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Basic Dissection

A. Intranasal Examination (Figure 11)

The structures of the posterior nasal choana (i.e., the eustachian tube opening, choanal arch, posterior septum, and posterior nasopharyngeal wall), along with the inferior turbinate, are routinely identified with a 0-degree or 30-degree telescope before proceeding with endoscopic surgery of the paranasal sinuses. Identification of these structures early on establishes the anteroposterior dimensions of the nasal airway, provides a drainage route for blood into the nasopharynx, and facilitates the introduction of endoscopic surgical instrumentation and telescopes. Hypertrophied middle and/or inferior turbinates, and/or a septal spur or deviation obstructing the nasal airway or limiting endoscopic exposure, are addressed prior to proceeding with any sinus work. When bilateral polyp disease is present, a bilateral nasal polypectomy is performed first to re-establish the antero-posterior dimensions of the nose, as well as to facilitate the placement of a contralateral naso-pharyngeal suction.

Hemostasis and adequate nasal exposure and evacuation of blood are imperative, especially when addressing advanced inflammatory disease of the nose and paranasal sinuses. A separate contralateral suction is used for the continuous evacuation of accumulated blood and debris from the nasopharynx. The nose is topically decongested and infiltrated with vasoconstrictive agents. Monopolar or bipolar suction cautery is helpful if discrete bleeding vessels are encountered during surgery. However, excessive cauterization should be avoided to minimize crusting and prolonged healing in these areas.

Antero Inferior Naso SeptumInferior Turbinate Bleeding

Figure 11 Sagittal (a) and endoscopic (b and c) views of the internal nasal structures. IT = inferior turbinate. MT = middle turbinate. ST = superior turbinate. SP = supreme turbinate. IM = inferior meatus. MM = middle meatus. Asterisks = sphenoethmoidal recess. LS = lacrimal sac. D = lacrimal duct. PF = posterior fontanelle. NS = nasal septum. ET = eustachian tube orifice. Small arrows in the endoscopic view denote the posterior choanal arch.

Figure 11 Sagittal (a) and endoscopic (b and c) views of the internal nasal structures. IT = inferior turbinate. MT = middle turbinate. ST = superior turbinate. SP = supreme turbinate. IM = inferior meatus. MM = middle meatus. Asterisks = sphenoethmoidal recess. LS = lacrimal sac. D = lacrimal duct. PF = posterior fontanelle. NS = nasal septum. ET = eustachian tube orifice. Small arrows in the endoscopic view denote the posterior choanal arch.

B. Inferior Turbinoplasty (Figure 12)

An endoscopic inferior turbinoplasty may be indicated when there is poor endoscopic visualization of the nasal and posterior choanal structures or nasal obstruction due to turbinate hypertrophy (38,39). Frequently, the turbinate bone is the primary cause of turbinate hypertrophy and nasal obstruction (40). The inferior edge of the inferior turbinate, adjacent to the nasal floor, is incised or de-epithelialized to expose the turbinate bone along its entire extent with a 30-degree telescope looking slightly superolaterally. A medial mucosal flap is raised and the turbinate bone is partially or totally removed in a piecemeal fashion. To minimize the chance of secondary maxillary sinusitis, care should be taken to avoid fracturing the inferior turbinate lamellar attachment to the lateral nasal wall (41). For additional airway space, the lateral (inferior meatal) mucosal flap is trimmed as needed. At the completion of the procedure, the medial and lateral mucosal flaps are reapposed along the entire anteroposterior extent of the inferior turbinate. This minimizes the chance of prolonged crusting due to exposed bone (osteitis) or de-epithelialized surfaces.

Medial Flap Turbinoplasty
Figure 12 Dotted line demarcates the incision for an inferior turbinoplasty. This can be performed with a cutting forceps, sickle knife, or powered instrumentation.

C. Septoplasty (Figures 13 and 14)

A significant septal spur or deviation may preclude adequate endoscopic visualization or adversely affect nasal airway patency. In these cases an endoscopic septoplasty may be indicated (42-45). An endoscopic septoplasty begins with the elevation of an L-shaped posterosuperiorly based mucoperiochondrial flap. The 30-degree telescope is rotated to look slightly superomedially. Care is taken to place the vertical portion of the incision immediately anterior to the deviated area to facilitate cartilage or bone removal. The mucosal incision should be made only through the mucosa on the ipsilateral side. The horizontal portion of the incision is made perpendicular to the vertical incision at the junction of the floor and nasal septum or just slightly superior to this point, depending on the extent of the deviation. The contralateral mucoperichodrium is identified and preserved, especially at the incision area, to avoid the chance of a permanent septal perforation. The septal spur or deviated portion of the nasal septum is removed and the mucoperichondrial

Figure 13 Endoscopic view showing the proposed incision (dotted line) for the L-shaped posterosuperiorly based mucoperichondrial flap. NS = nasal septum. MT = middle turbinate. IT = inferior turbi-nate. Asterisk denotes a septal spur.
Slightly Deviated Septum
Figure 14 Endoscopic view showing the ipsilateral mucoperichondrial flap (arrows) is elevated toward the inferior turbinate. Bone or cartilage is carefully removed while preserving the contralateral mucoperichondrium (MP).

flap is returned to its normal position. Occasionally it is necessary to remove a strip of perpendicular plate cartilage or bone inferior to the rhinion area in order to free up a caudal deflection. Nevertheless, a dorsal and caudal strut of septal cartilage is always preserved to avoid the chance of septal collapse and saddle-nose deformity. At the conclusion of the procedure, the vertical septal incision may be sutured, although this is usually not necessary unless the flap interferes with the introduction of the telescope or instruments. Otherwise, blood is allowed to drain through the horizontal incision to minimize the chance of hematoma formation. Packing or basting sutures are generally not required unless the septal incisions are sutured.

D. Middle Turbinoplasty (Figures 15 and 16)

When the middle turbinate is enlarged, a middle turbinoplasty may be indicated (46,47). Middle turbinate enlargement may be due to mucosal hypertrophy or a concha bullosa. Middle turbinate reduction may be indicated to improve access to the middle meatal structures. It may also be necessary for sphenoethmoidal recess and sphenoid ostium exposure.

A conservative reduction of the middle turbinate head may be performed whereby visualization of the middle or superior meatal structures is improved without adversely affacting olfaction, ostial drainage from the anterior ethmoids or frontal sinuses, or the patient's airway (48,49). Care is taken to sharply resect the middle turbinate head while not fracturing or de-epithelializing the vertical lamella of the middle or superior turbinates adjacent to the olfactory cleft. The mucosal membranes on the medial and lateral aspect of the turbinate are also preserved, especially around the "axilla" of the middle turbinate. When a concha bullosa is reduced, a greater portion of the medial lamella is preserved to protect the olfactory cleft.

Figure 15 Sagittal view denoting the extent of middle turbinate head resection (dotted line) to expose the middle meatal or sphenoethmoidal recess structures. The vertical lamella of the middle turbi-nate and the superior turbinate are left undisturbed and unfractured.

Figure 16 Sagittal (a) and endoscopic (b) views after middle turbinoplasty. The circle demarcates the nasolacrimal duct convexity in the anterior lateral nasal wall. IT = inferior turbinate. T = tail of the middle turbinate. B = ethmoid bulla. U = uncinate process. PF = posterior fontanelle with an accessory maxillary sinus ostium. The solid inverted S-shaped line in the sagittal view denotes the basal lamella of the middle turbinate as it courses toward the orbital wall. H = horizontal portion of the basal lamella, where one would typically enter the posterior air cells in distorted sinus cavities. V = vertical portion of the basal lamella separating the suprabullar air cells from the superior posterior ethmoid air cells. Small arrows represent the vertical lamella of the middle turbinate.

Figure 16 Sagittal (a) and endoscopic (b) views after middle turbinoplasty. The circle demarcates the nasolacrimal duct convexity in the anterior lateral nasal wall. IT = inferior turbinate. T = tail of the middle turbinate. B = ethmoid bulla. U = uncinate process. PF = posterior fontanelle with an accessory maxillary sinus ostium. The solid inverted S-shaped line in the sagittal view denotes the basal lamella of the middle turbinate as it courses toward the orbital wall. H = horizontal portion of the basal lamella, where one would typically enter the posterior air cells in distorted sinus cavities. V = vertical portion of the basal lamella separating the suprabullar air cells from the superior posterior ethmoid air cells. Small arrows represent the vertical lamella of the middle turbinate.

Basal Lamella Middle Turbinate Vertical

E. Uncinectomy and Identification of the Maxillary Natural Ostium (Figures 17-19)

Using an angled probem the uncinate process, hiatus semilunaris, and infundibulum are identified. The uncinate process is gently backfractured with an angled probe and carefully removed with a backbiting forceps or powered instrumentation to expose the lateral (orbital) wall of the infundibulum and maxillary sinus natural ostium. Care is taken to conserve the mucosal membranes of the adjacent lateral infundibular wall and ethmoid bulla. In addition, the tail or postero-inferior remnant of the uncinate may occlude the natural ostium. This must be identified and removed in order to see the natural ostium of the maxillary sinus. The superior border of the nat

Figure 17 Sagittal (a) and endoscopic (b) views illustrating the degree of uncinate resection (dotted line) just behind the convexity of the nasolacrimal duct. B = ethmoid bulla. The small circle denotes the approximate location of the maxillary sinus natural ostium behind the uncinate process.

Figure 17 Sagittal (a) and endoscopic (b) views illustrating the degree of uncinate resection (dotted line) just behind the convexity of the nasolacrimal duct. B = ethmoid bulla. The small circle denotes the approximate location of the maxillary sinus natural ostium behind the uncinate process.

ural ostium demarcates the junction of the medial orbital floor (MOF) with the lamina papyracea. The lateral wall of the infundibulum demarcates the medial orbital wall (inferiorly).

For more limited disease of the ostiomeatal complex, an uncinectomy, exposure of the maxillary natural ostium, and a limited antrostomy may be all that is necessary. However, if there is significant anatomical distortion, then the MOF should be identified through a wide middle meatal antrostomy prior to proceeding with an ethmoidectomy. As the surgeon gains more experience, this step may merely require vizualizing the superior margin of the maxillary sinus natural ostium (representing the anterior MOF), obviating the need for a wider antrostomy.

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