EC: Transcanal Labyrinthectomy/Labyrinthotomy
Introduction: Labyrinthectomy, although rarely performed, may be a very effective surgical procedure for patients who have peripheral, poorly controlled, poorly compensated, and debilitating, episodic or chronic, vestibular dysfunction such as patients who have failed comprehensive medical management for Meniere's Disease (diuretics, low sodium diet, vestibular suppressants, steroids, intratympanic dexamethasone, chemical labyrinthectomy with intratympanic gentamicin, vestibular rehabilitation, etc.).
Other conditions associated with poorly compensated vestibular function include, but are not limited to:
- Vestibular neuritis
- Otic capsule trauma (temporal bone fractures, etc.)
The optimal patient usually has useful hearing and vestibular function (as measured by ice water caloric testing) in the opposite ear and severe-to-profound hearing loss in the affected ear.
The physiologic rationale for labyrinthectomy is to promote central vestibular compensation.
Labyrinthectomy may be performed through a transmastoid or transcanal approach. For patients who are unable to undergo a several hour anesthesia required for a transmastoid approach, a transcanal procedure is preferable as it requires approximately 1 hour to perform. In addition to a shorter operative time, transcanal labyrinthectomy is a more direct approach to the vestibular system, has lower morbidity, less chance for inadvertent facial nerve injury, and less of a probability of cerebrospinal fluid leak.
Transcanal labyrinthectomy results vary between 95 and 99% control of vertigo. Success depends on a thorough ablation of the entire vestibular end organ and postoperative central compensation. Negative factors for success include, but are not limited to, increased age, visual disturbances, obesity, sedentary lifestyle, severe arthritis, immobility, or underlying psychiatric disorders.
Preoperative evaluation: Prior to undergoing a transcanal labyrinthectomy, patients should undergo:
- a complete history and physical examination,
- neurologic examination,
- comprehensive audiometric evaluation,
- vestibular testing (ENG), including binaural ice water caloric testing
- CT scans of the temporal bones and an MRI brain scan with and without gadolinium contrast
- Preoperative counseling and informed consent
Labyrinthectomy may be performed through either a transcanal or transmastoid surgical approach.
Surgical technique for the transcanal approach includes:
- Intraoperative facial nerve monitoring (NIM monitor)
- A larger atticotomy flap than is used during stapedectomy
- Exposure of the middle ear by removal of some posterior and posterior superior canal wall
- Separation of the incudostapedial joint
- Sectioning of the stapedial tendon
- Removal of the incus and stapes
- Connection of the oval and round windows (1 mm diamond burr)
- Thorough removal of the saccule, utricle, and ampullae of the superior, lateral and posterior canals
- Complete removal of the 5 vestibular end organs is imperative
- A sinus tympani excavator (whirlybird) and Day hook are useful instruments
- Care must be taken to completely remove the utricle which can collapse upon opening the vestibule
- Identification and sectioning of the singular nerve
- Care to safeguard the facial nerve and gentle dissection in the vestibule to prevent a CSF leak
- Packing of the enlarged vestibule with Gelfoam soaked gentamicin, 40mg/ml
- Ablation of the enlarged vestibule with a fat graft (harvested from the ipsilateral earlobe)
1. Right middle ear exposure
2. R incus removed
3. R stapedial tendon sectioned
4. R stapes removed. RW opened.
5. Oval and round windows joined.
6. Gelfoam with gentamicin placed.
7. Fat graft obliteration of vestibule
- Unsteadiness, nystagmus, vomiting, etc. may occur and needs to be supported postoperatively with IV fluids, etc.
- One to several days of hospitalization may be required depending on degree of vestibular function preoperatively
- Ondansetron, promethazine, diazepam (sparingly) may be required
- Repeat ice water caloric testing (postoperative vestibular symptoms may occur even with 0 response on calorics)
- Vestibular rehabilitation
- Hearing rehabilitation (ipsilateral hearing aid for "good ear", CROS or BiCROS system, Ponto/Baha implant)
- Consideration for cochlear implantation (currently off-label for single-sided deafness but research is being done)
For more information concerning transcanal labyrinthectomy, please contact our Nursing Department at 336-273-9932 during normal business hours.