The Laryngoscope
Lippincott Williams & Wilkins, Inc.
©
2003 The American Laryngological,
Rhinological and Otological Society, Inc.
LETTER TO THE EDITOR
Ossicle Homografts Revisited
tine use, and is not ototoxic. For the surgeon and the
nurse, such inactivated ossicles imply no changes in sur-
gical technique or ossicle handling.
Dear Editor:
Compared with the successful four-decade record of
ossicle homografts, artificial implants still remain uncer-
tain alternatives with a maximum clinical time horizon of
less than 20 years. Mostly biomechanically completely
different from ossicles, they are not so rarely extruded
from the middle ear in comparison to the proven long-term
For the last 40 years, good functional results at low
cost have made ossicle homografts the most widely used
material for reconstruction of severely damaged middle
1,2
ears. During all this time, no disease transmission as-
sociated with ossicle–homograft implants has been de-
3
scribed in the literature. Ossicle homografts are still
14
suitability of ossicular implants. Moreover, artificial im-
ranked second in the United States for use in middle ear
plants cost hundreds of dollars per piece and thus are
affordable only for patients in industrialized countries
4
reconstruction, according to a recent survey. On the other
hand, the general discussion on human immunodeficiency
virus (HIV) and prion-associated Creutzfeldt-Jakob dis-
ease (CJD) transmission has led to an almost complete
ban on use of homograft ossicles in many countries such as
Great Britain, France, and Germany. Insufficiently inac-
tivated living transplant or dead implant material in-
volves a risk of viral, bacterial, and/or prion disease trans-
mission from donor to recipient. This has been confirmed
by bone-associated but not by ossicle allograft–associated
HIV, hepatitis, and tuberculosis transmission, according
15
with billion-dollar health care systems. How can we
provide otological help to thousands of patients in devel-
oping countries, when the price for the implant alone
exceeds several years’ salary of the patient? An apparent
economic conflict of interest is documented by the vast
choice of artificial middle ear implants emerging on the
market since homografts have been banned.
In conclusion, there is no scientific or clinical evi-
dence that ossicle homograft implants have been respon-
sible for disease transmission during the last 40 years.
The literature and daily practice over a period of decades
evidence the validity of ossicle homografting in middle ear
reconstruction. The guidelines for homografting to be re-
spected compulsorily include a certified organ donor pro-
gram at the hospital, a defined uncomplicated transcanal-
5
to the literature. Moreover, two ear surgery–associated
case reports using untreated non-ossicle material, such as
lyodura and pericard, describe a putative CJD transmis-
6,7
sion. The World Health Organization (WHO) classifica-
8
tion for spongiform encephalopathies grades human os-
sicles as risk class 4 (nondetectable). Implant material for
elective surgery such as ossicle homografts must undergo
safe and effective treatments to inactivate all types of
infection agents and yet maintain optimal preservation to
be eligible for implantation. Today, the most widely (until
recently) used formaldehyde/cialit disinfection/preserva-
tion procedure is obsolete; apparently, it is not only inef-
fective in preventing the sensitive HIV but even commonly
TABLE I.
Ossicle Selection-Harvesting-Inactivation-Preservation Protocol.
9
Donor selection
thought to propagate CJD infections. Based on guidelines
A certified organ donor program guarantees appropriate donor
selection according to established actual guidelines.
dealing with infections, the recommended sterilizing or
inactivating procedures that also inactivate the more re-
silient germs, such as the nucleotide-free putative infec-
tious prions causing CJD, include autoclaving and NaOH
Ossicle harvesting
Human incus and malleus are removed from the intact middle
ear by transcanalicular tympanotomy. Patients with disease or
traumatic temporal bone pathology are not eligible for the
procedure. Neither may isolated temporal bones used for
ossicle harvesting. The ossicles may be kept frozen at Ϫ20°C
for several weeks.
10
11
treatment. We have developed and been using the
SHIP protocol for selection, harvesting, inactivation, and
preservation of human ossicles for ossicle implant pur-
12
poses since 1998 (Table I). According to our in vitro and
Ossicle inactivation procedure
13
in vivo results after the combined NaOH/autoclaving
inactivation procedure, homografts keep their biome-
chanical and clinical properties to an amount comparable
to the formerly used formalin/cialit procedure. No local or
systemic adverse effects or homograft extrusion has been
observed during the operation or during follow-up. The
described protocol is simple, inexpensive, practical for rou-
Complete ossicle immersion in 1N NaOH for 60 minutes at
room temperature. Ossicle rinsing in 1000 mL 0.9% sterile NaCl
solution overnight at room temperature. Ossicle autoclaving for
8
minutes at 134°C.
Ossicle preservation
Ossicles packed under sterile conditions may be kept shelved
for several months.
Laryngoscope 113: July 2003
Letter to the Editor
1
274
Kondakow
