Effects of Intermittent Femoral Nerve Injections of Bupivacaine, Levobupivacaine, and Ropivacaine on Mitochondrial Energy Metabolism and Intracellular Calcium Homeostasis in Rat Psoas Muscle

Background: Long-acting local anesthetics cause muscle damage. Moreover, long-acting local anesthetics act as uncoupler of oxidative phosphorylation in isolated mitochondria and enhance sarcoplasmic reticulum Ca2+ release. The aim of the study was to evaluate effects of perineural injections of local anesthetics on mitochondrial energetic metabolism and intracellular calcium homeostasis in vivo.

Methods: Femoral nerve block catheters were inserted in adult male Wistar rats. Rats were randomized and received seven injections (1 ml/kg) of bupivacaine, levobupivacaine, ropivacaine, or isotonic saline at 8-h intervals. Rats were killed 8 h after the last injection. Psoas muscle was quickly dissected from next to the femoral nerve. Local anesthetic concentrations in muscle were determined. Oxidative capacity was measured in saponin-skinned fibers. Oxygen consumption rates were measured, and mitochondrial adenosine triphosphate synthesis rate was determined. Enzymatic activities of mitochondrial respiratory chain complexes were evaluated. Local calcium release events (calcium sparks) were analyzed as well as sarcoplasmic reticulum calcium content in saponin-skinned fibers.

Results: Eight hours after the last injection, psoas muscle concentration of local anesthetics was less than 0.3 [mu]g/g tissue. Adenosine triphosphate synthesis and adenosine triphosphate-to-oxygen ratio were significantly decreased in the muscle of rats treated with local anesthetics. A global decrease (around 50%) in all of the enzyme activities of the respiratory chain was observed. Levobupivacaine increased the amplitude and frequency of the calcium sparks, whereas lower sarcoplasmic reticulum calcium content was shown.     

Retrospective patient outcome evaluation after semi-rigid stabilization without fusion for degenerative lumbar instability

Postero-lateral fusion by means of rod-and-screws/hooks constructs is still the gold standard in the treatment of lumbar degenerative spinal diseases. However, fusion remains fraught with a high risk of adjacent levels degeneration, sometimes leading to suboptimal clinical outcomes. Dynamic stabilization is supposed to compensate for disadvantages associated with rigid fusion. Preliminary results of spinal stabilization by means of dynamic devices show encouraging results. Therefore, the aim of the present study is to retrospectively evaluate the overall long term outcome and the condition of the adjacent discs to fused segments in an active population of 33 patients with back pain associated with lumbar instability, who underwent postero-lateral dynamic stabilization by means of a dynamic rod-and-screws construct, without fusion. The mean follow-up was 45 months. Clinical and radiological data, pain, function, return to work rate and patient satisfaction index were recorded to assess the overall patient outcome. The results show a very low rate of post-operative complications. No spontaneous fusion was noted in any patient. Pain, both lumbar and radicular, was totally relieved in most of the patients and the functional results were good or excellent in 76% of patients. Most of the patients resumed their previous activities; the return to previous work rate was 87.5%. Ninety-four percent of the patients were fully satisfied with the results. The preservation of both instrumented levels and the adjacent ones was observed in 90% of patients. Although the present series is rather limited in number, the results of the study are encouraging and in agreement with most findings in the literature. As the results are sustained at a mid and long term, the authors believe that the stabilization without fusion by means of semi-rigid/dynamic systems is an interesting alternative to classical fusion as long as the indications are strictly defined.     

Long-term outcomes evaluation after pars defect repair in adult low-grade isthmic spondylolithesis

Adult low-grade isthmic spondylolisthesis is often treated by posterolateral lumbar fusion (PLF), with a certain rate of complications and non-return to work. Alternatives to fusion, like pars defect repair (PDR), were used with encouraging results in young populations and athletes but their outcomes were rarely evaluated for adult patients. This retrospective study quantitatively analysed the long-term outcomes in adult isthmic spondylolisthesis patients treated by PLF or PDR. At a mean follow-up of 9 years, clinical, socio-professional, radiological data and Stauffer-Coventry score were available for 59 patients (39 cases treated by PLF and 20 treated by PDR). The overall clinical outcomes were comparable in both populations (88% in the PDR and 80% in PLF group 1), with a larger proportion of excellent results (56% vs. 10%) and of return to work in the PDR group. Radiological quantitative analysis highlighted stationary evolution and comparable outcomes for the two groups, except for vertebral slip evolution and adjacent level degeneration rate. Abnormal kinematic patterns outlined for PLF patients 20% of pseudarthrosis and 42% of adjacent levels hypermobility and for PDR ones low mobility for the levels adjacent to instrumented vertebra in 40% of cases. Quantified analysis of biomechanical parameters interpreted altogether with clinical outcome, complications and economic burden of the patient, provided accurate objective data for a better appreciation of global outcome, allowing for a preliminary view on long-term outcomes after PDR in adult low-grade isthmic spondylolisthesis, which were not presented in literature until now.     

Hepatic stellate cell activation in liver transplant patients with hepatitis C recurrence and in non-transplanted patients with chronic hepatitis C.

The pathogenic mechanisms of accelerated graft fibrosis in hepatitis C recurrence after liver transplantation (LT) are not well established. The aim of the study was to assess whether a greater activation of hepatic stellate cells (HSC), the major collagen-producing cells in the liver, can occur in these patients as compared to non-LT patients with chronic hepatitis C. We determined the amount of activated HSC by computer-based morphometric analysis of alpha-smooth muscle actin (alphaSMA)-positive cells and the hepatic TGFbeta(1) expression by immunohistochemistry in 46 LT patients with hepatitis C recurrence, 35 non-LT patients with chronic hepatitis C, and 16 controls. Hepatic alphaSMA and TGFbeta(1) expression was higher in LT patients with hepatitis C recurrence than in controls and was correlated with fibrosis stage and progression rate. No significant difference in alphaSMA and TGFbeta(1) expression was observed between LT and non-LT patients with hepatitis C, with the exception of a higher transforming growth factor beta-1 (TGFbeta(1)) expression in non-LT patients in the early stages of fibrosis. LT patients receiving cyclosporine (CsA) or tacrolimus (FK) had a similar fibrosis progression rate and alphaSMA and TGFbeta(1) expression. In conclusion, the accelerated fibrosis observed in LT patients with hepatitis C recurrence does not seem to be related to a greater amount of activated HSC and TGFbeta(1) expression in the grafts of these patients as compared to non-LT patients with chronic hepatitis C. In LT patients, the amount of activated HSC and TGFbeta(1) expression correlated with fibrosis stage and progression, without any apparent influence of the type of calcineurin inhibitor administered.     

Erfahrungen anlässlich des Expertenpanels „Fußball-WM Deutschland – Medical Lessons Learned“, 06.10.2006, München

Ohne Zusammenfassung     

Does age worsen EEG slowing and attention deficits in obstructive sleep apnea syndrome?

OBJECTIVE: The aim of this study was to determine whether EEG slowing is more pronounced in older than younger OSAS patients and to verify whether this cortical slowing is correlated to daytime performance, respiratory perturbation and sleep fragmentation. METHODS: Twelve young OSAS patients (mean age 38.2+/-2.0 y) and 13 older OSAS patients (mean age 62.2+/-1.9 y) along with 13 young controls (mean age 35.8+/-2.0 y) and 14 older controls (mean age 60.2+/-2.0 y) underwent a polysomnographic evaluation followed by a waking EEG recording. As a global index of cortical slowing, a ratio of slow-to-fast frequencies was calculated in all cortical regions. Daytime performance was assessed using the four choice reaction time test. RESULTS: Differences in waking EEG and in daytime performance were analyzed by ANOVAs with Group and Age as factors. Waking EEG did not yield a Group by Age interaction. OSAS patients had higher ratios across all regions than controls. Similarly, daytime performance revealed no Group by Age interaction. However, OSAS patients showed more lapses than controls and older subjects were slower than younger subjects. CONCLUSIONS: Our results indicate that age does not interact with OSAS to worsen the severity of cortical slowing, but age can add to the OSAS effect to worsen daytime performance deficits in OSAS patients. SIGNIFICANCE: The daytime performance deficits observed particularly in elderly OSAS patients warrant a careful clinical assessment of these patients to prevent accidents and injuries.