Graded Approach for Frontal Sinus Disease

Graduated Approach - Summary Table (Scott-Brown's TABLE 99.3)

Draf Classification - Detail (Cummings / Scott-Brown's)

Draf Type I

• Complete anterior ethmoidectomy with removal of the bulla, suprabullar cells, agger nasi, and uncinate process
• Does not violate the mucosa of the frontal recess - most of the time, this is sufficient to drain the frontal sinus
• Best limited to cases with only minor frontal sinus pathology
• May not suffice in significant nasal polyposis with aspirin intolerance and asthma

Draf Type IIa ("Uncapping the Egg" / Frontal Sinusotomy)

• Enlargement of the frontal outflow tract; removes all occupying cells (agger nasi, frontoethmoidal cells) without damaging the mucosa of the frontal recess
• Widens the frontal recess from the lamina papyracea to the middle turbinate medially
• Mucosa should be preserved circumferentially; if not fully possible, at least >50% should be preserved
• May not be ideal for CRS with nasal polyps (CRSwNP), especially when polyps are present in the frontal sinus itself - higher postoperative opacification rates

Draf Type IIb (Unilateral Frontal Sinus Drillout)

• Enlarges the frontal ostium by drilling the floor of the frontal sinus from the lamina papyracea to the nasal septum (removes the anterior middle turbinate attachment)
• Produces the maximum possible unilateral outflow tract
• High risk of stenosis due to mucosal damage by the drill - seldom used for CRS
• Specific indications: unilateral frontal ostium osteoneogenesis, inverted papilloma, osteomas, medially placed frontal mucoceles, or when a mucocele has already "auto-performed" most of the dissection

Draf Type III (Modified Endoscopic Lothrop Procedure / Bilateral Frontal Drillout)

• Complete drillout of the floor of both frontal sinuses, intersinus septum, frontal beak, and superoanterior nasal septum - creating one large common frontal sinus cavity (orbit-to-orbit)
• Synonyms: endoscopic modified Lothrop, median drainage procedure, bilateral frontal sinus drillout
• Technically demanding - useful landmarks are often absent and the operative field is narrow
• Mini trephine and computer-assisted navigation help with identification of the frontal ostium
• The "frontal T" landmark (first olfactory neurones at the posterior margin) helps define safe limits

• Chronic frontal sinusitis refractory to previous endoscopic surgery
• CRS with nasal polyps + asthma + aspirin-exacerbated respiratory disease (controversial; may be primary)
• Allergic fungal sinusitis / eosinophilic mucin CRS
• Large frontal mucoceles (even beyond the mid-pupillary line)
• Salvage after failed osteoplastic flap obliteration
• Frontal osteoma (grade I and II; less suitable for grade III/IV)
• Inverted papilloma extending into the frontal sinus

Important "All or None" principle (Cummings): Drilling in the frontal recess causes unavoidable mucosal damage and significant stenosis risk. Therefore, if a drill is used in the frontal recess, one should generally proceed to a complete Draf III rather than stopping at IIb - unless tissue quality is good (e.g., benign tumors, mucocele).

International Classification of Extent of Frontal Sinus Surgery (EFSS)

• Grade 0 - Balloon sinus dilation without tissue removal
• Grade 1 - Removal of cells in the frontal recess not obstructing the ostium
• Grade 2 - Removal of cells directly obstructing the ostium
• Grade 3 - Removal of cells pneumatizing through the frontal ostium into the frontal sinus, without enlargement of the ostium

• Grade 4 - Removal of cells pneumatizing through the ostium with enlargement of the ostium itself
• Grade 5 - Ostium enlargement from the lamina papyracea to the nasal septum (= Draf IIb)
• Grade 6 - Resection of the floor of the frontal sinus creating a common ostium between right and left (= Draf III)

Open Approaches (When Endoscopic Fails)

Frontal Sinus Trephination

• Indicated for complicated acute or chronic frontal sinusitis, frontal osteomyelitis, far lateral sinus disease, or difficult-to-access super-agger cells

Osteoplastic Flap (with or without Obliteration)

• Indicated for recalcitrant frontal sinus disease after failed ESS, mucocele, osteomyelitis
• Bicoronal incision, inferiorly based bone flap hinged on pericranium, eradication of all frontal sinus mucosa
• Obliteration with fat, muscle or nonautologous material + occlusion of the frontal recess
• Mucocele formation many years later is still common

Riedel's Procedure

• Removal of the anterior table of the frontal sinus - causes cosmetic deformity, requires a second operation for cosmesis; largely of historical interest

Cranialization

• Removal of sinus mucosa and the posterior table - converts the sinus into an extension of the anterior cranial fossa; reserved for extensive posterior wall involvement

• Scott-Brown's Otorhinolaryngology Head & Neck Surgery Vol 1, Chapter 99 (FRONTAL SINUS SURGERY, Graduated approach - Table 99.3)
• Cummings Otolaryngology Head and Neck Surgery, Chapter 46 (Chronic Frontal Sinus Disease, Endoscopic Frontal Sinus Approach - Table 46.1)
• K.J. Lee's Essential Otolaryngology, Draf Classification and EFSS International Classification