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Quantitative Study of Nasal Tip Support and the Effect of Reconstructive Rhinoplasty
Holger G. Gassner, MD;
William J. Remington, MD;
David A. Sherris, MD
Arch Facial Plast Surg. 2001;3:178-184.
ABSTRACT
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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.
INTRODUCTION
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 cross-sectional 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 septum 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.
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. LabVIEW
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).
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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.
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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.
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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, 18-31 years; group 2, 32-45 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.
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. 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 suture-fixated 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).
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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.
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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 screw-fixated.
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 dorsal 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
left-sided 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.
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, 18-31 years) had a statistically
significantly greater mean than age groups 2 and 3 (aged, 32-45 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.
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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).
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Table 1. P Values for a Global Test to Compare
Tissue Stiffness
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PREOPERATIVE AND POSTOPERATIVE DATA
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).
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Table 2. Preoperative and Postoperative Tissue Resilience Values in
6 Patients With Nasal Airway Obstruction and Ratio to Normative Values*
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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.
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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 airflows, 228 cm3/s preoperatively; 563 cm3/s postoperatively; P = .03, Wilcoxon signed
rank test) (Table 3).
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Table 3. Preoperative and Postoperative Rhinomanometric Evaluation
and Subjective Assessment of Nasal Airway Patency
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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.
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Figure 6. Preoperative and postoperative
tissue resilience by the 5 distinct anatomical locations for patient 7 who
underwent nonstructural valve repair.
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COMMENT
The new methods presented allow one to reliably quantitate the nasal
tip.8-9 To our knowledge, reference
data 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 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 Clardy11 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.
AUTHOR INFORMATION
Accepted for publication February 20, 2001.
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 55905.
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.
REFERENCES
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1. Anderson JR. The dynamics of rhinoplasty. In: Proceedings of the Ninth International Congress
in Otorhinolaryngology. Amsterdam, the Netherlands: Excerpta Medica;
1969. Excerpta Medica, International Congress Series, No. 206.
2. Tardy ME. Surgical anatomy of the nose. In: Bailey B, ed. Head & Neck Surgery–Otolaryngology. Philadelphia, Pa: JB Lippincott; 1993:2109.
3. Kern EB. Nasal valve surgery. In: Krause CJ, Mangat DS, Pastorek N, eds. Aesthetic
Facial Surgery. Philadelphia, Pa: JB Lippincott; 1991.
4. Kern EB. Surgical approaches to abnormalities of the nasal valve. Rhinology. 1978;16:165-189.
PUBMED
5. Goode RL. Surgery of the incompetent nasal valve. Laryngoscope. 1985;95:546-555.
ISI
| PUBMED
6. Kienstra MA, Sherris DA, Kern EB. Osteotomy and pyramid modification in the Joseph and Cottle rhinoplasty
[review]. Facial Plast Surg. 1999;7:279-294.
7. Sherris DA. Caudal and dorsal septal reconstruction: an algorithm for graft choices. Am J Rhinol. 1997;11:457-466.
PUBMED
8. Gassner HG, Remington WJ, Sherris DA. Quantifying nasal tip support. Paper presented at: spring meeting of the American Academy of Facial
Plastic and Reconstructive Surgery; April 28, 1999; Palm Desert, Calif.
9. Beaty MM, Dyer II WK. Structural integrity in rhinoplasty: a quantitative assessment of nasal
framework tensile strength in primary and secondary rhinoplasty. 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;7:263-278.
11. 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;98:38-54.
PUBMED
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