ORIGINAL ARTICLE. Quantitative Study of Nasal Tip Support and the Effect of Reconstructive Rhinoplasty. accomplish both an excellent

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1 ORIGINAL ARTICLE Quantitative Study of and the Effect of Reconstructive Rhinoplasty Holger G. Gassner, MD; William J. Remington, MD; David A. Sherris, MD Objectives: To develop a method to quantify nasal tissue resilience, to establish the normal range for persons without nasal obstruction, and to measure the changes in tissue resilience resulting from standard open rhinoplastic techniques. Methods: A new device is described that determines nasal tissue resilience. Measurements on the nasal tip were obtained in triplicate at 5 distinct anatomical sites. Normal values (N=60) were stratified for both sexes into 3 different age groups. Preoperative and postoperative measurements were also obtained in 6 patients who underwent open rhinoplasty for airway obstruction. One patient who underwent intranasal valve repair was included for comparison. All operative patients underwent preoperative and postoperative rhinomanometric measurements. Results: Across all age and sex groups the anterior septal angle is the firmest area of the nasal tip. The mean tissue resilience over the interdomal area and the midcolumella is significantly greater in men than in women. The resilience of the interdomal area exhibits an age effect, with decreasing stiffness over time. The postoperative changes seen correlate well with the placement of structural grafts during rhinoplasty. Conclusions: Nasal tip support can be quantified. Normative values have been established, which allow one to identify areas of inadequate tip support in persons with nasal obstruction. Alterations in tip support resulting from surgical intervention can be quantified. Open rhinoplasty techniques are an excellent tool to restore deficiencies in nasal tip support. Arch Facial Plast Surg. 2001;3: From the Division of Facial Plastic Surgery, Department of Otorhinolaryngology, Mayo Clinic, Rochester, Minn (Drs Gassner and Sherris). Dr Remington is in private practice in Minneapolis, Minn. The authors have no commercial, proprietary, or financial interest in the products or companies described in this article. THE GOAL of rhinoplasty is to accomplish both an excellent aesthetic and functional result. The better the skeletal structures of the nasal tip are preserved, reshaped, and, when necessary, reconstituted, the better functional and cosmetic outcome that can be achieved. It is crucial to understand the various nasal tip support structures and how surgical maneuvers will alter these structures. Didactic approaches to the understanding of nasal tip support include Anderson s tripod concept and the description of the tip support mechanisms. 1,2 Both concepts stress the importance of the strength and shape of the upper and lower lateral cartilages, the integrity of the interdigitation of the upper and lower lateral cartilage, the caudal end of the septum, the membranous septum, the anterior nasal spine, and the skin and soft tissue attachment. Structural deficiencies of the nasal tip can result in an impairment of the delicate architecture of the nasal valve. 3 Being the narrowest portion of the entire airway, the nasal valve regulates nasal airflow and resistance in response to varying inspiratory flow rates. 4 During quiet respiration the valve remains entirely open. As airflow increases during negative inspiratory pressures, the valve begins to narrow, thus, reducing the total valve area and increasing airflow resistance. The delicately balanced partial collapsibility of the nasal valve is determined by the structural resilience of the upper and lower cartilages. 5 Even minor deficiencies in the structural support of the nasal tip may significantly reduce the crosssectional area of the slitlike nasal valve opening. This can cause intermittent or constant nasal airway obstruction. Consequently, the treatment of nasal airway obstruction frequently necessitates reconstructive surgery of the nasal tip to restore adequate skeletal support. Both the external and the endonasal approach are used to gain access to and to reshape the tip. 6 Irrespective of the technique used, the surgical approach to the nasal tip and sep- 178

2 SUBJECTS AND METHODS A device was developed, which is composed of a linear potentiometer (model T25; Novotechnik US Inc, Southborough, Mass), a force transducer (full-bridge, modified ring type), and a rigid tissue indenter (nylon rod) assembled in series. Data acquisition hardware includes an external, 8-channel, 12-bit device (PPIO-DAS8 computer boards; Dell Computers, Round Rock, Tex), which communicates with a personal computer via a standard parallel port. Lab- VIEW 4 (National Instruments, Austin, Tex) programming language is used to acquire, display, and store 2 channels (distance in millimeters, force in grams) of analogue data at a sample rate of 10 Hz. Analogue data are stored as ASCII, tab-delimited characters. Data acquisition occurs with the subject lying in the supine position. The instrument is accurately fixed into position over the subject s nose (Figure 1). Force is applied perpendicular to the skin surface to measure the distance of deformation at the following 5 anatomical locations: the midcolumella, both alae (midway between the dome and the nasofacial groove), the anterior septal angle (cephalad to the dome region in the midline), and the interdomal region (midline between the lower lateral cartilage domes) (Figure 2). The tissue resilience values are derived from the slope of the resulting force-deformation curve. The amount of this displacement is not linear. Such a nonlinear response is referred to as a hysteresis. The profiles typically exhibit a marked increase in the force after displaying an initial linear relationship. To obtain the value of the initial slope, a computerized process was used to fit 2 crossing lines iteratively to the data. One line contained successively more of the initial data points; the other line contained successively fewer of the points in the upward trajectory. Of the resulting series of slope values for the lower portion of the curve, the slope value corresponding to the best-fitting version of the piecewise 2-line model was used as the value of tissue resilience in force (grams) over distance (millimeters). For acquisition of the normative data, male and female subjects were evaluated in 3 different age groups (10 males and 10 females in each age group: group 1, years; group 2, years; and group 3, 45 years). All data were obtained in triplicate. Anterior rhinoscopy and rhinomanometry were performed in all subjects to verify the absence of nasal pathologic conditions. Rhinomanometry was obtained 15 minutes after topical decongestion (1% phenylephrine hydrochloride [Neo-Synephrine] spray; Bayer Corp, Shawnee Mission, Kan) and is reported as total bilateral conductance (expressed in cubic centimeters per second) at 75-Pa nasopharyngeal pressure. Surgical candidates for rhinoplasty were included in the study with nasal obstruction, confirmed by rhinomanometry, caused primarily by nasal valve pathologic abnormality. None of the patients had mucosal or turbinate abnormalities. Six patients, 5 females and 1 male, met these inclusion criteria and were evaluated before and 12 months after surgery. Subjective assessment of nasal airway patency was evaluated on a 10-cm visual analogue scale (0, no airway; 10, ideal airway). Subjective assessment and rhinomanometry were obtained preoperatively and postoperatively. One patient (case 7) underwent only intranasal valve surgery without structural grafting. He is included in the study for comparison. tum inherently weakens the tip further. Thus, techniques like the placement of a suture-fixated columellar strut and tip graft are routinely used during open structure rhinoplasty to restore the structural integrity of the cartilaginous skeleton and, thus, secure airway patency. These grafts are theorized to strengthen the nasal tip and thereby help ensure improvement in the nasal obstruction. Yet, to our knowledge, no data exist to quantify the tissue resilience values of the normal nasal tip. Such data could assist the surgeon in better planning the approach and better evaluating the surgical result. This study presents an effort to establish such normative values and to quantify the alterations of nasal tip support resulting from selected rhinoplastic maneuvers. REPORT OF CASES CASE 1 A 69-year-old woman had undergone 4 previous rhinoplastic procedures. Eight years after the most recent surgery she was seen with near-complete nasal obstruction. On physical examination, no septal abnormalities were present. Owing to scar contracture of the overlying skin soft tissue envelope, her external nose appeared skeletonized and both alae were significantly retracted and collapsed. This resulted in a predominantly fixated nasal valve obstruction, which could be relieved through a Cottle maneuver bilaterally. An external approach to the nasal tip revealed that the domes had previously been divided and the lateral crura were scarred, collapsed, and extremely weak. Resection and replacement of the lateral crura remnants with ear cartilage grafts were performed. These grafts were suture-fixated to the medial crura stumps and the nasal mucosa. A columellar strut and a shield-shaped tip graft were also fashioned from conchal cartilage and sutured in place. CASE 2 A 50-year-old woman had a deviated septum and senile external nasal valve collapse. She had a positive Cottle sign and used a dynamic external valve device (Breathe Right Strip; CNS Inc, Minneapolis, Minn ) before seeking definite surgical treatment to alleviate her nasal airway obstruction. The septum was repaired via a hemitransfixion incision. The nasal tip was exposed through the external approach and on inspection her lower lateral cartilages were found to be flimsy and collapsed. The returning portion of the upper lateral cartilage was noted to be overly developed and a small section was trimmed on either side. The structurally deficient alar cartilages were resected and replaced by conchal cartilage grafts. 179

3 Figure 1. Data acquisition occurs with the subject lying in the supine position. The instrument is accurately placed and fixed into position over the subject s nose. Figure 2. Measurements of nasal tip support are performed over the following 4 distinct anatomical locations: 1, the interdomal region; 2, the anterior septal angle; 3 and 4, both (here left) alae. A columellar strut and shield-shaped tip graft were fashioned from previously harvested septal cartilage and suture-fixated in place. CASE 3 A 36-year-old woman had a severe traumatic saddle nose deformity. On clinical examination, deficient structural support of the columella and saddling of the cartilaginous dorsum was noted. Owing to the lack of septal support, her nasal valve had partially collapsed and settled posteriorly toward the head of the inferior turbinate, thus significantly decreasing her total nasal valve area. Using the external approach, access to the septum was gained from the dorsum. The caudal end of the septum had been resorbed and replaced by scar tissue, necessitating sharp dissection until approximately 1 cm into the nasal cavity. A caudal septal transplant, columellar strut, and tip graft were carved from autogenous rib cartilage and suturefixated in place. A cantilevered, screw-fixated dorsal graft of rib bone and costal cartilage was placed. 7 Her photographs before and 1 year after septorhinoplasty are shown (Figure 3). CASE 4 A 36-year-old white man had a severe posttraumatic saddle nose deformity. The caudal end of the septum was extremely comminuted, and both alae were collapsed owing to deficient septal support. A caudal septal transplant was fashioned from posterior septal cartilage and suture-fixated in place. To correct the saddle nose deformity, a cantilevered dorsal augmentation graft, carved from rib bone and costal cartilage, was inserted and screwfixated. A columellar strut was also placed and both lower lateral cartilages were suture-fixated over the dorsal augmentation graft and to the shield-type tip graft. CASE 5 A 50-year-old white woman had a saddle nose deformity secondary to Wegener granulomatosis. The Wegener granulomatosis was inactive. An external approach revealed that the cartilaginous septum had been completely resorbed and the upper and lower lateral cartilages, although structurally intact, had collapsed because of deficient medial support. A caudal septal transplant and dorsal augmentation graft were fashioned from calvarial bone. Auricular cartilage was used for a suture-fixated shield-type tip graft. CASE 6 A 34-year-old white woman had sustained a traumatic cartilaginous and bony nasal deviation to the right side. Her septum was severely deviated and obstructed the right nasal airway along areas 2 to 4. Resection of this segment was accomplished preserving a 0.5-cm-wide dor- 180

4 A B C D E F G H Figure 3. Case 3. Frontal (A and B), right lateral (C and D), left lateral (E and F), and base (G and H) views before and 1 year after rhinoplasty. sal strut. The resected cartilage was replaced with a posterior septal cartilage and bone graft. Both the left upper and lower lateral cartilages had been significantly traumatized and had collapsed, thus obstructing the left nasal passage. This was corrected by inserting a columellar strut, suture-fixated shield-type tip graft, and leftsided ethmoid bone-stenting spreader graft. Tip symmetry, projection, and opening of the nasal valve area was achieved by dome division and suture-fixation of the domes to the tip graft. 181

5 BTissue Resilience, g/mm ATissue Resilience, g/mm Normative Data: Men Group 1: y Group 2: y Group 3: >45 y Table 1. P Values for a Global Test to Compare Tissue Stiffness Anterior Septal Angle Left Mid Ala Right Mid Ala Columella Interdomal area Anterior septal angle Left mid ala Right mid ala Normative Data: Women statistically significantly greater mean than age groups 2 and 3 (aged, years and 45 years, respectively). As given in Table 1, the mean tissue stiffness across all age and sex groups was significantly different among the 5 anatomical sites, with the exception of the left and the right mid ala. PREOPERATIVE AND POSTOPERATIVE DATA Interdomal Anterior Septal Angle Left Ala Right Ala Columella Nasal Tip Location Figure 4. A and B, Normative soft tissue resilience values for the respective age and sex groups over the 5 distinct anatomical locations of the nasal tip. Error bars indicate 95% confidence interval (±2 SEs). CASE 7 A 60-year-old man reported continued left nasal airway obstruction after undergoing septoplasty 3 times in the past. On physical examination no structural deficiency of the nasal tip was present. However, he had a positive Cottle sign on the left side and was found to have excessive upper lateral cartilage protrusion into the nasal valve angle area on the left side. The returning portion of the left upper lateral cartilage was trimmed to allow the nasal valve to open. A mucoperichondrial flap was elevated and an M-plasty performed at this site. 4 A thin strip of redundant mucosa was trimmed and the mucoperichondrial flap was closed with chromic sutures. No structural grafting materials were placed in this patient. RESULTS NORMATIVE DATA The normative resilience values for the respective age and sex group are shown in Figure 4. The highest resilience across all age and sex groups was identified over the anterior septal angle (mean, 41.0 g/mm). Also across all age groups, the mean resilience of the interdomal region (P<.001, repeated measures of variance) and of the columella (P=.13, repeated measures of variance) was statistically significantly greater in men than in women. The interdomal region exhibited an age effect, with decreasing tissue resilience over time (P=.02, repeated measures of variance). Pairwise comparisons of the resilience values of all 5 anatomical locations revealed that age group 1 (aged, years) had a As summarized in Table 2, 30 resilience values were obtained in 5 anatomical locations preoperatively and postoperatively. Twenty-seven of these 30 values increased as a result of the surgical procedure (P.001). Figure 5 shows the average ratio of the preoperative and postoperative values to normative values across the 6 patients who underwent rhinoplasty, and shows that the anterior septal angle and the midcolumella had the greatest deficiencies in structural support preoperatively. These 2 areas also exhibited the greatest relative increase in tissue resilience after surgical intervention (tissue resilience, from 38.1% to 71.6%; anterior septal angle, from 65.0% to 179.2%; and midcolumella, statistically significant for both areas; P=.03, Wilcoxon signed rank test). The average tissue resilience across these 6 patients over the mid ala exceeded normative values preoperatively. Surgical intervention resulted in a mean increase of alar resilience from 122.8% to 162.2% for the left ala (P=.69, Wilcoxon signed rank test) and from 102.3% to 151.4% for the right ala (P=.03, Wilcoxon signed rank test). Both patients (cases 1 and 2) who received alar replacement grafts exhibited an increase in mid alar resistance over both mid alae (means, 6.3 g/mm preoperatively; 8.2 g/mm postoperatively). The 4 patients (cases 3-6) who underwent rhinoplasty did not undergo any specific surgical maneuver to reinforce alar resilience, such as alar batten or replacement grafts. Interestingly, 6 of the 8 measurements over these patients mid alae increased as a result of the surgical intervention (means, 5.6 g/mm preoperatively; 7.7 g/mm postoperatively), and the mean increase in resilience was similar to that of the 2 patients with alar replacement grafts. No statistically significantly different increase in alar tissue resilience was noted between the group of patients who received alar replacement grafts and the group that did not. Subjective assessment of nasal airway patency improved in all 6 patients who underwent rhinoplasty (mean ratios, 3.2:10 preoperatively; mean ratios, 8.0:10 postoperatively; P=.03, Wilcoxon signed rank test). Total airflow increased in all patients who underwent rhinoplasty who had complete preoperative and postoperative rhinomanometric evaluation (mean total bilateral air- 182

6 Table 2. Preoperative and Postoperative Tissue Resilience Values in 6 Patients With Nasal Airway Obstruction and Ratio to Normative Values* Anatomical Location Absolute Resilience Values, g/cm flows, 228 cm 3 /s preoperatively; 563 cm 3 /s postoperatively; P=.03, Wilcoxon signed rank test) (Table 3). In patient 7, where no structural grafting was done, tip resilience measurements remained unchanged (Figure 6). His airway patency improved by subjective and objective measures. COMMENT Ratio of Preoperative to Postoperative Values to Normative Data, % Patient 1 Interdomal area 28.4/ /323.7 Anterior septal angle 11.3/ /86.0 Left ala 5.2/ /281.0 Right ala 6.4/ /220.0 Midcolumella 19.9/ /288.3 Patient 2 Interdomal area 15.6/ /116.0 Anterior septal angle 12.6/ /39.8 Left ala 5.0/ /131.0 Right ala 3.9/ /81.8 Midcolumella 11.1/ /90.5 Patient 3 Interdomal area 16.6/ /347.2 Anterior septal angle 13.1/ /58.3 Left ala 9.9/ /138.2 Right ala 6.2/ /171.7 Midcolumella 12.7/ /252.5 Patient 4 Interdomal area 14.4/ /309.2 Anterior septal angle 12.9/ /62.0 Left ala 4.9/ /103.0 Right ala 4.1/ /96.4 Midcolumella 12.9/ /121.9 Patient 5 Interdomal area 11.2/ /359.5 Anterior septal angle 7.3/ /119.1 Left ala 3.2/ /200.0 Right ala 2.8/ /187.3 Midcolumella 7.3/ /379.9 Patient 6 Interdomal area 9.0/ /120.5 Anterior septal angle 17.0/ /77.2 Left ala 5.6/ /98.2 Right ala 8.2/ /162.3 Midcolumella 10.1/ /54.0 Average of Patients 1-6 Interdomal area 16.7/ /241.8 Anterior septal angle 14.0/ /71.6 Left ala 6.2/ /162.2 Right ala 5.6/ /151.4 Midcolumella 13.2/ /179.2 *Numerators indicate preoperative values; denominators, postoperative values. The new methods presented allow one to reliably quantitate the nasal tip. 8,9 To our knowledge, reference data Percent of Normative Value Interdomal Anterior Septal Angle Preoperative Postoperative on normative nasal tip resilience values for various age and sex groups are presented for the first time and allow for quantitative assessment of patients with pathologic abnormalities of nasal tip support. The normative data make teleological sense and confirm what the experienced clinician would expect when examining a healthy 65.0 Left Ala Right Ala Columella Nasal Tip Location Figure 5. Average of preoperative and postoperative tip support measurements across 6 patients who underwent open septorhinoplasty. Value given in percent of normal for the respective age and sex group. Table 3. Preoperative and Postoperative Rhinomanometric Evaluation and Subjective Assessment of Nasal Airway Patency Patient No. Rhinomanometry* 10-cm Visual Analogue Scale Result 1 240/756 1/ /448 4/7 3 88/372 2/8 4 /608 4/ /724 4/ /514 4/ /396 2/5 *Numerator indicates preoperative airflow; denominator, postoperative total airflow. Numerator indicates preoperative assessment; denominator, postoperative assessment. Value obtained before topical decongestion (1% phenylephrine hydrochloride spray [1% Neo-Synephrine spray; Bayer Corp, Shawnee Mission, Kan]) was administered. This patient had severe obstruction; 75-Pa pressure was not obtained bilaterally. Tissue Resilience, g/mm Interdomal Anterior Septal Angle Preoperative Postoperative Left Ala Right Ala Columella Nasal Tip Location Figure 6. Preoperative and postoperative tissue resilience by the 5 distinct anatomical locations for patient 7 who underwent nonstructural valve repair. 183

7 nose, namely, nasal tip support decreases with age. The anterior septal angle is the firmest among the locations measured in this study. The interdomal area and the midcolumella are firmer in men than in women. The alae represent the softest locations and there are no statistically significant differences between the 2 sides, and the interdomal and columella stations are softer than the anterior septal angle, but firmer than the alae. In our surgical patients the greatest structural deficits were present over the anterior septal angle and the columella. These areas also exhibited the greatest increase in resilience as a result of the surgical intervention. The causes of nasal airway obstruction are multiple and it is challenging to determine the presence, location, and functional importance of an anatomical abnormality. 10 In many cases, the key to pathologic abnormalities of nasal airway resistance lies in the morphology of the nasal valve area. The 6 cases reported herein cover just a limited example of structural pathologic conditions of the nasal tip that can lead to obstruction of the nasal valve area. An external rhinoplasty was performed in these 6 patients and a columellar strut and/or a tip graft were invariably inserted and suture fixated to reinforce nasal tip support. In 4 of these patients the surgical intervention leads to an increase in tissue resilience over the mid ala without direct reconstruction of the alar structures, such as the lateral crus. As Anderson s model teaches so well, loss of support of 1 of the 3 legs of the nasal tripod causes it to collapse. In these 4 patients the caudal end of the septum no longer provided this support, and collapse of the nasal tip and the valve ensued. We think it is reasonable to conclude that the lateral legs of the tripod, the alar cartilages, generally provide insufficient structural stiffness to maintain a patent nasal valve area. Yet, reconstruction of the medial, collapsed foot of the tripod can result in an improved nasal airway. In addition, as Constantian and Clardy 11 have previously noted, dorsal grafts like those used in 2 of these patients can also contribute to improved airflow. Interestingly, the preoperative mean alar tissue resilience in these patients was higher than the respective normative values. Fibrosis and scarring of the underlying soft tissue may explain this finding in the patient previously operated on. Alar replacement grafts are a last resort in the management of valve obstruction. The ideal replacement graft provides enough support without rendering the nasal tip unduly rigid. The measurements of patients 1 and 2 illustrate that this can be achieved with good functional results through a standard open rhinoplastic technique. Conchal cartilage grafts are both ideally shaped and provide adequate though not excessive rigidity in most cases. The patient who underwent M-plasty reconstruction of a narrow nasal valve angle demonstrates that structural grafts are not necessary in all cases to improve nasal airway obstruction. This case represents one in which there was internal nasal valve obstruction from an excessive returning portion of the upper lateral cartilage. There was no evidence of external nasal valve collapse, or another cause of nasal airway obstruction that one would associate with weak tip support. The results demonstrated that tip resilience did not statistically significantly increase or decrease, but the airway objectively and subjectively improved. These are the results one would anticipate and further validate the methods presented. CONCLUSIONS Nasal tip support can be quantified and normative values now exist. Nasal tip support generally decreases with age. Standard surgical interventions to augment nasal tip support are proven effective. The tripod concept of nasal tip support provides a logical, effective model for conceptualizing nasal tip resilience. The external rhinoplastic approach with structural grafting for nasal tip support deficiencies is an excellent tool to reconstitute the nasal airway. Accepted for publication February 20, Dr Gassner is a research fellow in the Division of Facial Plastic Surgery, Department of Otorhinolaryngology, Mayo Clinic, Rochester, Minn. Corresponding author and reprints: David A. Sherris, MD, Department of Otorhinolaryngology, Mayo Clinic, 200 First St SW, Rochester, MN REFERENCES 1. Anderson JR. The dynamics of rhinoplasty. In: Proceedings of the Ninth International Congress in Otorhinolaryngology. Amsterdam, the Netherlands: Excerpta Medica; Excerpta Medica, International Congress Series, No Tardy ME. Surgical anatomy of the nose. In: Bailey B, ed. Head & Neck Surgery Otolaryngology. Philadelphia, Pa: JB Lippincott; 1993: Kern EB. Nasal valve surgery. 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Paper presented at: fall meeting of the American Academy of Facial Plastic and Reconstructive Surgery; September 23, 1999; New Orleans, La. 10. Wei JL, Remington WJ, Sherris DA. Work-up and evaluation of patients with nasal obstruction [review]. Facial Plast Surg. 1999;7: Constantian MB, Clardy RB. The relative importance of septal and nasal valvular surgery in correcting airway obstruction in primary and secondary rhinoplasty. Plast Reconstr Surg. 1996;98: