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Endolymphatic Sac Surgery
Of the surgical options, his is the most conservative operation with minimal risk to hearing. Unfortunately, control of vertigo occurs in only 50-60% of patients undergoing this operation. There is no way ahead of time to predict who will or will not respond favorably. In some patients, there may be an immediate noticeable improvement in ear pressure and tinnitus, while in others there may be no improvement at all. Since the surgery causes irritation to the ear, dizziness and ear sysmptoms may continue for several months.
Overall, there is a 60% chance of controlling the vertigo attacks, a 20% chance that the attacks will remain the same and a 20% chance that the attacks will be worse. There is a 2% chance of total deafness in the operated ear. Even if hearing is lost, dizziness often still improves.
Because the nerve of facial movement (facial nerve) lies next to the inner ear, there is also a small chance that a temporary weakness of the face could occur for several days or weeks after surgery. This generally recovers completely, but not always.
Few procedures in otologic surgery have been as controversial as endolymphatic sac surgery. Opinions vary from those who conclude the procedure is effective in over 80% of cases to those who believe it is nothing more than a placebo procedure.
Under general anesthesia, an incision is made behind the ear. The mastoid bone is entered and the endolymphatic sac is decompressed, meaning that the bony covering is removed. The sac is then opened and a shunt tube is inserted. The fluid that would normally enter the sac is shunted away from the inner ear and into the cavity created by the surgery where it is reabsorbed.
Exposure of the endolymphatic sac is essentially an extended mastoidectomy. Thin egg-shelled bone is removed from the posterior fossa dura and sigmoid sinus. The endolymphatic sac is distinguished from the dura by color and texture differences (sac is thicker and whiter than surrounding tissue). In endolympahtic sac decompression, the procedure is terminatied following removal of all the bone overlying the sac. Shunt procedures involve incising the lateral leaf of the sac and inseting a drainage tube into the internal lumen of the endolymphatic duct. Shunts can drain into the subarachnoid space or the mastoid space
Typically, endolymphatic sac decompression incurs the same risks as standard mastoidectomy does. Endolymphatic sac shunt carries a higher risk of cerebrospinal fluid complications (leakage, meningitis) when it penetrates into the subarachnoid space.
This procedure takes about 2 hours to perform and patients can either go home the same day or the next day. The ear may protrude slightly shortly after surgery but should return to its original position in the next two to three weeks. Numbness around the ear is common and can last for several months.
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