AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Acute ethmoid sinusitis can be bilateral or unilateral. It can have a bacterial, viral, or allergic etiology. When it is unresponsive to medical therapy, surgical intervention is often warranted. Ethmoid sinusitis that affects the anterior air cells can lead to dysfunction of the middle meatus. Because other sinuses, such as the maxillary and frontal sinuses, drain into this area, disruption in the mucociliary secretions passage in this area can obstruct those sinuses, also, leading to more fulminant disease.

History of the Procedure

Ethmoid sinusitis was often underappreciated for its role as a major causative factor in sinus disease. However, various authors had realized the contributing effect ethmoidal disease has upon sinus disease. As early as 1882, Zukerlandl had recommended that antrostomies should be made in the middle meatus to offset this problem.

Endoscopes were first used by Hirschmann in 1903, but instrumental events in our current understanding of sinus disease were the development of the rigid endoscope by H H Hopkins and its use in maxillary sinus surgery, reported in 1989 by Hopkins and Kapang. With the use of the endoscope, an understanding of mucociliary clearance patterns from the sinuses was obtained. The anatomy of the sinuses and the ostia were also better visualized with the endoscope, and the relationships between the intranasal and paranasal structures were better understood.¹

Problem

Acute ethmoid sinusitis denotes inflammation of the mucosal lining of the sinus.

Etiology

Ethmoiditis is often a sequela of an upper respiratory tract infection such as a cold. The impairment of drainage from the ostia of the sinus can also be caused by other factors, including polyps, foreign bodies, anatomical abnormalities (such as a deviated septum or an enlarged turbinate), or tumors. Immunocompromise, trauma, placement of feeding tubes, and abnormalities in cilia motility can put a patient at greater risk for developing sinusitis.²

Alternatively, dentition can also be a source of the infective material. Hematogenous spread is a much less common source.

Acute ethmoidal sinusitis is often bacterial in nature. Historically, Streptococcus pneumoniae and Haemophilus influenzae accounted for more than 50% of the pathogens in all types of acute sinusitis. Other pathogens include Staphylococcus aureus and Streptococcus pyogenes.² However, with the advent of the S pneumoniae and H influenzae vaccines, this predominance may change. In chronic sinusitis, anaerobes can be a factor, and, in immunocompromised patients, fungal pathogens and gram-negative bacilli can be causes of the sinusitis.

Acute ethmoid sinusitis is usually not abrupt in onset (except in cases caused by diving or swimming where bacterial organisms gain entry to the paranasal structures).³

Pathophysiology

The inflammation of the sinus mucosa from a common cold, for example, results in edema of the mucosa and can cause blockage of the natural ostia of the sinus leading to impairment of mucociliary drainage. The secretions accumulate within the sinus, and infection can set in. The ostiomeatal complex is intimately involved in the drainage of the ethmoidal sinuses.

Clinical

In general, patients with acute ethmoid sinusitis usually present with mild-to-moderate degrees of malaise. A discharge from the nares may be present, the nasal mucosa and turbinates may be edematous and hyperemic, and a purulent discharge may be present. Erythema of the nasopharynx and oropharynx can be present. Patients will often develop a low-grade fever and possibly a headache. The WBC count is usually not elevated unless a systemic cause for the sinusitis is involved. As the sinusitis progresses, pain usually increases over the ethmoidal area; however, the pain can be referred to the medial orbital and eye area and brow areas.

More severe cases of acute ethmoid sinusitis, especially in immunocompromised patients, can rapidly progress and present in an emergent way with facial cellulitis, orbital cellulitis, and meningitis.

INDICATIONS

Section 3 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

The typical case of acute ethmoidal sinusitis is treated with medical therapy. Medical treatment can reduce the inflammation and edema of the mucosa, alleviate the pain, combat the infection, open the ostia of the sinuses, and restore normal mucociliary secretions. However, surgery is indicated in the following instances:

• Sinusitis not responsive to medical management
• Rapidly progressing sinusitis
• Sinusitis that creates an abscess either in the sinus or adjacent areas such as the orbit or brain
• Sinusitis that compromises the survival of the patient

RELEVANT ANATOMY

Section 4 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

In infancy, the ethmoidal sinuses are developed, and they expand during early childhood.⁴ The sinuses are paired and are divided into anterior and posterior ethmoidal air cells. This division is provided by the basal lamella of the middle turbinate. In an adult, the average length of the sinus is 4-5 cm. The height is approximately 3 cm. The sinus widens from anterior to posterior, expanding from 0.5 cm anteriorly to 1.5 cm posteriorly.

The frontal, lacrimal, palatine, sphenoid, and maxillary bones contribute to the walls of the ethmoid sinus.⁵ Medially, the ethmoid sinus is demarcated by the lamina papyracea, which forms the medial wall of the orbit and the lateral nasal wall. Superiorly, it is demarcated by the fovea ethmoidalis.^{6, 7} The infundibulum of the ethmoid represents a cleft that is demarcated by the uncinate process on its medial side and the lamina papyracea on its lateral side.⁷ It connects the inferior aspect of the hiatus semilunaris with the superomedial aspect of the maxillary sinus.

The uncinate process is a bony curved prominence extending from the lateral nasal wall superiorly to the inferior turbinate. The ostiomeatal complex denotes the ultimate pathway for the secretions from the anterior ethmoidal air cells. Inferiorly, the hiatus semilunaris is the shortest distance from the free posterior margin of the uncinate process to the anterior aspect of the bulla ethmoidalis. Superiorly, it is a space between the lateral aspect of the middle turbinate and the superior aspect of the bulla ethmoidalis.⁷ The anterior air cells drain into the middle meatus, and the posterior air cells drain into the superior meatus.

CONTRAINDICATIONS

Section 5 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Surgical intervention for acute ethmoid sinusitis is contraindicated in poor surgical candidates who are unable to undergo the risks of anesthesia.

Most often the surgery is performed under general anesthesia. The desire to perform the surgery under local anesthesia with monitored anesthesia sedation must be carefully considered because hemorrhage in a partially sedated patient with no protection of the airway can be difficult to manage. However, the surgical method chosen, degree of surgery required, and experience of the surgeon are all qualifying factors.

Bleeding dyscrasias may also be a relative contraindication to surgery.

In 1994, Lawson stated that patients with a defect in the lamina papyracea, fovea ethmoidalis, or the cribriform plate should not have an ethmoidectomy from the intranasal approach.⁸ However, not all surgeons would agree.

WORKUP

Section 6 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Lab Studies

• As in all medical maladies, a thorough history and physical examination are required.
• Laboratory studies can include assessment for an elevated WBC count. However, this would be most useful for those patients with systemic findings.
• Cultures of the nasal passages may be helpful if culturable material is present. However, the pathogens found on the nasal mucosa may not be representative of the pathogens within the sinus.

Imaging Studies

• In the past, radiographs using both the Caldwell view to evaluate the ethmoid and frontal sinuses and the Waters view to evaluate the maxillary sinuses for concomitant involvement were often obtained in the evaluation of patients with acute ethmoid sinusitis.
• Computerized tomography (CT) of the paranasal sinuses and nose is the preferred method for imaging these structures because of its superior detail and clarity.

Diagnostic Procedures

• Nasal examination with a speculum is warranted to assess the intranasal structures. However, nasal endoscopy provides more detailed information and a more thorough examination than a nasal speculum examination.
• The typical nasal endoscopic examination is done in 3 passes, usually using a 0º  endoscope. Other endoscopes, such as 30º or 70º degree endoscopes, can also be used.
• • The first pass assesses the floor of the nasal cavity, the inferior turbinate, the septum, the inferior meatus, the eustachian orifice, the nasolacrimal duct opening, and the nasopharynx.
  • The second pass is directed toward the middle meatus between the middle and the inferior turbinate. This part of the examination evaluates the middle meatus, middle turbinate, uncinate process, bulla ethmoidalis, hiatus semilunaris, and the ostium of the maxillary sinus.
  • The third pass is accomplished by passing the endoscope upward directed toward the roof of the nasal cavity, between the upper part of the middle turbinate and the nasal septum, examining the frontal recess, the sphenoethmoidal recess, and ostium of the sphenoid sinus.
  • The condition of the nasal mucosa, discharge, anatomy, and other causes of obstruction such as abnormal turbinates, polyps, tumors, or foreign bodies can be searched for.^{2, 7}
  • Cultures can also be obtained.

TREATMENT

Section 7 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Medical therapy

Medical therapy for acute ethmoid sinusitis is geared toward eradicating the infection, opening the ostium, restoring the mucociliary function, and relief of pain.

Treatment is often empiric, with the use of antibacterial agents most often directed against gram-positive organisms. Antimicrobial agents such as ampicillin, amoxicillin, amoxicillin/clavulanate, erythromycin, clarithromycin, cefaclor, cefuroxime, and trimethoprim/sulfamethoxazole can be used, usually for 10 days. If dental extraction is implicated, consideration should be given to using metronidazole. Decongesting of the mucosa using topical oxymetazoline or oral decongestants can be helpful in shrinking the mucosa. Pain is managed as needed.

If the patient does not respond to treatment, the results of cultures can be used to guide further therapy. Investigations for atypical pathogens or immunocompromised status must be undertaken in an otherwise healthy patient who develops ethmoiditis that is not responsive to therapy and progresses. If Pseudomonas or fungal sinusitis may be present, it must be identified, and therapy must be altered to treat the offending agents.

Medical treatment may not be enough to resolve the ethmoiditis. In those cases that resolve but are not eradicated, chronic sinusitis may develop. Further antibiotic treatment and ultimately surgical therapy may be warranted for chronic ethmoidal sinusitis, but such matters are beyond the scope of this article.

When acute ethmoidal sinusitis is rapidly progressing, threatening to involve or involving contiguous areas such as the orbit, and not responding to aggressive antimicrobial therapy, surgical intervention is warranted. These patients are often hospitalized, and medical treatment consists of broad antibiotic coverage with more than one agent. In addition to the agents mentioned previously, these include ceftriaxone, vancomycin, ticarcillin/clavulanate, ampicillin/sulbactam, and ceftazidime. If improvement is not observed within 24 hours, surgical intervention is usually undertaken.

Surgical therapy

An ethmoidectomy is performed using one of 3 major approaches, the external ethmoidectomy, the intranasal (endoscopic) ethmoidectomy, and the transantral ethmoidectomy. Each approach offers advantages and has disadvantages. The ultimate decision of which approach to use will depend on the surgeon's preference and the extent of the disease. However, the transantral approach is the least used for isolated ethmoidal sinusitis. Depending on the extent of the disease, more than one approach may be combined during the surgical intervention.

External approach

This surgery can be performed under monitored anesthesia care or general anesthesia. General anesthesia may be preferred because manipulating the globe can be uncomfortable to the patient. An incision is made in a curvilinear fashion approximately 2.5-3 cm in length. It is positioned at the midpoint between the medial canthus and the middle of the anterior nasal bone. The skin is incised, and the dissection is carried down to the periosteum. If the angular artery is transected, it is cauterized or ligated. Dissection is carried subperiosteally to the posterior lacrimal crest, avoiding damage to the lacrimal excretory structures.

The medial canthal tendon may need to be released to allow for easier access to this area, and, if this is done, care must be taken to reposition it correctly. The posterior crest may need to be removed. Care must be taken not to extend the dissection superiorly to the frontoethmoidal suture as this demarcates the cranial fossa. The anterior ethmoidal artery lies at the level of this suture 20 mm posterior to the posterior lacrimal crest. The posterior ethmoidal artery is also at this level another 10 mm posterior, and the optic nerve is found 5 mm further back from the posterior ethmoidal artery. If needed, the anterior ethmoidal artery can be ligated.

The anterior cells are removed. The posterior cells can also be approached and treated as needed with ligation of the posterior ethmoidal artery if required. A drain is often placed and can be used in the postoperative period for lavage of the sinus. The medial canthal tendon is repositioned if needed, the periosteum can be closed or left open, and the skin is closed in layers.

Intranasal approach

This surgery can be performed with the patient under monitored anesthesia care or general anesthesia. Pledgets soaked in 4% cocaine or a combination of 4% lidocaine and 0.25% oxymetazoline are passed into the nasal cavity to anesthetize and decongest the mucosa. A local anesthetic containing 1% lidocaine and 1:100,000 epinephrine is injected into the mucosa of the middle turbinate, septum, and lateral wall. Hand instruments or powered instrumentation is used. If present, polyps are resected.

If the middle turbinate is obstructing the ostial area, such as with a concha bullosa, it can be partially resected. When manipulating the middle turbinate, care must be taken not to fracture the cribriform plate, which is just medial to the attachment of the turbinate, because this will cause a cerebrospinal fluid (CSF) leak.

The uncinate process and infundibulum are approached. An incision is made in the infundibulum and the uncinate process is resected. The mucosa can be incised with a sickle blade and removed with forceps. A loop curette or other noncutting instrument can be used to gently break into the anterior cells of the sinus. The cells are opened with biting instruments. Posteriorly, the dissection ends at the sphenoid sinus. Dissecting this far posterior in isolated anterior disease may not be necessary.

If the sphenoid sinus is involved, it must also be surgically addressed. The frontoethmoidal suture lies at approximately the level of the pupils, but this can be less reliable with a patient under general anesthesia. Complications from improper dissection of the sphenoid sinus can involve the optic nerve and carotid artery with disastrous consequences.

Culture can be obtained and material sent for pathologic examination as warranted. The nasal area is then packed with antibiotic ointment–coated gauze.

Transantral approach

This surgery can be performed under monitored anesthesia sedation or general anesthesia. A Caldwell-Luc approach is used. Once the maxillary sinus has been entered, the medial and superior walls of the maxillary sinus are identified. At the midpoint of the medial wall, the bulla ethmoidalis may be seen bulging into the maxillary sinus. A curette is used to enter this area, which is enlarged with a Kerrison rongeur or other bone cutting instruments. This allows access to most of the anterior cells, but the most anterior cells may be difficult to reach. The posterior cells off the ethmoid sinus can also be reached.

Preoperative details

CT scans should be obtained to determine the extent of the ethmoidectomy needed. The degree of surgery required is determined by the extent of the disease and not by a simple categorization or technique, such as limiting the surgery to only the anterior ethmoidal air cells as in the Messerklinger technique or a complete sphenoethmoidectomy as in the Wigand approach.⁶

Intraoperative details

Regardless of the approach used, the surgeon must be familiar with the anatomy and aware of all pertinent landmarks to reduce the risk of complications. Attention must be paid to avoid violating the cribriform plate or inadvertently entering the orbit. Avoiding injury to the septal mucosa, especially if the endoscopic approach is used, will diminish bleeding that otherwise would obscure the view. If bleeding is a problem it must be controlled, with cautery; thrombin; Gelfilm; Gelfoam; Surgicel; Merocel; or packing containing cocaine, adrenaline, phenylephrine, or oxymetazoline.

Postoperative details

The postoperative course and care of the patient will to some extent depend on the approach used. All patients are maintained on antibiotic therapy and pain medication. Culture results can be used to adjust the antimicrobial regime as needed. Once the prognosis is improved, steroid usage can be considered. Patients are instructed to avoid nose blowing for up to 1 week.

In the external approach, the drain is usually removed in 48-72 hours. It can also be used to lavage the sinus; however, the authors do not do this. The skin sutures are removed in approximately 7 days. Topical nasal decongestants are used for 3 days after surgery and then discontinued. The patient then uses nasal saline mist for 1 week.

In the endoscopic approach, the packing is removed within 48-72 hours. Topical nasal decongestants are used for 3 days after surgery and then discontinued. The patient then uses nasal saline mist for 1 week. Repeat nasal endoscopic examination and debridement in the postoperative period are usually necessary.

In the transantral approach, the patient rinses with an antiseptic mouthwash after each meal and at bedtime to maintain the hygiene of the mouth. The sutures are dissolvable. Topical nasal decongestants are used for 3 days after surgery and then discontinued. The patient then uses nasal saline mist for 1 week.

Follow-up

All patients have a follow-up visit the first day after surgery. Further follow-up visits are scheduled according to the surgical approach used and the degree of illness of the patient.

COMPLICATIONS

Section 8 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Complications of sinusitis

Ethmoidal sinusitis can spread outside of the borders of the sinus and cause an orbital cellulitis, orbital subperiosteal abscess, orbital abscess, superior orbital fissure syndrome, or cavernous sinus thrombosis. Cavernous sinus thrombosis can be life threatening and result in limited ocular motility, proptosis, and loss of vision. Intracranial complications are fortunately rare from sinusitis but can have a high morbidity and mortality and include meningitis, thrombophlebitis of the superior sagittal sinus, and abscess formation. Osteitis and osteomyelitis have also been observed. Mucoceles and pyoceles can occur.

Complications of ethmoid sinus surgery

Overall, the complication rate for ethmoid sinus surgery has been reported to be from 2-17%.²

The transantral approach does allow for access through the maxillary sinus and is a unilateral approach, but it provides restricted access to the most anterior ethmoidal air cells. In the transantral approach, damage to the dentition, oral-antral fistula formation, paresthesias in the distribution of the infraorbital nerve, and paresthesias in the gingivobuccal sulcus and alveolar ridge can also occur.

The external approach allows for visualization of the orbital contents and is a unilateral approach that will result in a cutaneous scar that could lead to medial canthal webbing, telecanthus, and medial canthal dystopia, especially if the medial canthal tendon is released and not properly repositioned. In the external approach, periorbital edema, injury to the extraocular muscles with diplopia, paresthesias in the distribution of the supraorbital, supratrochlear and infratrochlear nerve distributions, and blepharoptosis can also occur. The globe also can be injured. Blindness can occur from either a hematoma or excessive pressure on the globe occluding the central retinal artery during the surgery.

This endoscopic approach allows for access to both ethmoid sinuses, but it requires that the surgeon be facile with an endoscope. This approach can also cause an orbital hematoma and blindness. Diplopia can occur if an extraocular muscle, usually the medial rectus, is injured. Atrophic rhinitis has also been reported.⁹ More worrisome are the rare, but unfortunate, reports of blindness due to resecting the optic nerve. CSF leaks can also occur. Most will resolve with conservative treatment, but, if extensive and noted at the time of surgery, a leak should be addressed and repaired with dura, fat, mucosa, and/or fibrin glue. Synechia and ostial closure can also occur. Often, the synechia can occur between the turbinate and the septum. If it occurs between the turbinate and the lateral wall, blockage of the ostium can occur.¹⁰

OUTCOME AND PROGNOSIS

Section 9 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Most patients who undergo ethmoidectomy for acute ethmoid sinusitis obtain resolution of the disease. However, chronic sinusitis and other problems can occur. Improvement following ethmoidectomy has ranged from 46-98%.¹ The success rate for the external approach ranged from 70-93% and for the endoscopic approach from 46-98%.

FUTURE AND CONTROVERSIES

Section 10 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

The use of image guidance systems that correlate the intraoperative position of the instrumentation with the CT scan anatomy may reduce complications in adjacent structures during the more posterior dissection. Improved antibiotic penetration of the sinuses may reduce the need for surgical intervention.

MULTIMEDIA

Section 11 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

Media file 1:  Ethmoid sinusitis, surgical treatment. Mild ethmoid sinusitis.
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Media type:  CT

Media file 2:  Ethmoid sinusitis, surgical treatment. Ethmoid opacification in conjunction with opacification of the ethmoid sinus in a patient with orbital fractures.
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Media type:  CT

REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome And Prognosis
• Future And Controversies
• Multimedia
• References

1. Jones N. Endoscopic sinus surgery. In: Jones AS, Phillips DE, Hilgers FJ, eds. Diseases of the Head and Neck, Nose and Throat. 1st ed. Arnold Edward;1998:846-867.
2. Feldman BA, Feldman DA. The nose and sinuses. In: Essential Otolaryngology: Head and Neck Surgery. 5th ed. Appleton & Lange;1991:669-81.
3. Schuller DE, Schleuning AJ. Clinical problems. In: DeWeese and Saunder's Otolaryngology: Head and Neck Surgery. 8th ed. 1997:89-133.
4. Wolf G, Anderhuber W, Kuhn F. Development of the paranasal sinuses in children: implications for paranasal sinus surgery. Ann Otol Rhinol Laryngol. Sep 1993;102(9):705-11. [Medline].
5. Gardner E, Gray DJ, O'Rahilly RO. Nose and paranasal sinuses. In: Anatomy: A Regional Study of Human Structure. 4th ed. WB Saunders Co;1975:732-41.
6. Swift AC. Complications of sinusitis. In: Jones AS, Phillips DE, Hilgers FJ, eds. Diseases of the Head and Neck, Nose and Throat. 1st ed. Arnold Edward;1998:868-83.
7. Yanagisawa E. Endoscopic anatomy of the lateral nasal wall and the paranasal sinuses. In: Krouse JH, Christmas DA, eds. Powered Endoscopic Sinus Surgery. 1997:7-26.
8. Lawson W. The intranasal ethmoidectomy: evolution and an assessment of the procedure. Laryngoscope. Jun 1994;104(6 Pt 2):1-49. [Medline].
9. Miller RH, Cote DN. Open operation for paranasal sinusitis. In: Ballenger JJ, Snow JB Jr, eds. Otorhinolaryngology: Head and Neck Surgery. 15th ed. Lippincott Williams & Wilkins;1996:185-9.
10. Templer J. Ethmoidectomy. In: English GH, ed. Otolaryngology. Vol 2. 1997:1-8.
11. Aral M, Keles E, Kaygusuz I. The microbiology of ethmoid and maxillary sinuses in patients with chronicsinusitis. Am J Otolaryngol. May-Jun 2003;24(3):163-8. [Medline].
12. Ben Simon GJ, Bush S, Selva D, McNab AA. Orbital cellulitis: a rare complication after orbital blowout fracture. Ophthalmology. Nov 2005;112(11):2030-4. [Medline].
13. Brook I. Bacteriology of acute and chronic ethmoid sinusitis. J Clin Microbiol. Jul 2005;43(7):3479-80. [Medline].
14. Hirschmann A. Uber Endoskopie der Nase und deren Nebenholhen. Arch Otorhinolaryngol (Berlin). 1903;14:194-8.
15. Hosemann W, Wigand ME, Nikol J. [Clinical and functional aspects of endonasal operation of the maxillary sinuses]. HNO. Jun 1989;37(6):225-30. [Medline].
16. Zukerlandl E. Normal und Pathologische Anatomie der Nasenhle und Iher Pneumatischen Anhänge. Wein Braümuller.

Article Last Updated: Aug 14, 2007