Middle and Inferior Turbinates




Abstract


The inferior and middle turbinates are often considered a source of obstruction, usually airway obstruction for the inferior turbinates and sinus obstruction for the middle turbinates. Prior to embarking upon surgical treatment, the surgeon is reminded that these are functional structures. This chapter reviews strategies, techniques, and outcomes of turbinate surgery. Anatomy and physiology are discussed, as well as potential pearls and pitfalls in surgical treatment. Individual techniques are described in stepwise fashion, and the limited knowledge of comparative outcomes with different techniques is explored.




Keywords

anatomy and physiology, nasal obstruction, surgery, turbinates

 




Introduction





  • Turbinate surgery is performed most commonly to treat obstruction. Examples are nasal airway obstruction caused by oversized inferior turbinates and obstruction of sinus drainage by a lateralized middle turbinate or concha bullosa.



  • The middle and inferior turbinates are dynamic functional structures within the nasal cavity and sinuses. Anatomic variations and/or dysfunction commonly lead to the need for turbinate reduction or resection.



  • Total resection of an inferior turbinate is the extreme and is generally not recommended in most cases except for neoplasm resection ( Fig. 2.1 ).




    Fig. 2.1


    Endoscopic view of the right nasal cavity after near total inferior turbinectomy. Patients with such extensive turbinate resection are at risk for atrophic rhinitis.





Anatomy and Physiology





  • The turbinates comprise a set of three paired laminar structures that arise from the lateral wall and roof of the nasal cavity.



  • The inferior turbinate is its own laminar structure; the middle and superior turbinates form part of the ethmoid bone.



  • Each turbinate is composed of a bony base covered by respiratory epithelium with an intervening submucosal layer.



  • Although the functions of the turbinates are not completely understood, it is known that they help to optimize oxygen exchange in the lungs by warming, humidifying, and filtering inspired air.



  • The turbinates also assist in maintaining directional and laminar airflow in the nose and contribute to olfaction by directing air toward the olfactory cleft.



  • The submucosa of the inferior turbinate contains a complex system of capacitance vessels that allow for selective engorgement or decongestion of the submucosal tissue. This change in turbinate thickness alters both the cross-sectional diameter of the nasal airway and the surface area of the turbinate.



  • Fluctuations in vasomotor tone of the turbinates may be based on the temperature and humidity of inspired air and overall sympathetic tone of the individual.



  • The cross-sectional area of the nasal cavity can also be altered by inflammatory swelling of turbinate soft tissue.





Preoperative Considerations





  • When considering turbinate surgery, the surgeon should always remember that the turbinates are functional organs.



  • Techniques should target the submucosal tissue, leaving the functional mucosa intact and undisturbed.



  • Bleeding can be minimized by timely injection of 1:100,000 epinephrine (usually in combination with an anesthetic such as 1% lidocaine).



  • Inferior turbinate outfracture does not address the vasoactive components of turbinate hypertrophy and is generally not sufficient as a standalone procedure.



  • The surgeon should remember that the anterior-most 2 cm of the inferior turbinate account for the majority of its impact on patency of the nasal airway.



  • Dissection posteriorly can injure larger vessels branching off the sphenopalatine artery as they enter the turbinates posteriorly.



Radiographic Considerations





  • Radiologic imaging is not necessary to assess the inferior turbinates.



  • For the middle turbinates, closely evaluate the axial and coronal computed tomographic scans.



  • Identify the inferior and middle turbinates. Identify the nasolacrimal duct and take note of its location in relation to the inferior turbinate and inferior meatus.



  • Identify the presence of any concha bullosa and note the anatomy of the middle turbinate as it inserts on the skull base. Prior surgical manipulation of the middle turbinate may predispose to middle turbinate lateralization, which may adversely affect drainage of the frontal or ethmoid sinuses.



  • Assess the size and patency of the nasal cavity as well as the possible contributions of the inferior and middle turbinates, nasal septum, and other anatomic structures on nasal obstruction.





Instrumentation





  • 0-degree and 30-degree endoscopes



  • Boies-Goldman elevator



  • Freer elevator



  • Microdébrider with turbinate blade or pediatric cutting blade



  • Monopolar or bipolar radiofrequency ablation device (optional)



  • Monopolar needle electrocautery device (optional)



  • Sickle knife or scalpel



  • Straight and angled through-cutting forceps



  • Endoscopic scissors





Pearls and Potential Pitfalls





  • Care should be taken when operating on the turbinates, with the goal being to preserve or restore normal function.



  • The most conservative procedure that can accomplish this goal is the best option. Techniques involving greater degrees of tissue resection or ablation should be reserved for treatment failures.



  • Thermal injury caused by aggressive soft tissue reduction of the inferior turbinate can result in problematic complications such as mucosal sloughing and crusting.



  • Surgery directed at the more posterior portions of the inferior or middle turbinate is generally less necessary to improve the nasal airway but can be associated with an increase in the risk of arterial bleeding.



  • Overresection of the inferior turbinates may, in rare cases, lead to paradoxic nasal obstruction or empty nose syndrome (see Fig. 2.1 ). Therefore, a judicious approach to turbinate resection is indicated.





Surgical Procedures


Surgery of the Inferior Turbinate





  • Nasal obstruction is the primary indication for inferior turbinate surgery.



  • Some evidence exists to support the use of inferior turbinate surgery to improve the symptoms of allergic rhinitis.



  • Other indications include maxillary sinus hygiene, chronic rhinitis, and snoring.



  • Surgery of the inferior turbinate can be classified into a sequence ranging from least invasive to most invasive: outfracture, soft tissue resection/reduction, resection of bone and soft tissue, and full-thickness resection of the anterior portion.



Inferior Turbinate Outfracture





  • Outfracture is the simplest and least invasive of the inferior turbinate procedures because no tissue is removed.



  • Because outfracture does not modify soft tissue, the vasoactive components of turbinate hypertrophy are not addressed by this technique.



  • The inferior turbinate bone attaches to the lateral nasal wall at an angle, so that outfracture requires pressure on the bone in an inferior-lateral, not just lateral, direction.



  • Gentle technique is necessary to avoid injury to the orifice of the nasolacrimal duct in the lateral wall of the inferior meatus.



Step 1





  • Under direct visualization, place a Freer or similar elevator within the inferior meatus and fracture the turbinate upward and medially ( Fig. 2.2A ).




    Fig. 2.2


    Artist’s depiction of inferior turbinate outfracture in endoscopic view. (A) The inferior turbinate is medialized so that the fracture point of the bone is at the attachment of the lateral nasal wall. (B) The inferior turbinate is lateralized with a Freer or Boies-Goldman elevator to create a larger inferior airway.



Step 2





  • Place a Boies-Goldman or Freer elevator on the superior and medial surface of the turbinate and outfracture it laterally and inferiorly ( Fig. 2.2B ).



Inferior Turbinate Soft Tissue Reduction





  • Many techniques can be used to address the soft tissue of the inferior turbinates, which have their own advantages and disadvantages ( Table 2.1 ).




    • Thermal ablation: (1) Electrocautery, (2) Laser



    • Radiofrequency: (1) Bipolar, (2) Unipolar



    • Microdébrider



    TABLE 2.1

    Different Surgical Techniques for Inferior Turbinate Reduction With Advantages And Disadvantages for Each Technique
























    Surgical Technique Advantages Disadvantages
    Electrocautery/diathermy Minimally invasive Unmeasured delivery of energy
    May necrose mucosa if not careful
    Laser ablation Minimally invasive
    May be performed in the office
    Equipment costs
    Not mucosal sparing
    Long-term results vary
    Radiofrequency (bipolar, unipolar) Minimally invasive
    Minimal discomfort
    Mucosal sparing
    Less control over degree of tissue reduction
    Equipment cost
    Microdébrider Can sculpt turbinate, especially for severe hypertrophy
    Can be performed in clinic or operating room
    Mucosa preserved
    Risk of bleeding



  • Some devices that use thermal or radiofrequency energy remove tissue to some degree but work largely by causing wound contraction.



  • Most, but not all, techniques target the submucosal tissue while leaving the functional mucosa intact.



  • Submucosal needle electrocautery is, in many ways, the simplest of these techniques but is also very imprecise.



  • Laser ablation essentially resurfaces the mucosa, with some ablation of the submucosa as well. The equipment costs can be substantial.



  • Ablation and electrocautery both subject the overlying mucosa to thermal injury, which sometimes results in mucosal sloughing and crusting.



  • Radiofrequency devices for performing inferior turbinate reduction can be either unipolar or bipolar; no appreciable difference in outcomes is seen with the two methods.



  • The impact of soft tissue reduction on the nasal airway is largely due to alterations in the anterior portion of the inferior turbinate. Reduction posteriorly does not significantly improve the nasal airway and can significantly increase the risk of bleeding.



  • Several careful analyses of outcomes following inferior turbinate surgery have been performed over the last few years.



  • A large study comparing subtotal turbinectomy, laser cautery, electrocautery, cryotherapy, submucosal resection, and submucosal resection combined with outfracture found the best outcome at 6 years of follow-up in patients treated with submucosal resection combined with outfracture.



  • Bipolar radiofrequency has been proven safe and effective in both adult and pediatric populations.



  • Long-term (2-year) follow-up of radiofrequency (RF) turbinate reduction for allergic and nonallergic inferior turbinate hypertrophy has shown improvement in olfaction, decreased nasal resistance and subjective improvement in nasal obstruction.



  • Long-term (10-year) follow-up of microdébrider reduction has shown symptom improvement in 93% of cases. Endoscopy, mucociliary clearance time, and anterior rhinometry remained improved over the long term.



  • Comparisons between bipolar radiofrequency ablation and microdébrider submucosal resection have shown improvement in symptoms with both techniques, with the microdébrider technique yielding greater improvement over a longer period of time.



Step 1





  • Under direct visualization, either with a nasal speculum or 0-degree endoscope, inject the inferior turbinate with 1% lidocaine with 1:100,000 epinephrine.



Step 2



Feb 1, 2019 | Posted by in OTOLARYNGOLOGY | Comments Off on Middle and Inferior Turbinates

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