ENT Specialist OSSICULOPLASTY

OSSICULOPLASTY

Introduction: Ossiculoplasty is the reconstruction of the middle ear ossicular chain which has been disrupted or destroyed, by the use of interpositioned implants which help in regaining the original mechanics of the ossicular chain to transfer the sound energy to the inner ear. Ossicular abnormalities can range from loss of ossicular continuity due to trauma, congenital,surgical manipulation or middle ear pathology such as cholesteatoma or fixation of the ossicles in cases of otosclerosis or it can be in combination. History: In 1957, the first ossicle reconstruction was done by Hall and Ryztner by means of autograft ossicles. House et al. in 1966 introduced ossicular repair with homograft ossicles by sculpting the ossicles and fixing properly. In the late 1950s and the 1960s, biocompatible material, such as Polyethylene tubing, Teflon, and Proplast, were used. Wehrs in 1972 used homograft ossicles for reconstruction of ossicular chain. Later in 1989, he designed hydroxyapatite prosthesis in order to reduce preparation time and obviate concern about disease transmission. He concluded that this prosthesis performed well and fulfilled their function of emulating the homograft ossicles.
Aetiology of Ossicular abnormalities:
  1. Cholesteatoma.
  2. Chronic suppurative otitis media.
  3. Trauma.
  4. Congenital malformations.
Classification of Ossiculoplasty:  Austin in 1971 Classified ossicular defects into:
  • Group A having malleus and stapes intact and erosion of long process of incus being the most common defect.
  • Group B with only malleus and absent stapes.
  • Group C with only stapes and absent malleus.
  • Group D with absent malleus and stapes suprastructure.

Kartush added three more classes to Austin classifications for intact ossicular chain but with ossicular fixation:

  • Group E for ossicular head fixation with intact ossicles.
  • Group F for stapes fixation with presence of all ossicles.

Candidates for Ossiculoplasty:

  1. The clinical presentation of patients who would benefit from ossiculoplasty is quite variable.
  2. The goal of ossicular chain reconstruction is better-hearing, most typically for conversational speech.
  3. The aim of ossiculoplasty is not only to close the air-bone gap but to improve the patient’s overall hearing (improve the air conduction score).
  4. A patient’s perceived hearing improvement is best when the hearing level of the poorer-hearing ear is raised to a level close to that of the better-hearing ear.
  5. Small improvements in hearing are more likely to be appreciated by patients with bilateral hearing loss.
  6. In most cases, the worst ear is selected for surgery, but unless the surgery can restore symmetrical or nearly symmetrical hearing, or convert the operated ear into the better ear, the patient is unlikely to experience a reduction in disability.
  7. The conductive hearing loss may be the result of ossicular erosion or fixation from chronic ear disease, blunt or penetrating trauma, or congenital or neoplastic causes.
  8. It may also be associated with inner ear causes. These inner ear causes include superior semicircular canal dehiscence and an enlarged vestibular aqueduct. In these conditions ossiculoplasty is not useful.

Contraindications for Ossiculoplasty:

  1. Active infection in the ear is the only true contraindication.
  2. Relative contraindications include persistent middle ear mucosal disease, sensorineural hearing loss and repeated unsuccessful use of the same or similar prosthesis.

Prerequisites for Ossiculoplasty:

  1. The presence of normal or minimally hypertrophied middle ear mucosa.
  2. Patent eustachian tube orifice.
  3. Mobile stapes footplate.

Materials used for Ossiculoplasty:

  1. The materials used in ossiculoplasty can be autografts or homografts or of synthetic materials.
  2. Autografts:a) It includes refashioned ossicles, cortical bone and cartilage.

    b) They have the advantage low extrusion rates.

    c) The most commonly used autograft material has been the incus body, which is often reshaped to fit between the manubrium of the malleus and the stapes capitulum.

    d) Autograft materials are not always available, or as in patients with cholesteatoma, an ossicle may have microscopic squamous epithelium infiltration that precludes such use.

    e) Autografts have several disadvantages it includes

      • Lack of availability in chronically diseased ears.
      • Prolonged operative time to obtain and shape the material.
      • Resorption and/or loss of rigidity (especially with cartilage).
      • Possible fixation to the walls of the middle ear.
      • Osteitis may exist within the ossicles, and the risk of residual cholesteatoma may be increased in patients with cholesteatoma.
  3. The Grafts processed from cadavers like cadaver ossicles, cadaver knee cartilage can be called as homografts.
  4. Because of the disadvantages of autograft materials and the potential risk of infection from homograft implants, alloplastic materials are the most commonly used materials for ossicular reconstruction.
ENT Specialist Screenshot 2020 11 20 Ear final book document
5. The synthetic prosthesis fulfilling criteria of biocompatibility gives most advantageous hearing results..
  1. Alloplastic materials include:
    • Metals (titanium and gold)
    • Plastics (Plastipore, Proplast, Polyethylenes, Polytetrafluroethylene, or Teflon).
    • Biomaterials (Ceramics and Hydroxyapatite).
  2. Bioinert materials like are titanium are well tolerated as extrusion rates are within acceptable limits.
ENT Specialist Screenshot 2020 11 20 Ear final book document
c) Alloplastic materials are losing popularity despite early encouraging results due to high rates of extrusion and absence of long-term results except for hydroxyapatite becoming more successful as regards to functional hearing. d) Bone cement (Glass Isonomer ):

    ➣ It has good biocompatibility, often used in dental procedures.

    ➣ It is very easy to use and much more economical than the prosthesis.

    ➣ Bone cement is prepared and shaped easily. After it becomes firm it doesn’t get affected by any fluids like blood.

    ➣ Bone cements are substances produced by an acid-base reaction. This means that formulated powder is mixed with a liquid to generate a mixture that hardens through a reaction.

    ➣ Polymaleinate glass ionomer cement is a commercially available bone cement that can be used to reconstruct a discontinuity between the ossicular chain – most commonly the incus and the stapes.

ENT Specialist Screenshot 2020 11 20 Ear final book document
Techniques: 
  1. Earlier most of the surgeons adopted the loose interposition technique.  The transposition technique is placing ossicle or the device between handle of malleus and stapes footplate or the superstructure.
  2. Cartilage ossiculoplasty used for atelectatic retraction problems.
  3. Incus interposition ossiculoplasty uses body and short process of incus more often and if need body and long process can also be used.
  4. Dr Prof Robert Vincent of France in 2004 introduced Malleus Relocation technique in ossiculoplasty. He achieved 10 db gain in his total ossicular replacement prosthesis with Silastic banding.
Complications:
  1. Fracture of the stapes superstructure.
  2. Dislocation of the stapes.
  3. Tear of the annular ligament with a perilymphatic fistula.
  4. Severe or total sensorineural hearing loss
  5. Stapedial footplate fracture with incus-stapes prosthesis.
  6. Vertigo.
  7. Erosion or extrusion of prosthesis.

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