Maxillary Antrostomy Sinus Surgery

Maxillary antrostomy is a surgical procedure to enlarge the opening (ostium) of the maxillary sinus. This allows for further surgical intervention within the maxillary sinus cavity as well as improved sinus drainage. Maxillary antrostomy has been practiced since the mid-1980s and is the most likely surgical approach to be performed if you have chronic sinusitis that is unresponsive to other medical therapies. In this case, the procedure is part of the endoscopic sinus surgery which may be your next best option. Standard medical therapies include an antibiotic trial (3-6 weeks), nasal steroids, and saline irrigations.

Note: This procedure is different than balloon sinuplasty of the maxillary sinus ostium which is a very commonly performed procedure now and may be preferable to an antrostomy.

Also known as: endoscopic middle meatal maxillary antrostomy, middle meatal antrostomy

A man looking at his sinusitis
BSIP / Getty Images

Diagnosing Chronic Sinusitis

Prior to undergoing sinus surgery, your healthcare provider will want to confirm chronic sinusitis with a CT scan. X-rays are not as often desired, as they can only show sinus disease and less specific information regarding other nasal sinus issues. The CT scan not only will show the severity of maxillary sinus inflammation but will also provide your healthcare provider with this other important information:

  • Position of the nasolacrimal duct
  • Uncinate process — which is an important part of the surgical process
  • Thickening of the mucus membranes
  • Air versus fluid levels in the sinus cavities
  • Polyps
  • Osteomeatal complex obstruction — prevents drainage of the maxillary sinus

While this is a lot of technical medical terminology, all this information will provide your healthcare provider with the information needed to be properly prepared for your surgical procedure. The osteomeatal complex is made up of the following four nasal structures:

  • Uncinate process — is an L-shaped bone that will be removed
  • maxillary ostium (opening of the maxillary sinus)
  • infundibulum — curved channel in the nose
  • ethmoid bulla — one of the ethmoid sinuses

Preparation for Endoscopic Sinus Surgery and Maxillary Antrostomy

Prior to surgery, you will have been instructed to have nothing to eat or drink from midnight the day of surgery until after the surgery is performed. This will help prevent your risk of inhaling stomach contents (aspiration). In the pre op area, you will most likely be given Afrin nasal spray to decongest your nasal passages to help increase the area of visibility during your surgery. Once anesthetized, you may also have gauze soaked in Afrin or topical cocaine used in your nose to further enhance visibility if necessary.


There are 3 main goals that your healthcare provider will try to accomplish during a maxillary Antrostomy

  1. Remove the uncinate process
  2. Finding the natural opening into the maxillary sinus
  3. Enlarging the opening into the maxillary sinus
  4. Remove polyps from within the maxillary sinus cavity

It is important that your healthcare provider remove the uncinate process at the beginning of the procedure in order to better visualize the maxillary sinus opening. If the sinus opening is not located and a new opening is created, you can have recycling of sinus drainage, where drainage exits one opening and reenters the sinus cavity through the other opening.

After a Maxillary Antrostomy

After your surgery is complete, you will wake up in the post-anesthesia care unit (PACU). There you will be monitored for bleeding, nausea (which can occur if blood is swallowed), or other potential complications from the surgery. You will then follow-up with your healthcare provider between 3 and 5 days to have your nasal packing removed. Depending on the success and if you have any remaining symptoms will determine what further medical interventions are tried after surgery.


Aside from normal risks associated with any surgery requiring general anesthesia, maxillary antrostomy also has the following risk factors:

Aside from a nosebleed, most of the previously listed risk factors are quite rare. Maxillary antrostomy is a common procedure, however, these are the associated risk factors. Many of these factors are in relation to surgical instruments used like the microdebrider, which is also generally safe and has relatively few complications. However the risk factors listed above are severe albeit rare, so please always choose a skilled ENT to perform the procedure.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Novis SJ, Akkina SR, Lynn S, Kern HE, Keshavarzi NR, Pynnonen MA. A diagnostic dilemma: chronic sinusitis diagnosed by non-otolaryngologistsInt Forum Allergy Rhinol. 2016;6(5):486–490. doi:10.1002/alr.21691

  2. Weber RK, Hosemann W. Comprehensive review on endonasal endoscopic sinus surgeryGMS Curr Top Otorhinolaryngol Head Neck Surg. 2015;14:Doc08. doi:10.3205/cto000123

  3. Myller JP, Luukkainen AT, Huhtala HS, Torkkeli TV, Rautiainen ME, Toppila-Salmi SK. Satisfaction with maxillary sinus surgery might be influenced by risk factorsAllergy Rhinol (Providence). 2013;4(1):e6–e12. doi:10.2500/ar.2013.4.0039

Additional Reading

By Kristin Hayes, RN
Kristin Hayes, RN, is a registered nurse specializing in ear, nose, and throat disorders for both adults and children.