Haemorrhoids

Clinical information monographHaemorrhoids are vascular-rich connective tissue cushions located within the anal canal. Internal haemorrhoids lie proximal to the dentate line in the anal canal, whereas external haemorrhoids are located distal to the dentate line. Haemorrhoidal disease presents as painless rectal bleeding or sudden onset of perianal pain with a tender palpable perianal mass. Diagnosis is confirmed with visualisation of the protruding tissue or anoscopic visualisation. Treatment includes increasing dietary fibre, rubber band ligation, infrared photocoagulation, sclerotherapy, or surgical haemorrhoidectomy. Complications include recurrence or worsening of symptoms, excessive bleeding, non-reducible prolapse, and, rarely, pelvic sepsis

Diverticular disease

PhD monograp

Cost-effectiveness of sacral nerve stimulation and percutaneous tibial nerve stimulation for faecal incontinence

Background: Subcutaneous sacral nerve stimulation is recommended by NICE as a second line treatment for patients with faecal incontinence who failed conservative therapy. Sacral nerve stimulation is an invasive procedure associated with complications and reoperations. This study aimed to investigate whether delivering less invasive and less costly percutaneous tibial nerve stimulation prior to sacral nerve stimulation is cost-effective. Methods: A decision analytic model was developed to estimate the cost-effectiveness of percutaneous tibial nerve stimulation with subsequent subcutaneous sacral nerve stimulation versus subcutaneous sacral nerve stimulation alone. The model was populated with effectiveness data from systematic reviews and cost data from randomized studies comparing both procedures in an NHS setting. Results: Offering percutaneous tibial nerve stimulation prior to sacral nerve stimulation (compared to delivering sacral nerve stimulation straight away) was both more effective and less costly in all modeled scenarios. The estimated savings from offering percutaneous tibial nerve stimulation first were £662 - £5,697 per patient. The probability of this strategy being cost-effective was around 80% at £20,000 -£30,000 per QALY. Conclusion: Our analyses suggest that offering patients percutaneous tibial nerve stimulation prior to sacral nerve stimulation can be both cost effective and cost saving in the treatment of faecal incontinence

In silico and in vivo investigations using an endocavitary photoplethysmography sensor for tissue viability monitoring

Significance: Colorectal cancer is one of the major causes of cancer-related deaths worldwide. Surgical removal of the cancerous growth is the primary treatment for this disease. A colorectal cancer surgery, however, is often unsuccessful due to the anastomotic failure that may occur following the surgical incision. Prevention of an anastomotic failure requires continuous monitoring of intestinal tissue viability during and after colorectal surgery. To date, no clinical technology exists for the dynamic and continuous monitoring of the intestinal perfusion. Aim: A dual-wavelength indwelling bowel photoplethysmography (PPG) sensor for the continuous monitoring of intestinal viability was proposed and characterized through a set of in silico and in vivo investigations. Approach: The in silico investigation was based on a Monte Carlo model that was executed to quantify the variables such as penetration depth and detected intensity with respect to the sensor–tissue separations and tissue perfusion. Utilizing the simulated information, an indwelling reflectance PPG sensor was designed and tested on 20 healthy volunteers. Two sets of in vivo studies were performed using the driving current intensities 20 and 40 mA for a comparative analysis, using buccal tissue as a proxy tissue-site. Results: Both simulated and experimental results showed the efficacy of the sensor to acquire good signals through the “contact” to a “noncontact” separation of 5 mm. A very slow wavelength-dependent variation was shown in the detected intensity at the normal and hypoxic states of the tissue, whereas a decay in the intensity was found with the increasing submucosal-blood volume. The simulated detected-to-incident-photon-ratio and the experimental signal-to-noise ratio exhibited strong positive correlations, with the Pearson product-moment correlation coefficient R ranging between 0.65 and 0.87. Conclusions: The detailed feasibility analysis presented will lead to clinical trials utilizing the proposed sensor

A review of modeling and control of remote-controlled capsule endoscopes.

INTRODUCTION: The significance of this review lies in addressing the limitations of passive locomotion in capsule endoscopes, hindering their widespread use in medical applications. The research focuses on evaluating existing miniature in vivo remote-controlled capsule endoscopes, examining their locomotion designs, and working theories to pave the way for overcoming challenges and enhancing their applicability in diagnostic and treatment settings. AREAS COVERED: This paper explores control methods and dynamic system modeling in the context of self-propelled remote-controlled capsule endoscopes with a two-mass arrangement. The literature search, conducted at Queen Mary University of London Library from 2000 to 2022, utilized a systematic approach starting with the broad keyword 'Capsule Endoscope' and progressively narrowing down to specific aspects such as 'Capsule Endoscope Control' and 'Self-propelled Capsule Endoscope' using various criteria. EXPERT OPINION: Efficiently driving and controlling remote-controlled capsule endoscopes have the potential to overcome the current limitations in medical technology, offering a viable solution for diagnosing and treating gastrointestinal diseases. Successful control of the remote-controlled capsule endoscope, as demonstrated in this review paper, will lead to a step change in medical engineering, establishing the remote-controlled capsule endoscope as a swift standard in the field

Anterior Perineal PlanE for ultra-low Anterior Resection of the rectum (APPEAR) technique: A systematic review

Rectal surgery, Perineal incision, Rectal cancer, Inflammatory bowel disease, Rectal strictureRectal surgery, Perineal incision, Rectal cancer, Inflammatory bowel disease, Rectal strictureKathryn Lynes is funded by The David Johnston Fellowship from The Royal College of Surgeons of England

Proof-of-principle validation of a novel intraluminal optical sensor for dynamic monitoring of intestinal anastomosis: An in vivo animal model case study

Intestinal resections are commonly performed to treat different colorectal conditions, including colorectal cancer. A successful primary anastomosis is the desired optimal outcome after intestinal resection. Maintaining adequate blood flow across the anastomosis is paramount for reducing anastomotic failure. Currently, there are no clinical devices capable of continuously assessing blood flow and blood perfusion at an anastomosis during and after surgery. The aim of this study was to develop an indwelling optical sensor for the monitoring of perfusion biomarkers using photoplethysmography and near-infrared spectroscopy principles. In an animal in-vivo proof-of-principle study, it was found that the developed sensor performed appropriately for the assessment of blood flow and perfusion in an anastomosis, showing changes in the assessed parameters after gradual devascularization of the transected bowel

P2Y Receptors Sensitize Mouse and Human Colonic Nociceptors

Activation of visceral nociceptors by inflammatory mediators contributes to visceral hypersensitivity and abdominal pain associated with many gastrointestinal disorders. Purine and pyrimidine nucleotides (e.g., ATP and UTP) are strongly implicated in this process following their release from epithelial cells during mechanical stimulation of the gut, and from immune cells during inflammation. Actions of ATP are mediated through both ionotropic P2X receptors and metabotropic P2Y receptors. P2X receptor activation causes excitation of visceral afferents; however, the impact of P2Y receptor activation on visceral afferents innervating the gut is unclear. Here we investigate the effects of stimulating P2Y receptors in isolated mouse colonic sensory neurons, and visceral nociceptor fibers in mouse and human nerve-gut preparations. Additionally, we investigate the role of Na(v)1.9 in mediating murine responses. The application of UTP (P2Y(2) and P2Y(4) agonist) sensitized colonic sensory neurons by increasing action potential firing to current injection and depolarizing the membrane potential. The application of ADP (P2Y(1), P2Y(12), and P2Y(13) agonist) also increased action potential firing, an effect blocked by the selective P2Y(1) receptor antagonist MRS2500. UTP or ADP stimulated afferents, including mouse and human visceral nociceptors, in nerve-gut preparations. P2Y(1) and P2Y(2) transcripts were detected in 80% and 56% of retrogradely labeled colonic neurons, respectively. Na(v)1.9 transcripts colocalized in 86% of P2Y(1)-positive and 100% of P2Y(2)-positive colonic neurons, consistent with reduced afferent fiber responses to UTP and ADP in Na(v)1.9(−/−) mice. These data demonstrate that P2Y receptor activation stimulates mouse and human visceral nociceptors, highlighting P2Y-dependent mechanisms in the generation of visceral pain during gastrointestinal disease. SIGNIFICANCE STATEMENT Chronic visceral pain is a debilitating symptom of many gastrointestinal disorders. The activation of pain-sensing nerves located in the bowel wall and their sensitization to physiological stimuli, including bowel movements, underpins the development of such pain, and is associated with mediators released during disease. This work addresses the unstudied role of purine and pyrimidine nucleotides in modulating colonic nociceptors via P2Y receptors using a combination of electrophysiological recordings from human ex vivo samples and a detailed functional study in the mouse. This is the first report to identify colonic purinergic signaling as a function of P2Y receptor activation, in addition to established P2X receptor activity, and the results contribute to our understanding of the development of visceral pain during gastrointestinal disease