[Neurogenic muscle hypertrophy: imaging features in three cases and review of the literature]. / Hypertrophie musculaire neurogène: à propos de trois cas, imagerie et revue de la littérature.

OBJECTIVE: To review the literature on well-documented cases of neurogenic muscle hypertrophy in order to define significant features of this disease. PATIENTS AND METHODS: The PUBMED and SCIENCE DIRECT web-sites were used to conduct an inventory of all reported cases of this disease. We entered the key-words "hypertrophy", "muscle" and "neurogenic", and found 48 articles, describing 129 cases. Our criteria of inclusion included hypertrophy of one or several muscles of a lower limb, previous realization of at least one imaging study (CT or MRI) and electromyography of lower limbs; criterion of exclusion was hypertrophy related to hereditary or acquired polyneuropathies. Twenty-five cases were retained for investigation along with 3 recent cases observed in our department. RESULTS: Results show that neurogenic muscle hypertrophy is usually presents with painful enlargement of a calf in a male, aged 32 to 60 years, with previous history of low back pain and sciatica, 68% of the time due to disk herniation or lumbar stenosis. Other clinical findings may include radiation therapy or trauma. CONCLUSION: The symptoms of neurogenic muscle hypertrophy may lead to MRI examination before electromyography. This disease should be included in the differential diagnosis.

System analysis of patient management during the pre- and early clinical phase in severe head injury.

Head injury with or without polytrauma is the most important cause of death and severe morbidity in an age bracket of up to 45 years. Two major factors are determining its outcome, the extent and nature of the primary irreversible brain injury, and the subsequently developing manifestations of secondary brain damage, which in principle can be prevented by the management procedures and therapeutical interventions. Therefore, a better outcome from severe head injury depends exclusively on a higher efficiency of the management and treatment in order to inhibit secondary brain damage. In a novel nationwide research program on "Neurotraumatology and Neuropsychological Rehabilitation" sponsored by the Federal Government, the University of Munich in collaboration with the Max-Planck-Institute of Neurobiology, Martinsried, formed a research consortium with major city hospitals in Munich, Augsburg, Ingolstadt, Murnau, Vogtareuth, and the Southern Bavaria rural area, which are caring for neurotrauma patients with severe head- or spinal cord injury. Together with the corresponding rescue- and emergency organizations, such as the Red Cross, fire brigades, etc. the consortium is carrying out a system analysis as a joint venture on the organization, logistics, management, patient referral, etc. in severe head injury. The analysis includes the assessment of outcome-relevant time intervals of providing emergency care during the preclinical phase until admission of the patient to the hospital, until termination of the diagnostic procedures after hospital admission, and of the clinical management. The present findings and results are based on these comprehensive investigations by the study group in collaboration with more than 30 hospitals, institutions, organizations, and of more than forty physicians, students, and statisticians. In total 194 patients suspected to suffer from severe head injury were prospectively documented with onset of the assessment in the preclinical rescue phase. Confirmation of severe head injury according to a priori established selection criteria was obtained in 100 patients, the remaining number of cases was excluded. The protocol by purpose did not impose study-specific requirements outside of the routine procedures, which are established for the preclinical care and early hospital management. An exception, however, was to collect arterial blood samples, if possible prior to intubation and ventilation, or administration of O2, in order to obtain early information on the acute respiratory state as a potential risk factor of the outcome. Arterial blood samples could be collected in 60 cases at the scene, in no less than 37 patients prior to intubation and ventilation. The data collected during the prehospital and early clinical phase on the temporal course of these patients provide valuable information with unmatched accuracy for evaluation of the management efficiency of the rescue system, transportation, and the clinical care. In conclusion, the prospective system analysis on the organization and management of patients with severe head injury is the first study of this type carried out in Germany. Due to the specific efforts of quasi on-line documentation of the patients' state and course of events, beginning at the scene of an accident and covering the first days at the hospital, data of high quality were obtained. The data flow during the investigation was maintained among others by regular conferences of the Study Group including the crew of documentation assistants at regular intervals. The presently reported phase-1 study was concluded in October 1997. It is followed by a phase-2 study with the attempt to collect prehospital- and early clinical management and care data in the catchment area on an epidemiological basis. (ABSTRACT TRUNCATED)

Prospective documentation and analysis of the pre- and early clinical management in severe head injury in southern Bavaria at a population based level.

Treatment of patients suffering from severe head injury is so far restricted to general procedures, whereas specific pharmacological agents of neuroprotection including hypothermia have not been found to improve the outcome in clinical trials. Albeit effective, symptomatic measures of the preclinical rescue of patients (i.e. stabilization or reestablishment of the circulatory and respiratory system) or of the early clinical care (e.g. prompt diagnosis and treatment of an intracranial space occupying mass, maintenance of a competent circulatory and respiratory system, and others) by and large constitute the current treatment based on considerable organizational and logistical efforts. These and other components of the head injury treatment are certainly worthwhile of a systematic analysis as to their efficacy or remaining deficiencies, respectively. Deficits could be associated with delays of providing preclinical rescue procedures (e.g. until intubation of the patient or administration of fluid). Delays could also be associated in the hospital with the diagnostic establishment of intracranial lesions requiring prompt neurosurgical intervention. By support of the Federal Ministry of Education and Research and under the auspices of the Forschungsverbund Neurotraumatology, University of Munich, a prospective system analysis was carried out on major aspects of the pre- and early clinical management at a population based level in patients with traumatic brain injury. Documentation of pertinent data was made from August 1998 to July 1999 covering a catchment area of Southern Bavaria (5.6 mio inhabitants). Altogether 528 cases identified to suffer from severe head injury (GCS < or = 8 or deteriorating to that level within 48 hrs) were enrolled following admission to the hospital and establishment of the diagnosis. Further, patients dying on the scene or during transport to the hospital were also documented, particularly as to the frequency of severe head injury as underlying cause of mortality. The analysis included also cases with additional peripheral trauma (polytrauma). The efficacy of the logistics and organization of the management was studied by documentation of prognosis-relevant time intervals, as for example until arrival of the rescue squad at the scene of an accident, until intubation and administration of fluid, or upon hospital admission until establishment of the CT-diagnosis and commencement of surgery or transfer to the intensive care unit, respectively. The severity of cases studied in the present analysis is evident from a mortality of far above 40% of cases admitted to the hospital, which was increased by about 20% when including prehospital mortality. The outcome data notwithstanding, the emerging results demonstrate a high efficacy of the pre- and early clinical management, as indicated by a prompt arrival of the rescue squad at the scene, a competent prehospital and early clinical management and care, indicative of a low rate of avoidable complications. It is tentatively concluded on the basis of these findings that the patient prognosis is increasingly determined by the manifestations of primary brain damage vs. the development of secondary complications.

Neuroscience robotics to investigate multisensory integration and bodily awareness.

Humans experience the self as localized within their body. This aspect of bodily self-consciousness can be experimentally manipulated by exposing individuals to conflicting multisensory input, or can be abnormal following focal brain injury. Recent technological developments helped to unravel some of the mechanisms underlying multisensory integration and self-location, but the neural underpinnings are still under investigation, and the manual application of stimuli resulted in large variability difficult to control. This paper presents the development and evaluation of an MR-compatible stroking device capable of presenting moving tactile stimuli to both legs and the back of participants lying on a scanner bed while acquiring functional neuroimaging data. The platform consists of four independent stroking devices with a travel of 16-20 cm and a maximum stroking velocity of 15 cm/s, actuated over non-magnetic ultrasonic motors. Complemented with virtual reality, this setup provides a unique research platform allowing to investigate multisensory integration and its effects on self-location under well-controlled experimental conditions. The MR-compatibility of the system was evaluated in both a 3 and a 7 Tesla scanner and showed negligible interference with brain imaging. In a preliminary study using a prototype device with only one tactile stimulator, fMRI data acquired on 12 healthy participants showed visuo-tactile synchrony-related and body-specific modulations of the brain activity in bilateral temporoparietal cortex.

A Haptic Interface Based on Potential Mechanical Energy to Investigate Human Motor Control using fMRI.

This paper describes a mechanical interface to use in conjunction with fMRI, in order to infer the brain mechanisms of human motor learning. Innovative mechanical concepts based on gravity and elastic forces were used to generate typical stable and unstable dynamic interactions at the hand during multijoint arm movements. Two designs were retained and implemented from MR compatible materials. The first uses a spring constrained between two specially designed surfaces and the other a capstan to transform the force induced by a groove carved on a shaft. These two degree-of-freedom mechanical interfaces have been constructed and tested. The use of a capstan mechanism was found to be limited by excessive friction, however, the method using a machined surface provides a simple and effective interface to investigate human motor control.

Special aspects of severe head injury: recent developments.

Trauma in general, and head injury in particular, is the most frequent cause of mortality and morbidity in those aged up to 45 years. Outcome from severe head injury depends on the nature and severity of the primary lesion, and the manifestations of secondary brain damage of extra- and intracranial origin. The most important sequela is cerebral ischaemia resulting from intracranial hypertension caused by, for example, traumatic brain swelling or intracranial haemorrhage and/or systemic complications, of which arterial hypotension is the most significant. Because treatment so far is limited in principle to general symptomatic measures, continuing improvements in patient management is required on a comprehensive basis. In this context, major efforts are being made all over the world, not only to assess the current efficacy of, for example, logistics, organization and patient management in severe head injury, but also towards development of a consensus aimed at standardizing management and treatment procedures. With regard to the predominant influence of secondary ischaemia of the brain, recent experimental and clinical pathophysiological studies focus on the quality of cerebral blood flow, including the intriguing phenomenon of post-traumatic vasospasm. Other research objectives are concerned with the role of cytokines, leucocyte-endothelial interactions and molecular genetics in severe head injury (e.g. illuminated by the emerging role of the apolipoprotein E gene). Finally, the formation of international organizations, the American and European Brain Injury Consortium, is noteworthy. Although their primary objective is the development of guidelines for clinical trials, future objectives are conceivably more far spread and influential. It can be hoped, therefore, that the unacceptably poor outcome from severe head injury until now can be improved. Moreover, alleged management discrepancies between up-to-date trauma centres and rural hospitals may be eliminated.

MR imaging evaluation of suprascapular nerve entrapment.

The aim of this study was to assess the significance of muscular edema, atrophy, and fatty changes in the diagnosis of suprascapular nerve entrapment (SSNE), and to confirm muscular edema as the most significant sign of neuropathy. A retrospective study of 18 patients with suprascapular nerve entrapment was performed. All patients underwent electromyographic studies and MR imaging with a 1.5-T Echo Speed system (General Electric, Milwaukee, Wis.). The diagnosis of muscle edema was reached when muscles presented a high signal on T2-weighted fast spin-echo (SE) fat-suppressed images. Muscular trophicity and fatty changes were analyzed on a sagittal oblique cut using SE T1-weighted images. Intra- and inter-observer reproducibility using kappa test, sensitivity, and specificity were analyzed, together with negative and positive predictive value of each criterion. The topographic diagnosis was correct as edema affected the infraspinatus muscle alone when the suprascapular nerve was entrapped at the spinoglenoid notch. Both the supraspinatus and infraspinatus muscles were affected when nerve was compressed at the suprascapular notch. Sensitivity and specificity of muscular edema were, respectively, 94.5 and 100%. Muscular atrophy sensitivity and specificity were 81 and 80%, respectively. Fatty changes sensitivity and specificity were 25 and 96%, respectively. Muscular edema seems to be a more sensitive sign of SSNE than muscle atrophy and fatty changes when compared with EMG results. Magnetic resonance imaging can reach a positive, topographic, and etiologic diagnosis of SSNE.