The nasal airway is of paramount importance to the astute rhinoplasty surgeon. Often, great aesthetic results are combined with poor functional outcomes, leading to dissatisfaction and the need for further intervention. This problem is curtailed by careful consideration and analysis of the function of the nose as well as its aesthetic value. Even well-experienced surgeons face this problem in a significant number of patients. In the hands of the less-experienced surgeon eager to only please the patient’s aesthetic needs, this may be a more common issue. This is complicated by the fact that minor intranasal pathologic conditions that were not clinically significant preoperatively may become distressing and a focal point of complaints in the postoperative setting. As such, surgeons must diagnose both cosmetic and functional issues well in advance so as to ensure a favorable outcome.
Nasal Anatomy and Function
One may assume the anatomy of this area to be simple, but there are some nuances that explain our less than satisfactory outcomes or complications.
The septum is composed of several components, both bony and cartilaginous. Maxillary, palatine, vomerine, and ethmoid bones contribute to the bony septum. However, the anterior nasal septum is cartilaginous, which allows for the most protruding portion of the nose to be flexible. The cartilaginous septum is attached superiorly to the perpendicular plate of the ethmoid, the bony groove on the undersurface of the nasal bones, and the upper lateral cartilages; these structures are held together by the continuity of the perichondrium and periosteum. Anteriorly fibrous attachments to the medial crura of the lower lateral cartilages determine the integrity of the tip. Inferiorly, the cartilaginous and bony septum lie in the bony groove of the maxillary crest via dense fibrous connective tissue. Embryologically, the cartilaginous septum develops from the perpendicular plate of the ethmoid, yet it remains nonossified. As such, the overlying perichondrium is contiguous with the periosteum of the perpendicular plate. While the vomer has a different embryologic origin and maintains its own periosteum, it is separated at the transition point with the septum of ethmoid bone origin. This seemingly innocuous fact is an important one in that elevation of the mucoperichondrium at the juncture of the perpendicular plate of ethmoid is rarely met with resistance or perforation. The majority of perforations occur at the junction of the cartilage to the vomer due to the noncontinuous covering.
The flow of air in the nasal passage follows the basic tenets of physics and Ohm’s law, whereby gases move when there is a pressure gradient, and this flow can be hampered by friction. In laminar flow in a passageway, the fluid in the center has the greatest motion while that which is in contact with the sidewalls is hampered and moves slowly. Turbulent flow results from random, nonlinear motion. In the nasal cavity, laminar flow is of utmost importance because it allows for appropriate humidification and proper mucociliary flow of mucus, while turbulence creates more friction and impairs both functions. The septum helps ensure a laminar flow pattern.
The three paired turbinates are located on the lateral nasal wall. The superior and middle turbinates arise from the ethmoid bone, whereas the inferior turbinates are made of independent bony structure. Covered by both respiratory and olfactory epithelium, the superior turbinate is located high in the nasal vault and usually arises from the cribriform plate of the ethmoid bone. The middle turbinate has a less consistent site of origin and could arise from the cribriform plate, the lamina papyracea, or the uncinate process in some cases.
The inferior turbinate bone arises on the inferior portion of the lateral nasal walls. The bone itself is penetrated heavily by vascular channels, which supply the overlying respiratory epithelium. The lacrimal duct drains into the nose just lateral to the inferior-anterior portion of the inferior turbinate.
The anterior tip of the turbinates not only directs the air along the passageway to the nasopharynx in a laminar fashion but also acts to deflect some of the air upward towards the olfactory mucosa, thus facilitating olfaction. The nasal cycle , a periodic alternating engorgement and enlargement of the inferior turbinates on one side accompanied by contralateral turbinate shrinkage, occurs in about 85% of people. The cycle takes anywhere between 3 to 4 hours to complete, and the total airflow throughout the cycle remain constant. Often, in the postoperative setting, patients complain of alternating nasal obstruction, which is in effect a heightened awareness of the cycle due to surgery and resultant hypersensitivity.
Nasal Airway Obstruction
There are several components that contribute to nasal airway obstruction. In the pediatric population, congenital anatomic contributions are significant, with adenoid hypertrophy and choanal atresia being the most common. For the adult population, in addition to anatomic considerations, such as septal deviation, septal spurs, and turbinate hypertrophy, the differential diagnoses of tumors and polyps need to be entertained and excluded. A list of nasal airway obstruction components is given in Table 35-1 .
|Turbinates||Narrowed pyriform aperture|
|External nasal valve||Stenosis|
|Internal nasal valve||Choanal atresia|
|Allergic rhinitis||Adenoid hypertrophy|
Using a headlight, nasal speculum, and an optional endoscope, the surgeon needs to perform diagnostic endoscopy of the nasal vault and nasopharynx. This allows full evaluation of these regions and exclusion of any nonanatomic causes of nasal airway obstruction. Specifically, it allows diagnosis of any visible polyps or malignancies. If purulent discharge or middle meatus obstruction is identified, sinusitis is likely and appropriate treatment with antibiotics is indicated. If an allergic component is considered, nasal steroid sprays, nonsedating antihistamines, and decongestants are first-line treatment. Allergy testing and desensitization should also be considered. Rhinitis medicamentosum must be ruled out and treated in individuals who chronically use oxymetazoline (Afrin), phenylephrine (Neo-Synephrine), and/or xylometazoline (Otrivin or Inspire). If complete nasal deviation is noted, coexistent pathology needs to be ruled out with computed tomography.
Once adequate examination and workup have been completed and the appropriate diagnosis has been made, attention is then directed to treating the underlying etiology for the patient’s nasal airway obstruction. Allergic rhinitis, chronic rhinosinusitis, and turbinate hypertrophy must be initially treated medically. Assuming that all other diagnoses have been ruled out and the patient is diagnosed with only septal deviation as the cause of the nasal aiway obstruction, the decision to perform a septoplasty is entertained. However, the contribution of the nasal turbinates should not be overlooked.
Prior to performing surgery, a thorough history needs to be taken, specifically addressing any coagulopathies, medication allergies, or coexisting medical conditions that can be medically optimized preoperatively. Additionally, patients with nasal polyps may be administered preoperative steroids to facilitate intraoperative bleeding and any associated asthma.
The facial skin is prepared with povidine-iodine or chlorhexidine solution and draped to expose the face. Cotton pledgets soaked with neosynephrine and cocaine are inserted into the nares bilaterally to help achieve vasoconstriction. Using a small syringe and 27-gauge needle, 1% lidocaine with 1 : 100,000 epinephrine is injected to locally anesthetize the region. Local anesthesia is infiltrated externally if the patient is undergoing simultaneous rhinoplasty or internal/external valve reconstruction. The anesthetic is injected into the intercartilaginous region to block the external nasal nerve bilaterally, the edge of the piriform aperture to get the branches of the infrorbital nerve to the nasal ala, and the junction of the caudal septum and columella. Intranasally, it is injected between the perichondrium and the septal cartilage and between the mucoperiosteum and the bone to help achieve anesthesia, hydrodissect the surgical plane, and increase the soft tissue bulk to avoid inadvertent perforation of the mucoperichondrial flap. The inferior turbinates are also anesthetized bilaterally as needed. In the event of a severely deviated septum that precludes injection of the local anesthetic, a long nasal speculum is placed into the narrowed nasal cavity and deflected toward the contralateral side to allow for improved exposure.
In performing a septoplasty, there are two incisions that are typically used—hemitransfixion or Killian—and a decision as to which one to use is made by the surgeon ( Figure 35-1 ). This decision is based on several factors. The hemitransfixion incision allows adequate exposure to address the septal deviation in both anterior and posterior regions. Furthermore, it allows placement of endonasal spreader grafts by having access to the entire length of the upper lateral cartilage. The hemitransfixion incision is placed in the most caudal aspect of the cartilaginous septum.