A comparative study of surgical outcomes of ossiculoplasty using biomaterials and autologous implants

Objective: To determine amongst biomaterials (Teflon and Silicon) and autologous materials (autologous incus and cartilage), the one which give the best results of ossiculoplasty, in terms of increase in hearing sensitivity including cost effectiveness. Methods: Study was conducted in Era’s Lucknow Medical College & Hospital, Lucknow, India. Randomized prospective crossover study with eighteen months follow up. 80 patients of Chronic Suppurative Otitis Media (CSOM) were randomly assigned for ossiculoplasty using biomaterials (Teflon and silicon) and autologous materials ( bone and cartilage ). Surgical outcome was compared for all the four types of implant material used, in terms of increase in hearing sensitivity, extrusion rate, cost effectiveness. Pre-operatively all patients had a pure tone audiogram with a four frequency average (0.5/1/2/4 kHz) calculated for both air conduction and bone conduction. Post-operatively a pure tone audiogram using (0.5/1/2/4 kHz) was performed at 18 months follow-up. Results: Mean hearing gain (change in A-B gap) was 20.80±7.08 dB in autologous group and 19.93±7.27 dB in biomaterials. Hearing Success Rate-It indicates, total no. of patients, whose postoperative AB Gap (calculated at 500Hz,1,2,3 KHz) is equal to or less than 20 dB. In the present study the overall hearing success rate at follow up period of 4 months is 78.8%. For autologous implants it is 80% and for biomaterials it is 77.5%. Conclusion: The study concluded that there is no significant difference in improvement in AB gap, extrusion rate of implant and overall success rate between biomaterials (Teflon, silicon) and autologous implants (autologous incus, cartilage). The only significant difference between the two groups was the cost effectiveness. Hence,it is concluded in our study that the biomaterials and autologous implants used in the study have equal overall efficacy. The autologous material requires no extra cost so it can be considered as a preferred choice of implant, in comparison to biomaterial in SAARC countries, where the majority is of poor patients.


Introduction
Chronic Suppurative Otitis Media (CSOM) is a very common disease in the developing countries especially in our country affecting mainly the younger population.Various factors like socioeconomic condition, over-crowding, lack of concern about hygiene, poverty, illiteracy etc. contribute much towards the occurrence of this disease.
The audiological impairment is very distressing to the patients even if recurrent otorrhea ceases.To improve upon the hearing and to check the recurrence, tympanoplasty surgery came into existence.
Ossiculoplasty is defined as the reconstruction of the ossicular chain.The ideal prosthesis for ossicular reconstruction should be biocompatible, stable, safe, easily insertable, and capable of yielding optimal sound transmission.
There is not much literature of comparison among biomaterial implants both nationally as well as internationally.
In the present study, we compared biomaterials (Teflon and Silicon) and autologous materials (autologous incus and cartilage), the one which give the best results of ossiculoplasty, in terms of increase in hearing sensitivity.

Aims and Objectives:
General: To determine amongst biomaterials (Teflon and Silicon) and autologous materials (autologous incus and cartilage), the one which give the best results of ossiculoplasty, in terms of increase in hearing sensitivity.

Specific:
1. To study and compare amongst all patients the outcome of ossiculoplasty, using different implant materials.Procedure: All cases of chronic otitis media with conductive hearing loss, with suspected ossicular chain discontinuity, (after diagnosing by Pure tone audiometry and otomicroscopy), were taken up for surgery.In all cases of ossicular discontinuity, ossiculoplasty was done by randomly selected autologous materials (autologous incus, cartilage) and biomaterial (Teflon, silicon) (Table I).

Figure.-1: Cartilage Slicer(Used for reshaping cartilage and silicon)
All cases were performed using a post aural approach and standard technique of ossiculoplasty by a single surgeon.After the surgery, every patient was followed for next 18 months.
Pre-operatively all patients had a pure tone audiogram calculated for both air conduction and bone conduction.Post-operatively, pure tone audiograms were performed at 1 st , 2 nd , 4 th , 6 th ,12 th and finally at 18 th months followup.
Hearing results were assessed by comparing pre-operative and post-operative pure tone averages as well as closure of the air-bone gap.Extrusion rates and complications were also assessed till 18 months of follow up.
Inclusion criteria: 1. Cases of chronic otitis media Inactive mucosal disease with pure conductive hearingloss.
2. Both males and females in the age group of 10-55 years were included in the study.
2. Chronic suppurative otitis media squamosal disease with or without complications.
3. Patients below 10 years and above 55 years were excluded from the study.In the present study the overall hearing success rate at follow up period of 4 months is 78.8%.(For Bone and cartilage implant it is same as 80%.For silicon it is 80% and for teflon it is 75 %.)
On comparing individually, the implant was extruded in 2 (10%) of bone group and 1 (5%) of cartilage group patients.The prosthesis was extruded in 2 (10%) of both the subgroups,( teflon and silicon).

D) Comparison of Cost of Implant:
The cost of Silicon implant was around 40 INR (manually reshaped from commercially available silicon block), while the mean cost of Teflon implant was 600 INR.
The cost of implant in teflon subgroup was 15 times higher as compared to that in Silicon.
In Autologous Group, no cost was incurred on implant while in biomaterial Group; a mean cost of Rs 320±284.54 was incurred (Table IV) Statistically, there was no significant difference between two groups in terms of hearing gain, hearing success rate and extrusion rate, but the difference of cost between two groups was significant.

Discussion
Chronic suppurative otitis media often ends up in the breach in conductive chain of the middle ear leading to conductive deafness.The breach in conductive chain calls for rehabilitation of patient through prosthesis.Ossiculoplasty is the surgical treatment.It has been over 50 years since the use of implants has been started in the ossiculoplasty 1 .Although, autologous and biomaterial implants, both are in practice, yet it is always of interest to find out innovative use of materials other than those being conventionally used.In present study, silicon implants are being used.Silicon implants have been successfully used in rhinoplasty 2,3 .The prospects of silicon implants in jaw surgery and innovative areas has been proposed as long back as 1963 4 .
Although autologous implants such as Bone and Cartilage are used extensively for ossiculoplasty, the use of biomaterials such as Teflon is also in practice since long.However, use of silicon implants in ossiculoplasty is rarely reported despite their enormous prospects 5 .The present study is an attempt to evaluate the feasibility and comparative efficacy of biomaterials in general and silicon implants in particular.
A host of biomaterials have been used including vinyl-acryl, polyethylene 6 , PTFE/ Teflon 7 , Stainless steel 8 , Proplast,Plastipore 9 , Aluminium oxide ceramic, Ceravital 10 , Hydroxyapatite 11,12 , Bioglass 13 , Carbon 14 and have shown to be comparable results in terms of change in-hearing status.The acceptability and extrusion rates in these materials were ranged from as low as 1.3% to 30% 15,16 .In the present study, the overall extrusion rate is 8.7% and both autografts and biomaterials behave equally well in ossiculoplasty 17,18 .Biomaterials need to be reserved for cases in which these two are in short supply.
In the present study, the results obtained for silicon prosthesis were comparable to, not only the other biomaterial i.e.Teflon but they were also comparable to autologous implants.The success rate for silicon prosthesis group was 80% which was equivalent to biomaterials in too whereas as compared to Teflon group it was still better by 5%.

Conclusion
In our study, there is no statistically significant difference as far as improvement in AB gap, extrusion rate of implants and overall success rate between biomaterials (teflon, silicon) and autologous materials (bone, cartilage) are concerned.The only significant difference between the two groups was the cost effectiveness.The autologous material requires no extra cost so it can be considered as a preferred choice of implant, in comparison to biomaterial in our setup, where the majority is of poor patients.The role of biomaterial is only recommended for use, in places where the autologous implant could

Figure.- 2
Figure.-2 Silicon Partial ossicular replacement prosthesis X 6 Silicon has been used which is not a new implant material but yet not tried in the middle ear.It showed promising results in terms of acceptability, hearing improvement, patient satisfaction and the results were comparable to other autologous materials.It is a very promising material which can be reshaped exactly like a cartilage with almost equally good results.