Intermittent cauda equina compression. An experimental study of the porcine cauda equina with analyses of nerve impulse conduction properties.

Study Design: Neurophysiologic reactions of cauda equina nerve roots to intermittently applied compression were assessed for two different modes of compression using a porcine model.

Objective: To assess the neurophysiologic reactions of cauda equina nerve roots to intermittently applied compression.

Summary Of Background Data: A number of experimental studies have been presented recently regarding the reaction pattern of spinal nerve roots to compression.

Evaluation of Boneloc. Chemical and mechanical properties, and a randomized clinical study of 30 total hip arthroplasties.

We evaluated the mechanical, chemical and clinical properties of Boneloc cement using radiostereometry and a series of laboratory tests. Compared to a standard cement (Palacos) the new cement displayed reduced tensile strength, elastic modulus, curing and glass transition temperatures. The amount of MMA extracted during 3 weeks in methanol was smaller for the Boneloc, but the total amount of released monomers was larger.

Early active mobilization of tendon grafts using mesh reinforced suture techniques.

The flexor digitorum profundus tendon in 11 digits with division of both flexor tendons in zone 2 was reconstructed with a palmaris longus tendon graft in a two-stage procedure. The distal and proximal fixation of the graft was reinforced with a polyester mesh sleeve placed around the ends of the graft during stage 1. All digits were mobilized with a combination of active extension and active and passive flexion within 3 days of the second stage.

Early active mobilization after tendon transfers using mesh reinforced suture techniques.

23 tendon transfers in the hand and forearm were performed using a polyester mesh sleeve to reinforce conventional suture techniques. All transfers were mobilized with active flexion and extension within 3 days of operation. Excluding one rupture (due to extreme unintentional loading) and depending on the type of transfer used, a mean of between 69% and 78% of the final active range of motion was obtained 1 month post-operatively.

Resonant frequency of a pin-accelerometer system mounted in bone.

Invasive measurements of spinal motion using intraosseous metal pins have become common. For this reason, the resonant frequency of intraosseous pins attached with accelerometers was determined using two different methods. It was concluded that plucking the pin is a reliable method for determining the resonant frequency and, in order to accurately measure bone movement at frequencies up to 32 Hz, the pin diameter should be 2.

Inflammatogenic properties of nucleus pulposus.

Study Design: The inflammatogenic properties of nucleus pulposus were assessed in two experimental models previously used for screening of inflammatogenic properties of other substances. This study was performed to assess the inflammatogenic properties of nucleus pulposus in models previously screened for other substances.

Summary Of Background Data: Previous experimental studies, as well as clinical observations, have indicated that inflammatory mechanisms may constitute an important pathogenetic component in sciatica due to herniation of the nucleus pulposus.

Neuropeptide changes in compressed spinal nerve roots.

Study Design: Compression-induced changes in the concentration of substance P and VIP (vasoactive intestinal polypeptide), in spinal nerve roots and dorsal root ganglia were studied in an experimental nerve root compression model in pigs.

Objectives: To analyze by radioimmunoassay the concentration of the neuropeptides substance P and VIP in a model for experimental chronic nerve root compression.

Summary Of Background Data: Neuropeptides such as substance P and VIP seem to be involved in the transmission of pain and changes in the levels of these neuropeptides have been described in models where peripheral or spinal nerve injury was induced.

Errors in determination of total body protein by in vivo neutron activation of nitrogen due to non-uniform neutron fluence inside the patient.

Total body protein can be estimated by in vivo neutron activation of nitrogen. The method is based on capture of thermal neutrons in a 14N(n,g )15N reaction. Sources of error associated with this method, such as background subtraction, variations in detection efficiency, etc, are analysed.

Experimental instability in the lumbar spine.

Study Design: An in vivo animal model of lumbar segmental instability, involving both passive and active stabilizing components of the spine, was developed.

Objective: The aim of this investigation was to dynamically study the alterations in segmental kinematics as a result of interventions to the passive stabilizing components and to the lumbar musculature.

Summary Of Background Data: Segmental instability in the lumbar spine is associated with abnormal intervertebral motion.

Cerebral dysfunction in fibromyalgia: evidence from regional cerebral blood flow measurements, otoneurological tests and cerebrospinal fluid analysis.

Measurements of regional cerebral blood flow (rCBF), analysis of cerebrospinal fluid, auditory brain stem responses (ABR) and oculomotor tests were performed in 19 patients with fibromyalgia. The results from the rCBF measurements showed a normal flow level with slight but significant focal flow decreases in dorsolateral frontal cortical areas of both hemispheres. The ABR results showed signs of dysfunction at least at the brain stem level and the oculomotor tests showed high frequency of pathology.

A rapid transport route between the epidural space and the intraneural capillaries of the nerve roots.

Study Design: The possibility of epidurally applied substances reaching the intraneural capillaries of the spinal nerve roots and cauda equina was assessed in the pig sacrococcygeal spine.

Methods: The presence of Evans blue-labelled albumin in intraneural capillaries after epidural application for 1, 10, or 30 minutes was studied with fluorescence microscopy. Ink angiography was used to determine whether there were any direct communicating vessels between the epidural vein plexus and the intraneural capillaries.

International experience with tiagabine add-on therapy.

Tiagabine (TGB) hydrochloride is a novel antiepileptic drug (AED) that is a potent and specific inhibitor of gamma-aminobutyric acid (GABA) uptake into glial and neuronal elements. In accordance with medical and regulatory standards, the clinical development program for TGB as an AED has assessed the value of TGB in add-on treatment, focusing mainly on partial seizures, including secondarily generalized seizures. Five add-on, placebo-controlled trials and six noncomparative, open-label, long-term multicenter trials have been or are being conducted in Australia, Europe, and the U.

Isthmic spondylolisthesis among patients receiving disability pension under the diagnosis of chronic low back pain syndromes.

Objectives: This study evaluated the incidence of lumbar isthmic spondylolisthesis among subjects permanently disabled because of low back pain syndromes.

Summary Of Background Data: Previous information pointed to whether spondylolisthesis is associated with more frequent or intensive low back pain than that found in the general population. One may expect severe deformity, neurologic deficits, and hence impairment and disability accompanying such a spinal disorder.

The discharge behaviour of single vasoconstrictor motoneurones in human muscle nerves.

1. The discharge behaviour of fourteen single sympathetic vasoconstrictor efferents was studied using a tungsten microelectrode inserted percutaneously into a motor fascicle of the radial or peroneal nerve in eight awake supine subjects. Units were classified as vasoconstrictor because their firing properties correlated appropriately to changes in cardiac interval and arterial pressure.

Prevention of iron deficiency.

This chapter discusses different methods to prevent iron deficiency--to reduce iron losses (e.g. reducing menstrual iron losses by using a contraceptive pill or combating of hookworm infestation) or to increase iron absorption.

Increased metal release from cemented femoral components made of titanium alloy. 19 hip prostheses followed with radiostereometry (RSA).

In 19 patients the concentrations of metal were measured in serum, urine and joint fluid 2 years after implantation of uncemented commercially pure titanium acetabular cups and cemented or uncemented femoral components made of titanium alloy. A ceramic against the polyethylene articulation was used. The fixation of the components was followed with radiostereometry (RSA).

Does early micromotion of femoral stem prostheses matter? 4-7-year stereoradiographic follow-up of 84 cemented prostheses.

Roentgen stereophotogrammetry was used to measure the migration of the centre of the femoral head in 84 cemented Lubinus SP I hip arthroplasties (58 primary operations, 26 revisions). Four to seven years later, seven femoral components had been revised because of painful loosening. These implants showed greater subsidence, medial migration and posterior migration during the first two postoperative years than did the hips which had not been revised.

The effect of seat back inclination on spine height changes.

The effect of backrest inclination on spinal height changes was tested during static sitting and seated whole-body vibrations. The vibration input was sinusoidal with a frequency of 5 Hz and an acceleration of 0.1 g rms.

A new method for the relative quantification of rCBF examined by 99Tcm-HMPAO SPECT.

A new method for the analysis of regional cerebral blood flow (rCBF) studies, the 'Min-Max' method, was compared with the conventional method, the 'Average' method. Regional CBF was examined by single photon emission computed tomography (SPECT) using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO). The two methods were used to quantify the rCBF in a population of patients with various dementia disorders, and in healthy controls.

Dilated cardiomyopathy and the dystrophin gene: an illustrated review.

Cardiomyopathy is often found in patients with Duchenne and Becker muscular dystrophy, which are X linked muscle diseases caused by mutations in the dystrophin gene. Dystrophin defects present in many different ways and cases of mild Becker muscular dystrophy have been described in which cardiomyopathy was severe. Female carriers of Duchenne muscular dystrophy can develop symptomatic skeletal myopathy alone or combined with dilated cardiomyopathy.

Long-term home self-treatment with high thoracic epidural anesthesia in patients with severe coronary artery disease.

Twenty patients with severe coronary artery disease (CAD) and refractory unstable angina who had sustained a recent myocardial infarction (n = 7) or who were considered as either inoperable (n = 10) or at severe operative risk (n = 3) were treated with high thoracic epidural anesthesia (TEA) via a tunneled epidural catheter for long-term self-use at home. They were instructed to use sublingual nitrates as their first treatment for angina and to inject 3-5 mL of bupivacaine (5 mg/mL) into the epidural catheter only for severe episodes. The epidural catheters were maintained for long periods (mean, 6 mo; longest treatment, 3.

Quantitative SPECT cisternography in normal pressure hydrocephalus.

Twenty-one patients with normal pressure hydrocephalus (NPH), 8 patients with various brain diseases with an element of hydrocephalus, and 7 patients with miscellaneous dementia disorders were investigated with quantitative radionuclide cisternography (RC) using single photon emission computerized tomography (SPECT). The total intracranial counts as well as the counts in the lateral and third ventricles were measured. All 15 NPH patients accessible for postoperative examination were improved after shunt surgery.

Effects of methylprednisolone on nucleus pulposus-induced nerve root injury.

Study Design: The effects of intervention by intravenous injection of methylprednisolone to reduce the nerve root injury after epidural application of autologous nucleus pulposus was studied in an experimental model on the pig cauda equina in 20 animals.

Methods: Nucleus pulposus was harvested from a lumbar disc. After lowering the pH of the nucleus pulposus to 3.

Long-term results of Charnley arthroplasty. A 12-16-year follow-up study.

A retrospective, long-term study was initiated to analyze clinical function, failures, and radiographic status in 95 Charnley low-friction arthroplasties performed during 1973-1977. Only patients with primary osteoarthrosis were included, and no patients were lost during the follow-up period. At the follow-up evaluation, 39 patients (41 hips) were deceased.