Islamabad, Sep 29 (Newswire): In the last 20 years, due to diagnostic and surgical advances, more and more patients have become appropriate candidates for spine surgery, and the number of these procedures performed has risen significantly.
While medical experts acknowledge the potential benefits of spine surgery, they also understand that complications can reduce the success in the short and long term.
"Complications following spine surgery may have a substantial impact on the quality of life of patients as well as the outcome of the primary surgical procedure," said orthopaedic surgeon Andrew J. Schoenfeld, MD, one of the authors of a new study recently published in the Journal of Bone and Joint Surgery (JBJS). This study identified several risk factors for a variety of complications and death shortly after spine surgery among men and women across the U.S.
Relatively few studies have explored the impact of factors such as comorbid medical conditions (simultaneously and usually independently existing health problems, including diabetes and cardiovascular conditions), age, body mass index (BMI), and gender on the risk of complications following spine surgery. Most research to date has focused exclusively on wound infection, and few studies have explored other possible complications and death.
"At the present time, the results of this study may represent some of the best available evidence regarding risk factors for complications and mortality following spine surgery," said Dr. Schoenfeld.
The study authors evaluated the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database for the years 2005 to 2008. This database documents preoperative information and postoperative complications and death among patients receiving surgery at participating medical facilities across the United States.
"One of the principle advantages of the NSQIP dataset is that it encompasses patients in selected hospitals from across the United States and includes a variety of spine surgical procedures," said Dr. Schoenfeld.
The study authors identified patients who received one or more spine operations. From 2005 to 2008, 3,475 spine-surgery patients were registered in the database.
They ranged in age from 16 to 90, and the average age was 55.5.
Fifty-four percent of the patients were men, and 76 percent were Caucasian.
These patients underwent back surgery for conditions such as:
Disc herniation (ruptured or slipped discs, the rubbery cushions between vertebrae);
Spinal stenosis (narrowing of the spinal canal); and
Degenerative disc disease (the progressive deterioration of discs).
Researchers then collected a wide range of demographic information and complications and death that occurred within 30 days after surgery for all the patients. Major complications included deep vein thrombosis (blood clots deep in the legs), sepsis (a life-threatening condition caused by a bacterial infection), deep wound infections, and unplanned return to the operating room. Minor complications included urinary tract infections, pneumonia, and superficial wound infections.
The death rate was .03 percent, (10 out of 3475 patients), while 7.6 percent (263 out of 3475 patients) experienced complications within 30 days after surgery. The preoperative and postoperative data indicated that increasing patient age and surgical wound problems independently increased the risk of death. The data also identified the following independent risk factors for developing one or more complications within this 30-day period:
Older patient age;
Congestive heart failure and/or a history of heart attack;
Preoperative neurological problems;
A history of spinal wound infection;
Use of corticosteroids;
A history of sepsis;
A classification of 3 or higher according to the American Society of Anesthesiologists physical status classification system (a system that evaluates a patient's health status prior to surgery); and
People who already have had spine surgery and those considering it should keep the results of this national study in perspective, said Dr. Schoenfeld.
"Our study only documents complications and mortality that occurred within 30 days after surgery. Many studies exist that illustrate the safety and efficacy of spine surgery, and the intent of this work was not to be alarmist. Our goal was to identify medical conditions and other factors that could be addressed prior to surgery in order to further enhance the safety of spine surgery and help achieve the best results for patients. We hope that our findings will allow surgeons, patients, and their families to have a more open dialogue and discussion regarding potential risks prior to surgery."
The American Academy of Orthopaedic Surgeons (AAOS) suggests that patients considering spinal surgery:
Tell their doctor about any and all infections, no matter how distant or unrelated they might seem;
Schedule an appointment with your primary care provider to be sure your overall health is optimized;
Stop smoking; and if need be, consider postponing surgery to undertake a fitness or weight control program.
Ends/Newswire
SA/EN
---------------------------------------------------------------
Rotating magnetic moments: spin pumping effect demonstrated for first time
Islamabad, Sep 29 (Newswire): Bochum's physicists led by Prof. Dr. Hartmut Zabel have demonstrated the spin pumping effect in magnetic layers for the first time experimentally.
The behaviour of the spin pumping had previously only been predicted theoretically. The research team at the RUB has now succeeded in measuring the effect using ultrafast X-ray scattering with picosecond resolution.
Through their rotation of the magnetic moments, the so-called magnetic precession, single electrons can mutually influence each other's rotation (spin) through a non-magnetic intermediate layer. This is a crucial insight for future generations of magnetic sensors in hard disk read heads and other data storage.
Once put into motion and left to itself, a spinning top will slow down after a few rotations and eventually come to a halt. Friction losses deprive it of energy, until it finally stops spinning. Also, two spinning tops put at a certain distance to avoid touching show by and large the same behaviour.
"In particular, we do not expect that one spinning top can affect the rotation of the other," said Prof. Hartmut Zabel. Whether both tops rotate in the same or in the opposite direction, should have no impact on the number of rotations before they come to a stop. "But that's precisely what happens with magnetic spinning tops," as Bochum's research group confirmed in its experiments.
Once triggered, the magnetic moments rotate in a crystal lattice until their rotation energy is exhausted through excitation of lattice vibrations and spin waves. Spin waves are excitations of the magnetic moments in a crystal, which propagate in form of waves.
The research team separated two ultra-thin magnetic layers with a layer of copper. The copper layer was made thick enough that the two ferromagnetic layers can have no influence on each other -- at least no static influence.
However, once one of the two ferromagnetic layers is stimulated to a very fast precession in the gigahertz range, the damping of the precession depends of the orientation of the second magnetic layer. If both layers have the same orientation, then the damping is lower. If both are oriented in opposite directions, then the damping is higher.
Up to now, it had not been possible to research the effect described as "spin-pumping" experimentally. The scientists have now been able to demonstrate the effect in the ALICE test chamber built by RUB physicists in Berlin. The precession of the magnetic moments in a ferromagnetic layer is "pumped" through the non-magnetic intermediate copper layer and absorbed by the second ferromagnetic layer. In other words, ferromagnetic layers, which do not interact with each other statically because the intermediate layer is too thick, are still able to "affect" each other dynamically through pumping and diffusion of spins from one layer to another.
The sequence of layers selected in the experiment is that of a typical spin valve. These are nano-magnetic layer structures which are used as magnetic sensors in the read heads of hard disks and which encode the logical bits "0" and "1" in non-volatile magnetic data storage.
The speed at which data can be read and written, depends crucially on the precession of the magnetic moments and their damping. "Therefore, the finding that the damping of the magnetic precession is influenced by spin pumping through non-magnetic intermediate layers is not only of fundamental but also of practical interest for industrial applications" said Professor Zabel.
While medical experts acknowledge the potential benefits of spine surgery, they also understand that complications can reduce the success in the short and long term.
"Complications following spine surgery may have a substantial impact on the quality of life of patients as well as the outcome of the primary surgical procedure," said orthopaedic surgeon Andrew J. Schoenfeld, MD, one of the authors of a new study recently published in the Journal of Bone and Joint Surgery (JBJS). This study identified several risk factors for a variety of complications and death shortly after spine surgery among men and women across the U.S.
Relatively few studies have explored the impact of factors such as comorbid medical conditions (simultaneously and usually independently existing health problems, including diabetes and cardiovascular conditions), age, body mass index (BMI), and gender on the risk of complications following spine surgery. Most research to date has focused exclusively on wound infection, and few studies have explored other possible complications and death.
"At the present time, the results of this study may represent some of the best available evidence regarding risk factors for complications and mortality following spine surgery," said Dr. Schoenfeld.
The study authors evaluated the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database for the years 2005 to 2008. This database documents preoperative information and postoperative complications and death among patients receiving surgery at participating medical facilities across the United States.
"One of the principle advantages of the NSQIP dataset is that it encompasses patients in selected hospitals from across the United States and includes a variety of spine surgical procedures," said Dr. Schoenfeld.
The study authors identified patients who received one or more spine operations. From 2005 to 2008, 3,475 spine-surgery patients were registered in the database.
They ranged in age from 16 to 90, and the average age was 55.5.
Fifty-four percent of the patients were men, and 76 percent were Caucasian.
These patients underwent back surgery for conditions such as:
Disc herniation (ruptured or slipped discs, the rubbery cushions between vertebrae);
Spinal stenosis (narrowing of the spinal canal); and
Degenerative disc disease (the progressive deterioration of discs).
Researchers then collected a wide range of demographic information and complications and death that occurred within 30 days after surgery for all the patients. Major complications included deep vein thrombosis (blood clots deep in the legs), sepsis (a life-threatening condition caused by a bacterial infection), deep wound infections, and unplanned return to the operating room. Minor complications included urinary tract infections, pneumonia, and superficial wound infections.
The death rate was .03 percent, (10 out of 3475 patients), while 7.6 percent (263 out of 3475 patients) experienced complications within 30 days after surgery. The preoperative and postoperative data indicated that increasing patient age and surgical wound problems independently increased the risk of death. The data also identified the following independent risk factors for developing one or more complications within this 30-day period:
Older patient age;
Congestive heart failure and/or a history of heart attack;
Preoperative neurological problems;
A history of spinal wound infection;
Use of corticosteroids;
A history of sepsis;
A classification of 3 or higher according to the American Society of Anesthesiologists physical status classification system (a system that evaluates a patient's health status prior to surgery); and
People who already have had spine surgery and those considering it should keep the results of this national study in perspective, said Dr. Schoenfeld.
"Our study only documents complications and mortality that occurred within 30 days after surgery. Many studies exist that illustrate the safety and efficacy of spine surgery, and the intent of this work was not to be alarmist. Our goal was to identify medical conditions and other factors that could be addressed prior to surgery in order to further enhance the safety of spine surgery and help achieve the best results for patients. We hope that our findings will allow surgeons, patients, and their families to have a more open dialogue and discussion regarding potential risks prior to surgery."
The American Academy of Orthopaedic Surgeons (AAOS) suggests that patients considering spinal surgery:
Tell their doctor about any and all infections, no matter how distant or unrelated they might seem;
Schedule an appointment with your primary care provider to be sure your overall health is optimized;
Stop smoking; and if need be, consider postponing surgery to undertake a fitness or weight control program.
Ends/Newswire
SA/EN
---------------------------------------------------------------
Rotating magnetic moments: spin pumping effect demonstrated for first time
Islamabad, Sep 29 (Newswire): Bochum's physicists led by Prof. Dr. Hartmut Zabel have demonstrated the spin pumping effect in magnetic layers for the first time experimentally.
The behaviour of the spin pumping had previously only been predicted theoretically. The research team at the RUB has now succeeded in measuring the effect using ultrafast X-ray scattering with picosecond resolution.
Through their rotation of the magnetic moments, the so-called magnetic precession, single electrons can mutually influence each other's rotation (spin) through a non-magnetic intermediate layer. This is a crucial insight for future generations of magnetic sensors in hard disk read heads and other data storage.
Once put into motion and left to itself, a spinning top will slow down after a few rotations and eventually come to a halt. Friction losses deprive it of energy, until it finally stops spinning. Also, two spinning tops put at a certain distance to avoid touching show by and large the same behaviour.
"In particular, we do not expect that one spinning top can affect the rotation of the other," said Prof. Hartmut Zabel. Whether both tops rotate in the same or in the opposite direction, should have no impact on the number of rotations before they come to a stop. "But that's precisely what happens with magnetic spinning tops," as Bochum's research group confirmed in its experiments.
Once triggered, the magnetic moments rotate in a crystal lattice until their rotation energy is exhausted through excitation of lattice vibrations and spin waves. Spin waves are excitations of the magnetic moments in a crystal, which propagate in form of waves.
The research team separated two ultra-thin magnetic layers with a layer of copper. The copper layer was made thick enough that the two ferromagnetic layers can have no influence on each other -- at least no static influence.
However, once one of the two ferromagnetic layers is stimulated to a very fast precession in the gigahertz range, the damping of the precession depends of the orientation of the second magnetic layer. If both layers have the same orientation, then the damping is lower. If both are oriented in opposite directions, then the damping is higher.
Up to now, it had not been possible to research the effect described as "spin-pumping" experimentally. The scientists have now been able to demonstrate the effect in the ALICE test chamber built by RUB physicists in Berlin. The precession of the magnetic moments in a ferromagnetic layer is "pumped" through the non-magnetic intermediate copper layer and absorbed by the second ferromagnetic layer. In other words, ferromagnetic layers, which do not interact with each other statically because the intermediate layer is too thick, are still able to "affect" each other dynamically through pumping and diffusion of spins from one layer to another.
The sequence of layers selected in the experiment is that of a typical spin valve. These are nano-magnetic layer structures which are used as magnetic sensors in the read heads of hard disks and which encode the logical bits "0" and "1" in non-volatile magnetic data storage.
The speed at which data can be read and written, depends crucially on the precession of the magnetic moments and their damping. "Therefore, the finding that the damping of the magnetic precession is influenced by spin pumping through non-magnetic intermediate layers is not only of fundamental but also of practical interest for industrial applications" said Professor Zabel.
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