Pneumosinus Dilatans of the Frontal Sinus: Diagnostic Workup and Management
Recommended Diagnostic Approach
In an otherwise healthy adult with pneumosinus dilatans of the frontal sinus, obtain high-resolution CT imaging without contrast to confirm the diagnosis and assess for complications, followed by surgical intervention if the patient has aesthetic concerns, functional symptoms (headache, sinus obstruction), or risk of complications.
Initial Imaging
High-resolution CT without contrast is the mandatory diagnostic study to confirm pneumosinus dilatans, showing abnormal expansion of the aerated frontal sinus with walls of normal thickness, distinguishing it from other pathology 1, 2.
CT imaging demonstrates the extent of bony expansion (generalized or focal), evaluates the anterior and posterior walls of the frontal sinus, and identifies any associated complications such as orbital or intracranial extension 1, 2, 3.
Coronal CT views are essential to assess the ostiomeatal complex, ethmoid involvement, and the relationship of the expanded sinus to critical structures including the orbit and skull base 1.
Additional Diagnostic Considerations
Nasal endoscopy should be performed to evaluate the frontal recess, assess for sinus ostium obstruction, and rule out concurrent sinonasal pathology such as polyps or mucosal disease 1.
MRI with contrast is reserved for cases where CT demonstrates skull base dehiscence, orbital extension, or when differentiation between retained secretions and soft tissue masses is needed 1.
The "ball valve" theory of mucosal obstruction at the frontal recess causing progressive expansion remains unproven, as patients with pneumosinus dilatans do not typically have retained secretions within the sinus and can tolerate pressure changes (such as diving) without symptom progression 4.
Optimal Management Strategy
Indications for Surgical Intervention
Surgery is indicated for: aesthetic deformity causing patient distress, functional symptoms (recurrent headaches, sinus obstruction), progressive expansion, or concern for complications 2, 3, 5.
Conservative observation is appropriate only for asymptomatic patients with stable, non-progressive disease who decline surgical intervention 2, 4.
Surgical Technique
The recommended surgical approach combines aesthetic reconstruction with functional sinus drainage:
Access via bicoronal incision provides optimal exposure of the frontal and supraorbital regions while hiding the scar in the hairline 2, 3, 6.
Remove the anterior wall of the affected frontal sinus, divide it into segments, and reposition/fixate the fragments using titanium mesh plates or miniplates to restore normal forehead contour 2, 3, 5.
Critically, widen the frontal sinus outflow tract during reconstruction to establish adequate drainage and prevent recurrence of sinus hypertrophy, particularly in patients presenting with headaches or obstructive symptoms 3.
Sinus obliteration with fat grafting after mucosal stripping may be performed in select cases, particularly when there is extensive ethmoid involvement or concern for recurrence 6.
Surgical Planning Considerations
Image-guided surgery is appropriate when there is concern about entering critical structures such as the orbit, skull base, or frontal recess during the procedure 7.
The extent of surgery should address both the cosmetic deformity and any functional obstruction, as constriction of the sinus ostium may contribute to cavity hypertrophy 3.
Asymmetric brow position resulting from unilateral frontal expansion may require concurrent brow lift procedures to achieve optimal aesthetic results 3.
Expected Outcomes and Follow-up
Excellent cosmetic results are typically achieved with no recurrence when adequate sinus drainage is established during reconstruction 2, 3, 5.
Major complications occur in less than 1% of cases when surgery is performed by experienced craniofacial surgeons 8.
Resolution of headaches and obstructive symptoms occurs when sinus outflow is adequately addressed during the procedure 3.
Long-term follow-up at 2 years demonstrates maintained aesthetic improvement and absence of recurrence when proper surgical technique is employed 2, 5.
Common Pitfalls to Avoid
Failing to address sinus drainage during aesthetic reconstruction leads to recurrent sinus hypertrophy and symptom persistence 3.
Performing simple anterior wall reduction without establishing adequate frontal recess patency results in continued obstruction and potential recurrence 3.
Delaying surgical intervention in symptomatic patients or those with progressive expansion increases the complexity of reconstruction and risk of complications 2, 6.
Misdiagnosing pneumosinus dilatans as other pathology (mucocele, tumor, fibrous dysplasia) due to inadequate imaging leads to inappropriate management 1, 2.