Middle Ear Surgery (Tympanoplasty)

Tympanoplasty is the name given to a reconstructive surgical procedure performed on the sound-conducting apparatus, more specifically on the eardrum and ossicular chain. The operation from the field of otolaryngology (ear, nose, and throat medicine) serves to improve hearing performance and is usually based on the repair of a tympanic membrane perforation (perforation of the eardrum) or a chain interruption of the ossicles autitus. The ossicles are responsible for the transmission of sound: The eardrum transmits the sound vibrations to the malleus (hammer), from there the vibrations are transmitted via the incus (anvil) and the stapes (stirrup) to a membrane of the so-called oval window to the middle ear, thereby amplifying the sound pressure more than 29-fold. The vibrations reach the cochlea via the membrane of the oval window, which separates the middle ear from the inner ear. This contains the actual hearing organ, the cortical organ. The cochlea consists of two canals that run to the tip of the cochlea. Both canals are separated by the so-called basilar membrane. The upper canal begins at the oval window, the lower at the round window. Along the entire length of the cochlea sit auditory sensory cells that perceive the sound waves, i.e. transmit the electrical excitation of the auditory cells via the auditory nerve to the central nervous system (CNS). The auditory nerve connects the inner ear with the auditory center in the brain. The different variants of tympanoplasty are divided into five types (I-V) according to Wullstein’s classic tympanoplasty classification. Tympanoplasty type II and III are the most frequently performed operations. A detailed characterization of the procedures is given under the topic “The surgical procedures”.

Indications (areas of application)

  • Chronic otitis media with pathological changes of the tympanic membrane.
  • Cholesteatoma (synonym: pearl tumor) – ingrowth of multilayered keratinizing squamous epithelium into the middle ear with subsequent chronic purulent inflammation of the middle ear; chronic otitis media (middle ear inflammation) in cholesteatoma is called “chronic bone suppuration”
  • Perforation of the tympanic membrane – e.g. traumatic genesis (accidental) [see below “Further notes”].
  • Interruptions of the ossicular chain of different types.

Contraindications

  • Acute otitis externa (inflammation of the external ear).
  • Simultaneous tympanoplasty on both ears – there should be at least three months between the two surgeries
  • Lack of inner ear performance
  • Poor post-treatment options, for example, in young children who do not tolerate re-treatment of their ear.
  • Severe otorrhea – leakage of secretions from the ear in inflammation, injury, tumors or other diseases.
  • Deafness of the opposite ear

Before surgery

Before surgery, a detailed medical history discussion should take place, during which the patient is informed about risks and complications. Part of the surgical planning is the determination of blood coagulation values (PTT partial thromboplastin time Quick, platelet count), accordingly, the use of anticoagulant drugs (eg, acetylsalicylic acid/ASS) should be avoided. Furthermore, an audiometry (hearing test) and an X-ray or a computer tomography (CT) should be obtained. Perioperative antibiosis should be considered (preventive antibiotic administration).

Surgical procedures

The prerequisite for tympanoplasty is adequate inner ear function, as without this the success of the procedure is not given. Tympanoplasty becomes necessary when the eardrum or ossicles have been so damaged by traumatic effects or inflammatory processes that complete healing is not possible without reconstructive surgery. The operation is performed either under local or general anesthesia (local anesthesia or general anesthesia), while the patient is in the supine position and the head is tilted and fixed to the contralateral side (to the opposite side). The surgical area, i.e. the area around the ear should be free of hair, or these should be taped away, for example. According to Wullstein, there are five basic types of tympanoplasty, which are described in detail here:

  • Type I – Myringoplasty – The so-called tympanoplasty involves the sole reconstruction of the tympanic membrane with the ossicular chain intact.The defect is reconstructed with endogenous material, e.g. temporalis fascia (fascia of the temporalis muscle – a muscle fascia is a thin layer of tight connective tissue that surrounds a muscle and holds it in position or shape. In addition, the muscle fascia forms the demarcation of individual muscles from each other) or perichondrium (The perichondrium is also tight connective tissue that covers the surface of cartilage tissues) closed.
  • Type II – Ossiculoplasty – This operation is used to restore a functional ossicular chain if it is slightly damaged.Here, the ossicles can be replaced with prostheses or restored to their original position.
  • Type III – For this operation, a defective ossicular chain with defective malleus and incus, and preserved or partially missing stirrup forms the indication. Either a graft is inserted between the tympanic membrane and the stapes or the position of the patient’s remaining incus is changed. There are two variants of tympanoplasty type III: PORP = Stapeserhöhung or Partial Ossicular Chain Rekonstructive Prosthesis; here the stirrup is preserved and the sound transmission runs from the eardrum via the prosthesis or the repositioned anvil to the stirrup; TORP = Total Ossicular Chain Rekonstructive Prosthesis; here only the foot of the stirrup is still present, so that the rest of the stirrup must also be replaced by a prosthesis.
  • Type IV – Sound protection – Here the ossicles are completely defective or missing, so that the sound vibrations are transmitted directly to the oval window.For sound protection, a small artificial timpani is created (the tympanic cavity is the cavity where the ossicles are normally located).
  • Type V – The ossicles are missing and the oval window is closed so that an access to the inner ear must be created.Tympanoplasty type V according to Wullstein is usually no longer performed today and therefore not described in detail. Instead, the oval window is opened and a prosthesis is inserted.

After surgery

After surgery, the surgical area should be protected. Diving as well as traveling by airplane should be avoided at all costs. Follow-up examinations are necessary and should be observed.

Possible complications

  • Deafness
  • Limited ability to dive and fly
  • Facial nerve damage – damage to the facial nerve, which is responsible for the mobility of the facial muscles.
  • Taste changes due to damage to the chorda tympani (taste nerve).
  • Hearing deterioration
  • No hearing improvement
  • Keloid formation on the auricle
  • Post-surgery
  • Ringing in the ears
  • Otorrhea
  • Vertigo
  • Pain
  • Transplant rejection
  • Reperforation (new perforation: 2.4 %)

Other notes

  • If tympanoplasty for tympanic membrane perforation has not resulted in a desired outcome, problems most often occur in the first 3 months after surgery, and in two-thirds of cases in the first month after surgery.In a study of 359 patients, tympanoplasty initially failed in 20 patients (5.6%); reperforation occurred in 8 patients (2.4%).
  • In children with tympanic membrane perforation, age is unlikely to influence treatment success. In a meta-analysis of five studies with more than 100 children aged 6 to 18 years, no influence of age on the success rate of closure of the perforation could be determined.Conclusion: age is thus no reason to delay a tympanoplasty, unless there is contralateral otitis media (middle ear infection on the opposite side) with discharge.