Title: Aging of the Mid-face Bony Elements: A Three Dimensional CT Study
Authors: Robert B. Shaw, Jr. BS, David M. Kahn MD
In order to effectively rejuvenate the aging face, it is necessary to
understand the dynamic aging process. Much is known in regards to how
the face loses volume as the soft-tissue structures age. Epidermal
thinning and the decrease in collagen cause skin to lose its
elasticity. Loss of fat, coupled with gravity and muscle pull, leads
to wrinkling and the formation of dynamic lines. These factors
contribute to the formation of jowls, crow’s feet and the drooping
appearance of aged facial skin. The aging process also affects the
facial bones. There are various studies, from the analysis of male
skulls, suggesting maxillary clockwise rotation and the enlargement of
the bony orbit with changes to its curvilinear form with age.1,2
Changes in face width and mid-face height have also been demonstrated
with increasing age.3 In this multi-part study we will demonstrate how
specific bony aspects of the face change with age in both men and
women and what affects that may have on the application of facial
cosmetic surgery.
Method: Facial bone computed tomography (CT) scans were obtained from
60 Caucasian patients, (30 female, 30 male). There were ten male and
ten female patients in each of three age categories: young (25-44
years), middle (45-64 years), and old (65+ years), (Table 1). Each CT
scan underwent 3D reconstruction with volume rendering and the
following measurements were obtained: glabellar angle (maximal
prominence of glabella to nasofrontal suture), pyriform angle (nasal
bone to lateral inferior pyriform aperture), and the maxillary angle
(superior to inferior maxilla at the articulation of the inferior
maxillary wing and alveolar arch). Each angle was taken in reference
to the sella-nasion line. The area of the nasal aperture was also
measured on each 3D model. Analysis of variance and Student’s t-test
were used to identify any trends between age groups, with results
considered significant at a p-value less than .05.
Results: The glabellar angle in our female population had a
statistically significant decrease from the young to middle age group
(p=.007), while our male population had a significant decrease from
the middle to oldest age group (p=.046).
The maxillary angle in our female population showed a significant
decrease from the young to middle age group (p=.0023), and from the
middle to oldest age group (p=.0475). The maxillary angle in our male
population also had a significant decrease from the young to middle
age group (p=.0171), and from the middle to oldest age group (p=.0092).
For both genders, the maxillary angle was greatest in the young age
group.
The pyriform angle did not show significant change between age groups
for either gender.
There was a significant increase in nasal area from the young to
middle age group for our male population (p=.0346) and female
population (p=.0373). For both genders, the nasal aperture area was
greatest in the oldest age group.
Discussion: The decrease in glabellar angle found in this study
suggests that the supra-orbital bar and nasion recede with age. This
bony change may result in the appearance of brow ptosis and lateral
orbital hooding noticed in the older population. The eyebrows appear
to droop below the receded orbital rim and the upper eyelid skin
appears deflated. The maxillary angle decrease may be responsible for
the malar fat pad sliding down and forward, causing it to push up
against the nasolabial crease and thus making it more prominent. The
increase in the nasal area makes it evident that the bone recedes
around the pyriform aperture, without a change in the pyriform angle.
This may result in the appearance of nose elongation and drooping
noticed with aging. These results suggest that the bony elements of
the mid face change dramatically with age and coupled with soft-tissue
changes lead to the appearance of the aged face. Thus, we feel the
most effective approach towards facial rejuvenation should be two-fold:
restoring volume to compensate for the loss of bony volume, and
lifting and reducing the aged and less elastic soft tissue envelope. A
balanced approach to facial rejuvenation between volume augmentation
and soft tissue envelope repositioning and reduction will hopefully
avoid the distortions of either approach alone.
Table 1.
Average Age by Gender in each Age Category
Mean(Years)
Std. Dev.
Young
Male
Female
33.8
30.4
7.6
5.3
Middle
Male
Female
57.7
54.5
4.8
4.5
Old
Male
Female
75.4
75
6.6
7.6
Table 2.
Mean Angular and Area Measurements by Gender in each Age Category
Age Category
Young
Middle
Old
Measurement (SD)
Glabellar Angle Male
Glabellar Angle Female
73.3(3.6)
77.1(2.9)
71.8(3.7)
73.4(2.6)a
68.6(3.0)b
71.4(5.5)
Maxillary Angle Male
Maxillary Angle Female
62.3(3.3)
64.4(5.0)
58.4(3.3)a
57.7(3.4)a
53.2(4.6)b
53.6(5.0)b
Pyriform Angle Male
Pyriform Angle Female
60.1(3.1)
60.5(4.4)
59.1(3.8)
56.7(4.6)
60.3(3.4)
56.9(4.0)
Nasal Area(mm2) Male
Nasal Area(mm2) Female
610.4(44.4)
497.9(47.7)
664.4(60.1)a
550.1(55.8)a
Legend:
669.8(44.5)
556.3(51.5)
a: statistically significant decrease from young to middle age group
b: statistically significant decrease from middle to old age group
Figure 1.
Example CT scan of a female subject in the young age group compared to a
female subject in the old age group. Mean angular measurements are applied
to each image.
References:
1. Pessa, J.E., and Chen, Y. Curve Analysis of the Aging Orbital
Aperture. Plastic and Reconstructive Surgery 109:751-755, 2002.
2. Pessa, J.E. An Algorithm of Facial Aging: Verification of lambros’s
Theory by Three-Dimensional Stereolithography, with Reference to the
Pathogenesis of Midfacial Aging, Scleral Show, and the Lateral
Suborbital Trough Deformity. Plastic and Reconstructive Surgery
106:479-487, 2000.
3. Bartlett, S.P., Grossman, R., Whitaker, L. Age-Related Changes of
the Craniofacial Skeleton: An Anthropometric and Histologic Analysis.
Plastic and Reconstructive Surgery 90:592-599, 1992.