Inguinal hernia surgery : aspects on chronic pain and contralateral repair

Inguinal hernia is common, and the only permanent treatment is surgical repair. Approximately 16,000 hernia repairs are performed annually in Sweden. Optimized surgical technique including mesh prosthesis decreases the prevalence of recurrences and the main outcome measurement is today chronic postoperative inguinal pain (CPIP). CPIP prevalence is often reported as 10-30%. The wider use of endo-laparoscopic surgical technique has slightly decreased the prevalence of CPIP and has also offered the opportunity to perform a bilateral inguinal hernia repair, as well as exploration for occult hernias in the contralateral groin, during one procedure without additional incisions. Considering the large number of patients with CPIP it is vital to better understand the etiology and causes for the development of CPIP. It is also of interest to evaluate the benefits and risks to an extended laparoscopic procedure such as a bilateral prophylactic hernia repair. In Paper I, the aim was to explore if surgical postoperative complications increased the risk for CPIP in a long-term cohort study. Participants responded to the Inguinal Pain Questionnaire (IPQ) regarding postoperative groin pain 8 years after inguinal hernia repair. Responses to the questionnaire were matched with data regarding self-reported postoperative complications after open inguinal hernia repair. A total of 170 patients (17.9%) reported persistent groin pain and 29 patients (3.0%) reported severe persistent groin pain. Severe pain in the preoperative or immediate postoperative period was a significant risk factor while increasing age was negatively correlated to the risk for chronic groin pain. In Paper II, the aim was to develop and evaluate a condensed version of the IPQ. The IPQ is a standardized and validated instrument for assessing CPIP after groin hernia surgery. The Short- Form Inguinal Pain Questionnaire (sf-IPQ) comprises two main items extracted from the IPQ. Four hundred patients with groin hernia repairs were recruited from the Swedish Hernia Register (SHR) and were sent the IPQ, sf-IPQ and the Short-Form McGill Pain Questionnaire (SF-MPQ) three years after hernia repair. Correlation, consistency, and agreement were seen between the IPQ and sf-IPQ despite a systematic difference in level of pain score. The forms appeared to provide similar responses for parameters assessed by both instruments, though the sf-IPQ may be a more sensitive instrument. In Paper III, the aim was to analyze if specific postoperative complications constitute predictors for the risk of developing CPIP using a population-based prospective cohort of 30,659 patients operated for groin hernia 2015–2017 included in the SHR. Registered post-operative complications were categorized into hematomas, surgical site infections (SSI), seromas, urinary tract complications, and acute post-operative pain. A questionnaire enquiring about groin pain was distributed to all patients 1 year after surgery. Acute postoperative pain was a strong predictor for CPIP following both open anterior and endo-laparoscopic hernia repair. SSI and hematoma were predictors for CPIP following open anterior hernia repair. In Paper IV, the aim was to investigate the incidence as well as the factors predictive for a subsequent hernia repair on the contralateral side following a primary unilateral hernia repair. Participants were recruited from the SHR. 151,297 patients operated with a unilateral groin hernia repair using open and endo-laparoscopic technique, during 2007-2019, were studied. There were 7.4% registered contralateral hernia repairs with a median time to contralateral repair of 2.7 years. Significant predictors for a subsequent contralateral hernia were, male sex, high age, medial inguinal hernia, combined inguinal hernia, hernia defect size >1.5 cm, and a repair on the left side. Endo-laparoscopic repairs and obesity were associated with a lower incidence of a later contralateral repair. In conclusion, patient reported CPIP is a significant negative outcome following groin hernia repair that needs to be evaluated continuously. The sf-IPQ can be recommended as an evaluation tool in daily clinical practice. The postoperative complications: postoperative severe pain, hematomas, and SSI were associated with CPIP. These predictors may be related to surgical technique. Considering the relatively low incidence of subsequent contralateral hernia repairs, a routine extended exposure of the contralateral groin or a prophylactic contralateral repair cannot be recommended considering the risk for surgical complications and associated CPIP

Rotation Averaging and Strong Duality

In this paper we explore the role of duality principles within the problem of rotation averaging, a fundamental task in a wide range of computer vision applications. In its conventional form, rotation averaging is stated as a minimization over multiple rotation constraints. As these constraints are non-convex, this problem is generally considered challenging to solve globally. We show how to circumvent this difficulty through the use of Lagrangian duality. While such an approach is well-known it is normally not guaranteed to provide a tight relaxation. Based on spectral graph theory, we analytically prove that in many cases there is no duality gap unless the noise levels are severe. This allows us to obtain certifiably global solutions to a class of important non-convex problems in polynomial time. We also propose an efficient, scalable algorithm that out-performs general purpose numerical solvers and is able to handle the large problem instances commonly occurring in structure from motion settings. The potential of this proposed method is demonstrated on a number of different problems, consisting of both synthetic and real-world data

Potentials and limitations for the use of accessibility measures for national transport policy goals in freight transport and logistics: evidence from Västra Götaland County, Sweden

In Swedish national transport policy is freight transport regarded as a major facilitator for economic development on all geographical levels. At the same time it is noted that methods and data on business location and transportation is not adequate in order to follow-up transport policy objectives. This paper reports on a pilot study on the potential to develop accessibility measures to support and follow up policy objectives in Swedish context. The concept of accessibility and its practical use in concrete measures is discussed and problematized. A number of practical examples from Region Västra Götaland are used as illustrations. In terms of results the study identifies a number of potentials and limitations of using accessibility measures for freight transport issues. The usefulness is mainly driven by the integration capability of transport and land-use. This opens up for more complex questions and measures and thus supports the integration between planning specialisations. Limitations are to a large extent related to data availability and quality and to the degree of which models are possible to communicate to non-experts. The concluding discussion highlights how the policy and governance context is key in understanding how to best utilise the potential strengths of the accessibility concept and measures

Recent advances in preventing cardiovascular disorders by managing lipid levels

Advances in clinical lipidology during the last 18 months include the establishment of high-sensitivity C-reactive protein (hsCRP) as an important risk marker for cardiovascular disease. Determining hsCRP levels should help the clinician single out patients at particularly high risk. However, more research needs to be done in this area. Furthermore, statins do not seem to be of benefit in patients with severe congestive heart failure, on chronic hemodialysis, or with aortic stenosis. Next, plasma triglyceride levels are now considered an important risk marker for cardiovascular disease, but the therapeutic benefits related to lowering triglyceride levels remain difficult to achieve. Also, nicotinic acid has gained more interest partly because recent studies have demonstrated positive effects on atherosclerosis development and partly because the side effect of flushing seems to be partially avoidable with the concomitant administration of laropiprant. Both the raising of high-density lipoprotein cholesterol by nicotinic acid and the additional lowering of low-density lipoprotein cholesterol by ezetimibe and eprotirome will need to demonstrate hard endpoint reductions in large-scale intervention trials. Trials of niacin/laropiprant (the AIM-HIGH and HPS2-THRIVE studies) and ezetimibe (the IMPROVE-IT study) are already under way

Active Damping of a Flexible Beam

This paper describes the active damping of a flexible beamconnected to the end-effector of a robot manipulator. An observer-basedfeedback controller is developed and experimental results arepresented. Iterative feedback tuning (IFT) is applied to shape the step response

On the current-voltage relationship in auroral breakups and westwards-travelling surges

International audienceAuroral precipitating electrons pass through an acceleration region before entering the atmosphere. Regardless of what produces it, a parallel electric field is assumed to cause the acceleration. It is well known that from kinetic theory an expression for the corresponding upward field-aligned current can be calculated, which under certain assumptions can be linearized to j?=KV. The K constant, referred to as the Lyons-Evans-Lundin constant, depends on the source density and thermal energy of the magnetospheric electrons; it is an important parameter in magnetosphere-ionosphere coupling models. However, the K parameter is still rather unknown, and values are found in a wide range of 10?8?10?10 S m?2. In this study, we investigated how the type of auroral structure affects the K values. We look at onset and westwards-travelling surge (WTS) events and make comparisons with earlier results from observations of more stable auroral arcs. A new analysis technique for studying those magnetospheric parameters using ground-based measurements is introduced. Electron density measurements are taken with the EISCAT radar, and through an inversion technique the flux-energy spectra are calculated. Source densities, thermal energies and potential drops are estimated from fittings of accelerated Maxwellian distributions. With this radar technique we have the possibility to study the changes of the mentioned parameters during the development of onsets and the passage of surges over EISCAT. The study indicates that the linearization of the full Knight formulation holds even for the very high potential drops and thermal temperatures found in the dynamic onset and WTS events. The values of K are found to be very low, around 10?11 S m?2 in onset cases as well as WTS events. The results may establish a new technique where ionospheric measurements are used for studying the ionosphere-magnetosphere coupling processes

Termofotonisten laitteiden valmistus ja karakterisointi

Tässä diplomityössä tutkitaan termofotonisille laitteille tarkoitettujen LED-rakenteiden valmistusta ja karakterisointia. Termofotonisen laitteen toiminta perustuu elektroluminesenssijäähdytykseen, eli LEDin kykyyn emittoida fotoneja, jotka ovat saanet osan energiastaan hilalämmöstä. Ilmiö saattaa mahdollistaa LEDin jäähtymisen sen emittoidessa valoa, jos häviöt ovat riittävän pieniä. Työn teoreettisessa osassa käsitellään lyhyesti LEDien ja metallikontaktien perusominaisuuksia. Metallikontakteja käytetään injektoimaan virtaa ja heijastamaan valoa rakenteissa. Valmistusprosessi alkaa indiumfosfidi (InP) puolijohdesubstraatista, jonka pinnalle kasvatetaan useita puolijohdekerroksia, ml. aktiivinen InGaAs-kerros, tavoitteena saada aikaan valoa emittoiva p-n-liitos. Sähköiset kontaktit valmistetaan höyrystämällä metallia puolijohderakenteiden pinnalle. Valmistetut rakenteet karakterisoidaan fotoluminesenssimittauksilla (PL), virtajännitemittauksilla (I-V) ja atomivoimamikroskoopilla (AFM). Näytteitä valmistettiin työn aikana 63 kpl, joista 22 oli valmiita InP/InGaAs p-n-liitos LED-rakenteita joiden PL-huiput sijoittuivat välille 1630 - 1690 nm.In this thesis, the fabrication properties and characterization of broad area light emitting LED structures for thermo photonic devices are studied. The operation of a thermo photonic device is based on electroluminescent cooling, i.e. the ability of an LED to emit photons that have received a part of their energy from the lattice heat. This phenomenon allows an LED to cool down as it emits light if other losses are sufficiently small. The theoretical part of the work briefly reviews the basic properties of light-emitting diodes and metal contacts used to inject current and to reflect light in the structures. The fabrication process starts with indium phosphide (InP) semiconductor wafers, on which several semiconductor layers are grown, including an InGaAs active layer, in order to create a p-n junction capable of emitting light. Electrical contacts are made by evaporating metal on the semiconductor structures. The structures fabricated are characterized by photoluminescence (PL) measurements, then by current-voltage (I-V) measurements and also by atomic force microscopy (AFM) which was also briefly reviewed in this work. Of the 63 fabricated samples 22 were complete InP/InGaAs p-n junction LED structures whose PL peaks were in the range 1630 - 1690 nm

Gunnar Björling: Ord och att ej annat

Gunnar Björling: Ord och att ej anna