C. Dai

Surgical experience of intratemporal facial nerve neurofibromas

Abstract Conclusions: The first presentation of intratemporal facial neurofibromas was variable, with facial palsy most common. The tumors often involve two or more segments of facial nerve. Outcomes of the tumors were closely related to nerve integrity, preoperative facial nerve function level, and follow-up period. Objective: The aim of this study was to present surgical experience of 11 cases with intratemporal facial neurofibroma. Methods: Clinical data of the 11 cases with the tumors was retrospectively collected and analyzed. They were followed up for 37.9 ± 1.7 months, range 13–59 months, except for one case that was only followed up for 5 months and was excluded from the analysis of outcomes. Results: Facial palsy was the first presentation in 10 cases, with repetitive facial palsy and vertigo in 1 case; 6 cases (54.5%) were insidious and 5 (45.5%) were sudden in terms of onset. Ear pain around the onset of facial palsy was found in four cases (36.4%). The tumor involved more than one segment in six cases. Among the non-grafted cases one patient with grade V facial nerve function recovered to grade III and another patient with grade VI facial nerve function recovered to grade IV, whereas only one case with grade VI recovered to grade IV among the grafted cases.

Surgical experience of nine cases with intratemporal facial hemangiomas and a brief literature review.

Abstract Conclusions: It was practicable to remove hemangiomas at the labyrinth region and distal internal auditory canal with complete or serviceable hearing preservation by the transmastoid approach. The majority of cases where the nerve integrity was preserved achieved acceptable recovery of facial nerve function during the first few years according to our study. Long-term outcomes of nerve graft were acceptable, while short-term outcomes were unsatisfactory based on the literature. Objective: This study aimed to present our surgical experience of nine intratemporal facial nerve hemangiomas and provide a brief literature review. Methods: Clinical data for the cases were retrospectively analyzed. They were followed up for 5–59 months and related literature was reviewed. Results: All of the hemangiomas were removed by the transmastoid approach, and only three cases developed mild conductive hearing loss. Nerve integrity was preserved for all cases. In all, 66.7% of patients maintained or recovered to grade III or better, and one patient with grade VI recovered to grade V during the average follow-up period of 2 years. In the literature the majority of grafted patients recovered to an acceptable level 5 years later, although recovery was usually poor during the first year.

A Generalized Interval Fuzzy Chance-Constrained Programming Method for Domestic Wastewater Management Under Uncertainty – A Case Study of Kunming, China

In this study, interval mathematical programming (IMP), mλ-measure, and fuzzy chance-constrained programming are incorporated into a general optimization framework, leading to a generalized interval fuzzy chance-constrained programming (GIFCP) method. GIFCP can be used to address not only interval uncertainties in the objective function, variables and left-hand side parameters but also fuzzy uncertainties on the right-hand side. Also, it can reflect the aspiration preference of optimistic and pessimistic decision makers due to the integration of mλ-measure. The developed method is applied to the long-term planning of a domestic wastewater management system in the city of Kunming, China, with consideration of the eco-environmental protection of downstream water body. The solution results of the GIFCP method can generate a series of optimal wastewater allocation patterns and WTPs capacity expansion schemes under different risk levels, provide in-depth insights into the effects of uncertainties, and consider the proper balance between system cost and risk of constraint violation.

Conjunctive Water Use Optimization for Watershed-Lake Water Distribution System under Uncertainty: a Case Study

In this research, a large-scale inexact optimization method was developed for the conjunctive use management of a watershed-lake water distribution system. The modeling framework has the advantages in taking into account the water balance of multi-reservoirs, satisfying the municipal industrial and agricultural water demands in the multi-period context, reflecting the relationship among multi-reservoirs, multiple water related projects, and maintaining the operational rules of certain lake levels. Moreover, such a method can also handle the uncertainty expressed as fuzzy membership functions through integrating the fuzzy credibility chance-constrained programming. The developed method was applied to the conjunctive use management of water resources in the lake Dianchi watershed, China. Cost-effective water allocation schemes for the groundwater project and the water transfer project, and optimal operational rules for the lake and multiple reservoirs were successfully obtained. Also, the annual water balance of the watershed-lake system and the system cost of the conjunctive water use were investigated and analyzed under multiple credibility levels of meeting the water demands for municipal, industrial and agricultural users.

Lateral hump anomaly of pyramid segment of facial nerve in living patients

Abstract Conclusions: A lateral hump anomaly of the pyramid segment of the facial nerve deserves special attention during otologic surgery. Coronary high-resolution CT (HRCT) reconstruction of temporal bone was highly valuable in preoperative detection of the anomaly. Objective: This study aimed to investigate lateral hump anomaly of the pyramid segment of the facial nerve in adult patients and assess the value of coronary HRCT reconstruction of the temporal bone in preoperative detection of the anomaly. Methods: We carried out a prospective study in 439 Han Chinese adults who underwent unilateral facial nerve decompression due to Bells palsy in our department between April 2005 and October 2012, focusing on lateral hump anomaly of the pyramid segment of the facial nerve, detection sensitivity, and accuracy of coronary HRCT reconstruction of the temporal bone. Results: Lateral hump anomaly of the pyramid segment was observed in 21 cases (4.83%) undergoing surgery. The detection sensitivity and accuracy of coronary HRCT reconstruction were both 100%.

Risk management for sulfur dioxide abatement under multiple uncertainties

In this study, interval-parameter programming, two-stage stochastic programming (TSP), and conditional value-at-risk (CVaR) were incorporated into a general optimization framework, leading to an interval-parameter CVaR-based two-stage programming (ICTP) method. The ICTP method had several advantages: (i) its objective function simultaneously took expected cost and risk cost into consideration, and also used discrete random variables and discrete intervals to reflect uncertain properties; (ii) it quantitatively evaluated the right tail of distributions of random variables which could better calculate the risk of violated environmental standards; (iii) it was useful for helping decision makers to analyze the trade-offs between cost and risk; and (iv) it was effective to penalize the second-stage costs, as well as to capture the notion of risk in stochastic programming. The developed model was applied to sulfur dioxide abatement in an air quality management system. The results indicated that the ICTP method could be used for generating a series of air quality management schemes under different risk-aversion levels, for identifying desired air quality management strategies for decision makers, and for considering a proper balance between system economy and environmental quality.