What is an endolymphatic shunt?
An endolymphatic shunt is a silicone tube that drains fluid from the inner ear.
Endolymphatic shunt placement is a surgical procedure that involves implanting a small silicone tube in the inner ear to drain excess fluid. This procedure can reverse damage to the ear due to fluid buildup. This eliminates symptoms, such as hearing loss and vertigo, due to collection of fluid (endolymph) in the inner ear. A small amount of bone is removed from around the membranous structure containing fluid in the ear (the endolymphatic sac), which aims to reduce the pressure of the fluid in the sac. The procedure is performed under general anesthesia. The procedure usually takes less than three hours depending on a patient’s condition and comorbidities.
- The patient is usually positioned lying on their back with their head turned to one side and the affected ear pointing up. The neck and head may be immobilized with a pad or brace.
- The surgeon opens the mastoid bone to determine the endolymphatic sac. The mastoid bone is the bone of the skull located just behind the inner ear.
- To gain access to the sac, the doctor removes the bony cover from the sigmoid sinus that is an S-shaped cavity behind the mastoid bone.
- The physician leaves the small, thin, rectangular bone known as Bill’s Island intact. The sigmoid sinus is flattened with gentle pressure.
- The procedure reveals the endolymphatic sac, which the doctor cuts into in order to place a shunt to drain excess fluid. The shunt allows fluid drainage when inner ear pressure is elevated. As the inner ear contains only a few drops of fluid, resorption of the fluid occurs in the mastoid cavity.
- Decompression of the endolymphatic sac involves reducing pressure in this space. It is considered a conservative procedure because of the low rate of hearing loss and the high success rate to control vertigo.
Reason for surgery: Endolymphatic sac decompression is most appropriate for patients who are experiencing dizziness and a feeling that their surroundings or the room is spinning (vertigo attacks) associated with Meniere’s disease and the progression of hearing loss. Meniere’s disease is a condition affecting the inner ear. Its symptoms may include
- Hearing loss that may come and go
- Tinnitus (ringing, buzzing or hissing noises within the ears)
- A feeling that the ears are obstructed or plugged
- Vertigo (a sensation that the environment or oneself is revolving or spinning)
Associated risks: Complications can arise during endolymphatic sac decompression surgery. Complications may include
- Vertigo: In some cases, vertigo attacks may not improve or may even worsen.
- Hearing loss: Sense of hearing may worsen.
- Tinnitus: In rare cases, the patient may still experience more ringing in their ears after surgery than before surgery.
- Facial nerve injury: While facial nerve injury is rare, it can occur after any surgery in the ear.
- Leaking spinal fluid: While this is very rare, it can lead to meningitis (inflammation of the membranes around the brain and spinal cord).
Recovery
- After surgery, the patient may experience pain. They may be placed on painkillers, anti-nausea medications and antibiotics to avoid any complications. The patient may leave the clinic or hospital on the same day of the procedure if deemed stable by the doctor.
- Most patients may return to work the day or two after surgery. Hearing may gradually improve over the course of a few weeks and eventually return to normal.
- The patient may be asked not to board any flights for at least six weeks after the procedure.
- The patient may be advised to not blow their nose for 10 days. Cough and spit out any secretions due to postnasal drip instead of blowing your nose.
Research
- Endolymphatic shunt surgery is considered a low morbidity procedure.
- It has been reported to achieve complete or substantial control of vertigo in 81 percent of patients, with significant improvement in hearing in about 20 percent. Overall, there is a 60 percent chance of curing vertigo, a 20 percent chance that the attacks will remain at the same level of severity and a 20 percent chance that the attacks will get worse. The patient’s vertigo usually improves even if hearing does not.