Taking note of anatomic variations and potential causative mechanisms of CSF fistulae is critical; our experience with this case suggests a possible third mechanism of injury to the delicate cribiform plate during septoplasty--i.e., during insertion of intranasal splints--and certainly serves to emphasize the importance of their cautious insertion under direct vision to avoid overdisplacement of the middle turbinate and subsequent injury to the cribiform plate.
Cartilage manipulation during septoplasty and subsequent insertion of the splints might have led to destabilization of the superior attachment of the middle turbinate to the cribiform plate in our patient.
The spontaneous resolution of CSF rhinorrhoea upon splint removal suggests that the Silastic splint had pushed the right middle turbinate into an overlateralized position, further weakening the superior attachment of the middle turbinate to the cribiform plate and causing a fine fracture defect (figure 2).
Two other mechanisms of injury to the cribiform plate have previously been postulated in the development of iatrogenic CSF rhinorrhea after septoplasty.
Those thin, spaghettilike nerves run from the nose through an opening in a skull segment called the cribiform plate
. Head trauma can sever the nerves, or if an injury shatters the plate, its aperture may close as the bone mends.
When lymphatics of the cribiform plate are blocked, hindering CSF absorption, intracranial pressure (ICP) is raised.
It drains via the cribiform plate, transporting antigens within it to deep cervical lymphatic vessels and nodes(1,16).
The important lymphatics of the cribiform plate area are accessed in this way and deep breathing potentiates lymphatic flow in the thoracic duct.
The cribiform plate, accessed via medial eye puncta and nasal areas, is treated first, then the zygomatic tract, auricular nodes and mastoid process.
No definitive areas of bony deficiency in the cribiform plate were seen, but there was a questionable defect on the roof of the left ethmoid sinus (figure 1,A-C).
(6,7) The increasing use of powered microdebrider instruments along the skull base and thin bones of the cribiform plate and ethmoid sinus may be associated with a greater incidence of pneumocephalus after FESS.
If intracranial extension is present, it classically occurs through the foramen cecum or cribiform plate
and attaches extradurally to the falx cerebri.