Search

Resume Introduction Dans la stenose canalaire lombaire degenerative, la relation entre la variabilite des symptomes et la severite de la compression est mal comprise. Ainsi, un autre facteur pouvant influencer le resultat clinique de ces patients a ete evoque : la presence de comorbidites. L’objectif de cette etude etait d’analyser le role des comorbidites sur les resultats cliniques et les scores fonctionnels de patients suivis pour stenose canalaire lombaire. Methodes Dans cette etude prospective, les patients traites pour stenose canalaire lombaire ont ete consecutivement inclus durant une annee. Le diagnostic de stenose lombaire etait realise apres un examen clinique et radiologique. Les donnees demographiques, cliniques et radiographiques etaient recueillies. Deux questionnaires ont ete utilisees pour evaluer la gene fonctionnelle : un score specifique aux stenoses lombaires (l’auto-questionnaire Beaujon) et un score non specifique (le Short Form 36, SF36). Quatre scores de comorbidite ont ete calcules : cumulative illness rating scale, Charlson index, functional comorbidity index et index of coexistent diseases. Les correlations entre les scores fonctionnels et de comorbidites ont ete effectuees. Resultats Au total, 250 patients ont ete inclus, d’âge moyen 65,6 ± 12 ans. Les quatre scores de comorbidites etaient significativement correles a l’auto-questionnaire Beaujon, ainsi qu’aux sous-dimensions « lombaire » et « ischemie radiculaire » de ce score. Les meilleures correlations etaient observees entre le cumulative illness rating scale et l’auto-questionnaire Beaujon ; deux facteurs influencaient significativement cette relation : l’existence d’une hernie discale et la composante « general health » du SF36. Discussion Cette etude met en evidence l’existence d’une influence des comorbidites sur les signes fonctionnels des patients atteints de stenose canalaire lombaire. De plus, des correlations existent entre les comorbidites et les symptomes liees a la lombalgie ou a la claudication, contrairement a la douleur radiculaire isolee. Par consequent, les comorbidites semblent avoir un role dans la variabilite de la presentation clinique de ces patients en preoperatoire et ceci pourrait etre inclus dans l’information des patients. L’influence des comorbidites sur les resultats postoperatoires necessite d’etre exploree.

Introduction In degenerative lumbar spinal stenosis (DLSS) variability of symptoms according to the severity of stenosis is not well understood. Therefore, another factor that impacts functional outcomes of DLSS patients has been evoked: patient's comorbidities. The aim of this study was to investigate influence of comorbidities on clinical symptoms and functional outcomes in DLSS patients. Methods In this prospective study, patients treated for DLSS were included during 12 consecutive months. Both clinical and radiographic exams were required to confirm DLSS diagnosis. Epidemiologic, clinical and radiographic data were collected. Two questionnaires were used to assess functional outcomes: a specific score dedicated to lumbar stenosis consequences assessment (self-administered Beaujon questionnaire, SABQ) and a non-specific score (Short Form 36, SF-36). Four comorbidity scores were calculated: Cumulative Illness Rating Scale, Charlson index, Functional Comorbidity Index and Index of Co-Existent Diseases Correlations between functional and comorbidity scores were calculated. Results 250 patients were included (65.6 ± 12 years). The four comorbidities scores were significantly correlated to total SABQ, as well as lumbar and radicular ischemia components. Best correlations were observed for cumulative illness rating scale and SABQ. Two factors were observed that significantly influenced the relationship between SABQ and cumulative illness rating scale: herniated disc and SF-36 general health perception. Discussion This study highlighted that preoperative function is influenced by comorbidities in DLSS patients. Relationships existed between comorbidities and symptoms related to low back pain and neurogenic claudication, contrary to radicular pain. Therefore, comorbidities might impact the variability of patients’ outcomes. This finding should be part of the patient's preoperative information. Moreover, role of comorbidities on postoperative outcomes need to be investigated.

Primary refined softwood was subjected to high-consistency (HC) or low-consistency (LC) secondary refining, and the nature of the development of the internal and external fiber microstructure and ultrastructure has been compared. The primary refining of mixed softwood as a raw material was performed in pilot scale by the advanced thermomechanical pulp process. The study was aiming at the comparative characterization of LC and HC pulps at the fiber level when produced with similar and well-characterized handsheet properties. The formerly described Simons’ staining method was applied. A significant degree of fiber wall delamination/internal fibrillation (D/IF) was observed during both LC and HC refining. Both the energy input and the refining consistency had a significant impact on elevating the degree of fiber wall D/IF. The statistical evaluation of internal fiber development indicated that the fiber populations in LC- and HC-refined pulps had a similar degree of fiber wall D/IF despite having a large difference in refining energy input (420 kW h odt-1), confirming that D/IF was promoted more energy-efficiently in LC than in HC refining. The characteristic of the external fiber development from HC and LC refining was very different. Secondary LC refining promoted fiber surfaces with ribbons of thin hairlike threads arising from the inner secondary S2 layer that occasionally developed along the whole fiber length. Broad sheet- and lamellae-type external fibrillation from the S2 was typical for HC refining, and these characteristics were rarely observed in the LC pulps. The mechanisms for LC and HC fiber development are proposed. The cell wall characteristics (internal and external) of the pulp fibers appear to govern most of the physical and optical properties in handsheets.

STUDY DESIGN Technical note and retrospective first cases study. OBJECTIVE To present a novel surgical procedure for treating rare and challenging U-shaped fractures of the sacrum. SUMMARY OF BACKGROUND DATA U-shaped fractures of the sacrum are not frequent and usually seen in the context of high energy trauma (high-fall injury). There is no consensus about the therapeutic strategy. When surgery is decided on selected patients, the technique raises several issues for the neural decompression, reduction, and fixation. The L5-S1 mobility has to be sacrificed for most authors. METHODS Based on anatomic considerations, the authors present here the original surgical technique they have been using at their institution and a consecutive series of patients. The procedure associates a shortening osteotomy of the sacrum at the site of the fracture and a sacro-sacral fixation. RESULTS The proposed procedure was simple, safe, and effective. CONCLUSIONS Performing the osteotomy helps in the reduction and allows a short fixation, which spares the mobility of the lumbo-sacral junction.

Two different enzyme applications were applied to black spruce thermomechanical pulping (TMP) in an attempt to selectively enhance the physical properties of the resulting pulp. Past studies have revealed some application difficulties between pulp and enzymes. A new method of enzyme application including fiberizing the wood chips and cooling the fiberized material prior to enzyme application was employed to maximize the fiber surface area available for enzyme reaction and to obtain optimal enzyme reaction temperatures. Fiberized chips are chips that have been destructured in a converging screw chip press followed by low energy refining to produce extremely coarse fiber pulp. TMP pulps obtained from a control sample of whole wood chips, fiberized wood treated with water, and fiberized wood with two different enzyme applications were evaluated for specific refining energy and various physical properties. Scanning electron microscopy (SEM) in conjunction with image analysis techniques was used to determine f...

Eucalyptus wood chips were subjected to impregnation with various blends of novel fiber modify-ing enzymes before chemical pretreatment and two stages of refining using the preconditioning refiner chemical–alkaline peroxide mechanical pulping (PRC-APMP) process. Wood chip impregnation and pulp processing was con-ducted at a pilot plant in the United States. When compared under constant chemical application and at a constant 350 mL CSF, enzyme treatment reduced specific refining energy by at least 24%. The effect of one versus two stages of impregnation and of enzyme action upon several physical pulp properties was determined.

Eucalyptus wood chips were impregnated with various blends of fiber modifying enzymes prior to preconditioning refiner chemical-alkaline peroxide mechanical pulp processing. The process includes chemical pretreatment and two stages of refining. The energy consumption was compared at the same Canadian standard freeness level of 350 ml. Some enzyme treatments were found to reduce specific refining energy (SRE) by at least 24%. The enzyme hydrolysis within the cell wall was observed by transmission electron microscopy of impregnated chips with high spatial resolution. The enzyme blends that successfully reduced SRE requirements were found to selectively loosen the bonds between the S1 and S2 layers of the fiber wall. Enzymes which selectively attached the S2 layer did not impart any SRE reduction. All experiments for impregnation and pulp processing were conducted at the Andritz Pilot Plant in Springfield, OH.

RTSTM is a new Low Retention, High Temperature and High Speed TMP pulping method developed by Andritz. While the pulp quality is kept the same as conventional TMP, the energy is 15-17% less than the conventional TMP.Extensive studies were conducted to evaluate the development of pine pulp properties and energy requirements using two different thermomechanical refining processes at a southern U. S. paper mill.The processes included both a low intensity (TMP) and a high intensity (RTSTM) refining configuration. The pulps produced with the RTS process had 15%-17% lower energy consumption compared to TMP pulps produced at similar freeness and handsheet physical properties. Despite similar average fiber length results between the two processes, the low intensity pulps had a higher percent by weight of fiber retained on the Bauer McNett 14/28 fractions, whereas the high intensity pulps had a higher percent by weight retained on the middle fractions. Calendered newsprint produced from the high intensity pulp had a lower roughness, which may be related to the lower fiber size distribution. Light was thrown on this finding by porometry measurements of the newsprint, which revealed a slightly lower pore size distribution from paper produced with the higher intensity pulp. Standard ink printing tests, however, provided similar results between newsprint paper produced from the TMP and RTSTM processes.

Background Early-onset scoliosis frequently leads to major thoracic deformity and pulmonary restrictive disease. Growing rods surgical techniques were developed to achieve a satisfactory correction of the spinal curves during growth. The effect on the rib cage deformity has not yet been documented. The purpose of this study was to analyze the changes of the thoracic geometry after implantation of a growing rod, and to evaluate a stereoradiographic reconstruction method among young scoliotic patients. Methods Four patients were enrolled in the study, and four additional patients in the reproducibility study. Three-dimensional spine and rib cage models were generated after low-dose stereoradiographic imaging (EOS). Three-dimensional parameters were computed before and after surgery. Intra and inter-observer reproducibility was calculated, and the accuracy was assessed in comparison to volumetric CT-scan. Findings The average Cobb angle was reduced from 50.8° to 26°. The surgery resulted in a complex 3D effect on the rib cage, combining frontal, lateral, and axial rotation. This effect was dependent of the side (concave or convex), and the position relative to the apical vertebra. Mean errors in comparison to CT-scan were 3.5 mm. Interpretation The results on the spinal deformity are comparable to other series. The effect on the rib cage is of a smaller magnitude than in the case of a spinal arthrodesis. A longer follow-up is necessary to confirm the positive effect on the rib cage deformity. Further research should be performed to improve the reproducibility of 3D parameters.

Introduction Les tumeurs malignes primitives osseuses interessant l’articulation sacro-iliaque sont de traitement difficile. Objectif Evaluer la procedure utilisee pour l’exerese de ces tumeurs et la reconstruction de la continuite de l’anneau pelvien, ainsi que le resultat carcinologique et les resultats fonctionnels. Materiels et Methodes Il s’agit d’une analyse retrospective continue des patients traites pour une tumeur de l’aile iliaque ou du sacrum envahissant la sacro-iliaque. Le grading tumoral repose sur la classification d’Enneking et les resultats fonctionnels sur le score MSTS. Resultats De 1986 a 2003, 24 patients ont presente une tumeur interessant la sacro-iliaque, 6 d’entre elles envahissaient le corps du sacrum. Il s’agissait de 8 osteosarcomes, 8 Ewing, 3 hystiocytofibromes malins, 2 osteosarcomes, 1 schwannome, un leiomyosarcome, et 1 hemangiopericytome. Dix-sept patients ont eu une chimiotherapie neo-adjuvante. L’intervention a ete realisee par une voie de crete elargie permettant d’avoir acces aux deux faces de l’anneau pelvien. Dans six cas, un sacrifice neurologique a ete necessaire. La duree operatoire moyenne etait de 5,27 heures. La reconstruction a ete effectuee par une autogreffe et une instrumentation. L’exerese etait qualifiee de large 11 fois, marginale 12 fois ou contaminee 1 fois. Le recul moyen etait de 4,77 ans. Dix patients sont decedes de leur maladie. La survie est liee a la qualite de l’exerese et au stade tumoral initial. La realisation d’une hemisacrectomie n’influence pas le pronostic vital. La consolidation osseuse a ete obtenue chez 13 patients, dont 10 sont survivants. Chez les 14 patients survivants au dernier recul, le score MSTS moyen est de 48 %. Les 9 n’ayant pas necessite de sacrifice neurologique avaient un score moyen de 58 % ; les 5 autres presentaient en revanche un score de 38 %. Ce score etait de 65 % en cas de consolidation, et de 8 % en cas de pseudarthrose. Discussion La survie des patients presentant une tumeur de l’articulation sacro-iliaque est avant tout liee a la nature histologique et a la qualite de l’exerese. La methode de reconstruction proposee permet, en cas de controle de la maladie, une consolidation et un resultat satisfaisant sur le plan fonctionnel quand il n’y a pas de sacrifice neurologique.

Background A novel, highly efficient deacetylation and disk refining (DDR) process to liberate fermentable sugars from biomass was recently developed at the National Renewable Energy Laboratory (NREL). The DDR process consists of a mild, dilute alkaline deacetylation step followed by low-energy-consumption disk refining. The DDR corn stover substrates achieved high process sugar conversion yields, at low to modest enzyme loadings, and also produced high sugar concentration syrups at high initial insoluble solid loadings. The sugar syrups derived from corn stover are highly fermentable due to low concentrations of fermentation inhibitors. The objective of this work is to evaluate the economic feasibility of the DDR process through a techno-economic analysis (TEA). Results A large array of experiments designed using a response surface methodology was carried out to investigate the two major cost-driven operational parameters of the novel DDR process: refining energy and enzyme loadings. The boundary conditions for refining energy (128–468 kWh/ODMT), cellulase (Novozyme’s CTec3) loading (11.6–28.4 mg total protein/g of cellulose), and hemicellulase (Novozyme’s HTec3) loading (0–5 mg total protein/g of cellulose) were chosen to cover the most commercially practical operating conditions. The sugar and ethanol yields were modeled with good adequacy, showing a positive linear correlation between those yields and refining energy and enzyme loadings. The ethanol yields ranged from 77 to 89 gallons/ODMT of corn stover. The minimum sugar selling price (MSSP) ranged from $0.191 to $0.212 per lb of 50 % concentrated monomeric sugars, while the minimum ethanol selling price (MESP) ranged from $2.24 to $2.54 per gallon of ethanol. Conclusions The DDR process concept is evaluated for economic feasibility through TEA. The MSSP and MESP of the DDR process falls within a range similar to that found with the deacetylation/dilute acid pretreatment process modeled in NREL’s 2011 design report. The DDR process is a much simpler process that requires less capital and maintenance costs when compared to conventional chemical pretreatments with pressure vessels. As a result, we feel the DDR process should be considered as an option for future biorefineries with great potential to be more cost-effective. Electronic supplementary material The online version of this article (doi:10.1186/s13068-015-0358-0) contains supplementary material, which is available to authorized users.

The contact mechanics that arise during bar-crossing impacts are responsible for inducing the stresses, and corresponding strains, that develop raw wood fibre into useful papermaking pulp. Enhancing our knowledge of the interactions that make up these impacts, and how they are affected by process variables, is therefore a necessary step to advancing refiner technology. Experiments by Senger and Ouellet [1] involving individual fibre bundles, or flocs, in a single-bar refiner have indicated that bar forces are dependent on floc consistency, floc grammage and bar edge sharpness. These results offered insight into previously unexplainable behavior, but investigation of these relationships in mill-scale refiners was restricted by lack of available measurement technology. This investigation is now possible with the development of a refiner force sensor (RFS) that replaces a small segment of refiner bar, and is capable of measuring normal and shear forces experienced during individual bar-crossing impacts. Bar forces from RFS tests in two mill-scale refiners under nominal operation have already been reported [2]. During the same installations, consistency within the refining zone was also varied in individual experiments. The principal goal of this work is to report on the effects of refining consistency on recorded bar forces in these two trials.