Sphenoidotomy 

Updated: Dec 19, 2018
Author: Thomas S Higgins, Jr, MD, MSPH; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Background

Sphenoidotomy is the surgical opening of the sphenoid sinus.

The sphenoid sinuses are central aerations of the sphenoid bone that start developing at about 3 months’ gestation. Their development initiates as a vagination of the cartilaginous cupular process and continues to enlarge until the teenaged years.

Because of the high variability of sphenoid sinus pneumatization, the boundaries can differ from person to person.

The anterior boundaries of the sphenoid sinus are likely the most consistent. They include the sphenoid crest anterosuperiorly, which articulates with the perpendicular plate of the ethmoid bone, and the rostrum anteroinferiorly, which articulates with the vomer. The posterior boundaries of the sphenoid sinus usually include the sella turcica medially and cavernous sinuses laterally.

Hamberger described 3 types of pneumatization based on its relationship to the sella turcica: conchal (rudimentary or absent sphenoid sinus), presellar (a posterior sphenoid sinus wall that is separated from sella by thick bone), and sellar (a posterior sphenoid sinus wall that is adjacent to sella).[1] The most common configuration in his series was the sellar type, found in 86% of the population, compared to the presellar type (11%) and conchal type (3%).

Authors have described a quite common fourth configuration, postsellar type, in which sphenoid sinus extends beyond the sella turcica so that the sella forms a portion of the roof of the sphenoid sinus. In addition, the optic chiasm and internal carotid arteries are often intimately associated with posterior or lateral walls of sphenoid sinus.

The lateral limits of the sphenoid sinus vary greatly. The inferolateral area of the sphenoid sinus carries the vidian nerve, and the superolateral area carries V2 in foramen rotundum.

Coronal computed tomographic image of the sphenoid Coronal computed tomographic image of the sphenoid sinus demonstrating the location of cranial nerve V2 and the vidian nerve.

The lateral extent of the sphenoid sinus may extend to or beyond these nerves. The posterior septal branch of the sphenopalatine artery runs a few millimeters below the natural os of the sphenoid sinus.

Indications

The indications for sphenoidotomy include acute and chronic sphenoid rhinosinusitis that is refractory to medical therapy; sphenoid mass or lesion; endonasal skull base or pituitary surgery; sphenoid cerebrospinal fluid leak repair; endonasal vidian neurectomy; and optic nerve or orbital decompression.[2, 3]

Contraindications

Sphenoidotomy has no absolute contraindications.

Relative contraindications include comorbidities that limit general anesthesia or conditions that increase the risk of bleeding. Care should also be taken when performing surgery on a hypoplastic sphenoid sinus or sphenoid sinus cavities with dehiscence of the internal carotid artery or optic nerve.

Technical Considerations

Procedure Planning

Preoperative imaging should include noncontrast CT scanning of the sinuses to provide information about the bony architecture and pneumatization patterns of the sphenoid sinus. Other imaging studies may be advisable depending on the particular disease being managed. The characteristics that should be evaluated with regard to the sphenoid sinus prior to performing a sphenoidotomy include the following:

  • Pneumatization pattern in relation to the sella turcica (conchal, presellar, sellar, postsellar)

  • Location of the natural ostium and its relationship to the superior turbinate (the image below demonstrates a right-sided sphenoid sinus natural ostium located medial to the superior turbinate)

    Unoperated right-sided sphenoid sinus os with mucu Unoperated right-sided sphenoid sinus os with mucus discharge. The sphenoid os can be seen located just medial to the superior turbinate in this case.
  • Location of the optic nerve, optic chiasm, and internal carotid artery with particular attention to presence or absence of bony dehiscence

  • Presence or absence of a posterior ethmoid (Onodi) cell

Complication Prevention

Prior to performing sphenoidotomy, the surgeon should carefully inspect the patient’s anatomic variants and extent of sinusitis. The surgeon should also use a standard approach that allows safe entrance into the sphenoid sinus. Stereotactic navigation should be considered, when warranted. In an effort to avoid severe complications, the surgeon should recognize potential pitfalls, such as cerebrospinal fluid leaks from inadvertent skull base injury, blindness from optic nerve injury, hemorrhage from the posterior septal branch of the sphenopalatine artery, or catastrophic hemorrhage from the internal carotid artery.

Regardless of the technique performed, care should be taken to avoid vital structures. The optic nerve may traverse laterally, and sometimes superiorly, in proximity to the sphenoid sinus or within an Onodi cell. Care should especially be taken to avoid disturbing the posterior wall of the sphenoid sinus, as this can risk injury to the carotid artery, optic chiasm, cavernous sinus, or pituitary gland. In addition, the surgeon should be aware that the posterior septal branch of the sphenopalatine artery traverses just inferior to the nature os of the sphenoid sinus; thus, removal of bone and mucosa inferiorly may cause inadvertent injury to this artery with resultant epistaxis. Some ways to avoid injury to this artery include elevating the mucosa off the bone or cauterizing the approximate site of the artery prior to performing inferior dissection. If bleeding is encountered secondary to this artery, it is fortunately readily controlled with monopolar or bipolar cauterization.

Outcomes

Sphenoidotomy appears efficacious based on case series studies.[4] No prospective randomized controlled trials have evaluated sphenoidotomy.

 

Periprocedural Care

Patient Education & Consent

The risks, benefits, alternatives, and complications should be discussed with the patient before undergoing any procedure. The risks of endoscopic sphenoidotomy include, but are not limited to, the following:[5, 6]

  • Bleeding

  • Infection

  • Anesthetic risks

  • Scarring

  • Recurrence of disease

  • Skull base injury, cerebrospinal fluid leak, and meningitis

  • Eye or vision loss and orbital nerve or optic chiasm injury

  • Carotid artery injury

  • Postoperative ostial stenosis

  • Mucocele formation

Equipment

Equipment involved in sphenoidotomy includes the following:

  • Endoscope or microscope

  • Suction

  • Nasal curette

  • Nasal thru-cutting or grasping forceps

  • Sphenoid mushroom punch

  • Kerrison punch

  • Sickle knife

  • Microdebrider (judicious use only)

  • Image guidance probe

  • Drill (for severe osteitis or pituitary tumor approaches)

Patient Preparation

Anesthesia

Sphenoidotomy, along with other components of a functional endoscopic sinus surgery, is usually performed under general anesthesia. There are rare occasions when a surgeon may elect to perform a sphenoidotomy under local anesthesia in the operating suite or office setting.

Positioning

The patient is positioned in the standard supine positioning for endoscopic sinus surgery. Each surgeon has preferences for positioning. Some head positions that may assist the surgeon include elevating the head or reverse Trendelenburg positioning and tilting the head toward the surgeon.

Monitoring & Follow-up

The postoperative management of a endoscopic sphenoidotomy is similar to that of other procedures in functional endoscopic sinus surgery. Patients are often asked to perform nasal saline irrigations or lavages several times a day. Postoperative antibiotics and oral corticosteroids are given per surgeon preference.

Patients are usually seen in clinic for nasal endoscopy with debridement at about 1-2 weeks after surgery. The debridement of crusts and blood clots, as well as the early identification of scar tissue, helps limit postoperative adhesions.

 

Technique

Approach Considerations

Several specific sphenoid procedures may be performed. Some procedures, including lavage of the sphenoid sinus and diagnostic sinuscopy, provide access to the sphenoid sinus without requiring surgical sphenoidotomy. Surgical dilation of the sphenoid ostium is a minimally invasive approach to widen the sinus ostium without removing tissue.[7, 8]

Sphenoidotomy is the surgical opening of the sphenoid sinus. Sphenoidotomy may be performed without (CPT#31287) or with (CPT#31288) tissue removal. The designation of "tissue removal" has been defined by the American Academy of Otolaryngology-Head and Neck Surgery as removal of material or tissue, not just suctioning of mucus or pus.

The techniques for endoscopic sphenoidotomy may be divided into (1) transethmoidal versus transnasal approach and (2) opening via the natural os versus through the anterior sinus wall.

The image below demonstrates a sphenoidotomy site 6 weeks postoperatively.

Left-sided sphenoidotomy site at 6 weeks postopera Left-sided sphenoidotomy site at 6 weeks postoperatively from removal of sphenoid sinus fungal ball.

The size limitations of the sphenoidotomy depend on the size of the sphenoid sinus. The optimal size of the sphenoidotomy is unknown; however, it is generally considered important to perform wider sphenoidotomies in obstructive sinonasal disease such as polyposis and allergic fungal sinusitis. Expanded endonasal approaches via the sphenoid sinus often require extended procedures, including concomitant posterior septectomy, removal of the intersinus septum, and drilling away a portion of the rostrum and inferior portion of the anterior sphenoid sinus wall.

Lavage of the Sphenoid Sinus

The least invasive procedure of the sphenoid sinus is a lavage of the sphenoid sinus (CPT#31002), in which the sphenoid sinus is accessed either via the natural opening or through the sphenoid sinus face. The sinus is irrigated with saline and aspirated. The contents can then be cultured or evaluated by a pathologist.

Nasal/Sinus Endoscopy, Diagnostic with Sphenoid Sinuscopy

A nasal/sinus endoscopy, diagnostic with sphenoid sinuscopy (CPT#31235) is a procedure in which a puncture is created or cannulation is performed of a nonsurgically opened ostium. The contents can then be irrigated, aspirated, cultured, or biopsied.

Nasal/Sinus Endoscopy, Surgical; With Dilation of Sphenoid Sinus Ostium

A nasal/sinus endoscopy with dilation of the sphenoid sinus ostium (CPT#31297) is procedure in which the sphenoid sinus ostium is dilated mechanically to allow improved drainage and access to the sphenoid sinus. The procedure can be performed in the office setting or the operating room. Topical anesthesia and decongestion is performed.

In an unoperated sinus, the natural ostium is typically identified medial to the superior turbinate. Depending on the style of catheter used, a probe or a wire is gently inserted into the ostium. Once the sinus is successfully cannulated, the dilation device or balloon is advanced into the sinus ostium. The balloon is then inflated to dilate the sinus ostium. The sinus contents may then be irrigated, aspirated, cultured, or biopsied.

Endoscopic Sphenoidotomy, Transnasal via the Natural Ostium

Endoscopic transnasal sphenoidotomy without ethmoidectomy via the natural ostium can be considered in cases of isolated sphenoid sinus disease.[4] This approach has the advantage of being minimally destructive of nasal mucosa and can result in shorter operative and recovery times; however, access to the sphenoidotomy site postoperatively may be limited because the ethmoid sinus cavity has not been opened.

A 30° nasal endoscope is often beneficial to provide visualization of the sphenoid sinus opening. Removal of part of the superior turbinate may be necessary to access the ostium and to facilitate postoperative care and inspection. The natural ostium of the sphenoid sinus usually lies just posterior to the superior turbinate. The anatomic landmarks that may be used to locate the natural ostium of the sphenoid sinus include the following:[9]

  • Posterior to the superior turbinate in the sphenoethmoid recess; the natural ostium is medial to the superior turbinate in 80% of cases

  • Approximately 6 cm from the nasal sill at an angle of 30° from the nasal cavity floor

  • Approximately 1 cm above the superior extend of the choana

  • At the approximate level of the maxillary sinus roof

Once the sphenoid ostium is identified, it is enlarged using a sphenoid sinus mushroom punch or a small Kerrison punch. The contents within the sphenoid sinus are then cultured, biopsied, irrigated, or removed. Care should be taken to avoid manipulation of the posterior wall of the sphenoid sinus, which could risk injury to the internal carotid artery, optic nerve, or skull base.

Endoscopic Sphenoidotomy, Transethmoidal via the Natural Ostium

Endoscopic transethmoidal sphenoidotomy is a sphenoidotomy performed through the passageway of an ethmoidectomy. This approach is the most commonly performed method, as it gives the widest view of the sphenoid sinus from lamina papyracea to rostrum. A total ethmoidectomy is first performed until the anterior face of the sphenoid sinus, skull base, and superior turbinate are identified. A decision can then be made to approach the sphenoid via the natural os or through a puncture into a thin section of bone of the anterior face of the sphenoid sinus. Although no comparison trials have evaluated these two methods, each has theoretical and anecdotal advantages and disadvantages.

Performing a sphenoidotomy via the natural os is theorized to limit postoperative recirculation of mucus and may be safer, as the sphenoid sinus is opened via a known opening in the sinus. In contrast, a sphenoidotomy via the anterior sinus wall avoids removing a potentially healthy superior turbinate and may lessen the risk of olfactory dysfunction. The comparative complication and patency rates between these two procedures are unknown.

A 0° nasal endoscope is typically used for the procedure. Angled endoscopes (30°, 45°, or 70°) are occasionally used to visualize the corners or floor of the large sphenoid sinus cavities once a sphenoidotomy has been performed. When identifying the natural ostium, the inferior one third to half of the superior turbinate is often resected using a straight thru-cutting forceps. It is not advisable to resect the superior turbinate too superiorly because of risks to olfactory dysfunction and skull base injury with cerebrospinal fluid leak. The natural ostium of the sphenoid sinus usually lies just posterior to the superior turbinate. The anatomic landmarks that may be used to locate the natural ostium of the sphenoid sinus include the following:[9]

  • Posterior to the superior turbinate in the sphenoethmoid recess; the natural ostium is medial to the superior turbinate in 80% of cases

  • Approximately 6 cm from the nasal sill at an angle of 30° from the nasal cavity floor

  • Approximately 1 cm above the superior extend of the choana

  • At the approximate level of the maxillary sinus roof

A J-curette or image guidance probe are helpful to bluntly palpate and identify the os when it cannot be visualized initially.[10] Once the natural os is identified, a straight mushroom punch, Kerrison punch, or other instrumentation may be used to enlarge the opening laterally and superiorly. The image below demonstrates an endoscopic transethmoidal sphenoidotomy performed via the natural ostium at 6 weeks postoperatively.

Left-sided sphenoidotomy site at 6 weeks postopera Left-sided sphenoidotomy site at 6 weeks postoperatively from removal of sphenoid sinus fungal ball.

Endoscopic Sphenoidotomy, Transethmoidal via Anterior Sinus Wall

Endoscopic transethmoidal sphenoidotomy via the anterior sinus wall avoids removing a potentially healthy superior turbinate and may lessen the risk of olfactory dysfunction.

A total ethmoidectomy is first performed until the anterior face of the sphenoid sinus, skull base, and superior turbinate are identified. A 0° nasal endoscope is typically used for this approach. Angled endoscopes (30°, 45°, or 70°) may be used to visualize the corners or the floor of the large sphenoid sinus cavities once a sphenoidotomy has been performed.

The superior turbinate is usually not resected unless the surgeon decides to incorporate the natural os. The image guidance system may be used to locate a safe location for entering the sinus. If no image guidance is available, the surgeon should choose a location that is somewhat inferior and medial with palpably evident thin bone to avoid skull base injury. A blunt sickle knife or J-curette is used to puncture through a thin section of bone in the anterior face of the sphenoid sinus. The sphenoid sinus mushroom punch, Kerrison punch, or other instrumentation can then be used to widen the sphenoidotomy.