Intralesional Injection Of Keloids And Hypertrophic Scars - Robbins ...

Intralesional Injection of
Keloids and
Hypertrophic Scars with
the Dermo-Jet
CHARLES P. VALLIS, M.D., FA.C.S.* / Lynn,
Massachusetts
The use of steroids in the treatment of keloids and
hypertrophic scars has aroused considerable interest
during the past few years. In 1951 Conway and Stark 1
showed that adrenocorticotropic hormone injected into
keloids relieved symptoms of pain and itching but
caused no apparent improvement in the appearance of
the scar. In 1963 Murray 2 reported the use of
triamcinolone acetonide for the treatment of keloids. He
showed significant improvement by injecting the drug
into the wound margin after surgical excision or
dermabrasion of the keloid. In 1966 Griffith 3 and
Ketchum and associates 4 reported that significant relief
of symptoms and improvement of the appearance of
keloids resulted after the intralesional injection of
triamcinolone acetonide.
However, the injection of the solution into these
scars has presented a serious problem. Keloids and
hypertrophic scars are extremely firm and dense, and
injection of any solution into this type of tissue is
difficult and painful. A prior injection with a local
anesthetic around the scar is often necessary to prevent
the severe discomfort which results from distention of
the scar by the steroid. A series of injections over a
period of several weeks and months are frequently
necessary, making this method of treatment a rather
unpleasant and painful experience to the patient.
Description of the Dermo-Jet
Since November 1965, I have been using a new
instrument called the Dermo-Jet† for the intralesional
injection of keloids and hypertrophic scars. Essentially,
this is a needleless pressure injection syringe for the
intradermal infiltration of drugs in a soluble state. The
Presented at the Annual Meeting of the New
England Society of Plastic and Reconstructive Surgery,
Worcester, Massachusetts, April 15, 1967.
* Instructor in Plastic Surgery, Tufts Medical
School, Boston.
† Distributed by Robbins Instrument Company,
Chatham, New Jersey.
Dermo-Jet was invented by Dr. Alfred Krantz, a French
physician. Unlike other instruments employing the
needleless pressure injection technique, the Dermo-Jet
is a simple, small, relatively inexpensive instrument.
The Dermo-Jet is activated by pressing the
thumb upon the release button, which triggers the
ejection mechanism that unlocks the dry compressed
spring. The spring then drives the plunger with great
force into an ejection chamber charged with 0.1 cc. of
the injectable solution and forces the dosage through the
capillary orifice. No air can be injected. The infiltration
is controlled by four fine wire cloth filters. The Dermo-
Jet technique achieves almost painless tissue infiltration
with a high velocity microspray in single or multiple
doses of 0.1 cc. to a depth of 2 to 5 mm. without actual
contact with the site of injection. A fine jet emitted
under great pressure punctures the tissue without
coring, with a minimum amount of trauma, raising
instantaneously a well-defined pinpoint wheal. Priming
and reloading are done simultaneously by rotating the
jack handle 180 degrees. The transparent chamber has a
4-to 5-cc. refillable capacity (fig. 1A).
The service requirements of the DermoJet are
minimal. The Dermo-Jet may be sterilized by boiling,
autoclaving or dry heat up to 284 0 F. (140 0 C.) or by
immersion in germicidal solutions. Once sterilized, the
syringe contents remain sterile. The DermoJet nozzle is
mounted with a detachable and transparent plastic
spacer (fig. 1A). This replaceable accessory produces
¼-in, nozzle retraction and has an important function as
the injection head positioner and skin stabilizer. Since
only the plastic spacer touches the skin, asepsis for
injecting several patients is obtained by sterilizing only
the spacer in a germicidal bottle or by sponging.
This instrument has proven to be useful for the
injection treatment of keloids and hypertrophic scars. A
series of multiple doses of the steroid solution over the
whole surface of the scar can be done very quickly with
minimal discomfort to the patient. The injections can be
spaced so that the wheals raised by each injection
become confluent with each other. Thus, a controlled
amount of solution can be introduced into every portion
of the scar.
Composition of the Solution
A combination of 5 parts of triameinolone
acetonide (Squibb’s Kenalog parenteral), 40 mg. per
cc., and 1 part of the stabilized solution of
hyaluronidase (Wydase), 150 U.S.P. units per cc., is
used. The efficacy of the intralesional injection of
triameinolone acetonide for the treatment of keloid-type

scars is well documented. I have added the Wydase to
the steroid solution because it appears to cause greater
diffusion of the solution. I also believe that it lessens
the stinging pain which often results after injection of
the steroid. Cornbleet 5 stated that infiltration of the scar
with Hyaluronidase produces softening even of old,
hard keloids and some diminishing in size.
Method of Treatment
The technique is simple and is performed as an
office procedure. Several patients are usually done
simultaneously to prevent wastage of the solution. Only
the plastic cuff on the end of the instrument needs
sterilization between patients. No type of anesthesia is
required. The scar to be injected is sponged off with a
mild antiseptic solution. With each injection by the
Dermo-Jet, a pale white wheal measuring
approximately 1 to 1.5 cm. in diameter is attained. The
injections are spaced so that the wheals from each
injection more or less touch each other and fuse. The
entire scar is injected at one sitting. In the smaller scars
only 1 or 2 injections may be needed. As many as 25 to
30 injections have been done for some of the larger
scars. The instrument is placed vertically over the scar
so that the removable and easily sterilized plastic cuff
on the end touches the scar (fig. 2). Rarely, when there
is a small area to inject, the plastic cuff may obscure the
lesion. Then it is wise to remove it and keep the nozzle
of the instrument approximately ½ cm. above the scar.
After the first treatment is completed, the
patient is advised to return again in 2 weeks, at which
time a second injection is done if necessary. After the
second injection series, the patient is advised to come
back in a month. Many patients do not require more
than 2 series of injections. However, the larger keloids
may require several doses. One had a total of 10 series
of injections spaced about 1 month apart.
For the initial injection it is best to acquaint the
patients with the machine and allow them to hear the
“snap” of the machine before giving the injection.
Many of the younger patients are frightened by the appearance
of the machine and the snapping sound. This
sometimes makes them hypersensitive to the small
amount of pain caused by the injection. By and large,
these patients are much more cooperative for
subsequent injections.
Table I
Location No. of Patients
Left shoulder 6
Arms 6
Anterior chest wall 4
Face 3
Abdomen 3
Thigh 1
Foot 1
Hand 1
Mastoid 1
Neck 1
Back 1
Total 28
Clinical Material
Since November 1965, 28 Caucasian patients
with keloid or hypertrophic scars have received a
combined total of 64 injection series of this mixture of
triamcinolone acetonide and Wydase.
The ages of 22 patients ranged between 6 and
29 years, and the other 6 patients were between 33 and
70 years of age. The average age was 22 years. Seven
were men and 21 were women.
Of the 22 patients in the younger age group, 14
had scars which were considered to be true keloids. All
the scars treated in the older age group were
hypertrophic scars. The locations of the scars are shown
in table 1.
The causes of the scars varied. Of the 14
keloids, 6 were the result of vaccinations, 3 resulted
after surgical excision of benign lesions, I from a burn,
2 from infection due to acne and 2 from injury. Of the
14 hypertrophic scars, 8 resulted from operative incisions,
3 from injuries, 2 from burns and 1 from
dermabrasion on the face. At the time of the initial
treatment of these patients, the lesions had been present
from 2 months to 10 years with an average of 3 years.
A total of 64 series of injections ranging from
1 to 10 were given to the 28 patients. Nine are still
under treatment. A total of 49 series were given to the
completed 19 cases, making an average of 2.6. Of the
28 patients treated, 14 had no symptoms referable to the
scars, and they were primarily interested in improving
the appearance of the scars. In the remaining 14, the
most common symptoms were chronic itching and pain.
Of these 14, 10 were interested in relief of symptoms
and improvement of the appearance of the scars. The
remaining 4 were interested only in relief of symptoms

Clinical Results
Relief of symptoms.
An analysis of the 4 patients seeking only
relief of symptoms proved interesting.
1. A 38-year-old woman had had a hysterectomy
through a lower vertical mid-abdominal
incision 2 years previously. She developed a
raised, hypertrophic, reddish brown scar
measuring 2 in. by 9 in. The scar was
extremely sensitive and painful. She was
unable to wear a girdle or other tight clothing
over the scarred area. The entire scar was
injected with the Dermo-Jet initially, and the
patient had complete relief of symptoms within
48 hr. after the injection. The patient
subsequently had 2 additional series of
injections with complete flattening of the scar
and permanent cessation of the symptoms.
2. A 70-year-old man had had a colon resection
through a lower vertical mid-abdominal
incision 10 months previously. He developed a
raised, painful, hypertrophic, reddish brown
scar measuring % in. by9 in. This patient also
had complete relief of symptoms after the
initial injection. He subsequently had 2
additional series of injections with complete
flattening of the scar.
3. A 42-year-old woman had a similar raised
hypertrophic scar on the right flank resulting
from a nephrectomy operation 18 months
previously. This patient was very apprehensive
and had been under psychiatric care for a
depressed state. This scar measured 3/8 in. by
8 in. Her symptoms were relieved after 2 series
of injections. A major portion of her scar was
flattened. This patient was one of a few who
complained of severe pain during the injection
and also persistent burning pain for several
hours after the injection.
4. A 19-year-old girl complained of severe pain
to pressure over a small localized area of
subcutaneous scarring on the sole of the left
foot following removal of a plantar wart 2
years previously. This patient had 1 injection
with the Dermo-Jet. The scar softened and
completely disappeared with cessation of
symptoms within a month after treatment.
Of the other 10 with symptoms, 9 had
complete relief of symptoms within 48 hr. after the
initial series of injections. The remaining patient was a
33-year-old woman with multiple hypertrophic scars on
the palm of the left hand resulting from a crush injury 5
months previously. She had 5 series of injections with
softening and leveling of the scars and marked
improvement of symptoms. She still complained of
moderate pain to pressure over a tight scar on the
proximal crease of the palm.
Appearance of the scar
Analysis of the appearance of the scars after
injection indicated a very favorable response to the
therapy. Nine patients are still under treatment. Of the
remaining 19 patients, 14 had complete leveling of the
keloid or hypertrophic scars. Of the 14, 4 were small
keloids averaging 1,4 in. in diameter resulting from
vaccination. The other 10 were hypertrophic scars
resulting from surgery or injury. Of the 5 of the 19 who
showed incomplete leveling of the scar, 2 had 80 to 90
per cent leveling.
1. The patient was a 17-year-old girl with a large
recurrent keloid on the left shoulder measuring
2½ in. in diameter. It was of 3 years’ duration
and resulted from the surgical excision and
graft of another keloid resulting from
vaccination. X-ray therapy was also given at
the time of the surgical excision. She had a
total of 8 series of injections over a period of
10 months.
2. An 18-year-old boy had a keloid over the left
mastoid area resulting from a car accident. The
scar measured 3/8 in. by 1 in. He had a total of
3 series. Three showed a 60 to 75 per cent
leveling of the scar.
3. A 21-year-old man had multiple keloids on his
chest resulting from acne. He
had a total of 7 series of injections.
4. A 42-year-old woman had a hypertrophic scar
on the right flank following a nephrectomy.
She had a total of 2 series of injections.
5. A 14-year-old boy had a large keloid on the
left side of the neck resulting from injury. He
had had a surgical excision with Z-plasty
repair 1 year previously with marked
recurrence of the keloid which measured 1 1/2
in. by 5 in. He had a total of 10 series of injections
over a period of 12 months with about
75 per cent flattening of the scar.

Pain experienced during and after injection.
The Dermo-Jet has proven itself to be a very
useful instrument in the injection treatment of keloid
and hypertrophic scars primarily because of the ease of
administration. of the drug. No form of anesthesia is
necessary with the Dermo-Jet.
A controlled amount of solution is given with
each injection, and there is visible evidence in the form
of pale white wheals to indicate whether the entire scar
has been injected. An analysis of the amount of pain
resulting from the injections with the Dermo-Jet proved
interesting. I have used this instrument on myself and
some of my fellow workers. The pain noted during the
injection into normal skin on the arm was minimal and
insignificant. It felt like a tiny transient “pinch” in the
skin. There was no after pain.
Of the 27 patients treated, 18 complained of
minimal or insignificant pain during the injection. Most
stated that it felt like a tiny mosquito bite, and they
were able to tolerate several injections during each
series without any complaint. Six complained of
moderate pain with the initial series of injections. They
described it as a momentary sting. They were also able
to tolerate multiple injections, and most of them had
minimal pain with subsequent injections. Three
complained of severe pain during the injection.
1. A 21-year-old girl had a large keloid burn scar
of the right cheek of 7 months’ duration. This
patient had had a total of 6 previous Kenalog
injections with a needle and syringe and also
radiation therapy elsewhere. She was
extremely agitated, and treatment had to be
suspended after only a few injections with the
Dermo-Jet. When this patient returned for her
second treatment 1 month later, 1 part of 2 per
cent Xylocaine was added to the 6 parts of
Kenalog and Wydase. She was assured that the
pain would be negligible, and she was able to
tolerate about 15 injections with only minimal
to moderate complaints of pain.
2. A 42-year-old maiden lady had a painful
hypertrophic scar on the right flank 18 months
after a nephrectomy. She had been under
psychiatric treatment for a chronic depressed
state. This patient stated that the injection
caused a sharp painful stinging sensation.
However, she did tolerate 5 injections with the
first series and then came back a month later
for a second series at which time she had 10
injections. This patient also complained of
persistent stinging pain in the scar for several
hours post injection.
3. A 10-year-old boy had a large recurrent
hypertrophic scar on his left arm measuring 1
in. by 6 in. This boy had had 2 previous
operative procedures for gradual partial
excision of a much larger scar. He complained
of severe pain during the multiple injections.
He returned 1 month later for a second series
of injections. Again, 1 part 2 per cent
Xylocaine solution was added to 6 parts of
Kenalog and Wydase, and this time he
tolerated the treatment with minimal complaints
of pain.
Rees 6 has tried the Dermo-Jet for injecting
Kenalog solution into hypertrophic scars, and he has
noted that his patients have complained of very severe
sensations of pain and burning in the scar for several
hours following treatment. In fact, he has found it more
painful than direct injection by needle. My experience
has shown that the great majority of patients complain
of minimal pain. I believe that the addition of the
Wydase markedly lessens any post injection pain. The
addition of a small amount of local anesthetic to the
Kenalog solution would also diminish any post injection
pain in patients who complain initially. Reassurance of
these patients and their acquaintance with this
instrument before treatment help considerably in minimizing
any discomfort.
Discussion and Summary
This paper has been principally written to
acquaint the medical profession with a useful new
instrument, the Dermo-Jet. The DermoJet has been
employed for the intralesional steroid injection of
keloids and hypertrophic scars in a total of 28 patients.
A definite improvement evidenced by disappearance of
the symptoms and leveling or flattening of the scars was
noted in all cases. Some scars showed a faster and more
spectacular response than others. The most dramatic response
was noted in the hypertrophic scars resulting
from surgery or injury. Complete flattening of these
scars resulted after only 1 to 4 series of injections.
The true keloids, especially the larger ones, showed a
slower response. Softening and flattening proceeded
slowly, and a large number of doses were needed over a
longer period of time. The small keloids resulting
from vaccination showed a quick, dramatic response to
only 1 or 2 series of doses.
In the hypertrophic operative scars of the
abdomen, the principal complaint was burning pain and

itching. In these patients, contact of their clothing over
the scar caused discomfort. It was gratifying that their
symptoms were quickly relieved after just a few
injections.
Most patients experience minimal pain when
the solution is injected into the scar. They tolerate the
procedure well without the need for any type of
anesthetic. Most of the patients have some
apprehension with the first series of injections.
However, subsequent injections are taken with minimal
discomfort. The few who complained acutely during the
initial injection tolerated subsequent ones quite well.
This method of treatment is not being
proposed for all scars that come to a surgeon’s
attention. In many patients, surgical excision, when
indicated, is still the quickest and most efficient form of
treatment. Intralesional injection of steroids into a
raised scar will level the scar and smooth it out but it
will not narrow it. This technique does not replace the
tried and proven techniques of the plastic surgeon. It
should be used as an aid to surgery to be done when the
surgeon begins to notice even the slightest recurrence of
hypertrophy or keloid formation after surgery. In
known keloid formers who are undergoing surgery, the
technique of Griffith’ of injecting Kenalog with a
regular syringe into the wound at the time of the
surgery appears to have merit. Intralesional injection
could also be used for most true keloids when the
surgeon feels that surgery would be of no avail. This
method may be used in cases that have already had a
surgical attempt at correction. It has proven to be
especially effective in patients who are more concerned
with the symptoms caused by the scar than with the
appearance.
Other Uses of the Dermo-Jet for the Plastic
Surgeon
There are a number of situations in medicine
where the Dermo-Jet has already proven itself quite
useful, e.g., in mass vaccinations. I have found it very
useful in removing plantar warts under local anesthesia.
The Dermo-Jet is used for the subtopical injection of a
local anesthetic. Greater depth can be achieved by
inserting a needle with additional anesthetic solution
painlessly into the wheal center. I have also been
exploring the possibility of the intralesional injection of
the plantar wart itself with a solution that would result
in resolution of the wart.
Another possible use of the Dermo-Jet which I
have also been considering is the injection of a
sclerosing solution into some of the smaller raised
hemangiomas. Its use in the larger hemangiomas would
be limited since the scierosing solution would not penetrate
more than 5 to 6 mm.
Conclusion
The Dermo-Jet, a needleless pressure injection
instrument, has proven to be of great value for the
intralesional injection of keloids and hypertrophic scars.
The technique is simple and quick with minimal
discomfort to the patient.
41 Ocean Street
Lynn, Massachusetts 01902
REFERENCES
1. Conway, H., and Stark, R. B.: ACTH in plastic
surgery. Plast. & Reconstruct. Surg., 8: 354— 377,
1951.
2. Murray, R. D.: Kenalog and the treatment of
hypertrophied scars and keloids in Negroes
and whites. Plast. & Reconstruct. Surg., 31:
275—280, 1963.
3. Griffith, B. H.: The treatment of keloids with
triamcinolone acetonide. Plast. & Reconstruct.
Surg., 38: 202—208, 1966.
4. Ketchum, L. D., Smith, J., Robinson, D. W., and
Masters, F. W.: The treatment of hypertrophic
scar, keloid and scar contracture by triamcinolone
acetonide. Plast. & Reconstruct. Surg., 38: 209—
2 18, 1966.
5. Cornbleet, T.: Treatment of keloids with hyaluronidase.
J. A. M. A., 154: 1161—1163, 1954.
6. Rees, T. D.: Personal communication.