Tag: 14/6/23

Categories : Surgeries & ProceduresTags : Leave a comment

Study Unravels the Mechanics of the Ideal Surgical Knot

On By ModernMedia
Surgical knot tied on a rigid support. Credit: Alain Herzog / EPFL

Surgeons knot sutures intuitively. While simple square and granny sliding knots are often used in surgery, it takes years to master them so that they stay in place without loosening or breaking. Much mathematical research has been done on knot topology and geometry, but little is known about the physics of knot mechanics, like the material properties of knotted filaments. Now, in Science Advances, researchers have published the first physics-based study on the mechanics of surgical knots, and exactly what properties influence their strength.

“It’s astonishing to think how much we rely on knots, when we don’t really understand how they work,” says Pedro Reis, head of the Flexible Structures Lab in the School of Engineering (Institute of Mechanical Engineering). Reis and PhD student Paul Johanns teamed up with Lausanne-based plastic surgeon Samia Guerid to lead the study.

“Understanding surgical knot mechanics can raise awareness among experienced surgeons, be incorporated into training programs, and advance robotic surgery by enabling more effective knot-tying capabilities,” says Guerid. “Such knowledge could also influence the development of suture materials that enhance slippage resistance in sliding knots.”

The power of plasticity

Reis, an avid climber, has a personal interest in secure knots and has conducted several previous studies on knot mechanics. He explains that many knots can be described as free-ended structures that provide a holding force, with their functionality dictated by the variables of topology, geometry, elasticity, contact, and friction. But for the study of surgical knots, Reis and his colleagues considered a key sixth factor: polymer plasticity of the suturing filament.

The strength of sutures made from polypropylene filaments used in surgery depends on the tension applied during the tying of the knot (pretension). This pretension permanently deforms, or stretches the filament, creating a holding force. Too little pretension causes the knot to come undone; too much snaps the filament.

The team analyzed 50-100 knots tied by Guerid, and found that the surgeon was able, thanks to her years of experience, to intuitively target the pretension ‘sweet spot’. Using precision experiments, X-ray micro-computed tomography, and computer simulations, the scientists defined a threshold between ‘loose’ and ‘tight’ knots, and uncovered relationships between knot strength and pretension, friction, and number of throws.

“Surprisingly, despite the complex interplay between all six factors, we observed a simple, robust emergent behavior vis-à-vis knot strength. But we still don’t have a predictive model to fully explain the relationship between knot pretension and strength, which seems to be consistent, even outside surgical knots. We’re already looking into this question.”

A training tool for surgeons…and robots

The team’s findings could be a valuable tool for training surgeons, as they could allow the parameters of a secure knot to be translated into practical guidelines. While experience would remain important, the idea is that safe knot-tying could be taught using predictive models, rather than intuition gained only through years of practice.

“Our data gives us a recipe for determining the ideal pretension and number of throws, for example, depending on the type of filament used,” Reis says

“The lack of physics-based analysis has been a limitation,” Guerid adds. “Quantifiable data on knot mechanics could be integrated into training programs to assess the tensile strength of each knot, ensuring trainees acquire necessary skills for successful surgeries. The data could also facilitate development of robotic surgery via the programming of robotic systems.”

Source: EurekAlert!

Categories : Healthcare Politics and Regulations Medical IndustryTags : 4 Comments

‘No Need to Panic’ Over NHI, Says Discovery CEO

On By ModernMedia
Photo by Hush Naidoo on Unsplash

On Tuesday, June 13, South Africa’s National Assembly approved the National Health Insurance (NHI) Bill, signing this new law into effect in the face of strong expert objections. The CEO of Discovery Health, Dr Ryan Noach, said that at the moment there is “no need to panic” over NHI, although overwhelming negativity was a major concern. . This was reflected in Quicknews polls results, with 98% of respondents expressing skepticism over NHI implementation.

Speaking in an interview with Newzroom Afrika, he responded to comments that the implementation of the NHI would devastate the private healthcare sector, which he said “sounds like a panicky reaction”.

While he did not say that NHI implementation would be without consequences, the chief executive of the country’s largest private medical scheme reminded viewers that, even with NHI as promulgated now, there was still a long way to go before there was any impact on private healthcare schemes or systems.

Health Minister Dr Joe Phaahla hailed the Bill: “This is one of the most revolutionary pieces of legislation presented to this house since the dawn of our democracy in 1994.” Briefing the media, he was bullish on existing issues of corruption and mis management in healthcare, saying “Those issues must be dealt with.” He pointed to a number of “good examples” of institutions.

But serious questions about the impact, implementation and feasibility of the extraordinarily expensive and far-reaching Bill have yet to be answered.

The impact of Section 33

Dr Noach noted that one important point regarding the Bill is Section 33, which “talks about the full implementation of NHI before any impact on medical schemes.” Essentially, the NHI would have to be fully in place before the healthcare and health insurance sectors would be affected.

He added that the Department of Health’s expected that NHI would take some 10 to 15 years to fully implement after its promulgation. Speaking with the experience of a scheme that provides for 4 million people, he said that it is already a huge amount of work, and the task of catering to the entire population of South Africa would be even greater.

Dr Noach notes that as for the necessary financing bill for the NHI, it is nowhere to be seen. Little said about it by the Treasury, which has only noted that it is “nascent”. As the population contributes GDP of 8.5% to healthcare, the assumption seems to be that this 8.5% would simply be redirected into a NHI scheme, which is not likely to happen.

Medical funds are contributed from medical schemes after tax, are well-protected by schemes, and as trust funds they essentially belong to the members. By law no-one can take away access to those funds: it would be like taking away people’s pension funds.

No parallel with any other country’s public health scheme

This singular NHI fund would essentially be a monopoly, and there were also no other examples of this to be found anywhere in the world. Even with the UK’s NHS, 12% of the population opts for private medical insurance. No other countries exclude by law the participation of private insurance and private funders. The annual spend would be R500bn to R700bn, and the NHI would disburse this to about 100 000 healthcare providers – assuming that the healthcare market would remain in its present form, which would likely suffer.

The biggest short term risk of the Bill would be the emigration of skilled healthcare professionals from a very negative sentiment emerging among in that grouping.

Meanwhile, those working in the public sector are battling under corruption and a lack resources while those in the private sector are extremely concerned. According to a Quicknews poll which ran for the month of June, 97.78% of the 90 respondents agreed with the South African Medical Association’s objections to the Bill.

In early 2022, a Quicknews poll had found that 81% of respondents had either considered emigrating due to the NHI Bill or were actively planning to do so.

Dr Noach says that “we are doing everything we can to calm the health professionals, partner them and work with them and reassure them, because we do believe that the outcome here could be optimistic.” A version of NHI would be welcomed.

As for the eventual fate of medical aid scheme under Section 33, once the Minister determines that NHI is fully implemented (and it is unclear how that would be determined), only those services not covered by NHI would be covered by medical aid schemes – though there is no indication at this stage of what would be covered.

An alternative approach to NHI

Before this can even be implemented, the government needs to find R200 billion to fix the public healthcare system, something which Dr Noach applauds as a priority.

He described an alternative NHI, with policy reform one in both private and public healthcare to create a “multi-funded environment”, something which Discovery’s actuarial work had found to be a better fiscal option. The NHI has many favourable qualities, which are smart and feasible, he continued.

The current monopolistic approach to NHI would create a single pot of money which would be the largest fund in the country by far – with its attendant risks.

Notes: Updated to reflect latest Quicknews poll results and to include Dr Joe Phaahla’s comments on the Bill.

Categories : Mental Health Obstetrics & GynaecologyTags : Leave a comment

New Study Finds Depression Risk with Hormonal Contraceptive Use

On By ModernMedia

The possibility that contraceptive pills might have negative effects on mental health and even lead to depression has long been debated. Now, evidence published in Epidemiology and Psychiatric Sciences shows that contraceptive pills are in fact linked to depression, with teenage girls at particularly increased risk.

This study is one of the largest and widest-ranging to date, following more than a quarter of a million women from UK Biobank from birth to menopause.

The researchers collected data about women’s use of contraceptive pills, the time at which they were first diagnosed with depression and when they first experienced symptoms of depression without receiving a diagnosis. The method of contraception studied was combined contraceptive pills, which contain progestogen and oestrogen. Progestogen prevents ovulation and thickens the cervical mucus to prevent sperms from entering the uterus, while oestrogen thins the uterine lining to hinder the implantation of a fertilised egg.

“Although contraception has many advantages for women, both medical practitioners and patients should be informed about the side-effects identified in this and previous research,” says Therese Johansson at Uppsala University, one of the researchers leading the study.

According to the study, women who began to use contraceptive pills as teenagers had a 130% higher incidence of symptoms of depression, while the corresponding increase among adult users was 92%.

“The powerful influence of contraceptive pills on teenagers can be ascribed to the hormonal changes caused by puberty. As women in that age group have already experienced substantial hormonal changes, they can be more receptive not only to hormonal changes but also to other life experiences,” Johansson says.

The researchers were also able to see that the increased incidence of depression declined when the women continued to use contraceptive pills after the first two years. However, teenage users of contraceptive pills still had an increased incidence of depression even after stopping using the pill, which was not observed in adult users of contraceptive pills.

“It is important to emphasise that most women tolerate external hormones well, without experiencing negative effects on their mood, so combined contraceptive pills are an excellent option for many women. Contraceptive pills enable women to avoid unplanned pregnancies and they can also prevent illnesses that affect women, including ovarian cancer and uterine cancer. However, certain women may have an increased risk of depression after starting to use contraceptive pills.”

The findings of the study point to a need for healthcare professionals to be more aware of possible links between different systems in the body, such as depression and the use of contraceptive pills. The researchers conclude that it is important for care providers to inform women who are considering using contraceptive pills of the potential risk of depression as a side-effect of the medicine.

“Since we only investigated combined contraceptive pills in this study, we cannot draw conclusions about other contraceptive options, such as mini pills, contraceptive patches, hormonal spirals, vaginal rings or contraceptive rods. In a future study, we plan to examine different formulations and methods of administration. Our ambition in comparing different contraceptive methods is to give women even more information to help them take well-informed decisions about their contraceptive options,” Johansson says.

Source: Uppsala University

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Which IV Fluids to Use in Sepsis… and When Not to Use Them

On By ModernMedia
Photo by Marcelo Leal on Unsplash

In the leading Journal of the American Medical Association, two researchers outline how to use intravenous fluids to treat sepsis, a deadly condition that affects nearly a third of all ICU patients. Despite the fact that IV fluid therapy is a cornerstone of sepsis treatment, it’s not always a sure bet – in fact, as the authors outline in their paper, giving IV fluids can sometimes worsen sepsis.

Which fluids to give, how much to give and when have been fiercely debated for years.  

“This is an intervention that is cheap and easy to use and it can be life-saving, but it can also be harmful for patients if too much fluid is given,” explains first author Fernando Zampieri, a newly recruited assistant professor at University of Alberta.    

The new JAMA article sums up the latest science on the phases of sepsis and how much IV fluid to give at each stage of treatment. 

“It’s aimed at the clinician who works on the wards, who works in community hospitals, who works in emergency departments, explaining the mechanisms to assess whether patients are responding or not and decide whether more fluid needs to be given,” says Sean Bagshaw, professor and chair of critical care medicine, who co-wrote the paper with Zampieri and Matthew Semler of Vanderbilt University.

“These are really fundamental issues that have been challenging for clinicians to reconcile and have long been controversial, so this concise review bundles all recent evidence together,” Bagshaw says.

A complex and life-threatening condition

One in four patients who develop sepsis die from it, and it’s responsible for 11 million deaths per year, Zampieri estimates. Sepsis is an extreme response by the body to an infection, leading to a drop in blood pressure and thus a lack of oxygen circulation. Death occurs when oxygen-deprived organs such as the brain, kidneys or liver fail. 

Treatment almost always includes administering intravenous fluids, along with other interventions such as antibiotics and medications to boost blood pressure and oxygen delivery to tissues. The goal is to restore circulation without causing edema, or swelling, which can also be harmful to organs. 

Sepsis can occur at any time in life from infancy to old age, says Bagshaw. Zampieri points out that sepsis is not really one disease, but a complex condition with multiple causes. 

“When we talk about sepsis, you can be talking about things as different as a young woman with an infection after delivery all the way through to an elderly patient with a urinary tract infection. Those are two completely separate sources of infection, and the patient’s other conditions make treatment more complicated,” he says.

Zampieri says there are numerous clinical trials underway to refine sepsis treatment, but much is still unknown. Zampieri himself has been involved with trials in Brazil to determine whether slower fluids make a difference to clinical outcomes, to compare the efficacy of using saline versus a balanced solution (Plasma-Lyte 148), and to find out whether measuring lactic acid, which is produced when the body is starved of oxygen, is a good indicator of whether enough fluids have been given.

Digging for evidence to improve practice

Zampieri plans to continue his program of clinical trials and also wants to help physicians and health systems adopt best treatment practices as they are verified. Eventually he hopes to develop an accurate bedside test, such as using ultrasound, to better determine what level of fluids a patient requires.  

“Clinical trials are the best way to provide evidence that will change practice,” he says.

Bagshaw expects sepsis treatment to improve rapidly over the next decade thanks to such work.

“It took us 30 or 40 years to get to this point, and I think there’s still lots of questions to be answered about how best to individualise the resuscitation strategies amongst patients with life-threatening infection and sepsis,” Bagshaw says. “My hope is that Fernando will help catalyse some of those advances here at the U of A.”

Source: University of Alberta

Categories : Diseases, Syndromes and Conditions Injury & TraumaTags : Leave a comment

Autistic Adults Have Higher Risks of Injury and Disease

On By ModernMedia
Photo by Andrew Neel on Unsplash

A large-scale registry study found that older autistic adults have a significantly higher risk of injury, especially self-inflicted, and physical conditions such as type 2 diabetes, anaemia, heart failure and COPD. The findings were published in The Lancet Healthy Longevity.

“We found an increased disease burden in middle-aged and older autistic adults, both men and women, irrespective of the presence of intellectual disability,” says Shengxin Liu, doctoral student at Karolinska Institutet. “Our findings point up the need to improve the support and care of older autistic adults.”

In the population-based study, the KI researchers linked different national registers and compared the risk for five types of injury and 39 age-related physical conditions in people over the age of 45. Of the four million-plus people born between 1932 and 1967, 1930 women and 3361 men had an autism diagnosis. For each physical condition, they evaluated the 25-year cumulative incidence and the relative risk in autistic people compared with non-autistic people of the same sex and age.

Seven-fold risk of self-harm

Autistic people had a higher risk of four of five studied injures, for which self-harm accounted for the greatest risk increase, followed by poisoning, falls and other physical injuries.

“The risk of self-harm was worryingly high, a full seven times higher than in non-autistic people,” says Liu. “Reasons behind this remain largely unknown. One possible contributing factor could be mental health conditions that commonly co-occur with autism, such as anxiety and depression.”

The researchers also found a risk increase for 15 physical conditions. For example, autistic people had three times the risk of anaemia and glucose dysregulation and almost double the risk of heart failure, type 2 diabetes, and COPD (chronic obstructive pulmonary disease).

Multiple contributory factors

“We now need to find out the cause of these associations and how they are affected by factors such as biology, age when diagnosed with autism, psychotropic treatment and psychosocial environment,” says the study’s last author Mark Taylor, senior researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. “But most importantly, researchers, health services and policymakers need to cooperate to make sure that older autistic adults have a better quality of life.”

Since this was an observational study, no causal relationships can be ascertained, and the researchers were not able to take into account variables such as socioeconomic status. Furthermore, given that the study used Swedish registers, it is difficult to make generalisations to other countries.

Source: Karolinska Institutet