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

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

Prospective study of immunological factors in non-inflammatory bowel disease enterocutaneous fistulas

© 2011 The Authors. Published by BMC, part of Springer Nature. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1186/1471-2482-11-12Background: Enterocutaneous fistulas (ECF) are debilitating and usually result following complex abdominal surgery. While there is an association with inflammatory bowel disease (IBD), a large number of fistulas occur after surgery not related to IBD. The consequences of ECF include short bowel syndrome and the need for long term parenteral nutrition. ECF can heal spontaneously and in the case of IBD can be cured by medical therapy in some instances. Those that do not resolve spontaneously have to be cured by surgery which is complex and associated with a high morbidity. It is not considered traditional treatment to use the same medical therapy as in IBD to cure ECF caused by other conditions. A small case series has reported three patients with persistent ECF not related to IBD to have healed following use of Infliximab which is the treatment commonly used for ECF caused by IBD. Infliximab acts by inhibiting the activity of the inflammatory cytokine TNF- alpha. It is not known if this cytokine is present in ECF tissue in the absence of IBD. The aim of this study is to demonstrate the presence of inflammatory markers in tissue surrounding non-IBD ECF and in particular to quantify the presence of the cytokine TNF- alpha. We hypothesise that TNF - alpha levels are raised in non-IBD ECF. Methods/Design. Tissue and serum from ECF of IBD and non-IBD patients will be prospectively collected at St. Mark's Hospital Intestinal Failure Unit. The control group will consist of patients undergoing colonoscopy for bowel cancer screening, with normal findings. Biopsies of the terminal ileum will be obtained from this group during colonoscopy. The fistula tract and serum cytokine profiles of interleukins (IL)-1a, IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, TNF- alpha, IFN-y, MCP-1, EGF and VEGF will be assessed. Discussion. This study aims to assess the presence or absence of TNF- alpha expression in the ECF tissue in non-IBD origin. If our hypothesis is correct we would then be able to study the use of the TNF- alpha inhibitor Infliximab as a therapeutic option in the treatment of non-IBD ECF. Secondary aims include assessing the spectrum of inflammatory cytokines and markers present in tissue and serum of non-IBD ECF when compared with IBD ECF and normal controls. © 2011 Rahbour et al; licensee BioMed Central Ltd.The study has secured funding from Bowel Disease Research Foundation (BDRF).Published versio

Double-blind randomised controlled trial of percutaneous tibial nerve stimulation versus sham electrical stimulation in the treatment of faecal incontinence: CONtrol of Faecal Incontinence using Distal NeuromodulaTion (the CONFIDeNT trial)

Background: Faecal incontinence (FI) is a common condition which is often under-reported. It is distressing for those suffering from it, impacting heavily on their quality of life. When conservative strategies fail, treatment options are limited. Percutaneous tibial nerve stimulation (PTNS) is a minimally invasive outpatient treatment, shown in preliminary case series to have significant effectiveness; however, no randomised controlled trial has been conducted. Objectives: To assess the effectiveness of PTNS compared with sham electrical stimulation in the treatment of patients with FI in whom initial conservative strategies have failed. Design: Multicentre, parallel-arm, double-blind randomised (1 : 1) controlled trial. Setting: Eighteen UK centres providing specialist nurse-led (or equivalent) treatment for pelvic floor disorders. Participants: Participants aged > 18 years with FI who have failed conservative treatments and whose symptoms are sufficiently severe to merit further intervention. Interventions: PTNS was delivered via the Urgent® PC device (Uroplasty Limited, Manchester, UK), a hand-held pulse generator unit, with single-use leads and fine-needle electrodes. The needle was inserted near the tibial nerve on the right leg adhering to the manufacturer’s protocol (and specialist training). Treatment was for 30 minutes weekly for a duration of 12 treatments. Validated sham stimulation involved insertion of the Urgent PC needle subcutaneously at the same site with electrical stimulation delivered to the distal foot using transcutaneous electrical nerve stimulation. Main outcome measures: Outcome measures were assessed at baseline and 2 weeks following treatment. Clinical outcomes were derived from bowel diaries and validated, investigator-administered questionnaires. The primary outcome classified patients as responders or non-responders, with a responder defined as someone having achieved ≥ 50% reduction in weekly faecal incontinence episodes (FIEs). Results: In total, 227 patients were randomised from 373 screened: 115 received PTNS and 112 received sham stimulation. There were 12 trial withdrawals: seven from the PTNS arm and five from the sham arm. Missing data were multiply imputed. For the primary outcome, the proportion of patients achieving a ≥ 50% reduction in weekly FIEs was similar in both arms: 39 in the PTNS arm (38%) compared with 32 in the sham arm (31%) [odds ratio 1.28, 95% confidence interval (CI) 0.72 to 2.28; p = 0.396]. For the secondary outcomes, significantly greater decreases in weekly FIEs were observed in the PTNS arm than in the sham arm (beta –2.3, 95% CI –4.2 to –0.3; p = 0.02), comprising a reduction in urge FIEs (p = 0.02) rather than passive FIEs (p = 0.23). No significant differences were found in the St Mark’s Continence Score or any quality-of-life measures. No serious adverse events related to treatment were reported. Conclusions: PTNS did not show significant clinical benefit over sham electrical stimulation in the treatment of FI based on number of patients who received at least a 50% reduction in weekly FIE. It would be difficult to recommend this therapy for the patient population studied. Further research will concentrate on particular subgroups of patients, for example those with pure urge FI. Trial registration: Current Controlled Trials ISRCTN88559475. Funding: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 77. See the NIHR Journals Library website for further project information

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

The development of a faecal incontinence core outcome set: an international Delphi study protocol

Purpose Faecal incontinence (FI) is estimated to affect around 7.7% of people. There is a lack of uniformity in outcome definitions, measurement and reporting in FI studies. Until now, there is no general consensus on which outcomes should be assessed and reported in FI research. This complicates comparison between studies and evidence synthesis, potentially leading to recommendations not evidence-based enough to guide physicians in selecting an FI therapy. A solution for this lack of uniformity in reporting of outcomes is the development of a Core Outcome Set (COS) for FI. This paper describes the protocol for the development of a European COS for FI. Methods Patient interviews and a systematic review of the literature will be performed to identify patient-, physician- and researcher-oriented outcomes. The outcomes will be categorised using the COMET taxonomy and put forward to a group of patients, physicians (i.e. colorectal surgeons, gastroenterologists and general practitioners) and researchers in a Delphi consensus exercise. This exercise will consist of up to three web-based rounds in which participants will prioritise and condense the list of outcomes, which is expected to result in consensus. A consensus meeting with participants from all stakeholder groups will take place to reach a final agreement on the COS. Discussion This study protocol describes the development of a European COS to improve reliability and consistency of outcome reporting in FI studies, thereby improving evidence synthesis and patient care

Transanal minimal invasive surgery for rectal lesions: should the defect be closed?

AIM: Transanal minimal invasive surgery (TAMIS) of rectal lesions is increasingly being used, but the technique is not yet standardized. The aims of this study were to evaluate peri-operative complications and long-term functional outcome of the technique and to analyse whether or not the rectal defect needs to be closed. METHOD: Consecutive patients undergoing TAMIS using the SILS port (Covidien) and standard laparoscopic instruments were studied. RESULTS: Seventy-five patients (68% male) of mean age 67 (± 15) years underwent single-port transanal surgery at three different centres for 37 benign lesions and 38 low-risk cancers located at a mean of 6.4 ± 2.3 cm from the anal verge. The median operating time was 77 (25-245) min including a median time for resection of 36 (15-75) min and for closure of the rectal defect of 38 (9-105) min. The defect was closed in 53% using interrupted (75%) or a running suture (25%). Intra-operative complications occurred in six (8%) patients and postoperative morbidity was 19% with only one patient requiring reoperation for Grade IIIb local infection. There was no difference in the incidence of complications whether the rectal defect was closed or left open. Patients were discharged after 3.4 (1-21) days. At a median follow-up of 12.8 (2-29) months, the continence was normal (Vaizey score of 1.5; 0-16). CONCLUSION: Transanal rectal resection can be safely and efficiently performed by means of a SILS port and standard laparoscopic instruments. The rectal defect may be left open and at 1 year continence is not compromised