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ORIGINAL ARTICLE
Year : 2022 | Volume
: 28
| Issue : 3 | Page : 198-203
Ossiculoplasty outcome parameter staging index as a prognostic factor in ossiculoplasty
Aftab Ahmed, Danish Ahmad Khan, Satish Chandra Sharma
Department of Otorhinolaryngology, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
Correspondence Address:
Dr. Aftab Ahmed
Department of Otorhinolaryngology, J. N. Medical College, Aligarh Muslim University, Aligarh - 202 002, Uttar Pradesh
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/indianjotol.indianjotol_122_21
Aims: To evaluate the prognostic value of Ossiculoplasty Outcome Parameter Staging (OOPS) index with reference to the audiological outcome in the patients undergoing ossiculoplasty. Study Design: A prospective study. Setting: A tertiary referral hospital. Subjects: The study comprised 118 patients suffering from chronic otitis media with or without cholesteatoma. Materials and Methods: Ossiculoplasty was done by autologous incus interposition, partial ossicular prosthesis, and total ossicular prosthesis. Temporalis fascia graft was used for myringoplasty in all the patients. When partial ossicular replacement prosthesis or total ossicular replacement prosthesis was used a thin slice of cartilage was interposed between graft and prosthesis. The mastoidectomy was performed when needed, and whenever possible, a canal wall-up procedure was performed. Results: The short-term (measured after 3 and 6 months of surgery) and long-term (measured at 1 and 2 years after surgery) outcome of ossiculoplasty measured as a relationship between mean audiological gain and OOPS index score had a statically significant difference. Conclusion: The OOPS index is an appropriate prognostication index to predict accurately both the short- and long-term outcome of ossiculoplasty.
Keywords: Chronic otitis media, ossiculoplasty, Ossiculoplasty Outcome Parameter Staging index, partial ossicular replacement prosthesis, prognostic factors, total ossicular replacement prosthesis, tympanoplasty
The ossicular chain reconstruction aims to optimize the middle ear transformer mechanism, so that sound energy is conducted through middle ear with only minimal loss. The objective of ossiculoplasty is restoration of conductive mechanism of the middle ear that is sustainable for long term. The factors affecting the outcome of ossiculoplasty are middle ear pathology, surgical technique, and prosthesis design.[1],[2] The middle ear pathology is also known as middle ear environment and it is the most important factor affecting the outcome.[3] An understanding of middle ear pathology is the key to the proper reconstruction in ossiculoplasty. There have been various attempts to predict the appropriate surgical technique for ossiculoplasty and also finding the risk for long-term complications. However, developing a prognostication system that predicts both the short-term and long-term hearing results and the risk for long-term complications has been a difficult task. The reason for this difficulty is the heterogeneity of available study populations, relative lack of standardization for collecting the data and loss of patients during follow-up. The American Academy of Otolaryngology–Head and Neck Surgery 1995 guidelines should be kept in mind when reporting the results of tympanoplasty and ossiculoplasty.[4] These guidelines help us in overcoming the above-mentioned issues.
The ossicular chain disruption has been classified in four groups by Austin (Group A to D). This classification is based on the presence or absence of the malleus handle and the stapes suprastructure. The four types of the ossicular defects according to this classification are Type A (M+, S+), Type B (M+, S−), Type C (M−, S+), and Type D (M−, S−). The most common ossicular defect encountered is the erosion of long process of incus with intact malleus handle and stapes suprastructure (Type A), and this is followed by Types B, C, and D.[5] Three more categories added to this classification by Kartush are intact ossicular chain (0), fixation of the malleus head (E), and fixation of the stapes (F) as reported by Bloom et al., 2015.[6]
The technique used for ossiculoplasty depends on the remnant ossicular chain and its relationship to each other after complete removal of disease. A fitted or sculpted incus prosthesis is the best choice if the lenticular process of the incus is eroded and the manubrium is in proximity to the stapes superstructure (favorable relationship).[7] A sculpted incus placement is not recommended because of its inherent instability with the erosion of lenticular process of the incus and if the manubrium is positioned far anterior to the stapes superstructure (unfavorable relationship). The use of a partial ossicular replacement prosthesis (PORP) is a better option in such cases and has been reported to result in air–bone gap closure within 20 dB in large number of cases. A PORP can also be used in Type C defects (M−, S+). The repair of ossicular defect in both Type B (M+, S−) and Type D (M−, S−) can be done by use of a total ossicular replacement prosthesis (TORP). The short-term hearing results with both TORPs and PORPs are comparable, but the long-term results with TORPs are generally not as satisfactory as with PORPs because of instability of medial strut of the TORPs, as there is nothing to secure it into position at the center of the stapes. The base of the TORP can be stabilized by a cartilage shoe over the oval window and this improves the long-term audiological results.[8]
The major restrains for two staged surgical procedure in the developing countries are the cost of surgery and absence from the work. The cost-effectiveness of the surgery can be improved if we can predict the outcome of the surgical procedure depending on the pathological condition of the middle ear, and this will also improve the compliance of the patients. The pathological factors affecting the surgical outcome of COM have been highlighted by different authors time by time, but the factors have been analyzed separately and each study has concentrated only on one factor at a time.[9],[10] The study combining multiple factors is the Surgical, Prosthetic, Infection, Tissue, and Eustachian tube More Details (SPITE) method, has been very useful in the middle ear surgeries.[11] The Middle Ear Risk Index (MERI) is another index stratifying the patients according to the severity of the middle ear disease and it was described by Kartush. MERI score takes into consideration the presence or absence of otorrhea and cholesteatoma, tympanic membrane perforation, ossicular chain status (Austin–Kartush criteria), middle ear granulation, and previous surgery.[12] To predict hearing outcomes in ossiculoplasty, the Dornhoffer and Gardner in 2001[13] developed another index titled Ossiculoplasty Outcome Parameter Staging (OOPS) index [Table 1].
The OOPS index was originally devised for the prognostication of ossicular reconstruction in the context of the middle ear environment. This index is calculated on the basis of information obtained from the preoperative history and clinical examination records and the middle ear findings at the time of surgery taken from the operative report. The patients are categorized into three risk groups as low risk (OOPS index: 1–3), intermediate risk (OOPS index: 4–6), and high risk (OOPS index: 7–9) based on the OOPS index score. The objective of this study was to evaluate a group of patients undergoing ossiculoplasty with reference to the prognostic significance of OOPS index in predicting the audiological outcome of the ossiculoplasty both short and long term.
Materials and MethodsThis study was carried out at a tertiary referral hospital from December 2017 to July 2021. The study comprised 118 patients suffering from chronic otitis media with or without cholesteatoma. 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 was done to assess the exact nature and extent of disease, presence or absence of tympanosclerosis, cholesteatoma, granulation tissue, mucosal polyp, and ossicular chain status. Eustachian tube function was evaluated by Valsalva test and eustachian tube catheterization. Otomicroscopy was done and ossicular chain status was evaluated; however, the exact status of the ossicles was determined at the time of the surgery. Pure tone audiometry (PTA) was done for audiological evaluation and readings were taken at 500, 1000, 2000, and 4000 Hz and air–bone (AB) gap was calculated by taking average of above four frequencies. Complete laboratory evaluation was done and radiological evaluation was done if needed.
Our study included the patients suffering from unilateral or bilateral chronic otitis media with or without cholesteatoma and with adequate cochlear reserve. Our study excluded the patients younger than 12 years of age. The patients found to have systemic diseases, e.g., hypertension and diabetes mellitus, and the patients with adenotonsillitis, cleft palate, and nasal polyp were excluded from the study. The patients with intracranial complications of chronic otitis media were also excluded.
All the patients included in the present study were operated by the same surgeon and the surgical technique remained the same throughout the period of study. Temporalis fascia graft was used for myringoplasty in all the patients. Thin slice of autologous conchal cartilage was interposed between temporalis fascia graft and prosthesis, when PORP or TORP was used. The ossicular reconstruction technique was chosen based on the available ossicular remnants after the complete removal of the diseased tissues. Ossiculoplasty was performed in all 118 patients by any of the technique among autologous incus interposition, partial ossicular prosthesis, or total ossicular prosthesis. In the patients requiring mastoidectomy along with tympanoplasty, the mastoidectomy performed was of either canal wall-up (CWU) or canal wall-down (CWD) technique. In cholesteatoma surgery, whenever possible, a CWU procedure was performed. CWD technique was done in cases having extensive disease, erosion of the external auditory meatus, or revision surgery for extensive recurrent disease.
The postoperative management of the patients in our study was according to a predefined algorithm. This helped in the proper care of the patients after the surgery. The patients were reviewed after 1 week of surgery and mastoid bandage was removed. The second review was scheduled between 2 and 4 weeks after the surgery and otomicroscopic examination was performed. On examination, if the progress was satisfactory, the patients were reviewed after 3 months of the surgery and PTA was conducted. The patients having sustained improvement were reviewed again at 6 months, 1 year, and 2 years after surgery and audiometric evaluation was done. In the patients having unsatisfactory progress, intranasal corticosteroid sprays, and Valsalva maneuver for eustachian tube, exercise was advised and review was done on monthly basis.
A tympanostomy tube was placed through the graft if the patient had persistent middle ear effusion. Patients having poor hearing results and suspected of having displaced prosthesis were advised high-resolution computed tomography (CT) scan of the temporal bone. If the prosthesis was found to be displaced, exploratory tympanoplasty or revision ossiculoplasty was performed as indicated. In patients having suspicion of residual cholesteatoma, high-resolution CT scan was done and second look surgery was performed.
The outcome measure in our study was mean audiological gain measured at 3 months, 6 months, 1 year, and 2 years postoperatively. The mean audiological gain at 3 and 6 months was considered to be short-term outcome, whereas the mean audiological gain at 1 and 2 years of the surgery was taken to be long-term outcome. This was according to the 1995 American Academy of Otolaryngology–Head and Neck Surgery reporting guidelines, which defines the short-term outcome as <1 year and long-term outcome as more than 1 year postoperative follow-up. The audiological gain was calculated for each patient by subtracting the postoperative AB gap from the preoperative AB gap. The mean audiological gain was calculated for each group by dividing the sum of audiological gain in that group by the total number of cases in the same group. The AB gap closure to ≤20 dB was taken as successful outcome of ossiculoplasty.
The OOPS index was calculated for each patient and they were grouped into low-risk (1–3), intermediate-risk (4–6), and high-risk (7–9) categories based on OOPS index score. The mean audiological gain in group of the patients having low-, intermediate-, and high-risk OOPS index was calculated and compared for their statistical significance. As most of the patients in the present study were from rural area, they do not return for follow-up once they have improvement after the surgery. This has been the reason for loss to follow-up in our study and also for more long term follow-up of the patients.
In this study, before including the patients, written informed consent was taken from the patients or guardian (in case of minor). This study was carried out in accordance with the ethical guidelines for biomedical research on human subjects as given in the Declaration of Helsinki and approval from the institutional ethical committee was obtained before starting the study.
Statistical analysis
IBM SPSS Statistics version 20.0 (IBM Corp., Armonk, NY, USA) was used for data entry and statistical calculations. The one-way analysis of variance (ANOVA) test was used for statistical comparison. Tukey's honest significant difference post hoc test was used after ANOVA. P < 0.05 was considered statistically significant.
Observation and ResultsIn our study, a total number of 118 patients were registered between December 2017 and July 2021. The age of the patients in our study was between 12 years and 51 years with a mean age of presentation 30.4 ± 10.6. Out of 118 patients, 56.8% were female and 43.2% were male, with a male-to-female ratio of 1:1.3. The majority of patients (68%) in our study were from rural population. The most common diagnosis was chronic otitis media without cholesteatoma (71.2%), followed by chronic otitis media with cholesteatoma (28.8%). There was slight prevalence of left ear (52% left and 48% right) involvement. There were 16% smokers in our study. In our study, tympanoplasty was performed in all patients, CWU mastoidectomies in 37 patients, and CWD mastoidectomies in 16 patients.
The most common ossicular abnormality in this study was erosion of the long process of incus and it was seen in 58 (49%) patients. This was followed by the erosion of stapes seen in 28 (24%) patients and erosion of both malleus and stapes in 19 (16%) patients. The erosion of malleus with intact stapes was observed in only 13 (11%) patients. The ossiculoplasty was performed by autologous incus interposition in 36 patients, partial ossicular prosthesis was used in 35 patients, and total ossicular prosthesis was used in 47 patients.
The postoperative audiological evaluation of the patients in our study was done after 3 months of the surgery. Thereafter, the process was repeated at 6 months, 1 year, and 2 years of the surgery. The PTA AB gap closure to ≤20 dB was taken as successful outcome of the surgery. In our study, of 118 patients, only 110 patients came for the follow-up at the 6 months after the surgery, 98 patients came for the follow-up at the 1 year, and 85 patients came for follow-up at 2 years. The mean audiological gain in the patients having chronic otitis media without cholesteatoma was 19.7 ± 4.2 and in the group of patients having chronic otitis media with cholesteatoma was 17.2 ± 6.7.
The mean audiological gain after the 3 months of the surgery in the group of patients with low-, intermediate-, and high-risk OOPS index was 19.1 ± 4.0, 17.9 ± 4.8, and 15.9 ± 5.3, respectively. The difference between the groups was statistically significant having a P = 0.02. On applying post hoc Tukey's honest significant difference test between low-, intermediate-, and high-risk OOPS index groups, the difference between low- and high-risk group was statistically significant with P = 0.005. The mean audiological gain for different categories of OOPS index at 3 months postoperatively is shown in [Table 2].
The major cause of avoiding the surgical procedure advised in the developing countries is the cost of surgery and absence from work and loss of wages. The other main problem in the developing countries like India is the loss to follow-up. In our study, we tried to enroll only those patients who were willing for long-term follow-up and others were excluded. Still, there were some patients who did not returned for follow-up as they considered it to be insignificant after complete recovery. At the 6 months of follow-up, only 110 patients were reviewed. The audiological results at the 6 months of ossiculoplasty are shown in [Table 3].
The patients having satisfactory progress at 6 months were reviewed after 1 year of surgery and audiological evaluation was done. The total number of patients for review at 1 year of follow-up was 98; others were lost to follow-up. The mean audiological gain in various groups of OOPS index after 1 year of surgery is compared in [Table 4].
In our study, the patients were followed for a maximum duration of 2 years. The mean audiological gain in low-, intermediate-, and high-risk groups was evaluated at this follow-up and their statistical significance was studied. At 2 years, only 85 patients turned up for follow-up. The results at 2 years are compared in [Table 5].
In our study, some of the patients developed complications such as displaced prosthesis (3 patients), delayed graft failure (5 patients), or recurrence of cholesteatoma (4 patients). For the above-mentioned complications, they required subsequent intervention in the form of second look surgery or revision of surgery. The incidence of complications and subsequent revision surgery was significantly higher in the patients having cholesteatoma.
DiscussionThe principle of ossiculoplasty is to reconstruct the middle ear conducting mechanism that is sustainable over the period of time. The objectives of the surgery for chronic otitis media are removal of disease from the middle ear cleft and reconstruction of hearing mechanism. In the developing countries, the cost of surgery and loss of wages for absence from work are major restrains for staged surgical procedure. If the outcome of the surgery can be predicted depending on the pathologic condition of the middle ear, both the cost-effectiveness of the surgery and patient's compliance will improve.
The development of prognostication system for ossiculoplasty will be useful in predicting the hearing results to the patients, for comparison of different surgical procedures and as a tool for assessment of skill acquisition in trainees. There have been various attempts by the researchers to develop preoperative risk stratification index. The Bellucci classification takes into consideration the otorrhea as an indicator of ongoing middle ear infection and the predictor of outcome.[14] The Wullstein classification[15] and Austin classification[16] take into consideration the intraoperative status of ossicular chain and predict the outcome of surgery. The MERI and the SPITE tube factors are based on preoperative, intraoperative, and other factors to stratify risk.[17],[18] These classification systems offer useful information in prognosticating the outcomes.
The OOPS index was devised for prognosticating the short-term hearing outcome of the ossiculoplasty.[13] Subsequently, it was also found to be useful in predicting the long-term hearing outcome.[19] The short-term postoperative audiological result measured after 3 months of surgery in our study showed statistically significant difference between low-, intermediate-, and high-risk OOPS index groups. On applying one-way ANOVA, the P value was P = 0.02. The post hoc Tukey's honest significant difference test showed statistically significant difference between low- and high-risk OOPS index groups with P = 0.005. This observation was in concurrence with the findings of Cox et al.[19] In a recent study, Kotzias et al.[20] compared the prognostic accuracy of OOPS and MERI indices and concluded that MERI was more accurate in prognosticating the successful outcome of ossiculoplasty. This study emphasized more on the status of the ossicles as an indicator of successful surgery. However, in our study, we found that different middle ear pathological factors contribute to the outcome of ossiculoplasty and ossicular chain status is not the main factor. Hence, our observations were not in concurrence with the findings of Kotzias et al.[20] The study conducted by Jung et al.[21] on a large cohort showed that OOPS index was a better predictor of successful surgery than MERI and this study was also in concurrence to our study which proved OOPS to be a predictor of successful ossiculoplasty.
The mean audiological gain in low-, intermediate-, and high-risk group of patients measured at 6 months of the surgery in our study was 19.3 + 4.2, 18.1 + 4.5, and 15.8 + 5.3, respectively. The comparison of results showed a statistically significant difference with P = 0.01. On applying post hoc Tukey's honest significant difference test between the groups, the difference between low- and high-risk OOPS index groups was found to be statistically significant with P = 0.004. This result was in concurrence with the result of Cox et al.[19] The study conducted by Kotzias et al.[20] emphasized more on the ossicular chain status as predictor of outcome and concluded that MERI is a better prognostic index in ossiculoplasty, although they did not mention the material used for ossiculoplasty in their study. The findings of the Kotzias et al.[20] were not in concurrence to our study, which showed that ossicular chain status is not the only factor determining the outcome. The study conducted by Jung et al.[21] concluded that OOPS is a better index for prognosticating the outcome of ossiculoplasty and was in concurrence to our study.
The long-term postoperative audiological result measured after 1 and 2 years of the surgery, as defined by the 1995 American Academy of Otolaryngology–Head and Neck Surgery guidelines in our study, showed a statistically significant difference between low-, intermediate-, and high-risk OOPS index groups. On applying one-way ANOVA for audiological results at 1 year, the P = 0.01. The post hoc Tukey's honest significant difference showed a statistically significant difference between low- and high-risk OOPS index groups with P = 0.003. These findings were in concurrence with the findings of Cox et al.[19] In the study of Kotzias et al.,[20] they found MERI to be more useful and their findings were not in concurrence to that of our present study. The results of the study by Jung et al.[21] was also in concurrence to our study.
In our study, the difference between the mean audiological gain in the group of the patients with low-, intermediate-, and high-risk OOPS index score had a statistically significant difference (P = 0.01) at 2 years of follow-up. On application of the post hoc Tukey's honest significant difference test, the low- and high-risk OOPS index groups showed a statistically significant difference with P = 0.007. This observation in our study was also in concurrence with the findings of Cox et al.[19] and Jung et al.[21] The study conducted by Kotzias et al.[20] had different findings than our study; this may be related to the different cohort of the patients selected and the materials used for ossiculoplasty. In our study, we found that middle ear pathological factors are the most important factor for predicting the outcome of ossiculoplasty.
The present study was prospective in nature with shortcomings such as children were excluded from our study. The loss to follow-up was also a major problem in this study. We evaluated the audiological outcomes of the ossiculoplasty for 2 years postoperatively; more long-term follow-up may help in better prognosticating the outcomes.
ConclusionThe OOPS index takes into consideration the pre- and intraoperative findings of the patients and predicts their audiological outcome. As the outcome of ossiculoplasty is affected by the multiple factors, a better understanding of predictive roles of various factors will significantly improve the results of ossiculoplasty. In this study, it was observed that the OOPS index score had a statistically significant correlation with the audiological outcome. The patients having low-risk OOPS index score had better outcomes than the patients having intermediate- and high-risk OOPS index score. Hence, we conclude that the OOPS index accurately prognosticates both the short-term and long-term outcomes of ossiculoplasty.
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Conflicts of interest
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References
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