Mapping the current flow in sacral nerve stimulation using computational modelling

© The Institution of Engineering and Technology 2019Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence involving the implantation of a quadripolar electrode into a sacral foramen, through which an electrical stimulus is applied. Little is known about the induced spread of electric current around the SNS electrode and its effect on adjacent tissues, which limits optimisation of this treatment. The authors constructed a 3-dimensional imaging based finite element model in order to calculate and visualise the stimulation induced current and coupled this to biophysical models of nerve fibres. They investigated the impact of tissue inhomogeneity, electrode model choice and contact configuration and found a number of effects. (i) The presence of anatomical detail changes the estimate of stimulation effects in size and shape. (ii) The difference between the two models of electrodes is minimal for electrode contacts of the same length. (iii) Surprisingly, in this arrangement of electrode and neural fibre, monopolar and bipolar stimulation induce a similar effect. (iv) Interestingly when the active contact is larger, the volume of tissue activated reduces. This work establishes a protocol to better understand both therapeutic and adverse stimulation effects and in the future will enable patient-specific adjustments of stimulation parameters.Peer reviewe

Data gathering, surveillance and human rights: recasting the debate

The nature and depth of internet surveillance has been revealed to be very different from what had previously been publically acknowledged or politically debated. There are critical ways in which the current debate is miscast, misleading and confused. Privacy is portrayed as an individual right, in opposition to a collective need for security. Data gathering and surveillance are portrayed as having an impact only on this individual right to privacy, rather than on a broad spectrum of rights, including freedom of expression, of assembly and association, the prohibition of discrimination and more. The gathering and surveillance of ‘content’ is intrinsically more intrusive than that of ‘communications’ data or ‘metadata’. The impact of data gathering and surveillance is often portrayed as happening only at when data are examined by humans rather than when gathered, or when examined algorithmically. Commercial and governmental data gathering and surveillance are treated as separate and different, rather than intrinsically and inextricably linked. This miscasting has critical implications. When the debate is recast taking into account these misunderstandings, the bar for the justification of surveillance is raised and a new balance needs to be found, in political debate, in law, and in decision-making on the ground

Comfort radicalism and NEETs: a conservative praxis

Young people who are not in education, employment or training (NEET) are construed by policy makers as a pressing problem about which something should be done. Such young people's lack of employment is thought to pose difficulties for wider society in relation to social cohesion and inclusion and it is feared that they will become a 'lost generation'. This paper(1) draws upon English research, seeking to historicise the debate whilst acknowledging that these issues have a much wider purchase. The notion of NEETs rests alongside longstanding concerns of the English state and middle classes, addressing unruly male working class youth as well as the moral turpitude of working class girls. Waged labour and domesticity are seen as a means to integrate such groups into society thereby generating social cohesion. The paper places the debate within it socio-economic context and draws on theorisations of cognitive capitalism, Italian workerism, as well as emerging theories of antiwork to analyse these. It concludes by arguing that ‘radical’ approaches to NEETs that point towards inequities embedded in the social structure and call for social democratic solutions veer towards a form of comfort radicalism. Such approaches leave in place the dominance of capitalist relations as well as productivist orientations that celebrate waged labour

Overdiagnosis and rising rate of obstetric anal sphincter injuries (OASIS): time for reappraisal

OBJECTIVES: To identify the accuracy of clinically diagnosed OASIS using 3D endoanal ultrasound and compare symptoms and anal manometry measurements between those whose anal sphincters were adequately repaired to those who had persistent anal sphincter defects. METHODS: The endoanal scan images of women who sustained OASIS and attended the perineal clinic over a 10 year period (2003 - 2013) were re-analysed from data entered prospectively of women with clinically diagnosed and repaired OASIS. The St Mark's Incontinence Score (SMIS) as well as anal manometry measurements were included in the analysis. RESULTS: The images of 908 women were re-analysed. We found that there was no evidence of OASIS (Group A) = 64 (7%); external anal sphincter (EAS) scar alone (Group B) = 520 (57.3%); anal sphincter defect (Group C) = 324 (35.7%). Of the 324 women with a defect, 112 had an EAS defect and 90 had an internal anal sphincter (IAS) defect and 122 had a combined IAS + EAS defect. The SMIS was significantly higher in women with a defect (p = 0.018) but there was no significant difference in scores between women with an intact sphincter and women with a scar. Compared to the intact group, both the maximum resting (median and range [55 (29-86) vs 43.5 (8-106) mmHg; p < 0.001] and maximum squeeze pressures [103 (44-185) vs 73.5, (23-180); p < 0.001] were significantly lower in women with a defect but less so with a scar. The anal length was significantly shorter in woman with a defect [25 (10-40) vs 20 (10-40) mm]. CONCLUSIONS: Seven percent of women who had a clinical diagnosis of OASIS were wrongly diagnosed as they only had a second degree tear. We believe that this rate may differ from other units but training methods and competency assessment tools for the diagnosis and repair of OASIS need urgent reappraisal. The role of anal ultrasound in the immediate post-partum period needs further evaluation as it will be dependent on the expertise of the staff available to accurately interpret the images

The HubBLe Trial: haemorrhoidal artery ligation (HAL) versus rubber band ligation (RBL) for symptomatic second- and third-degree haemorrhoids: a multicentre randomised controlled trial and health-economic evaluation.

BACKGROUND: Optimal surgical intervention for low-grade haemorrhoids is unknown. Rubber band ligation (RBL) is probably the most common intervention. Haemorrhoidal artery ligation (HAL) is a novel alternative that may be more efficacious. OBJECTIVE: The comparison of HAL with RBL for the treatment of grade II/III haemorrhoids. DESIGN: A multicentre, parallel-group randomised controlled trial. PERSPECTIVE: UK NHS and Personal Social Services. SETTING: 17 NHS Trusts. PARTICIPANTS: Patients aged ≥ 18 years presenting with grade II/III (second- and third-degree) haemorrhoids, including those who have undergone previous RBL. INTERVENTIONS: HAL with Doppler probe compared with RBL. OUTCOMES: Primary outcome - recurrence at 1 year post procedure; secondary outcomes - recurrence at 6 weeks; haemorrhoid severity score; European Quality of Life-5 Dimensions, 5-level version (EQ-5D-5L); Vaizey incontinence score; pain assessment; complications; and cost-effectiveness. RESULTS: A total of 370 participants entered the trial. At 1 year post procedure, 30% of the HAL group had evidence of recurrence compared with 49% after RBL [adjusted odds ratio (OR) = 2.23, 95% confidence interval (CI) 1.42 to 3.51; p = 0.0005]. The main reason for the difference was the number of extra procedures required to achieve improvement/cure. If a single HAL is compared with multiple RBLs then only 37.5% recurred in the RBL arm (adjusted OR 1.35, 95% CI 0.85 to 2.15; p = 0.20). Persistence of significant symptoms at 6 weeks was lower in both arms than at 1 year (9% HAL and 29% RBL), suggesting significant deterioration in both groups over the year. Symptom score, EQ-5D-5L and Vaizey score improved in both groups compared with baseline, but there was no difference between interventions. Pain was less severe and of shorter duration in the RBL group; most of the HAL group who had pain had mild to moderate pain, resolving by 3 weeks. Complications were low frequency and not significantly different between groups. It appeared that HAL was not cost-effective compared with RBL. In the base-case analysis, the difference in mean total costs was £1027 higher for HAL. Quality-adjusted life-years (QALYs) were higher for HAL; however, the difference was very small (0.01) resulting in an incremental cost-effectiveness ratio of £104,427 per additional QALY. CONCLUSIONS: At 1 year, although HAL resulted in fewer recurrences, recurrence was similar to repeat RBL. Symptom scores, complications, EQ-5D-5L and continence score were no different, and patients had more pain in the early postoperative period after HAL. HAL is more expensive and unlikely to be cost-effective in terms of incremental cost per QALY. LIMITATIONS: Blinding of participants and site staff was not possible. FUTURE WORK: The incidence of recurrence may continue to increase with time. Further follow-up would add to the evidence regarding long-term clinical effectiveness and cost-effectiveness. The polysymptomatic nature of haemorrhoidal disease requires a validated scoring system, and the data from this trial will allow further assessment of validity of such a system. These data add to the literature regarding treatment of grade II/III haemorrhoids. The results dovetail with results from the eTHoS study [Watson AJM, Hudson J, Wood J, Kilonzo M, Brown SR, McDonald A, et al. Comparison of stapled haemorrhoidopexy with traditional excisional surgery for haemorrhoidal disease (eTHoS): a pragmatic, multicentre, randomised controlled trial. Lancet 2016, in press.] comparing stapled haemorrhoidectomy with excisional haemorrhoidectomy. Combined results will allow expansion of analysis, allowing surgeons to tailor their treatment options to individual patients. TRIAL REGISTRATION: Current Controlled Trials ISRCTN41394716. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 88. See the NIHR Journals Library website for further project information

Stepped-wedge randomised trial of laparoscopic ventral mesh rectopexy in adults with chronic constipation: Study protocol for a randomized controlled trial

BACKGROUND: Laparoscopic ventral mesh rectopexy (LVMR) is an established treatment for external full-thickness rectal prolapse. However, its clinical efficacy in patients with internal prolapse is uncertain due to the lack of high-quality evidence. METHODS: An individual level, stepped-wedge randomised trial has been designed to allow observer-blinded data comparisons between patients awaiting LVMR with those who have undergone surgery. Adults with symptomatic internal rectal prolapse, unresponsive to prior conservative management, will be eligible to participate. They will be randomised to three arms with different delays before surgery (0, 12 and 24 weeks). Efficacy outcome data will be collected at equally stepped time points (12, 24, 36 and 48 weeks). The primary objective is to determine clinical efficacy of LVMR compared to controls with reduction in the Patient Assessment of Constipation Quality of Life (PAC-QOL) at 24 weeks serving as the primary outcome. Secondary objectives are to determine: (1) the clinical effectiveness of LVMR to 48 weeks to a maximum of 72 weeks; (2) pre-operative determinants of outcome; (3) relevant health economics for LVMR; (4) qualitative evaluation of patient and health professional experience of LVMR and (5) 30-day morbidity and mortality rates. DISCUSSION: An individual-level, stepped-wedge, randomised trial serves the purpose of providing an untreated comparison for the active treatment group, while at the same time allowing the waiting-listed participants an opportunity to obtain the intervention at a later date. In keeping with the basic ethical tenets of this design, the average waiting time for LVMR (12 weeks) will be shorter than that for routine services (24 weeks)

Major Complex Abdominal Wall Repair in Contaminated Fields with Use of a Non-cross-linked Biologic Mesh: A Dual-Institutional Experience

Background Data on the use of biologic mesh in abdominal wall repair in complex cases remain sparse. Aim of this study was to evaluate a non-cross-linked porcine acellular dermal matrix for repair of complex contaminated abdominal wall defects. Methods Retrospective observational cohort study of consecutive patients undergoing abdominal wall repair with use of Strattice™ Reconstructive Tissue Matrix (LifeCell Corporation, Oxford, UK) between January 2011 and February 2015 at two National Intestinal Failure Units. Results Eighty patients were identified. Indications for abdominal wall repair included enterocutaneous fistula takedown (n = 50), infected synthetic mesh removal (n = 9), restoration of continuity or creation of a stoma with concomitant ventral hernia repair (n = 12), and others (n = 9). The median defect area was 143.0 cm2 (interquartile range or IQR 70.0–256.0 cm2). All had a grade III or IV hernia. Component separation technique (CST) was performed in 54 patients (68%). Complete fascial closure was not possible despite CST and biologic mesh-assisted traction (bridged repair) in 20 patients (25%). In-hospital mortality was 1%. Thirty-six patients (45%) developed a wound infection. None required mesh removal. Of 76 patients with a median clinical follow-up of 7 months (IQR 4–15) available for analysis, 10 patients (13%) developed a hernia recurrence, of whom 3 had undergone bridged repairs. Seven patients developed a postoperative (recurrent) fistula (9%). Conclusion Repair of challenging and contaminated abdominal wall defects can be done effectively with non-cross-linked biologic mesh and component separation technique without the need for mesh removal despite wound infections