A Simple Bedside Technique for Quantifying Volumetric Defects Prior to Hydroxyapatite Cranioplasty.

Contour irregularities following pediatric craniofacial surgery are common. Hydroxyapatite cranioplasty is a successful technique for optimizing the aesthetic outcome in these patients. We describe a simple technique that can be carried out at the bedside to calculate the volume of hydroxyapatite needed and therefore optimize the preoperative planning for hydroxyapatite cranioplasty.

A Weighted Genomic Relationship Matrix Based on Fixation Index (FST) Prioritized SNPs for Genomic Selection.

A dramatic increase in the density of marker panels has been expected to increase the accuracy of genomic selection (GS), unfortunately, little to no improvement has been observed. By including all variants in the association model, the dimensionality of the problem should be dramatically increased, and it could undoubtedly reduce the statistical power. Using all Single nucleotide polymorphisms (SNPs) to compute the genomic relationship matrix (G) does not necessarily increase accuracy as the additive relationships can be accurately estimated using a much smaller number of markers. Due to these limitations, variant prioritization has become a necessity to improve accuracy. The fixation index (FST) as a measure of population differentiation has been used to identify genome segments and variants under selection pressure. Using prioritized variants has increased the accuracy of GS. Additionally, FST can be used to weight the relative contribution of prioritized SNPs in computing G. In this study, relative weights based on FST scores were developed and incorporated into the calculation of G and their impact on the estimation of variance components and accuracy was assessed. The results showed that prioritizing SNPs based on their FST scores resulted in an increase in the genetic similarity between training and validation animals and improved the accuracy of GS by more than 5%.

Auricular reconstruction.

External ear abnormalities are common. These may affect ear shape, size, prominence and degree of development. They may also be associated with hearing loss. The early identification and management of hearing loss is essential. There are several options for reconstruction of the external ear using both autologous and non-autologous techniques. The aim of this article is to outline the different reconstructive options.

Increasing accuracy of genomic selection in presence of high density marker panels through the prioritization of relevant polymorphisms.

BACKGROUND: It becomes clear that the increase in the density of marker panels and even the use of sequence data didn't result in any meaningful increase in the accuracy of genomic selection (GS) using either regression (RM) or variance component (VC) approaches. This is in part due to the limitations of current methods. Association model are well over-parameterized and suffer from severe co-linearity and lack of statistical power. Even when the variant effects are not directly estimated using VC based approaches, the genomic relationships didn't improve after the marker density exceeded a certain threshold. SNP prioritization-based fixation index (FST) scores were used to track the majority of significant QTL and to reduce the dimensionality of the association model. RESULTS: Two populations with average LD between adjacent markers of 0.3 (P1) and 0.7 (P2) were simulated. In both populations, the genomic data consisted of 400 K SNP markers distributed on 10 chromosomes. The density of simulated genomic data mimics roughly 1.2 million SNP markers in the bovine genome. The genomic relationship matrix (G) was calculated for each set of selected SNPs based on their FST score and similar numbers of SNPs were selected randomly for comparison. Using all 400 K SNPs, 46% of the off-diagonal elements (OD) were between - 0.01 and 0.01. The same portion was 31, 23 and 16% when 80 K, 40 K and 20 K SNPs were selected based on FST scores. For randomly selected 20 K SNP subsets, around 33% of the OD fell within the same range. Genomic similarity computed using SNPs selected based on FST scores was always higher than using the same number of SNPs selected randomly. Maximum accuracies of 0.741 and 0.828 were achieved when 20 and 10 K SNPs were selected based on FST scores in P1 and P2, respectively. CONCLUSIONS: Genomic similarity could be maximized by the decrease in the number of selected SNPs, but it also leads to a decrease in the percentage of genetic variation explained by the selected markers. Finding the balance between these two parameters could optimize the accuracy of GS in the presence of high density marker panels.

Correction to: High density marker panels, SNPs prioritizing and accuracy of genomic selection.

CORRECTION TO: BMC GENETICS (2018) 19:4 DOI: 10.1186/S12863-017-0595-2: The original version of this article [1], published on 5 January 2018, contained 3 formatting errors. In this Correction the affected parts of the article are shown. The original article has been updated.

High density marker panels, SNPs prioritizing and accuracy of genomic selection.

BACKGROUND: The availability of high-density (HD) marker panels, genome wide variants and sequence data creates an unprecedented opportunity to dissect the genetic basis of complex traits, enhance genomic selection (GS) and identify causal variants of disease. The disproportional increase in the number of parameters in the genetic association model compared to the number of phenotypes has led to further deterioration in statistical power and an increase in co-linearity and false positive rates. At best, HD panels do not significantly improve GS accuracy and, at worst, reduce accuracy. This is true for both regression and variance component approaches. To remedy this situation, some form of single nucleotide polymorphisms (SNP) filtering or external information is needed. Current methods for prioritizing SNP markers (i.e. BayesB, BayesCπ) are sensitive to the increased co-linearity in HD panels which could limit their performance. RESULTS: In this study, the usefulness of FST, a measure of allele frequency variation among populations, as an external source of information in GS was evaluated. A simulation was carried out for a trait with heritability of 0.4. Data was divided into three subpopulations based on phenotype distribution (bottom 5%, middle 90%, top 5%). Marker data were simulated to mimic a 770 K and 1.5 million SNP marker panel. A ten-chromosome genome with 200 K and 400 K SNPs was simulated. Several scenarios with varying distributions for the quantitative trait loci (QTL) effects were simulated. Using all 200 K markers and no filtering, the accuracy of genomic prediction was 0.77. When marker effects were simulated from a gamma distribution, SNPs pre-selected based on the 99.5, 99.0 and 97.5% quantile of the FST score distribution resulted in an accuracy of 0.725, 0.797, and 0.853, respectively. Similar results were observed under other simulation scenarios. Clearly, the accuracy obtained using all SNPs can be easily achieved using only 0.5 to 1% of all markers. CONCLUSIONS: These results indicate that SNP filtering using already available external information could increase the accuracy of GS. This is especially important as next-generation sequencing technology becomes more affordable and accessible to human, animal and plant applications.

Natural History Analysis of 101 Severe Dysplasia and Esophageal Carcinoma Cases by Endoscopy.

Objectives. Our research is to realize the natural history from dysplasia to carcinoma and to provide evidence for exploring proper screening intervals. Methods. After the onset endoscopy screening, 2093 of the patients participated in the endoscopic follow-up voluntarily. Totally, 101 severe dysplasia and carcinoma cases, either diagnosed in the first endoscopy without treatment or diagnosed in the second endoscopy, were included in our study. We compared the pathologic results of their two endoscopies and calculate the mean and median progression time. Results. Of the 39 severe dysplasia cases diagnosed by the onset endoscopy, only 8 progressed to carcinoma. For severe dysplasia cases diagnosed by the follow-up endoscopy, mean progression times are 55.0, 49.8, and 38.0 months and median progression times are 43, 56, and 31 months for esophagitis, mild dysplasia, and moderate dysplasia, respectively. For superficial carcinoma cases diagnosed by the second endoscopy, mean progression times are 76.0, 57.4, and 47.0 months and median progression times are 77, 63, and 35 months for mild dysplasia, moderate dysplasia, and severe dysplasia, respectively. Conclusions. Population-based severe dysplasia cases may have much lower carcinoma progression rate than specific-selected ones. The progression time for most enrolled cases seems longer than that of the recent screening protocol recommended.

Accuracy of burn size estimation in patients transferred to adult Burn Units in Sydney, Australia: an audit of 698 patients.

BACKGROUND: The purpose of this study was to compare burn size estimation between referring centres and Burn Units in adult patients transferred to Burn Units in Sydney, Australia. METHODS: A review of all adults transferred to Burn Units in Sydney, Australia between January 2009 and August 2013 was performed. The TBSA estimated by the referring institution was compared with the TBSA measured at the Burns Unit. RESULTS: There were 698 adults transferred to a Burns Unit. Equivalent TBSA estimation between the referring hospital and Burns Unit occurred in 30% of patients. Overestimation occurred at a ratio exceeding 3:1 with respect to underestimation, with the difference between the referring institutions and Burns Unit estimation being statistically significant (P<0.001). Significant overestimation occurs in the early transfer of burn-injured patients as well as in patients transferred more than 48h after the burn (P<0.005). Underestimation occurs with less frequency but rises with increasing time after the burn (P<0.005) and with increasing TBSA. Throughout the temporal spectrum of transferred patients, severe burns (≥20% TBSA) were found to have more satisfactory burn size estimations compared with less severe injuries (<20% TBSA; P<0.005). CONCLUSIONS: There are significant inaccuracies in burn size assessment by referring centres. The systemic tendency for overestimation occurs throughout the entire TBSA spectrum, and persists with increasing time after the burn. Underestimation occurs less frequently but rises with increasing time after the burn and with increasing TBSA. Severe burns (≥20% TBSA) are more accurately estimated by the referring hospital. The inaccuracies in burn size assessment have the potential to result in suboptimal treatment and inappropriate referral to specialised Burn Units.

Experience in dermomyofascial pouch coverage of immediate implants following skin sparing reduction mastectomy.

BACKGROUND: Mastectomy for breast cancer treatment and prophylaxis has improved survival for patients. The advantage of implant reconstruction post mastectomy is that it avoids an additional donor site with its associated morbidity, which post-mastectomy autologous reconstruction necessitates. However, the deficiency of muscle coverage at the lower pole of the implant meant it relied on only skin envelope coverage, and thus has the established complication of implant exposure or infection should the skin break down. In 2006, Nava devised a technique for a single-stage reconstruction using definitive breast implants with two-layer coverage of the lower pole with a vascularized dermal layer, as well as the traditional skin envelope, in women with preoperative large ptotic breasts. We present our experience with single-stage implant breast reconstruction using this technique. METHOD: A retrospective review of the medical and operative records as well as patients' photographs was undertaken for consecutive patients from November 2009 to April 2011. These patients were selected for the procedure based on set criteria. We describe our surgical technique for this procedure. RESULT: In the 18-month period, 6 patients underwent 11 skin sparing reduction mastectomy (SSRM) implant reconstructions. Follow-up ranged from 5 to 19 months. The mean length of hospital stay was 7.2 days (range was 2-15 days). One breast out of 11 reconstructions developed an infected seroma 8 months post-operatively, requiring aspiration and intravenous antibiotics. One breast out of 11 developed T junction skin necrosis and associated cellulitis but the breast implant was protected by a visibly vascularized dermal flap and, thus, was not exposed. One breast developed a minor vertical wound dehiscence. CONCLUSION: In our initial experience, SSRM is a safe and effective method of immediate implant-based breast reconstruction.

Sutureless total thyroidectomy: a safe and cost-effective alternative.

BACKGROUND: Advanced vessel sealing devices provide an alternative to conventional ligation techniques for thyroidectomy. To date, most studies have been inadequately powered to explore differences in the infrequent post-operative complications following thyroidectomy. This study is designed to compare the outcomes of sutureless thyroidectomy and conventional thyroidectomy for recurrent laryngeal nerve (RLN) injury, permanent hypoparathyroidism, and haematoma formation. METHODS: A cohort study of consecutive patients undergoing total thyroidectomy using conventional versus sutureless techniques was performed. Sutureless thyroidectomy was performed using either Ligasure Precise (Covidien) or Harmonic Focus (Johnson and Johnson) devices. The primary outcome measures were post-operative haemorrhage, permanent RLN injury and hypoparathyroidism. Secondary outcome measures were operative time, temporary hypoparathyroidism and vocal cord dysfunction. A cost minimization analysis comparing the two techniques was performed. RESULT: From January 2006 to July 2009, 1935 consecutive patients underwent total thyroidectomy. Of these, 772 underwent conventional thyroidectomy and 1163 were performed using a sutureless technique. The mean operative time was significantly lower in the sutureless group (71 versus 86 min, P = 0.02). There was no difference in the post-operative complications of haematoma (0.78% conventional versus 1.12% sutureless, P = 0.46), permanent hypoparathyroidism (1.30% conventional versus 0.52% sutureless, P = 0.06) or permanent RLN injury (0.26% conventional versus 0.52% sutureless, P = 0.39). There was an overall cost saving of AUD$14,300 per 100 total thyroidectomy cases performed using the sutureless technique. CONCLUSIONS: Sutureless thyroidectomy is a safe and efficient way of performing total thyroidectomy and has the potential to reduce operating room costs.