Frontal sinusotomy

The frontal sinuses are the most difficult sinuses to treat surgically by the endonasal route, as they are located plumb to the eyes, i.e. laterally and very slightly posterior to the nostril orifices in vertical projection. The orientation of their “naso-fronta” drainage channels in the nose is therefore from front to back and from outside to inside, in another sinus, the ethmoid. To open the frontal sinus, the ethmoidal sinus must first be opened. Working with optics angled at 30° or even 70° increases the difficulty, as the surgeon is not working in the axis of his optics. Specific instruments with very pronounced angles must also be used. The main reasons for opening one or both frontal sinuses are antibiotic-resistant bacterial sinusitis, which cannot drain naturally, and mucoceles.
Mycoses and benign or malignant tumors are much rarer indications in these sinus.

Find out more about endonasal frontal sinus openings from Dr. Delagranda, ENT and cervico-facial surgeon in La Roche sur Yon, France.

The frontal sinuses are sinuses located above the eyes, often asymmetrical, poorly developed in 4% of cases (hypoplasia) and even absent in 5% of cases (aplasia or agenesis). They arise from an invagination of the ethmoidal sinus at the embryonic stage, which explains why they drain into the ethmoid. Present from birth, they develop most rapidly from the age of 6. Their main roles are to act as a sounding board for the voice, to help warm, humidify and filter the air breathed in, and to lighten the face while giving it the capacity to absorb violent shocks, without affecting the noble organ that is the brain. Indeed, in the event of an accident, an anterior fracture of the frontal sinus is preferable to a perforation of the brain.

The nasofrontal drainage canal is larger than 3 mm, and the frontal ostium is smaller. The frontal sinus drains directly into the ethmoidal sinus, but in different ways. Occasionally, the drainage zone between several ethmoidal cells is very narrow and, as a result of persistent inflammation, becomes totally blocked. This can lead to acute or chronic sinusitis, which may remain unresolved despite antibiotic and anti-inflammatory treatment. In such cases, traditional opening surgery, as described below, or the use of balloons may be required.

Mucoceles are hermetic mucous pockets originating from sinuses that can no longer drain. Not specific to the frontal sinuses (they are also found in the ethmoid and more rarely in other sinuses), they are quite common in the frontal sinuses because their drainage passes through a narrow canal. Mucoceles most often develop in people with previously operated nasosinus polyposis. Filled with mucus permanently secreted by the mucocele walls, they tend to grow inexorably, as the mucus cannot evacuate. The rate of growth of mucoceles varies from person to person, but it can lead to progressive deformation of the bone over months or years, until rupture occurs, sometimes with serious consequences (meningitis, brain abscess or empyema, exophthalmos, double vision, reduction or loss of sight). Antibiotic and corticosteroid treatments can be used on an ad hoc basis in the event of early complications, prior to rapid surgery. Mucoceles are merely the translation of an underlying problem that may never be resolved, so they can recur, sometimes years later. Mucoceles are monitored by MRI, and should be done regularly. Any change in the mucocele should be booked promptly.

Draf and Lothrop are the names of surgeons who have described operations on the frontal sinus, creating classifications based on the degree of opening required in relation to the medical context.

Classification de draf

Endonasal opening of the frontal sinus should be performed in cases of :

Bacterial frontal sinusitis resistant to several lines of usually effective antibiotics : intense, pulsatile frontal pain, predominant on one side, increased when the head is tilted forward, with or without fever, runny or stuffy nose (rhinorrhea), which may or may not be blocked (nasal obstruction) on one side only.

Frontal mucocele : mucocele is usually initially asymptomatic. Pain is rare, but a deformity of the forehead, an eye protruding from its socket (exophthalmia), double vision and a progressive or abrupt, partial or total loss of visual acuity can also be observed. These last 3 signs constitute an emergency to consult.

Benign or malignant tumor of the frontal sinus, often not limited to this sinus alone : signs can therefore be highly variable: cranial or facial pain, blocked nose (nasal obstruction) that runs (rhinorrhea) or bleeds (epistaxis) on one side only.

Fungal sinusitis, which is exceptional in the frontal sinuses : asymptomatic at first, most of the time. Signs can therefore vary widely, from no signs at all and an incidental finding on a skull scan, for example, to frontal pain, blocked nose (nasal obstruction) and runny nose (rhinorrhea) on one side only.

With no externally visible scar (except for a possible 2 mm scar on the forehead for temporary placement of a brow nail), the procedure is performed through the nasal cavity. Under general anaesthetic in the operating theatre, the nasal cavities are cleaned with an anaesthetic-retractant, then the ethmoidal cell walls are removed with suitable forceps, under visual control using rigid optics inserted into the nose, keeping the walls in contact with noble organs such as the eyes and brain.  Depending on the indication, it may be necessary, with the help of neuronavigation, to mill the bone behind the nose and remove an upper, anterior part of the nasal septum (without external aesthetic repercussions). A mucosal transposition flap can be made within the nose itself. A healing foam gel is then placed in the 2 operated nostrils, and in some cases a semi-rigid silicone sizing is applied, to be removed at a later stage.

In the case of outpatient surgery, the patient usually returns home the same day.
After hospitalization, you will need to rest at home for 7-14 days, and check that there is no bleeding from the nose or throat.
If necessary, the surgeon will give you 14 to 21 days off work, depending on the procedure.
Sport is not recommended for the first 21 days, and recovery should be gradual.
Pain is moderate. It is controlled by class II analgesics.
Post-operative care at home: saline nosewash, analgesics, antibiotics if required by your doctor. Removal of silicone sizer in consultation on the date set by the surgeon.
Scarring: no visible scarring unless a brow nail has been inserted (2 mm punctiform scar between the eyebrows).

Here is a selection of questions frequently asked by Dr Delagranda’s patients during consultations for endonasal frontal sinus surgery in La Roche-sur-Yon.