Overview
When an acute inflammatory response occurs in the sphenoid sinus, the result is sphenoid sinusitis, or sphenoiditis. The disease is relatively uncommon—comparatively, chronic sphenoid sinusitis is more common—and may be limited to the sphenoid sinus or, more commonly, may involve multiple sinuses or pansinusitis. Early diagnosis and treatment are essential, because the disease can be rapidly progressive and complications arising from the relationship of the sphenoid sinus to vital vascular, neurologic, and optic structures can be devastating.
In a study of 136 patients with acute isolated sphenoid sinusitis, Farhat et al reported that 98% presented with headache, most commonly retro-orbital, vertex, and frontal headaches. Nasal obstruction, postnasal drip, and fever were encountered in 24%, 10%, and 9% of patients, respectively. The investigators also reported that the symptoms of acute isolated sphenoid sinusitis show no relationship to the diagnostic criteria for acute sinusitis presented in the European Position Paper on Rhinosinusitis and Nasal Polyps 2020 (EPOS 2020). [1, 2]
A retrospective study by Shpilberg et al found that extension of the sphenoid sinuses into the posterior nasal septum is among the most common normal variants seen on computed tomography (CT) scans of the sinuses. However, no significant association was found to exist between the presence of this or other common normal variants (nasal septal deviation, Agger nasi cells) and the development of rhinosinusitis. The investigators reviewed 192 sinus CT scan examinations from patients with a clinical history of rhinosinusitis, comparing sinonasal variants in patients with imaging evidence of clinically significant rhinosinusitis with those of patients with little or no such evidence. [3]
In a literature review of pediatric patients with isolated acute sphenoid sinusitis, Clement et al found the most common presenting symptoms to be headache (98.6%), fever (50.7%), nasal symptoms (22.5%), ocular symptoms (19.7%), and decreased consciousness level (12.7%). [4]
Treatment Considerations
Some authors advocate early and aggressive surgical and medical treatment for acute sphenoid sinusitis. Hnatuk commented on the aggressive nature of the disease and concluded that nonoperative medical management is not indicated. [5] However, these conclusions were based on a small number of patients, all in their teenage years.
In general, start medical treatment of uncomplicated acute sphenoid sinusitis once the diagnosis is made with the administration of broad-spectrum antibiotics, as well as the addition of topical and systemic decongestants. Try medical treatment for 24 hours. If the patient does not improve over this time course, schedule surgical therapy; if the patient has evidence of complications, undertake urgent surgical decompression.
Sethi described an interesting modification of this algorithm, [6] in which daily endoscopic decongestion and assessment of the sphenoethmoidal recess was performed, allowing direct evaluation of the relevant anatomy. Three of the 8 patients in this study did well with this regimen, whereas 5 patients did not improve and required surgery.
In the aforementioned literature review by Clement et al, of children with isolated acute sphenoid sinusitis, the investigators reported that sinus surgery, revision sinus surgery, and neurosurgery were performed in 31.0%, 2.8%, and 2.8% of patients, respectively, with antibiotic therapy administered to 98.6% of individuals. [4]
Surgical Considerations
Surgery is reserved for unresponsive disease and impending complications. The goals of surgery are to identify the sphenoid ostium, enlarge it, establish drainage, and obtain material for culture. Diseased mucosa should be removed and cultures should be obtained. Many surgical approaches have been described. The classic approaches include transseptal, transantral, intranasal, and external, but endoscopic surgery for sphenoidectomy is now commonly used.
Open approaches, including an external ethmoidectomy or transseptal approach, can also be used. The outcome of sphenoid sinusitis is highly dependent on the speed of diagnosis.
Image guidance systems are being used more frequently in sinus surgery. The use of these in diseases of the sphenoid is especially helpful and adds an extra dimension of safety to the surgery. A study by Jiang and Liang found that in patients with chronic rhinosinusitis undergoing revision functional endoscopic sinus surgery to open the sphenoid sinus, the rate of sphenoid sinus penetration was higher in those who underwent image-guided surgery than in patients whose surgery was not image guided. The study, in which image-guided and non-imaged-guided surgery was performed in 51 and 30 patients, respectively, reported a 91% sphenoid sinus penetration rate in the image-guided group, compared with an approximately 69% penetration rate in the other group. [7]
Very few contraindications to urgent surgical decompression of the sphenoid sinus exist if a patient is having complications or is unresponsive to medical management. Unstable vital signs or excessive bleeding might require waiting until these problems can be temporized. Chronic medical conditions might preclude general anesthesia. If the sphenoid sinus is the underlying problem, however, decompression is beneficial.
Preoperative Assessment
Preoperatively, review the imaging studies to determine the bony anatomy and areas of disease. Decide the approach to the sphenoid sinus based on any associated disease, as well as surgeon preference.
Surgical Approaches
When operating on the sphenoid sinus, be aware of the relationship of the sphenoid to the surrounding structures. The anterior wall of the sphenoid is approximately 7 cm from the anterior nasal spine and 30° off the nasal floor. The distance to the posterior sphenoid wall is approximated by measuring the distance to the posterior nasopharynx, which is about 9 cm.
The carotid artery and optic nerve may be observed indenting the lateral walls of the sphenoid sinus. The carotid artery is dehiscent in 4% of patients and covered with only a thin bony covering in 71% of patients. The optic nerve is found in the superolateral aspect of the sinus, also dehiscent in 4% of patients. A margin of safety can be obtained by staying medial and inferior when opening and exploring the sphenoid.
Transseptal transsphenoidal approach
Many approaches to the sphenoid have been described. Among the earliest was the transseptal transsphenoidal approach, described by Cushing and Hirsh in 1910 in the context of pituitary tumor resection. [8] This approach was re popularized by Hardy in the 1950s and is still in use today.
The transseptal approaches can be via sublabial incision, external rhinoplasty incision, or alar incision. The sublabial incision is most common because of the relative ease of the procedure, its midline exposure, and the lack of external scar. However, oral contamination is a disadvantage.
For the sublabial approach, inject lidocaine with epinephrine into the upper buccal sulcus, septum, and floor of the nose. Make an incision in the upper sulcus and carry the incision down to the bone. Elevate the periosteum to the piriform aperture laterally, and elevate the anterior nasal spine medially. Elevate a mucoperichondrial flap on one side of the septum and the nasal floor bilaterally, leaving the contralateral septal mucosa intact.
Disarticulate the septum at the bony-cartilaginous junction, and remove the perpendicular plate to expose the sphenoid rostrum. Following placement of a pituitary speculum, fluoroscopy can be used if needed to confirm placement. Enter the sphenoid sinus in the midline with an operating microscope.
Transantral approach
The transantral approach has also been used for sphenoid disease. For this approach, make a sublabial canine fossa incision. Open the anterior maxillary sinus wall and address any antral disease. Remove the nasoantral wall, exposing the middle turbinate. Use the middle turbinate as a guide to the sphenoid ostium, which is found superior and medial to the posterior aspect of the middle turbinate. Then, open the anterior sphenoid wall.
Intranasal approach
Another classic approach is the intranasal approach. Perform typical nasal decongestion; then, fracture the middle turbinate medially. Perform an ethmoidectomy, followed by lateralization of the posterior attachment of the middle turbinate. Identify the sphenoid ostium medially to the middle turbinate, enter it, and enlarge it toward the midline. Remove the posterior ethmoid cells to create a common cavity between the sphenoid sinus and the posterior ethmoid. External sphenoethmoidectomy is used infrequently, because an external incision is needed.
Endoscopic approach
The advent of endoscopic sinus surgery has dramatically changed the approach to sphenoid disease. Endoscopic approaches provide excellent visualization of the anatomy and disease process. Advantages include reduced operating time, minimal blood loss, and decreased morbidity, compared with classic techniques. Metson commented on the widespread popularity of endoscopy and evaluated the efficacy of the endoscopic approach, deeming it effective and safe in the treatment of sphenoid sinusitis. [9, 10, 11]
A study by Chowdhury et al indicated that in patients who undergo endoscopic sinus surgery, baseline scores on the Short Form-8 (SF-8) Health Survey with regard to pain and role limitations due to physical health, as well as the patient’s smoking status, independently predict pain scores on the third postoperative day. [12]
Although rarely used in acute sinusitis, Zhao et al reported success with balloon catheter dilation of the sinus ostia in the treatment of a girl aged 5 years with acute left sphenoid sinusitis and associated left-sided vision impairment. [13]
A randomized, controlled study by Sikand et al reported that at 24-week follow-up, adults diagnosed with recurrent acute rhinosinusitis who were treated with a combination of balloon sinus dilation and medical management experienced significantly greater improvement in quality of life than did those who underwent medical management alone, as evaluated using the Chronic Sinusitis Survey. [14]
Transethmoidal approach
If sinus disease involves both the sphenoid and the ethmoid sinuses, a transethmoidal approach is taken. Medialize the middle turbinate to visualize the uncinate process. Remove the uncinate, and identify and open the ethmoid bulla. Then, perform an anterior and posterior ethmoidectomy. The sphenoid sinus is located medial and inferior to the posterior ethmoid air cells. Use a probe to approximate the anterior wall of the sphenoid at 7 cm from the nasal spine and 30° off the nasal floor. Enlarge the opening while taking care to stay medial and inferior in order to avoid the vital structures. The distance to the posterior nasopharyngeal wall approximates the posterior wall of the sinus and usually measures 9 cm.
Transnasal approach
If isolated sphenoid disease is present, a transnasal approach can be used. Displace the middle turbinate laterally, and pass the endoscope along the septum until the superior turbinate is identified. Transect and remove the superior aspect of the superior turbinate. Identify the sphenoid ostium in the area between the remnant and the septum. Inferiorly enlarge the ostium. An endoscope can then be passed directly into the sphenoid sinus to evaluate the location of the carotid artery and optic nerve. With these structures identified, the ostium can be enlarged further. A diameter of 5-10 mm is advocated to reduce the likelihood of recurrent obstruction.
Alternate approach to isolated sphenoid disease
Stankiewicz described an alternate approach to isolated sphenoid disease, advocating fracturing the middle turbinate toward the septum. [15] Make incisions in the anterior superior and posterior inferior portion of the middle turbinate and remove this tissue. The basal lamella remains intact as a landmark. With a probe, measure the distance to the sphenoid ostium; then, enter the sphenoid.
Monitoring
Postoperatively, continue administration of broad-spectrum antibiotics. Adjust the antibiotic choices when culture results are available. Closely monitor the patient for complications of the sinus disease as well as the procedure.
Acute sphenoid sinusitis should respond to medical and surgical management as described above. Monitor patients who develop complications of sphenoid sinusitis for progression or resolution of their symptoms. Patients who develop repeated episodes of sphenoid sinusitis may have an anatomic predisposition, such as a narrowed ostium, and may require surgery. Chronic sphenoid sinusitis is a different entity and may respond to medical or surgical treatment. In contrast to acute sphenoiditis, chronic disease is not considered a medical emergency.
Surgical Complications
Intraoperative complications
The sinus surgery itself has potential complications, again based on the vital structures that surround the sphenoid sinus. Intraoperative complications are predominantly vascular in nature and include persistent hemorrhage from the carotid artery or, infrequently, the cavernous sinus. Retrobulbar hemorrhage with proptosis and visual compromise requires urgent ophthalmologic consultation and lateral canthotomy. Persistent hemorrhage from the sphenoid or cavernous sinus may require angiography to localize and control bleeding.
Postoperative complications
Postoperative complications may be nasal, neurologic, or vascular in nature. Long-term complications include cosmetic deformities. Septal perforations may occur and are predominantly related to approach. In the perioperative state, epistaxis is also a risk. Neural structures, including the optic nerve or any structures running through the cavernous sinus, may be damaged during surgery.
Cranial nerves (CNs) that control extraocular movements (CNs III, IV, VI) are at risk, as are the ophthalmic (V1) and maxillary (V2) branches of CN V. Cerebrospinal fluid leak is possible if the roof of the sphenoid is violated. Hemorrhage from the internal carotid artery or cavernous sinus is a devastating complication that may occur intraoperatively or postoperatively. Immediately evaluate any unexplained mental status changes or excessive bleeding.
