Suture cruroplasty versus prosthetic hiatal herniorrhaphy for large hiatal hernia: a meta-analysis and systematic review of randomized controlled trials

OBJECTIVE: The aim was to conduct a meta-analysis of randomized controlled trials (RCTs) comparing 2 methods of hiatal closure for large hiatal hernia and to evaluate their strengths and flaws. METHODS: Prospective RCTs comparing suture cruroplasty versus prosthetic hiatal herniorrhaphy for large hiatal hernia were selected by searching PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane Central Register of Controlled Trials published between January 1991 and October 2014. The outcome variables analyzed included operating time, complications, recurrence of hiatal hernia or wrap migration, and reoperation. These outcomes were unanimously decided to be important because they influence the practical approach toward patient management. Random effects model was used to calculate the effect size of both dichotomous and continuous data. Heterogeneity among the outcome variables of these trials was determined by the Cochran's Q statistic and I index. The meta-analysis was prepared in accordance with Preferred Reporting of Systematic Reviews and Meta-Analyses guidelines. RESULTS: Four RCTs were analyzed totaling 406 patients (Suture = 186, Prosthesis = 220). For only 1 of the 4 outcomes, ie, reoperation rate (OR 3.73, 95% CI 1.18, 11.82, P = 0.03), the pooled effect size favored prosthetic hiatal herniorrhaphy over suture cruroplasty. For other outcomes, comparable effect sizes were noted for both groups which included recurrence of hiatal hernia or wrap migration (OR 2.01, 95% CI 0.92, 4.39, P = 0.07), operating time (SMD -0.46, 95% CI -1.16, -0.24, P = 0.19) and complication rates (OR 1.06, 95% CI 0.45, 2.50, P = 0.90). CONCLUSIONS: On the basis of our meta-analysis and its limitations, we believe that the prosthetic hiatal herniorrhaphy and suture cruroplasty produces comparable results for repair of large hiatal hernias. In the future, a number of issues need to be addressed to determine the clinical outcomes, safety, and effectiveness of these 2 methods for elective surgical treatment of large hiatal hernias. Presently, the use of prosthetic hiatal herniorrhaphy for large hiatal hernia cannot be endorsed routinely and the decision for the placement of mesh needs to be individualized based on the operative findings and the surgeon's recommendation

Expository of modified geostatistical models of Teak stands volume specific to Solomon Island-derived clones in Tawau, Sabah Malaysia

The geostatistical model of the teak tree’s volume was examined based on a teak plantation managed by the research and development team of Sabah Softwood Berhad, at Brumas camp, Tawau, Sabah. A sample of 432 and 445 georeferenced individual tree points obtained for the 6th and 7th year respectively, was analysed, specific to the Solomon Island-derived clone as previous findings showed that it was the genotype that thrived. This study aims to expose the possibility that the modified theoretical variogram model for the volume of the teak tree, with piecewise function, fits the data better than previously introduced theoretical variograms. The modified theoretical variogram is compared to previously introduced theoretical variograms to examine its accuracy and consistency according to the volume’s spatial information. The introduction of the piecewise function into the modified theoretical variograms proves to be a better fit for the variograms via plots, further smoothening of the piecewise function needs to be executed to prove that it has lower error and higher accuracy when estimation using kriging needs to be executed

Specifying Spatial Dependence for Teak Stands Specific to Solomon Island-Derived Clones in Tawau, Sabah, Malaysia: A Preliminary Study

The magnitude of spatial dependence on teak tree growth was examined based on a teak plantation managed by the research and development team at Sabah Softwood Berhad, Brumas camp, Tawau, Sabah, Malaysia. A sample of 432 and 445 georeferenced individual tree points specific to Solomon Island-derived clones that were 6 and 7 years old, respectively, were analyzed, as previous findings showed that this was the genotype that thrived the most. This study aims to show that spatial dependence exists in the 6-and 7-year-old teak tree blocks of the plantation and that there are changes in the magnitude of spatial dependence when it is analyzed as a continuous plot. Moran’s I values and Moran scatterplots as well as semivariograms and thematic maps were used to satisfy the hypothesis regarding the relationship between spatial dependence and the growth of the physical parameters: the diameter at breast height (DBH), height, and the volume of the teak tree. The Moran’s I values that were calculated rejected the null hypothesis, suggesting the existence of strong spatial dependence for all of the physical parameters and for both the 6-and 7-year-old samples. The semivariograms were plotted and showed an increasing trend as the lag distance between trees increased and showed changes as the trees aged. These findings prove significant spatial dependence in the growth of the physical parameters of teak trees. Hence, growth model methodologies based on spatial distribution must be developed to further understand the spatial distribution of teak tree plantations

Spatial functional outlier detection in multivariate spatial functional data

Multivariate spatial functional data consists of multiple functions of time-dependent attributes observed at each spatial point. This study focuses on detecting spatial outliers in spatial functional data. Firstly, we develop a new method called Mahalanobis Distance Spatial Outlier (MDSO) to detect functional outliers in the data. The method introduces the multivariate functional Mahalanobis semi-distance and multivariate pairwise functional Mahalanobis semi-distance metrics based on the multivariate functional principal components analysis to calculate the dissimilarity between functions at each spatial point. Via simulation, we show that MDSO performs better than the other competing methods. Secondly, MDSO has been extended to detect spatial functional outliers as well. The functional outliers can now be categorized as global or/and local functional outliers. The appropriate number of neighbors and the cut-off point for the degree of isolation are determined via simulation. Finally, we demonstrate the application of the MDSO on a water quality data set obtained from Sungai Klang basin in Malaysia. The results can be used to support the authority in making better decisions on the management of the river basin or other spatial data with time-independent attributes

Improved spatial outlier detection method within a river network

A spatial outlier refers to the observation whose non-spatial attribute values are significantly different from those of its neighbors. Such observations can also be found in water quality data at monitoring stations within a river network. However, existing spatial outlier detection procedures based on distance measures such as the Euclidean distance between monitoring stations do not take into account the river network topology. In general, water quality levels in lower streams will be affected by the flow from the upper streams. Similarly, the water quality at some tributaries may have little influence on the other tributaries. Hence, a method for identifying spatial outliers in a river network, taking into account the effect of river flow connectivity on the determination of the neighbors of the monitoring stations, is proposed. While the robust Mahalalobis distance is used in both methods, the proposed method uses river distance instead of the Euclidean distance. The performance of the proposed method is shown to be superior using a synthetic river dataset through simulation. For illustration, we apply the proposed method on the water quality data from Sg. Klang Basin in 2016 provided by the Department of Environment, Malaysia. The finding provides a better identification of the water quality in some stations that significantly differ from their neighbouring stations. Such information is useful for the authorities in their planning of the environmental monitoring of water quality in the areas

Laparoscopic vs open repair for incisional hernia

OBJECTIVES: The aim was to conduct a meta-analysis of RCTs investigating the surgical and postsurgical outcomes of elective incisional hernia by open versus laparoscopic method. MATERIAL AND METHODS: A search of PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane Central Register of Controlled Trials published between January 1993 and September 2013 identified all the prospective RCTs comparing surgical treatment of only incisional hernia (and not primary ventral hernias) using open and laparoscopic methods were selected. The outcome variables analyzed included (a) hernia diameter; (b) operative time; (c) length of hospital stay; (d) overall complication rate; (e) bowel complications; (f) reoperation; (g) wound infection; (h) wound hematoma or seroma; (i) time to oral intake; (j) back to work; (k) recurrence rate; and (l) post-operative neuralgia. The quality of RCTs was assessed using Jadad's scoring system. Random effects model was used to calculate the effect size of both binary and continuous data. Heterogeneity amongst the outcome variables of these trials was determined by the Cochran Q statistic and I2 index. The meta-analysis was prepared in accordance with PRISMA guidelines. RESULTS: Six RCTs were considered suitable for meta-analysis. A total of 378 patients underwent open mesh repair and 373 had laparoscopic repair. Statistically significant reduction in bowel complications was noted with open surgery compared to the laparoscopic repair in five studies (OR 2.56, 95% CI 1.15, 5.72, p=0.02). Comparable effects were noted for other variables which include hernia diameter (SMD -0.27, 95% CI -0.77, 0.23, p=0.29), operative time (SMD -0.08, 95% CI -4.46, 4.30, p=0.97), overall complications (OR -1.07, 95% CI -0.33, 3.42, p=0.91), wound infection (OR 0.49, 95% CI 0.09, 2.67, p=0.41), wound hematoma or seroma (OR 1.54, 95% CI 0.58, 4.09, p=0.38), reoperation rate (OR -0.32, 95% CI 0.07, 1.43, p=0.14), time to oral intake (SMD -0.16, 95% CI -1.97, 2.28, p=0.89), length of hospital stay (SMD -0.83, 95% CI -2.22, 0.56, p=0.24), back to work (SMD -3.14, 95% CI -8.92, 2.64, p=0.29), recurrence rate (OR 1.41, 95% CI 0.81, 2.46, p=0.23), and postoperative neuralgia (OR 0.48, 95% CI 0.16, 1.46, p=0.20). CONCLUSIONS: On the basis of our meta-analysis, we conclude that laparoscopic and open repair of incisional hernia is comparable. A larger randomized controlled multicenter trial with strict inclusion and exclusion criteria and standardized techniques for both repairs is required to demonstrate the superiority of one technique over the other

A new crescent moon visibility criteria using circular regression model: a case study of Teluk Kemang, Malaysia

Many astronomers have studied lunar crescent visibility throughout history. Its importance is unquestionable, especially in determining the local Islamic calendar and the dates of important Islamic events. Different criteria have been used to predict the possible visibility of the crescent moon during the sighting process. However, so far, the visibility models used are based on linear statistical theory, whereas the useful variables in this study are in the circular unit. Hence, in this paper, we propose new visibility tests using the circular regression model, which will split the data into three visibility categories; visible to the unaided eye, may need optical aid and not visible. We formulate the procedure to separate the categories using the residuals of the fitted circular regression model. We apply the model on 254 observations collected at Baitul Hilal Teluk Kemang Malaysia, starting from March 2000 to date. We show that the visibility test developed based on elongation of the moon (dependent variable) and altitude of the moon (independent variable) gives the smallest misclassification rate. From the statistical analysis, we propose the elongation of the moon 7.28°, altitude of the moon of 3.33° and arc of vision of 3.74 at sunset as the new crescent visibility criteria. The new criteria have a significant impact on improving the chance of observing the crescent moon and in producing a more accurate Islamic calendar in Malaysia

Outlier detection in a circular regression model

Recently, there is strong interest on the subject of outlier problem in circular data. In this paper, we focus on detecting outliers in a circular regression model proposed by Down and Mardia. The basic properties of the model are available including the exact form of covariance matrix of the parameters. Hence, we intend to identify outliers in the model by looking at the effect of the outliers on the covariance matrix. The method resembles closely the COVRATIO statistic for the case of linear regression problem. The corresponding critical values and the performance of the outlier detection procedure are studied via simulations. For illustration, we apply the procedure on the wind data set

Benefits of early feeding versus traditional nil-by-mouth nutritional postoperative management in gastrointestinal resectional surgery patients: a meta-analysis

The objective of the current work was to conduct a meta-analysis of randomized controlled trials evaluating the effect on surgical outcomes of providing nutrition within 24-hours following gastrointestinal surgery compared with traditional postoperative management. A literature search was conducted to identify randomized controlled trials published in English language between1966 and 2007 comparing the outcomes of early and traditional postoperative feeding. All trials involving resection of the portions of the gastrointestinal tract followed by patients receiving nutritionally significant oral or enteral intake within 24-hours after surgery were included for analysis. Random effects meta-analyses were performed. Outcome variables analyzed were complications, mortality, anastomotic dehiscence, nasogastric reinsertion, days to passing flatus, days to first bowel motion, and length of stay. Fifteen studies (n=1240 patients) were analyzed. A statistically significant forty-five percent reduction in relative odds of total postoperative complications were seen in patients receiving early postoperative feeding (OR 0.55 CI 0.35, 0.87, p=0.01). No effect of early feeding was seen with relation to anastomotic dehiscence (OR 0.75, CI 0.39, 1.4, p=0.39), mortality (OR 0.71, CI 0.32,1.56, p= 0.39), resumption of bowel function as evidenced by days to passage of flatus (WMD -0.42, CI -1.12, 0.28, p=0.23) and first bowel motion (WMD -0.28, CI -1.20, 0.64, p=0.55), or reduced length of stay (WMD -1.28, CI -2.94, 0.38, p=0.13). Similarly, nasogastric tube reinsertion was less common in traditional feeding interventions, however this was not statistically significant (OR 1.48, CI 0.93, 2.35, p=0.10). Early provision of nutritionally significant oral or enteral intake is associated with a significant reduction in reported total complications when compared with traditional postoperative feeding practices and does not negatively affect outcomes such as mortality, anastomotic dehiscence, resumption of bowel function or hospital length of stay. For these reasons, surgeons should be confident in adopting early feeding as part of standard practice for elective gastrointestinal surgery