Surgery



Surgeons use 3D printed kidney to simulate surgery before operation





For the first time, surgeons have used 3D printing to produce exact models of tumour- containing kidneys, allowing them to simulate surgery prior to the real operation. These models can be personalised to each patient, giving doctors a 3D model of each individual’s tumour.

Kidney cancers are the 8th most common cancer affecting adults, accounting for around 3% of all cancers in Europe. In 2012 it was estimated that there would be approximately 84,400 new cases of kidney cancer with 34,700 deaths. It is usually treated surgically, but the operations can be stressful, and speed and accuracy are essential.

The ability to produce exact 3-dimensional models of objects means that 3D printing is set to revolutionise many fields. A group of surgeons from Kobe University in Japan has combined the 3D imaging capabilities of Computer Tomography, with 3D printing, to produce exact scale model of kidneys prior to surgery. This allows surgeons to practice surgery in difficult kidney cancer cases. So far they have produced ten 3D kidney models to assist in kidney cancer operations.

The group used computer tomography to produce a 3D scan of a diseased kidney. They then fed this information into a commercially- available 3D printer to produce a 3D model of the diseased kidney. As the scan is personalised for each patient, this meant that the surgeons were able to construct a 3D scale model of each individual’s kidney cancer.

The model – which was printed using two different materials – allowed the surgeons to accurately determine the margins of the kidney tumours. The 3D-printed organ model was made of transparent material so that the blood vessels could be seen from the outside, meaning that surgeons could see the exact position of the blood vessels prior to surgery. This allowed the surgeons to simulate surgery on the kidney tumour prior to real surgery. The surgery itself was then performed robotically.

Presenting the work at the European Association of Urology (EAU) Congress in Stockholm (11-15 April, 2014), lead researcher Dr Yoshiyuki Shiga said: “The use of this ‘hands-on’ model system gave us a 3D anatomical understanding of the kidney and the tumour. This enabled the surgeon to work on a smaller area.

This is important, as it means that the area where the blood supply is interrupted during surgery can be reduced, in fact we found that the shortest interruption time [ischaemic time] was only 8 minutes, compared to a normal average of 22 minutes. We also found that where we had to remove part of the kidney, the fact that we knew the exact location of the blood vessels helped us greatly.

“At the moment this is still an expensive technique, adding between $500 and $1500 to the cost of surgery, but we hope that if it is more widely used then costs will fall.”

Commenting for the EAU, Professor Joan Palou (Barcelona, Director of the European School of Urology), said: “It looks interesting as a new methodology to improve and facilitate to learn robotic surgery. It shows great potential, especially in the most difficult cases. Any surgery benefits from the surgeon being experienced and knowing what to expect, and at this point this seems to be the best simulation we have.

“The learning process has been a matter of debate, and with the introduction of new technologies during the last few years, training has become an important issue. This is why the EAU has created the European School of Urology training group, to order to promote, stimulate and standardize the learning process. If it is developed appropriately, this new 3D process may feed into our training programme”.

The researchers write of the results in their paper – “Benefit of three-dimensional printing in robotic laparoscopic renal surgery: Tangible surgical navigation using a patient-based three-dimensional printed kidney” – In our experience with ten consecutive cases of navigation surgery, the surgical margin and renal function were successfully secured. The median operative time was 145 min, and the shortest ischemic time was 8 min. This system enables simulation of the preoperative and intraoperative situations. Initial practice on a tangible surgical navigation using a patient-based 3D printed kidney is an advantage that can be shared with the operating room staff as well as the surgeons, as it enables them to obtain an in-depth understanding of the range of resection, angle, depth, and suturing type that will be needed in the surgery.

The use of our navigation system was helpful for gaining a 3D anatomical understanding of the surgical target, since it enabled the surgeon to reduce the ischemic area by performing segmental artery clamping. In a partial nephrectomy, in particular, the use of this tangible model increases the surgeons’ understanding of the vascular structure. The ischemic time was shortened compared to that of conventional surgery. We could perform preoperative planned procedures in all cases and prevented needless renal hilar clamping or radical nephrectomy. However, creating these organ models can cost ¥50,000 ($500) to ¥150,000 ($1500). As the need and use of this technology increases, the cost of the organ model will decrease.

They conclude: This patient-based 3Dprinted organ model provides tangible surgical navigation. Replicas of patients’ organs provide important orientation for robotic assisted partial nephrectomy and enable precise clamping of the segmented arteries. The combined use of our interactive navigation system and these replicated organs leads to satisfactory surgical outcomes.

Tissue testing during breast cancer lumpectomies prevents need for reoperation

Unique laboratory testing during breast cancer lumpectomies to make sure surgeons remove all cancerous tissue spares patients the need for a repeat lumpectomy in roughly 96% of cases at Mayo Clinic in Rochester, a success rate much higher than the rate than national rates in the United States, a Mayo study shows. During the years reviewed, 13.2% of breast cancer lumpectomy patients nationally had to return to the operating room within a month of their initial surgery, compared to 3.6% at Mayo in Rochester, which uses a technique called frozen section analysis to test excised tissue for cancer while patient are still on the operating table.

The findings are published in the journal Surgery.

Frozen section analysis was pioneered at Mayo Clinic more than 100 years ago and is used in a variety of Mayo surgeries.

In breast cancer lumpectomies, surgeons remove tumours with a small amount of normal tissue around them to help ensure they excised all of the cancer. This is known as obtaining “clean” or “negative” margins. During surgery at Mayo in Rochester, that tissue is transferred from the operating room to a nearby pathology lab, where the edges around the lumpectomy are shaved and each sample is frozen and reviewed under a microscope by a pathologist, all within minutes, while the patient is still anesthetized. The pathologist immediately gives the surgeon the results, so the surgeon knows whether the lumpectomy is complete or there is still cancerous tissue to remove, and at which margin, before the operation concludes.

Mayo Clinic remains one of the only U.S. medical centres to perform frozen section analysis, and its process is unique, including use of a Mayo-modified microtome to freeze tissue so the pathologist can get a 360-degree view around the lumpectomy cavity.

“This intense pathological evaluation with the use of frozen section of the margins while the patient is asleep really drops down the re-excision rate,” says first author Judy Boughey, M.D., a breast surgeon in the Mayo Clinic Cancer Center. “Achieving negative margins in one operation has a huge impact on the patient’s satisfaction, decreases time away from work, time traveling back and forth to hospital appointments, and the financial cost to the patient, the insurance company and the hospital for a second operation.”

Mayo researchers compared 30-day reoperation rates for breast cancer lumpectomy patients at Mayo Clinic in Rochester with the reoperation rates for such patients at hospitals nationally as reported in American College of Surgeons National Surgical Quality Improvement Program data from 2006-10. Patients in the national data were roughly four times likelier to undergo reoperation as those at Mayo in Rochester. Unlike mastectomy a breast cancer lumpectomy typically preserves enough breast tissue to achieve an acceptable cosmetic result. Most women diagnosed with breast cancer have a choice between a lumpectomy and a mastectomy. However, women who have a lumpectomy and later learn another operation is needed to obtain negative margins may decide to get a mastectomy at that point, Dr Boughey says.

The study’s senior author is Elizabeth Habermann, Ph.D., associate scientific director of the Surgical Outcomes Program in the Mayo Clinic Kern Center for the Science of Health Care Delivery. Mayo Clinic funded the research.

 Date of upload: 12th May 2014

 

                                  
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