Sinus obliteration

Sinus obliteration may be performed when endoscopically assisted transnasal opening of the frontal recess is not successful in re-establishing drainage leading to recurrent infections.

Sinus obliteration should also be considered when the sinus is entered when performing osteotomies in the supraorbital region and/or during cranioplasty procedures when a significant communication exists.

In these cases the access to the sinus is made through the existing osteotomies or a limited subcranial approach.

When the coronal approach is used to expose the frontal bone, it is critical to preserve the integrity of the pericranial flap if it has not been violated during the initial surgical intervention.

When a subcranial approach is performed, it is critical to determine the precise margins of the sinus to allow for an accurate osteotomy and exposure of the sinus. The margins of the frontal sinus are often irregular and may be depicted by trans illumination or a template obtained from a plain X-ray.

A 6-foot (1.83 m) Caldwell X-ray (anterior-posterior Caldwell X-ray with the patient placed 6 feet from the X-ray tube) can be used to delineate the margins of the sinus. The 6-foot penny Caldwell generates a “life-size” representation of the sinus cavity. It is imperative that the orientation (ie, right and left) is clearly documented on the X-ray.

Scissors are then used to cut along the margins of the sinus in the X-ray. Lateral “wings” that project along the orbital rims are also cut out to help with orientation. A second copy of the sinus template is generated from the first in case one is contaminated during the procedure. An “R” is scratched into the right side of both templates to record orientation. Both copies are sterilized and brought onto the surgical field.

The template is then placed over the sinus using the orbital rim “wings” to help with orientation. The template is held in place. The sinus periphery can then be outlined using ink or electrocautery as previously described.

After the proposed osteotomy has been marked, thin plates are applied spanning the sinus margin. An adequate number of plates should be applied to provide stability when the anterior table segment is replaced. The plates should be pre-applied prior to the osteotomy. This allows for accurate repositioning of the anterior table bone.

Each plate should be rotated away from the marked osteotomy line. This can be accomplished by removing all but one screw located on stable bone outside the osteotomy margin.

A sagittal saw or a side-cutting burr can be used to perform the osteotomy.

The handpiece should be angled approximately 45° towards the sinus and away from the cranial vault to avoid violation of the posterior table.

Next, the saw or drill is used to osteotomize the orbital rims and glabella. Care should be taken to protect the orbital contents and supratrochlear/supraorbital neurovascular pedicles.

Insert a curved osteotome through the superior osteotomy site and fracture the intersinus septum just deep to the anterior table bone. Care must be used to avoid injuring the posterior table.

A curved osteotome is then inserted through the superior osteotomy to cantilever the anterior table and generate a controlled fracture of any remaining attached bone. A clamp should be used to control the anterior bone fragment as the osteotomy fracture is completed.

The sinus cavity is then suctioned free of any blood or mucous. An elevator and/or forceps are used to remove any bone or mucosa that has been displaced into the sinus cavity.

Particular attention must be paid to the scalloped areas at the periphery of the sinus.

A clamp is used to stabilize the free anterior bone segment(s) that were previously removed. A large diamond burr is then used to remove the mucosa from the inner surface.

An elevator is then used to circumferentially elevate the mucosa in the frontal recess bilaterally. The mucosa is then removed or inverted and pushed inferiorly to obstruct the outflow tract. It is important that no mucosa remain in the frontal sinus. Free fascia can be used for obliteration of the outflow tract.

Alternatively, a sharp 1-2 cm straight osteotome can be used to harvest a thin layer of outer layer calvarial bone.

The bone graft fragments are trimmed to fit into the frontal sinus infundibulum using a fine bone rongeur.

The graft is then wedged into place to obstruct the sinus outflow ostia.

Cortical bone chips can be easily harvested from the previously exposed skull (coronal approach) with minimal morbidity by using a bone scraper.
Large sinuses can be more challenging to fill with bone. Nevertheless, demineralized bone matrix can be used in combination with bone chips when large amount of graft material is needed.

Frontal sinus obliteration using autogenous bone is the preferred method for most surgeons because its better outcomes and easier radiological follow up.

Alternatively, fat can be used as obliteration material. Further information can be found in the trauma section.

A pericranial flap can be used to obliterate small to medium size sinuses.
It has the advantage of being a vascularized flap. When using an osteoplastic bone flap, the bone flap may compress the blood supply to the pericranial flap thereby devascularizing it.

The pericranial flap must be inserted over the orbital rims and into the sinus. The reduced anterior table bone fragments must not compress the flap as it enters the sinus. A small bone slot (2-3 mm) must be generated to allow passage of the flap into the sinus.

The anterior table bone fragment is then repositioned and the pre-applied plates are rotated back into position to fixate the fragments.

Evaluation of the patient’s vision is performed as soon as they are awakened from anesthesia and then at regular intervals until they are discharged from the hospital.
A swinging flashlight test may serve in the unconscious and/or noncooperative patient; alternatively electrophysiological examination has to be performed but is dependent on the appropriate equipment visual evoked potential (VEP).

Keeping the patient’s head in a raised position both preoperatively and postoperatively may significantly improve edema and pain.

Nose-blowing should be avoided for at least 3 weeks following frontal sinus and skull base repair.

The use of the following perioperative medication is controversial. There is little evidence to make strong recommendations for postoperative care.

• No aspirin for 7 days (nonsteroidal antiinflammatory drugs (NSAIDs) use is controversial)
• Analgesia as necessary
• Antibiotics (many surgeons use perioperative antibiotics. There is no clear advantage of any one antibiotic, and the recommended duration of treatment is debatable.)
• Nasal decongestant may be helpful for symptomatic improvement in some patients.
• Steroids, in cases of severe orbital trauma, may help with postoperative edema. Some surgeons have noted increased complications with perioperative steroids.
• Ophthalmic ointment should follow local and approved protocol. This is not generally required in case of periorbital edema. Some surgeons prefer it. Some ointments have been found to cause significant conjunctival irritation.

Postoperative examination by an ophthalmologist may be requested. The following signs and symptoms are usually evaluated:

• Vision
• Extraocular motion (motility)
• Diplopia
• Globe position
• Visual field test
• Lid position
• If the patient complains of epiphora (tear overflow), the lacrimal duct must be checked
• If the patient complains of eye pain, a thorough ophthalmological evaluation should be performed.

Note: In case of postoperative diplopia, ophthalmological assessment is needed to identify the cause. Hess-chart testing should be performed if diplopia persists.

Postoperative imaging has to be performed within the first days after surgery. 3-D imaging (CT, cone beam) is recommended to assess complex fracture reductions. In centers where intraoperative imaging is available postoperative imaging can be performed at a delayed time.

For skull base and frontal sinus fractures postoperative imaging should be performed when indicated. If the frontal sinus is preserved, perform a follow up scan in 3-6 months to ensure that it is aerated.

The scalp can generally be washed at 5 days postoperatively.

Suture removal from scalp is performed at 7-10 days postoperatively.

Avoid sun exposure and tanning to skin incisions for several months.

Diet depends on the fracture pattern and patients condition but there are usually no limitations.

Patients should be counseled that frontal sinusitis, mucocele formation, or any other signs of intracranial infection can occur years after the injury. The symptoms should be discussed with the patient including

• Headache
• Erythema
• Mucopurulent nasal drainage
• Frontal bone deformity
• Orbital edema/displacement

Clinical follow-up depends on the complexity of the surgery, and the patient’s postoperative course.

• Other issues to consider are:
• Cranial vault contour deformity
• Sensory nerve compromise
• Problems of scar formation
• Alopecia
• Postoperative headache
• Anosmia
• Dizziness
• Vomiting
• Meningitis (can occur years after injury)
• Mucocele formation (can occur years after injury)

Implant removal is rarely required. It is possible that this may be requested by patients if the implant becomes palpable or visible. In some countries it will be more commonly requested. There have been cases where patients have complained of cold sensitivity in areas of plate placement. It is controversial whether this cold sensitivity is a result of the plate, a result of nerve injury from the original trauma, or from nerve injury due to trauma of the surgery. Issues of cold sensitivity generally improve or resolve with time without removal of the hardware.

Travel in pressurized aircraft is permitted 4 – 6 weeks postoperatively. Mild pain on descent may be noticed. However, flying in non-pressurized aircraft should be avoided for a minimum of 12 weeks.

No scuba diving should be permitted for at least 12 weeks. Additionally, the patient should be warned of long term potential risks.