Summary

Functional nasal surgery is a gratifying ear, nose, and throat (ENT) subspecialty. Suboptimal outcomes after such surgery are nevertheless too often a source of patient and surgeon dissatisfaction. Comprehensive management of nasal obstruction necessitates a thorough understanding of nasal physiopathology, in addition to experience and humility. We hope this chapter will help readers improve their knowledge in identifying the anatomical sources of patient symptoms in addition to providing validated surgical techniques.

Introduction

Nasal obstruction is a common symptom associated with a major decrease in disease-specific quality of life and is known to have a high impact on public health status.

It is present in nasal inflammatory disease and structural deformities. The effect of structural deformity on sinus inflammatory status has been shown to be related to the same degree as inflammatory sinus disease affecting lower airway function.1,2

First reports of nasal reconstruction date from 600 BC.3 Recently, extensive research has concentrated on the understanding of nasal airflow perception; still, rhinologists are unsure about how to quantify nasal airflow function with a reproducible, cost-effective, and easy-to-use test.4 Subjective nasal obstruction scales have been developed and are currently used to monitor outcomes from surgical intervention.

Refinements in surgical techniques have evolved in restoring nasal airway function and are supported by constant monitoring of outcome measures. The main challenge is to determine when and to what extent structural anomalies relate to nasal obstruction.

In this chapter, we discuss the frequent structural anomalies the rhinologist and rhinoplastic surgeon will face, and, where possible, we have attempted to provide up-to-date evidence-based clinical guidance.

Relevant Nasal Anatomy

Paired nasal bones are situated in the middle of the face. They are connected superiorly to the frontal bones with the frontonasal suture (nasion) and laterally to the ascending process of the maxillary bone with the frontomaxillary suture. Their length, extending from the nasion to the osteocartilaginous junction (rhinion), represents the upper third of the nose ( Figs. 26.1, 26.2, 26.3, and 26.4 ).

The septum is made of bony and cartilaginous structures. The perpendicular plate of the ethmoid, posterosuperiorly based, connects inferiorly with the vomer, whose posterior aspect forms the medial wall of the choanae. The vomer is inferiorly connected to the palatine bone posteriorly and to the maxillary crest anteriorly.

The cartilaginous part of the septum, the quadrangular cartilage, lies on the maxillary crest and connects with the vomer posteroinferiorly and the perpendicular plate of the ethmoid posterosuperiorly. Its dorsal edge extends from the osteocartilaginous junction to the anterior septal angle, forming part of the middle and lower thirds of the nose. Its caudal free edge extends from the anterior septal angle to the posterior septal angle resting on the anterior nasal spine. The caudal septum is part of the columella ( Fig. 26.5 ).

The upper cartilaginous vault corresponds to the middle third of the nose. It is made of the dorsal septum flanked by the trapezoid-shaped upper lateral cartilage. These are firmly attached superiorly to the deep aspect of the nasal bones, where they underlie variably. Stability is provided by the continuity of the perichondrium of the upper lateral cartilage with the periosteum of the nasal bones. In the midline, each section of upper lateral cartilage is intimately fixed to the quadrangular septum and to the contralateral upper lateral cartilage by a continuous perichondrial sheet. The angle formed by the upper lateral cartilage and the septum is between 10 and 15 degrees in the leptorhinne nose. Laterally, the upper lateral cartilage is connected to the piriform aperture by connective tissue containing sesamoid cartilage.5

The lower cartilaginous vault corresponds to the lower third of the nose. It is made of the caudal septum and the paired sections of lower lateral cartilage. The lower lateral cartilage has a medial crus, forming part of the columella; an intermediate crus, corresponding to the dome; and a lateral crus that extends laterally, parallel to the alar rim, then curves cranially toward the pirifom aperture. The shape and the relation of the lower lateral cartilage to the septum account for a major role in supporting the external nasal valve and the tip ( Figs. 26.6 and 26.7 ; see also Figs. 26.4 and 26.5 ).

Tip Support

Strong and durable tip support is fundamental in functional rhinoplasty. Different tip support theories have been proposed in the literature. Refinements and new concepts have occurred over the past 50 years due to the experience gained after careful analysis of rhinoplasty outcomes. We review in this section the concepts that are of importance to appropriately anticipated outcomes.

The tripod concept presented by Anderson6,7 in the late 1960s has received strong support. Its application to tip surgery has proven good predictability in tip modification. Rotation, derotation, projection, and deprojection are well illustrated by the tripod concept. The tripod is formed by the medial crura united as the medial leg resting on the anterior nasal spine and the two lateral crura forming each lateral leg resting on the piriform aperture (see also Chapters 23 and 25, Figs. 23.8 and 25.19 ). Nevertheless, some authors have argued that the lateral crura do not have contact with the piriform aperture and that predictability is reliable in the leptorhinne nose only.

Janeke and Wright8 studied the normal anatomy of tip support in view of frequently observed postoperative sagging of the tip of the nose after rhinoplasty. Cadaveric dissection found consistent findings explaining nasal tip support. The authors stated that the intercartilaginous ligament, attaching the caudal aspect of the upper lateral cartilage to the cephalic border of the lateral crus, is a major element of tip support. The interdigitation between the upper lateral cartilage and the lateral crus is referred to as the scroll area because of the outward curling of the upper lateral cartilage. In fact, the caudal aspect of the upper lateral cartilage can take different shapes, and the most common configuration is the overlapping of the lateral crus over the upper lateral cartilage. Janeke and Wright mentioned the lateral sesamoid complex cartilage, which provides support to the lateral crura in the region called the nasal hinge. The junction of the medial crura to the septum and the interdomal sling are the two other mechanisms described in their study.

Tardy9 presented major and minor mechanisms for tip support. He also stated that occasionally these minor mechanisms may in fact be of significant importance according to interindividual variation. Tip recoil with digital palpation was mentioned to be of value for assessing tip support. Major mechanisms are size, shape, and resilience of the medial and lateral crura, medial crural footplate attachment to the caudal border of the quadrangular septum, and attachment of the caudal border of the upper to lower lateral cartilage. Minor mechanisms are the interdomal ligament, cartilaginous dorsal septum, membranous septum, lateral sesamoid complex, anterior nasal spine, and attachment of the lower lateral cartilage to the overlying skin–soft tissue envelope (S-STE).

More recently, Adamson et al10 presented the M-Arch model, which is an extension of the tripod concept. It states that the curvature of the lower lateral cartilage creates a tension in the lower lateral crura, like a spring, which projects the tip dorsally and inferiorly. The medial crura counteract this force with an anterior and superior thrust. The M-Arch model emphasizes the dynamics of the lower lateral cartilage and considers the overall length of each section of lower lateral cartilage as one arch, which can be altered at any point according to the desired goal.

Westreich and Lawson11 built on the cantilevered spring theory, describing the paired lower lateral cartilages as having a single point of fixation around which the elastic tripod will rotate. Downward forces equal the cantilevered spring potential energy added to the other tip support element:

where PE = potential energy, E = elastic modulus of the spring, w = width, h = height, l = length, and x = displacement of the spring.

Displacement of the cantilever pivot point explains different modifications among different types of nose. For example, if the pivot point is at the anterior septal angle, reduction of the anterior septal angle position will have a dramatic effect in deprojecting the nose, whereas if the pivot point is at the base of the columella, deprojection will be minimal. Westreich and Lawson note the importance of the surrounding forces in establishing the new isometric equilibrium point after nasal structure alteration. This bio-mechanical theory is very seductive in explaining unwanted outcomes, such as tip ptosis and pollybeak deformity, after rhinoplasty. The cantilever dynamic concept also provides an answer to different techniques in ethnic rhinoplasty.

Internal Nasal Valve

The internal nasal valve is the minimum cross-section area (MCA) of the nose, offering the highest resistance to air entry in the nose. Its boundaries are the septum medially, the upper lateral cartilage superolaterally, the head of the inferior turbinate inferolaterally, and the floor of the nose ( Fig. 26.8 ).

The upper lateral cartilage is denuded of muscle attachments.5 Its stability relies on the intrinsic strength of the cartilage added to the rigidity of the strong continuous perichondrial connection to nasal bones and septum.

Evaluation of a patient with nasal obstruction should always address recognition of nasal valve dysfunction. Endoscopic assessment of the external and internal valve (see Video 32, Alar Collapse ), Glatzel plate test (observing the condensation of exhaled air on a cold metal surface), static and dynamic recognition of nasal valve collapse, and modified Cottle test (assessing objective and subjective nasal patency after correction of nasal valve collapse) should be performed ( Fig. 26.9 ).

Acoustic rhinometry is a useful research adjunct, as this gives surface measurements before and after topical decongestion, helping the clinician to determine the contribution of the structural deformity to the symptoms of a patient. The nasal MCA was found to be located at 2.35 cm from the opening of the nostril and measures 0.62 cm² using acoustic rhinometry in a healthy volunteer.12,13

Clinical relevance of acoustic rhinometry is discussed later in this chapter.

External Nasal Valve

The external nasal valve corresponds to the opening of the nose or nasal vestibules ( Fig. 26.10 ). The nasal vestibule is bordered laterally by the alar sidewalls, medially by the columella, and inferiorly by the nasal sills. In a craniocaudal direction, the external nasal valve extends along the width of the lower lateral cartilage, accounting for 1 cm. The triangular shape of the nose seen in a basal view relates to the 45-degree angle between the alar sidewall and the columella.

The alar sidewall support relies on the lower lateral cartilage. Nevertheless the lateral aspect of the alar sidewall is deprived of cartilage support, as the lower lateral cartilage curves cranially and consists of fibrous tissue. The dilator naris muscle originates from the lower lateral cartilage and attaches to the fibrous tissue of the alar rim, providing support. The apicis nasi muscle can vary in degree of development and attaches to the lower lateral cartilage. The alar part of the nasalis muscle is attached to the sesamoid cartilage of the alar sidewall, preventing alar collapse during nasal breathing. Medially, the depressor septi muscle inserts into the medial crus of the lower lateral cartilage.5

Etiology of Nasal Obstruction

The differential diagnosis of nasal obstruction is wide. It can be separated into congenital and acquired causes and further subdivided into structural deformities (Table 26.1). Structural deformities include congenital septal deviation; posttraumatic nasal deformity; inferior turbinate hypertrophy; and valve collapse that is iatrogenic or due to intrinsic weakness, the aging process, or the presence of facial palsy.

Septal deviation has been reported in up to 80% of the general population and 90% of patients attending an ENT clinic.14,15 Combined cartilaginous and bony septum deviation is more frequent in newborns delivered vaginally, especially in the occipitoposterior position, than in newborns delivered by cesarean section. The maxillary molding theory explains that, during intrauterine life, the facial structures of the fetus are exposed to pressure, which can compress the septum against the solid skull base. This can result in a C- or S-shaped deformity of the septum and could even account for maxillary bone displacement leading to malocclusion.

Aging of the Nose

An increasing number of older people seek opinion regarding nasal blockage symptoms. Regardless of the mucosal pathology associated with the elderly, age-related change in the nose is now recognized as a true entity.

There are essentially three major changes: loss of tip support, internal valve collapse, and external valve collapse.16

An aged nose typically displays an increase in total nasal length, with alteration of facial proportions, and a ptotic tip due to lack of tip support ( Figs. 26.11 and 26.12 ). This is attributed to the loss of the previously mentioned tip support elements. Fibrous attachments between the upper and lower lateral cartilages become loose, and cartilage provides weaker support. The skin becomes thinner in the upper third of the nose, more sebaceous in the lower third, and loses its previous leveling property. Alveolar bone resorption and maxillary hypoplasia contribute to a sunken anterior nasal spine.

Also, intrinsic weakness of the cartilage occurs, leading to alar collapse.

Cartilage Considerations

Nasal cartilage is hyaline. Chondrocytes are embedded in an extracellular matrix made of collagen type II and a high content of proteoglycan aggrecan. Proteoglycan aggregates with hyaluronan and link protein and provides the osmotic property of the cartilage to resist compressive loads.

Most of the work on nasal cartilage senescence is in osteoarthritis-based research. Chondrocyte senescence is not represented by a reduction in mitotic rate due to the absence of cell division of a chondrocyte over a lifetime. Instead, chondrocyte senescence exhibits a change in phenotype expression, resulting in an imbalance between decreased anabolic and increased catabolic activity. Development of the senescent secretory phenotype alters the production of matrix proteins and may explain the increase in type II collagen degradation product in the urine of healthy adults over age 50. Also, aging of the cartilage matrix, such as changes in aggrecan nature and accumulation of advanced glycation end products, accounts for some modification in cartilage biomechanical property resulting in loss of resiliency and increased stiffness.17,18

One study published in 200319 looked at the composition of human septal cartilage. Harvesting was performed from the inferior region of the nasal septum. Each wet gram of cartilage contained 77.7% of water, 7.7% of collagen, 2.9% of sulfated glycosaminoglycans (sGAG), and 24.9 million cells. No statistically significant gender difference in the quantity of cartilage constituent was found. A strong tendency toward a reduction was found in cellularity and sGAG content with advancing age. The impact of those age-related trends is not established. Nevertheless, those findings may be an indicator of decreased synthetic capacity or accelerated catabolic activity in chondrocytes of advanced age.

The unpredictable availability of nasal septal cartilage in revision septorhinoplasty procedures has led to research in engineering cartilage. The standard value of cartilage elastic modulus has been investigated to provide comparison to bioengineered cartilage. Richmond et al20 demonstrated that human nasal cartilage had anisotropic properties and that vertical orientation had higher stiffness of 0.71 MPa (megapascals). Lower values were found in comparison to the study of Westreich et al;21 this was attributed to the preparation techniques. In vivo analysis, as performed by Westreich et al, revealed inconsistent value but showed that preservation of the outer layer of cartilage would retain a higher stiffness. In order of decreasing stiffness value were septal cartilage, followed by upper lateral cartilage, auricular cartilage, and lower lateral cartilage.

During a septorhinoplasty procedure, the surgeon assesses the stiffness of the available cartilage and decides whether the material will be of good use. An interesting study by Zemek et al22 investigated with elastomer specimens used as mechanical phantoms the minimal required stiffness for reconstruction of an L-strut, columella strut, and alar grafts. They found, with reproducibility, threshold values of 0.56, 0.59, and 0.49 MPa for the columella strut, L-strut, and alar grafts, respectively.

Investigations

Perception of nasal airflow is not fully understood. It is believed that some cold and tactile receptors, located in the nasal vestibule and in the nasal cavity, are mediated through branches of the trigeminal nerve and are responsible for the sensation of nasal airflow.23,24 Menthol inhalation induces an increase in subjective nasal patency perception with no consistent effect on nasal resistance.25 Objective assessment tests have been developed to understand nasal physiology and have then been applied to clinical situations to quantify the nasal airflow obstruction (Table 26.2).

In 1894 Zwaardemaker published a study on hygrometry. This consisted of measuring the diameter of the fog produced by each nostril.

Since then, inspiratory nasal peak flow, acoustic rhinometry, rhinomanometry, and software (e.g., Odiosoft-Rhino; Odiosoft Medical Software, Istanbul, Turkey) have been developed. They are commonly used in research settings to anticipate the therapeutic effect of a maneuver on nasal airflow. Variable correlation with patients’ symptoms has not led to widespread use in clinical settings. Their use, indications, and limitations are discussed in more detail in Chapter 6.

Disease-specific questionnaires have been developed to measure improvement in a patient′s symptoms after a therapeutic measure. The visual analogue scale (VAS) is easy to use. Nevertheless, it does not detail other parameters associated with quality of life alteration. The Nasal Obstruction Symptoms Evaluation (NOSE) questionnaire has been validated as a disease-specific measure of quality of life modification for patients suffering from nasal obstruction.26 It is brief, valid, reliable, and responsive. It is currently the most widely used test in functional rhinoplasty studies. The Sino-nasal Outcome Test 22 (SNOT-22), which is commonly used to assess patients with chronic rhinosinusitis, has also proved reliable on nasal obstruction assessment27 and may be a useful test for all patients in a rhinology clinic. The nasal Appearance and Function Evaluation Questionnaire (NAFEQ) has the advantage of addressing functional items as well as appearance perception.28 The rhinoplasty Outcome Evaluation (ROE) is a purely cosmetic questionnaire developed for cosmetic change assessment and has also been validated.29 For more information on these and other patient-reported outcome measures, see Chapter 9.

Video endoscopic photodocumentation (see Video 32, Alar Collapse ) is a useful adjunct to monitor mucosal inflammatory status and internal valve angle. Its main advantage is the absence of distortion of the anatomy during the assessment, but it offers no standardized reading scale.30,31

Imaging techniques, such as computed tomography(CT) and magnetic resonance imaging (MRI), have been shown to correlate well with acoustic rhinometry findings.32,33 Their clinical use is debatable, however, as a CT scan involves irradiation, and MRI is expensive.

Structural Causes of Nasal Obstruction

Nasal obstruction is associated with multiple pathologies, which are discussed in detail in other chapters. Correctly identifying chronic inflammation of nasal mucosa, especially in the presence of a structural anomaly, should not be overlooked. Also, a systematic review of the literature on the potential role of septal deviation on rhinosinusitis revealed a statistically robust association between rhinosinusitis and septal deviation, especially with a septal deviation angle > 10 degrees.1 Therefore, appropriate treatment should be initiated before considering functional surgery.

Six key areas must be examined in looking for underlying structural anomalies associated with nasal obstruction:

1. 
   

   Septum

   
   
2. 
   

   Paired nasal bones

   
   
3. 
   

   Inferior turbinate

   
   
4. 
   

   Position of the tip

   
   
5. 
   

   Internal valve

   
   
6. 
   

   External nasal valve

The patient history should highlight previous nasal fracture and previous nasal surgery, including cosmetic rhinoplasty.

Examination should focus on identifying the underlying structural deformities causing nasal obstruction. The position of the nasal bones should be noted. Severe septal deviation can be the source of nasal obstruction. Glatzel′s mirror test will give some objective evidence of differential nasal airflow.

Static and dynamic internal valve collapse must be actively identified. Notched alar rims and an hourglass appearance of the nasal tip are suggestive of external valve dysfunction (see Fig. 26.12 ). Tip projection, tip recoil, and nasolabial angle are also of fundamental value in examining external valve dysfunction. Dynamic collapse of the external valve seen on inspiration at rest is a strong sign of valve collapse. The Bernoulli principle, which states that high velocity of air passing through the nasal passage creates a vacuum effect, explains the collapse. The reason for the collapse is poor support of the lateral crus of the lower lateral cartilage that occurs after excessive cephalic trim or in a situation of low intrinsic strength of the cartilage. An inverted V deformity is often associated with previous rhinoplasty. This consists of insufficient support of the midvault due to either absence of reconstruction or resorption of previously inserted grafts. The modified Cottle test, consisting of intranasal insertion of a cotton bud at the point of the nasal valve weakness, is useful in evaluating the realistic benefit of corrective valve procedures. Endoscopic evaluation of the internal nasal valve is helpful in determining the presence of a narrow angle between the upper lateral cartilage and septum. Outcomes of a specific nasal valve procedure are impossible to assess, as multiple simultaneous modifications of the nasal valves and an associated septoplasty are usually performed at the time of surgery. A recent systematic review of the literature on nasal valve surgery isolated 44 articles on the benefit of nasal valve repair.34 Thirty-three reviewed studies mentioned adjunctive concomitant procedures, and 11 studies purely assessed nasal valve correction. Forty-two articles were level IV evidence, and 2 were level IIb. Outcome measurements differed between studies. All studies reported improvement ranging from 100 to 65%.

Additionally, the revision septoplasty rate was shown to be associated in 51% of cases with a dysfunction of the nasal valve warranting surgery, whereas only 4% of the patients who had septoplasty with concomitant nasal valve surgery needed revision surgery for nasal obstruction.35

Assessment of the septum requires a thorough examination, locating with precision the position and extent of the septal deviation. Six septal anomalies are commonly described ( Fig. 26.13 ):

1. 
   

   Septal tilt

   
   
2. 
   

   C-shaped deviation, anteroposterior plane

   
   
3. 
   

   C-shaped deviation, dorsoventral (cephalocaudal) plane

   
   
4. 
   

   S-shaped deviation, anteroposterior plane

   
   
5. 
   

   S-shaped deviation, dorsoventral (cephalocaudal) plane36

   
   
6. 
   

   Isolated spur

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