Portal Venous Pressure in Adult Living Donor Liver Transplantation

Objective

The relationship between portal pressure and small-for-size syndrome (SFSS) is unsettled. The purpose of this study was to evaluate the role of portal pressure in predicting SFSS.

Methods

Thirty-four patients with end-stage liver disease who received adult-to-adult living-donor liver transplantation (ALDLT) were included. Recipients were grouped based on whether they received portal flow modulation or not. The intraoperative portal vein flow volume (PVFV) and portal venous pressure (PVP) between the 2 groups were compared. The relationship of PVP to PVFV, graft weight-to-recipient weight ratio (GRWR), and graft weight-to-recipient spleen size ratio (GRSSR) were analyzed.

Results

Persistent portal hypertension was found after ALDLT. The PVP was linearly correlated with PVFV but not with GRWR or GRSSR. With the use of the following criteria, (1) PVFV >250 mL/min/100 g graft weight, (2) GRWR <0.8%, and (3) GRSSR <0.6, modulation of the portal flow was performed in 3 cases. The receiver operating characteristic analysis showed that 23 mm Hg was the cutoff point for PVP, with a sensitivity of 83% and specificity of 43%.

Conclusions

PVP is a weak parameter to use for portal flow modulation after ALDLT. It is sensitive but not specific to predict SFSS.     

Design Method of a Foldable Ventricular Assist Device for Minimally Invasive Implantation

To date, ventricular assist devices (VADs) have become accepted as a therapeutic solution for end‐stage heart failure patients when a donor heart is not available. Newer generation VADs allow for a significant reduction in size and an improvement in reliability. However, the invasive implantation still limits this technology to critically ill patients. Recently, expandable/deployable devices have been investigated as a potential solution for minimally invasive insertion. Such a device can be inserted percutaneously via peripheral vessels in a collapsed form and operated in an expanded form at the desired location. A common structure of such foldable pumps comprises a memory alloy skeleton covered by flexible polyurethane material. The material properties allow elastic deformation to achieve the folded position and withstand the hydrodynamic forces during operation; however, determining the optimal geometry for such a structure is a complex challenge. The numerical finite element method (FEM) is widely used and provides accurate structural analysis, but computation time is considerably high during the initial design stage where various geometries need to be examined. This article details a simplified two‐dimensional analytical method to estimate the mechanical stress and deformation of memory alloy skeletons. The method was applied in design examples including two popular types of blade skeletons of a foldable VAD. Furthermore, three force distributions were simulated to evaluate the strength of the structures under different loading conditions experienced during pump operation. The results were verified with FEM simulations. The proposed two‐dimensional method gives a close stress and deformation estimation compared with three‐dimensional FEM simulations. The results confirm the feasibility of such a simplified analytical approach to reveal priorities for structural optimization before time‐consuming FEM simulations, providing an effective tool in the initial structural design stage of foldable minimally invasive VADs.     

Segmental ureterectomy does not compromise the oncologic outcome compared with nephroureterectomy for pure ureter cancer

Purpose

Pure ureter cancers are rare and account for only 1–3 % of urothelial carcinomas with limited data. Nowadays, nephron-sparing methods are reserved mainly for imperative cases. This study intends to assess the oncologic outcome between segmental ureterectomy (SU) and radical nephroureterectomy (RNU) for pure ureteral urothelial carcinoma.

Methods

From July 2004 to August 2010, 112 patients at a single tertiary referral center were included. Perioperative data were obtained from our institutional database. Postoperative CT scan, cystoscopy, and contralateral renal echo were performed regularly for survey of disease recurrence.

Results

The mean length of follow-up was 43.8 and 48.3 months for the RNU and SU group, respectively. The bladder recurrences, local recurrences, distant metastasis, and cancer-specific survival rates showed no significant differences between RNU and SU (36.4 vs. 34.2 %, p = 0.83; 23.4 vs. 14.3 %, p = 0.27; and 16.9 vs. 8.6 %, p = 0.244, and 13.0 vs. 5.7 %, p = 0.249, respectively).

Conclusion

The study suggested that SU is not inferior to RNU for ureter cancer in oncologic outcomes and is less invasive and better nephron preservation.     

Chylothorax Complicating Video-Assisted Thoracoscopic Surgery for Non-small Cell Lung Cancer

Background

Chylothorax is an infrequent but well-known complication in lung cancer surgery. Previous published studies on this topic are limited, and thoracotomy has been the main surgical approach for treatment. However, chylothorax after lung cancer surgery performed solely by video-assisted thoracoscopic surgery (VATS) has rarely been investigated. The purpose of this study is to evaluate chylothorax after VATS for lung cancer.

Methods

The records of 776 patients with primary non-small-cell lung cancer (NSCLC) who underwent VATS for pulmonary resection and mediastinal lymph node dissection (MLND) at our hospital from January 2010 to August 2013 were retrospectively reviewed. Twenty patients with chylothorax (2.58 %) were included in the analysis.

Results

The 20 patients with chylothorax were all treated conservatively, but five patients (25 %) subsequently required reoperation for chylothorax. In patients with pleural drainage of less than 400 ml the first postoperative day, the chylothorax resolved with conservative treatment. Chylothorax also resolved in patients with pleural drainage of more than 400 ml the first or second postoperative day if drainage was less than 400 ml on postoperative day 4 and thereafter. Reoperations were required in cases with an increasing amount of pleural drainage on postoperative day 4 and thereafter.

Conclusions

Most of the chylothorax following VATS for lung cancer can be treated conservatively. However, the timing of surgical intervention for chylothorax following VATS for lung cancer can be earlier if pleural drainage does not show a trend toward decreasing with conservative treatment.     

Anaemia management in patients with chronic kidney disease: Taiwan practice guidelines

The introduction of erythropoiesis‐stimulating agents (ESAs) markedly improved the lives of many anaemic patients with chronic kidney disease (CKD). In Taiwan, the strategy of management of anaemia in patients with CKD was different from many other parts of the world. In 1996, the National Health Insurance Administration of Taiwan applied a more restrictive reimbursement criteria for ESA use in patients with CKD. ESA is to be initiated when non‐dialysis CKD patients have a serum creatinine >6 mg/dL and a hematocrit <28% to maintain a hematocrit level not exceeding 30%. The maximal dose of epoetin‐α or β was 20 000 U per month. The target haemoglobin range and dose limitation for ESAs were the same for dialysis CKD patients. Thus, long before randomized controlled trials showing an increased risk for cardiovascular events at nearly normal haemoglobin concentrations and higher ESA doses in CKD, nephrologists in Taiwan had avoided the use of disproportionately high dosages of ESAs to achieve a haemoglobin level of 10–11 g/dL. Moreover, intravenous iron supplementation was encouraged earlier in Taiwan in 1996, when we reached consensus on the diagnostic criteria for iron deficiency (serum ferritin <300 ng/mL and/or transferrin saturation <30%). The experience of CKD anaemia management in Taiwan demonstrated that a reasonable haemoglobin target can be achieved by using the lowest possible ESA dose and intravenous iron supplementation.     

The Role of Integrin αv in Proliferation and Differentiation of Human Dental Pulp Cell Response to Calcium Silicate Cement

Introduction

It has been proved that integrin αv activity is related to cell proliferation, differentiation, migration, and organ development. However, the biological functions of integrin αv in human dental pulp cells (hDPCs) cultured on silicate-based materials have not been explored. The aim of this study was to investigate the role of integrin αv in the proliferation and odontogenic differentiation of hDPCs cultured with the effect of calcium silicate (CS) cement and β-tricalcium phosphate (TCP) cement.

Methods

In this study, hDPCs were cultured on CS and TCP materials, and we evaluated fibronectin (FN) secretion and integrin αv expression during the cell attachment stage. After small interfering RNA transfection targeting integrin αv, the proliferation and odontogenesis differentiation behavior of hDPCs were analyzed.

Results

The results indicate that CS releases Si ion–increased FN secretion and adsorption, which promote cell attachment more effectively than TCP. The CS cement facilitates FN and αv subintegrin expression. However, the FN adsorption and integrin expression of TCP are similar to that observed in the control dish. Integrin αv small interfering RNA inhibited odontogenic differentiation of hDPCs with the decreased formation of mineralized nodules on CS. It also down-regulated the protein expression of multiple markers of odontogenesis and the expression of dentin sialophosphoprotein protein.

Conclusions

These results establish composition-dependent differences in integrin binding and its effectiveness as a mechanism regulating cellular responses to biomaterial surface.     

New horizontal v-shaped osteotomy for correction of protrusion of the zygoma and the zygomatic arch in East Asians: indication and results

Protrusion of the zygoma is commonly considered undesirable and unattractive among East-Asians, and many try to achieve a harmonious oval midface by having various cosmetic operations. However, effective contouring for a severe protruding zygoma has rarely been reported .The objectives of this study therefore were to investigate the feasibility and effectiveness of a horizontal V-shaped ostectomy for correction of protrusion of the zygoma and zygomatic arch, and to discuss its indications. From January 2008 to December 2011 we treated 27 patients by contouring of the zygoma with a horizontal V-shaped ostectomy through intraoral and preauricular incisions. The effectiveness was then evaluated with cephalometric radiographs, 3-dimensional computed tomography, and standard facial photographs taken before and after operation. The postoperative appearance of all 27 patients showed that the protrusion had been effectively reduced with no serious complications, and the facial contour had improved. The ?nal aesthetic outcomes were satisfactory for both surgeons and patients. The horizontal V-shaped osteotomy is a good technique for the reduction of protrusion of the zygoma and zygomatic arch, and it has the advantages of more convenient multishifting, better results, and fewer complications. It also ensures the integrity of the structure of the malar complex.     

Biomechanical effects of the implant material and implant–abutment interface in immediately loaded small-diameter implants

Objective

Small-diameter implants have been available since the 1990s, but few studies have analyzed their mechanical properties. This study evaluated the effects of the implant material and the implant–abutment connection designs on the primary stability and the marginal bone strain of small-diameter implant subject to immediate loading.

Materials and methods

Insertion torque value (ITV), implant stability quotient (ISQ), and Periotest value (PTV) of three implant systems with four parameters (titanium, titanium alloy, internal and external hexagon connections) were measured after placing implants into artificial type 2 jaw-bone models. Specimens were tested under both vertical and oblique static loads at 190 N. Peak values of the principal bone strain were recorded and analyzed statistically by the Kruskal–Wallis test and multiple-comparisons Bonferroni test.

Results

PTV and ISQ were higher for the NIOSM311 (internal-hex and Ti alloy) and FOSM311 (external-hex and pure Ti) implants, respectively, than for the NOSM311 (external-hex and Ti alloy) implant. Under vertical loading the peak value of peri-implant bone strains did not differ significantly among these three implant systems. However, the peak bone strains were at least 32 % lower for the NIOSM311 and FOSM311 implants than for the NOSM311 implant under lateral loading.

Conclusions

The implant material and the implant–abutment connection design significantly influence the peri-implant bone strain of immediately loaded small-diameter implants, but barely affect their primary stability.

Clinical Relevance

A commercially pure titanium implant with an internal connection has the potential to reduce the risk of implant failure of small-diameter implant related to biomechanical complications.     

Assessing short and long‐term educational impact of visits to hospice via a combination of qualitative methods

While qualitative methods have gained considerable recognition in medical education research, employing multiple qualitative data sources in assessing long‐term educational impact is rare. Utilising in‐depth data analysis method to six cross‐sectional cohorts (2004–2009) of students’ reflection papers (n = 213), this article demonstrates how students experienced subtle but important shifts in their attitudes (including personal, professional and spiritual domains) after making field visits to a hospice centre as part of the Special Needs Dentistry module. For retrospective assessment of learning retention, a pilot focus group was conducted with three junior faculty members who participated in the field visits to a hospice during their own undergraduate training. A subsequent focus group was conducted with graduates of the 2008 (n = 8) cohort using a refined discussion guide arising from the analysis of pilot group results. Graduates were unanimous in stating that the visits had sown ‘seeds’ in their minds and hearts, seeds which started to grow after they completed dental school and began to practice. This is demonstrative of the long‐term positive educational impact of the pedagogical design that entailed a special site visit coupled with post‐visit debrief and written reflection.