How Well Does Intraoperative Audiologic Monitoring Predict Hearing Outcome During Middle Fossa Vestibular Schwannoma Resection?

OBJECTIVE: To evaluate the association between signal changes during intraoperative audiologic monitoring and postoperative audiometric outcome in patients undergoing vestibular schwannoma (VS) resection via middle cranial fossa (MCF) approach. STUDY DESIGN: Retrospective chart review. SETTING: Academic tertiary referral center. PATIENTS: One hundred twenty-six consecutive patients (mean age 48.6 yrs, range 16-67; mean tumor size 9.9 mm, range 1.8-18.9 mm) who underwent MCF VS resection. INTERVENTIONS: Intraoperative audiologic monitoring using auditory brainstem response (ABR) and direct cochlear nerve action potential (CNAP). MAIN OUTCOME MEASURES: Intraoperative ABR wave V and CNAP N1 amplitudes and postoperative pure-tone average (PTA) and word recognition score (WRS). RESULTS: On ABR, absent wave V amplitude was associated with an 81.1% increase and 82.3% decrease in postoperative PTA and WRS, respectively. On CNAP, decreased or absent N1 amplitude was associated with 47.3 and 100% increase, respectively, in postoperative PTA, and 45.3% and 100% decrease, respectively, in postoperative WRS. Receiver-operating curve analysis showed that ABR combined with CNAP using a Cueva electrode achieved the highest diagnostic accuracy in predicting postoperative hearing decline when measured by WRS class (sensitivity 83.3%, specificity 100%), and performed better compared with each modality alone. CONCLUSION: Intraoperative ABR wave V and CNAP amplitude changes are associated with changes in postoperative hearing, and dual modality monitoring was more diagnostic of postoperative hearing decline compared with each modality alone during MCF VS resection. Overall, intraoperative ABR and CNAP were more specific than sensitive for postoperative hearing decline.

Technical Refinements and Outcomes of the Modified Anterior Septal Transplant.

IMPORTANCE: Severe anterior septal deviation and resultant nasal obstruction represent a difficult surgical task to correct. The goal of surgery is to straighten the anterior dorsal and caudal struts, while maintaining nasal tip and midvault support. This study presents a novel extracorporeal septoplasty technique to straighten the crooked anterior septum. OBJECTIVE: To describe the novel anterior septal transplant technique, which consists of complete resection of the caudal septum and reconstruction with extended spreader grafts and a columellar strut, without a separate caudal septal replacement graft. DESIGN, SETTING, AND PARTICIPANTS: This study was a retrospective case series at a tertiary academic referral center. Participants were sequential adult patients undergoing anterior septal transplant from January 1, 2008, to December 31, 2015. MAIN OUTCOMES AND MEASURES: Patient-reported nasal obstruction using Nasal Obstruction Symptom Evaluation (NOSE) scores and objective photographic analysis. Nasal tip deviation, projection, and rotation were measured. Preoperative and postoperative outcomes were compared. Complications are reported. RESULTS: Seventy-one patients (mean age, 46 years [age range, 16-72 years]; 48 [67.6%] female and 23 [32.4%] male) were included in the case series. Postoperative NOSE scores (mean [SD], 24.00 [24.58]) were significantly better than preoperative NOSE scores (mean [SD], 72.25 [14.55]) (P < .001). A separate cohort of 32 patients (mean age, 42 years [age range, 13-72 years]; 23 [71.9%] female and 9 [28.1%] male) had photographs available for analysis. In the frontal view, nasal deviation improved from a mean (SD) of 2.9 (2.0) degrees before surgery to a mean (SD) of 1.4 (1.7) degrees after surgery (P = .004). In the base view, the deviation was corrected from a mean (SD) of 4.9 (2.8) degrees to a mean (SD) of 1.7 (1.2) degrees (P < .001). Tip rotation and projection were unchanged after surgery. Four patients had mild dorsal irregularities after surgery. CONCLUSIONS AND RELEVANCE: Anterior septal transplant by the described technique is a safe and effective treatment option for severe anterior septal deviation. LEVEL OF EVIDENCE: 4.

Isoketals form cytotoxic phosphatidylethanolamine adducts in cells.

Levuglandins and their stereo- and regio-isomers (termed isolevuglandins or isoketals) are gamma-ketoaldehydes (IsoK) that rapidly react with lysines to form stable protein adducts. IsoK protein adduct levels increase in several pathological conditions including cardiovascular disease. IsoKs can induce ion channel dysfunction and cell death, potentially by adducting to cellular proteins. However, IsoKs also adduct to phosphatidylethanolamine (PE) in vitro, and whether PE adducts form in cells or contribute to the effects of IsoKs is unknown. When radiolabeled IsoK was added to HEK293 cells, 40% of the radiolabel extracted into the chloroform lower phase suggesting the possible formation of PE adducts. We therefore developed methods to measure IsoK-PE adducts in cells. IsoK-PE was quantified by LC/MS/MS after hydrolysis to IsoK-ethanolamine by Streptomyces chromofuscus phospholipase D. In HEK293 and human umbilical vein endothelial cells (HUVEC), IsoK dose-dependently increased PE adduct concentrations to a greater extent than protein adduct. To test the biological significance of IsoK-PE formation, we treated HUVEC with IsoK-PE. IsoK-PE dose dependently induced cytotoxicity (LC(50) 2.2 muM). These results indicate that cellular PE is a significant target of IsoKs, and that formation of PE adducts may mediate some of the biological effects of IsoKs relevant to disease.