Research at KAIST University: Project and Outcomes

Introduction

This blog post is a continuation of the ‘ Research at the KAIST University ‘ post  where we talked about our arrival to Korea and the work plan for the project. This entry focuses on the last days at KAIST, the work achieved in the Biorobotics Laboratory and the outcomes of this research. The goals of the project have been updated and now the parameter testing will only include the dimensional effects. This comprises both width and length of the sensors.

Fabrication

The fabrication process of the samples used in the testing involves different steps. To obtain a broad and comparative dataset, a total of twelve rectangular shape sensors were fabricated with lengths of 30 mm, 60 mm and 90 mm and widths of 5 mm, 10 mm, 15 mm and 20 mm. The thickness of the samples was maintained constant at around 1 mm. First, the nylon skin adhesive elastic fabric was prepared and cut in the corresponding shape. Then, the fabric was placed and aligned on the dispenser table-bed, ready for the deposition of the composite material. For the fabrication, a custom pneumatic dispenser mounted to a 3-axis table was used. The dispenser consist in a syringe, a specialized pneumatic plunger and a pneumatic pump. The composite material is made out of multiwalled carbon nanotubes (MWCNT) in a polymeric matrix of Ecoflex 00-30  (Smooth On, Inc) with a weight percentage of 3.5%wt. The premixed material was introduced in the syringe and then this was mounted to the table and connected to the pneumatic line. The nozzle size, motion speed, air pressure and height of the syringe were controlled to achieve optimum quality of the samples. Once the material was extruded, the samples were introduced in the oven at 70 °C for curing. Finally, the samples were tested using a multimeter to ensure that the specimens were within range.

image                            image-1

Figure 1. a. Fabricated sensor samples using the composite and stretchable fabric. b. Custom automatic dispenser.

Testing Setup

To examine the effects of the dimensional changes in the properties of the carbon nanotube-composite sensor, a parameter testing was performed on different size specimens. The test was performed using the custom extensometer, measuring strain, stress and the electrical resistance of the specimens. The sensor signal was obtained by attaching a 5 mm wide strip of copper tape to both ends of the sensor covering all the width of the composite material. An optimal contact point between the copper tape and the sensor was achieved using a two piece screwed grip. The resistance of the sensors was measured using a constant voltage Wheatstone bridge calibrated with a ratio of 1:4. The positive voltage divider consisted of two resistance R3 and R4 with an impedance of 25kΩ and 100kΩ. The negative voltage divider was composed by the composite strain sensor and a variable resistor (type) that was used to generate balanced Wheatstone bridge. A voltage source of 12 V was used to excite the circuit. To calibrate the Wheatstone bridge the variable resistor was adjusted for each of the samples to maintain the equivalence. The test chosen to study the characteristics of the sensor was a saw tooth dynamic cycle test. This test allows to comprehensively study four characteristics: hysteresis, non-linearity, sensitivity and range and dynamic and oscillatory response. To obtain a broad range of results for the application the test was divided into two parts. A frequency range test was performed at multiple frequencies (0.25 Hz, 0.5 Hz, 1 Hz and 2 Hz) at a fixed strain of 40% of the length of the sample. The second test consisted in a constant frequency test at 0.25 Hz with different elongation percentages (10%, 20%, 30% and 40%). The data was obtained using a cork board (Quanser Q8-USB, Quanser) and the results were processed and analyzed using a MatLab program.

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Figure 2. Extensometer used for testing and its different components.

Results and Outcomes

For the testing of each sensor, 3 key performance indicators (KPIs) were analyzed: sensitivity, linearity and hysteresis. These indicators were chosen as together; they allow for the sensor’s overall performance to be measured. A brief explanation of the method used to calculate each of these indicators is below:

  • Sensitivity: A linear regression line was plotted against the loading and unloading voltage paths (on the graph). From this, the gradient of the linear approximation was calculated and taken as the sensitivity (ds/dV) of the sensor.
  • Linearity: Also from the linear regression line, an Rvalue was calculated. This represents an abstract measure of the fit of the regression line to the data and hence a measure of linearity.
  • Hysteresis: The difference in the measured voltage, over the sensor between the loading and unloading path. This represents the dependence of the sensor current value of previous values.

Whilst each of these values doesn’t offer any particular insight into the sensor performance, these measures combined allow for a better picture to be developed on how varying of dimensions of the sensor affect the sensor’s ability to produce accurate measurements when subjected to a range of frequencies and strains.

The results of the testing were very clear; in general, the longer and the thinner the sensor, the better the sensor performance in all of the KPIs and over the testing ranges.

 

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Figure 3. Graph of the sensitivity against sensor dimension for the different frequencies.

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Figure 4. Graph of the sensitivity against sensor dimension for the different elongation percentages.

Unfortunately, in this blog post, only sensitivity will be considered as the other KPIs are outside of the scope of this blog post. That being said, the sensitivity results effectively convey the overall trend of the data: with increasing length and decreasing width, the performance of the sensors improved.

There are of course limitation of this analysis; the first of which being that not a wide enough range of the test parameters nor sensor dimensions were tested. As a result, it’s difficult to know how far into the extremities of dimensions this trend holds. Furthermore, in relation to the analysis methods; the use of linear regression line in not necessarily the most precise approximation method due to the non-linearity of some of the results. Because of this, error is introduced into the results due to the bad fit of the line to the actual data and it becomes harder to accurately characterize the sensor.

Effects like these are discussed further in the official report on the research with the blog post mostly summarizing and providing some insight into the testing that was carried out whilst Daniel and I were at KAIST.

The next steps for the project are to finalize the results of the testing and write up a detailed discussion of the results such that it can be included as a section within a journal paper. Until that point, the focus will be on analyzing the quality of the data and highlighting any shortcomings in the testing and analysis methods that offer explanation to any outlets found within the data.

The opportunity to travel to South Korea and undertake research at such a prestigious university with such passionate and inspiring researchers has been incredible. We are both incredibly grateful to our research supervisors: Dr. Ali Alazmani and Dr. Peter Culmer, Professor Jung Kim at KAIST and the University of Leeds for putting in so much work to supporting us before, during and after our time at KAIST. As well as this, a big thank you to those researchers within the Biorobotics who made us feel at home and always challenged us to go further in our research.

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Sense and Sensibility: Soft Tactile Sensors

In our Sense and Sensibility research project, funded by Leverhulme Trust, we’re developing the technology to produce soft, tactile sensors Our emphasis is on making low cost, high performance sensors, and crucially developing the basic engineering-science so we can best design, optimise and run these systems.

MagOne – Magnetic Soft Sensing

As an example, here’s MagOne – a single element sensor, using magnetic hall-effect sensors and costing ~£2, easy to make but providing high sensitivity and robustness…

Want to know more? Read a full account in our recent publication in Sensors journal:

Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors

Today our sensing guru Hongbo is presenting recent work on a multi-noded version, ‘MagTrix’ at the EuroSensor 2016 conference in Budapest;

A Low-cost Soft Tactile Sensing Array using 3D Hall Sensors

Soft-Sensing Toolkit: want to build your own?!

We’re just finalising the release of all our designs, software and design tools as an Open Source toolkit for Soft Sensing. The aim is to let the community use what we’ve already developed, apply it and further develop it, this is just the start!

Details on the toolkit coming soon, watch this space!

 

Signal Analysis and the Telerobotics & Control Lab

As part of both the parameter tests Daniel and I are running on the soft carbon nano-tube sensor (see last post) and as a continuation of the research from Leeds, a tensile/indenter testing rig needed to be assembled and the testing (and analysis) software written.

Much of the previous week has been spent putting together the already manufactured testing rig and playing around with some pre-written software. After having set and tidied up the rig (always an important part of research), this weeks aim was to completely write all of the software Daniel and I are going to need over the next three and a half weeks (signal processing etc.).

Fortunately for us, most of the actual test programming had already been written by our supervising masters student (in MATLAB Simulink), requiring only minor modification to fit our needs. The post acquisition data analysis program on the other hand is an entirely different story. As was mentioned in the previous post, prior to our arrival, relatively little quantitative analysis had been done on the existing CNT sensor. As a result, before any useful information can be gathered from any collected data, all of the analysis methods need to be researched, refined and then implemented. Such pieces of information including: the sensors hysteresis during cyclic loading of the sensor, phase lag and resolution.

Aside from the project work Daniel and I have been carrying out, we’ve also had the opportunity to visit some of the other labs on campus. On Wednesday we visited the Telerobotics and Control Lab and saw some of the really exciting work being carried out.

During our visit, we were shown the two main areas of research in the Medical Robotics subgroup, both of which are focused in the area of minimally invasive surgery (MIS).

Single-port Surgery Robot System

The first research project was the Single Port Surgery Robot System (SPSRS). This system, operating on very similar principles to the da Vinci surgical robot, offers three key advantages over the cumbersome and expensive conventional methods for MIS:

  1. It’s bedside mountable, making it highly manoeuvrable.
  2. It can be manufactured at a highly reduced cost relative to conventional methods.
  3. It offers a highly intuitive control system.

The latter of these being achieved through the use of additional joints placed along the length of the operating arm, overcoming the fulcrum effect, and the use of a fully immersive virtual reality-like viewing device (see below).

Flexible Endoscope Surgery Robot System

The other research project was focusing on laparoscopic surgery and, more specifically, the development of a surgical device combining both optical fibres and  surgical tools (i.e. for grasping and cauterisation). There are two fundamental variations in design to achieve this; the first consists of the following components: an over-tube (for directing the internally places tools),  an endoscopic camera, two dexterous surgical arms, navigation system, and an ergonomic master console (see video below).

Robotic Device that assists complex endoscopic procedure

The second design variation was aimed at reducing procedure time and manipulator failure (of the endoscope tools) during laparoscopic surgery through the addition of the Portable Endoscopic Tool Handler (PETH). The PETH can easily be used in conjunction with existing endoscope technologies and enables multiple tools to be used concurrently all through the same laparoscopic insertion tube, as well as providing active multi-directional guidance  for the tools (see video below).

Over the next week Daniel and I hope to begin parameter tests on the CNT soft sensor and, potentially even visit some more laboratories. But for now, that’s everything from us at the Biorobotics Lab at KAIST. Please stay tuned for further updates.

 

 

Research at KAIST University

Introduction

Researcher #1: Hi and welcome to the South Korea blog series where myself, James, and my colleague, Daniel, document our academic and personal experiences during our time at KAIST University working in the Biorobotics Laboratory.

James: Before we explain some of what we’ve been doing here, it’s important we introduce ourselves:

Daniel: Hello, my name is Daniel Nakhaee-Zadeh Gutierrez. I am originally from Spain, but I decided to move to Leeds two years ago to pursue a degree in Medical Engineering. I started working with the Surgical Technologies lab two years ago as a summer intern. My research is mainly focused on the design and manufacturing of soft robotic actuators.

James: And my name is James Kinch and I’m a 3rd year student studying Mechanical Engineering at the University of Leeds. I’m originally from London, but similarly moved to Leeds when I started university. I’ve also  been conducting research with the Surgical Technologies research group in Leeds for the past two years over my summer breaks as part of the Undergraduate Research and Leadership Scholarship scheme. My area of focus is in soft sensing and actuation.

Why are we in the ROK? 

Daniel: The main purpose of our visit to Korea is to create and develop a strong bridge between the University of Leeds and the KAIST university to enable future exchange programs and research projects. At the same time, we are taking part in a small research program that will be explained in detail later on the blog.

What’s going on in the lab here at KAIST?

Daniel: The lab that we’re working in is the bio-robotics lab in the faculty of mechanical engineering at KAIST. The lab is mainly specialized in the use of robotics to aid or rehabilitate the human body, however it hosts a wider range of projects. Some of these projects are explained below:

  • Youngjin – Post Doctorate Researcher: Work on Myoelectric signals and Human-Machine interaction.

He developed two main systems using the SEMG signals from different muscles: A Computer interface for SCI patients based on a computer cursor and a study of the fatigue induced non-linearity on SEMG signals.

  • Soft robotic device to adhere to surface using jamming. They are developing a device based on a gripper sphere, but with the purpose of sticking to surfaces instead of griping objects.
  • A haptic feedback glove using resistance based sensing technics and small vibration actuators to generate feedback.

James: So as you can see, there’s enormous diversity in the types of work being carried out here and it’s all really, really exciting stuff. One of the best parts about coming to South Korea (aside from the food of course!) is that we get the opportunity to peek inside and experience how a laboratory operates in another world leading university for research. We’ll also hopefully get the opportunity to explore, if only briefly, some of the other research groups here at KAIST conducting other incredibly novel research.

What’s your research project in the Biorobotics Lab?

Daniel: The research project that we are taking part in is based on a previous soft sensing research by Hyosang Lee and Jiseung Cho. You can find the research paper in the  link below:

Printable Skin Adhesive Stretch Sensor for Measuring Multi-Axis Human Joint Angles

Captura

The device consists in a highly stretchable Multiwall Carbon Nanotube (MCNT’s) composite  strain sensor capable of measuring multi-axis human joint angles. The purpose of the sensor is to create a cheap and easy to manufacture a device to detect human motion inputs. The sensors are fabricated by extruding Eco-flex 00-30 silicone previously mixed with the carbon nanotubes into an elastic adhesive fabric, using an automatic dispenser. The sensor is a few millimeters thick and shows  great strain sensing capabilities, although it greatly suffers from hysteresis due to the viscoelastic behavior of the silicone.

James: Our work here is going to be focused on running quantitative parameter tests on the already designed sensor. Up until now, the only testing that’s been carried out on the sensor has been very brief hysteresis, and linearity testing with minimal computational analysis. The aim of our time here at KAIST is to essentially do similar testing, but with more thorough quantitative analysis.

We’ll be carrying out a parameter study in order to develop an understanding of how the sensor output is affected by various environmental and physical  factors. Some of the parameters we’re hoping to test are: high/low frequency response, mechanical shock and temperature modulation. These parameters have been chosen as we believe they represent the most susceptible to change during sensor operation and, as a result, are the most important parameters to modulate under controlled conditions. Six weeks isn’t a long time and we’re already a third way through our research, but I’m hopeful we’ll be able to achieve meaningful results by the time we leave KAIST.

The previous two weeks have very much been a period of exploration, much like the next four will hopefully be. For much of the time, our exploration has been mainly focused on understanding how the laboratory works and conducting various pieces of preparatory work for testing, for example: learning how to manufacture the sensors, discussing and planning the parameters to test, setting up the testing equipment and optimizing the testing program.

How is this blog going to work? 

James: So, pretty much from here on out until we return to the UK, Daniel and I are going to be posting regularly on this blog about our own research and experiences in South Korea, about every Wednesday and Friday each week. This way, we keep you updated on everything going on here on a two day basis.

Daniel: On that note, I hope you enjoyed getting to know us a little bit and the work we’re doing/going to do here at KAIST University. We look forward to giving you an insight into all the things we get up to during our 6 weeks.

Soft Robotics, hard challenges

For the last two days I’ve been at the UK-Japan Workshop on Bio-Inspired Soft Robotics in the stunning surroundings of Cambridge University.

It’s been excellent – Dr Fumiya Iida, organising the event, has pulled together some great speakers and we’ve had really inspiring talks from a wide range of backgrounds; biology, physics, robotics, all looking at the area from a different perspective. This morning for example;

 how spiders spin silk webs (Oxford Silk Group)

 how ant feet grip against smooth surfaces (Cambridge Insect Biomechanics Group)

 self organising swarm robots that ‘collaborate’ to move objects towards a target (Sheffield Natural Robotics Lab)

This what I love about being an academic. It’s got me thinking – I’m not sure how this will influence and help my own work, but I am sure that it will!

For my own part, I presented some of our Sense and Sensibility work on soft sensor design and optimisation for soft environments. Hongbo Wang, our postdoc on the project, has done a great demo – still below – showing how we can extract high performance from a super simple mechanical sensor.

MagOne

Initial thoughts on soft robotics themes cropping up from the workshop;

  • Application: there’s still not a clear transfer of soft-robotic tech to industry
    • this might change by treating soft-robotic components as modular (e.g. grippers, actuators)
    • particular industrys like healthcare will benefit and be a driver in the future
  • Design tools: a need for improved design tools for soft structures
  • Control/Computation: new approaches needed to address complexity
    • Reservoir computing
    • Morphological/embodied control
    • Decentratalised/emergent behaviour
  • Interfaces are crucial – for effective interaction of soft systems with hard/soft environments
  • Biology/nature can provide inspiration for the above – and vice-versa, (soft) robotics can help understand how biology behaves
  • Soft: the distinction of ‘soft robotics’ might be temporary – in nature there’s use of both hard+soft structures, its a continuum and both have a part to play..
  • Fabrication: nature builds complex structures simply, quickly, robustly. How to copy that?
  • Healthcare… Soft robotics already a big part in rehabilitation, seems equal opportunity for them in surgery, incontinence care etc.

Last but not least, a big thanks to Fumiya and organising team from the Biologically Inspired Robotics Laboratory and IEEE Soft Robotics Group for supporting. Here’s hoping more of the same next year!

Engineering for continence #5 – Treatment…

My last post was about assessment of incontinence – some thoughts on the technologies involved and challenges/opportunities to be addressed. The two are closely linked – effective treatments need to be informed by good assessment and diagnoses. But it doesn’t stop there and even with the best information available, the effectiveness of current interventions is severely limited by technology. This is a huge topic but I’ll try and scratch the surface while keeping it concise!

A spectrum from management to treatment

Management and treatment of incontinence are often treated as different topics but it seems, from my perspective at least, that they lie at ends of a spectrum. Management generally implies performing some regular action (e.g. daily use of continence pads or catheterisation) to minimise the functional impact of incontinence. Treatment on the other hand is often viewed as a discrete event with a fairly binary outcome being a return to ‘normal’ function; you have ‘treatment’ and you’re ‘fixed’. This is particularly common with surgery, perhaps because of the physical nature of the intervention. However, the reality is that many treatments don’t provide a full return to normal function (so some management is still required) and the effects aren’t always permanent but degrade over time. So, it’s natural to ask ‘why’? Can we improve the effectiveness of treatments in the short and long term?

How to intervene? 

After assessment, treatment options vary depending on physical health, age, mobility, other potentially confounding conditions….it’s a long list. In general though, the accepted approach is to start with conservative interventions before committing to more radical options. It struck me that a number of factors lie behind this:

  • The clinical aim is to achieve the best functional outcome for the patient…
  • …while minimising potentially unnecessary risk/trauma (e.g. surgery under general anaesthetic)
  • Time is typically not a critical factor (in terms of the condition changing)…
  • …which gives opportunity to explore more conservative treatment options first
  • It’s often difficult to predict which treatment strategies will be effective, and if so for how long
  • Last but not least; conservative treatments are often as effective, or more so, than radical options

Cases in point…

Taking the example of a person with obstructive defecation resulting from ineffective function of the anal sphincter and pelvic floor muscles (as discussed in previous posts). The patient experiences difficulty defecating and also experiences leakages which are difficult to predict.

Dietary changes and pelvic floor retraining: The consultant sees opportunity for conservative treatment and refers the patient to a nurse specialist. Firstly, the person’s diet and lifestyle is assessed using a food diary. The nurse firstly recommends some dietary changes (e.g. ensuring appropriate amounts of fibre are consumed, avoiding excessive caffeine, etc.). This is combined with pelvic floor exercises which aim to retrain the actions of the pelvic floor and voluntary anal sphincter so they are both coordinated and generate the right pressure and movement. It’s important that the patient practices frequently enough and in the right way (i.e. recruiting the correct muscles – pelvic floor rather than abdominal).

If this intervention is effective it’s ideal for patient and the healthcare service; minimum risk to the patient, cost effective for the health service and the patient has been empowered to manage their condition. But what might cause this intervention to fail? A big factor here is that it’s reliant on the patient being actively involved in what is likely a slow process. It means rigorously doing exercises several times a day, over a course of weeks and months, when changes in function may be subtle and difficult to observe. So motivation is key – it’s difficult to be persistent when you’re getting no sense of achievement/improvement. Increasingly biofeedback devices are employed to help, patients are given a system which provides feedback on muscle strength – providing much needed feedback to guide practice. Still, it’s not for everyone (current systems typically take the form of an instrumented plug in the anal canal) and to be truly effective they must provide feedback in a suitable form for the patient – so factors such as age, ‘tech-savviness’ and culture all play a big part.

Sacral Nerve Stimulation (SNS): If more conservative measures fail, SNS provides an option before full-blown surgery in patients with a weakened but functional anal sphincter or some nerve damage. In brief it works by electrically stimulating the sacral nerve (through implants and a small control unit worn by the skin) which activates the (external) anal sphincter and surrounding muscles and help preserve continence. The stimulation is then paused when the person wants to defecate. After initial fitting the system can be tuned by adjusting the electrical stimulation (it’s frequency, intensity and location on the sacral nerve) to obtain the best outcome.

However, the exact mechanisms by which SNS works aren’t well understood, it’s a slightly enigmatic treatment. Interaction with the nervous system, even when isolating a particular region like the sacral nerve, remains complex and difficult to predict. So when SNS is successful, the intervention can rapidly bring life-changing benefits to the patient at low risk and this underpins its popularity, despite the fact it remains relatively expensive for the healthcare service. But some patients just don’t respond well to SNS, despite all indications suggesting that they should. Frustrating for the patient and clinical team involved.

Surgery – Ventral Mesh Rectopexy: If more conservative treatment options have failed then surgery may be considered. This clearly isn’t taken lightly, since risk to the patient and cost to the healthcare service significantly increase; there’s always an inherent risk of going ‘under the knife’.

Ventral rectopexy surgery involves using a mesh (like a long strip of stiff plastic netting) to help support a dropped pelvic floor. The mesh is positioned using a minimally invasive ‘keyhole’ procedure (laparoscopic surgery) in which the surgeon sutures one end of the mesh to the bottom of the pelvic floor near the anus and the other end is attached to the sacrum (the lower part of the pelvis). The mesh is intended to prevent the pelvic floor dropping because it acts in tension from its fixed anchor, like the cable on a suspension bridge. For this to be effective it’s clear that the length on the mesh are critical. If the mesh is too long it won’t provide any tension so the pelvic floor will still drop. Alternatively if the mesh is too short there will be excessive tension on the mesh, so the pelvic floor will sit too ‘high’ which can cause a whole new set of problems for the patient. A confounding factor here is time; following surgery, soft tissues around the mesh will begin to integrate into it’s structure, changing it’s mechanical properties and often causing it to shrink. So defining an acceptable envelope for mesh length (and tension) relies heavily on the surgeon’s experience and judgement and is critical in achieving an effective outcome.

Ventral rectopexy surgery can bring great functional outcomes to the patient. However, if it fails to bring the expected improvements, or worse causes other problems for the patient, the implications are profound and can require follow-up surgery to adjust or remove the mesh.

Better Integration?

It seems there’s a common theme in reasons for failure; poor integration of technology with the human body. This includes a wealth of ‘domains’, from the physical (e.g. meshes supporting the pelvic floor), electrical (or more strictly nervous system with SNS) through to the less tangible but equally important emotional (e.g. designing devices to give effective feedback for rehabilitation).

So there’s an inherent need to design technology which can better mimic and integrate with the human system. Easier said than done, but to me this has to be a priority if we are to improve on the treatments currently available for those with incontinence.

Engineering in continence #4 – Assessment

It’s been a while since my last post, where I laid out some thoughts on understanding (in)continence from an engineering viewpoint. Essentially translating my various experiences into a context and form with which I’m familiar. As an academic researcher working in a multidisciplinary area (clinical engineering) this is an important skill, but doesn’t always come easily – it’s very easy to get the ‘wrong end of the stick’!

So, accurate interpretation and communication of information/events/experiences is key. But before this placement, I hadn’t appreciated how much this applies to clinicians, in particular those looking to assess people with incontinence. I’ve spent time with radiologists, physiologists, specialist continence nurses and consultant surgeons, in each case different tests are conducted, firstly to understand the problem and secondly to inform treatment/management of the condition.

Radiology: a key assessment for those with bowel problems is proctography – a technique which records a person’s bowel movements using a time-series of CT images and a simulated stool composed of barium paste (highly visible on CT). The person is asked to sit on a comode, then try number of exercises related to either ‘holding on’ or defecating. As you can imagine, generally not a pleasant experience for the person involved – but it can bring highly valuable information. I spent a morning seeing the proctogram list and saw a variety of features including pelvic floor prolapse, rectoceles, enteroceles and puborectalis function. The technique is useful because the moving images (about 4 per second) reveal the dynamic function of the bowel, rather than just a static image of its anatomical structure. You see rectoceles ’emerge’ from the rectum as the person ‘strains’ and the pressure within the rectum increases. You can watch the anorectal angle change (or not) as they attempt to defecate. These are all dynamic events and therefore need dynamic assessment. However, these methods aren’t without their drawbacks. The discomfort and setup of the test (we’re not generlly used to defecating in public, let alone surrounded by a CT scanner) mean that sometimes you don’t get a ‘natural’ response from the person involved. Secondly, the challenge here is interpretation – many features identified by the radiologist are near invisible to my untrained eye, for example the action and degree of movmement of the puborectalis muscle, or intussusception (where the rectum folds in on itself). The findings are valuable, but subjective.

Physiology: physical examinations from physiologists are routinely used to complement imaging information from radiology. For bowel problems, two techniques are commonly employed, anorectal manometry and Ultrasound Imaging. The latter is fairly standard practice, a radial ultrasound probe is used to scan the anal canal and surrounding structures. This shows 3 key anatomical structures, the anal canal, the internal anal sphincter and the external anal sphincter. It can reveal features such as tears in these structures (for example as a result of childbirth). However, the information is limited to structure and does not provide any indication of function. This is where manometry is invaluable in recording the function of the anal sphincters through the pressure they generate against a catheter probe. The pressure sensitive probe is inserted into the person’s anal canal and used to record different states, from ‘relaxed’ to coughs and squeezes. The relaxed state provides a baseline for comparison of the elevated pressures you would expect when they cough for example. A range of probe technology is available – the system I saw used water pressure to record 10 points along the length of the probe. Solid state systems are also available with sensing elements around the probe circumference and along its length. The output from the system is a pressure map of the rectum and anal canal, changing over time as a result of the person’s actions.
It’s interesting to note that while this provides quantitative data, there remains a significant amount of interpretation to transform it into a meaningful clinical outcome – clinicians don’t tend to work in Pascals!

Opportunities…

That’s two of the main stays of assessment, but some common themes really stuck out for me;
*Functional assessment is essential to understand the complex features of incontinence
*Assessment methods are often intrusive and off-putting for the person involved
*Unnatural positioning and social tension may compromise the test results
*Assessments require skilled interpretation to relate images/readings to the complex 3d anatomy
*It remains challenging to combine outcomes from different modes of assessment to get a full picture of a person’s condition and function (e.g. proctograms showing prolapse with manometry showing poor sphincter control)

So, while current assessment methods are instrumental for incontinence treatment it seems there’s definitely opportunity to improve things; to reduce invasiveness and improve the quality and analysis of the information obtained.
Engineers, scientists, clinicians, time to get the thinking caps on!

Engineering In Continence #3 – Making Sense of the System(s)

The start of some more detailed posts on my placements looking at incontinence healthcare. First, some initial thoughts on the complexities of the bowel and bladder systems involved….

Pipes and Plumbing?

In very broad terms,  the bowel and bladder act as containment systems; with pressurised storage vessels, interconnecting pipes, and valves. You can see why people often refer to ‘problems with the waterworks/plumbing’. However, looking closer, I’ve seen how the reality is complicated by a few key factors:

  • Motion: the components of the urinary and faecal systems are highly mobile (moving with the tissues and organs inside the body). Normal function depends on the right degree of movement, regulated by structures like the pelvic floor. However, excessive or restricted movement can upset the balance and lead to incontinence.
  • Material Properties: the components don’t just move, but their material properties allow them to deform, stretch and contract. These can range from simple linear scaling (e.g. the bladder swelling to hold more urine) to complex non-linear transformations leading to fundamental changes in geometry (e.g. prolapse where the walls of the rectum ‘invert’)
  • Sensing and Actuation: the majority of the components in both the bowel and bladder systems are active – by which I mean they contain musculature, enabling them to actively change shape/force and sensory elements providing information on pressure, position, fill levels etc.
  • Coordinated Control: the components of the urinary and faecal systems can be broadly divided into two categories corresponding to how they are controlled; either under voluntary (somatic) or involuntary (or autonomic) control. Critically, the two ‘sub-systems’ are closely coupled; normal function depends on both working effectively and in close coordination to maintain continence and enable urination/defecation. For example, the urethral sphincter has an inner part (under involuntary control) and external part (under voluntary control) – both components must sufficiently ‘relax’, at the same time, to enable urination.

It’s all connected…

So, in conclusion, the faecal and urinary systems are far from ‘dumb’ pipework but actually semi-autonomous/smart systems with the ability to monitor and change their own state. In turn this means there are numerous opportunities for things to go wrong; upsetting the balance in these tightly-coupled, interlinked systems is likely to have an effect on their overall function.

Phrasing it in these terms of ‘function’ and ‘sub-systems’ is all very well, and all very ‘engineeringy’, but risks loosing the human angle. That is, the faecal and urinary systems are highly complex and can be effected at many levels but the ultimate outcome on continence is profound for the person involved.

On writing this, I’ve realised I need to revisit this in more detail, to fully consider the urinary and faecal systems individually. One for another day though…!

Engineering In Continence #2

I’m roughly halfway through my project to observe incontinence healthcare from an engineering viewpoint. So far I’ve been focussed on healthcare services, visiting various clinical settings within NHS Leeds Teaching Hospitals Trust (later I’ll look specifically at patient and commercial interests). It’s been incredible, informative and moving, now seemed a good time for a first reflection on my experiences….

A privileged insight

Up front I need to say how privileged I’ve been; from surgery to clinics, I’ve been welcomed by staff and patients alike. People have gone out of their way to help, sparing lunch breaks, making early starts and making a real effort to explain the often (seemingly) perplexing processes involved in incontinence care. At a time when the NHS (and more specifically its frontline staff) are under huge pressures (political, economic, you name it) this is all very humbling and goes to highlight that the people involved don’t so much work for the NHS as for the patients and their benefit. Which is where I hope to come in – by identifying opportunities where engineers and scientists can help improve things for all concerned. No pressure!

First-hand experience, first-rate information

As an academic, I’m used to ‘researching’ new fields; seeing what’s been done before, the current state-of-the-art (a.k.a. who’s beaten you to it!) and scoping out ‘gaps’ to work on. Now, more than ever, the reality of this can mean sitting with your laptop, sifting through an academic search engine (Google Scholar, PubMED, etc.) and lots of articles.

“In the UK, 1 in 4 people will have bladder problems, 1 in 10 bowel problems, this doesn’t just affect the elderly – 5 million under 24 year olds are affected and the associated healthcare costs are huge for the NHS”. You’ve been thorough when your eyes go red, and exhaustive when you fall asleep on the keyboard.

The whole point of this project was to get out of my academic ‘comfort zone’ and experience things first-hand, seeing the day-to-day realities and not just as a passive observer, but being able to repeatedly ask ‘why?’ (much like my 3 year old daughter).

This is where the healthcare professionals have been fantastic – tolerating me scribbling and sketching away in my notebook (often adding their own – much better – diagrams) and humouring strings of (often daft) questions with considered replies that have really transformed my understanding of both incontinence, and the healthcare system surrounding it. As for the daft questions – sometimes asking the obvious does help unpick accepted ‘convention’ (does it really have to happen like that?) – then again other times it’s probably just me…

So while the background reading is obviously necessary, experiencing and understanding what this means in reality to individuals with incontinence and their clinicians adds so much. My hope is that I can convey some of this to spark interest from scientists and engineers who might not otherwise have thought of applying their skills in this area – let’s face it, ‘incontinence’ is still surrounded by taboo – but for want of a better phrase, it needs exactly those people to get stuck in and make a difference.

Joining the dots

I’d intended to write about this project sooner, perhaps after each clinical placement, but it hasn’t quite worked out that way. I could blame the competing demands of academic life (those project reports won’t mark themselves…) but if I’m honest, it’s taken time to make sense of my experience so far. In particular, how do the various services join up to form the ‘patient pathway’, the overall healthcare system around incontinence? While my ultimate focus is at a technical level, it’s become increasingly clear that without an appreciation of this background, you’re trying to build a Lego set without the manual… So, what’ve I seen so far, and how does it fit together? The sketch below shows my simplified take, from the perspective of a imaginary patient with bowel problems. After visiting their GP, they’re referred to a consultant colorectal surgeon who sets appointments with radiology, physiology and maybe endoscopy to get a full picture. At this point the patient may be offered surgery, but it’s a last resort and the preferred option is always more conservative treatments, such as those offered by nurse specialists in bowel and bladder management.

What Next?

That’s just a snapshot of my experience to date, in future posts I’ll talk in more detail about each of the areas above, the clinical challenges and the possible opportunities for us, and others, to work on…

Engineering In Continence #1

impressmaniconIncontinence places a huge burden on healthcare systems and has a major impact on quality of life for thousands of patients of all ages in the UK. It receives little attention within the medical research sector  and current technological interventions are limited in their function and effectiveness.

A few weeks ago I started a project funded by the Wellcome Trust through its Institutional Strategic Support Fund (ISSF). The aim is to improve understanding of incontinence assessment, treatment and management, using an engineering perspective to help identify, interpret and ultimately address the clinical and patient challenges. I’ll look to provide a detailed view of incontinence across the patient pathway encompassing patients, healthcare professionals and industry representatives. This will centre around visits to shadow clinicians at St James’s Hospital in Leeds to experience first-hand the practices involved.

Reporting via this blog, a regular Twitter stream (@PeteCulmer) and articles in medical and scientific journals and magazines, the project aims to share its findings and raise the profile of incontinence within the scientific and engineering communities. Ultimately I hope to reach a broad audience, boost awareness of this critical area of need and encourag interest in research to address it’s challenges