly, the mid-clivus and sphenoid floor were identified.
7. For each compartment, the septation was opened, and the contents were completely evacuated. All anatomical landmarks were reassessed before proceeding. A curved suction was used to aspirate the lateral extensions.
   NOTE: If a lateral recess is present, identify the maxillary nerve (V2) landmark superiorly and the vidian nerve landmark inferiorly as orientation guides for safe lateral dissection.
   CAUTION: When a septation is attached to or near the ICA prominence, divide it using through-cutting forceps in a clean through-and-through cut only. Avoid any manipulation, traction, or cracking of bone in this region. Never instrument directly over the ICA prominence.
8. The dehiscent bone of the skull base was evaluated throughout the dissection, and the underlying dura was confirmed to be intact at all sites of bony dehiscence before proceeding.
9. All remaining septations were removed, and mucocele contents were evacuated, with continuous visualization of sphenoid landmarks throughout.
10. Dissection continued until all sphenoid sinus walls were clearly visualized, the cavity was fully marsupialized, and no residual compartments remained.

5. Establishing adequate drainage

1. The sphenoidotomy was further widened to ensure a wide, durable drainage pathway.
2. The residual bone margins of the sphenoid face were removed with through-cutting forceps and a Kerrison punch.
3. The drainage was extended inferiorly to the sphenoid floor.

6. Final endoscopic inspection

1. A comprehensive endoscopic examination of the entire sphenoid sinus cavity was performed, with no residual mucocele material or septations. The sinus was widely opened and successfully drained.
2. All important anatomical landmarks were clearly visualized, including the ICA prominences bilaterally, the optic nerve prominences bilaterally, the opticocarotid recesses on both sides, as well as the sellar floor and clivus.
3. Each area of bony dehiscence was carefully examined, confirming dural integrity at every site. Hemostasis was then achieved.

Results

A 79-year-old male presented with a headache. He had no neurological deficits. He had undergone prior sphenoid surgery for fungal disease 10 years earlier. Magnetic resonance imaging demonstrated a multiloculated, expansile lesion centered in the sphenoid sinus, predominantly on the right, extending across the midline, with heterogeneous internal signal intensity and multiple internal septations (Figure 1A–B). Bony erosion involved the sellar floor and right ICA canal. The p...

Discussion

This case illustrates key principles for the safe endoscopic management of a sphenoid sinus mucocele in a revision setting. Revision sphenoid surgery is more challenging than primary surgery. Prior operations cause altered anatomy, scarring, and bony remodeling^11,12. The middle and superior turbinates may have been removed. The sphenoid ostia are often stenosed or obliterated^11,12. Prior sphenoid fungal d...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Bipolar Forceps 23 cm, bayonet, 1.2 mm	Karl Storz	28163BPL	Bipolar diathermy, Hemostasis
BLAKESLEY  Nasal Forceps, size 4, 11 cm	Karl Storz	456004	Sphenoid rostrum removal; straight tissue removal
Centricity PACS System	GE HealthCare	7.0 SP2.01	MRI images view
Curette, 2 mm, working length 13 cm	Karl Storz	28164KLH	For  dissection, Exposure
FREER Elevator, double-ended	Karl Storz	474000	Mucoperiosteal flap elevation; mucocele entry
GELFOAM Absorbable Gelatin Sponge	Pfizer	09-0353-01	Gelatin sponge packing and hemostasis
HOPKINS Telescope, 0°, ø 4 mm, length 18 cm	Karl Storz	28132 AA	Primary endoscope for all phases
HOPKINS Telescope, 30°, ø 4 mm, length 18 cm	Karl Storz	28132 BA	Angled view into sphenoid sinus and lateral recesses
HOPKINS Telescope, 45°, ø 4 mm, length 18 cm	Karl Storz	28132 FA	Angled view into sphenoid sinus and lateral recesses
Insulated Cannula for Suction & Coagulation, 3 mm, WL 16 cm	Karl Storz	28164 MXB	Suction diathermy, Hemostasis
Insulated Cannula for Suction & Coagulation, curved, 2.5 mm	Karl Storz	28164 MXA	Suction diathermy, Hemostasis
Kerrison Punch, upbiting 60°, 2 mm, WL 17 cm	Karl Storz	28164 MKB	Sphenoid bone removal and sphenoidotomy widening
Kerrison Punch, upbiting 60°, 3 mm, WL 17 cm	Karl Storz	28164 MKC	Sphenoid bone removal and sphenoidotomy widening
Nasal Forceps, through-cutting, jaws angled up 45°	Karl Storz	28164 UB	Angled through-cutting; septation near ICA
NasoPore nasal dressing	Stryker	5400-020-108ITL	Resorbable packing and hemostasis at end of case
Neurosurgical Cottonoid Patties, X-ray detectable	Integra / Codman	801407	Intra-oprative packing and hemostasis
Scalpel Blade No. 15	Bard-Parker	371615	Killian incision
Scalpel Handle No. 3	Bard-Parker	371030	Holds No. 15 blade
Suction Tube, straight, 9 Charr., WL 15 cm	Karl Storz	28164 XG	Straight suction for mucocele contents drainage, large bore
Suction Tube, tip curved upwards, 8 Charr.	Karl Storz	28164 XC	Curved suction; lateral recess aspiration
Throughcutting Forceps, 18 cm, straight	Karl Storz	28164GS	Straight through-cutting; septation removal