A Study of Use of Autologous Cartilage in Ossicular Reconstruction

Abstract

Ossiculoplasty is one of the commonly done and challenging surgery in otology and has been done using various graft materials. Materials such as autologous cartilage (tragal or conchal) or allograft (homograft) of the same tissue and synthetic materials like polyethylene TORP, ceramic and hydroxyapatite PORP or Titanium prosthesis have been used. But the latter synthetic materials are expensive and have high extrusion rates. Autologous cartilage grafts are selected for Ossiculoplasty as they are easy to harvest at the same site of operation, non-toxic, has less extrusion rate, minimum shrinkage and lateralization. The aim of this study is to know the efficacy of cartilage in ossicular reconstruction and to evaluate hearing outcome. It is a prospective study done on patients attending ENT outpatient department at hospitals attached to J.J.M Medical College, Davanagere. 50 patients were included in the study who underwent ossicular reconstruction either with canal wall up or down mastoidectomy with tympanoplasty. Pre-operative mean ABG was 39.3 db whereas 6 months post-operative mean ABG was 31.6 db with mean ABG improvement of 7.7 db which was statistically significant. Hearing improvement is better in cases where stapes suprastructure was present and also in canal wall up mastoidectomy procedures. This study suggests that cartilage graft (tragal and conchal) is effective in cases of ossicular reconstruction in patients of chronic otitis media and gives good hearing gain. It is also a economical option in developing countries.

Introduction

Surgical management of Chronic Suppurative Otitis Media and cholesteatoma is challenging because of the extensive pathological destruction of middle ear structures including ossicles. In the past, the main consideration in the surgical treatment of otitis media was the control of disease. With the development of tympanoplasty techniques equal attention was given to reconstruction of the hearing mechanism also.

Ossiculoplasty has been done using various graft materials. Materials such as autologous cartilage (tragal or conchal), or allografts (homograft) of the same tissue and synthetic materials like polyethylene TORP, ceramic and hydroxyapatite PORP or Titanium prosthesis have been used. But the latter synthetic materials are expensive and have high extrusion rates. Various ossiculoplasty techniques and prostheses have been studied and reported in the literature. Unfortunately, the multitude of reconstruction techniques attests to the fact that none of the currently available methods are ideal. Conchal and tragal cartilage autograft is used in some of the studies. In this study we used conchal and tragal cartilage for ossicular reconstruction and the objectives of the study were;

1. To know the usefulness of conchal and tragal cartilage in ossicular reconstruction.

2. To study the efficacy of autologous cartilage in ossicular chain reconstruction.

3. To study the type of ossicular damage and hearing improvement in different types of ossiculoplasties.

4. To compare the results of this study with published series of previous authors.

Materials and Methodology

This is a prospective study on patients attending ENT Out Patient Department at hospitals attached to J.J.M Medical College from October 2015–October 2017.

1. Bapuji Hospital, Davangere

2. Chigateri General Hospital, Davangere

All cases with chronic suppurative otitis media were examined in detail, which includes detailed history, ENT examination, Otoscopy and tuning fork tests. This was followed by examination under microscope to study the disease in detail. Pure Tone Audiometry and X-ray mastoids are done in all cases that are planned for surgery.

On admission Informed Written Consent was taken for all patients before surgery.

During the procedure Ossicular condition was noted, and if eroded, accordingly reconstruction (Ossiculoplasty) was done using patient’s own tragal cartilage or conchal cartilage. After surgery all cases were followed for a minimum period of 6 months and all cases were subjected to postoperative pure tone audiometry 6 months after surgery.

Surgical Technique

Cartilage required for ossicular reconstruction is usually harvested, either (1) Tragal cartilage (2) Conchal cartilage is used. An incision is made on the medial aspect of tragus, and cartilage is harvested leaving behind a small strip of cartilage on the dome of tragus. The incision is sutured. The cartilage is trimmed into shape according to the need of ossicular reconstruction. For harvesting conchal cartilage, incision is made superiorly to the eminence of concha after infiltrating the region with lignocaine with adrenaline. The convex most part of cartilage incised approximately 1.5 × 1 cm is harvested. Cartilage graft is placed and ossicular defect reconstructed according to the need and short or long columella ossiculoplasty was done (Figs. 1, 2).

Fig. 1.

Harvesting of tragal cartilage graft

Fig. 2.

Harvesting conchal cartilage

Results

A prospective study was done on 50 patients who have come to ENT opd to J.J.M Medical College. Primarily we have observed the various ossicular defects, surgeries patients underwent and the postoperative PTA ABG values and mean ABG closure values and statistical analysis was done (Table 1).

Table 1.

Improvement after reconstruction of various ossicular defects

Ossicular defect	No. of cases	Preop PTA-ABG	Post op PTA-ABG	Mean PTA-ABG closure
M+S+I−	31	40.6	31.3	9.3
M+S−I−	15	38.6	32.3	5.7
M−S−I−	4	38	34	3.8
M−S+I−	0	0	0	0

In our study, after the ossicular reconstruction,the mean ABG closure is 9.3 db with erosion of incus alone, it is 5.7 db with erosion of incus and stapes and 3.8 db with erosion of malleus,incus and stapes

Discussion

The most common type of ossicular chain erosion encountered in com is necrosis of a long process of the incus because of its anatomical position and course of its blood supply. Various surgical techniques and materials have been used for ossicular chain reconstruction since 1950 but still there is no standardised technique and ideal material that has been accepted worldwide. Three general classes of prosthesis are used today: autograft, homograft and allograft. Autograft prosthesis includes ossicles (Incus, malleus), cartilage (septal, tragal), cortical bone. Advantages of autograft include a very low extrusion rate, no risk of transmitting disease, biocompatibility and no necessity for reconstruction. Displacement, complete absorption, small remnant size and possibility of harbouring microscopic disease have been blamed as potential disadvantages of their use [1] (Table 2).

Table 2.

Hearing improvement in various surgical techniques

Type of surgery	No. of cases	Pre op PTA-ABG	Post op PTA-ABG	Mean PTA-ABG closure
Tympanoplasty	32	35.6	28.3	7.3
ICW mastoidectomy	12	44.9	34.6	9.1
CWD mastoidectomy	6	40.3	35.3	4.3

In our study, out of all the patients who underwent surgery the mean ABG closure of patients who underwent ICW mastoidectomy was 9.1 db and 4.3 db in patients who underwent canal wall down mastoidectomy and 7.3 db in patients who underwent tympanoplasty without mastoidectomy

Homografts are collected from cadavers or healthy person, stored in alcohol and then used for ossiculoplasty [2]. Main disadvantages of these grafts are transmission of prions. For this reason and ready availability of ossicular prosthesis have minimize this practice [3] (Table 3).

Table 3.

Improvement in hearing in response to various procedures at 6 months postoperative period

No. of cases	Pre operative mean PTA-ABG in db	Post operative mean PTA-ABG in db	Mean PTA- ABG closure in db
50	39.3	31.6	7.4

Paired samples test
	Paired differences					t	Df	Sig. (2-tailed)
	Mean	SD	Std. error mean	95% confidence interval of the difference
				Lower	Upper
Pair pre-1 post	8.10600	4.40692	0.62323	6.85357	9.35843	13.006	49	0.000

	Pre-OP PTAABG	Post-OP PTAABG	P value
Mean ± SD	39.34 ± 6.73	31.23 ± 5.49	< 0.0001

In our study of 50 patients who underwent ossicular reconstruction, the 6 months postoperative mean ABG was calculated which came as 31.6 db and mean ABG closure was calculated which was 7.4 db

The P value is calculated using Paired Test. The value is < 0.0001 and is statistically significant

Autologous cartilage graft was one of the first materials used for ossicular reconstruction in 1971 [4]. The advantages include easy availability, biocompatibility, low cost and low extrusion rate. Tragal cartilage, conchal cartilage, septal cartilage, and rib cartilage can all be used [5].

Allograft prostheses are readily available presculptured and made of synthetic materials such as hydroxyapatite [6], plastipore, titanium, glass–ceramics, etc., and are designed to be made biocompatible [7]. Ossicular necrosis, extrusion, displacement and unsatisfactory hearing restoration have been encountered with virtually every type of design [8]. Extrusion of prosthesis has been reported as high as 39%. However can be significantly reduced by placing cartilage or bone between the tympanic membrane and the prosthesis [9].

Austin reported that most common ossicular defect to be erosion of incus with intact malleus and stapes in 29.5% of cases [10] and Kartush found erosion of long process of incus with intact malleus and stapes (Type A) as most common ossicular defect [11].

Shrestha et al. [12] and Mathur et al. reported erosion of incus as most common ossicular defect in their study.

In a study done by Mundada et al. in which ossicular reconstruction done by tragal cartilage, in 115 operated ears, an air–bone gap closure within 10 dB was found in 14.8%, within 15 dB in 34.8%, and within 20 dB in 24.4% of ears.

In a study conducted by Mahanty [13], hearing results were measured by PTA-air–bone–gap (PTA-ABG). Thus they concluded 60% success rate (< 20 db ABG), for ossiculoplasty using cartilage and 56.25% for PORP.

In a study done by Puls.T, 161 cases of conchal cartilage tympanoplasty, when tympanoplasty combined with ossiculoplasty when the stapes was intact, 72% was within 20 dB and when the stapes was absent, and 54.5% was within 20 dB.

In a study done by Chloe et al. [14] on 188 patients with ossicular reconstruction using costochondral cartilage, the postoperative hearing results as determined by the air–bone gap were comparable with those obtained with synthetic alloplastic materials (mean gap, 16.9 dB). However, unlike synthetic materials, no extrusions occurred.

Quranta et al. in their study done on 67 cases of ossiculoplasty with total (TORP) or partial (PORP) chondroprosthesis (costal cartilage), Average air–bone gap significantly improved from 39.2 to 25.4 dB HL. Jha et al. in their comparative study on ossiculoplasty described that failure and extrusion in case of cartilage were 11.5%, in bone 5.9% and in PORP it was 20% [15].

In a study done by Harvey and Lin [16] double cartilage block technique was used and the mean PTA ABG was 23.8 db, and was considered as an effective alternative to prostheses. Karan Sharma, Pratibha Gururani et al. conducted a randomised study on conchal cartilage versus septal cartilage and stated that both are equally efficacious.

In our study most common ossicular defect is erosion of lenticular/long process of incus. This defect (M+S+I−) is similar to studies previously done. Second most common defect is erosion of long process of incus with stapes supra structure.

We used reshaped conchal and tragal cartilage in above mentioned conditions. The results are encouraging. There are no extrusion of autologous cartilage used. The disadvantage is requirement of extra time for harvesting and sculpturing of tragal/conchal cartilage. Post-operative hearing improvement in our tragal/conchal cartilage ossicular reconstruction is seen in all patients with mean ABG closure of 7.4 db which was statistically significant. Hearing improvement is better in cases where stapes is present and also in canal wall up mastoidectomy procedures. These results are comparable to studies previously done and are encouraging.

Although our study results are good, the postoperative follow up period of 6 months is short and requires long term monitoring to know the outcome of the study.

Conclusion

In this study, patients who underwent ossicular reconstruction of ear with cartilage (tragal or conchal) had significant hearing improvement. There were no cases of graft extrusion. There is no risk of transmission of diseases. They are freely available and are easy to carve with no additional economic burden to the patient. There is no ankylosis to surrounding bone which is seen in autologous bony prostheses, hence ossicular reconstruction with cartilage is an efficient method.