Predictive Factors for Subjective Vertigo Following Cochlear Implantation: A Regional Multicenter Cohort Study of 395 Patients.

INTRODUCTION: Cochlear implantation (CI) is generally accepted as having a low rate of postoperative complications, but between 9.3% and 13% of cases experience vertigo postoperatively. This study aimed to examine patient, surgical, and device factors contributing toward the risk of postoperative vertigo. METHODOLOGY: A retrospective review was conducted of adult patients who underwent cochlear implant in a regional area of New South Wales from 2007 to 2018. A total of 395 cochlear implant cases were included in the final study. RESULTS: The overall incidence of vertigo at 3 months of follow-up was 7.1% (n = 28/395). No difference was identified in this study between rates of postoperative vertigo between device factors, including implant make (Cochlear vs. Med-El), electrode shape (perimodiolar vs. straight), and electrode model. No significant difference was found also for surgical factors such as the number of electrode rings inserted, side of implantation, or surgical approach of tympanic ramp (round window insertion vs. cochleostomy).A higher percentage of patients with preoperative vertigo experienced vertigo postoperatively (18.4%, n = 7/38), compared with the population without preoperative vertigo (6.0%, n = 21/352) ( p = 0.005). Patients with previous mastoid surgery also reported a higher rate of postoperative vertigo (20%, n = 9/45) compared with those who had not had mastoid surgery (5.43%, n = 19/350) ( p = 0.006). The mean age of patients experiencing postoperative vertigo was higher than the population without postoperative symptoms (67 vs. 63). CONCLUSION: This study of a large multicenter population outlines that patient factors are more critical than surgical or device factors when considering risk factors for vertigo post-cochlear implant.

Systematic Review and Meta-Analysis on the Incidence of Level-Specific Cervical Nodal Metastasis in Primary Parotid Malignancies.

OBJECTIVE: In primary parotid gland malignancies, the incidence of level-specific cervical lymph node metastasis in clinically node-positive necks remains unclear. This study aimed to determine the incidence of level-specific cervical node metastasis in clinically node-negative (cN0) and node-positive (cN+) patients who presented with primary parotid malignancies. DATA SOURCES: Electronic databases (MEDLINE, EMBASE, PubMed, Cochrane). REVIEW METHODS: Random-effects meta-analysis was used to calculate pooled estimate incidence of level-specific nodal metastasis for parotid malignancies with 95% confidence intervals (CIs). Subgroup analyses of cN0 and cN+ were performed. RESULTS: Thirteen publications consisting of 818 patients were included. The overall incidence of cervical nodal involvement in all neck dissections was 47% (95% CI, 31%-63%). Among those who were cN+, the incidence of nodal positivity was 89% (95% CI, 75%-98%). Those who were cN0 had an incidence of 32% (95% CI, 14%-53%). In cN+ patients, the incidence of nodal metastasis was high at all levels (level I 33%, level II 73%, level III 48%, level IV 39%, and level V 37%). In cN0 patients, the incidence of nodal metastasis was highest at levels II (28%) and III (11%). CONCLUSION: For primary parotid malignancies, the incidence of occult metastases was 32% compared to 89% in a clinically positive neck. It is recommended that individuals with a primary parotid malignancy requiring elective treatment of the neck have a selective neck dissection which involves levels II to III, with the inclusion of level IV based on clinical judgment. Those undergoing a therapeutic neck dissection should undergo a comprehensive neck dissection (levels I-V).