Degree of sigmoid sinus compression and the symptom relief using magnetic resonance angiography in venous pulsating tinnitus.

Objectives: To show that mechanical compression of sigmoid sinus is effective for treatment of pulsatile tinnitus caused by sigmoid sinus enlargement, and to evaluate the relationship between the compression degree of sigmoid sinus and the tinnitus symptom relief using magnetic resonance angiography.

Methods: Medical records of twenty-four patients who were diagnosed with venous tinnitus caused by sigmoid sinus enlargement and underwent mechanical compression of sigmoid sinus were reviewed between April 2009 and May 2013. All these patients received computed tomography and magnetic resonance venography study before undergoing surgery and were followed for at least 4 months.

Results: Twenty-three patients felt relief from tinnitus three months after the surgery, and the cross-sectional area of the sigmoid sinus on the tinnitus side was compressed approximately by half (46%-69%) after the surgery. There were 4 patients whose tinnitus suddenly disappeared while lying on the operating table before operation, which may be a result of the patient's emotional tension or postural changes from standing. One of the four patients felt no relief from tinnitus after the surgery, with the cross-sectional area of the sigmoid sinus only compressed by 30%. And two patients of them had a recurrence of tinnitus about 6 months after the surgery. Seven patients had sigmoid sinus diverticula, and tinnitus would not disappear merely by eliminating the diverticulum until by compressing the sigmoid sinus to certain degree. There were 3 minor complications, including aural fullness, head fullness and hyperacusis. The preoperative low frequency conductive and sensorineural hearing loss of 7 subjects subsided.

Conclusion: Mechanical compression of sigmoid sinus is an effective treatment for pulsatile tinnitus caused by sigmoid sinus enlargement, even if it might be accompanied by sigmoid sinus diverticulum. A compression degree of sigmoid sinus about 54% is adequate for the relief of tinnitus symptom. Cases in which patients' tinnitus suddenly disappeared before the surgery might be excluded to improve the efficacy of surgery.