What Is Exploratory Tympanotomy?
Exploratory tympanotomy is a surgical procedure done in order to approach the middle ear structures for diagnosis purposes. Diagnosis is the key that aids in delivering the proper treatment for any condition. However, sometimes after the clinical workup and radiological follow-up, the clinician will be in doubt about the diagnosis. In such instances, exploratory tympanotomy is carried out, which will provide a unique, safe, and minor surgical procedure that allows for the visualization of the content of the middle ear and thus confirms the other pathological conditions of the ear. This procedure is done when the diagnosis is not confirmed and when there is a need for microscopic visualization, which will help in the diagnosis and enhance the plan for rehabilitation or therapy, or both.
What Are the Indications of Exploratory Tympanotomy?
An exploratory tympanotomy is advised when a middle ear infection is suspected, and there is a need for direct visualization and manipulation of the middle ear. Exploratory tympanotomy is done in patients with conductive and sensorineural hearing loss, which is not very common.
Conductive hearing loss may be post-traumatic, congenital, or acquired. For conductive hearing loss patients, audiometric evaluation and inspection of the ossicular chain’s integrity and mobility are planned. However, the exploratory tympanotomy is not much indicated for sensorineural hearing loss and is usually done when the perilymphatic fistula is suspected. Perilymphatic fistula is when there is a leakage of perilymph from round or oval windows, which are readily accessible for exploratory tympanotomy if surgery is required. The symptoms of perilymphatic fistula are hearing loss and vertigo on exertion.
What Are the Contraindications of Exploratory Tympanotomy?
Exploratory tympanotomy should not be carried out in patients whose external ear canal does not allow passage and manipulation using instruments of the tympanic membrane and the middle ear. Also the other contraindication is when the part of the tympanic membrane annulus that will need to be evaluated is poorly visualized. Prior to the surgery, it should be evaluated if alternatives to the middle ear need to be taken under otomicroscopy. The ear canal should allow the passage of at least a size five aural speculum.
The anatomy of the ear canal may sometimes not allow the passage of the instrument; in such cases, the exploratory tympanotomy is contraindicated. The bony external ear canal may sometimes have a prominent bulge on the anterior wall; this will limit the space available to raise the flap and limit the exposure of the middle ear.
There are various congenital and acquired conditions of the external ear canal that can prevent exploratory tympanotomy. There can be varying degrees of ear canal stenosis which should be kept in mind when operating on patients with craniofacial anomalies or syndromes.
Conditions like exostoses and osteomas can obstruct physically and prevent access to the tympanic membrane, so in these cases, the obstruction needs to be removed prior to exploratory tympanotomy.
What Are the Technical Considerations of Exploratory Tympanotomy?
Exploratory tympanotomy is done under otomicroscopy, typically with an aural speculum. If the external opening of the ear is constricted, an incision might be given in order to expand the aperture of the external ear canal and to accommodate the largest size speculum possible.
Prior to the procedure, the skin of the ear canal is infiltrated with a local anesthetic or vasoconstrictor to achieve local anesthesia as well as vasoconstriction. Otherwise, poor hemostasis will result in reduced visualization throughout the surgical procedure.
The surgeon will decide in advance whether the procedure should be done under IV sedation or monitored anesthesia, or general anesthesia. When the procedure is done under IV sedation, the surgeon will be able to get the patient's feedback on the table itself regarding hearing status, dizziness, or facial nerve stimulation.
How Is Exploratory Tympanotomy Done?
The size of the external ear canal should be sufficient to introduce an aural speculum of at least size five. If the external ear canal opening is small, an incision is made to widen it. In this way, the membranous external auditory canal is expanded. Injection of local anesthetic with vasoconstrictor is given in order to control the bleeding, which is very important for the success of the surgery.
Local anesthetic injections are also administered to potential tissue graft sites in advance, like the tragal areas of the cartilage or postauricular area of the temporalis fascia.
An incision is made in the skin of the canal, and the flap is raised to get access to the structures beneath it and explore the structures in order to find the pathology. Once the procedure is completed, the flap is closed back to its position and is packed with a gelatin sponge soaked in an ototopical antibiotic or any other ear-packing material in order to prevent displacement.
How Is the Outcome of Exploratory Tympanotomy?
Generally, the outcome of the exploratory tympanotomy is good, and care should be taken during the procedure in order to not create any disturbance to the anatomic structures adjacent to it. The tympanic membrane that has been raised is returned to its original anatomical position and stabilized using an ear canal packing.
Conclusion
Exploratory tympanotomy is a diagnostic procedure done in cases where the clinician needs to visualize directly apart from the results of radiological tests and clinical examination. The procedure is a minor surgical procedure done under anesthesia. In case you or your loved ones have any signs and symptoms of any ear disease, consult the specialist to aid in diagnosis and treatment.
