Full text of DOI:10.1097/00005537-200203000-00032

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
Reconstruction of Mastoid Cavity With
Hydroxyapatite Cement and Postauricular
Flap
Akhtar Hussain, FRCS; Bhasker Ram, FRCS; Omar J. Hilmi, FRCS
INTRODUCTION
tion using autogenous bone may leave sharp edges of the
newly constructed ear canal wall, facilitating crust forma-
tion and infection in the ear canal. In addition, the bone
may undergo resorption over time with recurrent cavity
formation.
The care of the mastoidectomy cavity is not prob-
lem free. The difficulties vary from minor, infrequent
debridement to chronic, recurrent, and sometimes per-
sistent purulent otorrhoea requiring frequent aural toi-
let and topical treatment.1 Other problems include diz-
ziness associated with cold caloric testing response,
frequent cavity infections with swimming, and difficulty
with fitting hearing aids. It is generally accepted that
an adequate meatoplasty is necessary to minimize prob-
lems with the open mastoid cavity, but some patients
object to the size of the proposed meatus. Middle ear
reconstruction with an open cavity is relatively difficult
because of the absence of the posterior canal wall.
Various techniques are recommended to eliminate
problems associated with open cavity including oblitera-
tion, skin grafting, and reconstruction of posterior canal
wall. Obliteration and reconstruction generally involve
use of soft tissue flaps such as temporalis muscle, tem-
poroparietal fascia, or use of cartilage, bone, and postau-
ricular flap. Pedicled muscle flaps such as the Rambo2 flap
or the flap of Palva and Makinen,3 although readily avail-
able, have the disadvantage of being unable to obliterate
the entire mastoid cavity and later atrophy leading to
recurrent cavity formation.
In recent years, bioactive materials are increasingly
being used in surgical practice for reconstruction, aug-
mentation, or replacement of lost tissue. Although the
search for an ideal bioactive material continues, at
present, hydroxyapatite cement (Howmedica Leibinger
GmbH & Co., Freiburg, Germany) appears to be most
favored and has been shown to be associated with minimal
side effects. Hydroxyapatite cement is a mixture of tetra-
calcium phosphate and dicalcium phosphate anhydrous. It
is inert, biocompatible, rigid, and easy to handle and,
when placed in contact with the bone, has been shown to
be osteoconductive. Long-term studies have shown no ev-
idence of implant resorption, encapsulation, inflamma-
tion. or foreign body reaction.5
We propose reconstruction of mastoid cavity and pos-
terior canal wall during the same procedure with hydroxy-
apatite cement and postauricular flap. The hydroxyapa-
tite cement is used to reconstruct the bony defect in the
mastoid and is covered and isolated from the middle ear
with anteriorly based postauricular periosteal connective
tissue flap. We report a longitudinal cohort of 29 patients
who underwent both primary and secondary mastoid cav-
ity reconstruction using this technique and discuss their
outcomes and complications.
Tympanomastoid obliteration using tragal or conchal
cartilage has been shown to have good integration prop-
erties but the cartilage tend to undergo fibrous degenera-
tion and graft resorption over time.4 Similarly, reconstruc-
Presented at the Summer Meeting of the Scottish Otological Society,
Falkirk, Scotland, June 15, 2001.
MATERIALS AND METHODS
From the Department of Otolaryngology—Head and Neck Surgery,
Grampian University Hospitals, Aberdeen Royal Infirmary, Scotland, U.K.
Editor’s Note: This Manuscript was accepted for publication July 16,
2001.
Send Correspondence to Akhtar Hussain, FRCS, Grampian Univer-
sity Hospitals, Aberdeen Royal Infirmary, Forresterhill, Aberdeen, Scot-
land, U.K. E-mail: akhtarhussain@barclays.net
Indications
Indications include the following: 1) patients undergoing
primary canal wall down mastoidectomy, 2) patients requiring
revision of previous modified or radical mastoidectomy cavity
because of various cavity problems, and 3) patients with mastoid
cavity requiring middle ear reconstruction.
Laryngoscope 112: March 2002
Hussain et al.: Reconstruction of Mastoid Cavity
583

Fig. 1. Completed canal wall down mastoidectomy.
Fig. 3. Post-auricular flap based anteriorly on the concha.
Technique
leave any hydroxyapatite cement exposed in the external audi-
tory canal. A dry surgical field is necessary to prevent particliza-
tion of hydroxyapatite cement. Again, a complete hemostasis of
the flap is achieved with bipolar diathermy.
All procedures were performed with the patient under gen-
eral anesthesia by means of postauricular incision. The incision is
C-shaped and starts at the level of helix above, proceeds down-
ward to the mastoid tip. The incision is placed within the hairline
or just in front of it to allow an adequate amount of soft tissue for
fashioning the postauricular flap. The incision is deepened down
to the periosteum, and a subperiosteal flap is elevated forward to
the level of posterior border of the bony canal in primary mas-
toidectomy. With revision cases, the subperiosteal flap is elevated
up to the posterior margin of the cavity and is carried forward
through the postauricular connective tissue. A complete mastoid-
ectomy is carried out in the standard fashion. Every effort is
made to exenterate all diseased bone and soft tissue (Fig. 1).
Complete hemostasis within the cavity and middle ear is
achieved using bipolar diathermy and topical 1:1000 adrenaline.
Any middle ear reconstruction is completed at this stage, and the
cavity is packed temporarily with cotton-wool balls soaked in
1:1000 adrenaline.
A 10-g amount of a commercially available powdered form of
hydroxyapatite cement is mixed with appropriate amount of ster-
ile water according to manufacturer’s recommendation. This con-
verts the cement into an easily moldable putty (Fig. 3). The putty
is prepared before the flap is harvested; this allows enough time
for the cement to set to some degree without becoming rigid. The
postauricular flap is folded on itself, and the posterior end of the
flap is placed as either an underlay or an onlay in the posterior
part of the middle ear. A thin layer of compressed Gelfoam (Spon-
gaston Special, Johnson & Johnston Medical Ltd., Skipton, UK) is
placed on the posterior surface of the flap, down to the level of
facial recess (Fig. 4). This prevents the hydroxyapatite cement
from running into the middle ear space. The cavity is filled
gradually with the hydroxyapatite cement until it reaches the
level of surrounding bony cortex (Fig. 5). The postauricular inci-
sion is closed in two layers in the standard fashion.
The postauricular soft tissue is injected with saline, and a
thin soft tissue and periosteal flap is elevated based anteriorly on
the concha (Fig. 2). This part of the procedure requires extreme
care to prevent puncture holes and devascularization. The re-
quired flap must be thin and of adequate dimension to be able to
be folded on itself and to be able to cover the hydroxyapatite
cement and any tympanic membrane defect. It is essential not to
The external auditory canal is packed with appropriately
sized Merocel sponge (Xomed, Jacksonville, FL), which is ex-
panded with antibiotic eardrops. A light postauricular mastoid
pressure bandage is applied for 24 hours. The patient is advised
to use topical antibiotic eardrops to keep the external auditory
canal sponge moist and expanded until first review at 4 to 5
Fig. 2. Moldable hydroxyapatite cement putty.
Fig 4. Piece of compressed Gelfoam posterior to the flap.
Hussain et al.: Reconstruction of Mastoid Cavity
Laryngoscope 112: March 2002
584

ment and postauricular flap has been successful in our
hands with minimal problems even though we do not have a
control group. The hydroxyapatite cement is a bioactive, still
inert material that is easy to work with and is moldable to
suit any size or shape of the mastoid bony defect. Some
otologists have concern regarding the detection of recurrent
disease under the reconstructed cavity. However, Yung1 has
shown, both in his cadaveric temporal bone study and in his
series of 31 patients who underwent mastoid obliteration
with hydroxyapatite granules, that computed tomography
scan can be used to detect recurrence of cholesteatoma or
epithelial cyst formation. Eight of our patients underwent
postoperative high-resolution computed tomography scans
with no evidence of residual or recurrent cholesteatoma.6
In our series of 29 patients, there was no clinical
evidence of recurrent cholesteatoma or cement resorption
during the mean follow-up period of 21.6 months. The
technique has been successful in both primary and sec-
ondary reconstruction.
Fig. 5. Cavity filled to the cortex with hydroxyapatite cement.
weeks after surgery. Oral antibiotics are prescribed for the first
week after surgery. On review, the sponge is removed and the
external auditory canal is filled with an antibiotic ointment that
is removed during the next follow-up at 8 weeks. Thereafter,
patients are seen at 3-month intervals.
We do not recommend reconstruction of ossicular
chain simultaneously because the bulk of the flap inter-
feres with proper placement and retention of the prosthe-
sis. Secondary ossicular chain reconstruction would allow
atrophy of the postauricular flap over time and also give
an opportunity to detect any recurrence of cholesteatoma.
RESULTS
Between May 1995 and May 2000, 29 patients under-
went mastoid cavity reconstruction with hydroxyapatite ce-
ment and postauricular flap. All patients had either an open
cavity mastoidectomy or a canal wall down mastoidectomy
There were 16 male and 13 female patients. Ages ranged
between 14 and 72 years (mean age, 41.6 y). Three of the 29
patients underwent primary tympanomastoid reconstruc-
tion. In addition, three patients underwent ossicular chain
reconstruction at the same time. Follow-up ranged from 6 to
48 months (mean period, 21.6 mo). Complications were in-
frequent; two patients developed localized infection, which
settled with appropriate topical treatment. One infection
resulted from exposure of the hydroxyapatite cement, which
required regular local treatment and eventually settled with
re-epithelialization. One patient developed partial loss of the
postauricular flap and required revision surgery.
CONCLUSION
Mastoid cavity reconstruction with hydroxyapatite ce-
ment and the postauricular flap is a technically simple, effi-
cient technique that has been successful in elimination of an
open cavity, circumventing associated problems and thereby
achieving a dry, stable ear with minimal and acceptable
complications. Reconstruction of the cavity also facilitates
reconstruction of the ossicular chain, albeit as a secondary
procedure. It also facilitates hearing aid placement.
BIBLIOGRAPHY
1. Yung MW. The use of hydroxyapatite granules in mastoid
obliteration. Clin Otolaryngol 1996;21:408–484.
2. Rambo JHT. A new obliteration to restore conductive deaf-
ness of chronic suppurative otitis. Arch Otolaryngol 1957;
66:525–532.
One patient developed bony canal stenosis. The ste-
nosis was soft tissue, because of exuberant localized gran-
ulation tissue, which settled with local treatment, and a
dry ear was achieved in all the cases. During the follow-up
period, no recurrent cholesteatoma was seen.
3. Palva T, Makinen J. The meatally based musculoperiosteal
flap in cavity obliteration. Arch Otolaryngol 1979;105:
377–380.
4. Steinbach E, Pusalkar H. Long-term histological fate of car-
tilage in ossicular reconstruction. J Laryngol Otol 1981;95:
1031–1039.
5. Jahn AF. Experimental applications of porous (coralline) hy-
droxyapatite in middle and mastoid obliteration. Laryngo-
scope 1992;102:289–299.
6. Wake M. Robinson JM, Witcombe JB, et al. Detection of
recurrent cholesteatoma by computerised tomography af-
ter closed cavity mastoid. Surg J Laryngol Otol 1992;106:
393–395.
DISCUSSION
Various techniques are recommended for reconstruc-
tion or obliteration of the mastoid cavity. The ideal technique
should be simple and effective and have minimal complica-
tions. Mastoid cavity reconstruction with hydroxyapatite ce-
Laryngoscope 112: March 2002
Hussain et al.: Reconstruction of Mastoid Cavity
585