Acute disc herniation following surgical decompression of lumbar spinal stenosis: a retrospective comparison of mini-open and minimally invasive techniques.

BACKGROUND: Disc herniation following decompression of lumbar spinal stenosis is a less familiar surgical complication. Previous studies suggested that open lumbar decompression techniques, associated with relative segmental instability especially in the presence of degenerated disc in older patients, are more likely to result in disc herniation compared to minimally invasive techniques. The current study compares the incidence of acute disc herniation following mini-open and minimally invasive decompression of lumbar spinal stenosis. METHODS: This was a retrospective study reviewing 563 patients who underwent spinal decompression for symptomatic lumbar stenosis by mini-open bilateral partial laminectomy technique or minimally invasive laminotomy utilizing a tubular system. Demographic and clinical data were collected and compared between the groups. RESULTS: Postoperative disc herniation rate was significantly lower in the minimally invasive group with 2 of 237 cases (0.8%) versus 19 of 326 cases (5.8%) in the mini-open group (p = 0.002). This finding was more noticeable following multi-level procedures with no case of postdecompression disc herniation in the minimally invasive group compared to 8 of 39 cases (20.5%) in the mini-open group (p = 0.003). CONCLUSION: The incidence of postoperative disc herniation following spinal decompression for symptomatic lumbar stenosis was 5.8% following mini-open bilateral partial laminectomy compared to only 0.8% after minimally invasive laminotomy (p = 0.002). These findings highlight the more extensive nature of mini-open surgery associated with relative segmental instability that poses a greater risk for postoperative disc herniation.

Phase transition in the cuprates from a magnetic-field-free stiffness meter viewpoint.

A method to measure the superconducting (SC) stiffness tensor [Formula: see text], without subjecting the sample to external magnetic field, is applied to La1.875Sr0.125CuO4. The method is based on the London equation [Formula: see text], where J is the current density and A is the vector potential which is applied in the SC state. Using rotor free A and measuring J via the magnetic moment of superconducting rings, [Formula: see text] at T → Tc is extracted. The technique is sensitive to very small stiffnesses (penetration depths on the order of a few millimeters). The method is applied to two different rings: one with the current running only in the CuO2 planes, and another where the current must cross planes. We find different transition temperatures for the two rings, namely, there is a temperature range with two-dimensional stiffness. Additional low energy muon spin rotation measurements on the same sample determine the stiffness anisotropy at T < Tc.

The role of physical status versus mental status in predicting the quality of life of patients with lumbar disk herniation.

PURPOSE: To explore the role of physical status versus mental status in predicting the quality of life (QOL) of patients with lumbar disk herniation (LDH). METHOD: In this correlative study 51 patients with LDH were recruited in their conservative stage of treatment. After profiling their physical status, all participants reported about pain level (according to VAS), pain perception using the Pain Catastrophizing Scale (PCS), and disability level (according to Oswestry Low Back Pain Disability Questionnaire). Their mental status was evaluated using the Spielberger's State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI-II). Their QOL was evaluated by the World Health Organization Quality of Life Questionnaire, brief version (WHOQOL-BREF). RESULTS: Physical status/disability level correlated with anxiety and depression. While Physical status predicted physical QOL, mental status, and mainly anxiety and depression were the significant predictors of psychological, social, and environmental QOL. CONCLUSIONS: Mental status may play a significant role in reducing most QOL domains among patients with LDH. The evaluation and intervention process should consider both physical and mental status and their relation to the person's QOL. Since QOL is a major parameter in determining intervention type and success this elaborated perspective may contribute to the intervention planning and outcomes. Implications for rehabilitaion A significant mental distress may accompany the physical disability of patients with LDH. The role of this mental distress in reducing the QOL of patients with LDH may be greater than that of their physical disability. The evaluation and intervention for patients with LDH should refer to both physical and mental status and explore their impacts on quality of life in order to elevate intervention success.

[Lumbar nucleoplasty].

Low back pain (LBP) is one of the common reasons for people to seek treatment from a physician. A familiar cause of LBP and radicular pain is disc bulge or protrusion. The treatment for this indication is diverse and suited to the type pathology and its severity. The treatment can be conservative ranging from a diversity of minimal invasive surgical methods to an open discectomy. The classification of disc herniation is based on the severity of the bulge, whereby the lowest degree is protrusion/ prolapse, then extrusion and the most severe level is sequestered disc. This classification is important when considering the treatment options. One of the known possible treatments for disc protrusion is Nucleoplasty or disc Coblation. This percutaneous surgical method is used to treat discogenic back pain and radicular pain. This method is based on reducing disc volume by using radio frequency energy. During the last decade, many medical centers worldwide used this procedure. In recent years, this method is rising in popuLarity due to its percutaneous approach, low complication rate, good results at the post surgical stage reflecting improvement in symptoms and facilitating rapid return to normal life. The accepted indications for Nucleoplastia are discogenic radicular pain, contained disc herniation according to an MRI scan with intact annulus fibrosus, insufficient response to conservative treatment and absence of a medical emergency as in the case of Cauda Equina syndrome. Patient selection according to those parameters is very important. Today this surgical method is still controversial. In recent years many studies regarding Nucleoplasty have been published, although more research is necessary in order to evaluate long term results and tailor it to the appropriate patient and pathology.

Short-lived charge-transfer excitons in organic photovoltaic cells studied by high-field magneto-photocurrent.

The main route of charge photogeneration in efficient organic photovoltaic cells based on bulk hetero-junction donor-acceptor blends involves short-lived charge-transfer excitons at the donor-acceptor interfaces. The cell efficiency is critically affected by the charge-transfer exciton recombination and dissociation processes. By measuring the magneto-photocurrent under ambient conditions at room temperature, we show here that magnetic field-induced spin-mixing among the charge-transfer exciton spin sublevels occurs in fields up to at least 8.5 Tesla. The resulting magneto-photocurrent increases at high fields showing non-saturating behaviour up to the highest applied field. We attribute the observed high-field spin-mixing mechanism to the difference in the donor-acceptor g-factors. The non-saturating magneto-photocurrent response at high field indicates that there exist charge-transfer excitons with lifetime in the sub-nanosecond time domain. The non-Lorentzian high-field magneto-photocurrent response indicates a dispersive decay mechanism that originates due to a broad distribution of charge-transfer exciton lifetimes.

Comprehensive study of the spin-charge interplay in antiferromagnetic La(2-x)Sr(x)CuO4.

The origin of the pseudogap and its relationship with superconductivity in the cuprates remains vague. In particular, the interplay between the pseudogap and magnetism is mysterious. Here we investigate the newly discovered nodal gap in hole-doped cuprates using a combination of three experimental techniques applied to one, custom made, single crystal. The crystal is an antiferromagnetic La(2-x)Sr(x)CuO4. with x=1.92%. We perform angle-resolved photoemission spectroscopy measurements as a function of temperature and find: quasi-particle peaks, Fermi surface, anti-nodal gap and below 45 K a nodal gap. Muon spin rotation measurements ensure that the sample is indeed antiferromagnetic and that the doping is close, but below, the spin-glass phase boundary. We also perform elastic neutron scattering measurements and determine the thermal evolution of the commensurate and incommensurate magnetic order, where we find that a nodal gap opens well below the commensurate ordering at 140 K, and close to the incommensurate spin density wave ordering temperature of 30 K.

[Sport activity after hip and knee arthroplasty].

Joint arthroplasty is one of the commonest surgical procedures in orthopedic surgery. In recent years there was an increase in the number of procedures, patient satisfaction and implant survival. Originally, these operations were designed for old patients in order to relieve pain and to enable ambulation. Over the past few years, these operations have become common in younger patients which desire to return to activity, including sports activities. The importance of physical activity is a well known fact. In recent years it became clear that with the proper physical activity the outcomes of the operations are better. There are several types of arthroplasty. Many factors influence the outcome of the operation apart from the post-surgery physical activity. These factors include patient factors, surgical technique and type of arthroplasty. This review summarizes the recommendations for sports activities after hip and knee arthroplasties. These activities are evaluated according to surgeons' recommendations, stress applied on the implant and long term outcomes. The recommended sports activities after joint arthroplasties are walking, swimming and cycling. Soccer, basketball and jogging are not advised. Tennis, downhill skiing and horse riding are recommended with previous experience. There are many more sports activities that patients can participate in, and it is important that the patient discuss the different options prior to the operation. Since these operations are so common, many non-orthopedic physicians encounter these patients in their practice. They should be acquainted with the recommendations for sports activities and encourage them.

The Herbertsmithite Hamiltonian: µSR measurements on single crystals.

We present transverse field muon spin rotation/relaxation measurements on single crystals of the spin-1/2 kagome antiferromagnet Herbertsmithite. We find that the spins are more easily polarized when the field is perpendicular to the kagome plane. We demonstrate that the difference in magnetization between the different directions cannot be accounted for by Dzyaloshinskii-Moriya-type interactions alone and that anisotropic axial interaction is present.

Attention-deficit hyperactivity disorder in children with benign epilepsy and their siblings.

This prospective study explores the prevalence and characteristics of attention-deficit hyperactivity disorder in children with benign epilepsy, compared with its prevalence in their siblings. Among 40 patients with benign epilepsy, 28 (70%) were diagnosed with attention-deficit hyperactivity disorder: 19 with the inattentive type, one with the hyperactive type, and eight with the combined type. In the control group of 12 siblings, only two (16.7%) were diagnosed with attention-deficit hyperactivity disorder (P<0.03). A trend toward an increased risk for attentional difficulties was evident in children whose seizures were more resistant and required more than one antiepileptic drug for seizure control. Children with more epileptiform features in their electroencephalograms were also more subject to signs of attention deficit hyperactivity disorder. Larger scale studies are required to validate our findings.

Experimental estimates of dephasing time in molecular magnets.

Muon spin relaxation measurements in isotropic molecular magnets (MM) with a spin value S ranging from 7/2 to 27/2 are used to determine the magnitude and origin of dephasing time tau(phi) of molecular magnets. It is found that tau(phi) approximately 10 nsec with no S or ligand dependence. This indicates a nuclear origin for the stochastic field. Since tau(phi) is a property of the environment, we argue that it is a number common to similar types of MM. Therefore, tau(phi) is shorter than the Zener and tunneling times of anisotropic MM such as Fe(8) or Mn(4) for standard laboratory sweep rates. Our findings call for a stochastic Landau-Zener theory in this particular case.

Quest for frustration driven distortion in Y2(Mo2)O(7).

We investigated the nature of the freezing in the geometrically frustrated Heisenberg spin glass Y2(Mo2)O(7) by measuring the temperature dependence of the static internal magnetic field distribution above the spin-glass temperature, Tg, using the muon spin relaxation technique. The evolution of the field distribution cannot be explained by changes in the spin susceptibility alone and suggests a lattice deformation. This possibility is addressed by numerical simulations of the Heisenberg Hamiltonian with magnetoelastic coupling at T > 0.

Pure nuclear quadrupole resonance determination of the electric field gradient asymmetry for broad lines.

We present an angle dependent nuclear quadrupole resonance (ADNQR) method to determine the electric field gradient asymmetry parameter eta in systems where the resonance line is so broad that the radio frequency field can excite only a portion of the nuclear spins. In this situation, the recently developed spectroscopic methods are not applicable. ADNQR is useful for single crystals and oriented powders, and, for small eta determines eta4. Therefore, it can be used to evaluate fluctuations in eta due to inhomogeneities. We demonstrate the application of ADNQR experimentally to oriented superconducting YBa2Cu3O7 powder.

Dynamical crossover in an Ising spin glass above T(g): a muon-spin-relaxation investigation of Fe0.05TiS2.

We investigate the temperature dependence of the spin-spin dynamical autocorrelation function of the Ising spin glass Fe0.05TiS2 through field dependent muon-spin lattice relaxation measurements. We successfully analyze the results using the Ogielski function, namely, t(-x)exp((-[t/tau](y)) as employed in numerical simulations. The experimental estimates of x, y, and tau are compared with those from simulations. Our major finding is that in this system the correlation function changes its nature from Ogielski to a form indistinguishable from pure stretched exponential upon cooling close to T(g), indicating a dynamical crossover.

Common energy scale for magnetism and superconductivity in underdoped cuprates: a muon spin resonance investigation of (Ca(x)La(1-x)) (Ba(1.75-x)La(0.25+x))Cu3O(y).

We characterize the spontaneous magnetic field, and determine the associated temperature T(g), in the superconducting state of (Ca(x)La(1-x)) (Ba(1.75-x)La(0.25+x)) Cu(3)O(y) using zero and longitudinal field muon spin resonance measurements for various values of x and y. Our major findings are (i) T(g) and T(c) are controlled by the same energy scale, (ii) the phase separation between hole poor and hole rich regions is a microscopic one, and (iii) spontaneous magnetic fields appear gradually with no moment size evolution.