In vitro evaluation of a novel oxygen-generating biomaterial for chronic rhinosinusitis therapy.

BACKGROUND: Hypoxia due to closure at the ostiomeatal complex is widely considered one of the major pathogenic mechanisms leading to chronic inflammation in chronic rhinosinusitis (CRS). The objective of this study was to develop and characterize an oxygen-generating biomaterial (OGB) as an innovative treatment strategy for CRS. METHODS: An OGB was fabricated by coating hydrophobic beeswax (BW, 15mg or 30mg) on the surface of calcium peroxide - catalase complex (CPO-CA, 30mg) and characterized using scanning electron microscopy (SEM). In vitro releases of both oxygen and hydrogen peroxide (H2 O2 ) were spectrophotometrically quantified, and cytotoxicity in human sinonasal epithelial cells (HSNECs) was evaluated. The influence of OGB on transepithelial Cl- secretion was also determined by pharmacologically manipulating HSNECs, cultured under hypoxic conditions, in Ussing chambers. RESULTS: Three groups of OGBs: (1) CPO only; (2) CPO coated with CA and BW (1:1 ratio, CPO-CA(1)-BW(1)); and (3) CPO coated with CA and BW (1:0.5 ratio, CPO-CA(1)-BW(0.5) were analyzed for accumulated oxygen release over 7 days: highest release (mmol/mg) was observed in CPO-CA(1)-BW(1) = 0.11 ± 0.003, followed by CPO-CA(1)-BW(0.5) = 0.08 ± 0.010, and CPO = 0.05 ± 0.004 (p < 0.0001). H2 O2 production (mM) was significantly higher in CPO (1.87 ± 0.50) compared to CPO-CA (1)-BW(1) (0.00 ± 0.00) (p < 0.001) after 24 h. CPO-CA(1)-BW(1) showed significantly reduced cytotoxicity and increased Cl- transport compared to the CPO group. CONCLUSION: A novel OGB (CPO-CA-BW complex) exhibited sustained oxygen release over 7 days without significant cytotoxicity after 24 h in vitro. Preclinical studies evaluating the efficacy of OGB in CRS are warranted, especially for potential therapy in an obstruction-based CRS model.

An Expedited Intracranial Pressure Monitoring Protocol Following Spontaneous CSF Leak Repair.

OBJECTIVE: Spontaneous cerebrospinal fluid (CSF) leaks represent a unique subset of skull base pathology and require distinctive management. Perioperative evaluation and management of intracranial hypertension are essential in preventing further erosion of the skull base and development of recurrent leak. The objective of this study is to evaluate the safety and utility of an expedited protocol for recording and managing intracranial hypertension following endoscopic repair of spontaneous CSF leaks. METHODS: Prospectively collected data was reviewed in patients undergoing endoscopic repair of spontaneous CSF leaks between January 2017 and March 2020. A standard intracranial pressure monitoring protocol was compared to an expedited protocol (EP), and data regarding the two groups was compared for leak location, short-term success of skull base repair, complications, hospital length of stay, and cost-based analysis. RESULTS: Fifty-five patients (standard protocol, n = 28 vs. EP, n = 27) were included in the study. Leak location was similar between cohorts, with the lateral recess being the most common locations in both groups (37.9% vs. 40.6%; P = .90). Postoperative complications (3.6% vs. 7.4%; P = .53) and ventriculoperitoneal shunt rate (32.1% vs. 22.2%; P = .41) were similar among cohorts. There was no difference in lumbar drain complications (0% vs. 7.4%; P = .14) or recurrent leak (7.1% vs. 0%; P = .16). Length of stay was shorter in the EP group [median(interquartile range): 3(1) vs. 2 (1); P < .01]. Total hospital charges were similar between groups (median (USD/$1,000): 83.57 ± 49.58 vs. 83.93 ± 46.11; P = .18). CONCLUSION: An expedited monitoring protocol shortened hospital stay without increased risk of complications. LEVEL OF EVIDENCE: III Laryngoscope, 131:E408-E412, 2021.