TY - JOUR
T1 - Electrocochleography as a diagnostic and intraoperative adjunct in superior semicircular canal dehiscence syndrome
AU - Adams, Meredith E.
AU - Kileny, Paul R.
AU - Telian, Steven A.
AU - El-Kashlan, Hussam K.
AU - Heidenreich, Katherine D.
AU - Mannarelli, Gregory R.
AU - Arts, H. Alexander
PY - 2011/12/1
Y1 - 2011/12/1
N2 - Objective: To determine the electrocochleographic characteristics of ears with superior semicircular canal dehiscence (SSCD) and to examine its use for intraoperative monitoring in canal occlusion procedures. Study Design: Case series. Seting: Academic medical center. Patients: Thirty-three patients (45 ears) had clinical and computed tomographic evidence of SSCD; 8 patients underwent intraoperative electrocochleography (ECoG) during superior canal occlusion; 9 patients underwent postoperative ECoG after SSCD occlusion. Interventions: Diagnostic, intraoperative, and postoperative extratympanic ECoG; middle fossa or transmastoid occlusion of the superior semicircular canal. Main Outcome Measure: Summating potential (SP) to action potential (AP) ratio, as measured by ECoG, and alterations in SP/AP during canal exposure and occlusion. Results: Using computed tomography as the standard, elevation of SP/AP on ECoG demonstrated 89% sensitivity and 70% specificity for SSCD. The mean SP/AP ratio among ears with SSCD was significantly higher than that among unaffected ears (0.62 versus 0.29, p < 0.0001). During occlusion procedures, SP/AP increased on exposure of the canal lumen (mean change ± standard deviation, 0.48 ± 0.30). After occlusion, SP/AP dropped below the intraoperative baseline in most cases (mean change, -0.23 ± 0.52). All patients experienced symptomatic improvement. All patients who underwent postoperative ECoG 1 to 3 months after SSCD repair maintained SP/AP of 0.4 or lesser. Conclusion: These findings expand the differential diagnosis of abnormal ECoG. In conjunction with clinical findings, ECoG may support a clinical diagnosis of SSCD. Intraoperative ECoG facilitates dehiscence documentation and allows the surgeon to confirm satisfactory canal occlusion.
AB - Objective: To determine the electrocochleographic characteristics of ears with superior semicircular canal dehiscence (SSCD) and to examine its use for intraoperative monitoring in canal occlusion procedures. Study Design: Case series. Seting: Academic medical center. Patients: Thirty-three patients (45 ears) had clinical and computed tomographic evidence of SSCD; 8 patients underwent intraoperative electrocochleography (ECoG) during superior canal occlusion; 9 patients underwent postoperative ECoG after SSCD occlusion. Interventions: Diagnostic, intraoperative, and postoperative extratympanic ECoG; middle fossa or transmastoid occlusion of the superior semicircular canal. Main Outcome Measure: Summating potential (SP) to action potential (AP) ratio, as measured by ECoG, and alterations in SP/AP during canal exposure and occlusion. Results: Using computed tomography as the standard, elevation of SP/AP on ECoG demonstrated 89% sensitivity and 70% specificity for SSCD. The mean SP/AP ratio among ears with SSCD was significantly higher than that among unaffected ears (0.62 versus 0.29, p < 0.0001). During occlusion procedures, SP/AP increased on exposure of the canal lumen (mean change ± standard deviation, 0.48 ± 0.30). After occlusion, SP/AP dropped below the intraoperative baseline in most cases (mean change, -0.23 ± 0.52). All patients experienced symptomatic improvement. All patients who underwent postoperative ECoG 1 to 3 months after SSCD repair maintained SP/AP of 0.4 or lesser. Conclusion: These findings expand the differential diagnosis of abnormal ECoG. In conjunction with clinical findings, ECoG may support a clinical diagnosis of SSCD. Intraoperative ECoG facilitates dehiscence documentation and allows the surgeon to confirm satisfactory canal occlusion.
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U2 - 10.1097/MAO.0b013e3182382a7c
DO - 10.1097/MAO.0b013e3182382a7c
M3 - Article
C2 - 22072263
AN - SCOPUS:81855164595
SN - 1531-7129
VL - 32
SP - 1506
EP - 1512
JO - Otology and Neurotology
JF - Otology and Neurotology
IS - 9
ER -