Keywords
platelet-rich plasma - titanium - cholesteatoma
Introduction
The goals of the surgery for cholesteatoma are to eradicate the disease and prevent
its recurrence. Canal wall up (CWU) mastoidectomy preserves the posterior canal wall,
obviating the need for repeated mastoid cavity cleaning and preventing recurrent mastoid
cavity infections. However, the recurrence rate is very high (∼ 36%) in adults and
in children (67%).[1]
In the canal wall down (CWD) mastoidectomy, the posterior meatal wall (PMW) is removed,
providing exposure of the entire attic and middle ear, helping to ensure complete
disease eradication. Hence, the recurrence rate is as low as 2% for this procedure.[2]
[3]
[4] However, CWD mastoidectomy has many drawbacks, such as cavity problems (chronic
otorrhea, granulations, dizziness in cold or hot water, and accumulation of debris
in the exteriorized mastoid cavity, requiring periodic cleaning), social handicaps
(non-esthetic meatoplasty, water restrictions to prevent bowl infections) and/or hearing
problems (major conductive or mixed hearing loss as the ossicular chain reconstruction
is very difficult, as is the insertion of a hearing aid).[5]
[6]
CWD mastoidectomy followed by concomitant reconstruction of the PMW achieves the low
recurrence rate of cholesteatoma after it besides the advantages of CWU mastoidectomy.
This provides a structural support, which plays an important role in the prevention
of the postoperative formation of a retraction pocket and subsequent cholesteatoma
development.[6]
[7]
[8]
The materials used for PMW reconstruction can be classified into two main categories:
autologous grafts (bone, cartilage) and synthetic materials.[9]
These grafts have limited supply,[10] and can be associated with donor-site morbidity and new cavity formation after tissue
retraction.[11] Many of these problems can be avoided with the synthetic materials,[12] which should be available, non-expensive, and biocompatible, and should not be extruded
or resorbed,[13] such as titanium mesh.[12]
Titanium is biocompatible and can osteointegrate with the bone;[14] in addition, titanium mesh is a malleable material, so it can be easily shaped according
to the surgical requirements.[15]
Platelet-rich plasma (PRP) is an autologous product derived from whole blood through
the process of gradient density centrifugation. Autologous PRP has been shown to be
safe and effective in promoting the natural processes of wound healing, soft tissue
reconstruction, bone reconstruction and augmentation.[16]
The aim of this study was to assess the results of PMW reconstruction after CWD mastoidectomy
for cholesteatoma using titanium mesh and PRP mixed with bone pate intraoperatively.
Patients and Methods
This study was conducted from May 2012 to February 2015 on 20 patients who had cholesteatoma;
there were 9 males and 11 females, with ages ranging from 12 to 36 years. These patients
underwent CWD mastoidectomy followed by concomitant reconstruction of the PMW using
titanium mesh and PRP mixed with bone pate in the Otolaryngology Head and Neck Surgery
Department of our institution. All patients had atticoantral chronic suppurative otitis
media (cholesteatoma).
Revision cases, patients with intracranial complications and labyrinthine fistula
were excluded. An informed consent form was signed by every patient included in this
study, and approval was obtained from the institution's Review Board.
All patients were subjected to history-taking, and thorough general and otorhinological
examinations, including a microscopic ear examination. Pure tone audiometry (PTA)
was performed preoperatively and one year postoperatively. The air conduction threshold
for each patient was calculated as the mean of the 0.5, 1, 2, and 4 kHz thresholds.[17] Computed tomography (CT) scans of the temporal bone were performed in all patients
both preoperatively and one year postoperatively.
Surgical Techniques
Under general anesthesia, during anesthesia induction, the PRP was prepared by taking
5 cc of autologous blood from the patient and processing it during the mastoidectomy
using a laboratory centrifuge (Heraeus labofuge 200, Germany) ([Fig. 1]). Then, CWD mastoidectomy was started by postauricular incision, and the postauricular
superiorly based mucoperiosteal flap was created. The large temporalis fascia graft
was then prepared. Canal wall down mastoidectomy with lowering of the facial ridge
was performed, but earlier in this step, a sufficient amount of bone pate was collected
from the healthy bone of the mastoid, the squamous temporal bone, and the zygomatic
root. The PRP was mixed with the obtained bone pate to form a paste.
Fig. 1 Platelet-rich plasma.
Reconstruction of the Posterior Meatal Wall
The titanium mesh used in this study was 0.1 mm thick, with 2 mm pores (Titanium Micromesh,
JEIL medical corporation, Seoul, Korea). Two deep grooves in the bone along the facial
ridge posteriorly and inferiorly and along the anterior–superior wall of the meatus
were drilled with a 2 to 3mm cutting burr. A foil template gave the accurate measurements,
and the curvature of the posterior canal wall was used to get the template of the
PMW. Using the foil template as a model, the prosthetic wall was cut from the titanium
mesh, and a little piece from the mesh like a tail was extended from the prosthetic
wall. The mesh was then folded and placed into the created grooves, and the tail extended
from the mesh was fixed with one titanium screw to the cavity border to allow for
a better fixation of the prosthetic wall. The PRP and bone pate paste was used to
cover the meatal surface of the mesh completely. The titanium mesh supports the layer
of PRP bone pate paste that will become viable bone later on. ([Fig. 2])
Fig. 2 Titanium mesh inserted between the two grooves with fixation of the titanium tail
by titanium screw.
The prepared temporalis fascia graft was used to reconstruct the tympanic membrane
perforation and extended over the newly reconstructed PMW. ([Fig. 3])
Fig. 3 Posterior meatal wall completely reconstructed by titanium mesh and PRP and bone
pate paste, and the tympanic membrane reconstructed by temporalis fascia.
Thereafter, the prepared post-auricular superiorly based mucoperiosteal flap was rotated
into the mastoid cavity, obliterating it and supporting the newly reconstructed PMW.
Then, the tympanomeatal flap was repositioned over the newly reconstructed PMW, and
was secured in its position using Gelfoam (Pfizer, New York, NY, US).
Therefore, the newly reconstructed PMW consisted of the titanium micromesh, the PRP
and bone pate sheet, the temporalis fascia graft and the tympanomeatal flap. Lastly,
the post-auricular incision was closed in layers.
The temporalis fascia graft was applied over the newly reconstructed PMW before repositioning
of the tympanomeatal flap to avoid any possibility of exposure of any part of the
new wall, as the flap is not always kept intact during the elevation.
The dressing and the stitches were removed one week postoperatively. Otoscopic and
otoendoscopic examinations were performed weekly for the first month, then monthly
for 3 months, then every 3 months afterwards ([Fig. 4]). Pure tone audiometry and a CT of the temporal bone were taken one year postoperatively
([Fig. 5]). The postoperative hearing gain was calculated as the preoperative air conduction
threshold minus the postoperative one; the bone conduction was not evaluated, as we
had used the change of air bone gap as a parameter for the evaluation, and all patients
included in the study were having pure conductive hearing loss preoperatively, and
there were no cases in which the bone conduction was changed postoperatively.
Fig. 4 Follow-up of a case operated 12 months before.
Fig. 5 Coronal CT showing the reconstructed PMW after 12 months.
Statistical Analysis
Statistical analysis was conducted using the Statistical Package for the Social Sciences
(SPSS Inc, Chicago, IL, US) statistical software, version 14.0 for Windows. Values
of p < 0.05 were considered statistically significant.
Results
This study included 20 patients who had cholesteatoma; 9 males and 11 females, with
ages ranging from 12 to 36 years (mean 23.1 ± 8.4).
No difficulty was reported during the fashioning and the building of the new PMW by
titanium mesh and PRP and bone pate paste.
During the follow-up of 12 to 36 months (the mean follow-up was 24.3 ± 7.49 months),
the postoperative appearance of the external auditory canal contour was smooth without
hidden pouches, irregularities or stenosis in all cases, and no granulation, foreign
body reaction, extrusion and/or displacement of the titanium mesh (that means that
there was good osteointegration of the titanium mesh) were registered. No facial palsy
or recurrent cholesteatoma was reported. This was evaluated not only by clinical examination,
but also by a CT that was performed in all cases one year postoperatively
Postoperative temporary otorrhea had occurred in 2 ears (10%), and it stopped with
antibiotics (for 7 days) and strict water precautions.
The preoperative air bone gab (ABG) ranged from 20 to 42 dB, with a mean of 28.1 ± 6.3
dB. The postoperative ABG ranged from 22 to 42 dB, with a mean of 29.6 ± 6.1 dB ([Table 1]).
Table 1
Preoperative and postoperative air bone gab (ABG)
|
Air bone gab (ABG)
|
Preoperative
(N = 20)
|
Postoperative
(N = 20)
|
WSR
|
p-value
(Sig)
|
|
Mean ± SD
|
28.1 ± 6.3
|
29.6 ± 6.1
|
-1.250
|
0.211
(NS)
|
|
Median
|
27.5
|
27.5
|
|
Range
|
20–42
|
22–42
|
Abbreviation: SD, standard deviation; Sig, significance; NS, non significant; WSR,
Wilcoxon Signed Ranks test.
Note: Values of p < 0.05 were considered statistically significant.
Discussion
In CWU mastoidectomy, the PMW is preserved avoiding the need for recurrent bowl cleansing
and preventing recurrent bowl infection. But the recurrence rate is high (∼ 36% in
adults and 67% in children).[1] On the other hand, CWD mastoidectomy is an easier operation, requires less operative
time, and calls for less surgical experience than the CWU procedures, with lower recurrence
and residual rate, so it is the most commonly used surgical procedure for the management
of cholesteatoma worldwide.[17]
The surgical techniques used for the management of open mastoid cavity after CWD mastoidectomy
include obliteration (cavity filling), reconstruction (canal wall defect repair) and
ablation (external canal closure). The obliteration technique involves filling the
mastoid cavity with pedicled flaps and/or various materials, such as fat, bone chips
and hydroxyapatites. The ablation or canal closure technique is only recommended in
certain cases, such as a deaf ear with severe otorrhea.[18]
We have used a combination of both PMW reconstructions in addition to mastoid cavity
obliteration. We used the titanium mesh and PRP and bone pate paste in PMW reconstruction
that was tailored and built-up during surgery. Then, we managed to hold the newly
reconstructed PMW from the mastoid surface through mastoid obliteration by a superiorly
based mucoperiosteal flap.
Titanium has been widely used in maxillofacial, otolaryngological and surgical reconstructive
procedures.[19]
[20]
[21] It has been proven to be biocompatible and osteointegrative.[14] Platelet-rich plasma has been shown to be safe and effective in promoting the natural
processes of wound healing, soft tissue reconstruction, and bone reconstruction and
augmentation.[16]
In this procedure, the PMW was reconstructed by titanium mesh and PRP and bone pate
paste, while in the study conducted by Zini et al study, the PMW was reconstructed
by titanium mesh, but the bone pate was mixed with fibrin glue.[15] Platelet-rich plasma differs from fibrin glue, as PRP has a high concentration of
platelets and normal concentration of fibrinogen, whereas autologous fibrin glue can
be created from platelet-poor plasma and consist primarily of fibrinogen (commercial
fibrin glues are created from pooled homologous human donors). The high concentration
of platelets in PRP promotes wound healing, bone growth, and tissue sealing.[16]
Platelets have been shown to stimulate the mitogenic activity of human trabecular
bone cells and to increase the proliferation rate of human osteoblast-like cells and
stromal stem cells, thus contributing to the regeneration of mineralized tissues.
Growth factors released from platelets signal local mesenchymal and epithelial cells
to migrate, divide, and increase the synthesis of collagen and matrix, thus providing
a scaffold that encourages the migration of osteoblasts. Growth factors contained
in PRP also stimulate chemotaxis, metabolism, and proliferation in osteoblasts and
in bone marrow osteoprogenitor cells.[22]
[23]
In a study conducted by Sudhoff et al, the PMW was reconstructed with a composite
cartilage titanium mesh.[24] In this study, the mesh surface must be completely covered with cartilage, so a
large amount of cartilage should be harvested from the concha and fixed to the mesh
by absorbable sutures, which is time-consuming with donor site morbidity, while in
our study the PRP and bone pate paste is easily prepared and less time-consuming.
With regards to the stability, the newly reconstructed PMW by titanium mesh and PRP
and bone pate paste was stable when applied, with no reported extrusion or displacement.
This agrees with Zini et al[15] and Sudhoff et al.[24]
Silicone, proplast, ionomer cement, ceravital and hydroxyl apatite are examples of
synthetic materials that have been used in PMW reconstruction. But silicone leads
to foreign body reaction;[25] the use of proplast leads to dehiscence problems;[26] ionomer cement leads to infection and encephalopathy;[27] and ceravital leads to absorption and lysis.[13]
[28]
In this study, the PRP and bone pate paste proved to be easily prepared and applied
over the titanium mesh. Postoperative infection had occurred only in 2 cases (10%),
which responded well to antibiotics and conservative treatment, and this confirms
the wound healing promotion effect of the PRP.[16]
Sudhoff et al[24] registered the occurrence of granulations in 2 patients, apparently due to incomplete
coverage of the titanium mesh by cartilage. Zini et al[15] reported the development of granulations in one patient. In our study, no granulations
were detected, and this may be explained by the healing promotion effect of the PRP,
which was mixed with the bone pate, allowing for the complete covering of the mesh
surface and encouraging healing and bone formation.
In this study, all patients (100%) showed smooth and apparently normal PMW contours,
which agree with Zini et al[15] and Sudhoff et al.[24]
Regarding the postoperative hearing changes in our study, there were no significant
changes in hearing in which the mean pure tone average air–bone gap had increased
from 28.1 dB to 29.6 dB (in this study, ossiculoplasty was not performed, as the goal
was to reconstruct the posterior meatal wall mainly, then the ossicles could be reconstructed
later on in another set of surgeries), and this agrees with Zini et al[15] and Sudhoff et al.[24]
So, PRP appears to be reliable and safe, as it encourages the bone formation of the
PMW effectively and improves healing with no reported complications for the surgical
reconstruction of the PMW.
Conclusion
Surgical reconstruction of the PMW using PRP with titanium mesh after CWD mastoidectomy
appears to be reliable and devoid of considerable complications, giving a smooth appearance
to the PMW and improving healing. But the follow-up period is relatively short, so
we recommend further studies with longer follow-up periods to evaluate our results.
