INTRODUCTION
The gradual loss of skin quality overtime often becomes
a barometer of age, which in turn, fosters the immense
patient demand for skin restoration procedures. In 2012,
facial rejuvenation treatments, including surgical and minimally-
invasive procedures, accounted for an astonishing 74% of all
cosmetic procedures performed.1 Considerations for the cause
of skin aging and loss of quality include, but are not limited
to, loss of subcutaneous fat, prominence of platysmal banding
through muscle laxity, jowling along the mandibular border,
and excess skin laxity resulting from a decline in collagen
and elastin.2 Treatments range from botulinum toxin injections
to more invasive surgical procedures. A widely used non-invasive
skin tightening solution has been transcutaneous radiofrequency,
which exerts a thermomechanical effect to induce
neocollagenesis, denaturation of multi-chain collagen crosslinks,
immunological and wound healing responses, collagen
contraction, and collagen fibril size increase.3-5 Additionally,
shorter, heat-stable intermolecular cross-links are established,
which increase rubber-elasticity of the collagen polymer.3
Transcutaneous radiofrequency, through an external applicator,
permeates the tissue generating an alternating electromagnetic
field that increases the kinetic activity of ions.6,7 Increased
ion kinetics and oscillations, in turn, facilitates resistive tissue
thermogenesis.7 However, resistance-induced thermogenesis
mandates that an appropriate quantity of energy reach the target
tissue without imposing ill-effects on the epidermis.8 Accordingly,
a major disadvantage of transcutaneous radiofrequency is
the poor penetration of radiofrequency energy into deeper dermal
and hypodermal layers, which can result in tissue arcing and
subsequent scar formation.8 Additionally, and of great importance,
the temperature threshold for inducing an epidermal burn
is lower than the therapeutic temperature thresholds required
for collagen remodeling. Accordingly the epidermis and outer
dermal layers must be appropriately monitored and cooled to
prevent untoward effects. Presently, temperature monitoring is
done via a handheld infrared laser thermometer, without proper
subdermal temperature monitoring and control.
Based on limited thermoregulation, broad, or volumetric,
transcutaneous heating is limited in its ability to effectively
treat superficial subdermal layers as well as deep adipose and
subcutaneous tissue, without affecting skin integrity.8 This is an
important limitation because Paul et al, (2011) described tissue
contracture as a result of treating subcutaneous collagenous
tissue, rather than dermal collagen only.9 Subcutaneous collagenous
tissue includes the papillary and reticular layer of the
dermis; fascia layer between muscle and skin; septal connective
tissue segmenting fat lobules and linking the dermis and
fascia; and reticular fibers encapsulating adipocytes.8
A treatment strategy that may deliver the appropriate
subcutaneous heating for optimal skin contracture is thermistor-
controlled subdermal skin tightening (ThermiTight) via
