Ossiculoplasty: A Prospective Study on 50 Patients Using Various Graft Materials

Abstract

With large number of grafts available for ossiculoplasty, choice becomes difficult. An ideal graft should be safe, easily available, cost efficient, with good hearing results, uptake and low extrusion rates. The ear nose and throat surgeon is still facing the indecision over type of graft to be selected. A prospective study was conducted in Department of Otorhinolaryngology, Rajindra Hospital, Patiala (August 2012–2014) on 50 patients 15–60 years, of either sex with ABG > 40 dB. Operative procedure planned and type of graft decided intraoperatively. Autografts included remodelled malleus, remodelled incus and tragal cartilage grafts. Synthetic (Teflon) grafts were PORP and TORP. Graft uptake/failure was noted at 1 and 3 months. PTA done at 3 months postoperatively. Net hearing gain (change in ABG) was calculated for various grafts used and analysed. Mean age was 35.26 ± 13 yrs, male and female 1:1. Most common involved ossicle was incus (100%) followed by stapes (36%) and malleus (34%). Autografts, 23, uptake in 20 (86.95%), failure 3 (13.04%) cases. Synthetic grafts, 27, uptake 18 (66.66%) and failure 9 (33.33%). ‘p’value 0.09 (non significant). Mean hearing gain, autografts 14.47 ± 6.54 dB and synthetic grafts 14.57 ± 13.12 dB. ‘p’ value 0.976 (non significant). No significant difference seen in mean hearing gain and uptake/failure of autografts and synthetic grafts. Autografts being cost effective are preferred choice.

Introduction

Hearing loss in an individual can be of three types conductive, sensorineural or mixed. Conductive hearing loss is due to any condition that interferes with the transmission of sound through the external and middle to the inner ear. In pure conductive hearing loss, there is no damage to the inner ear or the neural pathway. Conductive hearing losses generally are correctable [1].

Ossicular related etiologies of conductive hearing loss can be congenital or acquired and are mainly attributed to either discontinuity or fixation. Chronic otitis media frequently results in disruption of ossicular chain. Bone resorption from cholesteatomas may occur, owing to enzyme production by the expanding epithelial lining. The long process of the incus, stapes crurae, body of incus and manubrium are involved in that order of frequency [2].

Tympanoplasty refers to any operation involving reconstruction of the tympanic membrane and/or the ossicular chain [3]. The first aim of a tympanoplasty is to remove middle ear disease. The second aim is to restore hearing [4]. Once [4] the disease is removed the surgeon can decide on the type of middle ear reconstruction procedure. The ossicular chain can be reconstructed using various prostheses.

The earliest recorded ossiculoplasty was attempted by Matte in 1901 to re-establish a connection between the tympanic membrane and the oval window in the case of missing ossicles. Since then, numerous materials have been used.

Bio compatible materials like Teflon, proplast and polyethylene were used in late 1950s and 1960s but had complications of extrusion, migration, penetration into the inner ear, or significant middle ear reactivity.

Irradiated homograft ossicles and cartilage were first introduced in the 1960s. However since 1986, homograft materials rarely are used because of the risk of disease transmission (e.g., AIDS, Creutzfeldt-Jakob disease).

In the late 1970s, a high-density polyethylene sponge (HDPS) that had nonreactive properties was developed. The original form was a machined-tooled prosthesis (Plasti-Pore). A more versatile anufactured thermal -fused HDPS (Polycel) arrived later.

Bioinert implants are materials that do not release detectable trace substances. The prototype bioinert material is dense aluminum oxide ceramic (Al₂O₃). This material was popular in Germany and Japan in the 1970s. The implant can be fitted to the undersurface of the tympanic membrane without cartilage coverage.

Bioactive implants were introduced in the 1970s. Bioactive implants react favorably with the body’s tissues to promote soft tissue attachment. The attachment is a direct chemical bond to the surface of the material, not merely a mechanical attachment that occurs with bioinert and biocompatible materials. The first of the bioactive implants were bioactive glasses (Bioglass and Ceravital). Hydroxyapatite is another bioactive material which can be placed directly under the tympanic membrane without increased risk of extrusion [5].

With large number of grafts available for ossiculoplasty choice of graft becomes difficult. An ideal graft should be safe, easily available, cost efficient, with good hearing results, uptake and low extrusion rates. Natural autografts like bone and cartilage have shown that results obtained in terms of improvement in hearing are good with low extrusion rate and cost effective. However it is technically challenging procedure requiring long intra operative time for harvesting, fashioning and reconstructing graft. Synthetic grafts like HA/Teflon/Titanium have an advantage of being a technically straightforward procedure, readily available graft, thus reducing the intra operative time and there is no risk of leaving behind any residual disease. However synthetic grafts are expensive.

The ear nose and throat surgeon is still facing the indecision over type of graft to be selected. Hence the present study was undertaken.

Materials and Methods

The present prospective study was conducted in Department of Otorhinolaryngology, Rajindra Hospital, Patiala from August 2012–2014 on 50 patients of either sex in age group 15–60 years with ABG > 40 dB, both from urban and rural population irrespective of socioeconomic status. An informed consent was taken and the patients selected underwent a detailed evaluation based on history, general physical examination as well as complete ear, nose and throat examination. Tuning fork tests, pure tone audiogram and impedence audiometry were done for preoperative assessment and to confirm degree and type of hearing loss. X ray mastoids done. CT scan if required was done. Operative procedure was planned and type of graft to be implanted was decided on basis of ossicular status intraoperatively. Autografts include remodelled malleus bone, remodelled incus bone or tragal cartilage graft. These were harvested from the same individual(autografts) at the time of operation. Synthetic grafts used were polyethylene (Teflon) grafts—PORP and TORP (Fig. 1, Table 1).

Fig. 1.

Synthetic Prosthesis used a PORP b TORP

Table 1.

Showing dimensions of synthetic grafts (PORP, TORP) used

	PORP	TORP
Shaft diameter OD/ID	2.00/1.20 mm	1.00 mm
Functional length	5.00 mm to 2.00 mm	7.00 mm to 3.00 mm
Flange diameter	4.00 mm	3.00 mm

Patients were put on I.V. antibiotics, analgesics and antihistaminics for 48 h and were discharged on 3rd day after changing mastoid dressing on oral antibiotics, analgesics and antihistaminics. Weekly follow up was done. Graft uptake was noted at 1 month and 3 months postoperatively. PTA was repeated 3 months after surgery to assess the hearing and was compared with that of preoperative audiogram. Net hearing gain (change in ABG) was calculated for various grafts used and analysed.

Results

Of 50 patients operated under study the mean age was 35.26 ± 13.028 years with male to female ratio 1:1. 74% were from rural background and 26% were urban.

Both ears were involved in 30% of cases, only right ear in 40% and only left in 30%. Right ear was the most common operated ear in 31 (62%) cases. Most common complaint was hearing loss, 38(76%) cases followed by discharge 26(52%). Pneumatised mastoid was present in 19 (38%), sclerosed air cells were seen in 22 (44%), and diploeic in 9 (18%).

38 (76%) were operated in general anaesthesia and 12 (24%) were operated in local anaesthesia. Antrum was opened in 33(66%) cases. Of 50 cases, cholesteatoma was present in 23 (46%) cases, granulations in 36 (72%) cases.

Most common involved ossicle was incus (100%) followed by stapes in 18 (36%) and malleus in 17 (34%) cases. Incus was involved in all cases. It was completely absent in 25 (50%) cases, absent long process in 18 (36%) and absent lenticular process in 7 (14%) cases Complete absence of malleus was seen in 8 (16%) cases, absent manubrium 9 (18%) and intact ossicle was seen in 33(66%) cases.

Stapes was seen intact in 32 (64%) and absent superstructure in 18 (36%) cases (Fig. 2).

Fig. 2.

Showing ossicular involvement

Autografts (remodelled malleus, remodelled incus and tragal cartilage graft) were used in 23 cases which showed an uptake in 20 (86.95%) and failure in 3 (13.04%). Failure included graft displacement and extrusion. Synthetic grafts (TORP and PORP) were used in 27 cases which showed uptake in 18 (66.66%) cases and graft failure in 9 (33.33%). When compared had ‘p’ value 0.09 which is non-significant (Table 2).

Table 2.

Distribution of study subjects based on graft prognosis

	(N)	Uptake	Failure	‘p’ value	Sig
Autografts	23(100%)	20 (86.95%)	3 (13.04%)	0.09	NS
Synthetic grafts	27(100%)	18 (66.66%)	9 (33.33%).

The remodelled malleus was used in 5 cases which was uptaken in all the 5 cases (100%) with no failures seen. Remoulded incus was used in 11, uptaken in 9 (81.81%) and extruded/displaced in 2 (18.18%) cases. Tragal cartilage graft was used in 7 cases which showed an uptake in 6 (85.71%) and failure in 1 (14.28%). PORP used in 14 cases with uptake in 11 (78.57%) cases and failure in 3 (21.42%) cases. TORP was put in 13 cases with uptake in 7 (53.84%) cases and extrusion in 6 (46.15%) cases. The ‘p’ value of various grafts used when compared was 0.23 which is non-significant (Fig. 3).

Fig. 3.

Distribution of study subjects based on graft prognosis: comparison of individual grafts used

Mean hearing gain (change in ABG) in autografts was 14.47 ± 6.54 dB and synthetic grafts was 14.57 ± 13.12 dB. ‘p’ value was 0.976 which is insignificant (Table 3).

Table 3.

Comparison of hearing gain of autografts and synthetic grafts

Group	Hearing gain in dB (Mean ± SD)	‘p’ value	Sig.
Autografts	14.47 ± 6.54	0.976	NS
Synthetic	14.57 ± 13.12

Individually mean hearing gain in remodelled malleus was 15.00 ± 3.93 dB, remodelled incus 17.66 ± 3.74 dB, tragal cartilage graft 16.50 ± 2.07 dB, PORP 20.40 ± 9.83 dB and TORP 24.14 ± 9.90 dB ‘p’ value was 0.19 which is insignificant (Table 4).

Table 4.

Comparison of hearing gain of individual grafts

Group	Mean ± SD (dB)	‘p’ value	Sig.
Remodelled malleus	15.00 ± 3.93	0.19	NS
Remodelled incus	17.66 ± 3.74
Tragal cartilage graft	16.50 ± 2.07
PORP	20.40 ± 9.83
TORP	24.14 ± 9.90

Discussion

Ossicular discontinuity is a common cause of conductive hearing loss. The ear surgery today aims at reconstruction of hearing after disease eradication with prime importance. A number of materials both natural and synthetic are available for ossiculoplasty. The ideal graft for ossiculoplasty should be readily available, cost effective, having good uptake, non- absorbable, with good hearing results and low extrusion, migration and foreign body reaction. With large number of grafts/prostheses available choice becomes difficult.

In our study age varied from patients in 2nd decade to 6th decade (15–60 years). Mean age was 35.26 ± 13.028 years. Maximum patients operated were in 3rd decade of life and minimum in 6th decade. In a similar study by Chavan et al. [6] the mean age at presentation was approximately 34 years and 3 months, with the patients ranging from 15 to 62 years of age. Chandrashekharayya et al. [7] found maximum number of patients were from 3rd and 4th decade of life.

Males and females were affected equally (50% each) as there is no anatomical difference in the ear structures of males and females and there is no sex predilection for the COM [8].

In our study most of cases seen were from rural (74%) background and from lower middle class. COM has been found to be more prevelant in rural areas [9, 10] and in low socioeconomic status [11–13]. This can be due to over-crowding, lack of concern about hygiene, poverty, illiteracy and beliefs. Poor living conditions, poor access to medical care, inadequate medical treatment, recurrent upper respiratory tract infections and nasal diseases have been recognized as risk factors for COM [7, 12]. Also rural residence and long distance to health facilities are prime risk factors in developing countries causing non healing ear discharge in COM [12, 14]. Shaheen et al. [15] found that statistically significant association of COM with yearly income of guardian, maternal education, bathing habit, ear cleaning habit, pattern of primary medical consultation.

In our study unilateral involvement of ear (70%) was seen more to bilateral involvement (30%). Olowookere et al. [16] found that unilateral involvement of ear was seen more than the bilateral involvement. Abou-Elhamd et al. [17] found that the other ear is normal in 63% and Kumar et al. [18] in 72% cases.

Right ear was involved more than left ear. Right ear was operated in 62% cases and left ear in 38% cases. Rai [19] found right ear involved more than left. In contrast Olowookere et al. [20] and Chavan et al. [6] found left ear to be affected more. No knowledge of anatomical differences in the ear structures of right and left ear has been reported. The involvement of one side to other is due to random selection of cases.

Most common complaint was hearing loss, 38(76%) followed by discharge 26(52%). Conductive hearing loss was due to perforation of tympanic membrane or disruption of ossicles. COM may also lead to cochlear hair cell damage leading to sensorineural or mixed type of hearing loss. In the ear to be operated, pneumatised mastoids were seen in 38% cases. It is important to know mastoid cellularity as it has a significant effect on the outcome of the surgery [6]. The x-ray is 100% sensitive and specific to know the type of mastoid pneumatisation [19]. It is very useful in diagnosing patients with chronic mastoiditis and cholesteatoma [21, 22]. The location of surgically-important structures, in the middle and inner ear, only rarely change in sclerotic temporal bone [23].

76% cases were operated in general anaesthesia and 24% cases were operated in local anaesthesia. All tympanomastoidectomies in our study were done under general anaesthesia as it causes relaxation for a longer time and reduces the intraoperative patient awareness. Although the reported the advantages of local anaesthesia include less bleeding, less nausea vomiting, reduced pain in the immediate postoperative period, early mobilization, cost-effectiveness, and the ability to test hearing restoration or presence of vertigo during surgery. Safety of local anaesthesia is superior to that of general anaesthesia as it avoids intubation and eliminates of the remote possibility of laryngotracheal complications as well as cardiopulmonary complications related to general anaesthetic agents, but has disadvantage of discomfort due to noise of the drill used causing anxiety and bad recall, backache and improper muscle relaxation, claustrophobia and earache. General anaesthesia was preferred to local anaesthesia in tympanoplasty in children and anxious men/women and to patients having sensitivity to local anaesthesia [24, 25].

In our study primary disease was granulations (72%) followed by cholesteatoma (46%). Similar results were seen in studies by Jamro et al [26] and Udaipurwala et al. [27]. However Yorgancılar et al. [28] and Zhu et al. [29] found cholesteatoma as primary disease. Vikram et al. [30] found that cholesteatoma and granulation tissue were potential risk factors in the complicated chronic suppurative otitis media.

Most involved ossicle was incus, involved in 100% cases. Studies have shown similar results [6, 31–34]. The long process of incus was the most susceptible part (36%) This correlates with the precarious blood supply to the long process of incus that result in the incus being the most susceptible ossicle for erosion [6, 33, 35]. In our study stapes was the second most common ossicle to be involved with absent superstructure seen in 36% cases. Malleus was found to be the most resistant ossicle (intact in 66% cases), manubrium being most affected part (18%). Although the malleus was the least affected bone by erosion, its erosions were the most easily observable finding, handle of malleus being the most commonly necrosed [32, 36, 37] (Table 5).

Table 5.

Comparison of ossicular involvement in various studies

	Incus (%)	Malleus (%)	Stapes (%)
Our study	100	34	36
Gaurano and Joharjy [36]	75	40.64	65.62
Albera et al. [38]	78	20	29
Garap and Dubey [39]	89	32	41

In our study total graft uptake was seen in 76% cases with failure (extrusion/displacement) in 24%. No significant difference was found between uptake of synthetic and natural grafts. Graft failure in autografts/natural grafts can be due to refixation, atrophy, revascularisation of marrow spaces and recurrence of disease due to residual micro-disease on ossicles. Autografts can maintain their contour, size, shape, and physical integrity for long periods of time but are subject to resorption by osteitis when there is recurrent middle ear suppuration, similar to that observed in ossicles in COM. Failure of synthetic prostheses made of porous plastic (plastipore, polycel) is due to foreign body giant cell reactions with various degrees of biodegradation of the implants [40]. The longevity of cartilage graft is more than bone grafts [41] but they develop chondromalacia with resulting loss of stiffness and showed a tendency to undergo resorption [40]. Tragal cartilage with its attached perichondrium gives better results, the attached perichondrium flap anchors to the remnant ossicles and thus provides enough nutrition for the survival of the grafts [42].

In the present study mean hearing gain was calculated (change in ABG) at 3 months post operatively. Mean hearing in autografts was 14.47 ± 6.54 dB and synthetic grafts 14.57 ± 13.12 dB. ‘p’ value was 0.976 which is insignificant showing that there is no statistical difference in hearing gain of grafts of natural and synthetic groups. A study Kawatra et al. [43] and Malard et al. [44] showed similar results with improvement in hearing gap (ABG) of autologous grafts similar to Teflon grafts. Chavan et al. [6] also reported that there was no statistical difference found in the use of different types of ossicular implants for ossiculoplasty, i.e. refashioned incus, Teflon PORP, or TORP.

Conclusion

COM is a disease of low socioeconomic status seen mostly in rural than urban population. Males and females are affected equally. Unilateral involvement was seen more than bilateral involvement. Most common complaint was hearing loss with discharge. On radiology majority of patients had sclerosed mastoid. Incus was the first ossicle to be eroded (100%) followed by stapes (36%), malleus being most resistant (34%). The graft uptake and mean hearing gain of autografts (14.47 ± 6.54 dB) when compared to synthetic grafts (14.57 ± 13.12 dB) was found to be statistically insignificant. Hence in our set up with most of population belonging to low socioeconomic status autografts are preferred choice as they have same hearing gain and uptake as synthetic grafts but are cost effective.

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Abbrevations

ABG

Air bone gap

AIDS

Acquired immune deficiency syndrome

COM

Chronic otitis media

CT

Computed tomography

dB

Decibel

HA

Hydroxyapetite

NS

Non significant

PORP

Partial ossicular replacement prosthesis

PTA

Pure tone audiometry

Sig

Significance

TORP

Total ossicular replacement prosthesis

Yrs

Years