Category: Blog

Final blog post

In the last couple of weeks we have been manufacturing our final prototypes in preparation for cadaveric testing, fabricating the improved silicon training device and creating a short video summarising our project.  Our final cadaveric testing day was at the end of the 8 week internship.

Final prototype

This is the final prototype we used in the cadaveric testing.  We made two sets of the components in case any part failed in the testing.  For this prototype we decided to manufacture the pins out of steel rods as oppose to aluminium.  This was to improve the overall strength of the design.

We had five different springs of varying stiffness, each spring had a set of pipes.  For each spring we calibrated the system and created a scale on the inner pipe with red and green tape.  The green tape indicated an applied force of below 135 N and the red tape of above 135 N.

For the smaller components such as the steel rods we made 5 different copies to avoid any complications during testing.

 

Final prototype

 

 

 

 

 

 

 

 

Silicon model 

This is our improved training device.  The purpose of this is to work as an alternative to the fabric box trainer and to work as a model of the abdominal to train people to use the gasless laparoscopic lift equipment.  It is fabricated from a composite of silicon and spandex, plywood and Perspex.

Cadaveric testing

We asked 6 surgeons to all carry out a conventional laparoscopic surgery and a surgery using the lift equipment, with our load meter device.  The load cell was used to measure the force applied to the abdominal wall.  After the initial insufflation, the geometry of the abdomen was scanned using Artec Spider 3D scanner.  When the surgeons were happy with the cavity and field of view given from the lift device the force on the abdominal wall was recorded using the load cell, the 3D scanner was then used to record the geometry of the enlarged abdomen.   Throughout the day we collected lots of evidence which we are excited to evaluate in the future.

The last 8 weeks have been such an interesting insight to the world of research, we have all very much enjoyed the project and are very thankful for the opportunity!

 

This is the second blog from our Engineering Summer Interns on their project for Gasless Laparoscopic Surgery.

After the initial designs for the force measurement device, several prototypes were made for the two aspects of the project.  We went through several iterations to improve strength and fit of the different parts that interface with each other.

PROTOTYPING

The next step in this project was to manufacture the initial prototype as a proof of concept.  Our device was made using materials that were readily available to us and made use of 3D printing.

Components of the prototypes:

Two concentric pipes were cut to length, and together they house the spring. We found that the 3d printed designs shrunk slightly when printed so the dimensions had to be readjusted by hand.  The spring was an off-the-shelf component that could hold a force equivalent to the retraction force applied during gasless laparoscopy.  An electronic force measurement device was also incorporated into the prototype for testing during the clinical trial.

The spring was then calibrated to a simple scale to show if the force being applied to the abdominal wall was excessive.  Using a colour coded scale, with green signifying a force in the appropriate range and red to show that the force is too high, we could lower the risks of damaging the equipment and causing abdominal wall trauma.

 

 

 

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    Figure 1: Final prototype

 

 

Testing of prototype

The ability for our 3D printed attachment to withstand the load was a point of concern for us.  Even though hand calculations said it was strong enough, we wanted to carry out load testing to ensure that this would be the case.

Fortunately, the part in question did not fail, but the point of attachment to the test bench did.  This raised the question of whether the cadaver table would be able to hold the whole gasless laparoscopic kit during the cadaveric trial.  A preliminary visit to the dissection room before the trials is planned to ensure that the test can go ahead as planned.

The bend of the arm can be observed in the photograph.  However the aluminium beam that attached the device to the table failed under the moment at 14 kg of load.

 

 

 

 

 

 

 

    Figure 2: Testing the prototype with weights

 

 

The abdominal wall box trainer

The initial prototype for the box trainer was fabricated from two pieces of perspex and two sheets of silicone rubber that come fully formed.  Below the pictures demonstrate the initial prototype being used with the hook of the device.

We continued this by using the newton meter to demonstrate the cavity created when the expected surgical load of 140 N is applied.  There were few problems with this model, the sheets of silicone are larger than the perspex sheets and as there is no air gap between the table and the sheets, a vacuum is formed under the sheets when lifted.  This is not an accurate representation of what happens when the abdominal wall is lifted.

 

 

 

 

 

 

 

    Figure 3: Testing the simulated abdominal wall

 

To improve the prototype, a custom mould of silicone rubber has been cast and is in the process of curing.  The mould can be seen in the pictures below.

 

 

 

 

 

 

 

Figure 4: Silicone mould

 

Next Steps

We are working towards a cadaveric study in the next few weeks where we will be able to assess the effect that our load device has on the force applied, by surgeons, to the abdominal wall.  During this trial we hope to acquire not only load data but also 3D scans of the cavity created in order to quantify the difference in volume created by gasless and conventional laparoscopic surgery.

Gasless laparoscopy is a new development in the field of laparoscopic/keyhole surgery. A mechanical device is used instead of carbon dioxide to lift the abdominal wall creating a cavity for the surgeons to work within. In rural locations the infrastructure and equipment may not be available for conventional laparoscopic surgery, however since gasless laparoscopy requires less specialist equipment it is much more accessible and more affordable. The problem with gasless laparoscopic surgery is that the amount of force required to lift the abdominal wall sufficiently is dependent on the surgeon’s experience, and may cause abdominal trauma if done incorrectly. No quantitative or qualitative feedback mechanism is known that shows if the retraction force on the lift device is sufficient to create the required cavity.

    A ‘tent like cavity created by the lift device

 

 

 

 

 

The aim of our project is to create a mechanical force sensor for a lift device to provide an estimation of the force a surgeon is exerting on the abdominal wall. The force feedback from the sensor will help surgeons to avoid abdominal wall trauma by preventing them from using too much force whilst lifting. The sensor must be entirely mechanical so that it can be used in regions with limited electricity supply. Secondary goals of the project are to create an abdominal wall box trainer that will simulate the mechanical properties of the abdominal wall – much better than the piece of fabric that is currently in use.

 

 

    3D model of current design

 

 

 

 

We are currently 3 weeks into our project and are well on our way to
creating a prototype of the device. To begin, we conducted a literature review to condense all the critical information, such as the mechanical properties of the abdominal wall, which has been published in journals. The current lift system was also modelled in a 3D design software as it has not been well documented, making it hard to reproduce. Several concepts were designed for the force measurement device and the final design shown is now being manufactured so that we can begin the testing process.

    Final concept 

We have also spent time researching materials that have similar mechanical properties to the abdominal wall to be used in our box trainer. We are now in the process of learning how to fabricate some reinforced silicone that has similar properties, and is readily available.

    Box trainer currently in use

• Liao, C.H., Kuo, I.M., Fu, C.Y., Chen, C.C., Yang, S.J., Ouyang, C.H., Wang, S.Y., Chen, S.W., Hsu, Y.P. and Kang, S.C., 2014. Gasless laparoscopic assisted surgery for abdominal trauma. Injury, 45(5), pp.850-854.

Only one week passed after we arrived back from the Sierra Leone visit the month before we back on the trail, this time heading for India. A contrasting land to Sierra Leone, but one that in parts shared many of the same challenges and opportunities. This time, we visited India for 2 weeks. The first week was dominated by clinicians and engineers from Leeds co-hosting an Innovation Workshop at the engineering and science university, Karunya University, in Coimbatore, Tamil Nadu. This 3-day workshop, co-hosted with Leeds GHRG-ST, Karunya and Harvard Programme for Global Surgery and Social Change (PGSSC), set out to teach the university’s engineering students the principles of clinical need identification, concept development and pitching solutions. 12 teams of students presented their concepts and will be supported to develop these projects further, all with the aim of improving healthcare for underserved populations in India. Before we left Coimbatore, we visited a local medical device manufacturing company called Stann Biomedical and saw how our partners could collaborate with industry to provide devices and equipment for underserved hospitals.

After the workshop, we ventured to the North East of the country, some 4 hours by air. Along the way we witnessed our in-country partners undertake ‘surgical camps’ to deliver surgical care to those in need. The North-Eastern states are some of the most underserved in the country and have very weak healthcare systems with severely limited surgical care provision. Our main focus is in the state of Arunachal Pradesh, on the Indo-China border. We spent vast amounts of time driving between the states in the North East, as the roads are extremely poor and distances take significant time to cover.

We spent time in the capital of Arunachal Pradesh, Itanagar, where we had meetings with one of our collaborators at the Director of the Tomo Riba Institute of Health & Medical Sciences. It is associated with the state’s biggest government hospital, some 250 beds, which is functioning rather well and can provide a broad range of surgical services. He plans to establish the state’s first medical college here with an initial intake of medical undergraduates in the Autumn of 2018. He has worked hard to identify key faculty members and has secured funding from central government to deliver his vision.

We spent the remaining few days of our trip visiting district hospitals and primary health centres to establish the state of surgical and diagnostic services in the Western district of the state. We witnessed further surgical camps including the provision of gasless lift laparoscopic (keyhole) surgery (GLLS), designed to reduce the cost of this minimally invasive technique and give thousands of patients access this surgical option. We saw key diagnostic facilities to provide services to peripheral populations and discussed how these could be harnessed within a referral pathway to larger district hospitals.

A truly fascinating visit, India is a land of extremes with some populations severely underserved. The people endevouring to establish a brand new medical college, and those delivering surgical care to some of the most remote populations are inspiring. From the visit, the main areas of focus for the groups work include contributing to the education and delivery of the newly established medical college and undergraduate trainees, establishing Tomo Riba Institute of Health & Medical Sciences as a centre for laparoscopic training, and creating an evidence base to inform the wider adoption of GLLS for underserved patients across India.

 

 

 

 

This research was commissioned by the National Institute for Health Research using Official Development Assistance (ODA) funding.

The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

As the snow and cold weather began to take a grip on the UK, the NIHR GHRG-ST team busily planned our initial priority setting visit to Sierra Leone. Assembling a team of clinicians, health economists, trialists and global health scientists, we set off for West African country with a packed schedule in mind, determined to make the most of our visit. When we arrived, the contrast from the Yorkshire winter was stark, with average temperatures of 28 degrees Celsius we landed in Lungi International Airport and took the ‘Sea Coach’ across the Tagrin Bay to the capitol, Free Town. Here we began our visit with meetings in the main government healthcare facility Connaught Hospital and the College of Medicine and Allied Health Sciences (COMAHS), University of Sierra Leone, the only medical school in the country. Connaught Hospital is a large establishment with over 120 beds and is the capitols main referral centre. Despite this the hospital suffers significant constraints, from funding to post graduate training, and frequently can only offer limited services as it struggles in an attempt to meet the huge health burden of the city and country.

In the following days, we visited a range of healthcare facilities in Freetown including a well-functioning NGO hospital, Emergency Hospital. Here we say what may be possible given sufficient resources and innovative financing strategies. We also visited the Ministry of Health and Sanitation and our evenings were often filled with meetings with officials from the government and other organisations including the World Bank, covering topics such as policy planning and strategy, healthcare economics expertise building, healthcare financing and service provision.

After a few days in Freetown, the team packed up and moved in-land to the northern district of Tonkolili. Here we had visits with local district planning officers and discussed where the groups work could contribute best at a district level. We were hosted by an NGO hospital called Masanga Hospital. It is a severely constrained hospital, yet functions quite well despite this, and provides subsidised healthcare for local populations and also hosts the Surgical Training Programme (STP) from the NGO CapaCare. Here we saw how the trainees are trained, and what a huge difference this makes to the provision of surgical care at the hospital.

Following a couple of days in Masanga, observing and contributing to the STP and observing the delivery of surgical care at a general district hospital, we returned to Freetown for final meetings with coordinators and leaders from the National Surgical Forum of Sierra Leone. The National Surgical Forum are a collective of stakeholders from surgeons, healthcare workers, policy makers, patients and industry who all have an interest in improving surgical care for the Nation. Their primary role is to establish and implement a National Surgical Plan, which sets out the national strategy to achieving universal access to timely, safe and affordable surgical care. The NIHR GHRG-ST aims to be involved and contribute where needed.

Sierra Leone is a fascinating country and the people are warm and welcoming. The people trying to deliver surgical care in such challenging environments were so inspirational. The main areas the group felt our research can contribute include enhancing surgical postgraduate training, reducing infection after surgery and improving the management options for patients with lower-limb fractures and chronic wounds. We are now looking forward to working with our in-country partners to implement our initial projects aimed to improve surgical care and outcomes for the patients of Sierra Leone.

Inpatient ward at Connaught Hospital Freetworn
Operating theatres at Connaught Hospital
Sunset at Masanga Hospital
Surgical Training Programme at Masanga Hospital. Bowel anastomosis skills course
Main thoroughfare in Connaught Hospital

 

This research was commissioned by the National Institute for Health Research using Official Development Assistance (ODA) funding.

The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.