THE EFFECT OF MIDDLE EAR RISK INDEX (MERI) ON THE PROGNOSTIC

SUCCESS OF TYMPANOMASTOIDECTOMY IN
CHRONIC SUPPURATIVE OTITIS MEDIA (CSOM)

ABSTRAK

Latar Belakang: Otitis Media Supuratif Kronis (CSOM) diperkirakan terjadi pada 65-300 juta penduduk dengan
60% kasus CSOM disertai adanya gangguan pendengaran. Angka kejadian CSOM cukup tinggi pada negara
berkembang. Pembedahan merupakan salah satu manajemen yang dipertimbangkan pada kasus CSOM dengan
tujuan mengeradikasi penyakit dan menjadikan telinga aman dan kering. Middle Ear Risk Index (MERI) dirancang
untuk dapat membantu dalam menilai prognosis dari timpanoplasti. Informasi terkait prognosis merupakan suatu
hal yang penting dalam mengambil keputusan klinis.
Tujuan: Untuk mengetahui menilai pengaruh MERI terhadap prognostik keberhasilan timpanomastoidektomi pada
pasien CSOM
Metode: Penelitian analitik obervasional dengan desain potong lintang. Sampel penelitian diambil berdasarkan
teknik total sampling pada pasien CSOM yang menjalani prosedur timpanomastoidektomi di RSUD dr. Zainoel
Abidin Banda Aceh pada Januari 2021 hingga Desember 2022. Keberhasilan timpanomastoidektomi dinilai dengan
audiometri nada murni, penyembuhan graft dan gejala otorea.
Hasil: Penelitian ini menunjukkan adanya hubungan antara skor MERI terhadap keberhasilan
timpanomastoidektomi (p< 0,05). MERI merupakan alat prognostik yang baik dalam memprediksikan penyembuhan
graft (area under curve (AUC) 0,908; cut-off 6 menunjukkan sensitivitas 85,7% dan spesifisitas 81,1%), perbaikan
audiometri nada murni (AUC 0,908; cut-off 5 menunjukkan sensitivitas 69,3% dan spesifisitas 75,0%) dan
kemungkinan terjadinya otorea (AUC 0,908; cut-off 6 sensitivitas 85,7% dan spesifisitas 81,1%
Diskusi: Penilaian MERI dapat menjadi pemeriksaan yang bermanfaat dalam memprediksikan luaran klinis paska
timpanomastroidektomi. Penilaian MERI dapat dipertimbangkan untuk digunakan sebagai dasar dalam
pengambilan keputusan klinis.
Kata Kunci: Middle Ear Risk Index (MERI), Otitis media supurativa kronis, Timpanomastoidektomi.

ABSTRACT

Background: Chronic Suppurative Otitis Media (CSOM) is estimated to affect 65-300 million individuals, with 60%
of CSOM cases associated with hearing impairment. The prevalence of CSOM is significantly elevated in
developing nations. Surgery is a management option investigated in CSOM patients, aimed at eradicating the
disease and ensuring the ear is safe and dry. The Middle Ear Risk Index (MERI) is intended to assist in evaluating
the prognosis of tympanoplasty. Prognostic information is crucial for clinical decision-making.
Objective: To evaluate the impact of MERI on the prognostic outcomes of tympanomastoidectomy in patients with
CSOM.
Methods: Observational analytical research with a cross-sectional design. The research sample was derived using
total sampling from CSOM patients who underwent tympanomastoidectomy at Dr. Zainoel Abidin Banda Aceh
Hospital between January 2021 and December 2022. The efficacy of a tympanomastoidectomy is evaluated using
pure tone audiometry, graft integration, and otorrhea symptoms.
Results: This study demonstrated a correlation between the MERI score and the efficacy of tympanomastoidectomy
(p< 0.05). MERI serves as an effective prognostic instrument for forecasting graft healing (area under curve (AUC)
0.908; cut-off 6 demonstrates sensitivity 85.7% and specificity 81.1%), enhancement in pure tone audiometry (AUC
0.908; cut-off 5 demonstrates sensitivity 69.3% and specificity 75.0%), and the probability of otorrhea (AUC 0.908;
cut-off 6 demonstrates sensitivity 85.7% and specificity 81.1%).
Discussions: The MERI assessment may effectively predict clinical outcomes following tympanomastoidectomy. The
MERI assessment may serve as a foundation for clinical decision-making.
Keywords: Middle Ear Risk Index (MERI), Chronic suppurative otitis media (CSOM), Tympanomastoidectomy,
Prognostic factors
Correspondence: Mus, Department of Otorhinolaryngology - Head and Neck Surgery, Faculty of Medicine, Syiah Kuala
University, Dr Zainal Abidin Hospital
INTRODUCTIOIN

The incidence of CSOM worldwide is estimated to range from 65 to 300 million cases with 60%
of CSOM cases accompanied by hearing loss. Meanwhile, the prevalence of CSOM in Indonesia
is 3.0–5.2% or there are around 6.6 million people in Indonesia who experience CSOM. The
high incidence of CSOM in developing countries is due to low socioeconomic factors, low
knowledge of the importance of health and poor nutritional status in the community. According
to WHO, a prevalence of CSOM of more than 4% indicates a critical health problem in a
country.

There are a number of factors that affect the success rate of tympanoplasty such as patient age,
size and location of perforation, ear status (dry or wet), ossicular status and surgical technique,
but their real role is still unclear. Therefore, the success rate of tympanoplasty, as reported, can
range from 35% to 92%.5.6,7

Various scoring systems have been developed for the evaluation of middle ear disease. The
Middle Ear Risk Index (MERI) is a commonly used scoring system. MERI is a numerical
assessment of middle ear health. The MERI score is determined by assigning a specific value to
each risk factor, and these values are added to obtain a global result. 8 Risk factors include the
Belluci criteria for assessing the degree of otorrhea, the Austin/Kartushus criteria for ossicular
status, the presence of perforation, middle ear granulating cholesteatoma/effusion, and previous
surgical history. Risk categories are grouped from the MERI as follows: (0 = normal; 1-3 = mild;
4-6 = moderate; 12 = severe). 2

Table. Index MERI

Shishegar et al stated that MERI score is an important assessment in predicting the success of
tympanoplasty and helps the operator in determining the type of tympanoplasty. Carlos et al's
study showed that moderate MERI is a protective factor from surgical failure (OR 0.24; 95% CI
0.07-0.71; p = 0.002) and severe MERI is a predictor of unsuccessful tympanoplasty surgery
(OR 5.87; 95% CI 1.92 - 18.57; p = 0.003). 2 A study by Chrobok et al showed that patients with
low MERI scores were associated with better pre and postoperative bone conduction (p <0.05).
6,14

MATERIAL AND METHODS

This study includes an observational analytical study with a cross-sectional approach to analyze
the relationship between the Middle Ear Risk Index (MERI) and the prognostic success of
tympanomastoidectomy in patients with chronic suppurative otitis media (CSOM). Data
collection was carried out from the THTBKL polyclinic and medical records of OMSK patients
who underwent tympanomastoidectomy at the dr. Zainoel Abidin Banda Aceh Regional Hospital
(RSUDZA) from January 2021 to December 2022. Patient data was collected from the issuance
of the results of the ethical review protocol approval until all data was collected.
The study comprised of 81 patients suffering from chronic otitis media with or without cholesteatoma.
The age of patients ranged from 19 to 60 years and male to female sex ratio of 1.5:1. The patients were
subjected to detailed history, general as well as systemic examination, which includes clinical
examination of the ear, nose, paranasal sinuses, larynx and pharynx. The complete otological evaluation
has been done to assess the exact nature and extent of disease, presence or absence of otorrhea,
cholesteatoma, granulation tissue, mucosal polyp and ossicular chain status. Pure tone audiometry was
performed to assess the type and degree of hearing loss. The Hughson and Westlake method modified
by Carhart and Jerger was used to calculate the hearing loss. The mean air-bone gap was measured from
the air and bone conduction thresholds at 0.5 kHz, 1 kHz, 2 kHz, and 3 kHz Complete laboratory
evaluation was done and radiological evaluation was done if needed.

In this study, the majority of OMSK patients who underwent tympanomastoidectomy at RSUDZA from
January 2021 to December 2022 were male (51 samples; 63%), young adults (47 samples; 58.0%),
showed complaints > 4 years (58 samples, 71.6%) and with mixed deafness (40 samples; 49.4%) and
followed by conductive deafness in 46.9% of the study samples (38 samples).

PROCEDURE

According to the examination and CT temporal scan findings, the type of tympanoplasty and
tympanomastoidectomy to be performed was planned but could be modified according to the extent of
the disease and the ossicular status intraoperatively. For the graft, temporalis fascia autograft was used
in all the patients. Patients has been reviewed for 1 month and then once a month for next 3 months,
and afterward, patients were seen every 6 months.

The outcome of surgery was based on two factors:

1. Graft status

2. Pure tone audiometry

3. Otorrhea

Graft status was assessed using otoscopic examination.

• Successful – healed graft and no otorrhea

• Pure-tone audiometry was done at the end of 3 months postoperatively. Hearing benefit was
calculated based on the difference between preoperative and postoperative air-bone gaps. increased
hearing threshold and air bone gaps ≤10 dB

RESULTS

Data collection was conducted from March to July 2024 at RSUDZA. Data collection was carried out after
obtaining ethical approval from the Health Research Ethics Committee (KEPK) of Dr. Zainoel Abidin
General Hospital. Eighty-one research samples met the inclusion criteria and met the exclusion criteria.
The data obtained were then analyzed statistically using SPSS 24.0.

There are 81 samples that are the research samples. The characteristics of this research sample are
shown in table 5.1.

Table 5.1 Frequency Distribution of Research Sample Characteristics

Characteristics n %
 Gender
Male 51 63,0
Female 30 37,0
Usia
Children (<19 tahun) 12 14,8
Young Adults (19-39 tahun) 47 58,0
Middle-Aged Adults (40-59 tahun) 20 24,7
Elderly (≥60 tahun) 2 2,5
Duration of Complaints (Years)
<1 8 9,9
2 10 12,3
3 5 6,2
>4 58 71,6
Type of Deafness
conductive 38 46,9

Mixed 43 53,1
Total 81 100,0

In this study, the majority of OMSK patients who underwent tympanomastoidectomy at RSUDZA from
January 2021 to December 2022 were male (51 samples; 63%), young adults (47 samples; 58.0%),
showed complaints > 4 years (58 samples, 71.6%) and with mixed deafness (43 samples; 53,1%) and
followed by conductive deafness in 46.9% of the study samples (38 samples).

Table 5.2 MERI Score in OMSK patients undergoing Tympanomastoidectomy

Skor MERI n %
Mild 24 29,6
Moderate 33 40,7
Severe 24 29,6
Total 81 100,0

The majority of OMSK patients undergoing tympanomastoidectomy at RSUDZA showed moderate MERI
(40.7%) followed by mild scores and severe MERI 29.6%.

Table Graft status according to MERI score category

Success of Tympanomastoidectomy
Total
MERI Score Taken up Rejected p-value
n % n % n %
Mild 23 95,8 1 4,2 24 100,0
Moderate 25 75,8 8 24,2 33 100,0 0,005
Severe 5 20,8 19 79,2 24 100,0
Table Otorrhea status according to MERI score category

Success of Tympanomastoidectomy
Total
MERI Score Taken up Rejected p-value
n % n % n %
Mild 23 95,8 1 4,2 24 100,0
Moderate 25 75,8 8 24,2 33 100,0 0,005
Severe 5 20,8 19 79,2 24 100,0

Table : Gain hearing according to MERI score category

Success of Tympanomastoidectomy
Total
MERI Score Taken up Rejected p-value
n % n % n %
Mild 8 33,3 16 66,7 24 100,0
Moderate 10 30,3 23 69,7 33 100,0 0,005
Severe 2 8,3 22 91,7 24 100,0

DISCUSSION

The majority of the study samples were male (51 samples; 63%). Research by Putu et al. showed that
the distribution of OMSK was more common in male patients (56.16%). Research by Abraham et al.,
showed that OMSK patients were slightly more male (54.4%). 16 A study by Chung et al., in Korea showed
that OMSK was more common in women (p = 0.14). 56 Meta-analysis by Heward et al. showed that male
gender was not a risk factor for OMSK (Relative Risk (RR) = 0.96 [0.82–1.13], p = 0.62, from 8 studies). 57
A study by Gina Novian et al., at Al Ihsan Hospital in 2018 found that 56.68% of all samples were male. 58

In this study, OMSK was more dominated by men because men are more exposed to environmental
contaminants, pollution or cigarette smoke, which can increase the possibility of infection, lack of
maintaining cleanliness and the majority live in coastal areas where they usually bathe in rivers or the
sea.