DISCUSSION
All patients in this study underwent endoscopic myringoplasty without
canaloplasty. Two cases were treated with sleeve resection of the EAC
skin due to EAC stenosis. In addition to traditional endoscopic
cartilage myringoplasty, an extra patch of perichondrium was used to
enhance the anterior-inferior tympanic membrane if preoperative
evaluation revealed dysfunction of eustachian tube or the graft did not
tightly fit the residual tympanic membrane during operation. At sixth
month follow-up, all the tympanic membranes healed well without
fissure-like perforation or obtuse-angle healing, leading to a 100%
healing rate of tympanic membrane. Although some patients had
hypertrophy and swelling at the site of the extra patch, the symptoms
improved during follow-up.
The audiological evaluation at month six post-operation showed
significant decrease in ABG, compared with preoperative values. All
patients had external auditory meatus healed smoothly and epithelized
well, without bone exposure or granulation. Only a few minor
complications were observed and all of these complications had resolved
by the end of follow-up. These results and observation demonstrate that
it is an effective and safe procedure to add an extra patch anterior to
the graft and enhance the tympanic membrane.
Endoscopic myringoplasty has become popular in recent decades and its
effectiveness and safety have been ascertained by multiple studies. Our
previous study of endoscopic cartilage myringoplasty performed on CSOM
patients achieved a healing rate of 97.4% in dry ear group and 96.9%
in wet ear group (10). However, the small tympanic membrane residue of
large perforation and anterior-inferior perforation provides less or no
support to the graft and makes it difficult for the graft to tightly fit
the tympanic membrane. A national multicenter study showed that the
healing rate of large perforations was only 89.2%, much lower than
those of small and medium perforations (100.0% and 93.7%,
respectively). In terms of location, anterior perforations had the
lowest healing rate of 92.4%, compared to 94.9% of inferior
perforations and 95.6% of the posterior perforations (5).
In order to improve the healing rate of large,sub-total and
anterior-inferior perforations, some scholars used the tympanic
epithelial flap to repair marginal perforations and achieved a healing
rate of 96.3% (6). However, this method only improves the healing rate
of perforations no larger than 4 mm and critically depends on operators’
skills. Anterior wall flap separating were also applied to repair the
marginal perforations and reported 100% heal of perforations, but it is
only applicable for anterior (7).Different studies using butterfly
cartilage reported healing rates of 96% (11) and 88% (8). This method
improves the healing rate, but the high healing rate also heavily relies
on surgeons’ skills. Due to the lack of precise measuring tools for
tympanic perforation, the perforation size can only be roughly estimated
by the operator, leading to inappropriate size of trimmed butterfly
cartilage. Another drawback of butterfly cartilage method is the high
risks in induced tympanitis, with reported incidence varying from 5% to
14% (12).
In order to improve the surgical outcome of patients with poor
prognostic factors, we further enhanced
the contact between graft and
tympanic membrane remnant by adding an extra perichondrium patch
anterior-inferior to a graft made of tragal cartilage perichondrium
complex. We performed this procedure on patients with preoperative
eustachian tube dysfunction, and patients with large or
anterior-inferior marginal perforations whose grafts did not tightly fit
the tympanic membrane during operation. This patch can be easily
obtained by stripping perichondrium and cartilage on the parotid gland
side of the well-prepared cartilage. Once the surgeon develops graft
placement skills, this extra patching procedure can be completed within
1-3 minutes, without prolonging the operation or increasing patient
financial burden. Patients in our study exhibited significant
improvement in hearing after surgery, with both of the average PTA and
the ABG significantly reduced six months after operation.
Although our method of adding an extra patch is easy to operate,
surgeons’ skill is still critical. Improper operation may affect patch
survival and a bulky patch may block the pharyngeal orifice of
eustachian tube. There are some tips of adding an extra patch to
reinforce the graft: (1) The perichondrium strip should be trimmed to
2-3 mm in width. (2) The prepared patch should be delivered to
anterior-inferior area of the graft using forceps, and then a crochet
hook should be used to fold the patch inward between the graft and the
residual tympanic membrane to make the patch fit tightly with the graft
surface, the anterior-inferior edge of the graft and the residual
tympanic membrane. (3) If the fissure along the graft edge is large, a
cartilage patch can be placed at the fissure firstly, before placing the
perichondrium patch. Once the patching procedure is completed, gelatin
sponge can be used to remove surface secretions. Operators can slightly
press the gelatin sponge to smooth the patch and graft surface, and
further check hidden fissures underneath.
This method benefits patients in the following situations. Firstly,
patients who have eustachian tube dysfunction will benefit, because they
are more prone to anterior-inferior fissures due to possible negative
middle ear pressure. Secondly, this method will improve healing rates in
patients who have no residual tympanic membrane to support the graft, or
those whose tympanic membrane remnant does not closely fit the graft due
to various reasons such as too small graft, graft of poor shape, or
impossibility to retake a graft. In this case, an extra patch can be
easily obtained by trimming the parotid perichondrium or the remaining
cartilage. Thirdly, some patients have tympanic chamber left empty, and
the grafts without anterior-inferior support could not closely fit the
tympanic membrane. An extra patch offers additional support to the
graft. Fourthly, for low-income patients who cannot afford biological
materials or a secondary surgery, this method provides an affordable
alternative.