Somatosensory input in the context of transcranial magnetic stimulation coupled with electroencephalography: An evidence-based overview

The transcranial evoked potential (TEP) is a powerful technique to investigate brain dynamics, but some methodological issues limit its interpretation. A possible contamination of the TEP by electroencephalographic (EEG) responses evoked by the somatosensory input generated by transcranial magnetic stimulation (TMS) has been postulated; nonetheless, a characterization of these responses is lacking. The aim of this work was to review current evidence about possible somatosensory evoked potentials (SEP) induced by sources of somatosensory input in the craniofacial region. Among these, only contraction of craniofacial muscle and stimulation of free cutaneous nerve endings may be able to induce EEG responses, but direct evidence is lacking due to experimental difficulties in isolating these inputs. Notably, EEG evoked activity in this context is represented by a N100/P200 complex, reflecting a saliency-related multimodal response, rather than specific activation of the primary somatosensory cortex. Strategies to minimize or remove these responses by EEG processing still yield uncertain results; therefore, data inspection is of paramount importance to judge a possible contamination of the TEP by multimodal potentials caused by somatosensory input.

Precision pain management in interventional radiology

Pain is a common manifestation of several benign and malignant conditions. Inadequate response to conservative therapies is often succeeded by incremental use of analgesics and opioids; however, such an approach is often ineffective, not well tolerated by patients, and carries the risk of addiction leading to the opioid crisis. Implementing minimally invasive percutaneous procedures, performed by interventional radiologists has proven to be successful in providing safe, effective, and patient-specific therapies across a wide range of painful conditions. In the present narrative review, we will review the repertoire of minimally invasive imaging guided interventions, which have been successfully used to treat common painful benign and malignant conditions. We briefly describe each technique, common indications, and expected results.

PMR4-dependent cell wall depositions are a consequence but not the cause of temperature-induced autoimmunity

Plants possess a well-balanced immune system that is required for defense against pathogen infections. In autoimmune mutants or necrotic crosses, an intrinsic temperature-dependent imbalance leads to constitutive immune activation, resulting in severe damage or even death of plants. Recently, cell wall depositions were described as one of the symptoms following induction of the autoimmune phenotype in Arabidopsis saul1-1 mutants. However, the regulation and function of these depositions remained unclear. Here, we show that cell wall depositions, containing lignin and callose, were a common autoimmune feature and were deposited in proportion to the severity of the autoimmune phenotype at reduced ambient temperatures. When plants were exposed to reduced temperature for periods insufficient to induce an autoimmune phenotype, the cell wall depositions were not present. After low temperature intervals, sufficient to induce autoimmune responses, cell wall depositions correlated with a point of no return in saul1-1 autoimmunity. Although cell wall depositions were largely abolished in saul1-1 pmr4-1 double mutants lacking SAUL1 and the callose synthase gene GSL5/PMR4, their phenotype remained unchanged compared to that of the saul1-1 single mutant. Our data showed that cell wall depositions generally occur in autoimmunity, but appear not to be the cause of autoimmune phenotypes.

PMMA Bone Cement in Interventional Oncology

Polymethylmethacrylate (PMMA) bone cement is increasingly being used for percutaneous minimally invasive treatments of patients suffering from bone malignancies. PMMA is composed of a polymeric powder and a monomeric liquid. Once mixed, the polymerization process begins and leads to a viscous fluid that can be injected through a bone trocar. Cement progressively hardens within the bone, leading to a viscoelastic solid material. PMMA interacts with the surrounding cancellous bone through mechanical interlocking via interdigitations in trabecular bone. It can also bond with hardware, such as titanium screws, as it penetrates the macro- and micro-irregularities of the hardware. PMMA itself has no antineoplastic effects but may be used as a stand-alone treatment to provide pain palliation and bone consolidation through mechanical reinforcement, notably in areas with high compression load. It can also be used to reinforce the anchorage of screws in case of a landing zone with poor bone quality due to underlying malignant osteolysis.

Pain relief and local tumour control following percutaneous image-guided cryoablation for spine metastasis: a 12-year single-centre experience

AIM

To assess pain relief and local tumour control retrospectively in spinal metastases undergoing cryoablation.

MATERIALS AND METHODS

Between May 2008 and September 2020, 46 metastases in 41 consecutive patients (mean age 59.7±4.4 [SD] years; range 27-84) were treated with cryoablation in 42 interventional sessions. Patient demographics, procedural data, complications, pain, and local tumour control were analysed retrospectively.

RESULTS

Thirty-one patients (36 spine metastases; 32 sessions) were treated for pain relief and 10 (10 metastases; 10 sessions) for local tumour control. Clinical success was reached in 30/32 (93.8%) interventional palliative sessions. Mean pre-procedural numerical pain rate scale was 6.2±1.7 (SD), and dropped significantly to 3.5±1.8 (SD), 1.9±1.7 (SD), and 1.9±1.8 (SD) at 24-h, 1-month and at the last available follow-up (median 16.5±23.2 [SD] months), respectively. For patients requiring local tumour control, primary clinical success was reached in 6/10 (60%) spinal metastases at median 25-months follow-up. The overall complication rate was 8%, with no secondary fractures or iatrogenic thermal-mediated nerve injuries reported.

CONCLUSION

Percutaneous image-guided cryoablation of spinal metastases is safe and effective in achieving pain relief and local tumour control.

Robot-Assisted Bone Cement Injection

In this article, assistance to bone cement injection is studied, with a focus on vertebroplasty, a procedure dedicated to the treatment of vertebral compression fractures. A robotic system that can remotely be operated at pressures up to 140 bar is presented. It improves cement polymerization control, combining a cold passive exchanger that slows down the cement curing in the syringe and an active exchanger that controls the injected cement temperature. The cement remote injection uses a rate control teleoperation strategy with force feedback to help monitoring the cement state. In addition to laboratory assessments, cadaver experiments were performed to illustrate the satisfactory operation of the whole system.

Impact of old and very old age on outcomes in patients with acute ischemic stroke undergoing endovascular therapy

Background and purpose

Only a restricted number of elderly patients has been included in the majority of recent endovascular stroke trials. We provided an analysis about differences in outcomes after mechanical thrombectomy (MT) according to age.

Methods

A retrospective analysis of an observational registry of patients with anterior large vessel acute ischemic stroke was performed. Main analysis was performed comparing patients <80 vs. ≥80 years old. A sensitivity analysis was performed comparing 3 age groups: i) <80 years; ii) 80–84 years; iii) ≥85 years. Outcomes were: i) any hemorrhagic infarction; ii) alive with disability; iii) death; iv) a composite outcome of alive with disability/death.

Results

615 patients were identified. 227 (36.9%) patients were ≥80 years old, with 115 (18.5%) ≥85 years old. Elderly (≥80 years) patients showed a higher modified Rankin Scale (mRS) at discharge and 3-months follow-up (F=9.819, p=0.001) [Figure 1]. Comparing the three groups (<80 years, 80–84 years, ≥85 years) a progressively higher mRS was found at discharge and 3 months follow-up (F=4.899, p=0.008). A progressively higher rate of death and composite outcome between the age groups was found, both in the main and sensitivity analyses. In the logistic regression analysis age ≥80 years was found associated with an increased risk of death (odds ratio [OR]: 2.25, 95% confidence interval [CI]: 1.27–4.00) and showed a trend in higher risk for composite outcome (OR: 1.61, 95% CI: 0.92–2.281). No difference was found between 80–84 years and <80 years patients, while very elderly (≥85 years) had an increased risk of death (OR: 2.85, 95% CI: 1.60–5.10) and composite outcome (OR: 2.37, 95% CI: 1.30–4.33).

Conclusions

In our analysis elderly patients have an increased risk of death and composite outcome of disability and death. In particular, this risk appears to be significantly higher in very elderly patients (≥85 years old).

Figure 1. mRS according to main analysis

Funding Acknowledgement

Type of funding source: None

Attitudes to dental visits in a child population attending public dental health care in Jönköping, Sweden-trends over 40 years

PURPOSE

To study attitudes to dental visits in a child population attending public dental health care between 1973 and 2013.

METHODS

Random samples of individuals aged 3, 5, 10, 15 and 20 years took part in cross-sectional studies based on clinical parameters and a questionnaire, all repeated every 10 years using the same study design. One question related to dental attitude; "What do you feel at the prospect of an appointment with a dentist?". The affirmative answers were full of expectation, unaffected, ill at ease, frightened and sick, representing positive, neutral and negative attitudes. During the same 40-year period, a dental health care system based on prevention and regular dental appointments was reinforced.

RESULTS

In preschool children, the most pronounced change was an increase in the number of children reporting full of expectation during the study period. In 10-, 15- and 20-year-olds, there was an increase in unaffected and a decrease in ill at ease over time. A reduction in frightened was only seen in the 20-year-olds.

CONCLUSIONS

Despite a simultaneous dramatic decline in caries and a reduced need for operative dental treatment, the dental attitudes were fairly constant during the 40-year period. The moderate shifts to more positive or neutral dental attitudes were merely seen during the first 10 or 20 years. After this, the changes in answers were limited. This leads to the assumption that factors other than dental treatment experiences have an impact on dental attitudes in children.

Efficacy of Parent-Infant-Psychotherapy with mothers with postpartum mental disorder: study protocol of the randomized controlled trial as part of the SKKIPPI project

BACKGROUND

After the birth of a child, many mothers and fathers experience postpartum mental disorders like depression, anxiety, obsessive-compulsive disorder, stress or other illnesses. This endangers the establishment of a secure attachment between the children and their primary caregivers. Early problems in parent-child interaction can have adverse long-term effects on the family and the child's well-being. In order to prevent a transgenerational transmission of mental disorders, it is necessary to evaluate psychotherapeutic interventions that target psychologically burdened parents of infants or toddlers. The aim of this trial is to investigate the efficacy of Parent-Infant-Psychotherapy (PIP) for mothers with postpartum mental disorder and their infants (0-12 months).

METHODS/DESIGN

In this open, randomized controlled intervention trial 180 mother-infant-dyads will be included and randomly allocated to 12 sessions of PIP or care as usual. The interventions take place either in inpatient adult psychiatric departments or in outpatient settings with home visits. The primary outcome is the change in maternal sensitivity assessed by the Sensitivity subscale of the Emotional Availability Scale (EAS) through videotaped dyadic play-interactions after 6 weeks. Secondary outcomes are maternal psychopathology, stress, parental reflective functioning, infant development and attachment after 6 weeks and 12 months. In addition, maternal attachment (AAI) and reflective functioning (AAI) will be analyzed as potential moderators, and resource usage in the German health system as well as associated costs will be evaluated.

DISCUSSION

There is increasing demand for well-controlled studies on psychotherapeutic interventions in the postpartum period that do not only focus on particular risk groups. This randomized controlled trial (RCT) represents one of the first studies to investigate the efficacy of PIP in inpatient psychiatric departments and outpatient care centers in Germany. The results will fill knowledge gaps on the factors contributing to symptom reduction in postpartum mental disorders and improvements in mother-child relationships and help in developing preventive and therapeutic strategies for the fragmented German health care system.

TRIAL REGISTRATION

German Register for Clinical Trials, ID: DRKS00016353.

4329Mega-studies in heart failure, effect dilution in examination of new therapies

Aims

All phase 3 studies in patients with acute heart failure (AHF) and HF with preserved ejection fraction (HFpEF) have failed in the last decades. We explore the likelihood that the negative results are due to chance and/or to study size and dilution of statistical power.

Methods and results

First, using simulations, we examined the probability that a positive finding in phase 2 would result in studying truly effective drugs in phase 3. We simulated phase 2 studies under six scenarios where the range of true relative risk (RR) for an outcome of interest varied from 0.5 (major benefit) to 1.15 (some harm). The proportion of simulated studies where the RR <0.8 (we assumed that a 20% or greater risk reduction reflects an effective drug) ranged from 6% to 42% across the six scenarios studied. To further simulate “real life” clinical research, we simulated a continuous surrogate outcome that was linearly related to the true RR in each simulation of each scenario. Regardless of criteria considered for a positive phase 2 trial, results suggest that even in our worst-case scenario, where overall only 6% of drugs taken into phase 2 are effective, roughly 20% of phase 3 studies, if appropriately powered, should have yielded positive results. Given this, we then explored study size in AHF research, as a potential explanation for the high failure rate in these studies. Comparison of published phase 2 and 3 clinical trials with registries in AHF suggest that populations in both large and small trials differ from “real life”. Meta-regression models suggest that both control event rates, and in the serelaxin program as an example, treatment effects, decline with increasing study size greatly reducing power (figure). This effect dilution might be explained by an increasing proportion of patients enrolled in studies who cannot benefit from the study drug.

Figure 1. Power at two-sided 0.05 significance level to detect an effect size of hazard ratio of 0.65 (left) or 0.8 (right) with a placebo event rate of 10% (top) and 20% (bottom) at N=100 at various treatment effect dilutions with increasing sample size.

Conclusion

These data suggest that it is unlikely that the very high rate of negative AHF phase III trials can be explained by chance alone. Potentially, our tendency to increase sample size does not necessarily increase statistical power, due to more heterogenous populations leading to reduced event rates and treatment effects.

Transforaminal Insertion of a Thermocouple on the Posterior Vertebral Wall Combined with Hydrodissection during Lumbar Spinal Radiofrequency Ablation

The purpose of the present article is to describe the technique of transforaminal insertion of an ultrathin thermosensor in the anterior epidural space in 13 patients treated by radiofrequency ablation. The mean time taken to position the thermosensor was 10.6 minutes (range, 5-38 minutes). Technical success was 93% (correct positioning in 13/14 levels). Additional hydrodissection was performed through the same access in 11 cases. No postoperative neural deficit was elicited in any of the cases.

Percutaneous extra-spinal cementoplasty in patients with cancer: A systematic review of procedural details and clinical outcomes

PURPOSE

To perform a systematic review of technical details and clinical outcomes of percutaneous extra-spinal cementoplasty in patients with malignant lesions.

MATERIALS AND METHODS

PUBMED, MEDLINE, MEDLINE in-process, EMBASE and the Cochrane databases were searched between January 1990 and February 2019 using the keywords «percutaneous cementoplasty», «percutaneous osteoplasty» and «extra-spinal cementoplasty». Inclusion criteria were: retrospective/prospective cohort with more than 4 patients, published in English language, reporting the use of percutaneous injection of cement inside an extra-spinal bone malignant tumour using a dedicated bone trocar, as a stand-alone procedure or in combination with another percutaneous intervention, in order to provide pain palliation and/or bone consolidation.

RESULTS

Thirty articles involving 652 patients with a total of 761 lesions were reviewed. Mean size of lesion was 45mm (range of mean size among publications: 29-73mm); 489 lesions were located in the pelvis, 262 in the long bones of the limbs and 10 in other locations. Cementoplasty was reported as a stand-alone procedure for 60.1% of lesions, and combined with thermal ablation for 26.2% of lesions, implant devices for 12.3% of lesions, and balloon kyphoplasty for 1.4% of lesions. The mean volume of injected cement was 8.8mL (range of mean volume among publications: 2.7-32.2mL). The preoperative visual analogic scores ranged between 3.2 and 9.5. Postoperative scores at last available follow-up ranged from 0.4 to 5.6. Thirteen papers reported a reduction of the visual analogic scores of 5 points or more. Nerve injury was the most frequent symptomatic leakage (0.6%).

CONCLUSION

Percutaneous extra-spinal cementopasty is predominantly performed as a stand-alone procedure and for lesions in the bony pelvis. It appears to be an effective tool to manage pain associated with malignant bone tumours. There is however a lack of standardization of the technique among the different publications.

Preclinical evaluation of the atraumatic nature of a spring loaded blunt tip coaxial needle in a swine model

PURPOSE

To test in vivo in an animal model the inherent atraumatic characteristics of the spring loaded blunt tip of a coaxial needle (Gangi-SoftGuard®, Apriomed, Sweden) against a conventional sharp stylet coaxial needle.

MATERIAL AND METHODS

The study was conducted on a 40kg male swine that was its own control for a vascular trauma model. The procedure consisted of voluntary attempts to transfix and traverse the artery/aorta under continuous real-time angiogram. Test and control needles were positioned in the region of the intercostal, superior mesenteric and femoral/deep femoral arteries, and in the aorta. Computed tomography (CT) angiogram was performed post trauma to check for bleeding in the form of extravasation of contrast material. One attempt was performed per site and needle, except for the intercostal artery where a second attempt was done with the test needle, resulting in a total of 4 and 5 tests for the control and test needles, respectively.

RESULTS

With the spring loaded blunt tip, no vascular trauma or bleeding was noted in the intercostal, superior mesenteric and femoral arteries, nor in the aorta. Vascular spasm that recovered with time was noted during the second attempt to transfix the same intercostal artery. There were consistent vascular traumas and bleedings with the control needle in all three tested arteries and the aorta, confirmed on angiogram as well as CT angiogram.

CONCLUSION

The atraumatic feature offered by the spring loaded blunt tip prevented vascular trauma during the 5 attempts made to transfix the artery/aorta in a swine.

Genetic relationship between poultry and wild bird viruses during the highly pathogenic avian influenza H5N6 epidemic in the Netherlands, 2017-2018

In the Netherlands, three commercial poultry farms and two hobby holdings were infected with highly pathogenic avian influenza (HPAI) H5N6 virus in the winter of 2017-2018. This H5N6 virus is a reassortant of HPAI H5N8 clade 2.3.4.4 group B viruses detected in Eurasia in 2016. H5N6 viruses were also detected in several dead wild birds during the winter. However, wild bird mortality was limited compared to the caused by the H5N8 group B virus in 2016-2017. H5N6 virus was not detected in wild birds after March, but in late summer infected wild birds were found again. In this study, the complete genome sequences of poultry and wild bird viruses were determined to study their genetic relationship. Genetic analysis showed that the outbreaks in poultry were not the result of farm-to-farm transmissions, but rather resulted from separate introductions from wild birds. Wild birds infected with viruses related to the first outbreak in poultry were found at short distances from the farm, within a short time frame. However, no wild bird viruses related to outbreaks 2 and 3 were detected. The H5N6 virus isolated in summer shares a common ancestor with the virus detected in outbreak 1. This suggests long-term circulation of H5N6 virus in the local wild bird population. In addition, the pathogenicity of H5N6 virus in ducks was determined, and compared to that of H5N8 viruses detected in 2014 and 2016. A similar high pathogenicity was measured for H5N6 and H5N8 group B viruses, suggesting that biological or ecological factors in the wild bird population may have affected the mortality rates during the H5N6 epidemic. These observations suggest different infection dynamics for the H5N6 and H5N8 group B viruses in the wild bird population.

Innervation of flexor hallucis longus muscle: an anatomical study for selective neurotomy

BACKGROUND

The aim of the study was to describe the innervation of flexor hallucis longus (FHL) and obtain its surgical coordinates to facilitate selective neurotomy.

MATERIALS AND METHODS

Fifteen embalmed lower limbs of adults were studied. Anatomical dissections to isolate the innervating branches of FHL were performed. Distance between the supplying nerve of FHL, including both its origin and termination, and the medial malleolus were obtained, providing anatomical coordinates beneficial for surgery.

RESULTS

In all cases, FHL was innervated by only one branch, which originated from the tibial nerve. Mean distance between the medial malleolus and the nervous branch origin was 21.39 ± 3.05 cm. Mean distance between the medial malleolus and the nervous branch termination was 12.7 ± 1.59 cm. Length of the nervous branch innervating FHL was proportional to the length of the leg, measuring 8.69 ± 2.45 cm. All nerves were located 15-17.4 cm above the medial malleolus.

CONCLUSIONS

This anatomical study traced valuable surgical coordinates useful for performing selective peripheral neurotomy on the nerve branch innervating the FHL.

Age-related changes in brain deactivation but not in activation after motor learning

It is poorly understood how healthy aging affects neural mechanisms underlying motor learning. We used blood-oxygen-level dependent (BOLD) contrasts to examine age-related changes in brain activation after acquisition and consolidation (24 h) of a visuomotor tracking skill. Additionally, structural magnetic resonance imaging and diffusion tensor imaging were used to examine age-related structural changes in the brain. Older adults had reduced gray matter volume (628 ± 57 ml) and mean white matter anisotropy (0.18 ± 0.03) compared with young adults (741 ± 59 ml and 0.22 ± 0.02, respectively). Although motor performance was 53% lower in older (n = 15, mean age 63.1 years) compared with young adults (n = 15, mean age 25.5 years), motor practice improved motor performance similarly in both age groups. While executing the task, older adults showed in general greater brain activation compared with young adults. BOLD activation decreased in parietal and occipital areas after skill acquisition but activation increased in these areas after consolidation in both age groups, indicating more efficient visuospatial processing immediately after skill acquisition. Changes in deactivation in specific areas were age-dependent after consolidating the motor skill into motor memory. Young adults showed greater deactivations from post-test to retention in parietal, occipital and temporal cortices, whereas older adults showed smaller deactivation in the frontal cortex. Since learning rate was similar between age groups, age-related changes in activation patterns may be interpreted as a compensatory mechanism for age-related structural decline.

CT Angiography ASPECTS Predicts Outcome Much Better Than Noncontrast CT in Patients with Stroke Treated Endovascularly

BACKGROUND AND PURPOSE

Noncontrast CT ASPECTS has been investigated as a predictor of outcome in patients with acute ischemic stroke. Our purpose was to investigate whether CTA source images are a better predictor of clinical and radiologic outcomes than NCCT ASPECTS in candidates for endovascular stroke therapy.

MATERIALS AND METHODS

CT scans of patients (n = 124) were independently evaluated by 2 readers for baseline NCCT and CTA source image ASPECTS and for follow-up ASPECTS. An mRS of ≤2 at 3 months was considered a favorable outcome. Receiver operating characteristic curve analysis was used to assess the ability of NCCT and CTA source image ASPECTS to identify patients with favorable outcomes. A stepwise multiple regression analysis was performed to find independent predictors of outcome.

RESULTS

Baseline CTA source image ASPECTS correlated better than NCCT ASPECTS with follow-up ASPECTS (r = 0.76 versus r = 0.51; P for comparison of the 2 coefficients < .001). Receiver operating characteristic curve analysis showed that baseline CTA source image ASPECTS compared with NCCT ASPECTS can better identify patients with favorable outcome (CTA source image area under the curve = 0.83; 95% CI, 0.76-0.91; NCCT area under the curve = 0.67; 95% CI, 0.58-0.77; P < .001). Finally, the stepwise regression analysis showed that lower age, good recanalization, lower time to recanalization, and good baseline CTA source image ASPECTS, not NCCT ASPECTS, were independent predictors of favorable outcome.

CONCLUSIONS

CTA source image ASPECTS predicts outcome better than NCCT ASPECTS; this finding suggests CTA rather than NCCT as a main step in the decision-making process for patients with acute ischemic stroke.

Preclinical pilot study monitoring topical drug penetration and dermal bioavailability of a peptidase inhibitor from different galenic formulations into pig dermis, using cutaneous microdialysis

BACKGROUND

Cutaneous microdialysis (CM) is an ex vivo technique that allows study of tissue chemistry, including bioavailability of actual tissue concentration of unbound drug in the interstitial fluid of the body.

AIM

To test the penetration and dermal bioavailability of galenic formulations of the small-molecule IP10.C8, a dual-protease inhibitor of the dipeptidyl peptidase and aminopeptidase families.

METHODS

Using CM, we tested the penetration and dermal bioavailability of IP10.C8 into the dermis and subcutis of pigs, and determined the tissue concentration of IP10.C8 enzymatically, using an enzyme activity assay (substrate Gly-Pro-pNA) and high performance liquid chromatography.

RESULTS

Dermal bioavailability was enhanced by using microemulsion or the addition of the penetration enhancer oleic acid to a hydroxyethylcellulose (HEC) gel formulation. Dermal bioavailability was also enhanced when galenic formulations were prepared with higher pH (7.5 vs. 6.5) or higher drug concentration (5% vs. 1%) in HEC gel.

CONCLUSION

It seems possible, using CM for topical skin penetration testing in anaesthetized domestic pigs, to test the bioavailability of newly designed drugs. However, the experimental time is limited due to the anaesthesia, and is dependent on drug recovery. Validation of this technique for routine use is challenging, and more experiments are needed to validate this preclinical set-up.

A role for NMDAR-dependent cerebellar plasticity in adaptive control of saccades in humans

BACKGROUND

Saccade pulse amplitude adaptation is mediated by the dorsal cerebellar vermis and fastigial nucleus. Long-term depression at the parallel fibre-Purkinjie cell synapses has been suggested to provide a cellular mechanism for the corresponding learning process. The mechanisms and sites of this plasticity, however, are still debated.

OBJECTIVE

To test the role of cerebellar plasticity phenomena on adaptive saccade control.

METHODS

We evaluated the effect of continuous theta burst stimulation (cTBS) over the posterior vermis on saccade amplitude adaptation and spontaneous recovery of the initial response. To further identify the substrate of synaptic plasticity responsible for the observed adaptation impairment, subjects were pre-treated with memantine, an N-methyl-d-aspartate receptor (NMDAR) antagonist.

RESULTS

Amplitude adaptation was altered by cTBS, suggesting that cTBS interferes with cerebellar plasticity involved in saccade adaptation. Amplitude adaptation and spontaneous recovery were not affected by cTBS when recordings were preceded by memantine administration.

CONCLUSION

The effects of cTBS are NMDAR-dependent and are likely to involve long-term potentiation or long-term depression at specific synaptic connections of the granular and molecular layer, which could effectively take part in cerebellar motor learning.

Cadaver study of anatomic landmark identification for placing ankle arthroscopy portals

BACKGROUND

Arthroscopy-assisted surgery is now widely used at the ankle for osteochondral lesions of the talus, anterior and posterior impingement syndromes, talocrural or subtalar fusion, foreign body removal, and ankle instability. Injuries to the vessels and nerves may occur during these procedures.

OBJECTIVE

To determine whether ultrasound topographic identification of vulnerable structures decreased the risk of iatrogenic injuries to vessels, nerves, and tendons and influenced the distance separating vulnerable structures from the arthroscope introduced through four different portals.

HYPOTHESIS

Ultrasonography to identify vulnerable structures before or during arthroscopic surgery on the ankle may be useful.

MATERIAL AND METHOD

Twenty fresh cadaver ankles from body donations to the anatomy institute in Strasbourg, France, were divided into two equal groups. Preoperative ultrasonography to mark the trajectories of vessels, nerves, and tendons was performed in one group but not in the other. The portals were created using a 4-mm trocar. Each portal was then dissected. The primary evaluation criterion was the presence or absence of injuries to vessels, nerves, and tendons. The secondary evaluation criterion was the distance between these structures and the arthroscope.

RESULTS

No tendon injuries occurred with ultrasonography. Without ultrasonography, there were two full-thickness tendon lesions, one to the extensor hallucis longus and the other to the Achilles tendon. Furthermore, with the anterolateral, anteromedial, and posteromedial portals, the distance separating the vessels and nerves from the arthroscope was greater with than without ultrasonography (P=0.041, P=0.005, and P=0.002), respectively; no significant difference was found with the anterior portal.

DISCUSSION

Preoperative ultrasound topographic identification decreases the risk of iatrogenic injury to the vessels, nerves, and tendons during ankle arthroscopy and places these structures at a safer distance from the arthroscope. Our hypothesis was confirmed.

LEVEL OF EVIDENCE

IV, cadaver study.

Effects of motor cortex rTMS on lower urinary tract dysfunction in multiple sclerosis

We tested the effects of 5-Hz rTMS over the motor cortex in multiple sclerosis (MS) subjects complaining of lower urinary tract symptoms either in the filling or voiding phase. Our data show that motor cortex stimulation for five consecutive days over two weeks ameliorates the voiding phase of the micturition cycle, suggesting that enhancing corticospinal tract excitability might be useful to ameliorate detrusor contraction and/or urethral sphincter relaxation in MS patients with bladder dysfunction. Multiple Sclerosis 2007; 13: 269–271. http://msj.sagepub.com

Real T1 relaxation time measurement and diurnal variation analysis of intervertebral discs in a healthy population of 50 volunteers

PURPOSE

To measure the real T1 relaxation time of the lumbar intervertebral discs in a young and healthy population, using different inversion recovery times, and assess diurnal variation.

MATERIAL AND METHODS

Intervertebral discs from D12 to S1 of 50 healthy volunteers from 18 to 25 years old were evaluated twice the same day, in the morning and in the late afternoon. Dedicated MRI sequences with different inversion recovery times (from 100 to 2500ms) were used to calculate the real T1 relaxation time. Three regions of interest (ROIs) were defined in each disc, the middle representing the nucleus pulposus (NP) and the outer parts the annulus fibrosus (AF) anterior and posterior. Diurnal variation and differences between each disc level were analyzed.

RESULTS

T1 mean values in the NP were 1142±12ms in the morning and 1085±13ms in the afternoon, showing a highly significant decrease of 57ms (p<0.001). A highly significant difference between the levels of the spine was found. The mean T1 of the anterior part of the AF was 577±9ms in the morning and 554±8ms in the afternoon. For the posterior part, the mean values were 633±8ms in the morning and 581±7ms in the evening. It shows a highly significant decrease of 23ms for the anterior part and 51ms for the posterior part (all p<0.001).

CONCLUSION

T1 mapping is a promising method of intervertebral disc evaluation. Significant diurnal variation and difference between levels of the lumbar spine were demonstrated. A potential use for longitudinal study in post-operative follow up or sport medicine needs to be evaluated.

Is anterior glenoid bone block position reliably assessed by standard radiography? A cadaver study

BACKGROUND

Standard radiography with an antero-posterior view and Bernageau's glenoid profile view is the method most widely reported in the literature to assess coracoid bone block position and fusion.

OBJECTIVE

The aim of this cadaver study was to determine whether the antero-posterior and Bernageau's radiographs provide a reliable and reproducible evaluation of the position of a coracoid bone block and its fixation screws.

METHOD

An isolated scapula showing no evidence of osteoarthritis or other abnormalities was used. The coracoid process was transferred to the anterior glenoid rim. Fixation was with two slightly diverging malleolar screws, chosen of different sizes for ease of identification. Computed tomography (CT) was performed as the reference imaging technique. The standard radiographs were then obtained, using fluoroscopy to accurately position the scapula for the antero-posterior and Bernageau's views. This position was defined as 0°, and radiographs were taken at angles of 5°, 10°, and 15° in all three planes. All radiographs were taken during a single session to ensure that the distance separating the tube from the scapula remained unchanged. The images were exported to OsiriX for analysis. We measured the angles formed by the screws and the glenoid surface, as well as bone block position and overhang. Finally, we used 1-mm thick disks to evaluate bone-to-bone contact.

RESULTS

No correlations were found between values by CT and by standard radiography (both views) for the screw angles or overhang. A space≤1mm between the neck of the scapula and the bone block was not visible on the standard radiographs in any of the positions.

CONCLUSION

Standard radiography does not provide an accurate analysis of bone block position or bone-to-bone contact. CT is needed to assess bone block and screw position and bone-to-bone contact.

LEVEL OF EVIDENCE

Level III.

Surgical Treatment of Iliofemoral Vein Thrombosis in Pregnancy

The incidence of deep leg vein thrombosis in pregnancy is estimated at 0.13 per 1000 to 1.4 per 100.1−3 One-third occur as isolated, descending iliofemoral vein thromboses, predominantly left-sided. We report our surgical experiences in venous thrombectomy with arteriovenous fistula (AV-fistula) in the groin between the superficial femoral artery and femoral vein in 29 gravidae with a mean age of 27.5 years (range 19–41 years). Thrombosis occurred between the 20th and 36th week of pregnancy. 25 were antepartum two postpartum and two postsectionem. An iliac spur was seen once, as was an AT III deficiency. At the beginning of our series AV-fistula was not performed in three patients who all suffered from re-thrombosis after 24 h. Re-thrombectomy with an AV-fistula was performed successfully. Three of the 26 gravidae with AV-fistula also developed re-thrombosis. In two patients re-thrombectomy was successful, in the third patient the common iliac vein could not be re-opened by thrombectomy and the functioning AF-fistula had been ligated because extensive vulval oedema had developed. Asymptomatic, late re-thrombosis occurred in two patients who were seen at outpatient follow-up. We have seen one mild, non-life-threatening pulmonary embolism on the first postoperative day. No further intraoperative nor postoperative or postpartum complications developed. The re-occlusion rate is 10.3% (3/29), the complication rate is 6.9% (2/29).

A Case Report: Pseudoangiomatous Stromal Hyperplasia Tumor Presenting as a Palpable Mass

We report a case of woman with a palpable lump on her left breast. On mammography, a huge mass located between the inner and the outer inferior breast quadrants of the left breast was found. The ultrasound examination realized later revealed a heterogeneous mass with smooth and lobulated borders. An MRI was also performed, showing an oval mass with heterogeneous areas of enhancement. Finally, a core biopsy under sonographic guidance revealed a pseudoangiomatous stromal hyperplasia of the breast.

Annual Cambial Rhythm in Pinus halepensis and Pinus sylvestris as Indicator for Climate Adaptation

To understand better the adaptation strategies of intra-annual radial growth in Pinus halepensis and Pinus sylvestris to local environmental conditions, we examined the seasonal rhythm of cambial activity and cell differentiation at tissue and cellular levels. Two contrasting sites differing in temperature and amount of precipitation were selected for each species, one typical for their growth and the other represented border climatic conditions, where the two species coexisted. Mature P. halepensis trees from Mediterranean (Spain) and sub-Mediterranean (Slovenia) sites, and P. sylvestris from sub-Mediterranean (Slovenia) and temperate (Slovenia) sites were selected. Repeated sampling was performed throughout the year and samples were prepared for examination with light and transmission electron microscopes. We hypothesized that cambial rhythm in trees growing at the sub-Mediterranean site where the two species co-exist will be similar as at typical sites for their growth. Cambium in P. halepensis at the Mediterranean site was active throughout the year and was never truly dormant, whereas at the sub-Mediterranean site it appeared to be dormant during the winter months. In contrast, cambium in P. sylvestris was clearly dormant at both sub-Mediterranean and temperate sites, although the dormant period seemed to be significantly longer at the temperate site. Thus, the hypothesis was only partly confirmed. Different cambial and cell differentiation rhythms of the two species at the site where both species co-exist and typical sites for their growth indicate their high but different adaptation strategies in terms of adjustment of radial growth to environmental heterogeneity, crucial for long-term tree performance and survival.