Endoscopic Sinus Surgery_2_

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					ENDOSCOPIC SINUS SURGERY
             Section 5 (‫)قسمت پنجم فایل‬




     Bakhshaee M, MD
     Rhinologist, Assistant Prof. MUMS
Frontoethmoidectomy
Frontal Sinusotomy (I, II, III)
Frontoethmoidectomy
   This procedure involves opening of the frontal recess
    together with an anterior ethmoidectomy
Frontal sinusotomy I
    No instrumentation of the frontal recess is required
     when the uncinate process is attached to the skull
     base or middle turbinate; when the uncinate process
     has been removed, the recess is open unless there
     are:
1.    Large agger nasi air cells
2.    Bulla frontalis
3.    Supraorbital cell
Frontal sinusotomy II
   Enlarging the frontal recess by the submucosal
    removal of agger nasi air cells, bulla frontalis, or a
    supraorbital cell.
Frontal sinusotomy III
   Extended enlargement with removal of the
    frontonasal spine or “beak”.
    There are few other reasons for operating on the
     frontal recess before trying a partial anterior
     ethmoidectomy.
    These include:
1.    The presence of fungal disease in the frontal sinus
2.     Mucocele
3.    Osteoma
4.    Other pathology in this area that requires wide exposure
      for access.
   Access to the frontal recess may be altered by the
    attachment of the uncinate process
Type A
   Where the uncinate process attaches to the lateral
    nasal wall so the frontal sinus drains into the middle
    meatus
Type B1
   The uncinate process attaches to the skull base
Type B2
   The uncinate process attaches to the middle
    turbinate
Agger Nasi & Bulla Frontalis
   A high anterior ethmoidal cell that has pneumatized
    into the frontal bone is called the bulla frontalis and
    this can displace the frontal recess posteriorly
Supraorbital cell
   The supraorbital cell extends up into the frontal
    sinus posterior to the frontal recess.
   Supraorbital cell can extend over the skull base
Surgical Technique

   The surgeon must have a good
    reason for operating in this area.

   The landmarks that will help you
    are the remains of the uncinate
    process, the remainder of the
    anterior wall of the ethmoid bulla,
    and a knowledge of the air cells
    from the CT scan.
   Uncapped agger nasi cells,
    the terminal recess, and the
    ethmoid bulla form domes
    that are joined together.
   It often appears that this is all
    there is and they might fool
    you into thinking that one of
    them is a small frontal sinus.
   The aim is to open this crevice,
    which will turn out to be the
    pathway to the frontal recess
    and the frontal sinus, by
    “deflating” the cells.
   This is best done by passing the
    ball probe well above their
    domes and gently lateralizing
    them.
Anterior ethmoid artery
   You should not go searching for the anterior ethmoid
    artery as it is not a useful landmark and to do so is
    dangerous.

   It is important to be aware that it is partially dehiscent
    in 20% of patients.

   If the skull base is very well pneumatized, the artery
    can even be free like a tightrope, especially if there is
    a large supraorbital cell.
Sphenoethmoidectomy
    This is an extension of a partial anterior
    ethmoidectomy that involves surgery into the
    posterior ethmoid sinuses and the sphenoid sinus
Sphenoid sinusotomy
    A sphenoid sinusotomy is a transnasal approach to
    open the sphenoid sinus

   Sphenoid sinusotomy can be classified into types I,
    II, and III depending on its size.
Onodi Cell
   A sphenoethmoid (Onodi) cell
    has part of its extension lateral
    to the lateral wall of the
    sphenoid, which means that the
    optic nerve is likely to be
    exposed
Anatomy
   Its natural ostium lies high in the anterior wall of the
    sphenoid and can be hidden by the superior and
    middle turbinates
   The roof of the sphenoid sinus is a reliable
    landmarkand the posterior ethmoid sinuses do not
    drop below this horizontal level of the skull base
   The vomer meets the sphenoid in the midline, but the
    sphenoid inter sinus septum is symmetric in over
    75% of patients
   The lateral wall of the sphenoid contains the carotid
    artery, which is dehiscent in 30% of patients
   The superolateral aspect of the sphenoid sinus
    contains the optic nerve, which is visible in 20% of
    patients
Surgical Technique
   The posterior ethmoidal cells are entered through
    the basal lamella and it is safest to enter these
    medially and inferiorly.
   Enlarge access to these cells and avoid making a
    tunnel.
   Always find the sphenoid sinus transnasally first if
    you intend opening up all the posterior ethmoid
    sinuses.
landmarks to avoid traversing the boundaries of the paranasal
sinuses


   Check the CT scan to see that there is no Onodi cell
    as the optic nerve can sometimes be dehiscent in its
    lateral wall.
   Look at the posterior coronal CT slices of the
    maxillary sinus and look at the height from the roof
    of the maxillary sinus to the roof of the skull base.
   Sometimes this can be spacious but sometimes it is
    small and it will give the operator an idea of the
    extent of the posterior ethmoidal air cells.
Landmarks
   The roof of the sphenoid sinus is a useful landmark
    as the posterior ethmoid sinuses are not lower than
    it.

   The posterior ethmoid sinuses that lie medial to the
    medial wall of the maxillary sinus in a sagittal
    plane can be removed without concern that the
    optic nerve or orbit will be damaged.

				
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posted:6/3/2012
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