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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4366_Библиотеки_им_академика_М_И_Перельмана
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Chapter Achieving Aesthetic Balance of the Infratip Lobule 375
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Nasofrontal
angle
Supratip
break
Tip-defining
points
Columellar-lobular
angle
Columellar-labial
angle
On the lateral view, the infratip lobular projection is delineated by the tip and the
columellar-lobular angle. e infratip lobule is inuenced by the alar-columellar
relationship.
Anatomy of the Lower Lateral Cartilages at the Infratip Lobule
Columellar-lobular angle
Dome
Lateral crus
e trajectory, length, and strength of the middle crura of the lower lateral cartilages dene the shape, contour, and projection of the infratip lobule. e lower
lateral cartilages are divided into three crura: medial, middle, and lateral. ese
three crura are intimately related and undergo complex interactions when manipulated.
Medial crus
Medial crus
e trajectory, length, and strength of the middle crura of the lower lateral cartilages dene the shape, contour, and projection of the infratip lobule.
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e medial crus becomes the middle crus at the columellar-lobular junction, and
the middle crus becomes the lateral crus at the domal junction. e medial crus
determines tip projection and tip support and serves as the caudal leg of the nasal
tripod.
,
At the junction of the medial and middle crura, the trajectory of the
lower lateral cartilage changes to a more cranial direction, rotating along its long
axis. is change in angulation denes the columellar-lobular angle and marks
the beginning of the infratip lobule. e middle crus diverges from the midline
to form the dome of the lower lateral cartilage. is dome marks the transition
of the middle crus to the lateral crus and corresponds to the tip-dening points,
which delineate the superior aspect of the lobule. e lateral crura determine the
amount of alar support and tip rotation, forming the other two (cranial) legs of
the nasal tripod.
CLINICAL ANALYSIS AND PLANNING
Clinical nasal analysis is performed in a systematic fashion that is well described
in Chapter . Evaluation of the infratip lobule begins with the alar-columellar
relationship and the shape of the lower third of the nose. e alar-columellar
relationship is inuenced by the underlying interactions between the medial,
middle, and lateral crura. e shape and strength of the lower lateral cartilage
can be estimated by examination of the alar-columellar relationship. Establishment of a normal alar-columellar relationship will ensure proper positioning of
the medial, middle, and lateral crura.
Chapter Achieving Aesthetic Balance of the Infratip Lobule 377
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Anatomically the infratip lobule overlies the middle crura of the lower lateral
cartilages. As a result, the shape and projection of the infratip lobule are based
on the middle crura. Specic deformities of the middle crura are oen revealed
intraoperatively. However, evaluation of the basal view can provide an indication of their length. In an ideal nose, the columella/lobule ratio is approximately
:. When the lobular portion is excessive, the middle crura are likely elongated.
Equally important is the angle of departure between the lateral crus and the alar
rim and the rotational orientation of the lateral crus with respect to its cranial
and caudal edges. A lateral crus with a large angle of departure from the alar
rim will have a recessed and weak facet, causing a pinched tip and overprojected
infratip lobule. is is oen superimposed onto an abnormal rotational orientation with the caudal edge of the lateral crus below the cranial edge, which compounds the deformity. Alar support procedures such as a lateral crural strut gra
or alar contour gra can oen compensate for weaknesses in alar support.
,
is conguration is common in patients undergoing primary rhinoplasty who
have very weak lower lateral cartilages. A rotational orientation with the caudal
edge above the cranial edge will produce alar notching and nostril aring, also
leading to excess infratip lobular projection. Deformities including alar retraction or discrepancies in the alar-columellar relationship are seen in secondary
rhinoplasty patients who have a weak or diminutive lower lateral cartilage aer
overzealous excision.
Infratip lobular deformity can be caused by structures other than the lower lateral
cartilage. Prominence of the anterior septal angle and caudal septum, plunging
tips, and tension tips can lead to excess infratip lobular projection. Maneuvers
that correct these problems include caudal septal resection and dorsal reduction,
with appropriate medial crural and columellar support.
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CLASSIFICATION OF INFRATIP LOBULAR DEFORMITIES
Five types of infratip lobular deformities have been described. eir cause is either intrinsic or extrinsic. Intrinsic causes are deformities or abnormalities in the
lower lateral cartilage, whereas extrinsic causes involve structures other than the
lower lateral cartilage. Correct classication is dependent on a thorough preoperative nasal analysis and intraoperative conrmation of the anatomy.
Classication and Causes of Infratip Lobular Deformities
Type
I Intrinsic; middle crus too long
II Intrinsic; middle crus too wide
III Intrinsic; lower lateral cartilage malposition or asymmetry
IV Intrinsic; combination of intrinsic type I, II, and III abnormalities
V Extrinsic; prominent caudal septum or anterior septal angle
Cause
Type I: Intrinsic, Middle Crus Too Long
Lateral crus
Medial crus
Middle crus
In type I deformities, the middle crus is too long. e excess vertical height of
the middle crus is limited by its surroundings, causing it to buckle or bow outward inferiorly. is results in excess infratip lobular projection. Depending on
the relative lengths of the middle crura, this can be symmetrical or asymmetrical between the le and right sides. In addition to an overprojecting lobule, the
deforming forces of a buckled middle crus can cause asymmetries of the lateral
crus or the tip-dening point, leading to associated tip asymmetries.
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In type I infratip lobular deformities, the excess vertical height of the middle crus
is limited by its surroundings, causing it to buckle or bow outward inferiorly. is
results in excess infratip lobular projection.
Type II: Intrinsic, Middle Crus Too Wide
Lateral crus
Medial crus
Middle crus
In type II infratip lobular deformities, the middle crus is too bulky or wide.
is may or may not be associated with discrepancies in vertical height. A wide
middle crus will push on the infratip lobule, causing overprojection. Although
the trajectory of the middle crus is within normal limits, the eect of bulk and
width pressing on the so tissue envelope is prominence of the infratip lobule.
is deformity is oen seen in conjunction with a boxy or bulbous tip.
In type II infratip lobular deformities, a wide middle crus pushes on the infratip
lobule, causing overprojection.
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Type III: Intrinsic, Lower Lateral Cartilage Malposition
or Asymmetry
Lateral crus
Medial crus
Middle crus
Type III infratip lobular deformities have a malpositioned or asymmetrical lower
lateral cartilage. is most oen relates to the angle of departure between the
lateral crus and the alar rim or to the rotational orientation of the lateral crus
with respect to its cranial and caudal edges. In an ideal infratip lobular projection,
the cranial and caudal edge of the lateral crus lie in the same plane. Malposition
of the lower lateral cartilage is oen superimposed on intrinsic asymmetries or
deformities that require suture correction.
Type III infratip lobular deformities most oen relate to the angle of departure
between the lateral crus and the alar rim or to the rotational orientation of the
lateral crus with respect to its cranial and caudal edges.
Middle crus
Middle crus
Chapter Achieving Aesthetic Balance of the Infratip Lobule 381
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Type IV: Intrinsic, Combination of Type I, II, and III Abnormalities
Lateral crus
Medial crus
Type IV infratip lobular deformities involve a combination of types I, II, and III.
Multiple asymmetries and deforming forces are common, and the middle crus
is too long (type I) and too wide (type II). e le and right middle crura may
be similar but are oen asymmetrical. Deformities of the middle crura are oen
superimposed on abnormalities of lower lateral cartilage (type III).
Type V: Extrinsic, Prominent Caudal Septum or Anterior
Septal Angle
Lateral crus
Medial crus
Type V infratip lobular deformities are extrinsic to the lower lateral crura. A
prominent caudal septum or anterior septal angle can displace the infratip lobule, causing prominence. Septal abnormalities can also cause distortions in nasal length (long nose), nasal height (tall nose), the columellar-labial angle, or the
columellar-lobular angle, all of which can lead to a perceived excessive infratip
lobular projection. Furthermore, septal prominence can contribute to a tension
tip or a plunging tip, causing overprojection of the infratip lobule.
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OPERATIVE TECHNIQUE
e operative technique requires analysis and classication of the infratip lobular
abnormalities. e surgical approach to the correction of excess infratip lobular projection treats each type of deformity in a stepwise fashion from medial to
lateral.
e surgical approach to the correction of excess infratip lobular projection treats
each type of deformity in a stepwise fashion from medial to lateral.
If a prominent caudal septum is causing overprojection of the middle crus and
infratip lobule, the caudal septum is trimmed.
e rst maneuver in the correction of intrinsic deformities is to verticalize the
medial crus by placing a medial crural suture. is maneuver will dene the junction of the medial and middle crura. With the incorporation of portions of the
middle crus, a high intercrural suture can shorten the middle crus by absorbing its length and by denition control the projection of the infratip lobule. is
suture also begins to dene the amount of tip projection and provides a stable
middle base for the nasal tripod. In patients with weak tip support, a columellar strut gra is incorporated. is technique is used to treat type I deformities.
Chapter Achieving Aesthetic Balance of the Infratip Lobule 383
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e shape of the middle crus can be changed by cephalic trim, and in some cases
caudal trim is required. is will control its width. Excess width or bulk of the
middle crus can lead to excess infratip lobular projection and paradomal fullness and bulbosity. Cephalic trim is performed to create symmetrical crura and
improve tip denition and lower lateral symmetry. If the lower lateral cartilage
is weak or convoluted, a lateral crural turnover ap can be placed to narrow the
width of the alar rim strip while using the intrinsic forces in the cartilage to improve the shape and strength of the lateral crus. e caudal aspect of the middle
crus can be trimmed if necessary. If tip support is a concern, resection of the an
terocaudal septal angle can achieve the same eect as caudal trim of the middle
crus without weakening the lower lateral cartilage. is technique is used to treat
type II deformities.
-
e junction of the middle and lateral crura is set using an interdomal suture. In
some cases, a shaped columellar strut gra with intercrural sutures is required.
Placement of the initial interdomal suture narrows the angle of divergence and
begins the process of dening the junction of the middle crus with the lateral
crus and the tip-dening points. is technique is used to treat type III and typeI
deformities.
e junction of the middle and lateral crura is set using an interdomal suture.
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At this point, intrinsic asymmetries of the lower lateral cartilages are noted, and
the rotational orientation of the lateral crus is adjusted. Transdomal sutures will
dene the junction of the middle and lateral crura, establish the length and shape
of the middle crus, and determine infratip lobular projection. Transdomal sutures are usually placed toward the leading edge of the lower lateral cartilage. A
slightly more caudal placement derotates the tip and controls the infratip lobular projection. Dierential placement of transdomal sutures in the craniocaudal
dimension allows shaping to improve symmetry of the domes and changes the
rotational orientation of the lateral crus. ese sutures will nalize the shape of
the tip-dening points and the infratip lobule. e endpoint of transdomal suturing is a straight and at lateral crus and proper rotational orientation.
e endpoint of transdomal suturing is a straight and at lateral crus and proper
rotational orientation.
e more convex the lateral crus, the larger the bite and the more lateral the
placement. A lateral crus that is less convex requires a more medial, smaller bite.
e nal result of transdomal suture placement is a symmetrical, aesthetic nasal
tip with well-proportioned crura. e precise placement of the transdomal sutures cannot be overemphasized. e position and orientation of the transdomal
sutures will sculpt the tip and rotate the lateral crus. e rotation of the lateral
crus will determine the rim elevation and the appearance of the infratip lobule. Alar rim position corresponding to a rotational level in which the cephalic
and caudal edges are on the same plane will provide an ideal infratip lobular
projection.
Alar rim position corresponding to a rotational level in which the cephalic
and caudal edges are on the same plane will provide an ideal infratip lobular
projection.
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