Helical CT Findings in Patients Who Have Undergone Stapes ...

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Helical CT Findings in Patients Who Have Undergone
Stapes Surgery for Otosclerosis

Marc T. Williams1, Denis Ayache2, Monique Elmaleh1, Françoise Héran1, Pierre Elbaz2, Jean-Daniel Piekarski1

P rogressive conductive hearing loss yields high-resolution reformatting in oblique Surgical Procedures
is the major clinical symptom of planes along the main axis of the prosthesis, The surgical procedure consists of removal
otosclerosis, which causes stape- allowing a more accurate depiction of the
diovestibular ankylosis (Fig. 1). The aim of prosthesis status, which is helpful for plan- of the stapedial arch followed by the insertion
stapes surgery is to restore hearing in patients ning the surgical revision. In this pictorial es- of a prosthesis [5] (Fig. 2A). The lateral end of
with otosclerosis. Successful surgical results are say, we present CT findings in patients with the prosthesis is bound to the long process of
observed in more than 90% of patients with this unsuccessful stapes surgery. the incus; its medial end transmits the sound
technique [1]. However, unsuccessful outcomes vibrations to the perilymphatic fluid through
or rare surgical complications are observed and Fig. 1.—Incremental axial CT scan at
may lead to a surgical revision. Two major indi- level of oval window in 54-year-old
cations of unsuccessful surgery are seen. The woman with bilateral conductive
persistence or recurrence of a conductive hearing hearing loss caused by otosclerosis
loss is mainly related to the following condi- shows otosclerotic focus as ill-de-
tions: prosthesis displacement, necrosis of the in- fined hyperdense area (arrow ) at an-
cus, postoperative intratympanic fibrosis, terior margin of oval window and
obliterative otosclerosis, malleoincudal disloca- anterior part of stapes footplate.
tion, and ankylosis of the malleus to the tym-
panic walls. Occurrence of vertigo or fluctuating
sensorineural hearing loss is suggestive of an in-
travestibular protrusion of the prosthesis, a peri-
lymph fistula, or a reparative granuloma in the
oval window.
Conventional CT has been used for several
years in the exploration of these symptoms [2–
4]. However, this technique is limited by the
obliquity of the prosthesis relative to the con-
ventional scan planes. Conversely, helical CT

Received May 17, 1999; accepted after revision July 15, 1999. 387
1Department of Medical Imaging, Fondation Ophtalmologique Adolphe de Rothschild, 25 rue Manin, 75940 Paris, France. Address correspondence to M. T. Williams.
2 Department of Otorhinolaryngology, Fondation Ophtalmologique Adolphe de Rothschild, 75940 Paris, France.
AJR 2000;174:387–392 0361–803X/00/1742–387 © American Roentgen Ray Society

AJR:174, February 2000

Williams et al.

Downloaded from www.ajronline.org by 50.116.19.84 on 03/11/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved Fig. 2.—Drawings show principles of surgical treatment
of stapedovestibular otosclerosis.
A, Removal of stapedial arch after incudostapedial disar-
ticulation. Otosclerotic focus is left in place.
B, Stapedectomy with graft interposition. Stapes foot-
plate is completely removed. Oval window is sealed by a
graft. Lateral ring-shaped end of prosthesis is bound to
long process of incus. Medial end of prosthesis is set
against graft and transmits vibrations to perilymphatic
fluid.
C, Small fenestra stapedectomy with graft interposition.
Fenestration is created in stapes footplate and sealed by
graft. Prosthesis is then inserted as described in B.
D, Small fenestra stapedectomy without graft. Small cir-
cular fenestration is performed in footplate. Fenestration
is then sealed directly by medial end of prosthesis.

AB

CD

Fig. 3.—Coronal CT scout image in 51- an opening made in the stapes footplate. Two
year-old man shows correct plane for ob- alternative surgical procedures are often per-
lique reconstructions along axis of pros- formed: total stapedectomy (removal of the
thesis. stapes footplate and insertion of a prosthesis
with graft interposition) (Fig. 2B) and small
fenestra stapedectomy (creation of a fenestra-
tion of the footplate) with or without graft
interposition (Figs. 2C and 2D). Vein, apo-
neurosis, or perichondrial grafts are used in the
former surgical techniques to close the footplate
opening; in the latter, the calibrated fenestration
is directly sealed by the prosthesis. Several types
of stapedial prostheses are available; we used
polytetrafluoroethylene prostheses.

388 AJR:174, February 2000

Helical CT After Stapes Surgery

Downloaded from www.ajronline.org by 50.116.19.84 on 03/11/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved Imaging Technique contiguous scans are usually needed in each correct position on conventional CT scans, but
Helical CT was performed using a Twin plane to image the prosthesis completely. oblique multiplanar reconstructions accurately
Moreover, despite the use of high-resolution show the abnormal location of the prosthesis
Flash system (Elscint, Haifa, Israel) with the slices, the lateral or medial ends are often not (Fig. 5). A separation of the prosthesis ring from
following parameters: single axial helical acqui- precisely seen. Multiplanar reconstructions the long process of the incus is usually associ-
sition (with caudal angulation of the scan plane provided by helical CT acquisition greatly im- ated with a displacement of the tip of the pros-
20° below the orbitomeatal plane to prevent di- prove imaging accuracy by showing the full thesis, resulting in a complete dislocation.
rect lens irradiation); 120 kVp; 440 mAs; pitch: length of the prosthesis on single axial or coro- Sometimes the prosthesis may be displaced far
0.5; slice thickness: 0.6 mm; increment: 0.3 nal reformatted images (Fig. 4). Nevertheless, from the oval window in the posterior or the in-
mm; scan length: 25 mm; acquisition duration: the resolution of reformatted images remains ferior recesses of the tympanic cavity (Fig. 6).
50 sec. A 150-mm acquisition field of view was insufficient to determine the type of surgical
used with a 512 × 512 matrix and a spatial re- procedure (i.e., total or small fenestra stape- Fixation of the Prosthesis by
construction algorithm. Multiplanar reconstruc- dectomy) that has been performed. Postoperative Fibrosis
tions were then performed in oblique axial and
coronal planes along the axis of the prosthesis Prosthesis Displacement Fixation of the prosthesis can be caused
(Fig. 3). Reformatted images of both ears, re- by the development of postoperative fibrous
producing a conventional examination in axial Prosthesis displacement is the most common adhesions to the prosthesis or to the ossicles
and coronal planes, were also obtained. cause of conductive hearing loss recurrence or or covering the fenestra. The fibrous scar
persistence after stapes surgery [1, 6, 7]. The usually appears as a soft-tissue mass around
Prosthesis in Correct Position dislocation of the prosthesis from the stapes the tip of the prosthesis (Fig. 7). Fibrous
The prosthesis in correct position has a me- footplate is in some cases limited to an inframil- tracts between the caudal part of the prosthe-
limetric gap between the footplate plane and the sis and the walls of the tympanic cavity may
dial, posterior, and cranial oblique orientation. tip of the prosthesis; in such cases, the medial also be observed.
In conventional axial and coronal CT, three end of the prosthesis may appear to be in the

A B

Fig. 4.—35-year-old woman with correctly posi- C
tioned polytetrafluoroethylene prosthesis. 389
A, Conventional axial CT scan at level of oval win-
dow shows only tip of prosthesis (arrowhead ). It
is impossible to know whether prosthesis is in
contact with stapes footplate or slightly sepa-
rated from it.
B and C, Oblique (B) axial and coronal (C) multi-
planar reconstructions show entire prosthesis
(arrowhead). Device is correctly inserted on long
process of incus (arrow); no gap is seen be-
tween footplate plane and tip of prosthesis.

AJR:174, February 2000

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AB

Fig. 5.—67-year-old woman with progressive conductive hearing loss occurring 4 years after stapedectomy for stapediovestibular otosclerosis.
A, Conventional axial CT scan shows tip of prosthesis (arrowhead ) apparently in contact with stapes footplate.
B, Oblique axial reconstruction shows anterior displacement of prosthesis. Gap (arrowhead ) between tip of prosthesis (arrow ) and footplate is clearly
visible.

AB

Fig. 6.—59-year-old woman with sudden conduc-
tive hearing loss recurrence after head trauma.
A, Conventional axial CT scan shows prosthesis in
incorrect position; linear dense structure (arrow )
oriented in sagittal plane is seen in front of sinus
tympani recess.
B and C, Oblique axial (B) and sagittal (C) recon-
structions show complete luxation of prosthesis
from long process of incus and from stapes foot-
plate. Prosthesis (arrow ) is located in posterior
part of tympanic cavity.

C
390 AJR:174, February 2000

Obliterative Otosclerosis with Fig. H7.e—li4c3a-yleCar-ToldAfmtaenr SprteasepnetisngSuwritghery
Prosthesis in Correct Position
conductive hearing loss caused by postoper-
Proliferation of the otosclerotic focus may ative intratympanic fibrosis 18 months after
cause the impairment of a correctly located stapedectomy. Prosthesis is correctly in-
prosthesis. The proliferative focus presents serted. Oval window recess is filled by soft-
as a slightly hyperdense calcified space-oc- tissue mass (arrow ) around medial end of
cupying mass in the oval window niche. This prosthesis, causing hearing impairment.
mass surrounds the medial end of the pros-
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plane of the footplate (Fig. 8). The location
of the prosthesis in the hyperdense mass may
be difficult to detect on conventional CT im-
ages because of the oblique orientation of the
oval fossa and the volume-averaging artifacts
of the facial canal located just above the oval
window. Oblique axial multiplanar recon-
structions provide images that are exactly in
the plane of the oval window, improving the
conspicuity of the prosthesis.

Fig. 8.—66-year-old woman with progressive con-
ductive hearing loss 11 years after stapedectomy
and prosthesis placement performed because of
obliterative otosclerosis.
A and B, Oblique axial (A) and coronal (B) recon-
structions show correct location of prosthesis
(curved arrow ). Oval window recess is filled by
proliferative otosclerotic focus (straight arrow )
that surrounds medial end of prosthesis.

A B

A B

Fig. 9.—60-year-old man with persistent conductive hearing loss 6 months after stapes surgery. 391
A, Oblique axial reconstruction shows luxation of prosthesis (straight arrow ) posterior to handle of malleus (curved arrow ).
B, Conventional axial CT scan shows incudomalleal dislocation with enlargement of articular space (arrow ).

AJR:174, February 2000

WilliamFsige. t10a.—l.32-year-old woman with severe vertigo caused by postop-

erative granuloma with resulting displacement of prosthesis. Granu-
loma presents as soft-tissue mass (large arrow ) in front of posterior
part of oval window. Prosthesis tip (small arrow ) is displaced for-
ward by granuloma.

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Fig. 11.—35-year-old woman with sensorineural hearing loss and vertigo caused by intravestibular protrusion of prosthesis 10 days after stapedectomy.
A and B, Oblique axial (A) and coronal (B) reconstructions show protrusion of prosthesis shaft (arrow) in vestibule.

Other Causes of Recurrent Conductive are related to a perilymph leak or to the exten- References
Hearing Loss sion of the granuloma into the labyrinth. CT 1. Shea JJ. Forty years of stapes surgery. Am J Otol
shows a nonspecific soft-tissue mass in the
Other conditions can lead to a conductive oval window recess (Fig. 10). However, the 1998;19:52–55
hearing loss. For instance, a postoperative mal- extension of the granuloma within the vesti- 2. Chakeres DW, Mattox DE. Computed tomographic
leoincudal dislocation [8] appears on axial CT bule cannot be detected on CT because the
scans as an enlargement of the incudomalleal granuloma and the labyrinthic fluid have the evaluation of nonmetallic middle-ear prostheses. In-
articular space, possibly associated with malpo- same density. vest Radiol 1985;20:596–600
sition of the ossicles (Fig. 9). In these cases, the 3. Swartz JD, Lansman AK, Berger AS, et al. Stapes
role of reformatted CT images is to evaluate the Intravestibular Protrusion of the prosthesis: evaluation with CT. Radiology 1986;158:
status of the prosthesis. Osteonecrosis of the Prosthesis 179–182
long process of the incus has been reported as a 4. Kösling S, Woldag K, Meister EF, Reschke I, Hey-
frequent postoperative complication of stapes An intravestibular protrusion of the prosthesis wang-Köbrunner SH. Value of computed tomogra-
surgery [6, 7]. However, such a complication may be observed immediately after the surgical phy in patients with persistent vertigo after stapes
was not observed in our study. procedure but may also have a delayed appear- surgery. Invest Radiol 1995;30:712–715
ance. The protrusion is usually indicated by ver- 5. Yanagisawa E, Lee KJ. Noninfectious diseases of the
Postoperative Granuloma tigo or sensorineural hearing loss. One millimeter ear: otosclerosis. In: Lee KJ, ed. Essential otolaryn-
Labyrinthic symptoms (vertigo, senso- is the generally accepted limit for normal vestibu- gology: head and neck surgery, New York: Elsevier,
lar penetration. Multiplanar reconstructions show 1991:624–625
rineural hearing loss, tinnitus) may indicate the abnormal protrusion of the shaft of the pros- 6. Derlacki EL. Revision stapes surgery: problems with
the development of a postoperative reparative thesis within the vestibular cavity (Fig. 11). some solutions. Laryngoscope 1985;95:1047–1053
granuloma in the oval fossa. The symptoms 7. Hammerschlag PE, Fishman A, Scheer AA. A re-
view of 308 cases of revision stapedectomy. Laryn-
goscope 1998;108:1794–1800
8. Swartz JD, Harnsberger HR, Mukherji SK. The tem-
poral bone. Radiol Clin North Am 1998;36:819–853

392 AJR:174, February 2000

Downloaded from www.ajronline.org by 50.116.19.84 on 03/11/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved This article has been cited by:

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99, 92-94. [CrossRef]

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Findings in Patients with Otosclerosis with Failed Stapes Surgery. American Journal of Neuroradiology 35, 1195-1201. [CrossRef]

3. A. Stasolla, G. Magliulo, A. Cortese, A. Roncacci, M. Marini. 2011. Preoperative imaging assessment of chronic otitis media:
what does the otologist need to know?. La radiologia medica 116, 114-124. [CrossRef]

4. Joel D. Swartz, Mari HagiwaraInflammatory Diseases of the Temporal Bone 1183-1229. [CrossRef]

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7. F. Cyna-Gorse, M. Rodallec, D. Bouccara. 2010. Imaging dell’orecchio medio normale e patologico. EMC - Otorinolaringoiatria
9, 1-21. [CrossRef]

8. I. Granier, B. Escude, V. Poirrier, D. Hoa, A. Bonafe. 2009. Pruebas de imagen en la otospongiosis. EMC - Otorrinolaringología
38, 1-13. [CrossRef]

9. F. Cyna-Gorse, M. Rodallec, D. Bouccara. 2009. Pruebas de imagen del oído medio normal y patológico. EMC -
Otorrinolaringología 38, 1-21. [CrossRef]

10. F. Cyna-Gorse, M. Rodallec, D. Bouccara. 2009. Imagerie de l'oreille moyenne normale et pathologique. EMC - Oto-rhino-
laryngologie 4, 1-21. [CrossRef]

11. I. Granier, B. Escude, V. Poirrier, D. Hoa, A. Bonafe. 2009. Imagerie de l'otospongiose. EMC - Oto-rhino-laryngologie 4, 1-12.
[CrossRef]

12. I. Granier, B. Escude, V. Poirrier, D. Hoa, A. Bonafe. 2009. Diagnostica per immagini dell’otospongiosi. EMC -
Otorinolaringoiatria 8, 1-13. [CrossRef]

13. C. Röösli, A. Hoffmann, T. Treumann, T.E. Linder. 2008. Stellenwert der CT-Diagnostik vor Revisions-Stapedotomien. HNO
56, 895-900. [CrossRef]

14. Frank M. Warren, Sterling Riggs, Richard H. Wiggins. 2008. Computed Tomographic Imaging of Stapes Implants. Otology &
Neurotology 29, 586-592. [CrossRef]

15. A. El Kohen, C.-B. Teszler, M.-T. Williams, D. Ayache. 2007. Déhiscence du  canal semi-circulaire antérieur mimant
une otospongiose: intérêt de l'imagerie. Annales d'Otolaryngologie et de Chirurgie Cervico-faciale 124, 330-332. [CrossRef]

16. D. Ayache, S. Schmerber, J.P. Lavieille, G. Roger, B. Gratacap. 2006. Cholestéatome de l’oreille moyenne. Annales d'Otolaryngologie
et de Chirurgie Cervico-faciale 123, 120-137. [CrossRef]

17. O. Naggara, M.T. Williams, D. Ayache, F. Heran, J.D. Piekarski. 2005. Imagerie des échecs et complications post-opératoires de
la chirurgie de l’otospongiose. Journal de Radiologie 86, 1749-1761. [CrossRef]

18. Francis Veillon, Sophie Riehm, Bogdan Emachescu, Danisia Haba, Marie-Noëlle Roedlich, Michel Greget, Jean Tongio. 2001.
Imaging of the windows of the temporal bone. Seminars in Ultrasound, CT and MRI 22, 271-280. [CrossRef]