Kidney stones are very common — larger stones often need surgery to remove them. John Cousins, 46, a divorced father of two who lives near Southampton, came up with a novel way to help surgeons during his operation, as he tells Angela Epstein. John Cousins (pictured) did not realise he was suffering from kidney stones until he collapsed from an unrelated condition last November . THE PATIENT . My kidney stone took me by surprise — I only discovered I had one after I collapsed with an unrelated condition last November. I run a 3D printing company which makes bones out of plaster of Paris for surgeons to use as practice models for complex orthopaedic operations. During a presentation to surgeons, I was suddenly floored by an agonising pain radiating across my lower stomach. I was taken to Southampton General Hospital, where I was shocked to learn I had an appendicitis. My appendix was removed that night. However, scans also revealed a large stone in my right kidney. Despite its size — 3.5cm by 2.5cm — it had given me none of the usual symptoms, such as pain or blood in the urine. Apparently it had developed because I had a kidney infection, which I didn’t even realise. The doctors said it might grow even bigger, so I was told I’d need further surgery to cut out the stone. It was a lot to take in while also facing having my appendix removed. But I’ve had operations on my knees, back and for hernias, and after my appendix agony I didn’t want even more pain from a growing stone. After they removed my appendix, I began wondering whether 3D technology might be helpful with my kidney operation. I discussed it with my consultant, urological surgeon Bhaskar Somani, suggesting that a life-size model of my kidney with the stone inside might give him accurate information about my operation. After he collapsed, John (pictured) was taken to Southampton General Hospital where he was diagnosed with appendicitis and had his appendix removed . He’d heard of 3D being used in orthopaedic operations such as hip replacements but, as far as he knew, it hadn’t been used with this kind of procedure. He agreed it might help — anything allowing a surgeon to visualise the area in more detail could only make surgery quicker and more accurate. I wasn’t due to have the stone removed until January this year, so, after taking two weeks off work to recover from the appendix operation, I began work on the model. The machine we use for 3D printing, known as an isodo3D, used images of my kidney from CT scans to recreate a model, slice by slice, using layers of plaster of Paris half a millimetre thick. John used images of his kidney from the CT scan to recreate a model, slice by slice using plaster of Paris (pictured). This allows the surgeon to complete surgery faster and more accurately . These layers were then laid on top of each other. The model was made in three coloured parts, so it could be taken apart like Lego pieces. This way, Mr Somani could work out the best angle to go into the kidney with his instruments. This planning can reduce operation times because it means less chance of having to rely on trial and error. The model took four hours to make and I was astonished when I saw the finished product — particularly the size of the stone. I couldn’t understand how something that big hadn’t caused me trouble. When I woke from the three-hour operation, I was a bit sore but was walking around within hours. I was in hospital for five days and had the stitches from my tiny wound taken out two weeks later. The replica of his kidney that John (pictured) created, allowed Mr Somani to work out the best angle to go into the kidney with his instruments . The soreness lasted a few days, but painkillers helped, and I was back in the office within ten days. I don’t know whether that’s because of the kidney model, but I like to think so. I’m planning to make more models for Mr Somani — for ten patients with kidney stones and ten with cancer. They cost £123 — but if it shortens operations and therefore reduces infection risk, it could be of massive benefit to the health service and save money in the long run. THE SURGEON . Bhaskar Somani is a consultant urological surgeon and specialist in endourology at University Hospital Southampton NHS Foundation Trust. Kidney stones occur when waste products removed from the blood form crystals, which over time form hard stones. If they’re not completely blocking tubes in and around the kidneys, they should pass naturally within five weeks. But larger stones can get stuck — they can be extremely painful and lead to infections. John (pictured) is now planning to make more models for Mr Somani, costing £123 a piece . John’s was a large stone that would have been hard to pass and he needed an operation, a keyhole procedure called percutaneous nephrolithotomy. It’s quite complex surgery — there is a risk of bleeding because the kidney has such a rich blood supply. In up to 5 per cent of cases, patients need a transfusion. A CT scan and X-rays are taken beforehand to pinpoint the exact location of a kidney stone. But I felt having a 3D model as well would give us even more detail: I’d be able to hold the model, take it apart, see the exact location of the stone and plan the precise angle of our surgical instruments. I kept the model throughout the surgery to consolidate what I was seeing on screen. We started the procedure by passing a camera — a cystoscope — through the urethra and up into the bladder. This meant I could see the stone on a screen. Then John was turned on his front and I made a 1cm incision on his right-hand side, just below the ribcage in his back. Then we punctured the kidney with a fine needle, which helped create a tract, or tunnel, for us to access the kidney. This was done under X-ray guidance. Next, I passed a hollow tube known as a dilator into this tract, to enlarge it, so we could then insert a telescope, allowing images to be produced on screen. Then, using ultrasound energy pumped through a tiny probe, we broke the stone into fragments, before sucking them out using a pump inserted through the small puncture in the back. Throughout the procedure, having the model as a point of reference was very useful, allowing me to visualise in 3D what was happening at each stage. Typical risks of the procedure include excess bleeding, as well as injuring the structures surrounding the kidney, but having a model helps minimise risks. John has also created a model of a kidney with a cancerous tumour (left). The right-hand picture shows the model of John's own kidney stone . I hope this technology soon becomes widely available. I carry out around 250 kidney-stone procedures a year, around 30 of which are large and complex. The model could speed up procedures like this by 30 minutes as it will take less time to plan how to access the kidney. This in turn could reduce infection time and complication rates. It could be helpful when removing tumours, too. It’s also useful to show the patient a model when explaining the procedure, and it could also help in training the surgeons of tomorrow. ANY DRAWBACKS? ‘There’s no doubt that having a model to study before surgery and then to refer to a during an operation can only increase its success,’ says Christopher Eden, a consultant urologist at the Royal Surrey County Hospital in Guildford. ‘Kidney stones — especially large ones — can involve fairly complicated surgery. And, with keyhole surgery, when you are operating with a telescope, you need to plan in a methodical fashion beforehand. A model like this is certainly the way forward for this sort of surgery.’ The surgery costs between £10,000 and £12,000 privately, and is a similar cost to the NHS.
Kidney stones are very common and often larger ones need to be removed . John Cousins, 46, has come up with a unique way to help surgeons . He used images of his kidney from CT scans to recreate a 3D model . This lets the surgeon to see the area in more detail and speeds up surgery .