FLEX January 2024

10976817, 2019, 5, Downloaded from https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599818823205 by National Institutes Of Health, Wiley Online Library on [12/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

Liu et al

757

There were no reports of long-term morbidity or mortal ity as a result of resurfacing surgical complications. Major complications requiring pharmacologic or surgical interven tion were observed in 6 cases across 3 studies (4% of cases among all studies, 6% among studies reporting complica tions) and consisted of sigmoid sinus stenosis due to com pression by resurfacing material or otherwise unexplained obstruction (4 cases) 4,14,25 and sigmoid sinus thrombosis ipsilateral to the side of surgery with incomplete occlusion (2 cases). 4 Patients with these major complications most commonly presented with headache and blurred vision with findings of papilledema and increased intracranial pressure ( Table 6 ). One case of nonocclusive sigmoid sinus throm bosis presented with ipsilateral facial swelling. 4 Only about half of patients with postoperative headache (5 of 9 patients) had a major complication of sigmoid sinus thrombosis or compression. Three patients with postoperative headache had normal head CT findings, 4,36 and 1 patient’s headache self-resolved after 1 week. 26 Sigmoid sinus thrombosis was alleviated by anticoagulation in 3 cases. 4,14 Sigmoid sinus compression was alleviated by surgical reintervention with partial decompression in 1 case. 25 The most commonly reported symptoms of complications (major or minor) were headache in 9 resurfacing cases 4,14,25,26 and persistent periauricular numbness in at least 5 cases. 24,27 Rarer complications included intraopera tive disruption of a vascular diverticulum, transient aural fullness, hyperacusis, and collapse of the retroauricular area ( Table 6 ). There were no reports of postoperative infection. Audiometric data or descriptions of changes from pre- to postoperative hearing thresholds were provided in 18 of the 20 included studies ( Table 6 ). One study had audiometric data for only 9 of its 25 resurfacing cases, 27 and another study reported audiometric data for only 2 of its 3 cases. 30 The most common postsurgical hearing results were stable postoperative audiograms with sometimes transient post operative conductive hearing loss. The second-most common postsurgical hearing change was improved hearing thresholds, seen in 8 resurfacing cases across 5 stud ies, 5,25,26,29,34 which usually consisted of improved low frequency sensorineural hearing loss ipsilateral to the side of PT and resurfacing surgery. There were no reports of long-term symptomatic decreases in hearing thresholds after resurfacing cases. One study reported an ‘‘asymptomatic decrease in pure-tone averages of 5 dB’’ in 1 of 3 cases of resurfacing dehiscent high-riding jugular bulb. 6 Discussion To our knowledge, this is the first systematic review of the worldwide literature based on electronic database searches to assess outcomes of resurfacing surgery and related proce dures utilizing a sound baffle to treat PT associated with the sigmoid sinus, jugular bulb, and ICA or nearby arteries. We found promising outcome data, with . 80% of resurfacing cases showing complete or partial postoperative improve ment of PT for all groups of vascular PT etiologies. Symptoms occurred more in females and on the right side.

An association between use of autologous materials (vs arti ficial materials) and improved degree of PT resolution was found for arterial sources resurfacing, based on 5 cases. No association was found between material density and resurfa cing outcomes. The analysis for this association may have been underpowered given that few cases used soft materials (8 cases) as compared with hard materials (132 cases). Major complications occurred in 4% of cases among all included studies and in 6% of cases among studies reporting complications. Major complications consisted of venous sinus thrombosis or compression, presented as symptomatic intracranial hypertension, and were not associated with long-term morbidity or mortality. There were no reports of persistent symptomatic hearing loss or postoperative infection. Audiometric data were not reported for 2 of the 20 included studies 4,33 and were reported for only a subset of patients in another 2 studies. 27,30 We hope that future clini cal series include more consistent audiometric data. The most common audiometric postoperative change was no change, followed by improvement in low-frequency hearing loss ipsilateral to PT. This hearing improvement may be attributable to alleviation of the low-frequency masking effect of vascular PT. 11 This may be similar to the effect of manual compression of the ipsilateral internal jugular vein to simultaneously improve tinnitus and hearing. 39 Regarding partial-resolution outcomes, it is unclear what effect transient postoperative serous otitis media would have on perceived PT. Fluid and edema may enhance the ‘‘baffle’’ effect of the resurfacing, with later resolution resulting in the perception of PT recurrence. It may also increase perceived PT as a result of additional conductive hearing loss. Resolution of postoperative serous otitis media could also explain the normalization of transient post operative conductive hearing loss seen on postoperative audiograms. The manipulation of major vascular structures within the temporal bone is always associated with the risk of precipi tating intracranial vascular complications. The fact that the majority of venous PT occurs on the right is indicative that turbulent and symptomatic blood flow is more likely to occur on the side with dominant vasculature. As a result, any surgical restriction of flow in these cases is more likely to be clinically significant. It is therefore reasonable that the goal of resurfacing should be to reduce the propagation of acoustic energy to the cochlea and not to restrict blood flow within the vessels in question. Preoperative imaging with high-resolution CT is essential to localize a source of the PT and allow targeted surgical intervention. Additional ima ging (including specific vascular studies) may exclude other possible causes and preexisting stenosis and demonstrate the degree of contralateral venous drainage. The absence of a patent transverse-sigmoid system on the other side may fur ther increase the risk of even conservative venous manipulation. Among the 3 groups of vascular etiologies of PT that we investigated, SSWA 35 has been the most widely studied.