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Liu et al

759

Table 6. (continued)

Postoperative Audiogram Change (n)

Cases with Complications

Source

Symptom (n)

Etiology (n)

Wang 27 (2015)

Stable (postoperative audiograms done for only 9 patients)

‘‘A few patients’’

Persistent periauricular numbness, ear fullness, or collapse of the retroauricular area; recurrent faint tinnitus of persistent rustling (1)

Santa Maria 28 (2013)

Stable

None None None None None None

Zhao 33 (2013) b Xue 30 (2012) Hou 34 (2011) Meng 32 (2010) b Otto 5 (2007)

NA

Stable (2), NA (1)

Improved ipsilateral LFHL

Stable

Stable (2), improved (1)

Total

23 of 95

Abbreviations: ICA, internal carotid artery; ICP, intracranial pressure; JBDi, jugular bulb diverticulum; LFHL, low-frequency hearing loss; MRV, magnetic reso nance venography; NA, not available; PT, pulsatile tinnitus; SS, sigmoid sinus. a Postoperative complications for Eisenman et al 4 were obtained from a related study by Raghavan et al. 36 b Non-English language text (Chinese).

The radiologic prevalence of SSWA is reported to be 1%. 16 Among patients with PT, the prevalence of SSWA is 23%. 16 The etiology of SSWA is poorly understood. It is more prevalent among women and is associated with higher body mass index, 35 an epidemiologic pattern similar to idio pathic intracranial hypertension (another cause of PT). 40 A previous review by Wang et al of SSWA-associated PT in the English literature found a similar association of PT with right-sidedness and female sex. 41 We also found similar SSWA resurfacing outcomes, with 91 of 121 patients (75%) experiencing complete PT resolution in our review as compared with 93 of 127 cases (73%) in theirs. We analyzed fewer SSWA resurfacing cases because we were more selective in our inclusion criteria. In addition to SSWA, dehiscence and aberrancy of the jugular bulb and ICA are becoming more recognized vascu lar causes of PT. The prevalence of jugular bulb or ICA dehiscence associated with PT is not reported. However, a retrospective case series identified jugular bulb dehiscence or diverticulum among 33% of patients with a known venous source of PT detected by clinical examination. 17 Dehiscent ICA canal has a reported prevalence of 2% in temporal bone CT scans, as compared with 1% for dehiscent jugular bulb and \ 1% for dehiscent sigmoid sinus. 42 Some of these findings of ICA dehiscence are likely to be inciden tal, as only a fraction of patients with PT ( \ 1% preva lence 1-3 ) are likely to have symptoms attributable to ICA or jugular bulb dehiscence. Our review has weaknesses inherent to systematic review approaches. Our review includes several small case reports, which may overestimate the successful outcomes of resurfa cing surgery due to publication bias. Indeed, we observed a clear split in our included studies, where small studies ( \ 4

patients) reported no complications and large studies ( 4 patients) reported complications. Occurrence of minor com plications, such as persistent periauricular numbness, may be underestimated if smaller case series have higher thresh olds for reporting such complications. A second limitation is the lack of a reliable method for comparing outcomes of partial resolution. The lack of a standardized, validated method for measuring and reporting tinnitus may hide dif ferences associated with techniques and/or resurfacing mate rials that result in improvement but not complete resolution. Finally, the small sample sizes for resurfacing of the carotid artery (5 cases) and jugular bulb (14 cases) limit the strength of conclusions that can be drawn. Heterogeneity of resurfacing techniques, including a case of ICA transloca tion and coverage with absorbable hemostatic materials, 29 further complicates conclusions. Future reviews should pro vide additional clarity as more cases are reported. Our systematic review supports resurfacing techniques as an option for the management of PT associated with sig moid sinus, jugular bulb, and ICA wall anomalies. Resurfacing surgery appears to be effective and well toler ated for most patients with sufficiently bothersome PT and a vascular abnormality demonstrated on preoperative ima ging. Care must be taken to avoid compression of the sig moid, since this may lead to elevated intracranial pressures. Increased intracranial pressure with associated headache and vision changes was the most commonly reported major complication, occurring in 4% of cases without long-term morbidity or mortality. Resurfacing appears to be effective in most cases by providing a sound baffle to prevent acous tic energy from reaching the cochlea. As a result, the sur geon should judiciously avoid compressing or traumatizing the vasculature in question. Such actions are unlikely to