Trudging from place to place with heavy weights on our backs is an everyday
reality for many people – from schoolchildren toting textbooks in backpacks to
firefighters and soldiers carrying equipment they require in their work. Muscle
and skeletal damage are very real concerns.
Now Tel Aviv University
researchers say that nerve damage, specifically to the nerves that travel
through the neck and shoulders to animate our hands and fingers, is also a
Prof. Amit Gefen of TAU’s biomedical engineering department
and Prof. Yoram Epstein of the university’s Sackler Faculty of Medicine, along
with PhD student Amir Hadid and Dr. Nogah Shabshin of Assuta Medical Center,
have determined that the pressure of heavy loads carried on the back has the
potential to damage the soft tissues of the shoulder, causing microstructural
damage to the nerves.
The result could be anything from simple irritation
to diminished nerve capacity, ultimately limiting the muscles’ ability to
respond to the brain’s signals, inhibiting movement of the hand and the
dexterity of the fingers. In practice, this could impact functionality, reducing
a worker’s ability to operate machinery, compromising a soldiers’ shooting
response time or limiting a child’s writing or drawing capacity. The research
was published in the Journal of Applied Physiology.
Focusing their study
on combat units in which soldiers must carry heavy backpacks, the researchers
discovered that, in addition to complaining of discomfort or pain in their
shoulders, soldiers also reported tickling sensations or numbness in the
Exploring this issue in a noninvasive manner, they used
biomechanical analysis methods originally developed for investigating chronic
wounds. The analyses show how mechanical loads, defined as the amount of force
or deformation placed on a particular area of the body, were transferred beneath
the skin to cause damage to tissue and internal organs.
Based on data
collected by MRI scans, Gefen and Epstein developed anatomical computer models
of the shoulders. These showed how pressure generated by the weight of a
backpack load is distributed beneath the skin and transferred to the brachial
plexus nerves. The models also account for mechanical properties, such as the
stiffness of shoulder tissues and the location of blood vessels and nerves in
the sensitive areas which are prone to damage.
loading was also seen to have a high physiological impact.
load applies tension to these nerves,” explained Gefen. He noted that the
resulting damage “leads to a reduction in the conduction velocity – that is, the
speed by which electrical signals are transferred through the nerves.” With a
delay or reduction in the amplitude or intensity of signals, nerve communication
cannot properly function, he said.
These results apply to people from all
walks of life, said Gefen.
Many professions and leisure activities, such
as hiking or traveling, involve carrying heavy equipment on the back. The
researchers plan to extend this study in two directions – to study the effects
of loading on nerve conductivity and to examine the impact of these heavy loads
on children’s bodies.
School bags are a major concern, he warned. It
cannot be assumed that children’s bodies react to shoulder stress in exactly the
same way as adults. Differences in physiology could lead to different
consequences, tolerance and damage levels.LEARNING FROM MASS
In the ongoing effort to achieve optimal preparedness for
disasters, the conducting of a structured “after-action review” process is of
utmost importance. A recent article in the American Journal of Emergency
Medicine describes the process of scientifically developing a structured tool
for such a process in emergency departments following a mass casualty
This process was led by Ben- Gurion University of the Negev’s
Dr. Bruria Adini, an emergency medicine expert and author of several other
validated tools that assess preparedness. The current study was conducted by
masters students in emergency medicine.
The students, who are also senior
staff in various level 1 hospitals, chose this topic for research as they had
personally experienced the need for such a tool.
Bringing in their
personal knowledge, they conducted an extensive literature review among experts
and finally tested the tool during a simulated earthquake drill. The study was
successful in producing a practical tool that has already been approved and
adopted by the Health Ministry’s emergency and disaster management division. The
tool includes specific guidelines regarding when and how to use it.
Limor Aharonson-Daniel, chairman of the Beersheba university’s emergency
medicine department and the PREPARED Center for Emergency Response Research,
said this study is a great example of the fruitful collaboration between
academia and the field, a partnership that was recently formalized in an
agreement between BGU and the ministry. She was very pleased that the students –
Tami Greenberg, Fabiana Eden, Tami Chen and Tali Ankri – managed to introduce an
important change during their studies.
The significance of the tool goes
beyond the immediate assessment as it not only facilitates learning lessons
regarding emergency response, it also enables ventilation of feelings, thus
mitigating anxieties and expediting a speedy return to normalcy.
publication of this study in this prestigious journal may be a vehicle for
international application of the findings of this study in other healthcare
systems,” says Adini.GOING UNDER
The Royal College of Anesthetists and
the Association of Anesthetists of Great Britain and Ireland have published in
the journal Anesthesiaa
initial findings on how many surgical patients
experienced accidental awareness during general anesthesia.
asked senior anesthetists in UK hospitals to report how many cases of accidental
awareness during general anesthesia they encountered in 2011.
million general anesthetics are administered in UK hospitals each
Although previous reports claimed to have found a surprisingly high
incidence of awareness, about one in 500 general anesthetics, the new report
found it to be much less common in the UK. The researches found only one episode
out of every 15,000 patients put under general anesthesia.
University Prof. Jaideep Pandit commented, “Anesthesia is a medical specialty
very much focused on safety and patient experience. We identified accidental
awareness during anesthesia as something that concerns patients and the
profession.... We are particularly interested in patient experiences of
Although we know that some patients do suffer distress after
these episodes, our survey has found that the vast majority of episodes are
brief and do not cause pain or distress.”
University of Bath Prof. Tim
Cook added: “Risks to patients undergoing general anaesthesia are very small and
have decreased considerably in the last decades....While our findings
are generally reassuring for patients and doctors alike, we recognize that there
is still more work to be done.”