What is the maxillary antrostomy procedure?

Maxillary Antrostomy Procedure Explanation

A maxillary antrostomy is a surgical procedure that creates an opening in the lateral nasal wall to access the maxillary sinus, typically performed to improve drainage and ventilation in patients with chronic maxillary sinusitis that has failed medical therapy. 1

Procedure Types and Techniques

Standard Middle Meatal Antrostomy

• Involves creating an opening in the middle meatus by removing the uncinate process and enlarging the natural ostium of the maxillary sinus 1
• Typically performed endoscopically as part of functional endoscopic sinus surgery (FESS) 2
• Size of the antrostomy varies based on disease severity and surgeon preference, but generally ranges from 3-4 mm to larger openings 1

Simplified Antrostomy Design

• Three-step procedure that begins with measurements from cone beam CT to open a small window (3 mm wide by 6 mm long) just distal to the anterior sinus wall 1
• The window is then extended anteriorly (mesially) to locate the anterior sinus wall 1
• Finally, the antrostomy is enlarged distally based on internal anatomy and implant needs, typically 15-20 mm in the anteroposterior direction 1

Low Window Antrostomy Design

• A modification of the simplified design where the window is placed as low and mesially as possible 1
• The lower osteotomy line is placed flush with the sinus floor, eliminating residual bone wall that could hinder membrane detachment 1
• Window height is usually 6-8 mm, which helps avoid intraosseous anastomosis 1

Endoscopic Maxillary Mega-Antrostomy (EMMA)

• Used for recalcitrant maxillary sinusitis that hasn't responded to standard antrostomy 3
• Involves extending the antrostomy through the posterior half of the inferior turbinate down to the floor of the nose 3
• Creates a significantly enlarged opening for better drainage and access 3

Visualization Techniques

• Initial antrostomy is typically performed using a 0° endoscope 2
• A 70° endoscope is often needed to fully visualize the anterior maxillary sinus and ensure complete dissection 2
• Studies show that in 82.9% of cases, residual inflammatory tissue in the anterior maxillary sinus was found when switching from 0° to 70° endoscopes 2

Historical Context

• Before endoscopic techniques, the Caldwell-Luc procedure was the standard operation 1
• This involved an inferior meatal antrostomy and maxillotomy after an incision above the canine fossa 1
• The procedure had longer hospitalization time and recovery compared to current endoscopic approaches 1
• Caldwell-Luc procedures are rarely performed now except for cases of malignant disease 1

Potential Complications and Management

• Synechiae (bridging scar formation) can occur between the middle turbinate and lateral nasal wall or septum 1
• Membrane perforation during antrostomy preparation can be prevented with proper preoperative 3D evaluation 1
• Improper location of the antrostomy (too superior or distal) is a common error among less experienced surgeons 1
• Retained secretions in the maxillary sinus may occur despite surgical enlargement of the ostia 1

Post-Procedure Considerations

• Assessment of the patency of the surgically created ostium is important during follow-up 1
• Postoperative narrowing can result from synechiae, edema, thickened mucus, fungus balls, or polyps 1
• Nasal saline irrigations are recommended after the procedure to improve mucociliary clearance 4
• Continued medical therapy to maintain sinus patency is necessary after the procedure 4

Effectiveness

• Endoscopic maxillary antrostomy is effective for improving chronic maxillary sinusitis symptoms 5
• For recalcitrant cases, the mega-antrostomy approach has shown complete resolution of symptoms in 74% of patients and partial improvement in 26% 3
• Studies comparing middle and inferior meatal antrostomies have shown no significant difference in outcomes 6