Full text of DOI:10.1097/00005537-200209000-00032

The Laryngoscope
Lippincott Williams & Wilkins, Inc., Philadelphia
© 2002 The American Laryngological,
Rhinological and Otological Society, Inc.
How I Do It
A Targeted Problem and Its Solution
Temporalis Fascia Assisted Ossicular
Arthroplasty for the Dislocated Incus:
Fascial Arthroplastic Ossiculoplasty
Pandharinath S. Mundada, MS; Kalpana S. Dasgupta, MS; Girish B. Tapadiya, MS
INTRODUCTION
fascial ties by Farrior5 in 1969 to secure the position of the
A disruption of the incudostapedial joint or gross
dislocation of the incus occurs most often as a result of
accidental head trauma but may also result occasionally
from surgical injury or temporary disarticulation during
ear surgery for clearing the underlying disease or expos-
ing the facial nerve.
bone graft with the incus and the stapes in cases of loss of
the long process of incus was the forerunner of our con-
cept. Evolving further, a method referred to as “fascial
arthroplastic ossiculoplasty” was used for the reposition-
ing of a dislocated incus with reconstruction of its joint
capsule and supporting accessory ligaments using tempo-
ralis fascia grafts. The fascial grafts used to refurbish the
articular structures initially cover the articular cavity,
splint and support the ossicular assembly, provide nutri-
tion through tissue fluids, prevent bony ankylosis and,
after its healing, ensures a firm and movable union of the
repositioned incus with the malleus and the stapes with
full functional restoration.
The surgical management of a dislocated incus often
presents a challenging technical and biological problem
because its joints are not designed for reunion like other
skeletal joints of the body.1–3 They differ in size, strength,
and movements permissible to them. Bereft of muscular or
soft tissue cushioning for support, these joints depend on
fibrous capsular tissue to maintain joint integrity. The
role of the atmospheric pressure and gravity is crucial
because the incus often gets displaced from its corrected
position in absence of capsuloligamentous support. Hence,
simple repositioning of the dislocated incus is usually
ineffective unless its periarticular (joint capsule) and
intra-articular (articular meniscus) structures are recon-
stituted to prevent recurrence of the dislocation and the
post-traumatic joint stiffness or bony ankylosis.3 Free
transplantation of fascia in “interpositional fascial arthro-
plasty” has proven its usefulness as substitute for articu-
lar ligaments and as an inlay in skeletal joint restorative
surgery.4
PATIENTS AND METHODS
A retrospective study was performed by studying the charts
of 342 patients who had surgery April 1990 and January 2001.
The degree of dislocation varied from simple subluxation of the
incudostapedial joint to a complete dislocation of the incus.
Follow-up ranged between 1 and 11 years. Their hearing results
were also studied.
Subluxation or Separation of Incudostapedial
Joint
In 178 cases of subluxation of the incudostapedial joint, 31
cases were of accidental trauma, 11 were of acoustic trauma, and
8 were of surgical trauma, and in another 128 cases the disartic-
ulation was intentional during chronic ear surgery to protect the
inner ear from manipulatory and vibratory trauma.
Fascial arthroplasty of a displaced incus where tech-
nically possible should be attempted.3 The original use of
Presented in part at the 51st Annual Conference of the Association
of Otolaryngologists of India, Guvahati, India, January 8, 1999.
From the Department of Otolaryngology—Head and Neck Surgery,
Indira Gandhi Government Medical College (P.S.M., K.S.D.) and Mundada
Otolaryngological Clinic (G.B.T.), Nagpur, India.
Editor’s Note: This Manuscript was accepted for publication Febru-
ary 6, 2002.
Send Correspondence to Pandharinath S. Mundada, MS, 6 Central
Avenue, Nagpur-440 018, India. E-mail: mukund@nagpur.dot.net.in or
Baheti50@hotmail.com
Surgical Technique
It became possible to restore the hearing in these cases
simply by repositioning the tip of the long process of the incus on
the head of the stapes after interposing a piece of fascia between
its joint cavity to prevent bony union. However, often after its
replacement the lenticular process springs away laterally and
must be fixed again to the head of the stapes with a fascial scarf
(Fig. 1E). This small piece of fascia covering the articular surface
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Mundada et al.: Fascial Arthroplastic Ossiculoplasty
1699

was sufficient to prevent passive movements including pulling
apart of the surfaces. The fastening of the incus to the stapes is
such that the mobility of the incudostapedial joint is maintained.
In a few cases, because of post-traumatic scarring, repositioning
of the lenticular process of the incus on the head of the stapes
could not be accomplished. In such cases, the bone from the
posterior canal wall was removed to expose the incus and head of
the malleus, the fibrous tissue responsible for malalignment was
resected, the separated incus was replaced in its original position,
and the joint reconstituted (Fig. 1C and D).
Surgical Technique
After the accident, reduction was accomplished as
early as possible because the articular cavity is fresh and
of the same size and, if reduction is delayed, becomes
partly filled by reparative fibrous tissue. An exploratory
tympanotomy was performed, and the bone from the canal
wall was removed to expose the epitympanum, dislocated
incus, and head of the malleus (Fig. 1A). After positioning
a small piece of Silastic sheeting (0.005 inches, Dow Corn-
ing, MI) in the epitympanum to cover the exposed facial
nerve (if any) or the denuded bone, a gelatin sponge bed
was prepared at the recipient site with a piece of fascia
spread over it to cover the medial surface of the articular
cavity of the incudomalleolar joint of the repositioned in-
cus (Fig. 1B). The dislocated incus was placed in its nor-
mal position after interposing a piece of fascia in the gap
between the incudomalleolar and incudostapedial articu-
lations for prevention of bony union and for improving the
joint mobility. In addition, to avoid bony fixation of the
short process of the incus with the fossa incudis, another
piece of fascia was placed under the articular surface of
the short process of the incus covering the bone posterior
to it (Fig. 1C). After an accurate realignment and approx-
imation of the joint surfaces to avoid articular instability,
a new joint capsule was reconstructed by wrapping the
medially placed band of fascia around the incudomalleolar
articulation. Another piece of fascia was positioned on the
lateral surface of the incudomalleolar articulation cover-
ing the ends of the fastened first fascial strip and the other
replaced ossicular fascial ligaments (Fig. 1D). Other ac-
cessory ossicular ligaments (posterior ligament of the in-
cus and the superior incudal ligament) were reconstructed
at their respective sites by placing suitable-sized pieces of
fascia covering the ossicles and walls of the tympanic
cavity and were held in position by several small pieces of
blood-soaked absorbable gelatin sponge. The cut ends or
RESULTS
Hearing results were analyzed after the preoperative
and postoperative air- and bone-conduction thresholds
(International Standards Organization standard) were ob-
tained based on the differences in the mean thresholds for
500, 1000, 2000, and 3000 Hz (Table I). A comparison was
made between the results of the last preoperative and last
postoperative tests. The hearing improvement with al-
most complete closure of the air–bone gap was found in 54
(30.3%) of the ears, within 10 dB in 104 (58.5%) of the
ears, and within 15 dB in 20 (11.2%) of the ears. These
were found to be in conformity with the severity of the
associated tympanic disease varying from mucosal edema
and granulation tissue to limited attic retraction pockets.
Total Dislocation of Incus
We have encountered 164 cases of total dislocation of
the incus. Of these, 18 (including 2 cases of dislocation
with fracture of long process of the incus) cases were
attributable to head injury, 10 cases were from accidental
surgical subluxation, and in 136 cases the incus was elec-
tively removed either for clearance of the scar tissue,
squamous debris, or granulation tissue blocking the an-
trum or for gaining adequate exposure during facial nerve
decompression for idiopathic (Bell’s) or traumatic facial
nerve palsy.
Fig. 1. (A) Total dislocation of the incus (the
malleus and the stapes intact). (B) Prepara-
tion of the recipient bed for the incus. Over a
piece of silastic sheet, a thin, compressed
piece of gelatin sponge was positioned with
a piece of fascia spread over it to cover
medial surface of incudomalleolar joint. (C) A
piece of silastic sheeting to cover the de-
nuded bone or the exposed facial nerve and
two pieces of fascial grafts interposed be-
tween the incudomalleolar and incudosta-
pedial joints. (D) Incus replaced in its ana-
tomical position and the medially placed
fascial strip turned up to cover lateral surface
of the incudomalleolar joint. Another piece of
fascia positioned to cover lateral surface of
the incudomalleolar joint, folded ends of the
first fascial strip, and the superior incudal
ligament. Posterior ligament of the incus re-
placed with a fascial strip. The lenticular pro-
cess of the incus reattached to the head of
the stapes with a fascial scarf. (E) Inset:
Magnified image of the incus–stapes cou-
pling with a fascial scarf. The lenticular pro-
cess of the incus replaced on the fascia-
covered capitulum of the stapes with a
fascial scarf.
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Mundada et al.: Fascial Arthroplastic Ossiculoplasty

the detached tendon of the intratympanic muscles, if any,
were reapproximated and securely moored with a fascial
splint. Similarly, the fracture injury of the long process of
the incus was repaired by reducing the fracture and im-
mobilizing the fragments with a cartilage splint secured
by fascial ties. The chorda tympani nerve was later posi-
tioned over the reposed ossicular assembly supporting it.
These wet fascial strips readily conform to bony surfaces
and cause no rumple at the site of reconstruction and do
not impede transmission of the acoustic vibrations. Even-
tually, these joints are put through the full range of move-
ments with those of the tympanic membrane and with the
reflex actions of the intratympanic muscles reducing the
chances of ankylosis.
Hearing Results
Of the 164 cases (including 2 cases of dislocation with
fracture of the long process of the incus) treated for total
dislocation of the incus, 152 cases (92.7%) had good heal-
ing of the grafted tympanic membrane and 135 (80.3%)
closed the air–bone gap within 10 dB; in 29 cases (17.3%)
hearing improved but a larger postoperative air–bone gap
than 10 dB was left, and in the remaining 12 cases (7.3%)
repeat perforation occurred during the follow-up period
that healed after revision myringoplasty. Table I sums up
the details of the hearing results of the 342 operated ears.
In none of the cases did hearing worsen postoperatively.
These results were satisfactorily commensurate to the
type and extent of the disease encountered. Unlike sub-
luxation of the incudostapedial joint, in total dislocation of
the incus, both incudomalleolar and incudostapedial joints
were reconstructed; hence, complete closure of the air–
bone gap was not feasible. Second-look operations were
not routinely performed as part of a general strategy un-
less the patient had problems with healing or hearing. All
these patients were regularly evaluated, and their hearing
improvement was found to be stable and unchanged.
DISCUSSION
Technique
The problem of interposing a dislocated incus be-
tween the malleus and the stapes is an intriguing one
beset with many difficulties. These include a lack of vas-
cular bed for its survival, maintaining it in anatomical
position in the absence of its capsuloligamentous support,
and avoiding bony ankylosis in the reconstituted incud-
omalleolar and the incudostapedial joints.3
The precept of our surgical procedure has evolved
from the observations of methods of surgical pseudoar-
throsis and the interpositional arthroplasty used in ortho-
pedic surgery in which the fascial grafts are interposed
between the mobilized bony ends of an ankylosed joint and
the fascial strips are used to repair the torn, deficient
parts of the articular capsule.4–6 In fascial arthroplastic
ossiculoplasty, the fascial grafts were systematically ar-
ranged to create the articular structures and the liga-
ments of the replaced ossicle allowing its free movements.
These fascial grafts were found to remain viable, and the
grafts interposed between the joint cavities serve to min-
imize the frictional resistance to movement generated be-
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Mundada et al.: Fascial Arthroplastic Ossiculoplasty
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tween two dry, rough articular areas preventing second-
ary traumatic osteoarthrosis and bony ankylosis.4,6 There
is ample evidence that the synovial membrane can be
reformed from ordinary connective tissue as in cases of
pseudoarthrosis or its regeneration after synovectomy.4,6
An experimental finding demonstrated that these fascial
grafts, when used for ossiculoplasty, achieve blood circu-
lation through longitudinal vascular network within 48
hours and are preserved forever.7 Initially, the surface
cells of the replaced ossicle imbibes its nourishment from
tissue fluids through its temporal fascia covering; finally,
the entire reconstructed ossicular assembly gets covered
with the middle ear mucosa ensuring its blood supply from
the mucosal plexus.7
In our experience, this method of ossiculoplasty has
granted an essential freedom to an otologist. Formerly,
much time was spent attempting to remove granulations
or cholesteatoma from an intact ossicular chain, often
resulting in recurrence of disease or sensorineural hearing
loss from the manipulations. Our technique minimizes
these problems by removing the incus temporarily to weed
out all disease and the degenerated ligaments with the
knowledge that it can be replaced in its original position
with reconstitution of ligamentous support at the conclu-
sion of the operation. Initially, we were hesitant to per-
form standard repositioning of the incus using this
method after facial nerve decompression because of the
close proximity to the exposed nerve. However, this con-
cern has proved baseless because postoperative recovery
of the facial nerve in these cases was good without any
significant difference in hearing acuity.
In few cases, the revision operation for the minor
graft perforation showed the reposed incus in position
with neatly healed incudomalleolar and incudostapedial
joints and a delicate band of connective tissue running
from the head of the malleus and the incus to the tegmen
tympani resembling the superior malleoincudal fold.
Thus, there is evidence that the suspensory ligaments of
the ossicles can be reformed with this method; the au-
tografted ossicles get biologically adopted with satisfac-
tory joint healing and are able to maintain its size and the
shape as this fascial cover prevents further remodeling
and the new bone formation around it. This has been
clinically confirmed in a number of patients in whom the
incus was well visualized through the thin tympanic mem-
brane after a period of 1 year, and it is obvious from the
improved hearing results that it works effectively.
that many transpositions had failed because the ossicle
was pulled off the capitulum or it slipped and got attached
to the bony walls of the tympanum.5,8 Nikolaou et al.9
performed 40 incus transpositions and achieved closure of
the conductive loss to within 20 dB in 74% of the cases.
The mechanical advantages offered by this approach have
helped us to develop a technique that can be used to repair
a wide variety of intricate ossicular defects using autolo-
gous ossicular or cortical bone grafts.
CONCLUSION
The contemporary techniques used for the reposition-
ing of the dislocated incus do not involve the repair of
ossicular joints, ligaments, and the intratympanic mus-
cles. A new microsurgical concept, “fascial arthroplastic
ossiculoplasty,” is presented, which was successfully per-
formed in 342 patients for the repositioning of a dislocated
incus. The fascial strips used to hold the repositioned
incus in its anatomical position and the fascial dividers
that separate the coupling surfaces of the articulating
ossicles help in maintaining firm, mobile articulations of
the repositioned incus with the malleus, fossa incudis, and
head of the stapes. The procedure is simple, and its post-
operative results are more predictable and reproducible.
Acknowledgments
The authors thank K. C. Gadre and K. B. Bhargava,
Emeritus Professors of Otolaryngology, University of
Bombay (Bombay, India); Vikram Marwah, Emeritus Pro-
fessor of Orthopedics, University of Nagpur (Nagpur, In-
dia); and Dr. Anant K. Chaudhary, Consultant Otologist
at Mumbai (India), for their invaluable suggestions.
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