Malleus ankylosis: a rare cause of
conductive deafness
Two cases report
Darbi A, El kharras A, Semlali S, Amil T,
Chaouir S, Benameur M, Bassou D
Radiology department, Military Hospital
Mohammed V. Rabat - Morroco
Introduction
¾
¾
¾
¾
¾
Malleus ankylosis is an unusual cause of conductive hearing loss
who predominates at the woman .
Recognized causes of malleus ankylosis include infection,
trauma, or previous middle ear surgery, although some cases
lack such a history.
It’s usually attributed to a congenital pathology, although it may
be encountered in a middle ear without evidence of congenital
deformity.
Its research must be systematic in all ears being explored for
conductive hearing loss
CT permits the diagnosis easily. The authors present a two
cases explored by CT
Materiel and methods
Case 1
„
„
„
„
40 YOW
Bilateral transmission deafness associated with tinnitus
Otoscopy: normal tympanic membrane
Audiometrical evaluation : bilateral hearing impairment
CT :
„ Bilateral fixation malleus head by calcified anteriormalleal ligament (Fig.1, Fig.2)
„ No other abnormalities of the middle or internal ears.
Fig. 1- axial temporal CT of the right ear : fixed malleus head
by calcified anterior malleal ligament (arrow).
Fig.2: axial temporal CT of the left ear: fixed malleus
head by calcified anterior malleal ligament (arrow).
Case 2
„
„
„
„
60 OYW, without antecedents
Bilateral conductive hearing loss.
Otoscopy: normal tympanic membrane
Audiometrical evaluation :bilateral hearing impairment
CT:
„ Bilateral fixation malleus head to the anterior tympanic
wall by calcified anterior malleal ligament. (Fig.3)
„ Bilateral malleus/incus fixation (Fig. 4).
„ No other abnormalities of the middle or internal ears.
Fig.3- axial temporal CT of the right and the left ears: bilateral
fixation of malleus head by calcified anterior malleal ligament
R
L
Fig.4- axial temporal CT of the right (a) and the left ears:
bilateral malleus/incus fixation (arrows)
DISCUSSION
„
The Fixed Malleus Syndrome first described by Toynbee in
1860 is an unusual pathology, typically presents with conductive
hearing loss with a normal tympanic membrane.
„
Its incidence is lower to 2%, but increases at the time of
revision surgery for otosclerosis.
„
A different types of fixation are possible:
¾
¾
¾
¾
¾
bony ankylosis of the malleus to the epitympanum,
fixation of the malleus by a ligamentous ankylosis to the epitympanic
wall,
isolated incudo-mallear joint ankylosis,
malleus ankylosis to the tegmen ,
fixation of the malleus by an osseous connection to the posterior wall of
the external ear canal.
Etiopathogenesis
„
„
„
Numerous etiopathogenic hypotheses have been suggested in the
literature: otosclerosis, chronic middle otitis , head trauma but
also without any apparent cause.
Congenital abnormalities have a great part in these
etiopathogenic hypotheses; the fundamental cause of malleus
fixation seems to be a lack of development of the epitympanic
space leaving the head of the malleus and the head of the ineus
in close contact with the tegmen.
Primary malleus ankylosis appears to result from ossificatition of
the superior or anterior tympano-malleolar ligament. This
condition occurs in elderly patients and is combined with varying
degrees of sensorineural presbycusis. The association with an
incus fixation, which is rare, may be explained by a concomitant
arthritis of the incudo-mallear join (case 2)
Preoperative diagnosis
„
„
Preoperative clinical diagnosis is difficult. The conductive hearing
loss has not been well characterized, measurements of umbo velocity
and air-bone gap can enable one to diagnose malleus fixation and
specifies how to differentiate malleus from stapes fixation.
It seems possible to suspect an incudo-mallear fixation on the
audiogram when the following features are present:
¾
¾
¾
¾
„
Unilateral mixed hearing loss, usually nonprogressive
Small air-bone gap, predominantly in the low frequencies
Association with a sensorineural impairment in the high tones
Acoustic reflex absent on the impaired ear but present on the contra-lateral
ear.
The CT permits to advance the diagnosis while showing the fixing
and evaluate the status of the ossicular chain.
Case 1- CT of the right ear,
axial slice: fixation of
malleus head by calcified
anterior malleal ligament.
Case 2- CT of the left ear,
axial slice: malleus/incus
fixation .
Treatment
„
Decision for surgical treatment is depends on
audiological findings and potential hearing gain.
„
A common technique involves removal of the incus
and head of the malleus and reconstruction with an
incus interposition or a partial ossicular prosthesis.
„
A new technique proposed by Seidman and Babu is
maintenance of the normal anatomy and use of the
potassium-titanyl-phosphate laser and drill to free the
ossicles and widen the epitympanum.
Conclusion
„
„
„
„
„
The Fixed Malleus Syndrome can be caused by various
disorders or diseases;
Preoperative clinical diagnosis is difficult: conductive
hearing loss has not been well characterized.
Measurements of umbo velocity and air-bone gap can
enable one to diagnose malleus fixation and specifies
how to differentiate malleus from stapes fixation.
CT permits to advance the diagnosis while showing the
fixing and evaluate the status of the ossicular chain.
Surgical treatment is dependent on the audiological
findings and the potential hearing gain.
References
1.
2.
3.
4.
5.
Nakajima HH, Ravicz ME, Rosowski JJ, Peake WT, Merchant SN .
Experimental and clinical studies of malleus fixation. Laryngoscope. 2005,
Jan;115(1):147-54.
Seidman MD, Babu S . A new approach for malleus/incus fixation, no
prosthesis necessaryn. Otol Neurotol. 2004, Sep;25(5):669-73.
Kawano H, Ohhashi M, Nakajima M, Tsuboi Y, Komune S. Surgery for
tympanosclerotic stapes fixation accompanied by malleus fixation at the
anterior malleus, report of 2 cases. Nippon Jibiinkoka Gakkai Kaiho.
2004, Nov;107(11):1011-4.
Vincent R, Lopez A, Sperling NM. Malleus ankylosis. a clinical,
audiometric, histologic, and surgical study of 123 cases. Am J Otol. 1999,
Nov;20(6):717-25. :
Moon CN , Hahn MJ. Primary malleus fixation, diagnosis and treatment.
Laryngoscope. 1981, Aug;91(8):1298-307