SEPTORHINOPLASTY

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RHINOPLASTY AND SEPTOPLASTY, PART I

SEPTORHINOPLASTY Form Versus Function G. Richard Holt, MD, MSE, MPH

It is commonly understood that the procedure of septorhinoplasty is one of the most technically difficult in the field of facial plastic and reconstructive surgery. The reason for this is that each step that is taken in the total procedure has a impact on subsequent steps, with all closely interrelated to culminate in the final result. In this manner it is different from a radical neck dissection or a tympanoplasty in which little of the procedure is specifically tailored to the patient’s unique anatomy but rather to a well-detailed and uniform surgical plan. Because the steps in septorhinoplasty are so inter-related, it is difficult to separate form from function in the outcome. Patients and insurance companies have trouble with the concept of interdependency, believing that it is either a functional procedure or a cosmetic procedure. Considerable effort is expended by the surgeon in an attempt to help them understand that the two are not usually separable. In this article, we explore these relationships in a general fashion, saving the specific details for each subsequent article. It is critical to the learning of septorhinoplasty that the surgeon understand this interdependency and view the components of the procedure in such a way that changing form does not adversely affect function and vice versa.

From the Division of Facial Plastic and Reconstructive Surgery, Johns Hopkins Medical Institutions, Baltimore, Maryland

OTOLARYNGOLOGIC CLINICS OF NORTH AMERICA VOLUME 32 * NUMBER 1 FEBRUARY 1999

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NASAL FUNCTION AND PHYSIOLOGY

Lest we forget, it is important to emphasize that the primary reason for having a nose is to provide support for the respiratory function. Mainly through the mucosa of the septum and turbinates, humidification and warming of the inspired air is performed (and to a lesser degree on expiration), particles are filtrated, and airway resistance is provided. Indeed, the primary source of respiratory resistance is caused by that of the nasal airway, especially during quiet re~piration.~ The working end of the nose with respect to nasal airway resistance is anteriorly, at the region of the nostrils and nasal valve. Normally the nasal valve (bounded by the caudal end of the upper lateral cartilage and the anterior portion of the inferior turbinate) is the narrowest portion of the nasal airway. In some patients, however, small nostril openings have that role. At any rate, these areas collectively represent the most functionally important segment providing resistance to airflow. The average crosssectional area is less than one square centimeter, and airflow is related proportionately to the fourth power of the radius. Thus, it only takes a small change in the size of the anterior valve/nostril region to significantly increase or decrease airflow into the nasal passages. During quiet nasal respirations in a nasal cavity without anatomic abnormalities, mucosal swelling, or airway collapse, airflow is laminar and linearly related to pressure. If any of these three conditions exist, the airflow becomes nonlaminar and the resultant turbulence changes the relationship between airflow and resistance, and pressure becomes much more complex and less easily modeled. Common conditions that can cause such airflow disturbance include persistent septa1 spurs and deviations, turbinate hypertrophy, nasal valve collapse, nostril narrowing, tip ptosis, and loss of support of the upper lateral cartilages. When such postoperative sequelae occur to reduce nasal airflow and increase resistance, intraluminal pressure decreases at the narrowed area (usually nasal ala or valve) owing to Bernoulli's principle, causing collapse of these structures during inspiration. A classic example of this occurs in patients with total facial paralysis, in whom the nasal dilator muscles are no longer working and the side of the nares collapses. It can also occur if these same muscles are separated from their attachments to the alar cartilages during excessive resection of the lateral crura and debulking of the fibroadipose supporting tissue lateral to the crura. Additional information regarding nasal airflow and resistance preand postoperatively might be obtained through the use of acoustic rhinometry. This test delivers sound waves to the nasal cavity and measures deflection as a function of anatomic location. It is not dissimilar to ultrasound studies. It is particularly helpful in determining cross-sectionalarea

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of various portions of the nasal cavities and how nasal resistance is related to these v o l ~ m e sIn . ~the future, more insurance companies may require some form of objective documentation before septorhinoplasty to authorize surgery that may alter form and correct function.

CONSEQUENCESOFSEPTOPLASTY

A fundamental premise of nasal surgery for many years has been to avoid extensive reconstructive surgery in children because of the potential for affecting growth centers in the nasal skeleton. Located in the dorsal septum and junction of the perpendicular plate with the nasal bones, these growth centers could be retarded by either injudicious resection of the dorsal septum or by osteotomies. No one has definitively stated when it is safe to aggressively alter the form of the pediatric nose without causing functional problems, or when can one safely improve functional airway difficulties without changing the nasal growth pattern. A general consensus is that conservative resections can occur at approximately age 6 but that nasal growth may still be affected even then, although most aspects of facial growth are not.2 It seems reasonable that as long as the dorsal septum (cartilaginous and bony) remain connected to the nasal bones and the septum is not disarticulated into several components, the affect on growth will be minimal. It is likely safe to perform small strip resections of the inferior septum and to perform conservative subtraction-addition rhinoplasties in children as it is in adult^.^ So long as one maintains the structural stability of the nose and does not allow functional abnormality corrections to potentially affect future growth and development, it would be prudent to help these children with their problems. What is the risk of negative cosmetic sequelae when performing septoplasty? According to Vuyk and Langenhuijsen, a review of multiple series demonstrated a 5% risk of aesthetic sequelae.*If a full transfixion incision is used for a septoplasty instead of a hemitransfixion one, then loss of support at the mesial crural level can occur, causing tip ptosis and an alteration in the shape of the nostrils. Airflow can also be altered. Scarring of septa1 flaps can lead to redeviation or deviation in the opposite direction, causing a twisted lower nose and airway obstruction. Finally, exaggerated resection of the quadrilateral cartilage of the septum can cause a saddle deformity, columellar retraction, or nasal valve collapse due to altered cross-sectional diameter and possible compensatory turbinate hypertrophy. There is thus a close relationship between septoplasty and cosmetic appearance, and it can work both ways. A twisted nose can be improved by performing a septoplasty and releasing the upper lateral

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cartilages from the septum, whereas an improperly performed septoplasty can lead to a cosmetic deformity. NASAL VALVE

Because airflow is described by Poiseuille’s law, rate of flow through the anterior nares and nasal valve region is directly proportional to the pressure gradient and to the fourth power of the radius of the opening. Thus, a small change in the radius of the nostril or nasal valve region can have a large effect on rate of flow of inspired air. It is not as critical in the expiratory phase, because this increased resistance serves as a form of positive end-expiratory pressure for the pulmonary alveoli and can be helpful. The superior or dorsal angle of the nasal valve region, between the septum and the upper lateral cartilage, makes an angle of 10 to 15 degrees in whites.’ There is, of course, a wide variation in “normal” anatomy of this angle, with nonsymptomatic individuals having small angles and symptomatic patients with wide angles. As a rule, however, the more narrow the angle, the more likely the rate of inspired air will be accelerated. As is known by rhinoplastic surgeons, compromising the nasal valve, be it at the dorsal angle or through failure to adequately reduce a septa1 deflection, can lead to turbulent airflow and the Venturi effect. Alar collapse or anterior valvular dysfunction following septorhinoplasty can be as troublesome to the patient as a cosmetic deformity. Therefore, it is imperative that proper preoperative planning for nasal surgery always take into consideration what effect that surgery might have on the nostril size and nasal valve integrity. A pinched nasal tip may not directly affect the nasal valve region, but does decrease the cross-sectional diameter of the nostril (intake valve) and can create turbulent airflow from the start. Loss of tip support through the use of a full transfixion incision without placing a columellar support or resuturing the mesial crural feet may give rise to an exaggerated angle of airflow from the nostril to the nasal valve, causing turbulence. The choice of using an intracartilaginous versus an intercartilaginous incision might well mean the difference between loss of cartilage support at the superior-lateral portion of the nasal valve. Understanding the dynamics of each approach and their risk of causing weakness of this portion of the valve must be taken into a c c o ~ n t . ~ Although it is much wiser to prevent nasal valve collapse than to repair it, many possible remedies are available to the rhinoplastic surgeon. Maintaining proper caudal and dorsal quadrilateral cartilage support for the septum will prevent a collapse of the dorsal angle of the valve. Should the procedure require separating the upper lateral cartilages from the septum, such as with a twisted nose in which it cannot be straightened with-

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out doing so, consideration should be given to using cartilage spreader grafts placed between the dorsal septum and the upper lateral cartilages before reapproximating these two elements. Dividing the lateral crus of the lower lateral cartilage at the dome level may improve a boxy nasal tip, but it also may redispose the lateral transected segment to prolapse into the nasal valve region, with further collapse with inspiration. Strictly from a functional standpoint, the separation of the lateral crus is not recommended. Excessive resection of the lateral crus with transection of the attachments of the crus to the fibroadipose support tissue and to the piriform aperture will undoubtedly give rise to collapse of the lateral segment of the valve. If this separation is recognized during the procedure or if identified during a revision rhinoplasty, then suture reattachment may be performed and only support grafts may be inserted to bridge the lateral crus again to the piriform aperature. Additionally, a ”flaring” suture may be applied to augment spreader grafts for lateral crural collapse and narrowing of the dorsal valvular angle according to the technique of Park.6Although septal cartilage grafts work well for this task, the more convex auricular concha1 grafts provide more elevation of the lateral wall of the valve when sutured to the underlying vestibular skin and overlying alar skin. Again, acoustic rhinometry may be helpful in identifying the actual site of the collapse if not clinically evident.

NASAL DORSUM Nasal framework surgery may adversely affect airflow dynamics through altering the size and configuration of the nasal chamber posterior to the nasal valve region. There is a “dynamic interplay” between all of the parts of a septorhinoplasty procedure that affects form and function, making this procedure one of the most difficult in the head and neck region to gain consistently good r e s ~ l t sFor . ~ instance, if the upper lateral cartilages are inadvertently separated from the caudal ends of the nasal bones during hump removal or medial osteotomies, the resultant loss of suspension of the upper lateral cartilages will affect the nasal valve region some distance away. Inappropriate narrowing of the bony nasal vault can impinge on the region of the anterior inferior turbinate, causing indirect airflow turbulence at the nasal valve. Failure to adequately recognize and correct high dorsal deflections of the cartilaginous and bony septum can lead to decreased height of the nasal cavity just behind the nasal valve and add a complexity to the turbulence of the airflow, which can involve the air inspired anterior to the narrowing. Inappropriate removal of dorsal septal and bony skeletal support of the nose will cause a saddle deformity, with significant alterations in the

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shape of the nasal valve and loss of peak efficiency from ideal configuration. The development of a septal perforation following septorhinoplasty is feared by all, mainly because of its affect on the function of the nose and the drying effect of the cross-over turbulence of airflow, as well as the risk of saddle deformity if severe. If mucoperichondrial perforations occur during the surgery directly opposite each other, it is possible to reinsert previously removed cartilage to serve as a blocking material, or more recently, the use of human acellular dermis, which is readily vascularized and epithelialized in the nose. CONCLUSION

Form and function are virtually inseparable in septorhinoplasty. The nose is primarily an organ of function, but our culture has deigned to bestow on its external features great importance in its role as a determinant of our personalities. The rhinoplastic surgeon must appreciate these inter-relationships between structure and function, understand the ease with which problems can occur through failure to understand the interactions, and know how to prevent and reconstruct abnormalities should they occur.

References 1. Broker BJ, Berman WE: Nasal valve obstruction complicating rhinoplasty: Prevention and treatment-Part I. Ear Nose Throat J 7677-78,1997 2. Crysdale WS: How I do it: External septoplasty in children. J Otolaryngol 25:257-260, 1996 3. Guyuron 8: Dynamic interplay during rhinoplasty. Clin Plast Surg 23:223-231, 1996 4. McCaffrey TV, Remington WJ: Nasal function and evaluation. In Bailey BJ (ed): Head and Neck Surgery-Otolaryngology. Philadelphia, Lippincott-Raven, 1998, pp 333-348 5. Meyer R, Jovanovic B, Derder S All about nasal valve collapse. Aesthetic Plast Surg 20141-151, 1996 6. Park SS: The flaring suture to augment the repair of the dysfunctional nasal valve. Plast Reconstr Surg 101:1120-1122,1998 7. Shemen L, Hamburg R: Preoperative and postoperative nasal septal surgery assessment with acoustic rhinometry. Otolaryngol Head Neck Surg 117338-342,1997 8. Vuyk HD, Langenhuijsen KJ: Aesthetic sequelae of septoplasty. Clin Otolaryngol22226232, 1997 9. Younger RAL: Conservative subtraction-addition rhinoplasty. Otolaryngol Head Neck Surg 117330-337,1997

Address reprint requests to G. Richard Holt, MD, MSE, MPH Department of Otolaryngology-Head and Neck Surgery Johns Hopkins Medicine Room 6242 601 N. Carolina Street, 6th Floor Baltimore, MD 21287-0910