The economic cost of HIV/AIDS is far greater than previously estimated, and the cost is even higher for minorities, according to a new study that estimated the direct and indirect costs of the disease. The total lifetime cost of illness for Americans newly diagnosed with HIV in 2002 is approximately $36.4 billion, of which more than 80 percent is related to productivity losses, a cost that most previous studies have omitted. The study also reveals that while the direct costs of antiretroviral therapy may be high, these costs are eventually offset by extended productivity. The research shows that differences in medical care result in dissimilar costs — both direct and indirect — among different racial and ethnic groups.

The study is published on-line in the Journal of Acquired Immune Deficiency Syndromes (JAIDS), ahead of print publication. It is the result of collaboration among researchers at the Centers for Disease Control and Prevention (CDC), the Emory University Center for AIDS Research, and the Andrew Young School of Policy Studies at Georgia State University.

An estimated 40,000 people in the United States become infected with HIV each year. While researchers have previously estimated the economic costs of HIV/AIDS, they have focused primarily on the direct medical expenses of treating the disease. The results up to now have given an incomplete picture of the disease’s economic consequences, according to Angela Blair Hutchinson, PhD, MPH, a health economist at the CDC and lead author of the paper.

“We wanted to assess the economic burden of an HIV infection in the U.S.,” says Dr. Hutchinson, “by examining the impact of stage of disease at diagnosis and access to treatment on the cost of HIV infection and how this might differ by race/ethnicity.”

The research shows that differences in medical care result in dissimilar costs–both direct and indirect Ð for various racial/ethnic groups. “We found that direct costs were lower and productivity losses were higher for minorities,” says Dr. Hutchinson.

Specifically, minorities incur fewer direct medical costs than whites ($160,400 for blacks on average, compared with $180,900 for whites), but suffer greater financial damage from lost productivity ($838,000 for Hispanics and $766,800 for blacks on average, compared with $661,100 for whites).

The differences, according to Hutchinson, reflect disparities in treatment. Minorities are, on average, diagnosed at later stages of the disease than whites. In addition, whites with HIV/AIDS are more likely to receive antiretroviral therapy (ART).

As Dr. Hutchinson notes, “ART is not used universally because it is expensive. Many patients with HIV/AIDS do not have health insurance and/or do not have access to ART.”

Though ART is costly, it has proven very effective at extending lives, and productivity. The researchers found that ART patients have direct medical costs averaging $230,044, with a projected life expectancy of 24.4 years. Patients not receiving ART have direct medical costs of approximately $114,938, with a projected life expectancy of 12.4 years.

The additional years of productivity after being treated with ART mean that the more expensive treatment is actually more cost effective in the long run. “Universal access to treatment would be cost saving,” says Dr. Paul Farnham, a co-author and economist from the Andrew Young School of Policy Studies at Georgia State University, “because it decreases the years of life lost from the illness, and thus lowers productivity losses more than it increases the direct medical costs.”

Besides recommending such universal access, the paper also emphasizes the importance of diagnosing the disease early. As Dr. Hutchinson explains, in order to narrow the treatment divide and expense gap among racial/ethnic groups with HIV/AIDS, “There needs to be a focus on earlier diagnosis, particularly for minorities.”

Cardiologists know that treating depression likely will benefit patients complaining of cardiovascular problems, but lack the guidance to properly diagnose or recommend treatment for depression, according to a report out today from a National Heart, Lung and Blood Institute (NHLBI) Working Group, according to a report from a National Heart, Lung and Blood Institute (NHLBI) Working Group. The paper was published simultaneously in “Annals of Behavioral Medicine” and “Psychosomatic Medicine.”

According to the report, up to 20 percent of patients with heart disease meet the American Psychiatric Association’s criteria for major depression, and identifying better treatments for depression in this population could lead to improved medical, financial and psychosocial outcomes.

“One major aspect of the problem is that cardiologists don’t have a standard assessment to diagnose depression,” said Karina Davidson, Ph.D., chair of the NHLBI Working Group and co-director of the Behavioral Cardiovascular Health and Hypertension Center at Columbia University Medical Center. “It’s important that research in this area move forward so cardiologists can confidently address the issue of depression, knowing that their patients are getting the most appropriate and effective therapy.”

Dr. Davidson pointed out that antidepressant prescription use in heart attack patients is steadily rising, but in the absence of a large clinical trial that would clearly indicate the best way to treat depression in these cases.

There are a number of ways treating depression may impact cardiovascular health. Antidepressants may normalize platelet reactivity, which is implicated in leading to heart attacks. Also, depressed patients tend not to follow medical recommendations, so treating depression may influence them to take prescribed medications or follow other guidance from doctors.

Although depressed patients might be more likely to have cardiovascular risk factors such as increased weight and a sedentary lifestyle, many studies reviewed by the NHLBI Working Group controlled for those factors and still found a relationship between depression and cardiovascular health, meaning the link is independent of those risk factors.

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The NHLBI Working Group included an interdisciplinary team of cardiologists, psychiatrists, epidemiologists and clinical researchers from Columbia University Medical Center, Mount Sinai School of Medicine, University of Pittsburgh School of Medicine, Duke University Medical Center, University of Pennsylvania School of Medicine, University of California San Francisco, Harvard University, and many other major institutions.

Columbia University Medical Center provides international leadership in pre-clinical and clinical research, in medical and health sciences education, and in patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, nurses, dentists, and public health professionals at the College of Physicians & Surgeons, the College of Dental Medicine, the School of Nursing, the Mailman School of Public Health, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions.

Thyroidectomy (removal of the thyroid) has traditionally required multi-day hospitalization. At a minimum, many surgeons advocate overnight observation following this special surgical procedure. While the thyroid is a relatively superficial organ and mortality related are extremely low, its close proximity to other structures has inspired caution out of concern for possible complications, such as laryngeal nerve damage, hemorrhage, and trauma to the upper airway. Although the thyroidectomy can now be performed with minimally invasive approaches, short operative time, and without the need for surgical drains, physicians have continued to guard against complications with inpatient hospital stays.

Some surgeons have actively advocated moving the thyroidectomy from a primarily inpatient surgery toward an outpatient procedure. Despite their efforts, a consensus regarding optimal postoperative management of thyroidectomy patients has not been reached. A new study may shed some light on optimizing practices.

A new study examines a novel approach of careful patient selection coupled with prophylactic calcium supplementation to minimize hospital stays and enable same-day discharge. The authors of “Outpatient Thyroid Surgery is Safe and Desirable” are David J. Terris MD, Brent Moister, Melanie W. Seybt MD, and Christine G. Gourin MD, from the Department of Otolaryngology- Head and Neck Surgery, and Edward Chin MD, from the Department of Medicine (Section of Endocrinology), all at the Medical College of Georgia, Augusta, GA. Their findings are being presented at the 110th Annual Meeting & OTO EXPO of the American Academy of Otolaryngology-Head and Neck Surgery Foundation, being held September 17-20, 2006, at the Metro Toronto Convention Centre, Toronto, Canada.

Methodology

This prospective, non-randomized study of consecutive patients undergoing thyroidectomy between December 2004 and October 2005 was performed at the Medical College of Georgia Health System and Augusta Veterans Administration Hospital. Patients were segregated into two groups on the basis of admission status (outpatient or inpatient). Patients undergoing 23-hour observation with an overnight stay were considered inpatients, while outpatients were discharged directly from the ambulatory recovery unit. Demographic and clinical data were collected; outcome data were compiled including estimated blood loss (EBL), duration of surgery (time from skin incision to closure), time to discharge (time from skin closure to hospital discharge), need for admission, and hospital charges. Hospital charges were queried to include total billed charges over the dates of service related to thyroidectomy.

A number of surgical techniques were used, including a Kocher incision, minimally invasive thyroid surgery with access to the thyroid compartment, and endoscopic thyroidectomy. Laryngeal nerve monitoring was employed as required. Vocal cord mobility was assessed and documented preoperatively and again in the post-anesthesia care unit or on the ward using flexible fiberoptic laryngoscopy. Following surgery, outpatients were assessed and discharged once ambulatory, tolerating a diet, and managing their pain with oral medications. Patients were seen for follow-up within one to two weeks after surgery and subsequently as clinically indicated.

All patients who underwent total or completion thyroidectomy were placed on a prophylactic calcium supplementation regimen consisting of a three-week taper of oral calcium carbonate (600mg TID for the first week, 600mg BID for the second week, and 600mg Qday for the third week). Postoperative ionized calcium levels were measured following convalescence to determine the presence of permanent hypocalcemia. Inpatient stays were for medically infirm patients with significant co-existing conditions, patients who underwent concomitant procedures requiring admission, and patients who expressed a preference for admission. Patients with large lesions incurring a potential for significant postoperative dead space were not considered suitable for outpatient management. All other patients were considered for management on an outpatient basis.

Results

Ninety-one patients underwent thyroid surgery. Fifteen patients were male, seventy-six patients were female; the mean age was 46.3 ± 14.7 years. Fifty-two (57 percent) were managed on an outpatient basis. Thirty-nine were considered inpatients (twenty-six of these remained in the hospital overnight for a 23-hour observation period; 13 were admitted for a mean of 3.4 ± 2.8 days). The mean age of the outpatients (44.8 ± 13.3 years) was not statistically different from the mean age of the inpatients (48.5 ± 16.3 years). The gender ratio was also similar (85 percent female among outpatient, 82 percent female among inpatients).

Outpatient Thyroid Surgery is Safe and Desirable

Fifty-two patients had a thryroid procedure performed on an outpatient basis, 26 patients were observed under a 23-hour status, and 13 were admitted. There were two complications in the outpatient group and one in the inpatient group. Costs were significantly lower for outpatients ($7,814) than for inpatients ($10,288. The procedures consisted of 42 hemithyroidectomies (surgical removal of one lobe of the thyroid gland), 38 total thyroidectomies, and 11 completion thyroidectomies. Operative time was lower in the outpatient group (102 ± 32 vs. 144 ± 51 minutes).

Despite the trend toward outpatient surgery, surgeons who perform thyroid and parathyroid surgery have been reluctant to adopt this approach primarily out of concern for bleeding and transient hypocalcemia. However, the advent of new ultrasonic technology, used in this study, has improved the ability to achieve and maintain a bloodless field. This technology has led to a conclusion by many that surgical drains, a soft plastic tube that drains fluid out and sources of infection of the area, offer no benefit to the patient, and if anything, result in a higher rate of infection and bleeding.

A second major deterrent to performing thyroid (and parathyroid) surgery on an ambulatory basis is the fear of life-threatening hypocalcemia, or low blood calcium level. Ten years ago, researchers described a regimen of oral calcium administration following parathyroidectomy, supporting outpatient status in nearly all cases performed at a major hospital. Researchers for this current study provided oral calcium supplementation in patients undergoing total or completion thyroidectomy to accomplish outpatient thyroid surgery safely. This method has proven uniformly successful with the study subjects, with none displaying any signs of calcium deficiency in the blood.

Conclusions

Despite cost-savings achieved with outpatient surgery, the real benefits of pursuing ambulatory thyroidectomy were not financial. The peripheral benefits of outpatient surgery include the advantages of convalescence in the home environment (which is appealing to many individuals) and minimizing exposure to the organisms which populate most medical centers. On the other hand, patients for whom inpatient hospitalization should still be considered include medically infirm individuals, those undergoing concomitant procedures that would normally require admission, or those with known blood disease.

This study suggests that for carefully selected patients who prefer convalescence at home, and are not weak due to age and disease, outpatient thyroid surgery is safe and cost-effective, even when a total or completion thyroidectomy has been performed.

Two-thirds of women who quit smoking during pregnancy want to avoid cigarettes after delivery, but concern about weight may interfere, according to a new study.

“A woman’s feeling about her ability to control her weight affected her motivation to smoke,” said lead author Michele Levine, Ph.D., at the University of Pittsburgh Medical Center. This association went “above and beyond” factors including a woman’s level of dependence on nicotine, whether she had a partner who smoked and whether she planned to breastfeed her baby.

Levine and her colleagues conducted the study to understand why so many women resume prior smoking habits after pregnancy. Levine said that although there’s a lot of research on helping women to quit during pregnancy, “something happens after the baby is born that leads women to go back to smoking.”

The authors interviewed 119 pregnant women who smoked at least eight cigarettes a day before pregnancy but quit once they became pregnant. During the third trimester, the women responded to the question, “How motivated do you feel to stay quit after your baby is born?” Based on their responses, researchers divided the women into two groups: those highly motivated and those less motivated to remain smoke-free after birth.

The women were also asked if they felt confident about their ability to avoid cigarettes after giving birth and if they thought they could manage their weight after quitting smoking.

Study questions also addressed symptoms of stress and depression, since mood may affect a woman’s desire to abstain from smoking.

Sixty-five percent of women in the study - published in the October issue of the Annals of Behavioral Medicine - reported feeling highly motivated to steer clear of cigarettes after delivery and 74 percent expressed confidence in their ability to do so, a finding supported by previous research. Not surprisingly, the authors said, women who felt highly motivated to avoid smoking also tended to feel confident that they could do so.

What surprised the authors was the link between weight concerns and desire to remain abstinent. Compared to less-motivated women, “Motivated women were more likely to say they could control their weight without smoking and less likely to say they used smoking to control their weight,” Levine said. Women motivated to remain smoke-free during the postpartum period were also more likely to say they would breastfeed their infants.

Elyse Park, Ph.D., a psychologist in Boston not involved with the study, said the results deal only with what women intend to do after delivery - not their actual behavior. “Most women who are smoking want to quit during pregnancy, but the reality is that very few of them are able to do so. Even in women who are successful, very few are able to maintain quitting,” she said.

Because weight concerns are such a prevalent problem for American women, finding ways to address concerns about eating and weight may help prevent postpartum smoking relapse, the authors suggested.

Park suggests that pregnant women who want to remain smoke-free find a behavioral program - whether that’s quitting cold turkey or taking a stepwise approach to cutting back on cigarettes - that fits them. “There’s a lot of stigma against smoking during pregnancy; a lot of women genuinely want to quit but they’re struggling to do so,” she said.

This research was supported by a grant from the National Institute on Drug Abuse.

Cancerbackup, the cancer information and support charity, has launched what it hopes will be the biggest ever survey of people affected by cancer. The aim is to increase understanding of how the provision of the right information, to the right people, at the right time helps them make the right choices about their treatment and care.

“Information for people affected by cancer has long been recognised as vital”, says Derryn Borley, Head of Cancer Services, Cancerbackup. “Therefore Cancerbackup is undertaking this study to find out ways in which having clear and trustworthy information about cancer can affect people’s lives, from the first visit to the GP through all stages of treatment and care.”

By knowing how and when people would like to receive the information, and what best serves their needs, Cancerbackup will aim to shape its service and influence healthcare providers to deliver relevant information in the most useful way.

Today, leading organizations from across the healthcare spectrum joined together to ensure that the United States is prepared to deliver on a major women’s health breakthrough - the elimination of most forms of cervical cancer through access to new vaccines and screening. The Partnership to End Cervical Cancer’s goal is to ensure the immediate inclusion of cervical cancer vaccines as part of routine preventive healthcare for American women. Cervical cancer, caused by persistent infection with oncogenic human papillomavirus (HPV), is the second most prevalent cancer among women today, taking the lives of more than 270,000 women worldwide every year.

“This Partnership is inspired by the enormous opportunity a vaccination will offer to help eliminate most forms of cervical cancer, but we are concerned that the public health landscape is not primed to ensure broad access to vaccines,” said Phyllis Greenberger, M.S.W., president and chief executive officer of the Society for Women’s Health Research and chair of the Partnership to End Cervical Cancer. “Our goal is to educate women about cervical cancer and to encourage the public health network, physicians and policymakers to take action to ensure that women have access to medical breakthroughs, such as new vaccines.”

The more than 20 member organizations of the Partnership have formed four key committees to address the major policy and public health challenges to ensuring access to vaccines for women.

– The Cervical Cancer and HPV Education Committee will increase awareness among women of the human papillomavirus (HPV) as the necessary cause of cervical cancer and the benefits of vaccination in women. — The Access/Coverage for Vaccines Committee will educate policymakers on the value of universal access to these vaccines and the requisite coverage of the cost.

– The Medical Home Committee for Adult Women Vaccination will develop and implement recommendations to inform medical practice guidelines that include routine screening and vaccination.

– The Health Disparities Committee will strive to ensure that women in communities with higher incidence and mortality rates of cervical cancer have equal opportunities to receive the vaccines.

“All women are at risk for cervical cancer. From a women’s health perspective, a cervical cancer vaccine is as revolutionary as the birth control pill,” said Stanley Gall, M.D., American College of Obstetricians and Gynecologists’ (ACOG’s) representative to the Advisory Committee on Immunization Practices; professor of Obstetrics, Gynecology and Women’s Health, and Public Health and Information Science, University of Louisville; and Steering Committee member and chair, Medical Home for Adult Women Vaccination Committee, Partnership to End Cervical Cancer. “That we can potentially eliminate most forms of a cancer through a series of vaccinations is a significant milestone in healthcare history.”

Said Ciro de Quadros, M.D., M.P.H., president and chief executive officer of the Sabin Vaccine Institute and Partnership Steering Committee member, “Comprehensive vaccination programs work - as we’ve seen with the significant reduction or elimination of smallpox worldwide and measles in the Western Hemisphere. Today, the Partnership is making the commitment to play a leadership role in the campaign to end as much of cervical cancer as can be prevented with these vaccines and screening in this country.”

Partnership member organizations:

American College Health Association
American College of Obstetricians and Gynecologists
American Medical Women’s Association
American Social Health Association
Association of Women’s Health, Obstetric and Neonatal Nurses
The Balm In Gilead, Inc.
Cancer Research and Prevention Foundation
Coalition of Labor Union Women
Digene Corporation
GlaxoSmithKline
National Association of County and City Health Officials
National Association of Nurse Practitioners in Women’s Health
The National Black Nurses Association, Inc.
National Cervical Cancer Coalition
National Council of La Raza
National Family Planning and Reproductive Health Association
National Healthy Mothers, Healthy Babies Coalition
National Hispanic Medical Association
National Medical Association
Partnership for Prevention
Planned Parenthood Federation of America
Sabin Vaccine Institute
Marie Savard, M.D.
Society for Women’s Health Research

About cervical cancer:

Cervical cancer is caused by persistent infection with a common and contagious virus, HPV. HPV types 16, 18, 45 and 31 are responsible for 80 percent of all cervical cancers worldwide. Approximately 10,000 cases of cervical cancer will be diagnosed and nearly 4,000 women will die from it in the United States this year.

Cervical cancer deaths disproportionately occur in women of certain populations and geographic regions (e.g., African-American women in the South, Hispanic women along the Texas-Mexico border, white women in Appalachia, American Indians of the Northern Plains, Vietnamese American women, Alaska Natives) in the United States. Of the women in the United States who develop cervical cancer, about half have never had a Pap test and an additional 10 percent have not had a Pap in the last five years.

This issue, which has suddenly become headline news, has never been the subject of a full national debate in the profession, writes general practitioner, Richard Lehman.

Over the past 15 years there has been much talk of centralising services, and many local campaigns over individual threatened local hospitals, but little systematic collection of evidence to inform decision making, he says. Instead the process has been driven largely by financial pressures, by the European Working Time Directive and its effects on junior doctors’ staffing, and recommendations from the royal colleges.

Inevitably these pressures have driven hospitals to amalgamate services, at some cost to local accessibility. Equally inevitably such moves are deeply unpopular with patients, who may have to travel considerable distances for acute care that used to be on their doorstep.

The services most likely to be cut or merged throughout Britain are paediatrics, obstetrics, and emergency services - the very ones that patients particularly want to be near.

This presents a dilemma for trusts seeking to maintain a lower level of service, for example by substituting a midwife led birth unit for a consultant led obstetric service. Such units only accept “low risk” births, but emergencies inevitably occur, requiring transit to the nearest consultant led facility. If considerations of cost are allowed to predominate that may be a very long distance, he warns.

This issue is one of several that need to be debated urgently before a further wave of such changes sweeps the country, he writes. It cannot be timed or located to suit electoral convenience.

We need clearer guidance on issues such as safe transit times for paediatric and obstetric emergencies, and we need more creative thinking on shared site working and flexible training rotas.

It is time for GPs to reassert their role as patients’ advocates, defending the principle of local care for local people, he says. If doctors do not take an active role in questioning the present direction of policy then the public will rightly see us as more interested in our own career structures and hours of working than in providing a safe and accessible service.

The American Medical Student Association at American River College (AMSA ARC), part of nation’s largest, independent medical student organization, today announces the 2006 AMSA ARC Pre-Medical Conference, an annual event designed to educate and prepare California pre-medical students for entrance into medical school. This conference takes place in Sacramento, CA on the main campus of the American River College.

The theme of this year’s AMSA ARC Pre-Med Conference is “Your Passion in Action: Discover Your Path to Medicine,” and will take place Saturday, September 23 and Sunday, September 24. The conference is sponsored by the American Medical Student Association (AMSA) in conjunction with the Stanford Center of Excellence, and will feature informative speakers, workshops, and presentations to give attendees the opportunity to network with others, explore opportunities and learn tips and procedures for the medical school application process.

Keynote speakers of the conference are Dr. Charles Terrell, Vice President of the American Association of Medical Colleges (AAMC), David Carlisle, Director of California Office of Statewide Health Planning & Development, and Jay Bhatt, National President of the American Medical Student Association (AMSA). The conference will also exhibit discussion panels featuring Deans of Admissions from Harvard, Stanford, Duke, Cornell, University of Chicago, and many California schools including UC Davis, UC Irvine, UC San Diego, UCLA and UCSF.

The conference will showcase over forty-five workshops covering important topics such as paying for medical school, preparing for the MCAT, mock interviewing, M.D./PhD programs, and Women in Medicine. Program highlights include a medical school fair, community service fair, counselor/advisor round table, and an appearance by Steve Barkley, Director of the Medical College Admission Test.

“AMSA ARC is thrilled to be hosting this year’s AMSA Pre-Medical Conference,” says Joubin Afshar, AMSA ARC’s Premedical Regional Director. “It is a wonderful opportunity to bring together physicians-in-training from all over the state to increase their knowledge of the medical education process and all the amazing opportunities a career in medicine has to offer.”

Last year’s conference attendance of close to 1,000 students from over fifty-five colleges and universities from California established the AMSA ARC Pre-Medical Conference as the largest, most diverse gathering of premedical students in the nation.

“AMSA is proud to recognize and support its premedical members that will be the future of medicine,” says Jay Bhatt, National President. “I’m excited to participate in this incredible event that will highlight how to become involved in our wonderful profession as well as the many resources AMSA offers to support it.”

The American Diabetes Association (ADA) endorsed the Gestational Diabetes (GEDI) Act, which was introduced in the U.S. Senate today by Sens. Hillary Rodham Clinton and Susan Collins. The bill aims to lower the incidence of gestational diabetes and prevent women afflicted with this condition and their children from developing type 2 diabetes. Gestational diabetes develops in 4-8 percent of all pregnancies and affects about 135,000 women in the United States each year. Women who have had gestational diabetes or have given birth to a baby weighing more than 9 pounds are at a dramatically increased risk for developing type 2 diabetes later in life. Gestational diabetes is also associated with more health problems for both the mother and child during pregnancy and childbirth. The Gestational Diabetes Act will allow for better data collection in local communities and will expand the resources available to fight the disease.

“Diabetes has become a health epidemic that the federal government can no longer ignore,” said Lawrence T. Smith, Chair of the American Diabetes Association. “That is why it is vital to have approaches - like this one to address the growing incidence of gestational diabetes - that increase the government’s role in raising awareness and intensifying prevention efforts. We applaud Senators Clinton and Collins for their leadership on this legislation and urge the Senate to pass it quickly.”

The GEDI Act will set up a national grant program, which will enable communities to determine the most efficient and customized approaches to prevent, diagnose and treat gestational diabetes on the local level. Additionally, grants can be used by state-based diabetes prevention and control programs to collect and analyze surveillance data on women with and at risk for gestational diabetes, among other purposes. These components are crucial to stemming the tide of gestational diabetes in America, and lowering the overall incidence of diabetes in the United States.

Diabetes is one of the nation’s most prevalent, debilitating and costly diseases. Nearly 21 million American children and adults have diabetes, up from 18 million when the Centers for Disease Control and Prevention last measured diabetes prevalence in 2003. If present trends continue, one in three Americans, and one in two minorities, born in 2000 will develop diabetes in their lifetime. The cost of diabetes in the U.S. in 2002 was at least $132 billion.

The medical device currently used for intestinal research, the colonsope, causes patients great discomfort. At TU Delft, an alternative method has been developed, inspired by the way in which snails move. On September 18, researcher Dimitra Dodou received her PhD degree from TU Delft based on this research subject.

The intestines are an extremely difficult area to navigate through with a medical device. Yet, many people need to have intestinal examinations done to determine if, for example, they have intestinal cancer. The medical device currently used for this is the colonscope, a long, thin and flexible tube that causes patients great discomfort and pain. For this reason, researchers have been trying to develop alternative medical devices, such as, for example, a small robot that moves independently through the intestinal tract. There is a layer of slime, called mucus, on the inside of the large intestine (colon). The robots, as they move forward under their own power, ignore this layer of mucus and try, if possible, to suck or grab on to the intestinal wall, which results in the walls being stretched and the patient feeling pain and discomfort.

A better method, according to TU Delft researcher Dimitra Dodou, is in fact to use this layer of mucus and allow the robot to imitate the forward movement of a snail. A snail leaves a trail of slime behind it on the ground. This slimy material works simultaneously as a lubricant for gliding on and as a glue which the slug can grip hold of.

An intestinal robot should also have a similar layer to use. To achieve this, an adhesive layer is added to the mucus-like properties, which allows the device to be stuck to the layer of mucus. The ability to be attached to a surface covered with lubricant is a great technological challenge, because most adhesives normally only work on ‘clean’ surfaces. The researchers discovered a group of polymers, so-called muco-adhesives, that are suitable for this. Dodou used a pig’s intestine to evaluate how this material worked. Her findings revealed that muco-adhesives in the form of films provided by far the highest degree of friction.

Despite this, there is nevertheless no possibility of movement. A snail uses the exertions of pressure to change the characteristics of the middle layer, and thus lower the degree of friction, in order to move. In the intestine, however, pressure cannot be exerted, because this would cause the intestine to become deformed. The solution then is found in using smaller and larger surfaces that slide over each other. If a large surface coated with muco-adhesive remains still, and a relatively small surface coated with muco-adhesive begins moving in relation to the larger surface, the smaller surface has less freedom of movement. One by one the small ‘hands’ of the robot move forward. After this, the entire robot can be slide forward incrementally, whereupon the process of small surfaces shifting begins anew.

Additional experiments found that it is not only the size of the film surfaces, but also their shapes, which influence the degree of friction generated. It’s remarkable that the degree of friction increases when the surface size decreases, as a result of holes being made in the structure of the film. It is therefore possible to influence the degree of friction by creating holes in the muco-adhesive or indeed by closing the holes.

Moreover, by selecting different shapes, which owing to their compact size can achieve high degrees of friction, the device can be made smaller.

The researchers are currently building a prototype that will be tested in living pigs. We must however wait a while longer until a fully developed medical device is available.