Long-term results of obstetric brachial plexus surgery

Background: Brachial plexus birth palsy (BPBP) most often occurs as a result of foetal-maternal disproportion. The C5 and C6 nerve roots of the brachial plexus are most frequently affected. In contrast, roots from the C7 to Th1 that result in total injury together with C5 and C6 injury, are affected in fewer than half of the patients. BPBP was first described by Smellie in 1764. Erb published his classical description of the injury in 1874 and his name became linked with the paralysis that is associated with upper root injury. Since then, early results of brachial plexus surgery have been reasonably well documented. However, from a clinical point of view not all primary results are maintained and there is also a need for later follow-up results. In addition most of the studies that are published emanate from highly specialized clinics and no nation wide epidemiological reports are available. One of the plexus injuries is the avulsion type, in which the nerve root or roots are ruptured at the neural cord. It has been speculated whether this might cause injury to the whole neural system or whether shoulder asymmetry and upper limb inequality results in postural deformities of the spine. Alternatively, avulsion could manifest as other signs and symptoms of the whole musculoskeletal system. In addition, there is no available information covering activities of daily living after obstetric brachial plexus surgery. Patients and methods: This was a population-based cross-sectional study on all patients who had undergone brachial plexus surgery with at least 5 years of follow-up. An incidence of 3.05/1000 for BPBP was obtained from the registers for this study period. A total of 1706 BPBP patients needing hospital treatment out of 1 717 057 newborns were registered in Finland between 1971 and 1997 inclusive. Of these BPBP patients, 124 (7.3%) underwent brachial plexus surgery at a mean age of 2.8 months (range: 0.4―13.2 months). Surgery was most often performed by direct neuroraphy after neuroma resection (53%). Depending on the phase of the study, 105 to 112 patients (85-90%) participated in a clinical and radiological follow-up assessment. The mean follow up time exceeded 13 years (range: 5.0―31.5 years). Functional status of the upper extremity was evaluated using Mallet, Gilbert and Raimondi scales. Isometric strength of the upper limb, sensation of the hand and stereognosis were evaluated for both the affected and unaffected sides then the differences and their ratios were calculated and recorded. In addition to the upper extremity, assessment of the spine and lower extremities were performed. Activities of daily living (ADL), participation in normal physical activities, and the use of physiotherapy and occupational therapy were recorded in a questionnaire. Results: The unaffected limb functioned as the dominant hand in all, except four patients. The mean length of the affected upper limb was 6 cm (range: 1-13.5 cm) shorter in 106 (95%) patients. Shoulder function was recorded as a mean Mallet score of 3 (range: 2―4) which was moderate. Both elbow function and hand function were good. The mean Gilbert elbow scale value was 3 (range: -1―5) and the mean Raimondi hand scale was 4 (range:1―5). One-third of the patients experienced pain in the affected limb including all those patients (n=9) who had clavicular non-union resulting from surgery. A total of 61 patients (57%) had an active shoulder external rotation of less than 0° and an active elbow extension deficiency was noted in 82 patients (77%) giving a mean of 26° (range: 5°―80°). In all, expect two patients, shoulder external rotation strength at a mean ratio 35% (range: 0―83%) and in all patients elbow flexion strength at a mean ratio of 41% (range: 0―79%) were impaired compared to the unaffected side. According to radiographs, incongruence of the glenohumeral joint was noted in 15 (16%) patients, whereas incongruence of the radiohumeral joint was found in 20 (21%) patients. Fine sensation was normal for 34/49 (69%) patients with C5-6 injury, for 15/31 (48%) with C5-7 and for only 8/25 (32%) of patients with total injury. Loss of protective sensation or absent sensation was noted in some palmar areas of the hand for 12/105 patients (11%). Normal stereognosis was recorded for 88/105 patients (84%). No significant inequalities in leg length were found and the incidence of structural scoliosis (1.7%) did not differ from that of the reference population. Nearly half of the patients (43%) had asynchronous motion of the upper limbs during gait, which was associated with impaired upper limb function. Data obtained from the completed questionnaires indicated that two thirds (63%) of the patients were satisfied with the functional outcome of the affected hand although one third of all patients needed help with ADL. Only a few patients were unable to participate in physical activities such as: bicycling, cross-country skiing or swimming. However, 71% of the patients reported problems related to the affected upper limb, such as muscle weakness and/or joint stiffness during the aforementioned activities. Incongruity of the radiohumeral joints, extent of the injury, avulsion type injury, age less than three months of age at the time of plexus surgery and inexperience of the surgeon was related to poor results as determined by multivariate analyses. Conclusions: Most of the patients had persistent sequelae, especially of shoulder function. Almost all measurements for the total injury group were poorer compared with those of the C5-6 type injury group. Most of the patients had asymmetry of the shoulder region and a shorter affected upper limb, which is a probable reason for having an abnormal gait. However, BPBP did not have an effect on normal growth of the lower extremities or the spine. Although, participation in physical activities was similar to that of the normal population, two-thirds of the patients reported problems. One-third of the patients needed help with ADL. During the period covered by this study, 7.3% BPBP of patients that needed hospital treatment had a brachial plexus operation, which amounts to fewer than 10 operations per year in Finland. It seems that better results of obstetric plexus surgery and more careful follow-up including opportunities for late reconstructive procedures will be expected, if the treatment is solely concentrated on by a few specialised teams.

Adaptive tree multigrids and simplified spherical harmonics approximation in deterministic neutral and charged particle transport

A new deterministic three-dimensional neutral and charged particle transport code, MultiTrans, has been developed. In the novel approach, the adaptive tree multigrid technique is used in conjunction with simplified spherical harmonics approximation of the Boltzmann transport equation. The development of the new radiation transport code started in the framework of the Finnish boron neutron capture therapy (BNCT) project. Since the application of the MultiTrans code to BNCT dose planning problems, the testing and development of the MultiTrans code has continued in conventional radiotherapy and reactor physics applications. In this thesis, an overview of different numerical radiation transport methods is first given. Special features of the simplified spherical harmonics method and the adaptive tree multigrid technique are then reviewed. The usefulness of the new MultiTrans code has been indicated by verifying and validating the code performance for different types of neutral and charged particle transport problems, reported in separate publications.

The relationships between work stressors and organizational performance in long-term care for elderly residents

This study investigates the relationships between work stressors and organizational performance in terms of the quality of care provided by the long-term care facilities. Work stressors are first examined in relation to the unit's structural factors, resident characteristics, and to the unit specialization. The study is completed by an investigation into the associations of work stressors such as job demands or time pressure, role ambiguity, resident-related stress, and procedural injustice to organizational performance. Also the moderating effect of job control in the job demands organizational performance relationship is examined. The study was carried out in the National Research and Development Centre for Welfare and Health (STAKES). Survey data were drawn from 1194 nursing employees in 107 residential-home and health-center inpatient units in 1999 and from 977 employees in 91 units in 2002. Information on the unit resident characteristics and the quality of care was provided by the Resident Assessment Instrument (RAI). The results showed that large unit size or lower staffing levels were not consistently related to work stressors, whereas the impairments in residents' physical functioning in particular initiated stressful working conditions for employees. However, unit specialization into dementia and psychiatric residents was found to buffer the effects that the resident characteristics had on employee appraisals of work stressors, in that a high proportion of behavioral problems was related to less time pressure and role conflicts for employees in specialized units. Unit specialization was also related to improved team climates and the organizational commitment of employees. Work stressors associated with problems in care quality. Time pressure explained most of the differences between units in how the employees perceived the quality of physical and psychosocial care they provide for the residents. A high level of job demands in the unit was also found to be related to some increases in all clinical quality problems. High job control buffered the effects of job demands on the quality of care in terms of the use of restraints on elderly residents. Physical restraint and especially antipsychotic drug use were less prevalent in units that combined both high job demands and high control for employees. In contrast, in high strain units where heavy job demands coincided with a lack of control for employees, quality was poor in terms of the frequent use of physical restraints. In addition, procedural injustice was related to the frequent use of antianxiety of hypnotic drugs for elderly residents. The results suggest that both job control and procedural justice may have improved employees' abilities to cope when caring for the elderly residents, resulting in better organizational performance.

Coherent quasiparticle approximation cQPA and nonlocal coherence

We show that the dynamical Wigner functions for noninteracting fermions and bosons can have complex singularity structures with a number of new solutions accompanying the usual mass-shell dispersion relations. These new shell solutions are shown to encode the information of the quantum coherence between particles and antiparticles, left and right moving chiral states and/or between different flavour states. Analogously to the usual derivation of the Boltzmann equation, we impose this extended phase space structure on the full interacting theory. This extension of the quasiparticle approximation gives rise to a self-consistent equation of motion for a density matrix that combines the quantum mechanical coherence evolution with a well defined collision integral giving rise to decoherence. Several applications of the method are given, for example to the coherent particle production, electroweak baryogenesis and study of decoherence and thermalization.

Finnish Short-Term Stock Returns

Functioning capital markets are a crucial part of a competitive economy since they provide the mechanisms to allocate resources. In order to be well functioning a capital market has to be efficient. Market efficiency is defined as a market where prices at any time fully reflect all available information. Basically, this means that abnormal returns cannot be predicted since they are dependent on future, presently unknown, information. The debate of market efficiency has been going on for several decades. Most academics today would probably agree that financial markets are reasonably efficient since virtually nobody has been able to achieve continuous abnormal positive returns. However, it is clear that a set of return anomalies exists, although they are apparently to small to enable substantial economic profit. Moreover, these anomalies can often be attributed to market design. The motivation for this work is to expand the knowledge of short-term trading patterns and to offer some explanations for these patterns. In the first essay the return pattern during the day is examined. On average stock prices move during two time periods of the day, namely, immediately after the opening and around the formal close of the market. Since stock prices, on average, move upwards these abnormal returns are generally positive and cause the distinct U-shape of intraday returns. In the second essay the results in the first essay are examined further. The return pattern around the former close is shown to partly be the result of manipulative action by market participants. In the third essay the focus is shifted towards trading patterns of the underlying stocks on days when index options and index futures on the stocks expire. Generally no expiration day effect was found. However, some indication of an expiration day effect was found when a large amount of open in- or at-the-money contracts existed. Also, the effects were likelier to be found for shares with high index-weight but fairly low trading volume. Last, in the forth essay the attention is turned to the behaviour of different tax clienteles around the dividend ex-day. Two groups of investors showed abnormal trading behaviour. Domestic non-financial investors, especially domestic companies, showed a dividend capturing behaviour, i.e. buying cum-dividend and selling ex-dividend shares. The opposite behaviour was found for foreign investors and domestic financial institutions. The effect was more notable for high yield, high volume stocks.

Short-term Price Behavior and the Effect of Foreign Investors in Finnish Equity Markets (summary section only)

As globalization and capital free movement has increased, so has interest in the effects of that global money flow, especially during financial crises. The concern has been that large global money flows will affect the pricing of small local markets by causing, in particular, overreaction. The purpose of this thesis is to contribute to the body of work concerning short-term under- and overreaction and the short-term effects of foreign investment flow in the small Finnish equity markets. This thesis also compares foreign execution return to domestic execution return. This study’s results indicate that short-term under- and overreaction occurs in domestic-buy portfolios (domestic net buying) rather than in foreign-buy portfolios. This under- and overreaction, however, is not economically meaningful after controlling for the bid-ask bounce effect. Based on this finding, one can conclude that foreign investors do not have a destabilizing effect in the short-term in the Finnish markets. Foreign activity affects short-term returns. When foreign investors are net buyers (sellers) there are positive (negative) market adjusted returns. Literature related to nationality and institutional effect leads us to expect these kind of results. These foreign flows are persistent at a 5 % to 21 % level and the persistence of foreign buy flow is higher than the foreign sell flow. Foreign daily trading execution is worse than domestic execution. Literature which quantifies foreign investors as liquidity demanders and literature related to front-running leads us to expect poorer foreign execution than domestic execution.

Owners' Way or the Highway: Short-term Expectations and Owner Impatience

Increased media exposure to layoffs and corporate quarterly financial reporting have created arguable a common perception – especially favored by the media itself – that the companies have been forced to improve their financial performance from quarter to quarter. Academically the relevant question is whether the companies themselves feel that they are exposed to short-term pressure to perform even if it means that they have to compromise company’s long-term future. This paper studies this issue using results from a survey conducted among the 500 largest companies in Finland. The results show that companies in general feel moderate short-term pressure, with reasonable dispersion across firms. There seems to be a link between the degree of pressure felt, and the firm’s ownership structure, i.e. we find support for the existence of short-term versus long-term owners. We also find significant ownership related differences, in line with expectations, in how such short-term pressure is reflected in actual decision variables such as the investment criteria used.

Embracing Integrability in Stellar and Planetary Dynamics

Hamiltonian systems in stellar and planetary dynamics are typically near integrable. For example, Solar System planets are almost in two-body orbits, and in simulations of the Galaxy, the orbits of stars seem regular. For such systems, sophisticated numerical methods can be developed through integrable approximations. Following this theme, we discuss three distinct problems. We start by considering numerical integration techniques for planetary systems. Perturbation methods (that utilize the integrability of the two-body motion) are preferred over conventional "blind" integration schemes. We introduce perturbation methods formulated with Cartesian variables. In our numerical comparisons, these are superior to their conventional counterparts, but, by definition, lack the energy-preserving properties of symplectic integrators. However, they are exceptionally well suited for relatively short-term integrations in which moderately high positional accuracy is required. The next exercise falls into the category of stability questions in solar systems. Traditionally, the interest has been on the orbital stability of planets, which have been quantified, e.g., by Liapunov exponents. We offer a complementary aspect by considering the protective effect that massive gas giants, like Jupiter, can offer to Earth-like planets inside the habitable zone of a planetary system. Our method produces a single quantity, called the escape rate, which characterizes the system of giant planets. We obtain some interesting results by computing escape rates for the Solar System. Galaxy modelling is our third and final topic. Because of the sheer number of stars (about 10^11 in Milky Way) galaxies are often modelled as smooth potentials hosting distributions of stars. Unfortunately, only a handful of suitable potentials are integrable (harmonic oscillator, isochrone and Stäckel potential). This severely limits the possibilities of finding an integrable approximation for an observed galaxy. A solution to this problem is torus construction; a method for numerically creating a foliation of invariant phase-space tori corresponding to a given target Hamiltonian. Canonically, the invariant tori are constructed by deforming the tori of some existing integrable toy Hamiltonian. Our contribution is to demonstrate how this can be accomplished by using a Stäckel toy Hamiltonian in ellipsoidal coordinates.

Mid-urethral slings for treatment of stress urinary incontinence : long- and mid-term follow-up

Urinary incontinence is a common problem, affecting one third of the women at least at some time during their lives. The prevalence of urinary incontinence increases with advancing age, and the everyday impact of incontinence on women and on health services is enormous. Urinary incontinence is usually divided into three different subtypes, of which stress urinary incontinence (SUI) is the most common. Surgical treatment is often needed to cure SUI, and modern mid-urethral sling procedures give the possibility to cure this condition with a low risk of adverse events, a problem often associated with the so-called traditional incontinence operations. Life expectancy among women in Western countries has grown beyond 80 years of age. Long-term efficacy of treatment options for urinary incontinence therefore becomes an important issue in a world with limited eco-nomic resources. The purpose of the present study was to prospectively evaluate the long-term efficacy and safety of the first minimally invasive mid-urethral tape procedure, the Tension-free Vaginal Tape (TVT) procedure. The long-term (5-year) follow-up results of the TVT procedure as a repeat operation af-ter an unsuccessful mid-urethral tape operation were studied and the reasons for failure of the first operation were analyzed. Another purpose was to compare the original TVT procedure with a newer modification, the Tension-free Vaginal Tape Obturator (TVT-O) procedure within a multi-centre, randomized context in order to find out possible differences between these procedures re-garding efficacy and complications and the effects on symptoms of urgency. The first study of the present thesis is a prospective, Nordic, three-centre follow-up study of 90 women suffering from SUI, who were treated by means of the TVT procedure. The mean follow-up time was more than eleven years, and the study is the first to be published in connection with more than ten years of follow-up. The second study is a retrospective analysis of 26 women who were treated with a repeat TVT procedure after an unsuccessful primary mid-urethral tape procedure. The third and fourth studies concern 273 women in seven centres in Finland who were ran-domly assigned to the TVT and TVT-O procedures, the 3-year follow-up results of which are pre-sented in this thesis. After eleven years of follow-up, 90% of the women had a negative cough stress test result and a negative 24-h pad test result. The subjective cure rate measured as the women s global impression of cure was 77%, the rate of improvement 20%, and only 3% thought that the treatment had failed. No late-onset adverse effects were found. The repeat TVT procedure was successful in 75% of the cases when women who were cured and women who were significantly improved were included. The reasons for failure of the first operation could be separated into four different groups: tape material-related, operation technique-related, concomitant illness-related and a group with no identifiable reason. There were no intra-operative complications during the repeat operation. In the randomized trial comparing the TVT with the TVT-O procedure a cough stress test results were negative in 94.6% and 89.5% of the women in the two groups, respectively, after a 3-year follow-up period. There were no statistical differences in the cure rate or the rate of complications be-tween the two procedures. Symptoms of urgency were analyzed more closely and the main finding was that the prevalence of urgency symptoms decreased significantly after both mid-urethral sling procedures. The TVT operation was found to be an effective and safe procedure even after eleven years of follow-up. Long-term follow-up after a repeat TVT procedure revealed that the TVT procedure can well be considered after an unsuccessful mid-urethra tape procedure, because 75% of the patients showed significantly improvement of their incontinence. The TVT and TVT-O procedures showed no statistically significant differences in efficacy and rate of complications after three years of follow-up. In most cases these procedures alleviate preoperative symptoms of urgency and the risk of developing de novo urgency is low.

Fast distributed approximation algorithms for vertex cover and set cover in anonymous networks

We present a distributed algorithm that finds a maximal edge packing in O(Δ + log* W) synchronous communication rounds in a weighted graph, independent of the number of nodes in the network; here Δ is the maximum degree of the graph and W is the maximum weight. As a direct application, we have a distributed 2-approximation algorithm for minimum-weight vertex cover, with the same running time. We also show how to find an f-approximation of minimum-weight set cover in O(f2k2 + fk log* W) rounds; here k is the maximum size of a subset in the set cover instance, f is the maximum frequency of an element, and W is the maximum weight of a subset. The algorithms are deterministic, and they can be applied in anonymous networks.

A local 2-approximation algorithm for the vertex cover problem

We present a distributed 2-approximation algorithm for the minimum vertex cover problem. The algorithm is deterministic, and it runs in (Δ + 1)2 synchronous communication rounds, where Δ is the maximum degree of the graph. For Δ = 3, we give a 2-approximation algorithm also for the weighted version of the problem.

A simple local 3-approximation algorithm for vertex cover

We present a local algorithm (constant-time distributed algorithm) for finding a 3-approximate vertex cover in bounded-degree graphs. The algorithm is deterministic, and no auxiliary information besides port numbering is required. (c) 2009 Elsevier B.V. All rights reserved.