Different microbial biofilm formation on polymethylmethacrylate (PMMA) bone cement loaded with gentamicin and vancomycin.

We studied the in vitro effects of gentamicin and vancomycin alone and in combination added to polymethylmethacrylate (PMMA) cement specimens on the bacterial adhesion of multiresistant clinical isolates. The PMMA specimens (discs) loaded with gentamicin (1.9%) or vancomycin (1.9%) or with a combination of the two were placed in Mueller-Hinton Broth inoculated with bacterial strains. After incubation, bacterial growth was determined by optical density (OD(540)) and sub-cultures. The biofilm PMMA-associated dye (crystal violet) was measured. Antibiotic concentrations in broth were determined by fluorescence polarisation immunoassay. All antibiotic-loaded PMMA cement specimens released high, inhibitory concentrations of gentamicin and vancomycin. However, differences in strain growth and adhesion were recorded. The clinical isolates Met-R/Gent-R CoNS showed no adhesion to gentamicin-loaded specimens for 24 h; strains with Gent-Intermediate susceptibility exhibited growth after 48 h but reduced adhesion. Some Gent-R strains exhibited growth and adhesion to antibiotic-loaded specimens similar to controls (plain discs). Only the VRSA strain (Staphylococcus aureus 5/7) and Escherichia coli were able to grow and adhere to vancomycin-loaded specimens after 24 h of incubation. The specimens loaded with the gentamicin + vancomycin combination showed a synergistic inhibitory effect against all tested strains (no bacterial growth). The degree of bacterial adhesion to PMMA cement loaded with gentamicin or vancomycin may be reduced in spite of a normal growth rate and is different for the tested strains. The effect of gentamicin and vancomycin on bacterial growth and adhesion to PMMA bone cement depends on the antibiotic concentrations, on the characteristics of each specific strain and on its ability to produce biofilm and adhere to antibiotic-loaded PMMA bone cement.

Community level risk factors for numbers of landmine victims in Chad and Thailand.

STUDY OBJECTIVE: To determine commonalities of landmine victim risk factors in two very different countries. DESIGN AND SETTING: Data on 249 communities in Chad and 530 in Thailand were collected during 2000-2001 as part of the Global Landmine Survey. Community level variables were analysed in a series of Poisson mixture models with number of landmine victims as the dependent variable. Models developed for each country were tested on the other to investigate similarities and robustness of identification of risk factors. MAIN RESULTS: Increased community level risk was associated with population size, closeness to another community with victims, emplacement in the previous two years, blocked water or pasture, and the proximity of unexploded ordnance or anti-tank mines. In Chad, risk factors tended to be more related to identifying communities that had crossed a threshold between near zero and moderate risk; Thailand, factors were more related to increases in victim rates. CONCLUSIONS: Current systems of collecting data on community characteristics and landmine victims can provide meaningful risk factor information. Remediation approaches that focus on blockage of important resources and areas of recent, high intensity conflicts may be the most beneficial in reducing the numbers of victims.

Thoracic myelopathy due to enlarged ossified yellow ligaments. Case report and review of the literature.

Enlarged ossified yellow ligaments are a rare and poorly understood cause of thoracic myelopathy. The authors report the case of a patient in whom thoracic myelopathy was caused by enlarged ossified yellow ligaments.

Andreas Vesalius 1514-1564.

Andreas Vesalius was born in Brussels on December 31, 1514. After having spent some disappointing years at the Universities of Louvain and Paris, he graduated as Doctor of Medicine in Padua on December 5, 1537. The next day he was appointed as a teacher of both human anatomy and surgery. During the 6 years he held this chair, Vesalius engaged in impressive academic activities and published three masterly anatomic books: Tabulae Anatomicae Sex, De Humani Corporis Fabrica Libri Septem, and Epitome. The last two works contain anatomic woodcuts of incomparable artistic quality by Titian's pupils (by Stefan v. Calcar in particular). In 1544, at the age of 28, Vesalius gave up his chair and took up service as a court physician, first with Emperor Charles V and later with his son, Philip II of Spain. He died in 1564 on the small Greek island of Zante on return from a pilgrimage to the Holy Land. The gist of Vesalius' teaching was his conviction that valid anatomic knowledge could be gained only through dissection of the human corpse and not through the study of the traditional texts. Vesalius rid the study of human anatomy of mythic speculations, which had encrusted it for two millennia. Through Vesalius' work, human anatomy became an empirical science. Like Copernicus, Kepler, Bruno, and Galileo, Vesalius was one of the initiators of the new science. The tables of osteology and of the spine in Fabrica and Epitome are most impressive. Much of the nomenclature used for the spine today can be credited to him.

Release of antibiotics from polymethylmethacrylate cement.

The increase in resistance rates to antibiotics of bacteria isolated from infected hip joints, particularly staphylococci, prompted us to investigate the usefulness of antibiotic combinations such as gentamicin plus vancomycin. Cylinder test specimens of polymethylmethacrylate (PMMA) cement (Cemex, Tecres) containing gentamicin alone, vancomycin alone and both drugs in combination, were studied. The antibiotic concentrations were determined using a microbiological method and fluorescence polarization immunoassay (FPIA). The release of gentamicin alone, vancomycin alone and in combination from PMMA cement was prompt. The combination revealed synergistic antimicrobial activity against Escherichia coli and Enterococcus faecalis. FPIA showed that gentamicin and vancomycin delivery rates from PMMA cement were different. Gentamicin alone and in combination with vancomycin presented similar release rates from PMMA cement (1.50%). Vancomycin release from PMMA cylinders impregnated with the combination was lower (0.51%) than that from cylinders with vancomycin alone (1.16%). Vancomycin showed a 34.1% loss of microbiological activity at 37 degrees C after 10 days of incubation; the reduction corresponded to 15.0% when measured by FPIA. Results obtained with test specimens are indicative for the preparation of antibiotic-impregnated cements for different human prostheses.

Surgical treatment of cervical myelopathy of unclear aetiology.

In some cases neither the clinical pattern nor the findings of magnetic resonance imaging (MRI) can help to determine the cause of a cervical myelopathy. The differential diagnosis of such cases as a rule includes spondylotic myelopathy, a solitary focus of multiple sclerosis and an intramedullary tumour in early stage. Worsening of signs and symptoms due to the circumscribed lesion of the spinal cord can require surgical treatment, even if no certain diagnosis could be stated thus far. The question is how to choose a surgical procedure which is beneficial for all three kinds of spinal cord pathology in their initial stage, which at the same time does not jeopardise spine and spinal cord and allows secondary surgery if needed after the precise nature of the lesion has been assessed. Ventral decompression and fusion with or without dorsal decompression seems to be a convincing procedure.

Teratoma of the conus medullaris.

Intramedullary teratoma is a rare neoplasm. To our knowledge only 10 cases have been reported so far, eight of mature teratoma and two of immature. We present a new case of mature teratoma located in the conus medullaris. After 2 years increasing complaints and worsening neurologic deficits, the neoplasm was discovered by magnetic resonance imaging and was completely resected surgically. Similar cases are reviewed and the clinical, radiological, surgical and morphological aspects of this lesion will be discussed. In the majority of cases, the tumour has an indolent growth rate and recovery after resection is good.

Hemiballismus due to contralateral sphenoid ridge meningioma.

Primary intracranial tumour is a very uncommon cause of hemiballismus. In our review of the literature only two verified cases were found: one meningioma and one meningoblastoma. We report a patient with right hemiballismus due to a contralateral meningioma of the sphenoid ridge. His symptoms disappeared completely after resection of the tumour. The patient had no signs of increased intracranial pressure. Possible pathogenic mechanisms are briefly discussed. A consequence of such an experience is that magnetic resonance imaging or computed tomography scans should be made of every patient with uncommon extrapyramidal disorders, particularly if they do not respond to drug therapy.

[Zinc and lymphocyte subsets in patients with HIV infection]. / Zinco e assetto linfocitario in pazienti con infezione da HIV.

Serum zinc levels were assayed in patients with AIDS and related syndromes, using spectrophotometry and atomic absorption. Statistical data have shown that serum zinc levels, in addition to being significantly lower (p less than 0.001) among different groups and controls, decrease progressively with the worsening of the clinical and immunological picture from LAS to AIDS. Serum zinc levels in patients with AIDS and ARC have, moreover, been demonstrated to be related (r = 0.8240; p less than 0.001) to the lymphocyte subset CD4 helper-induced. These results suggest that serum zinc determination and possibly zinc therapy might be reasonably considered in the management of patients with symptoms of HIV infection.

Clinical assessment of a novel antiadhesion barrier gel: prospective, randomized, multicenter, clinical trial of ADCON-L to inhibit postoperative peridural fibrosis and related symptoms after lumbar discectomy.

A prospective, multicenter, randomized, double-blind, controlled study of ADCON-L Anti-Adhesion Barrier Gel (a medical device by Gliatech Inc, Cleveland, OH) was conducted in 298 patients undergoing first-time lumbar discectomy to evaluate the safety and effectiveness of ADCON-L in preventing postoperative peridural fibrosis and in improving patient clinical outcome. After lumbar discectomy, patients were randomized to receive either ADCON-L gel or nothing (control group) at the conclusion of the surgical procedure. Six months after surgery, peridural scar was evaluated by magnetic resonance imaging, and postoperative pain and straight-leg-raise angle were assessed. No statistically significant differences between the ADCON-L and control groups were observed in terms of adverse events or wound healing characteristics. ADCON-L gel was shown to be safe and to significantly inhibit peridural scar compared with the control group (P = 0.002). That peridural scarring was reduced with ADCON-L gel was further supported by direct visualization of scar tissue at reoperation in both groups. ADCON-L-treated patients had better clinical outcomes than did control patients. The incidence of activity-related pain was significantly reduced (P = 0.013), straight-leg-raise examination scores were significantly improved (P = 0.024 on the operative side and P = 0.015 on the nonoperative side), and ADCON-L reduced low back pain when it was most severe (P = 0.047) and at the end of the day (P = 0.044).

Lumbago and radicular complaints: not always a disc hernia or degenerative stenosis of the spinal canal. A differential diagnosis of infrequent diseases.

Low back ache and pain in the legs are not always due to disc displacement and lumbar spinal degenerative changes. Some infrequent, but really not very rare diseases are presented in order to avoid mistakes which can have serious consequences for the patients. Degenerative changes of the lumbar spine are very common, not only in aged people. A superficial examination of the patient with back ache and/or pain in the legs can lead to a fallacious tie-up between such lesions and disturbances and complaints which are not connected to them.

Anterior cervical discectomy without fusion in cervical disc herniation with radicular complaints.

Only cervical disc herniation that provokes root compression unresponsive to conservative treatment should be selected for operation. The operative technique must allow adequate removal of the disc and relieve any root pressure without distressing the patient. Operative decompression of the root can be attained via laminectomy and arthrotomy or by way of an anterior approach. With this second procedure, the ventral discectomy can be done in conjunction with an interbody fusion. We report our experience with 216 patients who unterwent anterior cervical microsurgical discectomy without fusion between 1980 and 1944. All these patients were suffering from compressive cervical radiculopathy caused by disc displacement without significant degenerative deformation of the motion segment and without manifest segmental instability. The follow-up ranged between 6 and 185 months (average 71 months) in the 175 patients in whom it was possible. Only in 7 patients (4 %) is the result unsatisfactory; 79 patients (45 %) are completely free of symptoms 99; (56.6 %) are very satisfied and 45 (25.7 %) satisfied with the result of the procedure.

[Pathophysiology of vertebrogenic lumbar and leg pain (pain, sensory disorders, paralysis): review related to clinical aspects]. / Pathophysiologie der vertebragenen Kreuz- und Beinbeschwerden (Schmerzen, Sensibilitätsstörungen, Paresen): klinikbezogene Ubersicht.

Vertebrogenic pain is attached to several types of spinal pathology: degenerative diseases of spinal structures, disc displacement with or without radicular disturbances, primary or metastatic tumors, inflammatory diseases. Present views on the pathogenetic mechanisms of the various types of vertebrogenic local radicular and pseudoradicular pain are discussed. Current opinions about pathogenesis of radicular deficit of sensibility and physical force are also presented.

[Consciousness and self-consciousness as biological phenomena]. / Bewusstsein und Selbstbewusstsein als biologische Phänomene.

Can there be a generally accepted account of consciousness? Consciousness is the main aspect of the mind-body problem and has intrigued man since he achieved the awareness of his own existence and identity, i.e. since he became self-conscious. The topic of consciousness spans the efforts of the humanist and naturalist, psychological, theological and physiological thinking and research. During the last years an upsurge of both neurophysiological and philosophical interest has tried to outline the place of consciousness and self-consciousness in the order of nature. 'Without consciousness, the mind-body problem would be much less interesting. With consciousness it seems hopeless', Nagel (16) wrote. Our thesis, supported by a significant part of today's epistemology (which takes up the believes of several main physiologists from the last century up to now), is that the question of consciousness and the mind-body problem are systematically and scientifically insoluble because the mind is fated to remain intrinsically mysterious to us. Thus, even though consciousness and self-consciousness belong to the intrinsic characteristics of our everyday life and experience, they seem to remain indefinable and mysterious and, therefore, to fall outside the scope of rational inquiry, defying both scientific and philosophical investigation. This assumption does not mean that neurophysiological sciences are unfeasible, but it is just an inquiry into their methodologic and cognitive limits.

[Lumbar intervertebral disk disease and its sequelae: segmental instability, intervertebral disk displacement, lumbar spinal stenosis--change in a common disease]. / Das lumbale Bandscheibenleiden und seine Folgen: segmentale Instabilität, Bandscheibenvorfall, lumbale Wirbelstenose--Wandel eines Volksleidens.

Clinical, radiological, surgical and experimental experiences allow to construct a theory of degeneration of the lumbar spine, which explains the pathogenesis of spondylosis, stenosis and disc displacement as well. The centre of the whole process is the segmental instability due to disc derangement. Several partially new criteria for a rational surgical and conservative therapy follow from such theory, which we try to explain by some exemplaric cases. Finally, we describe shortly own surgical procedure for combined operation of decompression and lumbar fusion.

[Acute lumbago. Guidelines for clinical practice]. / Die akute Lumbago. Ein Leitfaden für die Praxis.

Acute low-back pain without sciatica, with some spread of discomfort to the region of the sacroiliac joint, to the outer part of the buttock as well as to the lateral and the back part of the thigh, is a unifying symptom of a very common clinical syndrome whose exact underlying cause remains often uncertain. Most patients fall then into the category of nonspecific low-back pain. Probably the pathogenesis is not uniform, and the pain can arise from a variety of structures (muscles, ligament, spine). Pain which persists after 3 to 4 days should warn the clinician that a serious pathological condition may be present which requires a new approach to diagnosis and treatment.

[Ilio-inguinal and genito-femoral neuralgia. Causes, clinical aspects, therapy]. / Die Ilioinguinalis- und Genitofemoralisneuralgie. Ursachen, Klinik, Therapie.

Entrapment neuropathy of the ilioinguinal and of the genito-femoral nerves is a rare but sometimes very painful complication of abdominal surgery (herniorrhaphy, appendectomy, nephrectomy, gynecological surgery, removal of bone from the inner table of the iliac crest, etc.). Sometimes symptoms develop during a normal pregnancy or delivery. Spontaneous entrapment of the ilioinguinal nerve as it passes through the Mm. obliquus internus and transversus abdominis has also been observed. We have operated such a case. The causes, features and the associated findings of entrapment neuropathy of the two nerves are pointed out. In the frequent cases attributable to previous surgery the retroperitoneal resection of the nerves is advocated instead of a local revision, which is usually unsuccessful due to the impossibility of finding and restoring the fine nerves in a dense scar.

[Meralgia paresthetica. Pathogenesis, clinical aspects and therapy of compression of the lateral cutaneous nerve of the thigh]. / Die Meralgia paraesthetica. Pathogenese, Klinik und Therapie der Kompression des Nervus cutaneus femoris lateralis.

The lateral femoral cutaneus nerve is vulnerable to entrapment neuropathy where the nerve passes through the lateral end of the inguinal ligament. At the end of last century the clinical manifestation of this condition has been termed Meralgia paresthetica. It is a syndrome of pain, numbness, itching or other dysesthesias in the anterolateral aspect of the thigh, where perception of pinprick and touch often is diminished or lost. 36 patients were operated upon over a period of 17 years. After a short historical review, pathogenesis, clinical aspects and therapy of the syndrome are discussed. The correct surgical therapy is not the resection of the nerve, but its decompression, similar to the therapy of the entrapment of the median nerve at the wrist.

[Clinical aspects, pathophysiology and surgical treatment of lumbar spinal stenosis]. / Klinik, Pathophysiologie und chirurgische Behandlung der lumbalen Wirbelkanalstenose.

All the forms of spinal stenosis and spondylosis and some cases of lumbar disc displacement are considered as part of a degenerative process with a starting point in regressive changes of the disc. This leads to instability of the motion segment, which explains the dynamics of the pathophysiology and of the troubles of lumbar spinal stenosis, including the intermittent neurogenic claudication. Signs, symptoms and radiological findings of the unstable lumbar spine relating to spinal stenosis are discussed. Finally, we point out that the right surgical procedure has to solve the disturbances of root-compression and unstable spine as well. We describe a procedure which we prefer as the safest and most efficient, using selected decompression and translaminar joint screws.