Subcranial approach implies working through the frontal sinus to get access to the central compartment of the anterior cranial fossa. Defects affecting the posterior sinus table as well as mid-size to larger defects affecting the cribriform plate and frontal recess are the most common indications for this procedure.
Alternatively a neurosurgical transcranial approach may be chosen to repair these defects.
The standard approach is a coronal incision. However, previous craniotomy incisions may also be utilized.
The subcranial approach is used to access the central compartment of the anterior cranial fossa.
Extradural dissection is performed in the central portion of the anterior cranial fossa around the cribriform plate. Division of the olfactory nerves is carried out as needed.
The amount of posterior dissection will depend on the extent and location of the defect. Elevation of the subfrontal dura from the planum sphenoidale can reach as far as the tuberculum sellae and the medial sphenoid ridge.
3. Dural repair
In the case of a significant bony defect, the defect can be grafted.
After appropriate exposure, the dural defect is repaired using a substitute that may be glued to the margins. This can be done in different layers either intra or extra dural.
The pericranial flap is brought in and should reline the bone defect of the anterior skull base. Whenever possible, the pericranial flap should be sutured to the dura.
Replace the bone flap using microplates and screws in a stable three point fixation technique.
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.
4. Aftercare following open management of skull base corrections
General postoperative care
Intensive care 24 hours
Hospitalization 5-8 days (to rule out reoccurrence of CSF leak)
The use of broad-spectrum antibiotics during and after the procedure for the next 5-7 days is recommended.
Radiologic control examinations are performed routinely the next day after leaving the intensive care unit.
Patient follow-up after discharge. The patient is seen 4 weeks after, and if necessary, for the long-term follow-up a year postoperatively.