The key to a successful septorhinoplasty includes an understanding of nasal anatomy and physiology. This allows the surgeon the ability to properly address both form and function during the operation. History and physical examination are paramount in diagnosing and subsequently treating the epicenter of obstruction, which is commonly found among the internal and external nasal valve, the septum, or the turbinates. Treatment of each of these areas is nuanced and multiple approaches are discussed to provide an understanding of the current surgical techniques that allow for excellent functional and cosmetic rhinoplasty results.
Key points
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Nasal obstruction is an important consideration in both functional and aesthetic septorhinoplasty.
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For a successful surgical correction of nasal obstruction, diagnosing the precise anatomic point of collapse is fundamental.
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Recognition of the nature and location of nasal valve, septal, and turbinate disorders allows adequate correction and acceptable functional results.
Introduction
Nasal obstruction is a common problem. Normal nasal breathing involves the interaction of static and dynamic forces, including the nasal septum, lateral nasal walls, and nasal mucosa. Although many patients who present for rhinoplasty evaluation have predominantly aesthetic concerns, many patients are also concerned for nasal airway obstruction. In addition, postoperative airway compromise can detract significantly from an otherwise good aesthetic surgical result. As such, preoperative analysis of the nasal airway is an imperative step in operative planning even if the patient does not necessarily raise concerns over this issue. Modern rhinoplasty techniques allow for success in both nasal aesthetics and function, improving the quality of life functionally and cosmetically as well as allowing for mutual satisfaction of patient and surgeon alike. It is therefore a paramount consideration in surgical planning. When evaluating patients with nasal obstruction, the most important variable of nasal airflow is the diameter of the nasal passage. The key to a successful surgical correction of nasal obstruction is diagnosing the precise anatomic point of collapse. Causes of nasal obstruction with particular relevance for rhinoplasty surgeons are discussed later.
Introduction
Nasal obstruction is a common problem. Normal nasal breathing involves the interaction of static and dynamic forces, including the nasal septum, lateral nasal walls, and nasal mucosa. Although many patients who present for rhinoplasty evaluation have predominantly aesthetic concerns, many patients are also concerned for nasal airway obstruction. In addition, postoperative airway compromise can detract significantly from an otherwise good aesthetic surgical result. As such, preoperative analysis of the nasal airway is an imperative step in operative planning even if the patient does not necessarily raise concerns over this issue. Modern rhinoplasty techniques allow for success in both nasal aesthetics and function, improving the quality of life functionally and cosmetically as well as allowing for mutual satisfaction of patient and surgeon alike. It is therefore a paramount consideration in surgical planning. When evaluating patients with nasal obstruction, the most important variable of nasal airflow is the diameter of the nasal passage. The key to a successful surgical correction of nasal obstruction is diagnosing the precise anatomic point of collapse. Causes of nasal obstruction with particular relevance for rhinoplasty surgeons are discussed later.
Anatomic consideration
Proper postoperative function of the inferior turbinates, septum, and nasal valves determines, to a large degree, the success of functional rhinoplasty. Although there are other anatomic aspects to consider, these structures largely contribute to the size and patency of the nasal airway. Constantian and Clardy performed nasal air flow measurements on patients with postrhinoplasty nasal obstruction and found septal deviation, internal nasal valve obstruction, and external nasal valve collapse to be the primary causes.
The Nasal Valves
The nasal valve area has been the subject of numerous studies because of its functional importance. It was first described by Mink in 1903, and in 1970 Bridger further described this area as the flow-limiting segment of the nasal airway. The nasal valve area represents the area bound by the septum, the caudal aspect of the upper lateral cartilages and lower lateral cartilages, the lateral nasal wall, the nasal floor, and sometimes the head of the inferior turbinate. The valves, classified as external and internal, represent the narrowest portion of the nasal airway and account for half the total nasal airway resistance. Distinguishing between the internal valve and the external nasal valve helps to direct treatment among the different regions of the nasal sidewall.
The External Nasal Valve
The external nasal valve is supported by the caudal aspect of the nasal side wall and is delineated by the nostril rim; it is referred to as the nasal inlet. It is defined medially by the medial crus of the lower lateral cartilage and inferiorly by the nasal spine and the soft tissues over the nasal floor. External nasal valve collapse is described as collapse of the alar margin of the nose on moderate to deep inspiration, caused by negative pressure during inspiration under the influence of Bernoulli forces. The collapse of the external nasal valve is most often seen in patients with narrow nostrils; an overprojected tip; and thin, weak sidewalls. It is often seen in patients with cephalically malpositioned lower lateral cartilage in whom the absence of cartilage support along the nostril rim leads to weakness of the sidewall. The external valve may also be narrow at rest, unrelated to dynamics of inspiration.
The Internal Nasal Valve
The internal nasal valve angle is the angle created by the junction of the caudal border of the upper lateral cartilage and the nasal septum ( Fig. 1 ). The valve angle measures 10° to 15°. However, the importance of this valve rests primarily with its area. The area of the internal nasal valve is the narrowest portion of the nasal airway and therefore it is the primary determinant of nasal air flow. Cole describes the 4 functional components of the internal nasal valve area as being the structural elements, which include the internal nasal valve angle and the bony pyriform aperture; and the mucovascular elements, which include the anterior head of the inferior turbinate and the erectile body of the septum. Internal nasal valve collapse is usually observed after previous reductive rhinoplasty or in patients with weakening of the supportive structures of the nose, such as the upper and lower lateral cartilages.
The Septum
The septum is a midline nasal structure. Posteriorly, the bony nasal septum is formed by the perpendicular plate of the ethmoid bone and the vomer. Anteriorly, the quadrangular cartilage forms the cartilaginous septum, which articulates with the upper lateral cartilages. Septal deviation off the midline can result in structural blockage of nasal air flow during inspiration or it may cause turbulent airflow. This condition can be congenital or a result of previous nasal trauma. Specifically for nasal valve surgery, the important areas of the nasal septum are the caudal aspect at the nasal vestibule (which would narrow the external valve) and the internal nasal valve area (which relates to Cottle area 2). Cottle’s subdivision of the nasal cavities in 5 areas, based on morphologic and rhinomanometric observations, provided a practical scheme that is still useful to understand the relationship between obstruction and anatomic considerations, thus benefiting modern understanding of functional nasal surgery. In addition, deflection of the posterior septum can result in significant narrowing of the nasal airway and should not be overlooked when evaluating for causes of nasal obstruction. Nasal septal perforations may also contribute to the sensation of nasal airway obstruction.
The Turbinates
The arteries of the nasal mucosa branch off to capillary vessels, which drain into the venous sinusoids of the erectile tissues of the mucosa. A major component of these erectile tissues contributes to the volume of the nasal mucosa; these are especially well developed at the interior part of the inferior turbinate and on the nasal septum. This expansile tissue can regulate nasal air flow because congestion of this entity can cause changes to the nasal cross-sectional area and resistance to airflow ; it is also a functional component of the nasal valve as described by Cole. Inferior turbinate hypertrophy is a common contributor to nasal obstruction, but the inferior turbinates are also an essential functional component of the nose and should be approached cautiously.
Physical examination
As with any preoperative planning, the history and physical examination are key to identifying the causes of nasal airway obstruction. Although most rhinoplasty planning is based on study of the standard preoperative photographic images (frontal, base, lateral, oblique), an anterior rhinoscopy with headlight allows visualization of the nasal septum and the inferior turbinate as well as any disorders associated with these structures, especially after the decongestion of nasal mucosa. Nasopharyngoscopy is often useful to further assess the disorders of the posterior septum, middle turbinate, middle meatus, nasopharynx, and all regions that are in limited view with anterior rhinoscopy. It is also extremely important, when surgery is considered, to identify all intranasal disorders, to determine the amount of cartilage available for grafting and to rule out tumors, perforations, or nasopharyngeal lesions that could contribute to the patient’s symptoms. Approaching surgery with the greatest possible amount of information can help ensure the best outcome.
An inspection of the base view of the nose yields important information. On base view, special attention should be given to triangularity and symmetry for sources of nasal obstruction as well as cosmesis. The nasal base should be configured as an isosceles triangle with a gently rounded apex at the nasal tip and subtle flaring of the alar sidewalls ( Fig. 2 ). The caudal septum may be seen protruding into one of the nostrils ( Fig. 3 ). The base view on normal breathing and deep inspiration can reveal collapse of the alar margin of the nose, which is diagnostic of external nasal valve collapse ( Fig. 4 ).
During physical examination, some patients report marked improvement in nasal obstruction when the nasal sidewall is distended with the wooden end of a cotton-tipped applicator or other device, or lateral retraction of the cheek. This maneuver, known as the Cottle maneuver, allows reliable identification of an internal nasal valve disorder and helps in identifying appropriate surgical candidates ( Fig. 5 ).
Objective obstruction measures include rhinomanometry and acoustic rhinometry. Rhinomanometry is the most commonly used objective test of the nasal airway. Although there are various methods of rhinomanometry distinguished by the varying placement of the pressure sensor, anterior active rhinometry is the most commonly used in the clinical setting. The purpose of this testing is to measure airflow as a function of air pressure for each nasal cavity separately. To isolate one nasal cavity, the contralateral naris is occluded with a pressure-sensing plug, and the nasal airflow through the unoccluded cavity is quantified by a flow sensor embedded in a tight-fitting face mask. Acoustic rhinometry, developed by Hilberg and colleagues in 1989, measures intranasal volume, the size and location of minimal cross-sectional area, and dimensional changes using sound reflections created by a sound generator and microphone coupled to a patient’s nose with a flexible silicon tube. Despite considerable interest and research, use of these objective tests is limited and rhinoplasty surgeons instead favor patient-reported subjective symptoms as well as the validated Nasal Obstruction Symptom Evaluation (NOSE) questionnaire as subjective assessments of patient breathing. Previously published research validates the practice of relying on patient subjective assessment of breathing along with the clinician’s physical examination in determining nasal obstruction and surgical candidacy.
Once the history and physical examination have revealed the potential sources of nasal obstruction, operative planning can begin.
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