Bulla Ethmoidalis

Ethmoidotomy

The term "ethmoidotomy" will be used instead of "ethmoidectomy" since the aim of endonasal surgery for inflammatory diseases is generally to remove all the bony septa which made up the ethmoid labyrinth apart from the peripheral walls of the box, which are left intact. Any effort should also be paid to preserve as much as possible the peripheral mucosa, thus avoiding denudation of the bone and slowing of the healing process. The use of cutting instruments and of a microdebrider, which has been designed for precise removal of only soft tissues, helps tremendously in obtaining a very conservative dissection.

The bulla ethmoidalis is usually the largest and more constant cell of the anterior ethmoid: its open-

ing is recommended at the level of the inferomedial corner, a safe area far away from the lamina papyra-cea and the skull base. After the bulla has been removed (Fig. 5.7), the course of the ground lamella can

Ground Lamella
Fig. 5.7. The bulla ethmoidalis has been removed. A, agger nasi; PE, posterior ethmoid; FS, frontal sinus; IT, inferior turbinate; SS, sphenoid sinus

usually be followed with the endoscope. Its identification may be difficult because of pathologic changes or anatomic variations and also because it is not always a smooth flat bony plate. If the posterior ethmoid must be opened, the ground lamella should be perforated on its inferomedial corner. It is of paramount importance not to remove the inferior part of the lamella, which would result in destabilization of the middle turbinate with a high risk of lateralization and secondary closure of frontal recess and maxillary ostium. The posterior ethmoid is now accessible and the surgeon proceeds to open all the cells to obtain an adequate marsupialization (Fig. 5.8). During the dissection along the lamina papyracea, special care should be taken not to injure and transgress it, with

Posterior Ethmoidal Cells
Fig. 5.8. The ground lamella has been perforated to approach the posterior ethmoidal cells. A, agger nasi; PE, posterior ethmoid; FS, frontal sinus; IT, inferior turbinate; SS, sphenoid sinus

the potential risk of determining a lesion of the medial rectus muscle or of the optic nerve. The presence of an Onodi cell, which by definition contains in its lateral wall the optic nerve, should be identified on CT scan and kept well in mind by the surgeon during this phase of the operation.

One of the major sources of debate among rhi-nosurgeons is how to manage the middle turbinate during ethmoid surgery. In our opinion, every effort should be made to spare this anatomic structure, which plays an important role in modulating the air flow through the nasal fossa and also contributes to olfactory function, but there are indeed situations, when it becomes unstable or it is covered by a mucosa with massive polypoid changes, which make its sacrifice necessary. Whenever the surgeon is faced with a pneumatized middle turbinate which is itself diseased or causes obstruction of the ostiomeatal complex, a partial sagittal turbinectomy, leaving intact the medial part, is indicated (Fig. 5.9).

and, on the other, by the anatomical configuration of each single patient. A transnasal approach to the sphenoid sinus is generally elected when an isolated disease of the sinus is present and there is enough space between the septum and the middle-superior turbinates to have direct access to the sphenoethmoid recess and the sphenoid ostium. Whenever the surgeon is faced with an unfavorable anatomic situation or the disease involves both the ethmoid and the sphenoid, the transethmoid approach is preferable. However, one should keep in mind that a transeth-moid approach does not lead to the anterior wall of the sphenoid in the region of its natural ostium, but superiorly and laterally to it. Access to the sinus has therefore to be gained inferiorly and medially by down-fracturing the anterolateral wall; sphenoid-otomy is then progressively enlarged to include the sphenoid ostium. An alternative technique (Bolger et al. 1999; Orlandi et al. 1999), which we personally prefer for its safety, consists first in the identification of the sphenoid ostium by resecting the inferior part of the superior turbinate, and subsequently in its progressive enlargement in an inferolateral direction.

Whatever technique has been chosen, the size of a sphenoidotomy should be large enough to prevent any possible scar closure (Fig. 5.10).

Middle Turbinectomy
Fig. 5.9. On the left, a concha bullosa (CB) is represented. On the right, a partial sagittal turbinectomy, leaving intact the medial part, has been performed

Fig. 5.10. A wide sphenoidotomy has been performed. A, agger nasi; FS, frontal sinus; IT, inferior turbinate; SS, sphenoid sinus

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Responses

  • Toby
    What is the polypoid disease was removed to the ground lamella?
    7 years ago

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