As we go through our practice years, one of the things we all
strive for is to make our lives less stressful. For those of us doing
surgery many times per day, this is essential in order to maintain
our sanity. Doing surgery is stressful enough as it is. Having to
deal with surgical complications is something I like to avoid. As
I have taught in my courses and on the message boards of
Dentaltown.com, one of the best ways to deal with complications
is to prevent them from occurring in the first place. This
involves very simple strategies that can make a big difference.
Why look for trouble?
One of the most dramatic complications we see in dentistry
is the development of subcutaneous air emphysema.* A
relatively uncommon phenomenon, subcutaneous air emphysema
has been reported in both medical and dental literature
for such varied procedures as rectal biopsy, nasogastric intubation,
radical neck dissection, tonsillectomy, adenoidectomy,
root canal treatment, dental restorations and extraction of
maxillary and mandibular teeth. The most common cause
involves the surgical extraction of mandibular third molars. It
is a result of air under pressure being driven into the subcutaneous
tissues in the head and neck. It is generally associated
with the use of a high-speed, air-driven dental handpiece,
which allows air to be vented toward the bur. This air under
pressure can get into the subcutaneous tissues when either a
flap is reflected or the gingival attachment to the alveolus is
compromised. Air is forced beneath the dermis, and subcutaneous
air emphysema results.
More commonly, air is also forced into the fascial planes,
causing tissue space emphysema. Due to many of the fascial
spaces of the head and neck being contiguous, retropharyngeal
and mediastinal emphysema are possible sequelae of air
getting into the soft tissues surrounding the oral cavity. The
severity of this disease is variable. In some cases, the swelling
is minor and localized, necessitating only reassurance to the
patient that the condition is benign, self-limiting and temporary.
In more severe cases, antibiotics, close observation, hospital
admission and surgical intervention might be indicated.
It is important for the clinician to be able to recognize subcutaneous
air emphysema when it occurs, so that inappropriate
therapies can be avoided. A sudden facial swelling occurring
during a dental procedure involving pressurized air or air turbine
instruments is characteristic. Pain on palpation and a
sensation of being able to move air within the tissues and
crepitance, not associated with an underlying bony defect, are
important features in the diagnosis of subcutaneous emphysema.
Definitive evidence of this condition is obtained by
radiographs of the soft tissue, which show masses of free air
within the layers of soft tissue.
To prevent air emphysema you should be using a surgical
rear-venting handpiece whenever you do any type of surgical
procedure. I have been told by a number of non-oral surgeons
that since this happening is so rare, it is not worth worrying
about. But, for anyone who does surgical extractions or bony
surgery at all, the minimal investment will give you significant peace of mind, and essentially eliminate the occurrence of this
stress-inducing complication. This is a fairly rare phenomenon,
but it does occur. In my 20+ years of private practice experience,
I have seen a total of four cases, as well as one during my oral
surgery residency. You, most likely, will see a case or two in your
career. When it develops, it is quite rapid and quite dramatic. It
is very stressful for both patient and dentist alike, but is completely
preventable by simply changing which handpiece is used
when you are doing surgical extractions.
The most common etiology is from using a standard highspeed
dental handpiece to perform a surgical extraction or periodontal
surgery. This type of instrument, which is normally used
for restorative procedures is designed to deliver a stream of water
and compressed air to the operative field to prevent excessive heat
generation of the tooth being treated. It also vents a portion of the
air used to drive the turbine forward along the shaft of the bur.
This design is hazardous when used where soft tissue flaps are
raised to surgically extract a tooth. Subcutaneous air emphysema
is associated with the use of an air turbine-driven dental handpiece
when used for surgical procedures and when there is compromise
of the gingival attachment. Clinicians should be
cautioned against use of these instruments for surgical extraction
of teeth and for other surgical procedures where a flap is raised, as
they are not designed for this purpose. Surgical handpieces, which
vent air toward the back of the handpiece, should be used for this
purpose. An electric handpiece can be used as long as the chip
blower is turned off, so that no air blows into the surgical site.
Although surgical extraction of an impacted mandibular
third molar tooth is the most commonly reported cause of
subcutaneous air emphysema, the phenomenon has also been
reported after procedures that did not include a soft tissue
flap. It has also been reported to occur in association with post
and core preparation of a maxillary anterior tooth, crown
preparation of a mandibular third molar, and during
endodontic therapy of a mandibular premolar. It has also been
observed with the use of an air-water jet polishing device for
periodontal therapy, an ultrasonic scaler, and with a standard
dental air-water syringe.
The most common sequelae of subcutaneous air emphysema
are facial swelling and severe pain. However, the spread of air
forced into the fascial spaces can result in more severe consequences.
Respiratory distress can result from retropharyngeal air
which causes restriction of the upper airway. Clinicians should
be to able recognize soft tissue emphysema in a patient by sudden
onset of swelling during a dental procedure and crepitus
within the soft tissues. To avoid this clinical condition, most oral
surgeons use a straight surgical handpiece, which is either electric,
or driven by nitrogen gas which exhausts to the rear. The
reason they run off of nitrogen is that the handpiece is a completely
sealed unit, and the oxygen content in compressed air
would oxidize the metal on the inside of the handpiece.
Nitrogen does not do this. These handpieces run at about
100,000 RPM and put out a high amount of torque. Such
instruments run about $3,000 to $5,000, and unless you do a
lot of surgery, they are not really cost effective.
A much better solution for most general dentists and occasional
surgeons is to use a surgical handpiece that has been
designed to attach to a standard dental unit. My favorite handpieces
in this category are the Sabra 45 and 105-degree models
with fiberoptics. The ImpactAir is also a good choice. These
resemble a standard air-driven dental handpiece, but exhaust to
the rear, away from the surgical field. They run at 400,000 to
500,000 RPM and deliver a higher torque than a standard dental
handpiece, so are extremely capable of removing bone and
sectioning teeth as necessary for surgical extractions. They are
nearly the same price as a standard operative handpiece, about
$500 to $700. Unless you are doing multiple surgical extractions
per day, my recommendation is to go with this type of handpiece.
It is not worth taking the risk of a patient developing subcutaneous
air emphysema; using a standard dental handpiece is
just asking for trouble.
The treatment of subcutaneous and tissue space emphysema
varies with the severity of the condition and the experience
of the clinician. Prophylactic antibiotic coverage is
indicated in all cases, as secondary infection is always a possibility,
and finding purulent matter with the swelling has been
reported. Penicillin is a logical choice, as any bacteria involved
in a secondary infection will most likely be of the oral flora.
Some clinicians advocate the use of broad-spectrum antibiotic
coverage on the assumption that air which penetrates the subcutaneous
layers is contaminated. Application of moist heat to
the area may also be helpful. In very mild cases, clinical observation
is the only treatment necessary. It is important to
explain to the patient the nature of the swelling and the
expected clinical course, and to notify the doctor immediately
in case of any increased swelling or respiratory difficulty. In
cases of more severe swelling, lateral and anteroposterior soft
tissue radiographs of the neck should be taken to evaluate the
airway and the extent of the emphysema. Chest radiographs
should also be taken to rule out mediastinal involvement.
Admission to the hospital for observation is warranted, especially
if the patient complains of any airway or throat tightness.
Because of the extreme discomfort that may be
associated with swelling in the neck, the patient's oral intake
of fluids might diminish. Therefore intravenous fluids might
be needed to prevent dehydration. Surgical drainage of
infected tissue should be done if indicated by clinical examination
and by the patient's progress. Most cases of subcutaneous
and tissue space emphysema will begin to resolve after
two to three days of supportive therapy. Residual swelling is
usually minimally evident after about a week to 10 days.
*Over the years I have heard number of terms used erroneously to describe this condition. So, I want to reemphasize for everyone that the correct term for this condition
is subcutaneous air emphysema. This is defined as any abnormal distention of an organ or part of the body with air or gas. The origin of the word is from
the Greek meaning "to blow as a result of action." This condition is not termed an air embolism. An embolism is an obstruction of the circulatory system caused
by a loose blood clot or thrombus or an air bubble. It is also not an empyema. An empyema is a collection of pus that is confined in an anatomical space by normal
epithelial boundaries. And finally, it is not an empanada, which is a Spanish or Latin American turnover with a flaky crust, and spicy or sweet filling.
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