Work-Up And Evaluation Of Patients With Nasal Obstruction

Julie L. Wei, MD, William J. Remington, MD, and David A. Sherris, MD

Although the human nose appears to func­tion simply as a conduit for airflow and a platform for supporting eyeglasses, its many functions are exquisitely designed and are vital for both good physical and mental health. The four main functions of the nose are (1) respiration, (2) olfaction, (3) defense, and (4) cosmesis. Respiratory functions in­clude air transport, humidification, and war­ming to maximize oxygen and carbon dioxide exchange in the lungs. The importance of olfaction is perhaps best appreciated by real­izing the unpleasant effects of anosmia, like the inability to enjoy the smell of food and secondary decrease in both taste and appetite. In the defense mode, nasal mucosa both re-moves offending antigens through ciliary ac­tivity and acts as an interface between our immune system and the outside world. Fi­nally, cosmesis is by no means the least important of the nasal functions. Noses come in a variety of shapes and sizes, and not only can a nose reflect one's personal and even cultural heritage, but it plays a signifi­cant role in defining individual facial charac­teristics. Any gross deformity or asymmetry can at its worst affect one's self-esteem or confidence.

Both structural abnormalities and pathologic abnormalities can easily disrupt one or more of the nasal functions. Because nasal obstruction is a common complaint, it is useful to establish a comprehensive list of differential diagnoses to facilitate effective treatment. Causes of nasal obstruction include the following:

• Structural
• Septal abnormalities septal deviation impaction
• valve pathology perforation
• hematoma
• abscess
• Valve abnormalities alar collapse
• scar, adhesion, synechiae
• caudal end deviation Choanal atresia
• Congenital
• facial asymmetry Concha bullosa Foreign Body
• rhinolith
• organic, inorganic
• Mucosal Infectious viral
• bacterial fungal Rhinitis
• allergic vasomotor
• pregnancy
• medicamentosa
• atrophic menses Systemic diseases
• cystic fibrosis
• hypothyroidism
• dysgammaglobulinemia
• Wegener's granulomatosis
• Polyposis
• Turbinate hypertrophy

Benign and malignant nasal masses include the following:

• Benign Neoplasms Epithelial
• squamous papilloma inverting papilloma adenoma
• pleomorphic adenoma Soft tissue tumors
• fibrous histiocytoma hemangioma
• hemangiopericytoma neurofibroma
• neurilemmoma
• myxoma
• Bone and cartilage tumors ossifying fibroma chondroma
• osteoma
• Lymphoid and hematopoietic tumors plasmacytoma
• malignant lymphoma Miscellaneous tumors meningioma
• odontogenic tumors teratoma
• Secondary invaders craniopharyngioma chordoma
• nasopharyngeal carcinoma
• juvenile angiofibroma pituitary adenoma
• Benign Masses Encephalocele Adenoid hypertrophy
• Nasal gliomas Antrochoanal polyp
• Encephalocele Malignant Neoplasms
• Epithelial
• squamous cell carcinoma
• verrucous carcinoma
• spindle cell carcinoma
• transitional cell carcinoma
• basal cell carcinoma
• adenocarcinoma
• papillary adenocarcinoma
• sessile adenocarcinoma alveolar-mucoid adenocarcinoma colonic adenocarcinoma
• mucinous adenocarcinoma undifferentiated carcinoma
• Soft tissue tumors
• malignant hemangiopericytoma fibrosarcoma
• rhabdomyosarcoma
• neurogenic sarcoma
• malignant fibrous histiocytoma angiosarcoma
• Bone and cartilage tumors
• chondrosarcoma
• osteosarcoma Miscellaneous tumors
• malignant melanoma esthesioneuroblastoma
• Nasopharyngeal carcinoma
• squamous cell carcinoma
• lymphomas miscellaneous
• plasma cell myeloma
• rhabdomyosarcoma
• adenocarcinoma
• cylindroma melanoma fibrosarcoma

In addition to structural pathology, mucosal pathology, and nasal masses, nasal obstruction may be physiologic. One must understand the intimate relationships between the anatomy, physiology, and pathology of the nose to plan appropriate treatment for nasal obstruction.

PERTINENT NASAL ANATOMY

The nasal septum and nasal valve area are especially relevant to the regulation of nasal airflow and airway resistance. The septum is composed of the vomer, the perpendicular plate of the ethmoid bone, and the quadrangu­lar cartilage. There are five designated areas of the septum (Fig. 1), and deviation in any area may result in turbulent airflow and nasal obstruction if severe enough.

In the leptorrhine nose, the nasal valve area and angle are especially important in nasal airflow. The valve area is a three-dimensional structure bounded by the nasal septum medially, the lateral nasal wall to the bony point of the pyriform aperture laterally, the caudal end of the upper lateral cartilage superiorly, and the floor of the nose inferiorly. The head of the inferior turbinate contributes to the lateral aspect of the nasal valve area (Fig. 2). The nasal valve area has been calculated to be approximately 55 to 64 mm2.19 The nasal valve angle is the cleft formed by the septum and the caudal end of the upper lateral carti­lage. The nasal valve angle is normally 10 to 15 degrees. Any pathology in the upper lateral cartilage, septum, or mucocutaneous soft tissue, such as adhesions and scar, cause pathol­ogy in the nasal valve area or angle. Other terms for the nasal valve include the Iiminal valve, ostium internum, liminal chink, and flow-limiting segment.

Figure 1. Areas of the nose. 1, Vestibule; 2, nasal valve area; 3, attic; 4, anterior turbinate area; and 5, posterior turbinate area. (By permission of the Mayo Foundation.)

 

Figure 2. Clinical view of the nasal valve. This area is bounded by the nasal septum medially, the caudal end of the upper lateral cartilage superiorly, the lateral nasal wall to the bony point of the pyriform aperture laterally, and the floor of the nose inferiorly. (By permission of the Mayo Foundation.)

The nasal valve accounts for half of the total nasal resistance and is the most influential in-flow regulator of the nose.'° Air accelerates and changes from laminar to turbulent flow as it traverses the nasal valve, and it is the turbulent flow that allows maximal humidification to oc­cur. Once beyond the nasal valve, the septal valve becomes the next regulator of airflow. This valve is formed by the erectile mucosa of the middle turbinate and the septum. This valve further disperses air throughout the na­sal cavity. As maximal inhalation occurs, re­sulting in high inspirational flow rates, the alacollapses and prevents further airflow. The di­lator naris muscle opposes alar collapse by di­lating the nasal ala, thereby decreasing nasal resistance and increasing nasal airflow.

Finally, external nasal tip support and tissue stiffness are important to nasal airway func­tion. The ptotic tip, or excessively weak or ov­erresected lower lateral cartilage, can contrib­ute to nasal airway obstruction. Of course, the severely deviated external nose can be appreci­ated on observation and contributes to struc­tural airway obstruction.

NASAL PHYSIOLOGY

The nasal cycle is a natural phenomenon during which each side of the nose undergoes an alternating cycle of congestion and decon­gestion. This results from intermittent en­gorgement of the venous sinusoids and vascu­lar spaces in the mucosal lining. Hasegawa and Kern" demonstrated 72% of study subjects had clearly defined nasal cycle, with duration between 60 minutes and 6 hours. Whereas ap­proximately 80% of the population undergoes the nasal cycle, one normally does not com­plain of the subjective sensation of nasal ob­struction because the total nasal airway resis­tance remains steady and always lower than either uninasal resistance."

Nasal resistance is modified and controlled physiologically by the erectile tissues of the mucosa, because the rich capillary networks and venous sinusoids can engorge and limit airflow. The parasympathetic system controls the congestion and increased nasal secretion by vasodilatation of the sinusoids and capillar­ies in the mucosa, whereas the sympathetic system provides a steady vasoconstrictor tone. The sympathetic system enables vasoconstric­tion via a-adrenergic receptors. Thus, sympa­thomimetic drugs, such as topical intranasal ephedrine, may relieve nasal obstruction. It is through the engorgement of the mucosa that several endocrine disorders as well as physio­logic states like pregnancy and menses in women cause nasal obstruction. Several biochemical mediators and neurotransmitters have been identified, but their direct effect on human nasal physiology is unclear.

Structural Pathology
Congenital abnormalities, such as arrhinia (nasal aplasia) or gross craniofacial anoma­lies involving abnormal nasal structure, are readily identifiable. Bilateral choanal atresia tends to present at birth with difficulty breath­ing. Unilateral choanal atresia may go undiag­nosed until later in childhood. Septal deviation and valvular pathology can be significant con­tributors to nasal obstruction. Specific valve pathology may involve any of the com­ponent of the nasal valve, namely the septum, the mucocutaneous tissue, and the upper lat­eral cartilage (Fig. 3). The upper lateral carti­lage at the junction with the cartilaginous sep­tum may be twisted, concave secondary to weakness or prior trauma, thickened, de­flected, or even absent from overzealous resec­tion in prior surgeries.'" I" The septum may be congenitally or iatrogenically thickened, de­flected, twisted, or even absent from previous septoplasty procedures or submucous resec­tion. The nasal mucosa in the valve angle may have adhesions or stricture that results in a fixed obstruction with a false-negative Cottle maneuver. Alar collapse with inspiration sec­ondary to weak or absent lateral crural carti­lage can cause nasal obstruction at rest or only during vigorous nasal breathing. Finally, for­eign body is an important differential in young children or adults with mental or psychiatric abnormalities. A thorough history from both the parents and the patient, if possible, helps to confirm the diagnosis. Both organic and in-organic items are possible offenders; especially popular are jelly beans, beads, and seeds. A history of recent onset unilateral purulent rhi­norrhea with intermittent low-grade fever is suspicious for foreign body in the nose. Long-term unilateral rhinorrhea in children is more suggestive of undiagnosed choanal atresia.

Mucosal Pathology
Allergic and nonallergic rhinitis are the most common causes of mucosal nasal obstruction. The mechanism of allergic rhinitis involves an­tigenic stimulation of nasal epithelium with subsequent host response via histamine re-lease. Other symptoms and complaints may include itching of the palate, eyes, or pharynx, as well as sneezing and watering of the eyes.

Nonallergic or vasomotor rhinitis is a multi-factorial response to various nonallergic stim­uli and is a diagnosis of exclusion. Patients with nonallergic or vasomotor rhinitis are dif­ficult to distinguish from their allergic counter-parts because symptoms are frequently the same, including nasal obstruction secondary to congestion, rhinorrhea, and sneezing.

Figure 3. Nasal valve pathology. A, Septal pathology. B, Mucosal pathology. C, Upper lateral cartilage pathology. (By permission of the Mayo Foundation.)

Nonallergic rhinitis with eosinophilia syn­drome (NARES) is an interesting condition that is suggestive of allergic rhinitis, but the serum IgE is normal and allergy skin testing is negative. The cytology of nasal mucosa in these patients demonstrates great numbers of eosinophil, hence the condition is named NARES. There is no seasonal pattern as seen in allergic rhinitis, and symptoms are usually worse when arising in the morning.

Atrophic rhinitis is a less common cause of chronic nasal obstruction. This condition can be idiopathic or occur after turbinectomy. The term empty hose syndrome has been used to describe patients who have undergone nasal surgery with indiscriminate removal of func­tioning nasal tissue (Fig. 4). Symptoms of na­sal obstruction concomitant with nasal crust­ing, foul odor, associated epistaxis, secondary bacterial infections, and even facial pain are typical. Nasal biopsy usually demonstrates squamous metaplasia with atrophy of the submucosa, as well as fibrosis of perivascular space. The loss of nasal resistors typically re­sults in the nasal obstruction symptom.

Rhinitis rnedicamentosa secondary to pro-longed use of topical nasal decongestant sprays may cause development of a rebound phenomenon. The vasoconstriction from the spray is followed by a rebound of vasodilation, which further causes nasal congestion, leading to a cyclic and overuse of the spray.'

Masses
There is a long differential of both benign and malignant nasal masses that cause nasal obstruction. The description of these conditions is beyond the scope of this article, and readers are directed to standard otolaryngol­ogy textbooks for more information. Radio-logic evaluation and biopsy have to be consid­ered on a case-by-case basis. One caveat to remember is that whereas adenoid hypertro­phy is common in young children and even adolescents, adults with nasal obstruction sec­ondary to adenoidal tissue should undergo a biopsy to rule out nasopharyngeal cancer, lymphoma, and other potential malignancies. Angiofibromas are part of the differential in adolescent boys, and again, a biopsy is contra-indicated when clinical suspicion is high. In neonates and children, nasal masses should not undergo a biopsy until a radiologic work-up excludes connection to the central ner­vous system.

Figure 4. Coronal) CT scan of a patient with the empty nose syndrome. Note the complete absence of normal structures, including the inferior turbinates, middle turbi­nates, and medial wall of the maxillary sinuses.

Systemic Illness
Many systemic illnesses have nasal manifes­tations, including obstruction. Granulomatous and infectious diseases are the most common processes that cause nasal obstruction. Wegen­er's granulomatosis (WG) is a systemic vasculitis in which diffuse crusting of the nasal mucosa and nasopharynx may be the first symptom of the illness. Work-up for WG in­cludes testing for antineutrophilic cytoplasmic antibody (c-ANCA) as well as tissue biopsy. ANCA testing is based on indirect immuno­fluorescent findings of granular staining on ethanol-fixed neutrophil cytocentrifuge prepa­rations. c-ANCA is highly specific for WG, in contrast to p-ANCA, which lacks sensitivity and is less useful. Substance abuse, specifically cocaine, frequently results in significant septal perforations over time, which can also cause nasal crusting mimicking a process like WG. In these patients c-ANCA and p-ANCA are usually negative, and biopsy results are incon­clusive. Recently, multiple patients have been evaluated at the Mayo Clinic with several years of rapidly progressive midline destruc­tive process causing significant saddling of the nose as well as complete destruction of the bony and cartilaginous septum, the hard and soft palate, and the maxillary sinus walls. This vasculitic and destructive process is an allergic reaction or sensitization to cocaine. Of note, we have seen palatal fistulas in these patients, but never in a WG patient.

Churg-Strauss syndrome; sarcoidosis; and infectious disease, including rhinoscleroma, tuberculosis, and fungal processes like rhinosporidiosis and histoplasmosis, may all cause nasal obstruction, septal perforation, na­sal discharge, mucosal ulceration, and pain. In many of these diseases biopsy and tissue culture establish the diagnosis.

EVALUATION AND DIAGNOSIS

History
Characterization of nasal obstruction is im­portant in taking a history. The duration of the obstruction is important, because it may help differentiate acute from chronic causes of nasal obstruction. Nocturnal obstruction versus con­stant obstruction, unilateral versus bilateral, and alleviating factors are all informative. As­sociated decrease in smell and taste may be secondary to nasal polyposis if chronic, or due to allergies, rhinitis, or infectious etiology if acute.

The thickness and color of associated rhinor­rhea give clues regarding possible infectious origin. For children who exhibit chronic mouth breathing, nasal obstruction is frequently sec­ondary to adenoid hypertrophy. An otologic history should be sought regarding recurrent otitis media. History of trauma, epistaxis, and recent or past nasal surgery are all informative. Epistaxis may be suggestive of benign or ma­lignant masses. History of allergies, hay fever, and allergy testing are important in differenti­ating the various causes of rhinitis.

Current and recent medications used as well as a thorough medical history are crucial. Mul­tiple medications can contribute to nasal ob­struction as follows:

• Aspirin
• Nonsteroidal anti-inflammatory drugs Enalapril
• Nedicromil
• Tetrahydrozoline
• Lycopodium
• Birth control pills (estrogen and progestin) Iodide
• lohexol Reserpine Epinephrine
• Ephedrine Alcohol Tobacco Cocaine Hashish
• Antithyroid (propyithiouracil)

Sleep disturbance history is an important subject. Patients are asked if they have been told that they snore or have apnea and whether such signs are position related. Patients may report sleeping comfortably on their side only and may prefer only one side. A fixed obstruc­tion remains fixed regardless of patients' sleep­ing position, but a nonobstructed side may become obstructed secondary to mucosal en­gorgement, which occurs with gravity. A pa­tient with an obstructing septal spur on the right may notice that sleeping on the right side is comfortable, because the engorgement is on the same side as the fixed obstruction. If he or she sleeps on the left side, then the mucosa may be engorged secondary to gravity.

Examination
The external nose should be evaluated for deformity. Rarely, a very narrow nose without other structural pathology may cause nasal ob­struction secondary to narrowed pyriform ap­erture, or valve. External nasal deformity sec­ondary to trauma usually indicates septal deformity internally. The bony and cartilagi­nous external nose is examined for anomaly, and an assessment of tip support and skin­soft-tissue envelope thickness is made by pal­pation. The caudal end must be evaluated, be-cause this area is considered a downstream resistor, and a severely deviated caudal end. may distort the columella, the shape of the nares, and the nasal valve angle. Anterior rhi­noscopy and fiberoptic endoscopy should be performed. Anterior rhinoscopy should be done prior to nasal decongestion. If examina­tions are performed only after applying decon­gestants, one may not appreciate the degree of turbinate hypertrophy. Patients should be asked if the decongestants temporarily re­lieved their nasal obstruction, because this may help to direct attention to mucosal pathol­ogy. Pale or boggy mucosa are often seen with allergic and nonallergic rhinitis.

Nasal masses in children should be exam­ined for enlargement while crying or during Valsalva's maneuvers, which is indicative of connection to the central nervous system. En­largement with compression of the internal jugular vein, or a positive Furstenberg sign, is indicative of the same. Positive findings indi­cate the diagnosis of encephalocele, menin­goencephalocele, or meningocele. In contrast to both gliomas and dermoids, the formerly mentioned masses are soft, pedunculated, compressible, and pulsatile.

If a septal deviation contacts the turbinates or lateral nasal wall, it is considered an impac­tion. Impactions near the ostiomeatal complex may contribute to sinus disease due to interfer­ence with normal mucociliary clearance and have been reported to cause facial pain. Nasal polyposis or other masses may be readily visible anteriorly, and if not flexible endoscopy usually allows a complete examination in­cluding the posteior portion of the nasal cav­ity. The adenoid region can also be visualized fully with the flexible endoscope. If a patient has had prior sinus surgery, an attempt should be made to visualize directly the sinus mu­cosa using the endoscope. Nasal smears for eosinophil counts are also informative for distinguishing allergic etiologies of nasal ob­struction.

Figure 5. The Cottle maneuver. The cheek is pulled away from the midline with the physician's index finger to increase the nasal valve angle. A positive Cottle sign is present when this maneuver im­proves nasal breathing. (By permission of the Mayo Foundation.)

Heinberg and Kern" discussed the useful­ness of the Cottle sign as a method of detecting abnormalities of the nasal valve as well as dis­turbance in nasal airflow (Fig. 5). The examiner simply draws the patient's cheek out laterally away from the midline, opening the nasal valve angle as the upper lateral cartilage is pulled laterally away from the septum. If the patient can appreciate an improvement in na­sal airflow or alleviation of nasal obstruction, then valve pathology is implicated. This test may be falsely negative if the patient has sy­nechiae or scarring in the valve angle due to previous surgery or trauma, because despite lateralizing the cheek the valve angle has a fixed obstruction. The nasal valve retractor, designed by Lopez-Infante, is especially useful to examine the nasal valve directly (Fig. 6).

Any nasal masses should be evaluated care-fully for firmness, color, location, and appear­ance. Biopsy may be performed in the office with the anticipation that epistaxis may result. For adolescent boys, any suspicion for juvenile angiofibroma dictates that a biopsy be performed in the operating room. The variable vascular nature of this tumor may result in significant epistaxis and blood loss after biopsy.

Figure 6. The nasal valve retractor. Note the gentle eleva­tion of the external naris so as not to distort the valve angle.

Rhinomanometry and Acoustic Rhinometry

As the managed care model for provision of medical services continues to expand, the demand for objective testing to confirm diag­nosis and prove need for treatment has become imperative. In the evaluation and treatment of nasal obstruction, both rhinomanometry (RM) and acoustic rhinometry (AR) are useful for diagnosis and help to guide the physician in the decision to pursue surgical treatment.

RM is a dynamic technique that allows calculation of nasal resistance from mea­surements of respiratory airflow and differen­tial pressures between proximal and distal portions of a designated airway segment.

Figure 7. Rhinomanometry being performed.

Nasal resistance measures airway pat­ency and the degree of difficulty for a patient to breathe through the nose. This is a dynamic technique because differential pressure and flow are continually changing during a respi­ratory event. Sigmoid pressure-flow curves are plotted with inspiration and expiration. Resis­tance is the ratio between differential pressure and airflow (AP/V). Accordingly, an increas­ing slope represents decreasing resistance to airflow and hence increasing airway patency. Symptoms of nasal obstruction typically occur when total nasal resistance is greater than 3 cm H2O/L/s or when unilateral nasal resis­tance is greater than 7 cm H2O/ L/ s. Although preoperative correlation between subjective nasal obstruction and anatomic obstruction is high using RM, postoperative resistance has been shown not to correlate well with symptoms. This has been attributed to an alteration of the subjective reference point by the patient after surgery. The literature continues to sup-port documented decrease in nasal resistance by RM after surgery of the septum, valve, or turbinates, however (Figs. 8 and 9)."'' AR is a static technique based on the principle plea of acoustic reflection that measures lumen dimensions and cross-sectional area (CSA) of a designated airway segment independent of airflow (Fig. 10). The most resistive segment to nasal airflow is localized to the anterior third of the nose including the nasal valve and area of the inferior turbinate head (Fig. 11).10 Nasal obstruction most commonly results from mu­cosal or structural abnormalities, or a combina­tion of both, in this region (Fig. 12).

AR has been thoroughly studied in nasal models and in probands. Reliability and re­producibility of AR are dependent on several factors. First, the nose piece must not distort the nasal valve region because this is the region of high nasal resistance and flow-limiting com­ponent. A poorly fitting nose piece also distorts the data because any acoustic leakage results in incorrect measurements. To obtain the highest accuracy, anatomically conformed nasal adapt­ers are recommended, and the use of petrola­tum to couple the adapter and the nose avoids acoustic leaks. Studies show that in patients with inferior turbinate hypertrophy, AR dem­onstrates their minimal CSA to correspond to the region of the head of the inferior turbi­nates." Decongestion increases the CSA significantly at the area of constriction as well as the total volume of the nasal cavity. We do not routinely perform allergy-specific intranasal challenge using the offending antigen in our RM and AR testing. Instead, both tests are per-formed with the patient breathing quietly at rest and again at 15 minutes after applica­tion of phenvlephrine hydrochloride na­sal decongestant spray. The repeat test is considered the postchallenge test (Figs. 8, 9, 11, and 12).

Measurement	Pre	LEFT Post	RIGHT Pre Post		TOTAL Pre Post
Resistance (cm H2O/L/sec)	3.98	4.34	3.42	3.74	1.84	2.01
R Broms (cm H2O/L/sec)	3.94	4.30	3.38	3.69	N/A	N/A
Conductance (cc/s/cm H2O)	251.24	230.52	292.30	267.19	543.54	497.71
Flow (cc/sec)	376.86	345.78	438.45	400.78	815.31	746.56

Figure 8. Rhinomanometry data on patient without subjective or objective nasal obstruction. The patient had unilateral nasal resistance below 7 cm H2O/L/sec and total nasal resistance below 3.0 cm H2O/ L/sec. Note no significant change in pressure flow curves and flow postchallenge.

Measurement	Pre	LEFT Post	RIGHT Pre Post		TOTAL Pre Post
Resistance (cm H2O/L/sec)	4.90	5.00	13.11	5.56	3.57 2.63
R Broms (cm H2O/L/sec)	4.86	4.98	13.10	5.54	N/A N/A
Conductance (cc/s/cm H2O)	204.14	199.84	76.27	179.89	280.41 379.73
Flow (cc/sec)	306.21	299.75	114.41	269.84	420.62 569.60

Figure 9. Rhinomanometry data on patient with left premaxilla-maxillary crest septal dislocation. Note that for the left side pressure and flow curve, no change was observed postchallenge (black arrows). This correlates with the lack of increase in flow measurement on the left, in contrast to the right side which demonstrated significant improvement in flow (open arrows) as well as decrease in resistance postchallenge. This demonstrates a fixed left-sided obstruction and mucosal decongestion on the right side.

Figure 10. Acoustic rhinometry being performed.

Both RM and AR have inherent advantages and disadvantages. The advantages of RM in­clude the ability to assess resistance of both compliant and rigid caval segments as well as the mucovascular component of nasal resis­tance. RM, however, requires patient coopera­tion; may be time consuming (20 to 30 min­utes); and measurements are empirical be-cause airflow is nonlaminar. AR is minimally invasive, allows rapid and reproducible re­sults independent of airflow, and is useful in surgical planning for nasal valve pathology. AR, however, does not convey the patient's subjective sensation of obstruction, and its ac-curacy is inversely proportional to the distance away from the nostril.'

Studies show RM is a valuable objective test to substantiate complaints of nasal obstruction and quantitate nasal resistance, and AR is val­uable for identifying specific sites of airflow constriction and evaluating the increase in CSA after surgery. The two methods of evalua­tion are complimentary and are useful to con-firm actual constriction in the nasal cavity and decreased nasal airflow, which often corre­late with subjective complaints of nasal ob­struction.

Nasal Tissue Stiffness Measurements
Many patients have nasal obstruction sec­ondary to inadequate nasal tip support (alar collapse, ptotic tip, and so forth). There are no reproducible methods available to assess and to document nasal tip support. The authors (WJR, DAS) have designed a device that quan­tifies nasal tissue stiffness. We are currently conducting trials to develop normative data for individuals with no subjective complaints of nasal airway obstruction. We are also study­ing the nasal tissue stiffness in patients with pathologic findings preoperatively and mea­suring the changes in nasal tissue stiffness postoperatively. By correlating data on nasal tissue stiffness with airway resistance (RM) and nasal cavity geometry (AR), it appears possible to determine the minimal tissue stiff­ness necessary for adequate nasal patency. Also, with a simple, reproducible method of measuring nasal tissue stiffness we are provid­ing a link between accurate diagnosis and ap­propriate treatment for those individuals with inadequate tip support and resultant nasal air-way obstruction. A key application of this de-vice is to provide objective data to third-party payers to support the need for surgical inter­vention in cases of nasal obstruction secondary to inadequate nasal tissue stiffness (i.e., exter­nal valve collapse, senile tip ptosis, and so forth).

	Req(cmH20/1/m)		Volume(cm^3)	Min Area(cm"2) at Length(cm)
1.	Left Before :	1.668	23.49	0.98 1.86
2.	Right Before:	1.555	21.32	1.02 2.10
4.	Right After :	1.192	29.10	1.29 -5.82
3.	Left After	1.237	30.90	1.25 1.62
1.	Left Before /	Nts-c8m	2.	Right Before / Nts-c8m
4.	Right After /	Nts-c8m	3.	Left After / Nts-c8m

Figure 11. Acoustic rhinometry data on same patient from Figure 8. Note slight increase in minimal cross-sectional area (MCA) for both sides.

276	WEI et al
	Req(cmH2O/1/m)		Volume(cm^3) 12.27	Min Area(cm^2) at Length(cm)
1. Left Before :	3.451	0.45	1.86
	2. Right Before:	6.008	9.26	0.38	1.86
	4. Right After :	3.323	12.08	0.54	1.62
	3. Left After	2.903	13.27	0.51	1.62
	1. Left Before /	Ntsa2m2	2.	Right Before /	Ntsa2m2
	4. Right After /	Ntsa2m2	3.	Left After /	Ntsa2m2

Area (cm2) Comments: Used regular tip.

Figure 12. Acoustic rhinometry data on same patient from Figure 9. The first point of MCA is located in the valve region, also called the I-notch (arrowheads). The second point of MCA is located in the area of the head of inferior turbinate or C-notch (open arrow). Note no significant increase in MCA of left side after decongestion. This reflects the fixed obstruction and narrowing of the cross-sectional area of the left side (black arrows).

Imaging
Both CT and MRI are useful as imaging stud­ies for evaluation of nasal obstruction. In gen­eral, CT scan sections have less motion artifact because they are obtained rapidly and have high spatial resolution, which increases with decreasing thickness of the sections. For evalu­ation of nasal masses, the coronal views enable differentiation between thickened inflamma­tory mucosa or masses and fluid accumulation. Coronal CT also demonstrates septal pathol­ogy, such as deviations and impactions and nasal valve collapse, as well as concha bullosa of the middle turbinates. Disadvantages of CT scanning include degradation of images from dental metallic artifacts and patient position­ing problems.

.M RI provides excellent soft tissue contrast. Depending on the method used, masses in the head and neck region, including the nose, can be characterized and well delineated anatomi­cally. Disadvantages include long scanning time (45 to 90 minutes), high propensity for motion artifact unless patients lie still during the entire procedure, and absolute contraindi­cation in patients with pacemakers.

CONCLUSION
Nasal obstruction is a common symptom with a multi factorial etiology. Directed, com­plete work-up results in appropriate diagnosis and formulation of a treatment plan. Most pa­tients require a complete history, rhinologic examination, and endoscopic examination. Ra­diologic work-up, cultures, biopsy, RM, and AR are useful in some cases. Nasal tissue stiff­ness measurements may play a role in the future.

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