Lumbar Root Stimulation for Restoring Leg Function: Results in Paraplegia

Abstract: We have implanted an intradural array of 12 tripolar electrodes on the anterior roots L2-S2, left and right, at cauda equina level, in a 33-year-old woman with a complete T9 cord lesion of 3 years' duration. They are driven by an implanted multiplexed stimulator system using radio frequency (RF) power and control signals. All channels generate movements, in patterns that might be predicted from the known anatomy of the cauda equina. In particular, stimulation of L2 and L3 gives hip adduction; L3, L4, and L5 gives quadriceps femoris movements; L5, S1, and S2 gives hamstrings movement; and S1 and S2 give plantar flexion. Stimulation of L5 gives mixed movements at the ankle. Surprisingly, stimulation of the L2 roots has not given strong hip flexion. Responses have been stable. Some thresholds have varied, probably as a result of tissue encapsulation. The moment generated within each degree of freedom of the legs has been measured for each root, using a specially designed multimoment measurement apparatus. For several roots, a movement of lower threshold may be accompanied by a second movement of higher electrical threshold, suggesting that different muscles may have fiber populations that differ in their diameter or their location in the root. The use of stimulus forms that enable selective anodal block may, in the future, enable separation of two distinct movements from a single motor root.     

Improving Risk Assessment: Hip Geometry, Bone Mineral Distribution and Bone Strength in Hip Fracture Cases and Controls. The EPOS Study

Hip geometry and bone mineral density (BMD) have previously been shown to relate independently to hip fracture risk. Our objective was to determine by how much hip geometric data improved the identification of hip fracture. Lunar pencil beam scans of the proximal femur were obtained. Geometric and densitometric values from 800 female controls aged 60 years or more (from population samples which were participants in the European Prospective Osteoporosis Study, EPOS) were compared with data from 68 female hip fracture patients aged over 60 years who were scanned within 4 weeks of a contralateral hip fracture. We used Lunar DPX ‘beta’ versions of hip strength analysis (HSA) and hip axis length (HAL) applied to DPX(L) data. Compressive stress (Cstress), calculated by the HSA software to occur as a result of a typical fall on the greater trochanter, HAL, body mass index (BMI: weight/(height)²) and age were considered alongside femoral neck BMD (FN-BMD, g/cm²) as potential predictors of fracture. Logistic regression was used to generate predictors of fracture initially from FN-BMD. Next age, Cstress (as the most discriminating HSA-derived parameter), HAL and BMI were added to the model as potentially independent predictors. It was not necessary to include both HAL and Cstress in the logistic models, so the entire data set was examined without excluding the subjects missing HAL measurements. Cstress combined with age and BMI provided significantly better prediction of fracture than FN-BMD used alone as is current practice, judged by comparing areas under receiver operating characteristic (ROC) curves (p<0.001, deLong’s test). At a specificity of 80%, sensitivity in identification was improved from 66% to 81%. Identifying women at high risk of hip fracture is thus likely to be substantially enhanced by combining bone density with age, simple anthropometry and data on the structural geometry of the hip. HSA might prove to be a valuable enhancement of DXA densitometry in clinical practice and its use could justify a more pro-active approach to identifying women at high risk of hip fracture in the community. Received: 16 March 2001 / Accepted: 3 August 2001     

Bladder distention and pyelectasis in the male fetus: causes,comparisons, and contrasts.

The objective of this paper was to determine if prenatal sonographic findings can accurately differentiate between the causes of bladder distention and pyelectasis in the male fetus. Twenty-one cases were evaluated for the presence of oligohydramnios, posterior urethral dilation, bladder wall thickening, urachal patency, cortical thinning, cortical cysts, and increased renal echogenicity. Postnatal diagnosis included posterior urethral valves (10 cases), prune belly syndrome (four cases), vesicoureteral reflux (four cases), left ureterovesical junction obstruction (one case), and nonrefluxing, nonobstructive megacystis-megaureter (two cases). Oligohydramnios was present in eight of 10 cases of posterior urethral valves and in one of four cases of prune belly syndrome. A dilated posterior urethra was noted in seven of 10 cases of posterior urethral valves and transiently in two of four cases of prune belly syndrome. Bladder wall thickening developed in all cases of posterior urethral valves and was noted in two of four patients with prune belly syndrome. A patent urachus likewise was identified in two of four cases of prune belly syndrome. The presence of oligohydramnios, progressive bladder wall thickening, and dilated posterior urethra was most suggestive of posterior urethral valves, whereas the presence of a patent urachus was most suggestive of prune belly syndrome. The presence of pyelectasis and megacystis without additional amniotic fluid, bladder, urethral, or renal abnormalities was most suggestive of vesicoureteral reflux, ureterovesical junction obstruction, or nonrefluxing, nonobstructive megacystis-megaureter. Owing to the overlap and evolution of these findings, close follow-up evaluation is recommended.     

Prevention and treatment of experimental influenza A virus infection in volunteers with a new antiviral ICI 130,685

The initial prophylactic and therapeutic trials of ICI 130,685 against influenza A virus infection are reported. Prophylaxis with either 200 mg/day (38 volunteers received drug and 40 received placebo) or 100 mg/day (28 volunteers received drug and 28 received placebo) for seven days significantly reduced illness, mean clinical score and nasal secretion weight when volunteers were challenged with 10(4.1) EID50 of influenza virus A/Eng/40/83 (H3N2). Overall, prophylaxis with 200 mg/day and 100 mg/day gave 91% and 72% protection against illness relative to placebo, respectively. In addition, prophylaxis with both regimens for seven days also significantly reduced the number of volunteers who excreted virus. In a therapeutic study, volunteers were inoculated with the same dose of virus and those who developed symptoms which persisted for 6-15 h were treated with 200 mg/day of drug (20 volunteers) or placebo (19 volunteers) for four days. Generally, treatment reduced both the amount of virus excreted and the mean daily clinical score. However, these reductions were only statistically significant (P less than 0.05) on the third day of medication for the amount of virus excreted and on the fourth day of treatment for the mean clinical score. It was concluded that ICI 130,685 is effective in the prevention and treatment of influenza virus infection. An initial tolerance study in 16 volunteers who received either drug (200 mg/day) (8 volunteers) or placebo (8 volunteers) for seven days, indicated that the drug was generally well tolerated. Combining data from all studies, 43% of volunteers who received the drug at the 200 mg/day dosage and 21% who received placebo complained of one or more symptoms. However, symptoms were generally minor and of short duration. At the lower dosage (100 mg/day) the symptoms were qualitatively similar to those reported with placebo.     

The epidemiology of atypical mycobacterial diseases in northern England: a space-time clustering and Generalized Linear Modelling approach

The incidence of infection by mycobacteria, other than tubercle bacilli (MOTT) is increasing in the United Kingdom, Europe and the United States. These diseases increase morbidity and are an increasing public health concern. However, the epidemiology of disease due to these species is not well characterized. We used space-time clustering approaches and Generalized Linear Modelling to investigate the potential predictors of disease in cases of infection by organisms of the Mycobacterium avium complex (MAC) and M. malmoense recorded in the north of England during 2000-2005. There was significant spatial and temporal clustering in juvenile cases of infection by MAC but not for cases of infection in adults by either species. There were no significant predictors of infection by M. malmoense or juvenile cases of M. avium. Incidence of disease caused by M. avium in adults was significantly related to health deprivation and weakly related to rainfall. We consider possible reasons for the difference in epidemiology in infection by M. avium in adults and juveniles.     

Comparison of written and oral examinations in a baccalaureate medical-surgical nursing course.

Nursing students traditionally have been evaluated with an objective written examination. This method has shown some benefits and disadvantages. This project examined the value of oral examinations in evaluating nursing students. Five groups of students were evaluated with different forms of testing, some with only written tests, others with only oral examinations, some with a combination of both types of evaluations. The results showed that oral examinations can effectively evaluate the student's comprehension and application of clinical information in a clinical situation, as shown in higher test results, compared with oral written examinations, and positive student comments. Oral examination can be as effective or more effective in evaluating student understanding of medical/surgical content and its application in clinical situations.     

Heterogeneity of human red cell autoantibodies assessed by isoelectric focusing

Human red cell (RBC) autoantibodies may be the products of a single lymphocyte clone or of a restricted number of clones. For insight into the clonal distribution of human RBC autoantibodies, serum fractions from 28 individuals with various forms of autoimmune hemolytic anemia (AHA) and two nonanemic individuals with positive direct antiglobulin tests were separated by isoelectric focusing (IEF), and RBC binding in each fraction was quantitated with a solid-phase radioimmunoassay. IEF fractions of serum from normal volunteers and patients with nonimmune hemolytic anemia served as controls. These studies indicate that RBC antibodies are found in a restricted number of IEF fractions in sera from some patients with immune hemolytic anemia. IEF fractions containing RBC-binding activity vary among patients with idiopathic AHA, and distinct patterns of binding activity are found in serum from some patients with AHA associated with alphamethyldopa and procainamide or with B-cell immunoproliferative diseases. These findings suggest that the mechanism leading to autoantibody production may differ among patients with the various forms of immune hemolytic anemia.