Lasers were a technological breakthrough in
medicine for a variety of reasons. The different types
of lasers possessed very “feature-specific” properties
– the most important being that they existed at a fixed
wavelength of light and in so doing would only be
absorbed by certain equally specific constituents of the
human body.
An example of this would be the potassium-titanyl
phosphate laser (KTP), a “green-light laser” that had
properties which would be specific to substances that
were in the red band of the spectrum of visible light. The
commonest example of such a substance would be the
molecule called haemoglobin found in blood that gives
it its redness. Haemoglobin would better absorb the
light energy from the KTP laser compared to plain water
which is colourless.
Therein lay the potential for selective uses of laser
energy in the body – from skin (pigmented moles, scars,
loose skin, cancers) to tumours in the mouth, nose and
throat and even stones in the salivary ducts (and in
the case of urologists – within the kidney, ureters and
bladder – the Holmium- YAG laser).
The CO2 laser has come a long way from its first
experimental use on dogs in the early 1970s. The
seminal work by Drs Jako and Strong at Tufts University
in Boston, US, which paved the way for laser surgery of
the voice box and throat – cruder then when compared
to now – was an engineering marvel providing the
precision tool to cut, ablate and penetrate according to
the indication it was used for.
It has become a workhorse in the treatment of
tumours of the voice box and is used by surgeons to
treat snoring and help in the management of sleep
apnoea. While originally designed to be applied/fired in
a straight line given its long and “unwieldy” wavelength,
it is now manipulated by a joy stick akin to a computer
game with the added benefit of magnification by an
operating microscope. Flexible fibre delivery – designed
in the late 20th century – has allowed the surgeon to
utilize the CO2 laser with flexible fibre endoscopes in
awkward locations like the middle ear, tongue base and
nose.
It is now quite common in several centres across the
world that patients are awake and locally anaesthetized
while the scope and laser fibre are inserted and applied –
something that would have been impossible a generation
ago. Minimally invasive surgery is progressing at a pace
that would have been inconceivable five decades ago,
with advances in optics, lasers, diagnostics, robotics
and computer-aided therapeutics.
Robots
When Leonardo da Vinci dreamt of his Automa
cavaliere (Automaton knight) over five centuries
ago, little did he realise that his invention would be
remembered as the Robot di Leonardo and inspire the
creation of similar automatons that would help humans
perform tasks in a pre-programmable fashion across
diverse settings such as the motorcar manufacturing
industry to medicine.
The term robot, however, was coined by the brother
of Czech playwright Karel Capek who used it in his
GlobalHealthAndTravel.com
play Rossum’s Universal Robots. The meaning of robot
was essentially “servitude” and had its origins from the
Germanic for “work” – arbeit.
Modern medical robotics took off in the early 21st
century. The essential difference in the application of
medical robots compared to industrial ones was one
of complete independence from human interference/
control to one where the robot “operator” remained in
control of all functions regarding the surgical procedure.
The debate that surrounds this term “robot” in the
surgical context is thus one where the current robots
used in otolaryngology are really manipulators and not
independent machines with algorithmic programming to
substitute the surgeon’s decision-making and skill.
Current robotic technology in ENT is mainly limited
to two platforms – the da Vinci Surgical System
(Intuitive Surgical Inc, Sunnyvale, California, US) and
the Medrobotics Flex system (Medrobotics Raynham,
Massachusetts, US). Both systems provide the surgeon
with access to the upper aerodigestive tract through
the mouth. The da Vinci system is a rigid, line-of-sight
system incorporating a camera arm with high definition
visualization and illumination while two other instrument
arms are inserted into the mouth to manoeuvre, dissect,
cut and coagulate tissue.
The system has allowed head and neck surgeons
to access the back of the mouth and tongue – areas
generally difficult to operate, given the contours of the
mouth, throat and back of the voice box (larynx). As a
result, patients undergoing radical and often mutilating
procedures requiring splitting of their jaw to remove
cancers from their tonsils, palate and tongue base
with further plastic surgical reconstruction can now be
successfully treated without the need to perform such
extensive surgery.
The results of these operations are equally good
compared to the more radical open operation but the
quality of life after the operation is better with shorter
lengths of stay in hospital. The Flex system is effectively
a hybrid of a flexible endoscopic platform which is
controlled using a manipulator and a rigid camera
with side-arms allowing for grasping, cutting, laser
transmission and dissection and resembles a multi-
linked “snake”. The major differences between the two
systems reside in the fact that the “Flex” was designed
specifically for the needs of head and neck surgery
(initially) while the da Vinci system has a wider field of
application.
It is particularly useful given its flexibility to negotiate
the areas behind the tongue and can enter the voice box
and upper oesophagus. Lasers and robots are alternatives
to providing precision and access to the complex and
challenging anatomy of the upper aerodigestive tract. With
more features such as high-definition video, illumination,
image guidance and anti-tremor filtering, the march of
technology continues unabated.
Dr Vyas MN Prasad
Senior Consultant
Otolaryngologist; Head
& Neck Surgeon
MB BCh BAO BA
(Dublin), MSc DIC
(London), DLO
(England), MRCS (Edin),
FRCS(ORL – HNS)
(Edin), FICS
For enquiry or appointment, call +65 6931 8000
Visit us at:
MWH Medical Specialists Centre, 101 Irrawaddy Road,
#07-01 Royal Square Medical Centre
Singapore 329565
MARCH 2020
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