Compact steady-state tokamak performance dependence on magnet and core physics limits.

Compact tokamak fusion reactors using advanced high-temperature superconducting magnets for the toroidal field coils have received considerable recent attention due to the promise of more compact devices and more economical fusion energy development. Facilities with combined fusion nuclear science and Pilot Plant missions to provide both the nuclear environment needed to develop fusion materials and components while also potentially achieving sufficient fusion performance to generate modest net electrical power are considered. The performance of the tokamak fusion system is assessed using a range of core physics and toroidal field magnet performance constraints to better understand which parameters most strongly influence the achievable fusion performance. This article is part of a discussion meeting issue 'Fusion energy using tokamaks: can development be accelerated?'.

Higher-order mode suppression in twisted single-ring hollow-core photonic crystal fibers.

A hollow-core single-ring photonic crystal fiber (SR-PCF) consists of a ring of capillaries arranged around a central hollow core. Spinning the preform during drawing introduces a continuous helical twist, offering a novel means of controlling the modal properties of hollow-core SR-PCF. For example, twisting geometrically increases the effective axial propagation constant of the LP01-like modes of the capillaries, providing a means of optimizing the suppression of HOMs, which occurs when the LP11-like core mode phase-matches to the LP01-like modes of the surrounding capillaries. (In a straight fiber, optimum suppression occurs for a capillary-to-core diameter ratio d/D=0.682.) Twisting also introduces circular birefringence (to be studied in a future Letter) and has a remarkable effect on the transverse intensity profiles of the higher-order core modes, forcing the two-lobed LP11-like mode in the untwisted fiber to become three-fold symmetric in the twisted case. These phenomena are explored by means of extensive numerical modeling, an analytical model, and a series of experiments. Prism-assisted side-coupling is used to measure the losses, refractive indices, and near-field patterns of individual fiber modes in both the straight and twisted cases.

l-Lysine Acts as a Serotonin Type 4 Receptor Antagonist to Counteract In Vitro and In Vivo the Stimulatory Effect of Serotonergic Agents on Aldosterone Secretion in Man.

In the normal human adrenal gland, serotonin (5-HT) stimulates aldosterone secretion through the 5-HT4 receptor (5-HT4R). However, the physiological role of the serotonergic control of adrenocortical function is not known. In the present study, we have investigated the ability of l-Lysine, which has been shown to act as a 5-HT4 receptor antagonist, to counteract in vitro and in vivo the stimulatory effect of 5-HT4R agonists on aldosterone production. l-Lysine was found to inhibit aldosterone production induced by 5-HT and the 5-HT4R agonists BIMU8 from cultured human adrenocortical cells. The action of l-Lysine (4.95 g/day orally) on the adrenal cortex was also evaluated in 20 healthy volunteers in a double blind, cross-over, placebo controlled study. l-Lysine had no significant influence on basal plasma aldosterone levels and the aldosterone responses to upright posture, tetracosactide, and low sodium diet (10 mmol/day for 3 days). Conversely, l-Lysine significantly reduced the surge of plasma aldosterone induced by metoclopramide indicating that l-Lysine is able to efficiently antagonize the adrenal 5-HT4 receptors in vivo. These results suggest that l-Lysine supplementation may represent a new treatment of primary adrenal diseases in which corticosteroid hypersecretion is driven by overexpressed 5-HT4 receptors.

Non-thermal separation of electronic and structural orders in a persisting charge density wave.

The simultaneous ordering of different degrees of freedom in complex materials undergoing spontaneous symmetry-breaking transitions often involves intricate couplings that have remained elusive in phenomena as wide ranging as stripe formation, unconventional superconductivity or colossal magnetoresistance. Ultrafast optical, X-ray and electron pulses can elucidate the microscopic interplay between these orders by probing the electronic and lattice dynamics separately, but a simultaneous direct observation of multiple orders on the femtosecond scale has been challenging. Here we show that ultrabroadband terahertz pulses can simultaneously trace the ultrafast evolution of coexisting lattice and electronic orders. For the example of a charge density wave (CDW) in 1T-TiSe2, we demonstrate that two components of the CDW order parameter--excitonic correlations and a periodic lattice distortion (PLD)--respond very differently to 12-fs optical excitation. Even when the excitonic order of the CDW is quenched, the PLD can persist in a coherently excited state. This observation proves that excitonic correlations are not the sole driving force of the CDW transition in 1T-TiSe2, and exemplifies the sort of profound insight that disentangling strongly coupled components of order parameters in the time domain may provide for the understanding of a broad class of phase transitions.

A step towards cinacalcet testing for the diagnosis of primary hyperparathyroidism: comparison with the standardized intravenous calcium loading. A pilot study.

OBJECTIVE: A calcium load to suppress parathyroid hormone (PTH) secretion can help to perform the diagnosis in some case of primary hyperparathyroidism (PHPT) with atypical presentation. A similar test with calcimimetic, which avoids hypercalcaemia, would be of interest. Our proof of concept study was conducted to compare firstly the results of a single-dose cinacalcet testing with those of the standardized short-time calcium load in healthy control (HC) and secondly the results of the single-dose cinacalcet testing in HC and in PHPT. METHODS: Twelve HCs received in a random order, at a 2-week interval, either 0·33 mmol/kg calcium gluconate intravenously for 3 h, or a single oral dose of 30 mg or 60 mg cinacalcet. Twelve PHPTs received 30 mg cinacalcet and twelve other PHPTs 60 mg cinacalcet orally. Calcaemia and serum PTH levels were measured basally and then hourly for 6 h. RESULTS: In HC, plasma calcium did not significantly change after cinacalcet intake, whereas calcaemia rose up to 3·47 ± 0·05 mmol/l (mean ± SEM) at the end of the calcium load. PTH dropped from basal level to a similar extend (≥80%) with 60 mg cinacalcet and calcium load, whereas the decrease was significantly lesser (P < 0·01) with 30 mg cinacalcet. In PHPT, serum PTH levels dropped by 44·8 ± 6·9% and 58·2 ± 5·3% 1 h after the respective intake of 30 and 60 mg cinacalcet. One hour after the oral intake of 60 mg cinacalcet, serum PTH levels were <8 ng/l in HC and ≥8 ng/l in PHPT. CONCLUSION: Sixty milligrams of cinacalcet provides similar results as the standardized calcium load test; PHPT patients have a lower response to 60 mg cinacalcet than HC.

Three-dimensional drift kinetic response of high-ß plasmas in the DIII-D tokamak.

A quantitative interpretation of the experimentally measured high-pressure plasma response to externally applied three-dimensional (3D) magnetic field perturbations, across the no-wall Troyon ß limit, is achieved. The self-consistent inclusion of the drift kinetic effects in magnetohydrodynamic (MHD) modeling [Y. Q. Liu et al., Phys. Plasmas 15, 112503 (2008)] successfully resolves an outstanding issue of the ideal MHD model, which significantly overpredicts the plasma-induced field amplification near the no-wall limit, as compared to experiments. The model leads to quantitative agreement not only for the measured field amplitude and toroidal phase but also for the measured internal 3D displacement of the plasma. The results can be important to the prediction of the reliable plasma behavior in advanced fusion devices, such as ITER [K. Ikeda, Nucl. Fusion 47, S1 (2007)].

Rotation and kinetic modifications of the tokamak ideal-wall pressure limit.

The impact of toroidal rotation, energetic ions, and drift-kinetic effects on the tokamak ideal wall mode stability limit is considered theoretically and compared to experiment for the first time. It is shown that high toroidal rotation can be an important destabilizing mechanism primarily through the angular velocity shear; non-Maxwellian fast ions can also be destabilizing, and drift-kinetic damping can potentially offset these destabilization mechanisms. These results are obtained using the unique parameter regime accessible in the spherical torus NSTX of high toroidal rotation speed relative to the thermal and Alfvén speeds and high kinetic pressure relative to the magnetic pressure. Inclusion of rotation and kinetic effects significantly improves agreement between measured and predicted ideal stability characteristics and may provide new insight into tearing mode triggering.

Effect of transcranial magnetic stimulation on rectal sensitivity in irritable bowel syndrome: a randomized, placebo-controlled pilot study.

AIM: Repetitive transcranial magnetic stimulation (rTMS) applied to the motor cortex can induce analgesic effects in patients with chronic pain syndromes through its effect on central pain-modulatory systems. Our aim was to evaluate the effect of rTMS on rectal sensitivity in irritable bowel syndrome (IBS) patients. METHOD: In this randomized, sham-controlled, proof-of concept trial, 21 IBS patients (11 women and 10 men; mean age 44.0 ± 12.6 years) were randomized, using a double-blind crossover protocol, to active or sham rTMS for 5 days of treatment. The primary outcome was the increase in the pressure pain threshold after rTMS. Secondary outcomes were the changes in maximum tolerated rectal volume, rectal compliance and average pain intensity between baseline and the end of the treatments. RESULTS: There were no statistically significant differences between active and sham rTMS in terms of an increase in the pressure pain threshold, maximum tolerated volume and rectal compliance at the end of the treatments compared with baseline. However, in the subgroup of patients with the most marked rectal hypersensitivity, the volume threshold was significantly improved by active, but not by sham, rTMS (P = 0.03). Patients experienced a significant improvement in pain regardless of the type of stimulation. CONCLUSION: This pilot study failed to demonstrate any benefit of rTMS on our primary end-point. However, the effect of rTMS on rectal tolerated volume in the most hypersensitive patients was encouraging enough to plan more powered studies.

[Local consultations by specialists in urology: an answer to patients' expectations and dwindling physician numbers?]. / Les consultations avancées d'urologie peuvent-elles être une réponse satisfaisante aux attentes des patients et au problème de la démographie médicale?

OBJECTIVE: To analyze patients' views with regards to local consultations given by specialists in urology and to an offer of pre- and postoperative visits in the local general hospital with surgical interventions taking place at the university hospital. MATERIALS AND METHODS: An opinion survey by mail questionnaire was carried out in all 473 patients who had had a consultation with a specialist in two local general hospitals between November 2009 and April 2010. RESULTS: Response rate was 74%. Mean patient age was 65.5 ± 12 years [range, 20-90]. The reason for the consultation was cancer-related in 31.2% of patients. The majority (89%) made the journey to hospital under their own steam and would have had to travel a 4 times greater distance if the consultation with the specialist had taken place at the university hospital. Overall, 54.6% of patients were willing to travel 20 km further to see a specialist and 76.5% were willing to travel 20 km further for a surgical intervention. Virtually all of the patients (>99%) saw benefits to local consultations given by specialists. The offer of a consultation at the general hospital and intervention at the university hospital met with the approval of 60.8% patients and 56.3% had already experimented this offer. CONCLUSION: Local consultations by specialists might be an answer to demographic issues in France, that is, to the small number of urologists practicing in general hospitals.

Rotational resonance of nonaxisymmetric magnetic braking in the KSTAR tokamak.

One of the important rotational resonances in nonaxisymmetric neoclassical transport has been experimentally validated in the KSTAR tokamak by applying highly nonresonant n=1 magnetic perturbations to rapidly rotating plasmas. These so-called bounce-harmonic resonances are expected to occur in the presence of magnetic braking perturbations when the toroidal rotation is fast enough to resonate with periodic parallel motions of trapped particles. The predicted and observed resonant peak along with the toroidal rotation implies that the toroidal rotation in tokamaks can be controlled naturally in favorable conditions to stability, using nonaxisymmetric magnetic perturbations.

Evoked pressure curves from the external anal sphincter following transcranial magnetic stimulation in healthy volunteers and patients with faecal incontinence.

AIM: The hypothesis was tested that evoked pressure curves (EPCs) after transcranial magnetic stimulation (TMS) would provide additional neuropathophysiological information on the descending pathways to the external anal sphincter (EAS) in patients with faecal incontinence (FI). METHOD: Twenty-five healthy subjects and 69 patients with FI were investigated. TMS was applied to the vertex, and EPCs were recorded with a probe placed through the EAS. TMS was performed with the EAS at rest and during contraction (facilitated responses). At least three responses were recorded for each modality. Clinical data and anorectal manometric, electrophysiological perineal and transanal ultrasound recordings were compared with respect to the EPC results. RESULTS: There was no statistically significant difference between the EPCs of healthy subjects and FI patients. Twenty-three per cent of the FI patients had abnormal EPC latencies, with significantly lower voluntary contraction amplitudes (P = 0.03) and significantly higher rectal sensation (P = 0.04) than the other group. We found no significant difference between FI patients with and without abnormal EPC latencies in terms of clinical characteristics and electrophysiological and endoanal ultrasound parameters. There was no difference in the identified causes of the FI between the two groups. CONCLUSION: As abnormal EPC latencies were found in 23% of FI patients with no known central neurological disease, abnormal EPC latencies might reveal undetected lesions of descending pathways in patients with FI.

[Gynecological care among women reporting sexual violence: a qualitative study]. / Recours au soin gynécologique chez les femmes rapportant des violences sexuelles : étude qualitative.

INTRODUCTION: Sexual violence can be followed by different levels of gynecological care. Our objective was to characterise gynecological care and to identify the related factors among women who had reported sexual violence. METHODS: Twenty-five semi-structured interviews were conducted among adult women who reported sexual violence during childhood or as adults. Topics addressed included gynecological health, gynecological care and experienced violence, RESULTS: Interviewed women, aged 20-60, had a good professional integration and a high level of education. The violence had often been committed by a relative or acquaintance. For the women interviewed, the least use of gynecological care was motivated by a desire to avoid the gynecological examination. Among women who had regular check-ups, the desire to conform to the norm explained their need for gynecological check-ups, which was similar to that of women who had never been subjected to violence. Lastly, some care pathways were characterised by multiple recourse of gynecological care for complaints with identical motives. The women interviewed expected professionals to spontaneously identify the violence they had suffered and the gynecological consequences attributed to such violence. CONCLUSION: Individual and interpersonal differences in levels of gynecological care use were related to the characteristics of the violence and its perceived effects on gynecological health. It would be interesting to extend this research by examining the care pathways of women with other socioeconomic characteristics. A quantitative study would measure the association between violence and the use of gynecological care.

Transcutaneous electrical tibial nerve stimulation in the treatment of fecal incontinence: a randomized trial (CONSORT 1a).

OBJECTIVES: The objective of this study was to show that although transcutaneous electrical tibial nerve stimulation (TENS) is being increasingly used to treat fecal incontinence (FI), its efficacy has never been proved using controlled trials. METHODS: In this randomized, double-blind, sham-controlled trial, 144 patients aged 30-82 years from nine centers were randomly assigned to receive either active or sham stimulations for 3 months. The primary end point was the response to treatment based on the number of incontinence and urgency episodes. Secondary end points were severity scores, quality of life scores, delay to postpone defecation, patient self-assessment of treatment efficacy, physician assessment of TENS efficacy, anorectal manometry, and adverse events. RESULTS: No statistically significant difference was seen between active and sham TENS in terms of an improvement in the median number of FI/urgency episodes per week. Thirty-four patients (47%) who received the active TENS treatment exhibited a >30% decrease in the FI severity score compared with 19 patients (27%) who received the sham treatment (odds ratio 2.4, 95% confidence interval 1.1-5.1, P=0.02). No differences in delay to postpone defecation, patient self-assessment of treatment efficacy, or anorectal manometry were seen between the two groups. The evaluating physicians rated the active stimulations as more effective than the sham stimulations (P=0.01). One minor therapy-related adverse event was observed (1.5%) (see Supplementary Consort 1b). CONCLUSIONS: We failed to demonstrate any benefit of TENS on our primary end-point.

Relationship between conventional sperm parameters and motile sperm organelle morphology examination (MSOME).

With the motile sperm organelle morphology examination (MSOME), spermatozoa morphology may be assessed directly on motile spermatozoa at high magnification (up to 6600×). This procedure describes more precisely spermatozoa abnormalities, especially head vacuoles. However, no consensus has been established concerning normal or abnormal MSOME criteria. The aim of our study was to define MSOME vacuole criteria assessed objectively with a digital imaging system software to establish a potential relationship between conventional semen parameters. A total of 440 semen samples were obtained from males consulting in Rouen University Hospital Reproductive Biology Laboratory. Conventional semen analysis (volume, sperm concentration, progressive motility, vitality and morphology) and MSOME assessment {sperm head length, width and area as well as vacuole number, vacuole area and relative vacuole area to sperm head [RVA (%) = [vacuole area (µm(2))/head area (µm(2))] × 100)]} were performed for each semen sample. Among our 440 males, 109 presented normal conventional semen parameters and 331 abnormal ones. Sperm head vacuoles were significantly larger in abnormal semen samples (p < 0.0001). RVA was the most discriminative MSOME criterion between normal and abnormal semen samples according to ROC curves analysis, and was negatively correlated with poor sperm morphology (r = -0.53, p < 0.0001). We concluded to (i) the normal occurrence of vacuoles in sperm head whatever the normality or abnormality of semen parameters, (ii) the discriminative function of the RVA to distinguish semen samples with normal and abnormal parameters, and (iii) the strong correlation between high RVA and poor sperm morphology.

Self-collected vaginal swabs for the quantitative real-time polymerase chain reaction assay of Atopobium vaginae and Gardnerella vaginalis and the diagnosis of bacterial vaginosis.

The aim of this study was to assess the feasibility of using self-collected vaginal specimens for the quantitative real-time polymerase chain reaction (qPCR) assays of bacterial vaginosis (BV)-associated bacteria versus practitioner-collected swabs. A cross-sectional study included 190 pregnant women enrolled before 20 weeks' gestation from September 2008 to November 2009. Self- and practitioner-collected swabs were taken during the same prenatal visit for each woman, qPCR assays performed for each, and the results compared. The quantification of the human albumin gene was used as an internal control to ensure sampling quality and accurate comparisons. The level of agreement of the qPCR assays for each microorganism was calculated with the Spearman product moment correlation coefficient and the kappa statistic. In all, 370 vaginal samples (185 self- and 185 practitioner-collected swabs) had a narrow range of values for the number of albumin gene copies and a significant correlation coefficient (Spearman's rho = 0.532; p < 0.001). The agreement between both sampling methods was excellent (Spearman's rho was 0.748 for Atopobium vaginae, 0.918 for Lactobacillus species, 0.940 for Gardnerella vaginalis; p < 0.001), especially for high concentrations of A. vaginae (≥10(8) copies/mL; kappa value = 0.973; p < 0.001) and G. vaginalis (≥10(9) copies/mL; kappa value = 0.903; p < 0.001). This study demonstrates the validity and reliability of self- versus practitioner-collected swabs for the molecular quantification of Lactobacillus species, G. vaginalis, and A. vaginae.

Short-term and long-term outcomes of interstitial lung disease in polymyositis and dermatomyositis: a series of 107 patients.

OBJECTIVE: This study was undertaken to assess the characteristics and outcome of interstitial lung disease (ILD) in polymyositis/dermatomyositis (PM/DM) and to determine variables predictive of ILD deterioration in PM/DM. METHODS: Among 348 consecutive patients with PM/DM, 107 patients with ILD were identified by medical records search in 4 medical centers. All patients underwent pulmonary function tests (PFTs) and pulmonary high-resolution computed tomography (HRCT) scan. RESULTS: ILD onset preceded PM/DM clinical manifestations in 20 patients, was identified concurrently with PM/DM in 69 patients, and occurred after PM/DM onset in 18 patients. Patients with ILD could be divided into 3 groups according to their presenting lung manifestations: patients with acute lung disease (n = 20), patients with progressive-course lung signs (n = 55), and asymptomatic patients with abnormalities consistent with ILD evident on PFTs and HRCT scan (n = 32). We observed that 32.7% of the patients had resolution of pulmonary disorders, whereas 15.9% experienced ILD deterioration. Factors that predicted a poor ILD prognosis were older age, symptomatic ILD, lower values of vital capacity and diffusing capacity for carbon monoxide, a pattern of usual interstitial pneumonia on HRCT scan and lung biopsy, and steroid-refractory ILD. The mortality rate was higher in patients with ILD deterioration than in those without ILD deterioration (47.1% versus 3.3%). CONCLUSION: Our findings indicate that ILD results in high morbidity in PM/DM. Our findings also suggest that more aggressive therapy may be required in PM/DM patients presenting with factors predictive of poor ILD outcome.

[Endothelin-1 and receptor A: predictive value for biochemical relapse on patients with advanced and metastatic prostate cancer]. / Endothéline-1 et récepteur A: valeur pronostique pour la reprise évolutive biologique dans l'adénocarcinome de prostate localement avancé et métastatique ganglionnaire.

INTRODUCTION: Pathological endothelin axis is known to be involved in prostate cancer progression. Our study evaluates immunohistochemical expression of ET-1 and ET-AR on prostate biopsy specimen and the predictive value for biochemical relapse on patients with advanced and metastatic cancer. We also evaluated the impact of ET-1 and ET-AR expression on local progression and metastatic bone progression for these patients. PATIENTS AND METHOD: From 1992 to June 2009, 44 patients with clinical T3 stage and metastatic lymph nodes were included. PSA levels, Gleason score in biopsy cores, number of invaded lymph nodes, the existence of nodular capsule transgression and hormonal treatment given to the patient, were analyzed. Biopsy cores were submitted to immunohistochemical study of the expression of ET-1 and ET-AR. Semi-quantitative ET-1 and ET-AR staining assessment was always realised by the same pathologist. RESULTS: The average age of the cohort was 65.6 (standard deviation 6.3), median PSA level was 52.8 ng /ml (3-227), median time of follow-up was 70 months (6-144). Biochemical relapse was observed in 62.8%. Statistically significant stronger ET-1 expression was observed in biopsies of patients with a biochemical relapse (p=0.014). Eighty percent of patients with a biochemical relapse had a high level of ET-AR expression, but no statistical significance has been shown (p=0.109). The relative risk for progression under hormonal therapy was 1.9 in case of high level of ET-1 expression and biochemical relapse was confirmed 8 months earlier in average. High level of ET-AR expression on biopsy cores may indicate earlier local progression and metastatic bone progression but there were no statistical proof. CONCLUSION: In our study, the strength of ET-1 expression in prostate cancer biopsy cores is a prognostic factor of biochemical relapse for cT3 stage patients with metastatic lymph nodes. We have not been able to prove that ET-1 is an independent prognostic factor. A high level of ET-AR expression on prostate biopsy cores is not, in our study, a prognosis factor for predicting the biochemical relapse.

AC compensation of 3D magnetic diagnostic signals in DIII-D and National Spherical Torus Experiment-Upgrade (NSTX-U) for real-time application.

A time domain algorithm has been developed to remove the vacuum pickup generated by both coil current (DC) and induced vessel current (AC) in real time from three dimensional (3D) magnetic diagnostic signals in the National Spherical Torus Experiment-Upgrade (NSTX-U) and DIII-D tokamaks. The possibility of detecting 3D plasma perturbations in real time is essential in modern and future tokamaks to avoid and control MHD instabilities. The presence of vacuum field pickup, due to toroidally asymmetric (3D) coils or to misalignment between sensors and axisymmetric (2D) coils, pollutes the measured plasma 3D field, making the detection of the magnetic field produced by the plasma challenging. Although the DC coupling between coils and sensors can be easily calculated and removed, the AC part is more difficult. An algorithm based on a layered low-pass filter approach for the AC compensation and its application for DIII-D and NSTX-U data is presented, showing that this method reduces the vacuum pickup to the noise level. Comparison of plasma response measurements with and without vacuum compensation shows that accurate mode locking detection and plasma response identification require precise AC and DC compensations.

Measuring perfusion and bioenergetics simultaneously in mouse skeletal muscle: a multiparametric functional-NMR approach.

A totally noninvasive set-up was developed for comprehensive NMR evaluation of mouse skeletal muscle function in vivo. Dynamic pulsed arterial spin labeling-NMRI perfusion and blood oxygenation level-dependent (BOLD) signal measurements were interleaved with (31)P NMRS to measure both vascular response and oxidative capacities during stimulated exercise and subsequent recovery. Force output was recorded with a dedicated ergometer. Twelve exercise bouts were performed. The perfusion, BOLD signal, pH and force-time integral were obtained from mouse legs for each exercise. All reached a steady state after the second exercise, justifying the pointwise summation of the last 10 exercises to compensate for the limited (31)P signal. In this way, a high temporal resolution of 2.5 s was achieved to provide a time constant for phosphocreatine (PCr) recovery (τ(PCr)). The higher signal-to-noise ratio improved the precision of τ(PCr) measurement [coefficient of variation (CV) = 16.5% vs CV = 49.2% for a single exercise at a resolution of 30 s]. Inter-animal summation confirmed that τ(PCr) was stable at steady state, but shorter (89.3 ± 8.6 s) than after the first exercise (148 s, p < 0.05). This novel experimental approach provides an assessment of muscle vascular response simultaneously to energetic function in vivo. Its pertinence was illustrated by observing the establishment of a metabolic steady state. This comprehensive tool offers new perspectives for the study of muscle pathology in mice models.

Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: results of trial stimulation in 200 patients.

AIM: Sacral nerve stimulation (SNS) has a place in the treatment algorithm for faecal incontinence (FI). However, after implantation, 15-30% of patients with FI fail to respond for unknown reasons. We investigated the effect of SNS on continence and quality of life (QOL) and tried to identify specific predictive factors of the success of permanent SNS in the treatment of FI. METHOD: Two hundred consecutive patients (six men; median age = 60; range 16-81) underwent permanent implantation for FI. The severity of FI was evaluated by the Cleveland Clinic Score. Quality of life was evaluated by the French version of the American Society of Colon and Rectal Surgeons (ASCRS) quality of life questionnaire (FIQL). All patients underwent a preoperative evaluation. After permanent implantation, severity and QOL scores were reevaluated after six and 12 months and then once a year. RESULTS: The severity scores were significantly reduced during SNS (P = 0.001). QOL improved in all domains. At the 6-month follow-up, the clinical outcome of the permanent implant was not affected by age, gender, duration of symptoms, QOL, main causes of FI, anorectal manometry or endoanal ultrasound results. Only loose stool consistency (P = 0.01), persistent FI even though diarrhoea was controlled by medical treatment (P = 0.004), and low stimulation intensity (P = 0.02) were associated with improved short-term outcomes. Multivariate analysis confirmed that loose stool consistency and low stimulation intensity were related to a favourable outcome. CONCLUSION: Stool consistency and low stimulation intensity have been identified as predictive factors for the short-term outcome of SNS.