Absence Of Instability Research Articles

Multiple Level Anterior Cervical Discectomy and Fusion with PEEK Cage without Plating: Clinical Outcomes

Abstract Background: Anterior cervical discectomy and fusion is a common procedure done to treat cervical disk disease. The role of plating in the treatment of multilevel disc disease in the absence of instability has been debated with some claiming no difference in the clinical outcomes. Objective: The aim of the study was to assess the long term clinical outcomes of patients who underwent two or three level discectomies with PEEK cage placement without plating. Material and Methods: We collected the required data of all patients. Patients were contacted and completed clinical outcome questionnaires including NDI and VAS-Neck. All data was tabulated and statistical analysis was done. Results: Data of 72 patients was collected. The average age of the patients was 52.73 years. The mean follow-up was 62.4 months. 37 patients presented with Myelopathy (51%), 24 with radiculopathy (33%), 11 with myeloradiculopathy. The average VAS scores for neck pain preoperatively was 6.29 (Range: 4–9) and postoperatively improved to an average of 3.18 (Range: 0–7). The average neck disability index preoperatively was 37.86 (Range: 28–47) and the average postoperative NDI score being 19.02 (Range: 9 to 28). Our patients had a preoperative mean mJOA score of 11.68 (Range:3–17) and a mean postoperative mJOA score of 14.66 (3–17) with a mean difference of 3 points. Conclusion: The clinical outcomes of multiple-level cervical fusion without plating and with plating are similar. The best surgical option is one that requires minimal disruption of normal tissue, simple in technique and provides the patient with immediate- and long-term relief.

Landiolol for Treatment of New-Onset Atrial Fibrillation in Critical Care: A Systematic Review.

Background: new-onset atrial fibrillation remains a common complication in critical care settings, often necessitating treatment when the correction of triggers is insufficient to restore hemodynamics. The treatment strategy includes electric cardioversion in cases of hemodynamic instability and either rhythm control or rate control in the absence of instability. Landiolol, an ultrashort beta-blocker, effectively controls heart rate with the potential to regulate rhythm. Objectives This review aims to compare the efficacy of landiolol in controlling heart rate and converting to sinus rhythm in the critical care setting. Methods: We conducted a comprehensive review of the published literature from 2000 to 2022 describing the use of landiolol to treat atrial fibrillation in critical care settings, excluding both cardiac surgery and medical cardiac care settings. The primary outcome assessed was sinus conversion following landiolol treatment. Results: Our analysis identified 17 publications detailing the use of landiolol for the treatment of 324 critical care patients. While the quality of the data was generally low, primarily comprising non-comparative studies, landiolol consistently demonstrated similar efficacy in controlling heart rate and facilitating conversion to sinus rhythm in both non-surgical (75.7%) and surgical (70.1%) settings. The incidence of hypotension associated with landiolol use was 13%. Conclusions: The use of landiolol in critical care patients with new-onset atrial fibrillation exhibited comparable efficacy and tolerance in both non-surgical and surgical settings. Despite these promising results, further validation through randomized controlled trials is necessary.

Analysis of economic and mathematical models of monetary stimulation for the development of smart industry

Abstract The article considers economic and mathematical models in the context of monetary stimulation of financial and economic development of the smart industry. The article analyses AD-AS, DSGE, VAR, CAPM, RBC, Phillips Curve and Cobb-Douglas models. The advantages and disadvantages of the models in the context of monetary stimulation of smart industry development are identified. The analysis has revealed that all the considered models have certain disadvantages, such as complexity of use and lack of clarity in interpreting the results, as well as limited consideration of factors that are important in monetary stimulation of the smart industry. The reviewed VAR model is limited in taking into account all factors affecting economic variables and is sensitive to specification, which leads to significant changes in the final results depending on the included variables and their specification. The CAPM model is based on assumptions about market efficiency that do not always correspond to reality, while the RBC model is characterised by the absence of instability and unrealistic assumptions about market behaviour. The Phillips Curve model shows instability when inflation and unemployment respond to economic shocks in different ways, which is unacceptable in the context of monetary stimulation for the development of the smart industry. The analysis identified the advantages and disadvantages of all models, which allowed us to objectively assess the actual conditions of the models. The analysis has shown that, given the above shortcomings and the specifics of the current economic environment, the Cobb-Douglas model is the most effective for analysing and forecasting the development of the smart industry in Ukraine. The other models considered may also be useful for stimulating the development of the smart industry, but they do not provide the same flexibility and ease of use as the Cobb-Douglas model. Thus, given the specifics of monetary policy, the Cobb-Douglas model seems to be the most appropriate tool for analysing and forecasting monetary stimulus for the development of the smart industry in Ukraine. It allows for a wide range of production factors and is simple to analyse and interpret the final results, making it the most suitable for addressing complex issues of monetary stimulation in the context of smart industry development. Keywords monetary stimulation, smart industry, development, modeling

Detailed mass transfer studies of a ternary system associated with intermittent jerking of the liquid − liquid interface

Experiments were carried out to transfer diethylamine (DEA) from water to carbon tetrachloride under static conditions inside a 50 cm3 buret for the fixed initial concentration of 2.5 mol dm−3. Initial concentration was chosen after ruling out lower concentrations to study the long-term instability. The phase volumes (i.e., 5 and 10 cm3) were equal for the separate trials at different extraction times. During extraction, intermittent interfacial jerking occurred up to 1800 s. After this time, the jerking frequency decreased and disappeared by 3600 s. The jerking time interval increased as the extraction progressed. Jerking resulted in profuse streaming into the extract phase, coupled with a throw of liquid from the interfacial region to the bulk of the aqueous phase. The complete concentration profiles of the solute in both phases were developed immediately after the jerking phenomena. In the aqueous phase, the concentration profiles revealed one and two zones of the minimum concentration of DEA in the bulk of the 5- and 10-cm3 phase volumes, respectively. The interfacial mass transfer coefficient during the jerking was high due to the absence of any interfacial barrier. The interfacial mass transfer coefficient in the absence of instability was much less than that in the presence of jerking. Also, it was higher than that for the systems where unidirectional ejections occurred due to the energy instability of the liquid–liquid interface. This work has also estimated the average spreading velocity of the interface, which caused the jerking due to the obstruction from the wall.

Detachment forces during parallel-plate gap separation mediated by a simple yield-stress fluid.

In this work we have monitored the multiple stages of the normal traction force response of a yield-stress fluid confined between two circular parallel plates that are separated at constant velocity. At narrow initial gaps, the air-fluid interface suffers from the Saffman-Taylor instability, confirmed by visual inspection of fingering patterns imprinted on the fluid. At larger initial gaps, the fluid preserves the initially imposed circular symmetry of the confining plates, indicating the absence of instability. Due to the system characteristics and experimental environment, the multiple traction force contributions occurred in cascade, permitting us to isolate the adhesion responses associated with viscosity, capillarity, and yield stress. Employing a standard Herschel-Bulkley model, we assessed the scaling of the traction force in multiple regimes-specifically, evaluating the dependencies of the fingering to yield-stress transitions.

Cholinergic system correlates of postural control changes in Parkinson's disease freezers.

Postural instability and freezing of gait are the most debilitating dopamine-refractory motor impairments in advanced stages of Parkinson's disease because of increased risk of falls and poorer quality of life. Recent findings suggest an inability to efficaciously utilize vestibular information during static posturography among people with Parkinson's disease who exhibit freezing of gait, with associated changes in cholinergic system integrity as assessed by vesicular acetylcholine transporter PET. There is a lack of adequate understanding of how postural control varies as a function of available sensory information in patients with Parkinson's disease with freezing of gait. The goal of this cross-sectional study was to examine cerebral cholinergic system changes that associate with inter-sensory postural control processing features as assessed by dynamic computerized posturography and acetylcholinesterase PET. Seventy-five participants with Parkinson's disease, 16 of whom exhibited freezing of gait, underwent computerized posturography on the NeuroCom© Equitest sensory organization test platform, striatal dopamine, and acetylcholinesterase PET scanning. Findings demonstrated that patients with Parkinson's disease with freezing of gait have greater difficulty maintaining balance in the absence of reliable proprioceptive cues as compared to those without freezing of gait [β = 0.28 (0.021, 0.54), P = 0.034], an effect that was independent of disease severity [β = 0.16 (0.062, 0.26), P < 0.01] and age [β = 0.092 (-0.005, 0.19), P = 0.062]. Exploratory voxel-based analysis revealed an association between postural control and right hemispheric cholinergic network related to visual-vestibular integration and self-motion perception. High anti-cholinergic burden predicted postural control impairment in a manner dependent on right hemispheric cortical cholinergic integrity [β = 0.34 (0.065, 0.61), P < 0.01]. Our findings advance the perspective that cortical cholinergic system might play a role in supporting postural control after nigro-striatal dopaminergic losses in Parkinson's disease. Failure of cortex-dependent visual-vestibular integration may impair detection of postural instability in absence of reliable proprioceptive cues. Better understanding of how the cholinergic system plays a role in this process may augur novel treatments and therapeutic interventions to ameliorate debilitating symptoms in patients with advanced Parkinson's disease.

Decompression and Interlaminar Stabilization for Lumbar Spinal Stenosis: A Cohort Study and Two-Dimensional Operative Video.

Background and Objectives: Lumbar spinal stenosis is one of the most common causes of disability in the elderly and often necessitates surgical intervention in patients over the age of 65. Our study aimed to evaluate the clinical efficacy of interlaminar stabilization following decompressive laminectomy in patients with lumbar stenosis without instability. Materials and Methods: Twenty patients with lumbar stenosis underwent decompressive laminectomy and interlaminar stabilization at our academic institution. Clinical outcomes were measured using the visual analog scale (VAS) and Oswestry disability index (ODI) at the 2-month, 6-month, and 1-year postoperative visits, and these outcomes were compared to the preoperative scores. Results: The average VAS scores for low back pain significantly improved from 8.8 preoperatively to 4.0, 3.7, and 3.9 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). The average VAS scores for lower extremity pain significantly improved from 9.0 preoperatively to 2.7, 2.5, and 2.5 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). The average ODI scores significantly improved from 66.6 preoperatively to 23.8, 23.3, and 24.5 at 2 months, 6 months, and 1 year postoperatively, respectively (p < 0.001). There was no statistical significance for difference in VAS or ODI scores between 2 months, 6 months, and 1 year. One patient had an intraoperative durotomy that was successfully treated with local repair and lumbar drainage. Another patient had progression of stenosis and had to undergo bilateral facetectomy and fusion. Conclusions: Decompressive laminectomy and interlaminar stabilization in patients with spinal claudication and low back pain is a good surgical option in the absence of instability and may provide significant clinical improvement of pain and functional disability.

Anterior Transcorporeal Approach for Cervical Metastatic Melanoma Resection Guided by O-Arm–Navigated Intraoperative Computed Tomography

Surgical resection of the ventrally located tumor in the cervical spinal region is technically challenging and usually requires a traditional extensive approach. To reduce collateral injury and preserve cervical stability, the anterior transcorporeal approach under navigated guidance is an alternative minimally invasive technique. To describe a minimally invasive transcorporeal approach for cervical intradural extramedullary tumor resection and spinal cord decompression. Previous literature regarding available treatment options was reviewed. A patient with known intracranial malignant melanoma presented with severe myelopathy from metastatic melanoma compressing the cervical cord. The anterior transcorporeal approach for total tumor resection and spinal cord decompression under a microscope was planned. Under spinal navigation, small bone tunneling was performed to expose and remove the tumor without compromising cervical stability. The melanoma resection was successfully performed without complications. Myelopathic symptoms were significantly improved with the absence of instability or local recurrence at the long-term follow-up. We present the anterior transcorporeal approach that can be used to resect the tumor in the ventral cervical region and effectively decompress the cervical cord without complications. Moreover, this approach is the minimally invasive surgical technique that preserves spinal stability, minimizes bleeding, and shortens the hospital stay.

A lógica Interna do squash e as aprendizagens do jogo

Introdução: A pesquisa é oriunda de uma parceria entre grupos de pesquisa que investigam o jogo como linguagem subjetiva e que possui uma gramática singular de análise ancorada pela Praxiologia Motriz, criada por Pierre Parlebas. Objetivo: Analisar as possíveis aprendizagens da prática do squash a partir de sua lógica interna. Metodologia: Trata-se de uma análise praxiológica, com ênfase na lógica interna tendo em vista a descrição da essência desse jogo esportivo. A metodologia é de abordagem qualitativa, com caráter descritivo, embasada pela Praxiologia Motriz (PM). Resultados e discussão: De acordo com a PM, o squash pode ser classificado como um jogo sociomotriz com presença de adversário e ausência de companheiro (1x1) ou presença de companheiro e adversário (2x2) e ausência de instabilidade e incerteza quanto ao entorno físico. A partir dos resultados desta pesquisa evidenciamos que a PM oferece subsídios para um rol de possibilidades de aprendizagens na prática do squash. Considerações Finais: As aprendizagens geradas pelas interações entre jogadores, espaços e implementos favoreceram um maior conhecimento das ações motrizes desenvolvidas nas situações do squash, o que contribuiu em informações analíticas para alunos e professores que atuam com o esporte.

Aortic dissection extending from the brachiocephalic artery during transradial coronary catheterization: a case report

BackgroundIatrogenic acute aortic dissection (AD) is an extremely rare but devastating complication during cardiac catheterization. It can be treated conservatively if it develops in a retrograde form or manifests as an intramural hematoma (IMH) with a micro-intimal tear in the absence of instability. However, only a few reports exist on its natural course and long-term outcomes.Case presentationA 78-year-old woman presented to the emergency department with acute chest discomfort. Elective cardiac catheterization was performed via the right radial artery. The patient’s brachiocephalic artery was so tortuous that the hydrophilic soft guidewire had to be exchanged for a stiffer one. However, the stiff wire caused the dissection of a tortuous brachiocephalic artery that extended from the sinuses of Valsalva to the proximal descending aorta. Emergent computed tomography showed crescentic aortic wall thickening without a dissection flap. The patient had cardiac tamponade and a gradually thickening thrombosed false lumen. Although the patient was unstable during the first 2 weeks, she was stabilized during hospital stay with only conservative treatment. Consequently, she has been well for over 5 years.ConclusionsEven though the patient showed ominous findings, a good prognosis was expected because the AD was mainly retrograde. Furthermore, the thrombosed false lumen mimicked an IMH on imaging. To the best of our knowledge, this is the first report of an extensive iatrogenic AD originating from the brachiocephalic artery during right transradial catheterization that was treated conservatively despite clinical instability.

Development and External Validation of a Novel Clinical Score to Quantify the Presence of Instability Characteristics in Patients with Borderline Acetabular Dysplasia

Objectives:Treatment of borderline acetabular dysplasia is controversial. The existing literature lacks direct comparisons of different treatment approaches and focuses on lateral center edge angle (LCEA), failing to account for other important diagnostic characteristics. The purpose of this study was (1) to determine the most important characteristics in determining hip instability in this population, and (2) to develop a nomogram for clinical use and calculation of the Borderline Hip Instability Score (BHIS), and (3) to externally validate the BHIS in a multicenter prospective cohort of patients with borderline acetabular dysplasia.Methods:The current study included two parts. In Part 1, this study utilized a retrospective cohort study of 186 hips (178 patients) undergoing surgical treatment in setting of borderline acetabular dysplasia (LCEA 20°-25°) from a single surgeon experienced in arthroscopic and open techniques. Patients were excluded if over 40 years of age, Tonnis grade ≥2, prior ipsilateral surgery, or residual pediatric or neuromuscular disease. Multivariate analysis determined characteristics associated with presence of instability (treated with PAO +/- hip arthroscopy) or absence of instability (treated with isolated hip arthroscopy) based on clinical diagnosis of the single surgeon. During the study period, 39.8% of the cohort underwent PAO. Multivariate analysis with bootstrapping was performed and results were transformed into a nomogram and BHIS (higher score representing more instability). In Part 2, the BHIS was externally validated in a cohort of 114 patients with borderline acetabular dysplasia enrolled in a multicenter prospective cohort study across 10 other surgeons (with varied treatment approaches from arthroscopy to open procedures).Results:In Part 1, the most parsimonious and best fit model included 4 variables associated with instability: acetabular inclination (AI), anterior center edge angle (ACEA), maximum alpha angle, and internal rotation in 90 degrees of flexion (IRF). Odds ratio estimates and 95% confidence limits were 1.50 (1.28-1.76), 0.92 (0.86-0.99), 0.94 (0.90-0.98), and 1.11 (1.07-1.17), respectively. Notably, sex and LCEA were not significant predictors. The BHIS demonstrated excellent predictive (discriminatory) ability with c-statistic=0.89. Mean BHIS in the population was 50.0 (instability 57.7 ±7.9 vs. non-instability 44.8±7.3, p<0.001). BHIS demonstrated excellent predictive (discriminatory) ability with c-statistic=0.89. In Part 2, BHIS maintained excellent c-statistic=0.92 in external validation. Mean BHIS in this cohort was 53.9 (instability 66.5±11.5 vs. non-instability 43.0±10.8, p<0.001).Conclusion:In patients with borderline acetabular dysplasia, AI, ACEA, maximum alpha angle, and IRF were key factors in diagnosing significant instability treated with PAO. The BHIS effectively quantifies relative role of each factor and characterizes aspects of instability compared to the mean (BHIS=50) in this population. The BHIS score allowed for good differentiation of patients with and without instability in the development cohort, as well as the external validation cohort. Use of the BHIS score may facilitate efficient clinical characterization of important patient characteristics in the setting of borderline acetabular dysplasia.

PATIENTS FOCUS ON PERFORMANCE OF PHYSICAL ACTIVITY, KNEE STABILITY AND ADVICE FROM CLINICIANS WHEN MAKING DECISIONS CONCERNING THE TREATMENT OF THEIR ANTERIOR CRUCIATE LIGAMENT INJURY

When deciding medical treatment, patients' perspectives are important. There is limited knowledge about patients' views when choosing non-operative treatment or anterior cruciate ligament (ACL) reconstruction (ACLR) after ACL injury. To describe reasons that influenced patients' decisions for non-operative treatment or ACLR after ACL injury. Cross-sectional study. This study recruited a total of 223 patients (50% men), aged 28 ± 8 years who had sustained ACL injury, either unilateral or bilateral. Subjects were, at different time points after injury, asked to fill out a questionnaire about their choice of treatment, where an ACLR treatment decision was made, some responded before and some after the ACLR treatment. A rating of the strength of 10 predetermined reasons in their choice of treatment graded as 0 (no reason) to 3 (very strong reason), was done. Patients with unilateral ACL injury treated with ACLR (110 patients) rated "inability to perform physical activity at the same level as before the injury due to impaired knee function" (96%), "fear of increased symptoms during activity" (87%) and "giving way episodes" (83%) as strong or very strong reasons in their treatment decision. Patients with bilateral ACL injury treated with ACLR (109 knees) rated similar reasons as patients with unilateral ACLR and also "low confidence in the ability to perform at the preinjury activity level without ACLR" (80%) as strong or very strong reasons. Patients with unilateral ACL injury treated non-operatively (46 patients) rated "advice from clinician" (69%) as a strong or very strong reason. Patients with bilateral ACL injury treated non-operatively (25 knees) rated "absence of giving way episodes" (62%), and "no feeling of instability" (62%) as strong or very strong reasons. Inability to perform physical activity, fear of increased symptoms, and giving way episodes were reasons that patients with ACL injury considered when making decisions about ACLR. When choosing non-operative treatment, patients considered the absence of instability or giving way symptoms, being able to perform physical activity, and advice from clinicians. 4.

Chronic Posttraumatic Instability of the Distal Radioulnar Joint: Foveal Reattachment of the Triangular Fibrocartilage Complex With Dorsal Capsuloplasty and Extensor Retinaculum Imbrications.

Background: The purpose of this article is to describe the surgical technique used by the authors and the outcome in the treatment of chronic posttraumatic instability of the distal radioulnar joint (DRUJ). Methods: A retrospective study was conducted analyzing the medical records of 11 patients with chronic posttraumatic instability of the DRUJ, treated by a foveal reattachment of the triangular fibrocartilage complex with dorsal capsular and extensor retinaculum imbrications between 2016 and 2017, with a follow-up evaluation of 1 year. Results: All patients reported pain relief and the absence of instability, returning to normal activities in 3 to 6 months. Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire ranged from 2 to 25, resulting in a mean score of 9.5. Forearm rotation averaged 89° of pronation and 85° of supination. Conclusion: Foveal reattachment of the triangular fibrocartilage complex with dorsal capsular and extensor retinaculum imbrications is an effective surgical procedure for the treatment of DRUJ chronic posttraumatic instability.

DEVELOPMENT AND EXTERNAL VALIDATION OF A NOVEL CLINICAL SCORE TO QUANTIFY THE PRESENCE OF INSTABILITY CHARACTERISTICS IN PATIENTS WITH BORDERLINE ACETABULAR DYSPLASIA

BackgroundTreatment of borderline acetabular dysplasia (BD) is controversial with some patients having primarily instability-based symptoms while others have impingement-based symptoms. The existing literature lacks direct comparisons of different treatment approaches, and generally fails to report other important diagnostic characteristics beyond the lateral center edge angle (LCEA).PurposeThe purpose of this study was (1) to identify the most important patient characteristics influencing the diagnosis of instability vs. non-instability, (2) to develop a clinical score (Borderline Hip Instability Score, BHIS) to collectively characterize these factors and (3) to externally validate BHIS in a multicenter cohort BD patients.MethodsIn Part 1, this study utilized a retrospective cohort study of 186 hips undergoing surgical treatment of BD (LCEA 20°-25°) from a single surgeon experienced in arthroscopic and open techniques. Multivariate analysis determined characteristics associated with presence of instability (treated with PAO +/- hip arthroscopy) or absence of instability (treated with isolated hip arthroscopy) based on clinical diagnosis of the single surgeon. During the study period, 39.8% of the cohort underwent PAO. Multivariate analysis with bootstrapping was performed and results were transformed into a BHIS nomogram (higher score representing more instability). In Part 2, BHIS was externally validated in 114 BD patients enrolled in a multicenter prospective cohort study across 10 surgeons (with varied treatment approaches from arthroscopy to open procedures).ResultsIn Part 1, the most parsimonious, best fit model included 4 variables associated with the diagnosis of instability: acetabular inclination (AI), anterior center edge angle (ACEA), maximum alpha angle, and internal rotation in 90 degrees of flexion (IRF). Sex and LCEA were not significant predictors. Mean BHIS in the population was 50.0 (instability 57.7 ±7.9; non-instability 44.8±7.3, p<0.001). BHIS demonstrated excellent predictive (discriminatory) ability with c-statistic=0.89. In Part 2, BHIS maintained excellent c-statistic=0.92 in external validation. Mean BHIS in the external cohort was 53.9 (instability 66.5±11.5; non-instability 43.0±10.8, p<0.001).DiscussionIn patients with BD, key factors in diagnosing significant instability treated with PAO were AI, ACEA, maximum alpha angle, and IRF. The BHIS score allowed for differentiation of patients with and without instability in the development and external validation cohort.

Stand-alone polyetheretherketone cages for anterior cervical discectomy and fusion for successive four-level degenerative disc disease without plate fixation.

Background:Anterior cervical discectomy with fusion became the most frequently performed technique for the treatment of symptoms related to cervical disc prolapse. Multilevel anterior cervical discectomy has been combined with anterior cervical plate application to help maintain the cervical lordosis and enhance fusion. This was associated with more soft-tissue separation and retraction with increased incidence of surgically related complications and postoperative dysphagia.Aim of the Study:The aim of this study is to evaluate the safety and efficacy of the stand-alone cervical polyetheretherketone (PEEK) cages in four-level discectomy and to determine if it is possible to avoid anterior plate fixation and to achieve satisfactory outcomes.Methodology:This is a retrospective study which was performed between June 2011 and December 2018 at one institute. The clinical and radiological data were collected from patients who underwent successive four-level anterior cervical discectomy and fusion with PEEK cages for degenerative cervical disc disease without plate fixation.Results:This study included 66 patients, 35 males and 31 females. The follow-up period was 24 months. Mean Japanese Orthopedic Association scores were 13.3 ± 1.41 preoperative and 15.9 ± 0.86 postoperative (P = 0.046). The cervical curvature index “Ishihara” (ICI) was 9.9 ± 5.90 preoperative and the mean of ICI was 10.5 ± 6.65 postoperative, which is insignificant, P = 0.7). The lordotic curvature according to these results was preserved till the end of the year and half of the follow-up period postoperative.Conclusion:Consecutive four-level anterior discectomy with PEEK cage interbody fusion without plate and screw is a safe and effective procedure in the absence of instability, and it may be a reliable alternative for the treatment of multilevel cervical disc.

Comparing clinical outcomes of repeat discectomy versus fusion for recurrent disc herniation utilizing the N2QOD

OBJECTIVE Recurrent lumbar disc herniation (RLDH) is a significant cause of morbidity in patients undergoing lumbar discectomy and has been reported to occur in up to 18% of cases. While repeat discectomy is often successful in treating these patients, concern over repeat RLDH may lead surgeons to advocate instrumented fusion even in the absence of instability. The authors' goal was to compare clinical outcomes for patients undergoing repeat discectomy versus instrumented fusion for RLDH. METHODS The authors used the National Neurosurgery Quality and Outcomes Database (N2QOD) to assess outcomes of patients who underwent repeat discectomy versus instrumented fusion at a single institution from 2012 to 2015. Primary outcomes included Oswestry Disability Index (ODI) score, visual analog scale (VAS) score, and quality-adjusted life year (QALY) measures. Secondary outcomes included hospital length of stay, discharge status, and hospital charges. RESULTS The authors identified 25 repeat discectomy and 12 instrumented fusion patients with 3- and 12-month follow-up records. The groups had similar ODI and VAS scores and QALY measurements at 3 and 12 months. Patients in the instrumented fusion group had significantly longer hospitalizations (3.7 days vs 1.0 days, p < 0.001) and operative times (229.6 minutes vs 82.7 minutes, p < 0.001). They were also more likely to be female (p = 0.020) and to be discharged to inpatient rehabilitation instead of home (p = 0.036). Hospital charges for the instrumented fusion group were also significantly higher ($54,458.29 vs $11,567.05, p < 0.001). Rates of reoperation were higher in the repeat discectomy group (12% vs 0%), but the difference was not statistically significant (p = 0.211). CONCLUSIONS Repeat discectomy and instrumented fusion result in similar clinical outcomes at short-term follow-up. Patients undergoing repeat discectomy had significantly shorter operative times and length of stay, and they incurred dramatically lower hospital charges. They were also less likely to require acute rehabilitation postoperatively. Further research is needed to compare these two management strategies.

On the resonance amplification of magnetic perturbations near the threshold of tearing instability in a tokamak

Using a cylindrical model, a relatively simple description is presented of how a magnetic field perturbation stimulated by a low external helical current or a small helical distortion of the boundary and generating magnetic islands penetrates into a plasma column with a magnetic surface q=m/n to which tearing instability is attached. Linear analysis of the classical instability with an aperiodic growth of the perturbation in time shows that the perturbation amplitude in plasma increases in a resonant manner as the discharge parameters approach the threshold of tearing instability. In a stationary case, under the assumption on the helical character of equilibrium, which can be found from the two-dimensional nonlinear equation for the helical flux, there is no requirement for the small size of the island. Examples of calculations in which magnetic islands are large near the threshold of tearing instability are presented. The bifurcation of equilibrium near the threshold of tearing instability in plasma with a cylindrical boundary, i.e., the existence of helical equilibrium (along with cylindrical equilibrium) with large islands, is described. Moreover, helical equilibrium can also exist in the absence of instability.

How do revised shoulders that are culture positive for Propionibacterium differ from those that are not?

Many shoulder arthroplasties revised for pain, stiffness, or component loosening are culture positive for Propionibacterium. The culture results are unknown until days or weeks after surgery, too late to inform intraoperative surgical decisions and immediate postsurgical antibiotic treatment. The objective of this study was to identify preoperative and intraoperative characteristics that may alert surgeons to an increased likelihood of positive cultures. We analyzed the records of 132 shoulders that underwent surgical revision of a shoulder arthroplasty, 66 of which became culture positive for Propionibacterium and 66 did not. Propionibacterium-positive and Propionibacterium-negative shoulders were similar with respect to many characteristics; however, Propionibacterium-negative shoulders were revised sooner after the index procedure and were significantly more likely to be female, to have sustained a fall, to have instability, and to have rotator cuff deficiency. Intraoperatively, Propionibacterium-positive shoulders demonstrated more glenoid erosions, glenoid osteolysis, glenoid loosening, and a higher incidence of a soft tissue membrane between the humeral component and humeral endosteum. Shoulders culture positive for Propionibacterium were more likely to be culture positive for another bacteria. Although Propionibacterium-positive and Propionibacterium-negative shoulders have many similarities, factors such as male gender, delayed presentation, glenoid osteolysis and loosening, humeral membrane, and the absence of instability or cuff failure should arouse suspicion of Propionibacterium and suggest the need for deep cultures and consideration of aggressive surgical and medical treatment.

TITANINIAI IMPLANTAI GYDANT KRŪTINĖS NESTABILUMĄ; PIRMOJI PATIRTIS LIETUVOJE

Sternal nonunion as a result of cardiac intervention or trauma remains a morbid condition with serious sequelae. Patients often report pain with breathing, coughing, and/or movement. The authors present two patients that were diagnosed with sterile nonunion after cardiac procedure (1) or trauma (1). The cardiac patient presented after 48 months after his cardiac procedure; trauma patient presented 24 months after the accident.Diagnosis was made based on the clinical triad of sternal instability, pain, and absence of infection. Management with open stabilisation using titanium implants (Strasbourg Thorax Osteosyntheses System-STRATOS, MedXpert GmbH, Heitersheim, Germany) was performed in both patients. This was the first experience, using such implants in Lithuania. There was no incidence of subsequent infection. Pain previously due to chest instability completely resolved in both patients. The bone healing was assessed clinically with the absence of instability and pain and follow-up chest radiographs.

Triple decomposition technique in air–water flows: Application to instationary flows on a stepped spillway

Self-sustained instabilities and pseudo-periodic motion may be observed in hydraulic structures and industrial flows. Documented examples include the hydraulic jump, sloshing motion in a reservoir and surging waves in pooled stepped spillways. The instabilities may generate some very large turbulence levels and integral turbulent scales, combining the contributions of both slow fluctuations and fast turbulent fluctuations. Herein a triple decomposition of phase-detection probe signals was developed to identify the turbulent contributions of the slow and fast velocity components in highly aerated free-surface flows. The raw probe signals were split into slow and fast signal components and the air–water flow properties of each component were calculated. The method was applied to a new data set collected down a stepped spillway channel with two stepped configurations (flat and pooled). The latter configuration experienced some self-sustained pseudo-periodic instabilities. The data analysis results showed that the fast turbulent velocity fluctuations of the decomposed signal were close to the turbulence levels on the flat stepped spillway (i.e. in absence of instability). And the largest turbulent energy was contained in the slow fluctuating velocity component. The findings showed a new implementation of a triple decomposition technique to instationary air–water flows.