A Surgical Approach to the Correction of Pulsatile Tinnitus caused by a Diverticulum

Sarah Cooper Shaina John* Biology Department BA in Biology Arcadia University Arcadia University, 2013 450 S. Easton Road [email protected] Glenside, PA 19038 [email protected]

Abstract: The unwanted noises of tinnitis may affect over 36 million Americans at some time during their lifetime. A rare type of Pulsatile tinnitus, which coincides with one’s heartbeat and has its origin in the presence of a sigmoid sinus diverticulum, may be amenable to surgical treatment via a transmastoid approach. The goal of this relatively new surgical procedure is the reconstruction of the sinus wall and the resolution of the associated sounds.

Tinnitus, often described as ringing in the ears, is an difficulty sleeping, suffer from fatigue and depression, annoying condition that can be expected to affect one complain of memory problems and exhibit anxiety and out of every five people during their lifetime. Though irritability (Tabuchi et al., 2011). not a disease in itself, it can be a symptom of prob- The most common type of tinnitus is called subjective lems with the auditory system. Common forms of or auditory tinnitus. In auditory tinnitus, sounds typi- tinnitus can be triggered or exacerbated by an array of cally have their origin in the auditory nerve and the substances including antibiotics, cancer medications, central auditory system, which may indicate problems diuretics, antidepressants, quinine-based medications with the outer, middle or inner ear. Only the person and high doses of aspirin. Risk factors for the disorder suffering from tinnitus is able to hear these sounds. include repetitive exposure to loud noises, advanced The less common type of tinnitus is objective tinni- age, smoking, being male, and having high blood pres- tus, also known as somatosounds, which originates in sure. The sounds, which may be intermittent or con- structures in and around the ear. The examiner as well tinuous, are frequently reported to diminish a person’s as the tinnitus sufferer can hear somatosounds. The overall quality of life. People with tinnitus may have most common sources of somatosounds are vascular

Figures 1 and 2: “Left sinus wall dehiscence with the air-on-sinus sign. The two images are a few millimeters apart on the same patient.

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19 HAPS EDucator Spring 2013 bruits, involuntary twitches of the muscles of the palate the sigmoid sinus from the mastoid air cell system, a known as palatal myoclonus, a distended Eustachian condition known as dehiscence. Loss of cortical bone tube, or sounds associated with the tempromandibular to the level of the mastoid air cells may appear as an joint. A vascular bruit, from the French word for noise, “air-on-sinus” sign on a CT scan (Eisenman 2013, Fig.1 refers to sounds that are made by blood turbulence as & 2). One of the possible treatments for this condi- blood flows past an obstruction. The hallmark of vas- tion is a surgical procedure known as transmastoid cular bruit is sound that keeps pace with the heartbeat, reconstruction of the sigmoid sinus. The goal of this resulting in a rare condition known as pulsatile tinnitus procedure is to provide a smooth vascular surface for (Otto et al., 2006). the sigmoid sinus and eliminate any audible sounds of Pulsatile tinnitus is associated with the vasculature blood turbulence by flattening out the sigmoid sinus of the head and and may occur in the arte- diverticulum. In order to accomplish this, an incision is rial system when blood encounters a tumor pressing made behind the ear and a flap of skin and subcutane- against a blood vessel or where atherosclerosis is ous tissue is lifted from the region covering the mastoid present in blood vessels of the middle or inner ear. portion of the temporal bone. Once the skin flap is Atherosclerosis typically results in loss of blood vessel securely anchored out of the way, a flap of periosteum elasticity, which may have an affect on the sound blood is raised exposing the mastoid cortex. The sigmoid makes. High blood pressure can also trigger unusual sinus, its adjacent dura mater and the diverticulum are sounds in blood vessels as can blood turbulence result- exposed through careful dissection. The wall of the ing from stenosis of the internal carotid or the sigmoid sinus is reconstructed using either part of the internal jugular . Unusual sounds may also have temporalis muscle and its associated fascia or bone their origin in abnormal connections between wax. Bone wax is beeswax to which a softening agent and in the dura mater known has been added. It can be used to apply pressure to as arteriovenous malformations. bone in order to stop bleeding or, Arteriovenous malformations asso- as in this case, it can function as ciated with tinnitus usually result in a patching material. When a large the production of unilateral sounds. diverticulum has been exposed, In the venous system, bruits most typically a piece of the temporalis commonly originate from venous muscle is used to cover the defec- stenosis, small groups of abnor- tive area of the sigmoid sinus. The mally coiled veins, or elevated temporalis muscle patch is then intracranial blood pressure (Otto et sutured to the adjacent dura with al., 2006). It is possible to distin- just enough tension to flatten out guish whether pulsatile tinnitus is of the diverticulum. Smaller divertic- arterial or venous origin by gently ula can often be patched with just compressing the internal jugular a sheet of bone wax, cut to proper vein. If the tinnitus is of venous size, and placed over the bulging origin, the compression will cause area of the sinus. Care is taken the observed sound to stop. If the during the surgery to conserve the tinnitus is of arterial origin, the normal diameter of the sigmoid compression will make the sound sinus and the sinus is never ligated louder (Gologorsky et al., 2009). or obliterated. When everything has been completed to the satisfaction of the surgeon, For the 25% of people who are severely affected by the repaired section of the sigmoid sinus is covered tinnitus, definitive cures are hard to come by. However, with the periosteal flap, the skin is closed, and a com- reconstructive surgery has recently become an op- pression dressing is applied to the area. Many patients tion for a rare condition known as intramastoid sigmoid whose pulsatile tinnitus is linked to sigmoid sinus diver- sinus diverticulum, a specific type of venous disruption ticulum, and who are treated surgically, report complete that may be associated with pulsatile tinnitus. Individu- resolution of the offending noise (Eisenman 2011, Otto als with this disorder are diagnosed using computed et al., 2006). tomographic angiography, CTA. This type of imaging, in which contrast dye is injected into the blood stream Along with the success that has resulted from surgi- prior to the scan, offers high resolution of both the cal transmastoid reconstruction of the sigmoid sinus in temporal bone and its vascular anatomy. A typical CTA the treatment of pulsatile tinnitus, there are still unan- scan might begin coverage at the level of C6, include swered questions relating to the pathophysiology of the bifurcation of the common carotid artery and extend sigmoid sinus diverticula. The direct cause of a diver- through the Circle of Willis (Otto et al., 2006). ticulum remains unknown as does its sequential natural history and the exact mechanism by which the sound is When a sigmoid sinus diverticulum is present, the asso- generated. The intracranial vascular abnormalities that ciated increase in blood turbulence can cause the loss are related to the diverticulum, and possibly contribute of the thin layer of cortical bone that normally separates to its formation, have not yet been adequately investi- (Continued on next page) 20 HAPS EDucator Spring 2013 M22_MART8156_07_SE_CH22.QXD 11/14/10 12:25 PM Page 594

594 The Cardiovascular System

Figure 22.21 Major Veins of the Head and Neck

Superficial Temporal Inferior sagittal sinus Deep cerebral Great cerebral Maxillary Petrosal sinuses Right transverse sinus Facial

Sigmoid sinus

Occipital

Vertebral

External Internal jugular jugular

Right subclavian Clavicle Right brachiocephalic Axillary a An oblique lateral view of the head and neck Left brachiocephalic showing the major super cial and deep veins First rib Superior vena cava Internal thoracic Superior sagittal sinus (cut)

Roots of superior cerebral

Superficial Veins of the Head and Neck [Figure 22.21] Superficial veins of the head converge to form the temporal, facial, and maxillary veins (Figure 22.21). The temporal and maxillary veins drain into the external . The fa- Middle cerebral cial vein drains into the ; a broad anasto- mosis between the external and internal jugular veins at the Cavernous angle of the provides dual venous drainage of the sinus Pontal face, scalp, and cranium. The descends superficial to the sternocleidomastoid muscle. Posterior to the Petrosal sinuses clavicle, the external jugular empties into the subclavian vein. Internal In healthy individuals, the external jugular vein is easily palpa- jugular ble, and a jugular venous pulse (JVP) can sometimes be seen at Inferior cerebrals the base of the neck.

Inferior Venous Return from the Upper Limb [Figure 22.22] The cerebellars Sigmoid sinus digital veins empty into the superficial and deep palmar veins of the hand, which interconnect to form the palmar ve- nous arches (Figure 22.22). The superficial arch empties into the cephalic vein, which ascends along the radial side of the Straight sinus Transverse sinus forearm, the median antebrachial vein, and the basilic vein, which ascends on the ulnar side. Anterior to the elbow is the Occipital sinus superficial median cubital vein, which interconnects the b cephalic and basilic veins. Venous blood samples are typically An inferior view of the brain showing the major veins. Compare (Continued on next page) with the arterial supply to the brain shown in Figure 22.14a. collected from the median cubital vein.

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21 HAPS EDucator Spring 2013 gated. The precise radiological criteria for assessing Eisenman, David J. 2013. Associate Professor, the amount of dilation of the sinus that is required in or- Vice-Chairman & Residency Program Director, der to make the diagnosis of pulsatile tinnitus have not Department of Otorhinolaryngology-Head & Neck been established. Furthermore, it is not known if an Surgery, University of Maryland School of Medicine. actual diverticulum must be present in order to produce Personal Interview. May 27, 2013. the tinnitus sound or if a wearing away of the cortex of the mastoid portion of the temporal bone is sufficient to Gologorsky, Y, Meyer SA, Post AF, Winn HR, Patel produce the sound on its own (Eisenman 2011). AB, Bederson JB. 2009. Novel surgical treatment Anecdotal reporting from surgeons suggests that a of transverse sigmoid sinus aneurysm presenting disproportionate number of cases of sigmoid sinus di- as pulsatile tinnitus: Technical case report. verticulum and related pulsatile tinnitus involve only the Neurosurgery. 64(2): 393-394. right ear. This suggests that the usual dominance of the right side of the venous drainage pathway from the Otto, Kristen J, Hudgins PA, Abdelsky W, Mattox DE. brain may in some way play a role in the pathogenesis 2006. Sigmoid sinus diverticulum: A new surgical of the diverticulum. Most lesions in the sigmoid sinus approach to the correction of pulsatile tinnitus. are reported to occur immediately downstream from the Otology & Neurotology. 28:48-53. junction of the transverse sinus and the sigmoid sinus, rather than further along in the sigmoid sinus. This Tabuchi, K. K., Nishimura, B. B., Nakamagoe, M. might suggest that the velocity of the blood as it leaves M., Hayashi, K. K., Nakayama, M. M., & Hara, the transverse sinus and hits the wall of the sigmoid si- A.A. 2011. Ototoxicity: Mechanisms of cochlear nus just distal to the curvature, may weaken the wall of impairment and its prevention. Current Medicinal the sigmoid sinus over time, resulting in the formation Chemistry.18(31): 4866-4871. of a diverticulum. There are some associated vascular anomalies that may contribute to this phenomenon. These anomalies include the failure of the contralateral Illustration Credit: transverse sinus to form, the presence of very small Figure 22.21 “Major veins of the Head and Neck” is contralateral sinuses and stenosis of the ipsilateral used with permission to reprint courtesy of Pearson distal transverse sinus. These anomalies could serve Publishing. The illustration is taken from Human Anat- to further increase the blood velocity in an already omy by Martini, Frederic H., Timmons, Michael J., and dominant side of the venous drainage or abnormally in- Tallitsch, Robert B. 7/e. ISBN 0321688155. p. 594. crease it on a nondominant side and thus influence the blood flow pattern. More research will have to be done to determine if these observed vascular anomalies con- tribute to the formation of sigmoid sinus diverticulum Scan Credit: (Eisenman 2011). Figures 1 and 2 showing a left sinus wall dehiscence with the air-on-sinus sign, is reprinted with permission The success of transmastoid reconstructive surgery, of: the relatively few reported complications associated David J. Eisenman, MD with this surgery and the degree of patient postop- Associate Professor erative satisfaction, indicate that this treatment may Vice-Chairman & Residency Program Director continue to be a viable option for those whose pulsatile Department of Otorhinolaryngology-Head & Neck tinnitus has its origin in the presence of a sigmoid sinus Surgery diverticulum. University of Maryland School of Medicine

*The inspiration for this article came from ShainaJohn, a recent graduate Figure 3 showing a relatively small but symptomatic of Arcadia University who suffers from tinnitus. Excerpts from her senior right sigmoid sinus diverticulum shown in a CT in the thesis titled “Pulsatile Tinnitus Caused by a Defective Sigmoid Sinus” are axial plane, is reprinted with permission of: included in this article. David J. Eisenman, MD Associate Professor Literature cited: Vice-Chairman & Residency Program Director Department of Otorhinolaryngology-Head & Neck Eisenman, David J. 2011. Sinus wall reconstruction Surgery for sigmoid sinus diverticulum and dehiscence: University of Maryland School of Medicine A standardized surgical procedure for a range of radiographic findings. Otology & Neurotology. 32:1116 -1119. ■

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