Abstract
In India, Chronic suppurative otitis media (CSOM) is a general public health issue leading to hearing loss which can be corrected surgically by Tympanoplasty. By applying predictors for a successful surgery the effectiveness of the surgery can be improved. In this study we aim to determine the usefulness of prognostic factors in predicting outcome of surgery for better patient compliance. 1. To compare MERI scores and saccharin test time in predicting graft uptake and hearing outcomes in Tympanoplasty surgery. A prospective study included all cases of mucosal type of CSOM of either sex according to the inclusion and exclusion criteria. Saccharin clearance time was used to assess Eustachian tube function and Pure Tone Audiometry has been done Pre-operatively to assess Hearing. Risk categories were assigned using MERI scoring chart and severity of disease assessed by otomicroscopy during surgery. Patients were post-operatively followed up to 6 months. Outcomes were assessed using Graft uptake, Hearing improvement and for recurrence of infection, compared with different categories of MERI and Saccharin time. The overall graft uptake was 96.6%. 100% successful graft uptake was seen among normal eustachian tube function. Hearing improvement after surgery may be predicted by saccharin and MERI test. Abnormal Saccharin test shows guarded prognosis in predicting the success of middle ear surgeries. Based on the MERI score and saccharin clearance time, hearing benefit and Surgical success can be assessed and patients can be counselled prior surgery regarding the expected outcome.
Keywords: Graft uptake, Hearing benefit, Saccharin test, Tympanoplasty, Middle ear risk index
Introduction
In India, CSOM is the general public health issue [1]. The target of surgery is to eradicate the disease and to restore hearing [2].
If there's a technique to predict the end result of the surgical procedure, the effectiveness of the surgery may be improved. Hence MERI (Middle Ear Risk Index) along with Saccharin test were used to stratify the severity of disease.
The aim of this research is to determine the usefulness of prognostic factors in predicting outcome of surgery for better patient compliance. Thus to compare MERI score and Saccharin test time in predicting graft uptake and hearing outcomes in Tympanoplasty surgery and to determine which among them is better, as a prognostic indicator.
Materials and Methods
The research has been performed at Department of ENT, Ramaiah Medical College Hospital, Bangalore, Karnataka, India during the period from September 2018 to March 2020.
It was a Prospective study conducted on patients who satisfied the inclusion Criteria. Ethical clearance was obtained for the study. A written consent was obtained from the patients for participation.
Inclusion criteria
Patient diagnosed with unilateral or bilateral mucosal type of chronic otitis media.
Patients between 12 to 60 years of age.
Exclusion criteria
Patient with known complications of chronic otitis media.
Patient with pre-existing nasal pathology.
Sample size: Sample size has been calculated based on previous research conducted by Aftab Ahmed and Satish Chandra Sharma within which it had been found that in mean audiological gain in MERI with patients with dry ear was 9.2 + 2.7(Moderate Risk). In present study, considering Absolute precision of 0.6 and confidence level of 95%, Sample size was calculated to be minimum of 81, 90 patients have been involved in the research.
All patients have been subjected to following investigations:
Pure tone audiogram,
Eustachian tube function test by Saccharin test,
Otomicroscopy,
Mastoid X ray or HRCT temporal bone.
Method
All cases of mucosal type of CSOM of either sex according to exclusion and inclusion criteria have been enrolled. A written consent for participation was obtained. Detailed history was taken followed by Throat, Nose, Ear examination along with general physical examination. The routine investigations required for surgery were done.
Patients with discharging ear have been conservatively given Antihistamines, Antibiotics, Topical Ear drops and Decongestants.
Saccharin test was performed pre-operatively; Saccharin clearance time is used to assess Eustachian tube function. Saccharin pellet is placed in middle ear cavity through perforation. The time for the patient to taste saccharin was classified into three groups (Fig. 1).
Fig. 1.
Showing saccharin test time classification
Taste sensation of tongue was tested if the time exceeds 45 min. If taste was intact, then response was taken as gross dysfunction. If sensation wasn't intact, then was taken as no response.
Pure Tone Audiometry has been done Pre-operatively for assessing Hearing loss. Hearing at 2000 Hz, 1000 Hz, and 500 Hz frequencies has been used to compute the air–bone gap, bone conduction threshold, and air conduction threshold.
Risk categories have been assigned using MERI scoring chart (Table 1) and severity of disease has been assessed by otomicroscopy during Surgery.
Table 1.
Showing meri score
| Sl. no | Risk factor | Risk value |
|---|---|---|
| 1 | Otorrhea | |
| I Dry | 0 | |
| II Occasionally wet | 1 | |
| III Persistently wet | 2 | |
| IV Wet, cleft palate | 3 | |
| 2 | Perforation | |
| Absent | 0 | |
| Present | 1 | |
| 3 | Cholesteatoma | |
| Absent | 0 | |
| Present | 2 | |
| 4 | Ossicular status | |
| O: M + I + S + | 0 | |
| A: M + S + | 1 | |
| B: M + S − | 2 | |
| C: M − S + | 3 | |
| D: M − S − | 4 | |
| E: Malleus head fixation | 2 | |
| F: Stapes fixation | 3 | |
| 5 | Middle ear granulation or effusion | |
| Yes | 2 | |
| NO | 0 | |
| 6 | Previous surgery | |
| None | 0 | |
| Staged | 1 | |
| Revision | 2 | |
| 7 | Smoker | |
| No | 0 | |
| Yes | 2 |
MERI 0: Normal, MERI 1–3: Mild disease, MERI 4–6: Moderate disease, MERI 7–12: Severe disease
After an intensive pre-operative and pre-anaesthetic check-up, the patients were posted for surgery. To provide a uniform intraoperative environment for all patients, all surgeries were performed under General Anaesthesia utilising post-auricular technique.
The decision for performing mastoidectomy has been taken by the operating surgeon after noting the intraoperative findings. For Ossiculoplasty Autografts were used depending on the ossicular status. The temporalis fascia graft placed by an underlay technique. The patients were discharged on the third day with oral antibiotics, antihistamines and analgesic therapy. Patients were given post-surgery instructions on how to keep their ears dry, avoid flying at low and high altitudes and avoid sneezing.
Follow up of patient’s post-surgery was done on 7, 15, 28 days and up to 6 months for graft uptake and Hearing assessed by Tuning fork tests and audiometry after 6 months.
Outcome was assessed using Subjective improvement, Graft uptake, Mean Audiological gain taking average readings of 500, 1000 and 2000 Hz and compared with different categories of MERI and Saccharin time. The results of the procedure were evaluated in the postoperative phase, which was classified into the following categories: (a) Successful—the healed graft with proper middle ear aeration. (b) perforation of graft or Graft failure. Saccharin and MERI tests were compared with postoperative and preoperative air bone gaps.
Statistical Analysis
The comparison between hearing outcome, MERI categories and saccharin test were carried out using ANOVA Test or KRUSKAL WALLIS test. In order to investigate the correlation between the two variables, non-parametric tests (Spearman Correlation) were utilised, and Paired Wilcoxon test has been used to investigate the difference test. Tests for categorical variables have been carried out utilizing CHI-SQUARE test.
Results and Analysis
There were 90 patients in the research. 74 patients had unilateral ear pathology and 16 patients had bilateral ear pathology. Thirty seven patients underwent right ear surgery and 53 patients in left ear.
The age distribution among the study group ranged between 12 and 70 years. Maximum patients ranged between 21 to 40 years (Fig. 2).
Fig. 2.
For age distribution
The overall graft uptake was 96.6%. A total of 3.4 percent of the grafts were deemed unsuccessful because they were perforated or rejected.
While considering MERI scores, good Graft uptake was seen in 100% of the participants within the group of Mild Disease, 93.1% of the participants within the group of Moderate Disease and 88.9% of the participants within the group of Severe Disease had good graft uptake. (Table 2).
Table 2.
For meri score and graft uptake
| Graft uptake | MERI category | |||
|---|---|---|---|---|
| Mild disease | Moderate disease | Severe disease | Total | |
| Good | 52 (100%) | 27 (93.1%) | 8 (88.9%) | 87 (96.7%) |
| Failed | 0 (0.0%) | 2 (6.9%) | 1 (11.1%) | 3 (3.3%) |
| Total | 52 (100.0%) | 29 (100.0%) | 9 (100.0%) | 90 (100.0%) |
While considering Saccharin Test time, 100% successful graft uptake was seen among normal and partial dysfunction of eustachian tube function on saccharin test and 11.8% of the participants with Gross Dysfunction on saccharin had failed graft uptake. The study almost reached significance (p value = 0.051); a trend was observed (Table 3).
Table 3.
For saccharin test and graft uptake
| Graft uptake | Saccharin test | |||
|---|---|---|---|---|
| Normal | Partial Dysfunction | Gross Dysfunction | Total | |
| Good | 49 (100.0%) | 23 (100%) | 15 (88.2%) | 87 (96.7%) |
| Failed | 0 (0.0%) | 0(0.0%) | 3 (11.8%) | 3 (3.3%) |
| Total | 49 (100.0%) | 23 (100.0%) | 18 (100.0%) | 90 (100.0%) |
An average postoperative air–bone gap closure of 20 dB or less has been deemed effective in our research, which included 85.5 percent of patients who had their hearing improved at frequencies of 2 kHz, 1 kHz, and 500 Hz.
A moderate positive correlation has been seen between pre-op AC (dB), Air Conduction (dB) (6 Months), AB Gap (dB) (Pre-Operative) and MERI Score, and this correlation has been statistically significant (rho = 0.5, p = < 0.001). For every 1 unit increase in MERI Score, the Air Conduction (dB) (Pre-Operative) increases by 2.49 units, the Air Conduction (dB) (6 Months) increases by 1.62 units and the AB Gap (dB) (Pre-Operative) increases by 1.51 units (Table 4).
Table 4.
Comparison of Meri score in terms of change in ab gap (db) over time
| AB gap (dB) | MERI category | P value for comparison of the three groups at each of the timepoints (Kruskal Wallis Test) | ||
|---|---|---|---|---|
| Mild disease | Moderate disease | Severe disease | ||
| Mean (SD) | Mean (SD) | Mean (SD) | ||
| Pre-Operative | 22.66 (7.83) | 26.22 (7.39) | 31.62 (7.05) | 0.004 |
| 6 Months | 8.92 (5.16) | 11.47 (7.52) | 16.25 (4.95) | 0.005 |
| P Value for change in AB Gap (dB) over time within each group (Wilcoxon Test) | < 0.001 | < 0.001 | 0.008 | |
| Overall P Value for comparison of change in AB Gap (dB) over time between the three groups (Generalized Estimating Equations) | 0.688 | |||
A significant difference has been seen between the MERI score and AB Gap (dB) (6 Months) (χ2 = 10.747, p = 0.005), with the median AB Gap (dB) (6 Months) being highest among severe category of MERI. Thus, the pre-operative and post-operative hearing outcome after middle ear surgery can be predicted using MERI score.
With Saccharin test, significant difference is there between these three groups in terms of AB Gap (dB) (6 Months) (χ2 = 8.227, p = 0.016), with the AB Gap (dB) (6 Months) being highest with Gross Dysfunction group. No significant difference has been seen within the trend of AB Gap (dB) over time between the three groups (p = 0.931) (Table 5).
Table 5.
Comparison of the three groups in terms of change in ab gap (db) over time (N = 90)
| AB Gap (dB) | Saccharin test | P value for comparison of the three groups at each of the timepoints (Kruskal Wallis Test) | ||
|---|---|---|---|---|
| Normal | Partial dysfunction | Gross dysfunction | ||
| Mean (SD) | Mean (SD) | Mean (SD) | ||
| Pre-Operative | 22.98 (8.06) | 24.33 (6.73) | 29.66 (7.94) | 0.011 |
| 6 Months | 8.95 (4.65) | 9.71 (5.60) | 15.53 (8.82) | 0.016 |
| P Value for change in AB Gap (dB) over time within each group (Wilcoxon Test) | < 0.001 | < 0.001 | < 0.001 | |
| Overall P Value for comparison of change in AB Gap (dB) over time between the three groups (Generalized Estimating Equations) | 0.931 | |||
There is a good correlation between MERI score and saccharin test, higher MERI score corresponded to gross dysfunction in saccharin test which was statistically significant (χ2 = 40.807, p = < 0.001) (Tables 6, 7).
Table 6.
Comparison of the saccharin test in terms of meri score
| MERI score | Saccharin test | Kruskal Wallis test | |||
|---|---|---|---|---|---|
| Normal | Partial dysfunction | Gross dysfunction | χ2 | p value | |
| Mean (SD) | 2.55 (1.17) | 3.71 (1.46) | 6.12 (1.87) | 40.807 | < 0.001 |
| Median (IQR) | 2 (2–3) | 4 (2.75–4) | 6 (5–7) | ||
| Range | 1–7 | 2–7 | 4–11 | ||
Table 7.
Comparison of hearing parameters by saccharin test and meri score
| Parameters | MERI category | p value | ||
|---|---|---|---|---|
| Mild disease (n = 52) | Moderate disease (n = 29) | Severe disease (n = 9) | ||
| Air Conduction (dB) (Pre-Operative)*** | 39.78 ± 9.59 | 50.19 ± 11.89 | 47.50 ± 8.12 | < 0.0011 |
| Bone Conduction (dB) (Pre-Operative)*** | 16.74 ± 7.35 | 23.63 ± 10.37 | 15.88 ± 3.04 | 0.0111 |
| AB Gap (dB) (Pre-Operative)*** | 22.66 ± 7.83 | 26.22 ± 7.39 | 31.62 ± 7.05 | 0.0041 |
| Air Conduction (dB) (6 Months)*** | 26.20 ± 7.49 | 34.69 ± 10.37 | 30.75 ± 5.75 | < 0.0011 |
| Bone Conduction (dB) (6 Months)*** | 17.35 ± 7.30 | 23.50 ± 10.05 | 15.75 ± 3.11 | 0.0171 |
| AB Gap (dB) (6 Months)*** | 8.92 ± 5.16 | 11.47 ± 7.52 | 16.25 ± 4.95 | 0.0051 |
| Change in AB Gap (dB) | 13.34 ± 6.71 | 14.74 ± 7.59 | 15.38 ± 6.02 | 0.4881 |
| Parameters | Saccharin test | p value | ||
|---|---|---|---|---|
| Normal (n = 49) |
Partial dysfunction (n = 23) |
Gross dysfunction (n = 18) |
||
| Air Conduction (dB) (Pre-Operative)*** | 40.03 ± 10.30 | 45.18 ± 9.27 | 52.82 ± 11.61 | < 0.0012 |
| Bone Conduction (dB) (Pre-Operative)*** | 16.84 ± 7.62 | 20.43 ± 9.38 | 22.56 ± 9.84 | 0.0441 |
| AB Gap (dB) (Pre-Operative)*** | 22.98 ± 8.06 | 24.33 ± 6.73 | 29.66 ± 7.94 | 0.0112 |
| Air Conduction (dB) (6 Months)*** | 26.38 ± 7.39 | 30.08 ± 7.62 | 36.82 ± 11.66 | 0.0011 |
| Bone Conduction (dB) (6 Months) | 17.51 ± 7.64 | 20.38 ± 9.07 | 22.35 ± 9.52 | 0.1061 |
| AB Gap (dB) (6 Months)*** | 8.95 ± 4.65 | 9.71 ± 5.60 | 15.53 ± 8.82 | 0.0161 |
| Change in AB Gap (dB) | 13.69 ± 6.82 | 14.43 ± 6.08 | 14.14 ± 8.55 | 0.7481 |
***Significant at p < 0.05, 1: Kruskal Wallis Test, 2: One-Way ANOVA
Discussion
Conductive hearing loss is the most typical pattern of hearing impairment in CSOM which causes communication problems, thus affects social and personal living [1]. To the patient a successful surgery means dry ear with good hearing.
The definitive treatment for CSOM involves surgery- Tympanoplasty with or without Mastoidectomy [3]. The main goal of surgery is to eliminate the infection and establish a dry and safe environment for the patient's ear. CSOM surgery also aims to keep hearing at a reasonable level with tympanoplasty [2].
The success rate of surgery is measured by the incidence of ears becoming dry and noticeable hearing improvement. Various significant clinical investigations have shown it to be anywhere from 70 to 90% effective [4, 5].
There are multiple factors which contribute to success rate of Middle ear surgery. The efficacy of surgery may be enhanced if the middle ear is in a pathological state [6]. As a result, patient compliance steadily improves. An evaluation of prognostic variables is thus necessary.
Disease status may be determined by utilizing MERI “Middle Ear Risk Index”. MERI score is calculated by allocating a numerical value to each of the risk factors.
This surgery's outcome is dependent on the Eustachian tube's ability to operate regularly as part of the body's normal middle ear cavity and hearing. Pathological changes in middle ear like retraction pocket of eardrum which may evolve into cholesteatoma and high complications can occur because of impaired Eustachian tube function [7]. Dysfunction may additionally cause failure of graft uptake and need revision surgery. Eustachian tube function is measured by mucociliary clearance using saccharin test time [8].
It was thus decided to investigate whether or not the results of this research could be utilised to accurately predict the outcome of surgery based on saccharin test time and MERI score.
The disease level in the mastoid as well as middle ear has been taken into consideration while deciding on the kind of tympanoplasty procedure. If there was simply a dry central perforation, mastoidectomy has been avoided and type 1 tympanoplasty has been performed. Based on the level of ossicular erosion, ossiculoplasty has been performed. Several patients had their residual ossicles reshaped and used as ossicular grafts, whereas conchal cartilage has been used on a small number of individuals. In 14 cases studied, the incus has deteriorated (15.6 percent), it is one of the most often eroded bones. Ossicular fixation has not been seen in our research.
Patients with a lower MERI score had improved pre- and post-operative air and bone conduction, according to studies by Viktor Chrobok et al. [9] The results of Viktor Chrobok's research, on the other hand, support our conclusions.
There is a decent correlation between MERI score and saccharin test, higher MERI score corresponded to gross dysfunction in saccharin test which was statistically significant in our study which was in concordance in other study conducted by Nishant et al. [6]
Conclusion
MERI and saccharin test are good prognostic factors for middle ear surgeries. Saccharin test shows better prognosis in predicting the success of graft uptake. Patients with lower MERI scores see a higher improvement in their hearing after surgery. All patients undergoing middle ear surgery must have their Eustachian tube function tested prior to surgery. The Eustachian tube's mucociliary activity may be measured using a simple and inexpensive test called the saccharin test. The graft uptake rate is lower and improvement in hearing is poorer the longer the mucociliary clearance time. Hence the saccharin clearance time and MERI score may be used to establish the surgical objectives, surgical success, and hearing benefit prior to surgery. Thus Saccharin test is better prognostic indictor. Hence the saccharin clearance time can be used to establish the surgical objectives, surgical success, and hearing benefit prior to surgery and patients could be counselled about the expected benefits of surgical management.
Declarations
Conflict of interest
None.
Footnotes
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References
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