Keywords Philtrum - Philtral ridge - Cleft Lip - Scar - Morphology
An understanding of the morphological characteristics of the normal philtral ridges
in our population is essential for the right choice of incision in cleft lip reconstruction.
Introduction
There is a complex and delicate relationship between the shape and proportions of
philtral ridges, base of the columella nasi, and the rest of the lip, which plays
an important role in its normal appearance. It is well-accepted that these structures
exhibit differences among individuals and may also have racial variations.[1 ] Understanding the normal morphology and its variations is essential to achieve symmetry
and a near-normal appearance during cleft lip repair. This is particularly important,
since the surgeon needs to position the incisions to preserve the philtral ridges
or simulate them. In the unilateral cleft, this must correspond to its opposite side,
while in the bilateral, it should form or simulate the structure in accordance with
the shape of the philtral columns and its relationship to the nostril prevailing in
the local population.
The rotation advancement technique or its variants, undoubtedly one of the most popular
operations for cleft lip repair, assumes that the philtral ridges end at the columellar
base. Hence, the incisions are designed to simulate these to achieve a normal looking
lip. However, it was the observation of Jyotsna Murthy that in a significant number
of our patients, this assumption does not hold good and the philtral ridge ended lateral
to the columellar base into the nasal sill. (Personal communication) In these patients,
the rotation incision including the Mohler’s modification cuts across the upper third
of the philtral column, placing the incision across this landmark structure.
Although normative data from anthropological studies of the lip and philtral ridges
have been published from different parts of the world, none was found to emphasize
the variations in its relationship with the columellar bases. Further, there are no
studies regarding these variations in the south Indian population.
Aim and Objectives
To describe the morphology of philtral ridges of the lip and their relationship to
the columellar bases in a sample of the south Indian population. The objective of
this observational study is to achieve this by determining whether the upper end of
the philtral ridge terminates at the columellar base or further laterally in the nasal
sill.
Methods
A total of 115 healthy children with no known congenital anomalies from the southern
Indian states of Tamil Nadu and Karnataka were evaluated. There were 88 boys and 27
girls. The ages ranged between one and twelve years.
Inclusion criteria: Children reporting for routine immunization to the hospital and
school children without any visible congenital or other anomalies were studied. A
printed consent was obtained from one or both parents.
Exclusion criteria: Children with congenital anomalies and those who were crying or
exhibiting behavior where the lips were not in repose and whose parents/parent did
not provide consent for the study.
Following direct observation and recording of findings by the principal investigator,
standard two-dimensional (2D) frontal view photographs of the upper lip were taken
using flash photography for the record and further evaluation.
All children were photographed with the lips in repose. The objective lens was positioned
at a prefixed distance of one meter from the subject for standardization. The images
were then cropped to fill the frame as shown in
[Fig. 1 ]
.
Fig. 1 (A) The Philtral ridge terminates at the medial nasal sill lateral to the columellar
base. (B) The Philtral ridge terminates at the columellar base or fades before reaching
it.
The study subjects were assigned to one of the two groups by the principal investigator
(R1), according to the relationship of the upper pole of the philtral ridges to the
columellar base.
Type A: The upper pole of the philtral ridge terminates at the medial nasal sill just
lateral to the columellar base (
[Fig. 1 A ]
) Type B: The philtral ridge terminates at the columellar base or fades before reaching
the columellar base (
[Fig. 1 B ]
).
All observations were further evaluated again by two independent observers (R2 and
R3), using the standardized 2D photographs, and the results were ratified. In cases
where there was a dispute between the findings of the observers, the type was assigned
according to the majority finding. The whole exercise of evaluating the photographs
by R2 and R3 was repeated after an interval of 48 hours to establish intrarater reliability.
Descriptive statistical analysis using software SPSS 21 was used to assess reliability.
Results
Of the 115 evaluated, 100 children whose images satisfied all the required parameters
were included in the study. Our findings were type A (philtral ridges extend lateral
to the columellar base to end in the medial nasal sill) 74%; type B (The philtral
ridges terminate at the columellar base or fades before reaching the columellar base)
26% ([Table 1 ]). There is a statistical significance difference between type A and type B at 95%
(p < 0.05) ([Table 2 ]). All the observers (R1, R2, and R3) unanimously agreed in their evaluations in
these cases (interrater reliability) and were consistent on intrarater reliability
tests ([Table 3 ])
Table 1
Observer’s evaluation of the philtral ridge to the columellar base
Relationship of philtral ridge to columella base
R1
> 48 hours
R2
> 48 hours
R3
> 48 hours
Type A: philtral ridges extend lateral to the columellar base to end in the medial
nasal sill
74
72
71
75
74
75
Type B: philtral ridges terminate at the columellar base or fades before reaching
the columellar base
26
28
29
25
26
25
Table 2
Group statistics
Groups
n
Mean
SD
Standard error mean
t value
p -value
Abbreviation: SD, standard deviation
R1
Type A
72
1.03
0.165
0.020
– 24.407
0.000
Type B
28
1.96
0.189
0.036
R2
Type A
72
1.04
0.201
0.024
– 20.929
0.000
Type B
28
1.96
0.189
0.036
R3
Type A
72
1.03
0.165
0.020
– 20.535
0.000
Type B
28
1.93
0.262
0.050
R1_after_48_hrs
Type A
72
1.03
0.165
0.020
– 24.407
0.000
Type B
28
1.96
0.189
0.036
R2_after_48_hrs
Type A
72
1.03
0.165
0.020
– 30.990
0.000
Type B
28
2.00
0.000
0.000
R3_after_48_hrs
Type A
72
1.03
0.165
0.020
– 24.407
0.000
Type B
28
1.96
0.189
0.036
Table 3
Inter- and intrarater reliability
R1
> 48 hours
R2
> 48 hours
R3
> 48 hours
Type A
0.481
0.481
0.518
0.481
0.481
0.481
Type B
0.296
0.296
0.552
–
0.386
0.296
Discussion
With its prominent central position on the lip and complex anatomy, it is imperative
that better understanding of the morphology of the philtral ridges will lead to better
aesthetic outcomes in cleft lip repair. The present study concentrates on this complex
relationship between the philtral ridges, the columella and the nasal sill, because
of its significance in the choice of incisions for cleft lip repair, which can place
scars that can potentially distort these structures.
In our study, we found that 74% of the subjects fell under type A, where the philtral
ridges extended lateral to the columellar base to terminate at the medial end of the
nasal sill. (
[Fig. 1 ]
). Surprisingly, the phenotypic variation where the philtral ridges terminated at
the columellar base or faded before reaching it (type B), which coincides with the
conventional descriptions of the philtral column, accounted for only 26% of the subjects
studied.[2 ]This may be presumed to be a racial variation, since the ancestral south Indian population,
although an admixture of several races, is thought to be distinct from the populations
from the other parts of the subcontinent.[3 ]
Several anatomical studies have already described a complex interplay of the muscle
fibers of nasalis, orbicularis oris, levator labii superioris, and their subcutaneous
insertions, forming the philtral ridges.[4 ]
[5 ] Namnoum et al demonstrated in their studies that the philtral ridges are formed
by thickened dermis and dermal appendages.[6 ] They showed that the muscle fibers of the superficial orbicularis oris were especially
rich near the vermilion border and become sparse as they come close to the base of
columella nasi. An understanding of this complex relationship of components of orbicularis
oris muscle and the overlying dermis is useful in planning the incision and the reconstruction
of a consistent philtral column in a cleft lip repair.[7 ]
The landmark study by Mori et al, which classified the variations in the shapes of
the philtral complex in 109 Japanese children, recognized the significance of its
relationship to the columella of the nose when they classified it into four distinct
groups.[8 ]The findings of this study corroborate the prevalence of distinct differences in
facial morphology in individuals as well as varying trends among ethnic groups and
races.[9 ]
[10 ]
[11 ] This emphasizes the need for separate standards of facial morphology for different
ethnic groups.
The ultimate aim of cleft lip repair is to make the child appear normal. Although
complete normalcy is not possible at the present time due to our inability to prevent
scarring, near normal results are only possible when scars from the lip repair do
not cross the natural landmarks such as philtral ridges.
The rotation advancement method originally described by Millard, and its variations,
result in the scar arching from cupid’s peak cranially across the upper one third
of the philtral column.[12 ] Mohler recognized this in his study of the philtral ridges of elementary school
children, which he classified according to their relationship to the columella.[2 ] He found that in most cases, philtral ridges diverged at the columellar base to
reach the lateral border of the columella. This was the basis of his modification
of the rotation advancement method and for using the columellar base as a silent donor
site. Although he also noted that in 7% of children, the philtral ridge faded out
before reaching the columellar base, he did not describe any subject where the philtral
ridge diverges well away from the columellar base to end at the nasal sill lateral
to it, as in the subjects classified as type A (74%) in our study.
Hence, it may be argued that the variants of rotation advancement technique of cleft
lip repair, including the Mohler’s modification, may place incisions that cross its
upper one-third, resulting in an unacceptable scar across the philtral ridge in a
substantial portion of our population (
[Fig. 2 ] A ). The straight-line repair or its variations where the scar extends to the nasal
sill along the line of cleft may be more appropriate in these patients, since the
incision preserves the philtral column, which is essential for a near-normal appearance
of the repaired lip.
Fig. 2 Comparison of scars following lip repair by rotation advancement and straight-line
techniques. (A ) Rotation advancement repair with the scar extending to the columellar base. (B ) Straight-line repair with the scar extending lateral to the columella into the nasal
sill region (please note the overall aesthetics and symmetry).
Although we consider our findings to be significant to initiate a discussion on the
preference of technique for cleft lip repair in this part of the world, a larger study
with a comparison of the populations from various regions of the subcontinent with
larger sample sizes may be needed for conclusive evidence.
Conclusion
The surgeon should take into consideration the racial and ethnic variations in morphology
of the philtral ridges in the local population while choosing an appropriate technique
for cleft lip repair.
