Improving Knee Replacements: UC San Diego Health System first in nation to use device that boosts surgical precision and accuracy
Each year, approximately 600,000 total knee replacement procedures are performed in the United States, a number that is expected to rise exponentially in the next decade as the population ages. Successful surgeries require precise alignment in the knee, a challenging task made even more daunting by the expected rise in procedures. To help meet this demand, UC San Diego Health System is the first in the nation to use iASSIST, a computer navigation system with Bluetooth-like technology that improves surgical precision and accuracy in total knee replacements, decreasing the need for revision surgery.
The FDA-approved iASSIST device, designed by Zimmer Holdings, Inc., allows the surgeon to verify each surgical step, such as bone cuts and overall alignment, in real time, reducing mechanical errors during total knee replacements. The device is made up of small electronic pods, which are essentially mini-computers with wireless technology similar to smartphones. These electronic pods snap onto conventional instruments used in knee replacement surgery. By simply moving the knee in different positions during surgery, the device registers the anatomic axis of the leg unique to that patient, which guides each bone cut and ultimately places the knee implant in a more accurate alignment.
“This innovative technology allows us to deliver a more personalized knee to the patient and provide extreme accuracy in implant placement. Studies have shown that total knee replacement surgery has a higher failure rate when the knee is mal-aligned. This device enables orthopedic surgeons to restore a patient’s normal alignment with precision in a reproducible fashion, decreasing revision surgery and providing a more natural feel of the implant for the patient,” said Francis Gonzales, MD, with the Department of Orthopedic Surgery.
Current robotic and computer-assisted systems are less efficient and rely upon additional equipment, such as a large computer monitor in the operating room. The new device, about two inches wide, is the only piece of equipment needed to guide surgeons during a knee replacement. There are other patient-specific instruments available, said Gonzales, but the patient must undergo additional procedures, such as computed tomography (CT) scans or magnetic resonance imaging (MRI) prior to surgery.
“The iASSIST system allows us to bypass additional imaging and still get a patient-specific knee. This technology is quite intuitive and adds accuracy and precision to our instruments, giving us the ability to restore mechanical alignment with all patients regardless of their deformity,” said Gonzales.
Hans von Gersdorff was one of Germany’s most noted surgeons during the late 15th and early 16th centuries, though little is known about the personal life or background of the man. He is best remembered for his illustrated Feldbuch der Wundartzney or Fieldbook of Surgery.
Based largely upon the writings of famed medieval surgeon Guy de Chauliac, Gersdorff’s tome was widely used as a basic surgical text for many years, most notably for its advice on limb amputation, which Gersdorff was reputed to be much experienced, with at least 200 procedures.
Feldbuch contained numerous woodcut images of surgical procedures, such as trephining and bone setting, anatomical schematics and diseases or medical conditions, such as leprosy. The woodcuts were done by Johann Ulrich Wechtlin.
Many of the images created by Gersdorff and Wechtlin were quite technical, if not always complete or precisely accurate. The image above, known as “Wound Man,” is likely intended to be more evocative in nature – a quick guide to injuries that military surgeons might see on a battlefield.
Gersdorff died in 1529 at the age of 74, presumably the consequence of old age and not from one of the mortal afflictions above.
3,000th Lifesaving Heart & Lung Surgery at UC San Diego Health System
Lowest Mortality Worldwide, Most Patients Treated, Heart-Stopping Procedure
Surgeons at UC San Diego Health System have performed their 3,000th pulmonary thromboendarterectomy (PTE), a lifesaving surgery to clear the lung’s arteries of scar-like tissue that robs patients of their ability to breathe. During the extraordinary eight to ten hour surgery, the patient is put into a form of suspended animation in which the heart and blood circulation is completely stopped and the brain ceases activity while surgeons clear the pulmonary arteries of disease.
“Patients arrive at UC San Diego Sulpizio Cardiovascular Center from all over the world seeking this safe, highly specialized surgery. Some patients walk in unaided while others arrive by wheelchair or air ambulance,” said Nick Kim, MD, pulmonologist and director of pulmonary vascular medicine at UC San Diego Health System. “They all share a common burden: breathlessness. The clots cause chronic thromboembolic pulmonary hypertension, which not only leads to shortness of breath, but in most cases, progression to end-stage heart failure, and death, if not effectively treated.”
The surgery is a feat for the patient and the surgeon. In order for the clots to be removed, the surgeon must be able to see clearly into the lung’s tiny arteries. This requires operating without any blood present. To achieve this environment, the patient’s body is cooled and the blood is completely drained while the patient is on a heart-lung machine. The bypass machine is then stopped for 20 minutes while the surgeon races against the clock to remove the blockages. During this time, both heart and brain wave monitors are flat lined.
Using sophisticated techniques and special long, slender instruments, the surgeon rapidly dissects out the chronic clots without perforating the paper-thin artery wall. The clots look like white scar tissue, which when arranged on a surgical table takes the shape of the intricate inner branches of the lung’s arteries.
Degenerative Scoliosis: a Q & A with neurosurgeon William Taylor
More than half of all adults over the age of 70 have degenerative scoliosis – a curving of the spine that may cause pain, numbness and postural changes that result in decreased height and the appearance of shrinking.
When conservative approaches like physical therapy, steroid injections or bracing do not produce satisfying results, surgery becomes a primary option. A new minimally invasive alternative called lateral lumbar interbody fusion permits certain patients to avoid the current, typical open surgery, and return to everyday activities more quickly.
Q: What causes curvature of the spine as we age?
A: Curvature of the spine may be caused by a number of factors, including fractures, congenital defects and even prior back surgery. In adults, scoliosis is usually related to degenerative disc disease, living longer and conditions such as osteoporosis and osteoarthritis. Everyone’s spine has a slight natural “S” curve, but with degenerative scoliosis, the spine is tilted more than 10 degrees in one direction. Sometimes patients may be teased about getting shorter in older age, but in reality this is a serious health condition that can cause pain and distressing neurological symptoms, such as numbness or tingling in the legs or difficulty taking deep breaths.
Q: How does the new surgical option differ from the current standard of care?
A: This new approach, which emerged about one year ago as part of a broader, on-going progression toward minimally invasive surgery, allows correction of up to 30 degrees per spinal segment in a minimally invasive procedure under general anesthesia. I’m able to make a 3-inch incision on a person’s side near their rib cage. I can then pass instruments through the incision to rebuild the defective portion of the spine with a small permanent implant. I like this approach because I can avoid all of the major organs and structures, such as muscles and ligaments.
In contrast, the other option is a major surgery in which the spine is rebuilt with long incisions in both the front and the back of the patient’s body. With this approach, there is a greater likelihood of trauma, blood loss and complications.
Eligibility for either surgery depends on the severity of the scoliosis. Both are appropriate for different types of patients.
Q: Are there age constraints to these techniques?
A: Because lateral lumbar interbody fusion is designed to be less invasive, it is appropriate for patients of all ages. I have treated patients from the ages of 25 to 80. When the quality of the patient’s life has decreased or if curvature of the spine is so severe that it displaces the internal organs, causing cardiovascular or pulmonary dysfunction, it’s time to consider treatment.
Also in older adults, if the spine is curved so much that the person’s balance is unsettled, there may be an increased risk of falls and fractures. That presents other health risks. By using a less invasive approach, patients may experience decreased pain, a shorter hospital stay, and most important, a quicker return to what was once their normal way of life. Of course there are always risks involved with any surgery. These should be discussed at length with one’s doctor.
Nanoparticles of porous silicon, each 100 times smaller than a human hair, might be used as injectable microscopic reservoirs of therapeutic drugs. The surface of the particles can be coated with targeting molecules. Image courtesy of Chia-Chen Wu, UC San Diego.
DARPA, the U.S. Defense Advanced Research Projects Agency, has awarded $6 million to a multi-institutional team of researchers to develop nanotechnology therapies for the treatment of traumatic brain injury.
Led by Professor Michael J. Sailor, PhD, from the University of California San Diego, the project team seeks to use nanoparticles and similar approaches to deliver therapeutics to injured brains and reduce infections.
Ballistics injuries that penetrate the skull have amounted to 18 percent of battlefield wounds sustained by men and women who served in the campaigns in Iraq and Afghanistan, according to the most recent estimate from the Joint Theater Trauma Registry, a compilation of data collected during Operation Iraqi Freedom and Operation Enduring Freedom.
“A major contributor to the mortality associated with a penetrating brain injury is the elevated risk of intracranial infection,” said neurosurgeon Clark C. Chen, MD, PhD, of the UC San Diego Health System, noting that projectiles drive contaminated foreign materials into neural tissue.
Under normal conditions, the brain is protected from infection by a physiological system called the blood-brain barrier. “Unfortunately, those same natural defense mechanisms make it difficult to get antibiotics to the brain once an infection has taken hold,” said Chen. Watch a video and read the entire news release here.
Ithaar Derweesh, MD, urologic oncologist, UC San Diego Moores Cancer Center.
Kidney Sparing Surgery Underutilized for Patients Who Need It Most
Researchers at the University of California, San Diego School of Medicine have released study results that show national treatment trends in the surgical management of patients with kidney disease. The study found that partial and complete kidney removal (total nephrectomy) and energy-based techniques to destroy tumors are all on the rise. Surprisingly, the patients most in need of kidney-sparing surgery are still more likely to undergo total nephrectomy. The findings recently published online in BJU International.
“While the overall proportion of patients receiving kidney preserving treatments for localized kidney tumors continues to grow, the most significant, and perhaps unsettling finding was that patients with kidney insufficiency still undergo complete kidney removal – even though kidney preserving treatment may be indicated,” said senior author Ithaar Derweesh, MD, urologic oncologist at UC San Diego Moores Cancer Center.
The kidney is a vital organ which performs a variety of functions in addition to making urine. It controls blood pressure, bone health, and also makes a hormone to tell the bone marrow to produce red blood cells. Kidney insufficiency is characterized by a progressive decline in kidney function which may affect all of these actions.
“The study, which examined procedures over a 10-year period, found that patients with chronic kidney insufficiency had an almost two-fold higher probability of undergoing total nephrectomy than kidney preserving treatments, such as partial nephrectomy or tumor ablation,” said Derweesh, a pioneer in minimally invasive kidney surgery.
Derweesh added that further investigation is needed to confirm these findings, and to examine what factors are responsible for patient and physician selection of treatment for kidney cancer. He noted that in the case of small renal masses less than four centimeters in size, partial nephrectomy has equivalent outcomes to total nephrectomy, and that ablation techniques, such as cryoablation or radiofrequency ablation, and observation are valid options for select patients.