Anatomical conditions of the posterior pelvic ring regarding bisegmental transverse sacroiliac screw fixation: a 3D morphometric study of 125 pelvic CT datasets

Introduction

Sacroiliac (SI) screws are used for osteosynthesis in unstable posterior pelvic ring injuries. In the cases of “sacral dysplasia”, in which the elevated upper sacrum does not allow a secure SI screw insertion into the S1 level, the S2 segment must be used to achieve stable fixation. The bone quality of the S2 segment is thinner compared to that of the S1 vertebra and may cause biomechanical weakness. An additional SI screw insertion into the S3 level may improve stability. With respect to the anatomical conditions of the posterior pelvic ring, there have been no anatomical investigations to date regarding SI screw placement into the third sacral segment.

Materials and methods

CT raw datasets from 125 patients (ø59 years, ø172 cm, ø76 kg) were post-processed using Amira 5.2 software to generate 3D pelvic models. A program code implemented in C++ computed a transverse bone corridor for the first, second and third sacral segments for a typical SI screw diameter of 7.3 mm. Volume, sagittal cross-section, iliac entrance area and length of the determined screw corridors were measured. A confidence interval of 95 % was assumed (p < 0.05).

Results

The fully automatic computation revealed a possible transverse insertion for one 7.3-mm screw in the third sacral segment in 30 cases (24 %). The rate (60 %) of feasible S3 screw placements in the cases of sacral dysplasia (n = 25) is significantly higher compared to that (15 %) of “normal” sacra (n = 100). With regard to the existence of transverse iliosacroiliac corridors as a function of sacral position in between the adjacent iliac bone bilaterally, a new classification of three different shape conditions can be made: caudad, intermediate minor, intermediate major, and cephalad sacrum. Gender, age, body height and body weight had no statistically significant influence on either possible screw insertion or on the calculated data of the corridors (p > 0.05).

Conclusion

SI screw insertion into the third sacral level deserves discussion in the cases of sacral dysplasia. Biomechanical and practical utility must be verified.     

Longitudinal changes and seasonal variations in serum 25-hydroxyvitamin D levels in different age groups: results of the Longitudinal Aging Study Amsterdam

Summary

Vitamin D levels remained fairly stable during ageing with increasing levels in persons aged 55–65 years old and decreasing levels in persons aged 65–88 years old. The seasonal variation was larger than the longitudinal change. Our findings implicate that vitamin D supplementation becomes more important in older age groups and during wintertime.

Introduction

Longitudinal changes in serum 25-hydroxyvitamin D (25-OHD) levels during aging have not been studied extensively. Two studies showed increasing serum 25-OHD levels. One of these studies suggested that there might be decreasing levels in persons aged 65 years and older. The objectives of the current study are the following: (1) to examine longitudinal changes in serum 25-OHD levels in different age groups and (2) to describe the seasonal variation in different age groups.

Methods

Data of the Longitudinal Aging Study Amsterdam (LASA), an ongoing cohort study, were used. Two different cohorts were included: (1) younger cohort: aged 55–65 years old at baseline, n?=?738, follow-up of 6 years and (2) older cohort: aged 65–88 years old at baseline, n?=?1,320, follow-up of 13 years.

Results

At baseline, average levels were 56.5 nmol/L in the younger cohort and 51.1 nmol/L in the older cohort. In the younger cohort, a longitudinal increase in the mean serum 25-OHD levels of 4 nmol/L in 6 years was observed; in the older cohort, a longitudinal decrease in the mean serum 25-OHD levels of 4 nmol/L in 13 years was observed. The seasonal variation was ±12 nmol/L in the younger cohort and ±7 nmol/L in the older cohort.

Conclusions

Long-term serum 25-OHD levels remained fairly stable during aging with slightly increasing levels in persons aged 55–65 years old and slightly decreasing levels in persons aged 65–88 years old. On average, the seasonal variation was larger than the longitudinal change. Our findings implicate that vitamin D supplementation becomes more important in older age groups and during wintertime.     

Effect of perioperative complications and functional outcomes on health-related quality of life after radical prostatectomy

Purpose

Radical prostatectomy is a commonly performed procedure with perioperative complication rates of 30 % using standardized reporting methodology. We aim to determine whether perioperative complications and functional outcomes impact quality of life 1 year after surgical treatment.

Patients and methods

Quality of life, functional and oncological outcomes were assessed in patients who underwent open retropubic radical prostatectomy at a single academic institution between 2003 and 2009, preoperatively and 1 year after surgery using the EORTC QLQ-C30, the IIEF-5 and an institutional questionnaire. Perioperative complications were recorded using the Clavien–Dindo classification. Patients without complications were compared to patients with any, low- or high-grade complications. The global health score domain of the EORTC QLQ-C30 is reported for various oncological and functional outcomes and contrasted to stratified categories of complications and functional outcomes.

Results

A full dataset was available for 29.5 % (n = 856) of all patients. The overall complication rate was 27.5 % (235/856). A total of 307 complications were recorded of whom 88.9 % (273/307) were low grade. In this study, population global health perception did not decline after surgery (70.5 ± 21.2 vs. 74.4 ± 19.7; p < 0.0001). Complications showed only statistical but no clinical meaningful influence on global health perception as well as on functional and symptom scales. Patients who met combined outcome criteria experienced the best postoperative global health score (86.0 ± 13.1 and 86.0 ± 14.2).

Conclusions

Perioperative complications and functional outcomes have a measurable impact on quality of life 1 year following surgery. While perioperative complications have a statistical effect, functional outcomes showed a clinically more profound effect on postoperative global health perception.     

Breakdown of Phosphatidylserine Asymmetry Following Treatment of Erythrocytes with Lumefantrine

Background: Lumefantrine, a commonly used antimalarial drug, inhibits hemozoin formation in parasites. Several other antimalarial substances counteract parasitemia by triggering suicidal death or eryptosis of infected erythrocytes. Eryptosis is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine-exposure at the erythrocyte surface. Signaling involved in eryptosis include increase of cytosolic Ca²⁺-activity ([Ca²⁺]_i), formation of ceramide, oxidative stress and/or activation of p38 kinase, protein kinase C (PKC), or caspases. The present study explored, whether lumefantrine stimulates eryptosis. Methods: Cell volume has been estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, [Ca²⁺]_i from Fluo3-fluorescence, reactive oxygen species from 2'',7''-dichlorodihydrofluorescein-diacetate fluorescence, content of reduced glutathione (GSH) from mercury orange fluorescence, and ceramide abundance from binding of fluorescent antibodies in flow cytometry. Results: A 48 h exposure to lumefantrine (3 µg/mL) was followed by a significant increase of annexin-V-binding without significantly altering forward scatter, [Ca²⁺]_i, ROS formation, reduced GSH, or ceramide abundance. The annexin-V-binding following lumefantrine treatment was not significantly modified by p38 kinase inhibitors SB203580 (2 μM) and p38 Inh III (1 μM), PKC inhibitor staurosporine (1 µM) or pancaspase inhibitor zVAD (1 or 10 µM). Conclusions: Lumefantrine triggers cell membrane scrambling, an effect independent from entry of extracellular Ca²⁺, ceramide formation, ROS formation, glutathione content, p38 kinase, PKC or caspases.     

Human endothelial cell-based assay for endotoxin as sensitive as the conventional Limulus Amebocyte Lysate assay

Endotoxin, also known as lipopolysaccharide (LPS) produced by bacteria can be present in any liquid or on any biomaterial even if the material is sterile. Endotoxin in mammals can cause fever, inflammation, cell and tissue damage and irreversible septic shock and death. In the body, endothelial cells making up the blood vasculature and endothelial cells in vitro rapidly react to minute amounts of endotoxin resulting in a rapid induction of the cell adhesion molecule E-selectin. In this study we have used immunofluorescent staining to evaluate the expression of E-selectin on human microvascular endothelial cells from the skin (HDMEC) and human umbilical vein endothelial cells (HUVEC) exposed to various concentrations of LPS. In addition, the sensitivity of detection was compared with the most widely used assay for the presence of endotoxin, the Limulus Amebocyte Lysate assay (LAL). The detection of E-selectin on endothelial cells in the presence of LPS for 4 h was found to be at least as sensitive in detecting the same concentration using the LAL assay. A cell adhesion molecule-enzyme immunosorbent assay was also developed and used to quantify LPS using the endothelial cell model. A comparison of LAL and the immunofluorescent staining method was carried out with solutions, nanoparticles, biomaterial extracts and endothelial cells grown directly on biomaterials. Under all conditions, the endothelial/E-selectin model system was positive for the test samples that were positive by LAL. Thus, we propose the use of this highly sensitive, rapid, reproducible assay for the routine testing of endotoxin in all steps in the manufacturing process of materials destined for use in humans. This can give a rapid feedback and localization of bacterial contamination sources with the LAL being reserved for the testing of the final product.     

The use of external mesh reinforcement to reduce intimal hyperplasia and preserve the structure of human saphenous veins

The saphenous vein is the conduit of choice in bypass graft procedures. Haemodynamic factors play a major role in the development of intimal hyperplasia (IH), and subsequent bypass failure. To evaluate the potential protective effect of external reinforcement on such a failure, we developed an ex vivo model for the perfusion of segments of human saphenous veins under arterial shear stress. In veins submitted to pulsatile high pressure (mean pressure at 100 mmHg) for 3 or 7 days, the use of an external macroporous polyester mesh 1) prevented the dilatation of the vessel, 2) decreased the development of IH, 3) reduced the apoptosis of smooth muscle cells, and the subsequent fibrosis of the media layer, 4) prevented the remodelling of extracellular matrix through the up-regulation of matrix metalloproteinases (MMP-2, MMP-9) and plasminogen activator type I. The data show that, in an experimental ex vivo setting, an external scaffold decreases IH and maintains the integrity of veins exposed to arterial pressure, via increase in shear stress and decrease wall tension, that likely contribute to trigger selective molecular and cellular changes.