Clinical and Experimental Otorhinolaryngology Vol. 5, No. 1: 23-27, March 2012 http://dx.doi.org/10.3342/ceo.2012.5.1.

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Original Article

Mastoid Obliteration with Silicone Blocks after

Canal Wall Down Mastoidectomy
Sung Woo Cho, MDYong-Bum Cho, MDHyong-Ho Cho, MD

Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Medical School, Gwangju, Korea

Objectives. To evaluate the usefulness of silicone blocks as graft material for mastoid cavity obliteration in the prevention
of problematic mastoid cavities after canal wall down mastoidectomies.
Methods. Retrospective evaluation of 20 patients who underwent mastoid obliteration with silicone blocks between 2002
and 2009 at the Chonnam National University Hospital. The cases consisted of 17 patients with chronic otitis media
with cholesteatoma and 3 patients with adhesive otitis media. The postoperative follow-up period was an average 49
months (range, 6 to 90 months). The surgical technique used at our institution composed four major steps: First, the
canal wall down mastoidectomy was performed and the middle ear procedure was completed. The silicone blocks
were used to fill up the mastoidectomized cavity. Then, a cortical bone pate was used to cover the surface of the sili-
cone blocks. Finally, temporalis fascia and a split musculoperiosteal flap were used to surround the bone pate for re-
inforcement of the reconstructed canal wall. We examined postoperative success rate and hearing outcomes.
Results. In 19 cases (95%), the reconstructed canal wall maintained a cylindrical shape and the ear drum healed without
perforation. In only 1 case (5%), the reconstructed canal wall was destroyed with ear drum perforation. The mean
improvement in air-bone gap was about 12 dB (P<0.05), and the mean improvement in air-conduction was about 16
dB (P<0.05).
Conclusion. We suggest that silicone blocks could be valuable resources as graft materials for mastoid obliteration after ca-
nal wall down mastoidectomies.
Key Words. Cholesteatoma, Silicones, Mastoid, Reconstructive surgical procedures

INTRODUCTION mastoidectomy include cavity problems, such as continuous ear

drainage, accumulation of keratin debris, frequent vertigo attacks
A canal wall down tympanomastoidectomy is a very effective following temperature or pressure changes, and difficulty in fit-
technique for eradication of advanced chronic otitis media or ting a hearing aid (1, 2). In addition, the final hearing gained af-
cholesteatomas. The advantages of canal wall down mastoidec- ter staged ossiculoplasties in patients who have undergone canal
tomy include excellent exposure for disease eradication and wall down mastoidectomies is usually 5-10 dB worse than pa-
postoperative monitoring, and low rates of residual and recur- tients who underwent canal wall up tympanomastoidectomy
rent disease. However, the disadvantages of canal wall down due to ineffective sound transmission (3, 4). Thus, to overcome
cavity problems, many reports about the mastoid obliteration
Received May 25, 2011 technique have been introduced. Materials used to fill the cavity
Revision July 26, 2011 include several kinds of muscle flap (5), cortical bone pate (6, 7),
Accepted August 2, 2011
allogenous/autogenous bone chips, cartilage (7, 8), and hydroxy-
Corresponding author: Hyong-Ho Cho, MD
Department of Otolaryngology and Head and Neck Surgery, Chonnam apatite (9). However, all of the techniques have advantages and
National University Medical School, 671 Jebong-ro, Dong-gu, Gwangju disadvantages. Herein, we introduce silicone blocks for mastoid
501-757, Korea
Tel: +82-62-220-6772, Fax: +82-62-228-7743
obliteration materials. Silicone blocks are flexible enough to han-
E-mail: victocho@hanmail.net dle and to fit into cavities of variable size, and rigid enough to
Copyright 2012 by Korean Society of Otorhinolaryngology-Head and Neck Surgery.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0)
which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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24 Clinical and Experimental Otorhinolaryngology Vol. 5, No. 1: 23-27, March 2012

prevent collapse in the mastoid. Also, silicone blocks are much were used to obliterate the mastoid cavity in the perilabyrin-
cheaper than other alloplastic materials. thine and retrofacial areas and form a smooth contour lateral to
the facial ridge (Figs. 2C, 3C). Group A only used piecemeal sili-
cone blocks (Fig. 4A), while group B used large silicone blocks
MATERIALS AND METHODS and supplied the deficiency with piecemeal silicone blocks (Fig.
4B). The blocks were fixed using fibrin-based adhesive (Green-
Patients
A retrospective review of patient records was performed on a Stapes
Piecemeal
consecutive series of 20 patients who underwent canal wall down Ear drum conchal
cartilage
tympanomastoidectomies and mastoid obliteration with silicone Facial nerve

block for treatment of chronic otitis media with cholesteatoma

and adhesive otitis media over a 7-year period (2002-2009).
This study was approved by institutional review board (IRB) of A B
our hospital.
Meatal flap
Silicone
block
Silicone preparation Bone pate &
fibrin glue

We cut the silicone (Hansbiomed Co., Daejeon, Korea) (Fig. 1) Silicone block

into small pieces ranging from 2-4 mm in size (group A) and 15- Temporalis
muscle fascia
20 mm (group B), and henceforth referred to as silicone blocks. Facial nerve
C D

Surgical technique Fig. 2. Schematic figures of operating technique. (A) A canal wall
First, we performed a conventional post-auricular skin incision down mastoidectomy is performed for removing of diseases. (B)
and elevated the anterior-based musculoperiosteal flap. Then, we The epitympanic cavity is obliterated with piecemeal cartilage. (C)
harvested the temporalis fascia and elevated the posterior me- Mastoid cavity is obliterated with silicone blocks. (D) Coronal view.
Silicone blocks are covered with bone pate and temporalis muscle
atal skin flap. Healthy cortical bone pate was collected using a
fascia.
specially designed suction line, including a bone dust filter. Ca-
nal wall down mastoidectomy was performed and we removed
all pathologic lesions within the mastoid and middle ear cavities
(Figs. 2A, 3A). Cartilage was harvested from the cymba portion
of the concha cartilage, and cut into small pieces ranging from 
1-3 mm in size. The obtained piecemeal cartilage was usually just
sufficient to allow complete obliteration of the epitympanic space
to re-create the annulus superiorly to the same lateral level as
the facial ridge below (Figs. 2B, 3B). It is at this point that the
new technique differs from other techniques. Silicone blocks
A B




C D

Fig. 3. Surgical procedures for mastoid obliteration with silicone

blocks and bone pate. (A) After elevation of the anterior-based flap,
a canal wall down mastoidectomy is performed. (B) The epitympan-
ic cavity is obliterated with piecemeal cartilage. (C) Silicone blocks
Fig. 1. Silicone (Hansbiomed Co., Daejeon, Korea) is soft enough to are used to fill the mastoid cavity. (D) Silicone blocks are fixed using
be cut by scarpel and easy to be designed, but solid enough to ex- fibrin glue and covered with bone pate. , piecemeal conchal carti-
ist in the mastoid lifelong. lage; , silicone block; , bone pate.
 Cho SW et al.: Mastoid Obliteration with Silicone Blocks 25

 



A B A B

Fig. 4. Group A, mastoid obliteration with piecemeal silicone blocks

and filling with bone pate. Group B, mastoid obliteration with large
silicone block and supplying the deficiency with piecemeal silicone
blocks and bone pate. Dotted line, mastoid cavity; , piecemeal sili-
cone blocks; , large silicone block.

Table 1. Demographic data for both groups

Variables Group A (n=15) Group B (n=5)
Mean age (yr) 37 48
C
Gender (male:female) 8:7 2:3
Cause of operation Fig. 5. Postoperative findings after mastoid obliteration (7 months af-
COM with cholesteatoma 13 4 ter surgery). (A) Photograph of drum and external auditory canal.
Adhesive OM 2 1 Reconstructed posterior wall is well maintained. (B, C) Axial and
Mean dry-up period (day) 45.4 25.4 coronal temporal bone CT scan. The mastoid cavity is well obliterat-
Complication None Recurred otorrhea ed by the silicone blocks (thick arrow) and bone pate (thin arrow).
(1 case)
COM, chronic otitis media; OM, otitis media. low-up ranged from 6 to 90 months (average, 49 months). Fif-
teen patients used piecemeal silicone blocks (group A) and five
plast; Green-Cross, Seoul, Korea). The silicone blocks were then patients used large silicone blocks (group B) (Table 1). All pa-
covered with the previously harvested cortical bone pate and tients in group A had dry ears with good canal contour at the
temporalis fascia was used to enclose the bone pate (Figs. 2D, time of chart review (Fig. 5). In group B, one patient with chron-
3D). The anterior-based musculoperiosteal flap was split into a ic otitis media with cholesteatoma was considered a failure be-
muscle and a periosteal layer. We then placed the periosteal lay- cause of otorrhea and ear drum perforation with a destructed
er between the fascia and bone pate for strengthening the re- posterior ear canal 37 months later after operation. During the
constructed external auritory canal. The postauricular wound revision operation, the silicone blocks and granulation tissue
was closed in the standard fashion. were removed. A revision canal wall down mastoidectomy and
tympanoplasty type III was performed; postoperatively the ear
Audiologic evaluation drum was dry and healthy. Thus, the method used in group B
The audiometric evaluation included pre- and postoperative air- give rise to more complications than group A. However, statisti-
bone gap (ABG), air-conduction thresholds (AC) and bone-con- cal analysis was not performed because the number of group B
duction thresholds (BC). The hearing threshold (dB) was calcu- patient was so small. The mean dry up period was 40.4 days. We
lated as the mean value of the threshold for 500, 1,000, 2,000, performed postoperative pure tone audiograms in 14 patients.
and 4,000 Hz. Paired-samples t-test was used for comparison of With the exception of 1 patient with disease recurrence and 2
the pre- and postoperative air conduction hearing thresholds patients with planned 2nd look operations, the postoperative
and ABGs. A P<0.05 was accepted as statistically significant. air-bone gap decreased to < 25 dB. The mean improvement in
air-bone gap was about 12 dB (P<0.05), and the mean improve-
ment in air-conduction was about 16 dB (P<0.05) (Table 2).
RESULTS

Twenty patients underwent mastoid obliteration using silicone DISCUSSION

blocks and cortical bone pate between 2002 and 2009. Ten pa-
tients were male and ten were female. The average age of the The management of chronic ear disease occasionally requires
patients was 39.8 years (range, 9 to 62 years). The length of fol- canal wall down mastoidectomy for appropriate surgical man-
26 Clinical and Experimental Otorhinolaryngology Vol. 5, No. 1: 23-27, March 2012

Table 2. Clinical and audiologic features of patients who underwent In our study, 19 patients had a dry canal and good contour on
mastoid obliteration with silicone blocks their regular return visit. One patient in group B had otorrhea
No. Preop. PTA Postop. PTA Dry-up Silicone Preop. Postop. Recur- and ear drum rupture with a destructed posterior ear canal 37
(BC/AC) (BC/AC) period type ABG ABG rence months after the operation. We considered the reason for failure
(dB) (dB) (day) (dB) (dB) was infection of the bone pate. We performed a revision proce-
1 23/48 9/28 44 A 25 19 No dure and removed the silicone blocks. Currently, the ear is dry
2 29/40 14/25 23 A 11 11 No and clean. As a preliminary clinical report, our results indicate
3 24/38 30/37 27 A 14 7 No
that silicone blocks with a bone pate and musculoperiosteal flap
4 20/65 15/30 63 A 45 15 No
are likely to be useful for mastoid obliteration. As with any graft
5 30/70 25/50 21 A 40 25 No
material for mastoid obliteration, long-term follow-up and addi-
6 13/32 10/20 22 A 19 10 No
7 23/46 27/40 180 A 23 13 No tional case review will be necessary to evaluate the stability of
8 18/40 17/26 40 A 22 9 No the material over a prolonged period of time. A prospective
9* 15/48 15/50 33 A 33 35 No case-control study is needed.
10* 10/55 10/75 62 A 45 65 No Based on these results, piecemeal silicone blocks with a bone
11 43/75 48/61 45 B 32 13 No pate and musculoperiosteal flap appears to be very effective for
12 20/60 20/30 14 B 40 10 No mastoid obliteration. The coverage of the bone pate by a split
13 10/25 10/15 26 B 15 5 No musculoperiosteal flap appears to prevent infection of the bone
14 13/53 34/80 21 B 40 46 Yes pate and exposure of the silicone blocks. We suggest that silicone
15 28/48 Cant check 45 A 20 . No
blocks could be one of valuable resources as graft materials for
16 20/46 Cant check 28 A 26 . No
mastoid obliteration after canal wall down mastoidectomies.
17 10/35 Cant check 24 A 25 . No
18 45/65 Cant check 21 B 20 . No
19 55/82 Cant check 31 A 27 . No
20 31/69 Cant check 38 A 38 . No CONFLICT OF INTEREST
PTA, pure tone audiogram; Preop., preoperative; Postop., postoperative;
ABG, air-bone gap; BC, bone conduction; AC, air conduction. No potential conflict of interest relevant to this article was re-
*Planned 2nd look operation (No. 9, 10). ported.

agement. However, there are some complications with canal wall

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