Biomechanical Comparison of the Roof Step Cut Technique with the Bulk Bone Graft Technique During Total Hip Arthroplasty for Hip Dysplasia: a Finite Element Analysis

PURPOSE OF THE STUDY Different techniques have been reported to reconstruct the defi cient acetabulum during total hip arthroplasty (THA). The purpose of this study was to compare the biomechanical features of the bulk bone graft (BBG) technique (Harris acetabular plasty) and the Roof Step Cut (RSC) technique using fi nite element analysis. MATERIAL AND METHODS Based on a female patient's dysplastic hip CT scan, 3D models were assembled according to the two techniques. For the Harris technique, an irregular BBG was sculpted from a solid sphere, while for the RSC technique, the graft was sculpted into a step-cut shape with a similar size. Each graft was fi xed with two compression screws at two different angles (0° and 45°). Four fi nite element models were used to compare the von Mises stress distribution and total deformation of the grafts and the screws. The pressure and sliding distances of the contacts between the bone graft, metal cup and acetabular host bone were also analyzed. RESULTS For both of the bone grafts and the screws, compared to the Harris models, the maximum stress of the RSC models was signifi cantly lower (16.56 MPa, 25.50 MPa vs 97.13 MPa, 112.72 MPa) and the total deformation was signifi cantly smaller (0.0096 mm, 0.0089 mm vs 0.022 mm, 0.018 mm). 45° inserted screws generated higher stress at the end of the screws and on the outside of the bone graft. In case of 0° inserted screws, the maximum value was mainly located in the middle of the screws, inside the screw channel as well as at the contact area between the graft and the host bone. At all analyzed contacts, the RSC technique shows signifi cantly lower pressure and sliding distances, irrelevant to the screw's insertion angle. In comparison, the model of BBG with 45° screws showed a signifi cant sliding effect and higher contact pressure. CONCLUSIONS Compared with the BBG technique, the step-shaped graft of the RSC technique could signifi cantly reduce the maximum stress and deformation of the graft and the screws, and decrease the pressure and sliding distance between the bone graft, metal cup and the acetabular host bone. The angle of screw placement affects the location of stress and deformation. Key words: developmental dysplasia of the hip, total hip arthroplasty, acetabular reconstruction, bone graft, fi nite element analysis.

Treatment of multiple adjacent RT 1 gingival recessions with the modified coronally advanced tunnel (MCAT) technique and a collagen matrix or palatal connective tissue graft: 9-year results of a split-mouth randomized clinical trial

OBJECTIVES

To evaluate t he long-term outcomes following treatment of RT 1 multiple adjacent gingival recessions (MAGR) using the modified coronally advanced tunnel (MCAT) with either a collagen matrix CM or a connective tissue graft (CTG).

MATERIAL AND METHODS

Sixteen of the original 22 subjects included in a randomized, controlled split-mouth clinical trial were available for the 9-year follow-up (114 sites). Recessions were randomly treated by means of MCAT + CM (test) or MCAT + CTG (control). Complete root coverage (CRC), mean root coverage (MRC), gingival recession depth (GRD), probing pocket depth (PD), keratinized tissue width (KTW), and thickness (KGT) were compared with baseline values and with the 12-month results.

RESULTS

After 9 years, CRC was observed in 2 patients, one in each group. At 9 years, MRC was 23.0 ± 44.5% in the test and 39.7 ± 35.1% in the control group (p = 0.179). The MRC reduction compared to 12 months was - 50.1 ± 47.0% and - 48.3 ± 37.7%, respectively. The upper jaw obtained 31.92 ± 43.0% of MRC for the test and 51.1 ± 27.8% for the control group (p = 0.111) compared to the lower jaw with 8.3 ± 46.9% and 20.7 ± 40.3%. KTW and KGT increased for both CM and CTG together from 2.0 ± 0.7 to 3.1 ± 1.0 mm (< 0.0001). There were no statistically significant changes in PD.

CONCLUSION

The present results indicate that (a) treatment of MAGR using MCAT in conjunction with either CM or CTG is likely to show a relapse over a period of 9 years, and (b) the outcomes obtained in maxillary areas seem to be more stable compared to the mandibular ones.

CLINICAL RELEVANCE

The mean root coverage at 12 months could not be fully maintained over 9 years. On a long-term basis, the results seem to be less stable in the mandible as compared to maxillary areas.

Abdominal Compartment Syndrome After Liver Transplant in Drug-Induced Acute Liver Failure: A Case Report

The incidence of drug-induced acute liver failure (ALF) has been increasing in recent years. Despite the complex intensive treatment, liver transplant should be performed in progressive cases. A systemic inflammatory response syndrome and the burden of surgical intervention promote abdominal compartment syndrome (ACS); observed preoperatively, they are significant negative prognostic factors. THE CASE: We demonstrate a young woman with liver transplant after ALF and a consecutive ACS. We presumed drug toxicity in the background of the rapidly progressive ALF, based on the preoperative hematologic examination and the histology of the removed liver. An ACS has occurred in the postoperative period that must have been resolved with mesh, and later, anatomic segment 2-3 resection had to be performed to further decrease the pressure. The patient left the hospital after 62 days with good graft function. DISCUSSION: A complex intensive care is mandatory in the case of orthotopic liver transplant for ALF. Outcomes are good after orthotopic liver transplant. An ACS might occur after surgery. In these rare cases a delayed abdominal closure or even a liver resection can be the only solution and sometimes an urgent need to resolve the life-threatening problem.

MEASUREMENT OF DIFFERENT COMPONENTS OF SECONDARY RADIATION ONBOARD INTERNATIONAL SPACE STATION BY MEANS OF PASSIVE DETECTORS

The evaluation of different components of secondary radiation (charged fragments and neutrons) onboard ISS is described. Solid-state nuclear track detectors CR-39™ were applied for the measurements of short-range nuclear fragments, while the measurements of neutrons were carried out by means of thermo-luminescent dosimeters with various concentrations of 6Li and 7Li. The flux of charged secondaries and the gamma-equivalent neutron dose are presented in function of the low-LET dose in various modules of the Russian segment of ISS.

Intraosseous structural graft technique: a new surgical concept in the treatment of superolateral defects in case of dysplastic acetabulum, during hip replacement surgery biomechanical and cadaver experimentations

PURPOSE

The replacement of the dysplastic hip, despite the numerous available surgical techniques, is not entirely solved. One of the reasons for this is the relative lack of bone in the acetabulum. In this study, we present a new concept (intraosseous structural graft technique), with the aim to improve the primary stability and biological environment of the graft.

METHODS

During the procedure in the cranial quadrant of the acetabulum, a proximally hinged cortico-spongious plate is fashioned that is opened laterally and a wedge-shaped graft made from the femoral head is impacted. The precisely fitted graft has good primary rotational and cranial stability which is further improved by a bicortical screw.

RESULTS

The hypothesis is supported by examination on 3D models. Cadaver experimentations were performed on 19 hips of 10 cadavers, and stability testing was done on a further 20 hips of 10 cadavers with a material testing apparatus. Also the analysis of the biological and mechanical properties of the graft and the implant were examined.

CONCLUSION

Based on our results, it can be concluded that our technique provides good primary stability with a more favorable biological condition for bony incorporation compared to other bulk bone graft techniques.

Effect of fulvic and humic acids on performance, immune response and thyroid function in rats

Effect of humic acid (HA) and fulvic acid (FA) on production parameters, immune response and thyroid function of rats were investigated in two experiments. First experiment: control or 0.1%, 0.2%, 0.4%, 0.8% HA- or FA-supplemented diets. Second experiment: control and 0.4% HA- or FA-supplemented diets. The feeding period lasted 26 days in both trials. No significant changes were observed in production parameters. Ovalbumine antibody titre of rats on HA- or FA-supplemented diets showed dose-dependent (at 0.4% supplementation) and significant (p < 0.05) increase (350 and 418% respectively) over the control (100%). Dose-related increase of plasma TSH (r = 0.99), and decrease of the T(4)/T(3) ratio (r = -0.97) was observed in FA-supplemented rats. Second experiment: both FA and HA stimulated the immune response by the 14th day (mean values: control: 685.79; FA: 1131.37; HA: 1055.6099) and 26th day (control: 544.31; FA: 1969.83; HA: 1600.00). No significant differences were noted with lymphocyte stimulation test. Diameter of the 'B'-dependent lymphoid tissues in the ileum and spleen were significantly (p < 0.05) larger in both the FA- and HA-treated animals. Humic acid and FA supplementation resulted in strong humoral immune stimulation. Our data also indicate that FA content is responsible for the mild hypothyroid effect of humic substances.

Method for the compilation of a stratified and harmonized soil physical database using legacy and up-to-date data sources

An attempt is outlined for the compilation of an integrated and harmonized stratified soil physical database serving hydrologic modeling, as the basis of estimating soil hydraulic parameters in the unsaturated zone. Due to the appropriate spatial and thematic resolution and data processing status, the Digital Kreybig Soil Information System (DKSIS) and Hungarian Agrogeological Database (HAD) were chosen as pedological and agrogeological data sources for describing the soil physical properties in the unsaturated zone. The DKSIS contains legacy soil data (as hy, pH, salt, OM, CaCO3content, etc.) in finely stratified resolution (3–5 soil layers within 1.5–2.0 m), but lacks particle size data. HAD has a coarser stratification (8–15 layers within 8–10 m) with detailed particle size data. The five-cleft FAO texture classification can serve as an interface in their joint application. The particle size and hy data pairs from the existing Hungarian Soil Monitoring (TIM) network made it possible to define the relation between FAO texture class vs.hyvalue, and based on the HYPRES database each FAO texture class can be characterized by typical Mualem-van Genuchten parameter sets (Wöstenet al., 1999). The compiled, harmonized database characterizes the distinguished soil and sediment layers – with a thickness of at least 10 cm – for a 690 km2large model area, describing their thickness and texture classes to the depth of the permanent groundwater level, in every single square kilometer cell of the model area. The compiled database is indispensable in the model simulation based analysis of regional water management problems like drought, flood and inland inundation.

Y-chromosome markers in Turner syndrome: Screening of 130 patients

BACKGROUND

The presence of Y-chromosome material in patients with Turner syndrome (TS) is a risk factor for the development of gonadoblastoma. Cytogenetic analysis detects Y-chromosome mosaicism in about 5% of Turner patients. However, if Y-chromosome sequences are present in only a few cells, they may be missed by routine analysis. The use of molecular techniques to detect the presence of Y-chromosome fragments in such patients is becoming increasingly important.

AIM

The objective of our study was to analyze cryptic Y-chromosome derivatives in Hungarian TS patient population by real-time PCR (RT-PCR).

SUBJECTS AND METHODS

Cytogenetic and RT-PCR methods were used to examine peripheral blood DNA of 130 Hungarian patients with TS for the presence of Y-chromosome. With RT-PCR, 4 regions throughout the Y-chromosome were analyzed.

RESULTS

Initial cytogenetic karyotyping assessing 10-50 metaphases revealed 3 patients with Y-chromosome positivity. RT-PCR revealed further 6 patients with Y-chromosome, who were initially considered as Y-negatives by standard kayotyping. The consecutive cytogenetic analysis of a large number (about 100) of metaphases (in 5 patients) and/or FISH (in 6 patients) however, also confirmed the presence of the Y-chromosome in these patients. Prophylactic gonadectomy was carried out in all 9 patients and 1 of them was diagnosed as having bilateral gonadoblastoma without clinical symptoms.

CONCLUSIONS

We recommend a routine molecular screening for hidden Y-chromosome sequences in Turner patients, who are negative for Y-chromosome by conventional cytogenetic analysis, in order to calculate the future risk of developing gonadoblastoma.

Parameters of respiratory burst and arachidonic acid metabolism in polymorphonuclear granulocytes from patients with various thyroid diseases

The oxidative processes (oxygen consumption, superoxoid anion generation, arachidonic acid cascade) of human polymorphonuclear granulocytes (PMNs) obtained from patients suffering from thyroid disorders of autoimmune origin (Graves' disease and Hashimoto's thyroiditis), and non autoimmune origin (toxic adenoma) were investigated. All Graves' and toxic adenoma patients were hyperthyroid. Hashimoto's thyroiditis patients were euthyroid. Healthy age and sex matched volunteers served as controls. The results are as follows: 1) In PMNs from both hyperthyroid groups (Graves' disease and toxic adenoma), independently from the autoimmune origin of the disease, a significantly increased Antimycin A sensitive mitochondrial oxygen consumption and a slightly increased superoxide anion generation were detected. 2) In both autoimmune thyroid disease groups (Graves' disease and Hashimoto's thyroiditis)--depending on the functional state of the thyroid gland--a significantly altered intracellular killing activity was measured. 3) An increased arachidonic acid cascade--triggered by opsonized zymozan (OZ)--was detected in both autoimmune thyroid diseases. The increased arachidonic acid cascade was sensitive to phospholipase A2 inhibiting Mepacrin treatment. 4) The PMNs from both autoimmune thyroid diseases produced large amount of leukotriens (LTs)--LTC4 and LTB4--after stimulation through their Fc receptors but the synthesis of prostagalandins (PGs) has not changed. There are no data indicating local, specific effects of circulating leukotriens in the thyroid gland itself, but based on authors' data, their general, regulating role on both the endocrine-- as well as on the immune system--seems to be plausible.

Neutron detection on the Foton-M2 satellite by a track etch detector stack

In the frame of a European Space Agency (ESA) project called 'Biology and Physics in Space', a returning satellite, Foton-M2, was orbiting a container, the BIOPAN-5, loaded with biological experiments and facilities for radiation dosimetry (RADO) in the open space. One of the RADO experiments was dedicated to the detection of the primary cosmic rays and secondary neutrons by a track etch detector stack. The system was calibrated at high-energy particle accelerators and neutron generators. The developed detectors were investigated by an image analyser, and from the track parameters the linear energy transfer spectra and the absorbed dose were determined (26 microGy/d). Also, the neutron flux was estimated below 5 MeV and found to be 2.4 cm(-2) s(-1) directly from the space. The construction of the stack allowed to investigate the neutrons also from the direction of the carrying satellite, where the flux was found somewhat higher.

Occupational 50 Hz magnetic field exposure measurements among female sewing machine operators in Hungary

Occupational magnetic field (MF) exposure is less thoroughly characterized in occupations typically held by women. Our objective was to characterize occupational 50 Hz MF personal exposure (PE) among female sewing machine operators. We measured the full shift PE of 51 seamstresses, who worked in two shifts (6-14 and 14-22 h) according to their normal work routine. Measurements were conducted using EMDEX PAL meters at chest level. The average duration of the measurement periods was 449 min (range 420-470). The average arithmetic mean exposure for all women was 0.76 microT (range 0.06-4.27). The average of maximum values was 4.30 microT (range 0.55-14.80). Women working with older sewing machines experienced higher exposure than women working on newer sewing machines. For women (n = 10) who operated sewing machines produced in 1990 or earlier, the average arithmetic mean exposure was 2.09 microT, and for women (n = 41) who operated sewing machines produced after 1990, the average arithmetic mean was 0.43 microT. We conclude that women working as sewing machine operators experience higher than average occupational MF exposure compared to other working women. Most important determinant of the women's personal MF exposure was the age of the sewing machine the women operated.

Detection of primary and secondary cosmic ray particles aboard the ISS using SSNTD stacks

To study the radiation environment inside the International Space Station, solid state nuclear track detector stacks were used. Within the BRADOS experiments, Phase 1, seven stacks were exposed at different locations of the Russian segment 'Zvezda' for 248 days in 2001. It was supposed that the radiation field inside the ISS was composed from primary cosmic ray particles penetrating the wall of the ISS and secondaries, mainly neutrons induced by primaries in the wall and other structural materials surrounding the detectors. Based on the calibration made by utilising the high energy neutron reference field CERF at CERN (Geneva, Switzerland), the tracks induced by neutrons were separated from those induced by primary particles. Thus, the stacks, on one hand, provided the secondary neutron ambient dose equivalent. On the other hand, from the analysis of the rest of the tracks, the linear energy transfer spectra were computed and the flux and the dose of the primary particles were determined as shown in this paper.

Evaluation of solid state nuclear track detector stacks exposed on the international space station

The aim of the study was to investigate the contribution of secondary neutrons to the total dose inside the International Space Station (ISS). For this purpose solid-state nuclear track detector (SSNTD) stacks were used. Each stack consisted of three CR-39 sheets. The first and second sheets were separated by a Ti plate, and the second and third sheets sandwiched a Lexan polycarbonate foil. The neutron and proton responses of each sheet were studied through MC calculations and experimentally, utilising monoenergetic protons. Seven stacks were exposed in 2001 for 249 days at different locations of the Russian segment 'Zvezda'. The total storage time before and after the exposure onboard was estimated to be seven months. Another eight stacks were exposed at the CERF high-energy neutron field for calibration purposes. The CR-39 detectors were evaluated in four steps: after 2, 6, 12 and 20 h etching in 6 N NaOH at 70 degrees C (VB = 1.34 microm h(-1)). All the individual tracks were investigated and recorded using an image analyser. The stacks provided the averaged neutron ambient dose equivalent (H*) between 200 keV and 20 MeV, and the values varied from 39 to 73 microSv d(-1), depending on the location. The Lexan detectors were used to detect the dose originating from high-charge and high-energy (HZE) particles. These results will be published elsewhere.