Strabismus surgery for Medicare-aged patients: more than a decade of insights.

BACKGROUND: The psychosocial and functional impact of strabismus among the elderly is increasingly important as life expectancy increases and factors that enhance the quality of life become more significant. The purpose of this study was to characterize the demographics, presenting complaints, health status, underlying etiology, and outcomes of strabismus surgery in three age cohorts of Medicare-aged patients. METHODS: The medical records of patients at least 65 years of age who underwent strabismus surgery between 2004 and 2015 in a university-based strabismus practice were reviewed retrospectively. RESULTS: A total of 110 patients were identified and divided into three age cohorts for analysis: young-old (age 65-74), middle-old (age 75-84), and old-old (age 85+). At least 75% of patients in all cohorts cited diplopia as their chief complaint (P = 0.87). There was no difference in sex distribution, type of deviation, underlying etiology, or preoperative American Society of Anesthesiologists physical status classification scores between the cohorts (P = 0.68, P = 0.53, P = 0.71, P = 0.93, resp.). By the 6- to 8-week postoperative visit, 63% of all patients reported complete resolution of their presenting chief complaint, 23% reported some improvement, and 11% reported no improvement, with no difference between the cohorts (P = 0.12). CONCLUSIONS: Given the functional and psychosocial impact of strabismus in the elderly, this study lends support to consideration of surgery as a viable option to successfully treat strabismus among the oldest age cohorts.

Human mesenchymal stem cell spheroids in fibrin hydrogels exhibit improved cell survival and potential for bone healing.

Mesenchymal stem cells (MSCs) have great therapeutic potential for the repair of nonhealing bone defects, because of their proliferative capacity, multilineage potential, trophic factor secretion and lack of immunogenicity. However, a major challenge to the translation of cell-based therapies into clinical practice is ensuring their survival and function upon implantation into the defect site. We hypothesize that forming MSCs into more physiologic three-dimensional spheroids, rather than employing dissociated cells from two-dimensional monolayer culture, will enhance their survival when exposed to a harsh microenvironment but maintain their osteogenic potential. MSC spheroids were formed by using the hanging drop method with increasing cell numbers. Compared with larger spheroids, the smallest spheroids, which contained 15,000 cells, exhibited increased metabolic activity, reduced apoptosis and the most uniform distribution of proliferating cells. Spheroids were then entrapped in fibrin gels and cultured in serum-free medium and 1 % oxygen. Compared with identical numbers of dissociated MSCs in fibrin gels, spheroids exhibited significantly reduced apoptosis and secreted up to 100-fold more vascular endothelial growth factor. Moreover, fibrin gels containing spheroids and those containing an equivalent number of dissociated cells exhibited similar expression levels of early and late markers of osteogenic differentiation. Thus, MSC spheroids exhibit greater resistance to apoptosis and enhanced proangiogenic potential while maintaining similar osteogenic potential to dissociated MSCs entrapped in a clinically relevant biomaterial, supporting the use of MSC spheroids in cell-based approaches to bone repair.

Performance analysis of new-generation vitreous cutters.

BACKGROUND: Despite their clinical advantages, smaller-diameter vitrectomy systems pose significant challenges in vitreous removal. The percentage of time the vitreous cutter port is open while cutting (duty cycle) is one of the primary factors that affect flow. Herein, we examine the effect of duty cycle on the flow performance of new-generation cutters relative to current instrumentation. METHODS: Performance of 25-gauge (ga) and 20-ga new-generation spring-return pneumatic cutters (n = 24 and n = 28 respectively) was analyzed relative to current-generation cutters, across their specified cut-speed range under clinical vacuum pressures of 500 mmHg (25-ga) and 200 mmHg (20-ga). A precision balance measured mass of water or porcine vitreous removed from a vial by a cutter; this was recorded in real-time and converted to flow rates. Frame-by-frame analysis of high-speed video was used to determine duty cycle. Data was analyzed using linear regression and the t-test. RESULTS: Compared with the current-generation, the new-generation cutters exhibit increasingly greater water flow rates at higher cut speeds (P < 0.001). Vitreous flow rates of the new-generation cutters are relatively constant as cut speed increases, and are significantly greater than those of the current-generation cutters at cut speeds of 1500 cuts per minute (CPM) or higher (P < 0.001). The new-generation 25-ga cutter exhibits greater vitreous flow rates at higher cut speeds than the current-generation 20-ga cutter: at 2000 and 2500 CPM, the new 25-ga cutter has 1.45 and 11.88 times the vitreous flow rate of the current 20-ga cutter (P < 0.001) respectively. Duty cycles of the new-generation cutters are significantly higher than those of the current-generation at all cut speeds (P < 0.001). CONCLUSIONS: Although a number of factors influence flow, the high and relatively constant vitreous flow rates of the new-generation cutters are most likely due to their maintenance of high duty cycle as cut speed increases. The findings illustrate that in optimizing duty cycle, the vitreous flow efficiency of smaller-diameter cutters can match or exceed that of larger diameter cutters.