Radiological outcome of short segment posterior stabilisation and fusion in thoracolumbar spine acute fracture.

INTRODUCTION: The optimal management of thoracolumbar spine fractures remains a matter of controversy. The current literature implies that the use of short-segment pedicle screw fixation may be inappropriate because of its high reported failure rate. The purpose of this study is to report the short-term results of thoracolumbar burst and compression fractures treated with short-segment pedicle instrumentation. MATERIALS AND METHODS: From 2002 to 2007, 19 patients with thoracolumbar acute traumatic fractures were instrumented with posterior short-segment pedicle screws. The patients' case notes, operation records, preoperative and postoperative radiographs (sagittal index, anterior body compression and regional kyphosis), computed tomography scans, neurological findings (Frankel functional classification), and follow-up records up to 18 months were reviewed. RESULTS: A statistically significant difference was found between the patients' preoperative, postoperative and follow-up sagittal index, anterior body compression and regional kyphosis measurement. One case resulted in screw pedicle screw pullout and subsequently, kyphotic deformity. The patient underwent revision surgery to long-segment posterior instrumentation and fusion. None of the patients showed an increase in neurological deficit. CONCLUSION: In conclusion, the short-term follow-up results suggest a favourable outcome for short-segment instrumentation. Load shearing classification is essential for the selection of patient for short-segment instrumentation. However, the long-term follow-up evaluation will be needed to verify our findings.

Radiological outcome of short segment posterior stabilisation and fusion in thoracolumbar spine acute fracture

<p><b>INTRODUCTION</b>The optimal management of thoracolumbar spine fractures remains a matter of controversy. The current literature implies that the use of short-segment pedicle screw fixation may be inappropriate because of its high reported failure rate. The purpose of this study is to report the short-term results of thoracolumbar burst and compression fractures treated with short-segment pedicle instrumentation.</p><p><b>MATERIALS AND METHODS</b>From 2002 to 2007, 19 patients with thoracolumbar acute traumatic fractures were instrumented with posterior short-segment pedicle screws. The patients' case notes, operation records, preoperative and postoperative radiographs (sagittal index, anterior body compression and regional kyphosis), computed tomography scans, neurological findings (Frankel functional classification), and follow-up records up to 18 months were reviewed.</p><p><b>RESULTS</b>A statistically significant difference was found between the patients' preoperative, postoperative and follow-up sagittal index, anterior body compression and regional kyphosis measurement. One case resulted in screw pedicle screw pullout and subsequently, kyphotic deformity. The patient underwent revision surgery to long-segment posterior instrumentation and fusion. None of the patients showed an increase in neurological deficit.</p><p><b>CONCLUSION</b>In conclusion, the short-term follow-up results suggest a favourable outcome for short-segment instrumentation. Load shearing classification is essential for the selection of patient for short-segment instrumentation. However, the long-term follow-up evaluation will be needed to verify our findings.</p>

Distributed neural system for general intelligence revealed by lesion mapping.

General intelligence (g) captures the performance variance shared across cognitive tasks and correlates with real-world success. Yet it remains debated whether g reflects the combined performance of brain systems involved in these tasks or draws on specialized systems mediating their interactions. Here we investigated the neural substrates of g in 241 patients with focal brain damage using voxel-based lesion-symptom mapping. A hierarchical factor analysis across multiple cognitive tasks was used to derive a robust measure of g. Statistically significant associations were found between g and damage to a remarkably circumscribed albeit distributed network in frontal and parietal cortex, critically including white matter association tracts and frontopolar cortex. We suggest that general intelligence draws on connections between regions that integrate verbal, visuospatial, working memory, and executive processes.

Drug resistance in Mycobacterium tuberculosis isolates from tuberculosis patients in Kerala, India.

OBJECTIVE: To analyse the extent of drug resistance in clinical isolates of Mycobacterium tuberculosis from patients attending various tuberculosis (TB) clinics in Kerala, India. DESIGN: Mycobacteria were isolated from sputum samples of TB patients. Isolates from 92 new and 104 retreatment cases were tested for resistance to four first-line drugs (isoniazid, rifampicin, ethambutol and streptomycin). RESULTS: Twenty-three per cent of the isolates from new cases and 14% from retreatment cases were pan-susceptible, and the rest were resistant to at least one of the drugs. Multidrug-resistant isolates accounted for 5.4% among new cases and 16.4% among retreatment cases. It should be noted that 18.5% of the isolates were mycobacteria other than tuberculosis. CONCLUSION: There is an urgent need for statewide surveys to assess the level of drug resistance using quality-assured culture and drug susceptibility services. Considering that the Revised National TB Control Programme in India has been made operational nationwide, this kind of screening should be made mandatory under the programme to effectively control the spread of TB.

Symptomatic spinal epidural varices presenting with nerve impingement: report of two cases and review of the literature.

STUDY DESIGN: Two cases of symptomatic epidural varices are presented and the literature was reviewed on this entity. OBJECTIVE: To raise awareness of this rare condition in the interpretation of preoperative magnetic resonance imaging scans and to assess the results of surgical treatment. BACKGROUND: Symptomatic epidural varices presenting with radiculopathy are extremely rare, and the diagnosis is often missed in the preoperative evaluation. This condition commonly masquerades as a herniated nucleus pulposus. Diagnosis is often only made intraoperatively. MATERIALS AND METHODS: Case 1 is a 40-year-old man presenting with acute exacerbation of lower back pain associated with radiculopathy down his right lower limb. Magnetic resonance imaging showed a paracentral disc prolapse. At operation, a congested epidural vein impinging on the L5 nerve root was noted with no intervertebral foramens stenosis. Excision of the vein was performed. The second case, a 50-year-old man with previous spinal instrumentation, was admitted for acute onset of radiculopathy down his left lower limb. At operation, an epidural varix compressing on the L4 nerve root was noted. Retrospectively, features of epidural varices were noted in the preoperative magnetic resonance imaging scans. Both patients reported resolution of symptoms after surgery. RESULTS: Excision was done for the first patient, and coagulative ablation was done in the second patient. Both patients had symptomatic relief and neurologic recovery on follow-up. CONCLUSION: Our experience and the literature demonstrated that a favorable outcome with resolution of neurologic symptoms can often be achieved after excision or ablation of the epidural varices.

Interhemispheric Stroop effects in partial and complete agenesis of the corpus callosum.

Previous research had demonstrated diminished interhemispheric Stroop effects in individuals with agenesis of the corpus callosum (ACC), suggesting an important role for the callosum in interhemispheric color-word and color-patch interactions. However, this outcome rested on the results of only 1 ACC participant, who had normal intelligence and a minimum of other neuropathology. In the research reported herein, the role of the corpus callosum in interhemispheric Stroop interference and facilitation was investigated in 9 individuals with complete or partial ACC and normal intelligence, and in non-ACC controls. Congruent, incongruent, or neutral stimulus pairs were presented either unilaterally (color-patch and color-word in the same visual field) or bilaterally (color-patch and color-word in different visual fields). Both unilateral and bilateral (interhemispheric) Stroop interference were found for both ACC and non-ACC groups, with no significant difference in magnitude, indicating that extracallosal pathways are sufficient for mediating this phenomenon. It is suggested that the anterior commissure is a more likely candidate for the interhemispheric transmission of the semantic information resulting in Stroop interference.

Studies of the subtilin leader peptide as a translocation signal in Escherichia coli K12.

Subtilin is an antimicrobial peptide of the lantibiotic family that is produced by Gram-positive Bacillus subtilis, and its biosynthesis involves expression of presubtilin which consists of a leader segment and a mature segment. The leader segment is unlike a typical sec-type general secretion signal, and its ability to mediate translocation through a non-sec pathway has been previously studied by fusing the subtilin leader to an alkaline phosphatase reporter and expressing it in B. subtilis 168 [Izaguirre, G. and Hansen, J. N. (1997) Appl. Environ. Microbiol. 63, 3965-3971]. In this work, we have expressed the same subtilin leader-AP fusion in Gram-negative Escherichia coli, and found that the AP polypeptide is translocated into the periplasmic compartment and assembles into an enzymatically active form. The subtilin leader segment was not cleaved from this enzymatically active AP, which remained associated with the membrane. Conversion of the cells to spheroplasts followed by treatment with proteinase K showed that about 50% of the bound AP was sufficiently exposed on the surface of the spheroplasts to be inactivated by proteolytic cleavage.

Colonization with vancomycin-resistant Enterococcus faecium: comparison of a long-term-care unit with an acute-care hospital.

OBJECTIVE: To compare the epidemiology of vancomycin-resistant Enterococcus faecium (VRE) in a long-term-care unit and an acute-care hospital. DESIGN: Point-prevalence surveys for VRE rectal colonization of patients were carried out over a 21-month period in patients in a long-term-care unit and an acute-care hospital (medical ward and intensive-care units). The environment and hands of healthcare workers also were sampled for VRE. Contour-clamped homogeneous electric field (CHEF) electrophoresis was used to evaluate possible transmission among roommates and the relatedness of patient strains to those in the environment and on the hands of healthcare workers. SETTING: A 200-bed Veterans Affairs Medical Center with an attached 90-bed long-term-care unit. RESULTS: From December 1994 to January 1996, rectal VRE colonization of patients in the long-term-care unit increased significantly from 9% to 22%. In contrast, patients on the medical ward rarely were colonized after the first survey in December 1994, and only two intensive-care-unit patients were found to be colonized during the four surveys. The environment was contaminated persistently in the long-term-care unit. In the four surveys, carriage of VRE on hands of healthcare workers varied from 13% to 41%; 65% of healthcare workers with VRE found on their hands worked in the long-term-care unit. Seven different strains were identified by CHEF typing. Although the initial survey found only vanA strains, subsequent surveys showed vanB strains also were present. CONCLUSIONS: Residents of a long-term-care unit frequently were colonized with VRE, but infections were uncommon in this population. The environment of the long-term-care unit was contaminated with VRE, and VRE was found frequently on the hands of healthcare workers in this unit. Both vanA and vanB genotypes were found in this setting.