Epithelial membrane protein 2 (EMP2): A systematic review of its implications in pathogenesis.

OBJECTIVES: Epithelial membrane protein 2 (EMP2) is a cell surface protein composed of approximately 160 amino acids and encoded by the growth arrest-specific 3 (GAS3)/peripheral myelin protein 22 kDa (PMP22) gene family. Although EMP2 expression has been investigated in several diseases, much remains unknown regarding its mechanism of action and the extent of its role in pathogenesis. Our aim was to perform a systematic review on the involvement of EMP2 in disease processes and the current usage of anti-EMP2 therapies. METHODS: A Boolean search of the English-language medical literature was performed. PubMed, Scopus, Cochrane, and Web of Science were used to identify relevant citations. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: 52 studies met the inclusion criteria for qualitative analysis. Of those, 28 (53.8%) were human-only studies, 11 (21.2%) were animal-only studies, and 13 (25%) studies included both human and animal models. Furthermore, 34 (65.4%) studies focused on EMP2's role in neoplasms, while the remaining 18 (34.6%) articles evaluated its role in other pathologies. CONCLUSION: Overall, the evidence suggests the mechanisms of action of EMP2 are context dependent. Promising results have been produced by utilizing EMP2 as a biomarker and therapeutic target. More studies are warranted to better understand the mechanism and comprehend the role of EMP2 in the pathogenesis of diseases.

Postoperative Pneumolabyrinth Following the Middle Cranial Fossa Approach for Superior Semicircular Canal Dehiscence Repair, 2014-2020.

OBJECTIVE: The present study investigates risk factors and clinical outcomes of postoperative pneumolabyrinth following the middle cranial fossa approach for superior semicircular canal dehiscence repair, a complication that has not been documented previously. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary/quaternary care referral center. METHODS: We conducted a retrospective review of 332 middle cranial fossa procedures from 2014 to 2020 at a tertiary/quaternary care institution. Upon identifying pneumolabyrinth cases from postoperative computed tomography temporal bone scans, we conducted multivariable logistic regression analysis to explore demographic and clinical factors that were independently linked to this complication. We also compared the rates of postoperative symptoms among patients with different grades of pneumolabyrinth. RESULTS: We identified 41 (12.3%) pneumolabyrinth cases. Patients with older age, higher preoperative pure tone average, and frank dehiscence were at higher risk for pneumolabyrinth. Furthermore, patients with pneumolabyrinth reported significantly higher rates of postoperative dizziness and exhibited significantly greater pure tone average and air-bone gap postoperatively as compared with patients without pneumolabyrinth. Finally, higher-grade pneumolabyrinth was associated with increased rates of postoperative hearing loss, and grade III pneumolabyrinth was associated with higher rates of postoperative tinnitus vs grade I and II cases. CONCLUSION: Pneumolabyrinth following the middle cranial fossa approach was associated with poor clinical outcomes, including dizziness and auditory impairment. Old age, high preoperative pure tone average, and frank dehiscence were risk factors for this complication. The highlighted parameters may be important to note when considering this approach as a treatment option and while monitoring postoperative recovery.

A systematic review of stereotactic radiofrequency ablation for hypothalamic hamartomas.

BACKGROUND: The seizure activity associated with hypothalamic hamartomas (HHs) is refractory to medical management and surgical intervention is often required. Stereotactic Radiofrequency Ablation (SRFA) is a minimally invasive technique offering targeted lesion ablation with a reduced risk of complications. OBJECTIVE: Here, we review the current literature on the use of SRFA for HHs. METHODS: This study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic literature review. A database search of PubMed, Cochrane, Embase, and Web of Science was conducted in July 2020. RESULTS: A total of 12 articles were included in this review, showing outcomes for 185 unique patients. Of these patients, 142 (76.8%) experienced some extent of therapeutic benefit in alleviating seizures following SRFA, with 128 (69.2%) patients achieving complete freedom from seizures. Common transient complications included hyponatremia (52 patients, 28.1%), hyperphagia (48 patients, 25.9%), hyperthermia (47 patients, 25.4%), Horner's syndrome (103 patients, 55.7%), and weight gain (75 patients, 40.5%). CONCLUSIONS: SRFA is a potential therapy for patients with HHs, especially when resection confers significant risk to surrounding structures. Multiple rounds of SRFA treatment may be needed in approximately a quarter of patients to improve gelastic seizure outcomes but may not affect non-gelastic seizures. There is limited data on the use of SRFA for HHs and further case series and clinical trials are needed to establish the use of SRFA for HHs.

Concurrent superior semicircular canal dehiscence and endolymphatic hydrops: A novel case series.

INTRODUCTION: Superior semicircular canal dehiscence (SSCD) is characterized by CT-confirmed bony erosion over the superior semicircular canal, creating vestibular and auditory symptoms. Endolymphatic hydrops (EH) is characterized by an MRI-confirmed excess of endolymph within the scala media that distorts the membranous labyrinth. While there is overlap in symptoms, the two diseases result from different pathophysiologies and require different interventions. PRESENTATION OF CASES: A retrospective chart review was conducted at the University of California, Los Angeles on a database of 270 adult SSCD patients, gathered between March 2011 and February 2020. A review of clinical notes, post-operative findings, and imaging was performed for 16 patients who had both CT-confirmed SSCD and an MRI of the internal auditory canal (IAC). Three cases of concurrent SSCD and EH were identified. Medical and surgical history, symptom progression pre- and post-operatively, and treatment outcomes were gathered. One patient's symptoms were resolved via mycophenolate mofetil, another's via hydrochlorothiazide, and the third's via hydrochlorothiazide and bilateral hearing aids. DISCUSSION: Post-surgical persistence of SSCD symptoms that are mutually shared with EH is the strongest indicator that a physician should investigate for concurrent EH. VEMP and audiogram testing in these cases can be misleading and should not be relied on as rule-in or rule-out tests. CONCLUSION: Concurrent SSCD and EH is a rare but treatable entity. Physicians should consider ordering an MRI of the IAC if SSCD patients' symptoms persist or recur after a successful surgery.