Definition and Aim

Ossiculoplasty is the surgical reconstruction of the ossicular chain. The ossicles (malleus, incus, and stapes) are essential for transmitting sound from the tympanic membrane to the labyrinth. Discontinuity or fixation of the ossicular chain, whether congenital or acquired, leads to conductive hearing loss. The aim of ossiculoplasty is to surgically rebuild a sound conducting mechanism.

 

Types of Ossicular Defects and Prostheses

Several prostheses are available to replace the ossicles, depending on the specific ossicular defects. Autograft ossicles can be sculpted to bridge the gap. Homograft-preserved ossicles with or without the tympanic membrane have been used, but they are difficult to procure and carry the risk of disease transmission.

Prerequisites for Ossicular Reconstruction

At the time of ossicular reconstruction in chronic otitis media, it is essential to ensure:

1. The middle ear is healthy and free of mucosal disease and cholesteatoma.
2. The Eustachian tube function is good. Atelectatic middle ears indicate poor Eustachian tube function.

In cases of canal wall-up mastoidectomy performed for cholesteatoma or active mucosal disease, the ossicular reconstruction procedure is delayed for approximately 6 months to ensure the ear is free of disease.

Timing of Ossicular Reconstruction

Primary ossicular reconstruction can be performed in the following scenarios:

1. Traumatic ossicular disruption
2. Fixation of ossicles
3. Canal wall down procedures when there is no mucosal disease or cholesteatoma

Specific Prostheses for Ossicular Defects

1. Incus prosthesis: Used when the incus is missing, but the handle of the malleus and the stapes with superstructure are present and functional.
2. Incus–stapes prosthesis: Used when the incus and stapes superstructure are missing, while the malleus and stapes footplate are functional.
3. Partial ossicular replacement prosthesis (PORP): Used when the malleus and incus are absent, and the stapes is present and mobile. The PORP is placed between the tympanic membrane and the stapes head.
4. Total ossicular replacement prosthesis (TORP): Used when the malleus, incus, and stapes superstructure are absent, and only the stapes footplate is present and mobile.

Classification of ossicular defects:

Austin– Kartush is the most accepted classification which applies to situations without intact incus. It helps to define pre-operative ossicular status to facilitate meaningful analysis of surgical outcomes. Austin proposed it in 1971 with four categories, and later it was modified by Kartush in 1994 with the addition of three further categories.

TABLE: Modifications by Kartush
Group	Ossicular status
O	Intact ossicular chain
E	Ossicular head fixation
F	Stapes fixation

Ideally, ossiculoplasty should be done in a dry, stable well-ventilated middle ear, with an intact tympanic membrane, without any middle ear infection or cholesteatoma. Kartush devised a Middle Ear Risk Index (MERI) which helps in the stratification of risk factors by giving a score of 0–16. It gives an idea preoperatively about successful outcome following surgery.

TABLE: Middle Ear Risk Index 2001
Otologic factor	Maximum score
Otorrhoea	3
Perforation	1
Cholesteatoma	2
Ossicular status	4
Middle ear granulation	2
Previous surgery	2
Smoking	2

Different types of prosthesis with different materials can be used to replace ossicles depending on the ossicular defects. Autografts, allografts and homografts can be used to bridge the gap. Low-tension with a short prosthesis results in better sound transmission and low risk of displacement than high-tension with a long prosthesis.

  TABLE: Surgical options to correct specific defects.

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Learning resources.

• Scott-Brown, Textbook of Otorhinolaryngology Head and Neck Surgery.
• Glasscock-Shambaugh, Textbook of  Surgery of the Ear.
• Logan Turner, Textbook of Diseases of The Nose, Throat and Ear Head And Neck Surgery.
• Rob and smith, Textbook of Operative surgery.
• P L Dhingra, Textbook of Diseases of Ear, Nose and Throat.
• Hazarika P, Textbook of Ear Nose Throat And Head Neck Surgery Clinical Practical.
• Mohan Bansal, Textbook of Diseases of Ear, Nose and Throat Head and Neck surgery.
• Anirban Biswas, Textbook of Clinical Audio-vestibulometry.
• W. Arnold, U. Ganzer, Textbook of  Otorhinolaryngology, Head and Neck Surgery.
• Salah Mansour, Textbook of Comprehensive and Clinical Anatomy of the Middle Ear.

Author:

Dr. Rahul Bagla 

MBBS (MAMC, Delhi) MS ENT (UCMS, Delhi)
Fellow Rhinoplasty & Facial Plastic Surgery.
Renowned Teaching Faculty
Mail: msrahulbagla@gmail.com
India

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