Timothy C. Hain, MD. Tinnitus Page Page last modified: June 11, 2014
|Structures of the ear. Most tinnitus is due to damage to the cochlea (#9 above)|
This is a congenital anomaly in which the internal carotid can present as a middle ear mass. If the carotid fails to develop correctly during fetal life, the inferior tympanic artery enlarges to take it's place. It enters the skull through it's own foramen, courses through the medial part of the middle ear, and then rejoins the petrous ICA (Branstetter and Weissman, 2006).
Dehiscent internal carotid.
The ICA may not have a bony covering as it courses through the middle ear.
Stenosed internal carotid
A bruit from a narrowed IC may cause tinnitus.
Some authors claim that branches of the AICA may abut the 8th nerve and cause tinnitus. We find this idea dubious.
Arteriovenous fistulae cause loud noises, synchronous with the pulse, that can often be heard by others with a stethescope, or sometimes by simply putting one's ear next to the person's head. These sorts of fistulae can often be embolized. Extra caution is needed when the fistula is in the posterior circulation (i.e. fed by the vertebral artery), as it is difficult to thread a catheter through these tiny arteries. It is easy to cause a "vertebral dissection", possibly accompanied by a stroke.
It may seem silly to say this, but in our opinion, it is generally not worth taking on a significant risk of having a stroke to attempt to get rid of a noise in one's head with embolization. The US health care system pays interventional radiologists very well to do embolization, and of course, they have some motivation to improve people's lives through their training. Nevertheless, the decision whether to go forward with a dangerous procedure should be made by the patient's treating physician, rather than a radiologist. Decisions about life-threatening procedures should not be made by the radiologist who may be well trained to thread a catheter into a patient's head, but has no long term relationship with the patient, and also generally has had no clinical training in otolaryngology or neurology. We suggest getting a 2nd opinion from a non-radiologist expert before proceeding with embolization for tinnitus. To avoid conflicts of interest, ideally the expert should work for another medical insitution.
|AV fistula associated with pulsitile tinnitus. Courtesy of Dr. Marcello Cherchi.||Dural AV fistula of the transverse sinus associated with pulsatile tinnitus. Courtesy of Dr. Dario Yacovino.|
This subject is discussed on a separate page.