What is a Functional Endoscopic Sinus Surgery (FESS) procedure with imaging guidance, particularly in pediatric patients?

What is a FESS Procedure with Imaging Guidance?

Functional Endoscopic Sinus Surgery (FESS) with imaging guidance is a minimally invasive surgical technique that uses endoscopes, video systems, and real-time CT-based computer navigation to access and treat diseased paranasal sinuses without external incisions, primarily indicated for chronic rhinosinusitis refractory to medical management. 1

Core Surgical Technique

FESS is performed using:

• A telescope and video system that allows direct visualization of the nasal cavity and sinuses through the nostrils 1
• Specialized instruments to remove diseased tissue and open blocked sinus drainage pathways 1
• No external incisions, distinguishing it from traditional open sinus procedures 1, 2

The fundamental principle is that most chronic sinus disease originates from obstruction in the anterior ethmoid cells and ostiomeatal complex (the critical drainage area in the middle meatus), so surgery targets these specific anatomical regions rather than stripping all sinus mucosa 1, 2

Imaging Guidance Component

Preoperative CT Planning

The surgeon must obtain a CT scan with fine-cut protocol before surgery to examine the paranasal sinuses for surgical planning. 1 This imaging:

• Delineates the extent of disease in three-dimensional views (axial, coronal, sagittal) 1
• Identifies anatomical variants and erosive or osteitic processes 1
• Forms the basis for informed preoperative and intraoperative decisions 1
• Requires thinner cuts for higher resolution, with specific protocols needed if intraoperative image guidance is planned 1

Intraoperative Computer-Aided Navigation

Image-guided FESS integrates real-time computer navigation (such as the StealthStation system) that:

• Provides localization accuracy within 2 mm or better during surgery 3
• Uses anatomic fiducial registration supplemented by contour mapping 3
• Is particularly useful in the frontal recess, sphenoethmoid region, posterior ethmoid system, and skull base area 3
• Is especially helpful when surgical anatomy is altered by previous surgery or extensive inflammatory disease (polyposis, fungal sinusitis, pansinusitis) 3

The American College of Radiology states that image-guided surgery is appropriate when there is concern about entering critical structures such as the orbit, skull base, or frontal recess 4

Primary Indications

FESS is indicated for:

• Chronic rhinosinusitis refractory to appropriate medical management (at least 4 weeks of intranasal corticosteroids, saline irrigations, and other medical therapy) 1, 4
• Nasal polyposis 1, 5
• Recurrent acute sinusitis 6
• Fungal sinusitis 5, 3
• Anatomical obstruction of the ostiomeatal complex 1

The surgeon should not plan surgery solely based on arbitrary CT criteria regarding minimal mucosal thickening or sinus opacification, but rather on the combination of symptoms and objective findings. 1

Surgical Goals and Extent

The goals of FESS include:

• Improving natural drainage of the paranasal sinuses 1
• Excising diseased tissue while preserving normal mucosa 1
• Creating ventilation pathways for mucociliary clearance 1

When sinuses involve polyps, osteitis, bony erosion, or fungal disease, the surgeon should perform surgery that includes full exposure of the sinus cavity and removal of diseased tissue, not just balloon or manual ostial dilation. 1

The extent of surgical dissection is dictated by the amount and location of disease identified on preoperative CT and intraoperative findings, with surgery extending beyond the margins of ostiomeatal disease 1

Outcomes and Safety

• Improvement rates of approximately 80-88% in both adult and pediatric patients 6, 7
• Major complication rate of approximately 0.5%, though meticulous surgical techniques require considerable experience 1, 7
• Minor complications occur in approximately 8% of patients 7
• Postoperative pain is typically minimal with early symptom improvement 1

Critical Postoperative Management

The surgeon must routinely follow up between 3 and 12 months after surgery to assess outcomes through history (symptom relief, quality of life, complications) and nasal endoscopy. 1 This is essential because:

• FESS is often best understood as a component of an overall management strategy rather than a sole curative intervention 1
• Postoperative use of topical corticosteroids, saline irrigation, and management of atopic disease are often necessary to maintain surgical results 1
• Endoscopic debridement may be needed to remove retained secretions, crusting, and packing material that can impair healing 8

Common Pitfalls to Avoid

• Do not proceed with FESS without documented failure of at least 4 weeks of appropriate medical management including intranasal corticosteroids and saline irrigations 4
• Do not plan surgery based solely on CT findings without correlating symptoms - neither symptoms alone nor CT findings alone are sufficient to establish the diagnosis of chronic rhinosinusitis 1
• Do not assume all patients are cured after surgery - approximately 41.5% still require some ongoing medical therapy postoperatively 7
• Recognize that relapses after surgery are not infrequent and are usually best managed medically if the initial surgery was technically adequate 1