OBSERVATIONS, DATA, COMPARISONS, DISCUSSION
Current Status of Glottic Injectables
From May 1 2004 Meeting (Scottsdale)
Many excellent
contributions were made to the Study Group by the following presenters:_Mona Abaza (with Ingo Titze), Gerald Berke, Jamie Koufman,
Murray Morrison, Claudio Milstein (with Marshall Strome), Clark Rosen, and Andy Blitzer. Several have asked me for a summary of the Study
Group, some members who were present, and others who couldn’t
make it. (please note that I’ve included some hyperlinks for
further information).
Here are some of
the highlights of our meeting.
Mona Abaza
MD
Drs Abaza and Titze presented data from a study comparing CyMetra and
two forms of hyaluronic acid. We
had asked them to describe characteristics of the “idea” glottic injectable. Their
data showed that that the desired viscosity varies with
pitch, and accordingly no single injectable substance
fits all criteria.
Gerald Berke
MD
(commented on Collagen
[Zyderm,Zyplast]
and a Hyaluronic Acid preparation – Hylan-B
Gel). With respect to collagen vocal fold injection,
Dr. Berke uses Zyplast because it is cross-linked. He
does not routinely skin test patients, reasoning that the
larynx is a much less immunoreactive organ
than is the skin. He has seen only one reaction to the
material in over 1,000 patients. Zyplast costs
approx $100/cc, and comes from Inamed in
pre-packaged tuberculin syringes. It can be injected through
needles as small as #30. Dr. Berke noted that in many
patients only one injection is needed, despite the fact
that Zyplast undergoes
absorption/degeneration over several months. It is possible
that Zyderm has a lower viscosity
than Zyplast, and hence Zyderm might
conceivably be more suitable for submucosal superficial
injection into the superficial lamina propria (SLP),
as opposed to the deeper injection of other injectables.
An
animal study of Hylan-B Gel was reported
to the ALA (authors,
Berke and colleagues Jahan-Parwar, Chhetri, et al) as restoring
mucosal waves scarred by CO2_laser
injuries. The gel is injected superficially into the SLP. Dr.
Berke has had successes as well in human patients, and
feels that Hylan-B has promise as
a superficial glottic injectable substance. It is supplied in a 1 cc tuberculin
syringe, similar to Zyplast. The material is a relatively pure form of hyaluronic acid derived from combs of specially bred roosters. Trade
name Hylaform,
Inamed Corp. (recently_FDA approved for subcutaneous
injections)
Other hyaluronic acid producs were
discussed by other presenters, including Murray Morrison. Restylane, Perlane are
other hyaluronic acid products which are being used for dermatological
and cosmetic
injections. Of these two Perlane has a larger particle size
and arguably could be better suited for deeper vocal fold
injections (lateral to
vocal ligament) whereas the lower viscosity Restylane and Hylan-B
gel could be more suitable for superficial SLP injection.
In
closing Dr. Berke commented re: fat injection, saying that
he does not favor fat injections, because the fat doesn’t
last a year, and probably much less.
Jamie Koufman
MD
disagreed with Dr. Berke, saying that in her experience
and practice, glottic fat injection has
performed nicely. Dr. Koufman
outlined the technique of harvesting fat with a small
bore liposuction cannula, and washing the fat
with albumin.
The fat is injected
through a Bruning injector utilizing a #19 needle.
Claudio
Milstein MD & Marshall Strome MD
presented
data from a series of patients having vocal fold CyMetra
injections. CyMetra is micronized Alloderm, and is rather
widely used among laryngologists, for vocal fold injection. One
question has been the duration in vivo following injection. A
quick poll of the study group revealed that most felt that “significant
persistence” of injected CyMetra was less than 4 months,
although data was reported to the contrary (longer
lasting) by these presenters, as
well as Drs. Peak Woo and Natasha Mirza (who has radiographic
data_re: persistence of injected Cymetra)
It
was pointed out subsequently by Dr. Blitzer (see below) that
some dermatologists are expressing dissatisfaction with the
time constraints of having to mix_the
material, and this could have an effect on the company’s success,
which could in turn affect the long-term availability of the
product to laryngologists. CyMetra is injectable through
a small bore needle ( I use a 7 inch #25 spinal needle,
and it can be injected through #27 needles as well.)
Murray Morrison
MD (Radiance)
Vocal cord augmentation via transcutaneous injection of calcium hydroxylapatite has
been performed on a small group of patients with encouraging
results.
The complication rate appears to be
low and the short and medium term results satisfactory. One
other group has also had satisfactory experiences using calcium hydroxylapatite in
20 indiviuals9. General anaesthetic was
used to allow placement.
They also demonstrated minimal inflammatory
reaction in a donated larynx.
Andrew Blitzer
MD
1. Permanent
Filling materials
a. Silicone
b. PMMA
(polymethyl methacrylate)
[Artecol-
PMMA beads in a bovine collagen vehicle- not yet FDA
approved]
c. ePTFE- polytetrafluoroethylene-
[Gortex]
2. Temporary
Filling Materials
a. Collagen
(1)- bovine-[Zyderm, Zyplast—skin test required
1 month before injection]
(2)- human-
[Cosmoderm, Cosmoplast]
(3)- autologous- [ Autologen - expensive- not currently available]
b. hyaluronic acid
gel- (hyaluronins)- glycosaminoglycans-
hydrophilic
(1) avian-
[Hylaform] hylan B-
made from chicken combs
pitfall—some
pts. May have allergy to avian proteins that may contaminate
the material- no local anesthetic
(2)bacterial- =Restylane-
streptococcal bioengineered Hylan B
soon there
will be Restylane fine line (less
viscous) and Perlane (larger particle size due to cross linking-
more viscous- longer lasting)
-Juviderm-
French company- no FDA approval yet.
c. Fascian-
human freeze dried irradiated fascia- no skin test needed-
needs to be reconstituted with saline or lidocaine
d. Cymetra-
cell free collagenous material from human skin- micronized-
must be reconstituted- no skin test
e. Polylactic acid hydrogel-
[ Newfill ]
Immumnologically inert-
40-60 um microspheres- lyophilized
and must be reconstituted
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