Background

Chronic suppurative otitis media (CSOM) or chronic otitis media (COM) is one of the common causes of hearing impairment and disability [1]. CSOM with or without cholesteatoma frequently results in disruption of the auditory ossicular chain [2, 3]. In ossicular discontinuity, the ossicular coupling-led preferential distribution of sound to the oval window is lost, and the cochlear partition pressure between the round and the oval windows, which drives the cochlear traveling wave, is compromised [4]. The auditory ossicles, malleus incus and stapes, are involved in the amplification of sound waves through the generation of a lever mechanism. This lever mechanism is lost with the disruption of the ossicular chain resulting in conductive hearing loss [5,6,7,8]. Conductive hearing loss from ossicular chain abnormalities may result from either discontinuity or fixation of the ossicular chain. In more than 80% of patients, the cause of ossicular damage is chronic suppurative otitis media with or without cholesteatoma [9]. Trauma or congenital malformations account for most of the remaining causes of ossicular damage. In order of frequency, discontinuity most commonly occurs because of an eroded incudostapedial joint, an absent incus, or absent incus and stapes superstructure [2, 3, 10, 11]. Approximately half of the cases have more than one ossicle involved [12, 13]. In up to 55% of conductive hearing loss cases, ossicular discontinuity or fixation was found to be responsible [14]. Austin divided the ossicular damage into four types based on the presence or absence of malleus and stapes suprastructure assuming incus being absent in all cases. Type A (M + , S +), type B (M + , S −), type C (M − , S +), and type D (M − , S −) [15, 16]. The most commonly encountered ossicular defect is type A, followed by types B, C, and D in this order. This was modified by Kartush [16] with the addition of three further categories to include a normal ossicular chain and cases of fixation [17].

The treatment of CSOM has improved from just preventing complications to a focus on the improvement and restoration of hearing with the development of ear microsurgery techniques for chronic suppurative otitis media (CSOM) [1]. Various techniques of tympanoplasty have evolved from time to time, and improvisation is being done based mainly in terms of hearing improvement using ossicular reconstruction (ossiculoplasty) after clearance of disease [18]. Materials used in ossiculoplasty include autografts such as autologous ossicles, cartilage and bone and homologous grafts such as homologous bone and synthetic materials such as polytetrafluoroethylene (Teflon), plastipore, hydroxyapatite, and titanium. The selection of a particular prosthesis must be based on several factors, including compatibility, ease of configuring the prosthesis during surgery, availability, and cost [19, 20]. There still exists a considerable difference in opinions in using either type of graft in terms of the selection of graft material, graft remodeling intra-operatively, extrusion rates, and postoperative hearing outcome [21]. The ideal ossicular prosthesis should be manageable, versatile, biocompatible, and stable over time [22, 23]. Thus, there is a need felt to comprehensively and holistically evaluate the outcome of ossiculoplasty using autograft (cartilage and refashioned incus) and synthetic graft polytetrafluoroethylene (Teflon).

The aim of the present study was to find out the mean air conduction thresholds (ACT) and air–bone gap (ABG) closure across the treatment groups at the end of 3 and 6 months of follow-up using different types of graft materials such as autologous cartilage, autologous refashioned incus, or synthetic grafts like Teflon partial ossicular reconstruction prosthesis (PORP) and total ossicular reconstruction prosthesis TORP.

Methods

Setting of the study

This prospective study was conducted in the Department of ENT & HNS, Government Medical College (GMC), Srinagar, J&K, India. The study was conducted from September 2018 to August 2020 over a period of 2 years.

Population

The population comprised patients attending the ENT Outpatient Department of Otolaryngology SMHS Hospital of GMC Srinagar.

Sample size

The sample size consisted of 60 patients who were admitted to the ENT Department and fulfilled the criteria for sample selection.

Study design

It was a prospective study.

Criteria for sample selection

The following are the inclusion criteria:

  1. a)

    Patients of CSOM (safe and unsafe) with ossicular erosion

  2. b)

    Patients aged 10 years to 50 years

The following are the exclusion criteria:

  1. a)

    Patients of CSOM with complications or seeking revision surgery

  2. b)

    Patients of CSOM with SNHL or mixed loss

  3. c)

    Patients of CSOM with associated comorbidities

Tools and techniques

Sixty patients who satisfied the criteria of selection were taken as a sample of the study. History was taken, and an examination was done as a part of the routine workup. All patients were subjected to complete ENT examination including otoscopy, otoendoscopy, and tuning fork tests (TFT). Investigations like pure tone audiometry (PTA) and high-resolution computed tomography (HRCT) of the temporal bone (if otherwise indicated) were done.

Pure tone audiometry (PTA) (preoperative/post-operative at 3 and 6 months)

Air conduction threshold (ACT) and air–bone gap(ABG) were calculated. Hearing thresholds were calculated at frequencies as per the recommendation of AAO-HNS at 500, 1000, 2000, and 3000 Hz.

Surgery

After explaining the need for the surgery and obtaining written informed consent, the surgical procedure followed: The surgery was performed under general anesthesia except in 17 patients who were operated under local anesthesia. All patients were operated through post-aural approach. Tympanoplasty without mastoidectomy was performed in 23 (38.3%) patients, and tympanoplasty with mastoidectomy was performed in 37 (61.6%) patients as per indication. Out of 37 (61.6%) patients with unsafe CSOM, canal wall up mastoidectomy was performed in 16 (26.6%) patients whereas canal wall down mastoidectomy was performed in 21 (35%) patients. The decision to use any ossiculoplasty material for each patient was taken after examining the extent of disease intraoperatively. Autologous materials preferred were possible. In case autologous materials could not be used due to some factors like non-availability in chronically diseased ears, microscopic squamous infiltration of incus in cholesteatoma ears etc. in these cases prosthetic material TORP or PORP was used. Autologous conchal cartilage was reshaped and was used as short columella (malleus/tympanic membrane-stapes assembly) in 14 (23.3%) patients and long columella (malleus/tympanic membrane-footplate assembly) in 3 (5%) patients. Refashioned incus was used as short columella (malleus/tympanic membrane-stapes assembling) in 12 (20%) patients and long columella (malleus/tympanic membrane-footplate assembling) in 2 (3.3%) patients. Teflon PORP was placed over stapes suprastructure in 14 (23.3%) patients whereas Teflon TORP was placed over the footplate in 15 (25%) patients. Disease was unified by the distribution of safe and unsafe ears equally among the study groups and similar air–bone gap (ABG) preoperatively among the study groups. The surgical procedure was unified by the distribution of the ossiculoplasty without mastoidectomy, canal wall up mastoidectomy, and canal wall down mastoidectomy procedures equally among the study groups.

Patients were followed up postoperatively at 3 and 6 months

At each of these follow-ups, otoscopic/otoendoscopic examination and PTA were done.

  • Pre- and postoperative air conduction threshold (ACT) improvement at 3 and 6 months was recorded.

  • Pre- and postoperative air–bone gap (ABG) closure at 3 and 6 months was recorded.

Statistical evaluation

The recorded data was compiled and entered in a spreadsheet (Microsoft Excel) and then exported to the data editor of SPSS version 20.0 (SPSS Inc., Chicago, IL, USA). Continuous variables were expressed as mean ± SD, and categorical variables were summarized as frequencies and percentages. Graphically, the data was presented by bar and pie diagrams. Paired t-test and repeated measure ANOVA were employed to compare the various parameters before and after surgery. P-value < 0.05 was considered statistically significant. All P-values were two-tailed.

Results

A total of sixty patients were included in the study. The mean age in years was 24.3 ± 6.74. There were 32 (53.3%) female and 28 (46.7%) male patients with a male:female ratio of 1:1.4. All 60 (100%) patients complained of impaired hearing followed by 44 (73.3%) patients with ear discharge (persistent/intermittent), 29 (48.3%) patients with tinnitus, 28 (46.7%) patients with earache, 9 (15%) patients with aural fullness, and 5 (8.3%) patients with vertigo. Among twenty-three patients with safe CSOM, active central perforation with granulations was seen in 10 (16.6%) patients, active central perforation with edematous middle ear mucosa and ear discharge was seen in 9 (15%) patients, and dry central perforation with myringosclerosis was observed in 4 (6.6%) patients. In 37 patients of unsafe CSOM, cholesteatoma without retraction pockets was seen in 21 (35%) patients followed by cholesteatoma with retraction pockets in 16 (26.6%) patients. The left ear was operated on in 39 (65%) patients whereas the right ear was operated on in 21 (35%) patients.

Material used for ossiculoplasty (Table 1)

Table 1 Material used for ossiculoplasty [n = 60]
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In this study, autologous cartilage (conchal) was used in 17 (28.3%) patients, refashioned incus was used in 14 (23.3%) patients, Teflon (PORP) was used in 14 (23.3%) patients, and TORP was used in 15 (25%) patients for ossiculoplasty. Out of 14 patients who had ossiculoplasty with refashioned incus, 12 (20%) patients had malleus/tympanic membrane-stapes assembly and 2 (3.3%) patients had malleus/tympanic membrane-footplate assembly. Teflon PORP was placed over stapes suprastructure in 14 (23.3%) patients whereas TORP was placed over the footplate in 15 (25%) patients.

Postoperative air–bone gap (ABG) at 3 months with different ossiculoplasty materials (Table 2)

Table 2 Postoperative air–bone gap (ABG) at 3 months with different ossiculoplasty materials (n = 60)
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In this study, ABG was calculated as per the American Academy of Otolaryngology and Head and Neck Surgery criteria. Postoperative ABG was first assessed at 3 months. In 17 patients who had ossiculoplasty with autologous conchal cartilage, 9 patients had air–bone gap between 11 and 20 dB followed by 4 patients between 21 and 30 dB and 4 patients > 30 dB at 3 months postoperatively. In 14 patients who had ossiculoplasty with autologous refashioned incus, 7 patients had air–bone gap between 11 and 20 dB followed by 5 patients between 21 and 30 dB and 2 patients > 30 dB at 3 months postoperatively. In 14 patients who had ossiculoplasty with Teflon (PORP), 6 patients had air–bone gap > 30 dB followed by 5 patients between 21 and 30 dB and 3 patients between 11 and 20 dB at 3 months postoperatively. In 17 patients who had ossiculoplasty with Teflon (TORP), 7 patients had air–bone gap > 30 dB followed by 5 patients between 21 and 30 dB and 3 patients between 11 and 20 dB at 3 months postoperatively.

Postoperative air–bone gap (ABG) at 6 months with different ossiculoplasty materials (Table 3)

Table 3 Postoperative air–bone gap (ABG) at 6 months with different ossiculoplasty materials (n = 60)
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In this study, postoperative air–bone gap (ABG) was also assessed at 6 months. In 17 patients who had ossiculoplasty with autologous conchal cartilage, 8 patients had air–bone gap between 11 and 20 dB followed by 6 patients between 21 and 30 dB, 2 patients between 51 and 60 dB, and 1 patient between 31 and 40 dB at 6 months postoperatively. In 14 patients who had ossiculoplasty with refashioned incus, 7 patients had air–bone gap between 11 and 20 dB followed by 5 patients between 21 and 30 dB, 1 patient between 31 and 40 dB, and another 1 patient between 51 and 60 dB at 6 months postoperatively. In 14 patients who had ossiculoplasty with Teflon (PORP), 6 patients had air–bone gap between 21 and 30 dB followed by 3 patients between 31 and 40 dB, 2 patients between 11 and 20, 2 patients between 51 and 60 dB, and 1 patient between 41 and 50 dB at 6 months postoperatively. In 15 patients who had ossiculoplasty with Teflon (TORP), 5 patients had air–bone gap between 21 and 30 dB followed by 4 patients between 31 and 40 dB, 3 patients between 51 and 60 dB, and another 3 patients between 11 and 20 dB at 6 months postoperatively.

Preoperative and postoperative mean air conduction thresholds (ACT) at 3 months and 6 months (Table 4)

Table 4 Preoperative and postoperative air conduction thresholds (ACT). Mean at 3 months and 6 months (n = 60)
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In this study, the mean preoperative and postoperative (3 months and 6 months) air conduction thresholds were compared. In patients where autologous conchal cartilage was used for ossiculoplasty, the preoperative air conduction threshold mean was 41.3 (± SD 6.69), and the postoperative air conduction threshold mean at 3 months was 29.2 (± SD 5.39); at 6 months, it was 21 (± SD 4.66). In patients where autologous refashioned incus was used for ossiculoplasty, the preoperative air conduction threshold mean was 40.4 (± SD 5.43), and the post-operative air conduction threshold mean at 3 months was 28.4 (± SD 6.73); at 6 months, it was 20.8 (± SD 4.33). In patients where Teflon PORP was used for ossiculoplasty, the preoperative air conduction threshold mean was 42.9 (± SD 5.68), and postoperative air conduction threshold mean was 31.4 (± SD 6.86) at 3 months, and at 6 months, it was 34.9 (± SD 6.37). In patients where Teflon TORP was used for ossiculoplasty, the preoperative air conduction threshold mean was 43.1 (± SD 5.40), and the postoperative air conduction mean was 32.5 (± SD 5.91) at 3 months, and at 6 months, it was 36.2 (± SD 5.31). Pre and postoperative air conduction P-values for autologous conchal cartilage, refashioned incus, PORP, and TORP materials used for ossiculoplasty were recorded as 0.003, < 0.001, 0.182, and 0.319, respectively.

Preoperative and postoperative air–bone gap (ABG) mean at 3 months and 6 months (Table 5)

Table 5 Preoperative and postoperative air–bone gap (ABG). Mean at 3 months and 6 months (n = 60)
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In this study, the mean preoperative and postoperative air–bone gap at 3 months and 6 months was compared. In patients where autologous conchal cartilage was used for ossiculoplasty, the preoperative air–bone gap mean was 40.6 (± SD 4.57), and the postoperative air–bone gap mean was 23.7 (± SD 4.48) at 3 months, and at 6 months, it was 20 (± SD 5.28). In patients where autologous refashioned incus was used for ossiculoplasty, the preoperative air–bone gap mean was 39.3(± SD 4.92), and the postoperative air–bone gap mean was 21.9 (± SD 5.61) at 3 months, and at 6 months, it was 19.4 (± SD 5.82). In patients where Teflon PORP was used for ossiculoplasty, the preoperative air–bone gap mean was 43.0 (± SD 4.48), and the postoperative air–bone gap mean was 32.8 (± SD 4.84) at 3 months, and at 6 months, it was 36.3 (± SD 5.56). In patients where Teflon TORP was used for ossiculoplasty, the preoperative air–bone gap mean was 44.5 (± SD 5.56), and the post-operative air–bone gap mean was 33.2 (± SD 5.53) at 3 months, and at 6 months, it was 35.2 (± SD 5.10). Pre- and postoperative air–bone gap P-values for autologous conchal cartilage, refashioned incus, PORP, and TORP used for ossiculoplasty were recorded as < 0.001, < 0.001, 0.227, and 0.114, respectively. Statistically significant difference (P-value < 0.05) was observed in pre- and postoperative ABG (at 3 and 6 months) where autologous conchal cartilage (< 0.001) and refashioned incus (< 0.001) were used for ossiculoplasty (Fig. 1).

Fig. 1
figure 1

Preoperative and postoperative air–bone gap mean at 3 months and 6 months

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Discussion

Reconstruction of the ossicular chain is still a develo** surgical discipline in otolaryngology. The goal in ossiculoplasty is to have a stable and reliable connection between the tympanic membrane and the mobile stapes footplate in order to achieve the best hearing result in addition to achieving a dry ear.

This study was designed to find out the hearing outcome in patients with CSOM using different ossiculoplasty materials. Accordingly, patients were divided into four groups: autologous cartilage group, refashioned incus group, PORP group, and TORP group. In this study, out of 14 patients who had ossiculoplasty with refashioned incus, 12 (20%) patients had malleus/tympanic membrane-stapes assembly and 2 (3.3%) patients had malleus/tympanic membrane-footplate assembly. Teflon PORP was placed over stapes suprastructure in 14 (23.3%) patients whereas TORP was placed over the footplate in 15 (25%) patients. Choudhary et al. [24] included 50 patients in their study out of which 28 patients (56%) underwent autologous reshaped incus ossiculoplasty and 22 patients (44%) underwent ossiculoplasty using PORP. Chaudhary, Anand, and Taperwal [25] distributed 100 of their patients according to the type of reconstruction in which 27% of patients underwent malleus stapes assembly, 17% of patients malleus footplate assembly, 23% of patients short columella, and 15% of patients long columella. Robert et al. [26] included 137 patients in which autologous or homologous sculpted incus interposition was used between intact malleus and stapes suprastructure. In a study by Mahanty et al. [27], refashioned incus was interposed between the handle of malleus and the stapes suprastructure. Hajela et al. [28] placed autograft incus between the manubrium of the malleus and the stapes head. Pathan et al. [29] included 100 patients categorized intraoperatively into two groups of 50 patients where one group underwent ossiculoplasty with tragal cartilage and the other with PORP. Group division and surgical technique used in our study were similar to most of the abovementioned previous studies.

Preoperative ACT was similar in all four groups and was between 41 and 43 dB (Table 4). Postoperatively, the mean air conduction threshold of < 20 dB was obtained with autologous conchal cartilage and refashioned incus but not with the Teflon prosthesis (PORP, TORP). Statistically, a significant difference (P-value < 0.05) was observed in pre- and postoperative air conduction at 3 and 6 months where autologous conchal cartilage (0.003) and refashioned incus (< 0.001) were used for ossiculoplasty. In a study by Kumar et al. [30], preoperative mean air conduction in the autologous incus group was 41.60 ± 8.86 dB. Similarly, preoperative mean air conduction in the titanium prosthesis group was 42.80 ± 9.19 dB. In the autologous incus group, the postoperative mean air conduction was 33.82 ± 8.0 dB. Similarly, in the titanium prosthesis group, the postoperative mean air conduction was 32.97 ± 9.02 dB. In another study by Chavan et al. [31], the mean preoperative ACT was 47.89 dB. In another study by Chauhan et al. [32], the mean preoperative mean air conduction was 35 dB ± 12 dB. The postoperative mean air conduction was 27.4 ± 11.5 dB.

In this study, it was observed that in 29 (48.3%) patients, preoperative air–bone gap was between 41 and 50 dB followed by 17 (28.3%) patients between 31 and 40 dB, 8 (13.3%) patients between 21 and 30 dB, and 6 (10%) patients between 51 and 60 dB. It was found that the preoperative mean air–bone gap in patients who underwent ossiculoplasty using autologous conchal cartilage, autologous refashioned incus, Teflon (PORP), and Teflon TORP was 40.6 ± 4.57, 39.3 ± 4.92, 43.0 ± 4.48, and 44.5 ± 56, respectively. The preoperative ABG was more or less similar in all four groups. In a study by Kotzias et al. [33], the average preoperative PTA-ABG was 34.63 ± 9.94. Cox et al. [32, 34] found that the average preoperative PTA-ABG was 30.6 dB for adults. In a study by Mahanty et al. [27], 28 patients (56%) had air–bone gap between 40 and 50 dB, 13 patients (26%) had air–bone gap between 30 and 40 dB, 6 patients (12%) had air–bone gap between 50 and 60 dB, and 3 patients (6%) had air–bone gap > 60 dB. Pathan et al. [29] found that the preoperative mean air–bone gap was 36.6 dB with a standard deviation of 6.86 in patients using cartilage and 34.77 dB with a standard deviation of 8.46 in patients using PORP.

Postoperatively, 20 (33.3%) patients had an air–bone gap < 20 dB at 6 months. Seven of 14 (50%) patients who underwent ossiculoplasty using autologous refashioned incus had air–bone gap < 20 dB at 6 months. Similarly, at 6 months, air–bone gap < 20 dB was seen in 8/17 (47%) patients, 2/14 (14.4%) patients, and 3/15 (20%) patients who underwent ossiculoplasty using autologous cartilage, Teflon PORP, and Teflon TORP, respectively. The mean preoperative air–bone gap for patients who underwent ossiculoplasty using autologous refashioned incus was 39.3 ± 4.92 which improved to 19.4 ± 5.82 at 6 months. Similarly, the mean preoperative air–bone gap for patients who had ossiculoplasty with autologous conchal cartilage, Teflon PORP, and Teflon TORP was improved to 21.3 ± 5.28, 36.2 ± 5.56, and 35.2 ± 5.10 at 6 months, respectively. The mean ABG gain in autologous refashioned incus was 19.9 ± 0.9 dB, in autologous conchal cartilage 18.6 ± 0.08, in Teflon (PORP) 6.7 ± 1.1, and in Teflon TORP 9.3 ± 0.01. Pre- and postoperative air–bone gap P-values for autologous conchal cartilage, refashioned incus, PORP, and TORP used for ossiculoplasty were < 0.001, < 0.001, 0.227, and 0.114, respectively. Statistically significant difference (P-value < 0.05) was observed in pre- and postoperative ABG where autologous conchal cartilage (< 0.001) and refashioned incus (< 0.001) were used for ossiculoplasty. Sharma et al. [30] found that in group “A,” the postoperative mean air conduction was 33.82 ± 8.0 dB, the mean bone conduction was 9.41 ± 4.03 dB, the and mean air–bone gap was 24.41 ± 5.90 dB. Similarly, in group “B,” the postoperative mean air conduction was 32.97 ± 9.02 dB, the mean bone conduction was 10.48 ± 3.98 dB, and the mean air–bone gap was 22.37 ± 7.59 dB. Ayache et al. [34] found that 36/61 (59%) patients had air–bone gap ≤ 20 dB. In a study by Emir et al. [35], 58.1% of success (ABG ≤ 20 dB) was observed using autologous incus. Kotzias [33] reported 61% of their patients represented an ABG ≤ 20 dB postoperatively. Kumar et al. [30] found a mean preoperative ABG of 32.88 ± 7.08 dB in the autologous incus group, and in the titanium prosthesis group, the mean preoperative ABG was 32.97 ± 7.25 dB. Similarly, in the autologous incus group, the mean postoperative ABG was 24.41 ± 5.90 dB, and in the titanium prosthesis group, the mean postoperative ABG was 22.37 ± 7.59 dB. Pathan et al. [29] concluded that there is a 60% success rate for ossiculoplasty using cartilage and 56.25% for PORP. In a study by Siddappa et al. [36], the preoperative mean ABG was 39.3 dB whereas the 6-month post-operative mean ABG was 31.6 dB with a mean ABG improvement of 7.7 dB. In a study by Quérat et al. [37], the residual mean air–bone gap was 16.8 dB in the cartilage group (gain of 7.6 dB; P = 0.001) and 15.8 dB in the PORP group (gain of 8.5 dB; P = 0.002). The air–bone gap was less than 20 dB in 67.6% of cases in the cartilage group and 70.4% of cases in the PORP group. In a similar study by Lamba et al. [38], the mean hearing gain for autografts was 14.47 ± 6.54 dB, and the mean hearing gain for synthetic grafts was 14.57 ± 13.12 dB.

Overall in this study, postoperatively at 6 months, hearing loss of < 30 dB was seen in 77% of the autologous conchal cartilage group, 86% of the autologous refashioned incus group, 57% of the TORP group, and 53% of the PORP group which indicates that with all the four commonly used options for ossiculoplasty, good amount of hearing can be given to the patients although there is a significant difference between the results. Last but not least, the study was done during COVID times, and there was a loss to follow-up which makes follow-up possible for only up to 6 months. This affected the results which we expected to be better as patients who feel well or improved after surgery do not usually seek follow-up at least in the develo** world.

Conclusion

The hearing outcome of ossiculoplasty varies with the type of ossiculoplasty material used. Most favorable results were obtained with refashioned incus followed by autologous cartilage while least favorable results were obtained with Teflon prosthesis, TORP, or PORP. Ossicular reconstruction be preferably done with autologous cartilage or refashioned incus where possible, but Teflon prosthesis is also a viable option for hearing reconstruction where other more feasible options are not available. Our study however does not support the use of prosthesis over the autologous graft material. We suggest further studies with larger sample size and longer follow-up for ossiculoplasty hearing outcome studies.