Image guided lumbar nerve root sleeve injection

Anatomy of the lumbar spine

Prof Mark Khangure, Dr Jason Wenderoth, January 31, 2012, 1. What is a lumbar nerve root sleeve injection? The spine is made up of bones called vertebrae. Between each vertebra is a ‘disc’ that allows the spine to be flexible. In between adjacent vertebrae, there is an opening on each side called a ‘foramen’, through which a nerve exits on its way to the buttock or leg. The nerve is surrounded by a ‘sleeve of fat’. Injection of corticosteroid (or ‘steroid’) and/or a local anaesthetic in the fat surrounding the nerve root is called nerve root sleeve injection. Corticosteroid medication decreases inflammation in the nerve root and will often reduce pain caused by nerve root inflammation, irritation of the nerve caused by arthritis or conditions such as disc degeneration or prolapsed disc (where the disc bulges). 2. Why would my doctor refer me to have this procedure? Back and/or leg pain can come from compression of the nerve as it passes through the foramen. Compression can come from a damaged, bulging disc or from extra bone that grows as a response to arthritis in the joints between the vertebrae. Inflammation from scar tissue and swelling after surgery on the spine can also irritate the nerves in the lower back. An injection of corticosteroid around the nerve root may alleviate the pain by reducing inflammation of the nerve. If the pain is suspected to come from a particular root, but it is not certain which one (especially in older people who may have root compression as a result of arthritis at a number of spinal levels), blocking the root with anaesthetic confirms or rules out that particular root as the cause. This can help in planning for future surgery. If surgery is a consideration, root sleeve injection may be used to relieve the pain before the surgery and can sometimes allow surgery to be delayed or avoided. 3. How do I prepare for a lumbar nerve root sleeve injection? Because you will be lying on your stomach during the procedure and will be uncomfortable if your stomach is too full, it is advisable to limit food intake to a light meal only, up to 2 hours before the procedure. You should wear comfortable clothes that are easy to remove and leave jewellery at home. Please note that some of the disinfectant agents used during these procedures may stain light-coloured clothing. When you make your appointment for the lumbar nerve root sleeve injection, you need to let the radiology clinic or department know if you are taking any blood thinning medication, such as warfarin, clopidogrel, dabigatran, prasugrel, dipyridamole or asasantin (for more information about these medications, go to NPS: http://www.nps.org.au/medicines). Blood thinning medications may need to be stopped for a period of days, or your normal dose reduced, before this procedure is carried out. It is very important that you do not stop any of these medications or change the dose without consulting both the radiology clinic or department and your own doctor. They will give you specific instructions about when to stop and restart the medication. These drugs are usually prescribed to prevent stroke or heart attack so it is very important that you do not stop taking them without being instructed to do so by your doctor or the radiology practice, or both. Aspirin is usually not stopped. A blood test may be required to check your blood clotting on the day of the procedure. Continue with pain medication and other medications as usual. You may be monitored for 2–3 hours after the procedure, so please allow for this. You should arrange for someone to take you home after the procedure, as it is not advisable to drive for the rest of the day as you may have numbness, weakness or other temporary side-effects after the procedure. 4. What happens during a lumbar nerve root sleeve injection? You will be asked to change into a hospital gown in a changing room. You will be taken from the changing room into the computer tomography (CT) scanning room. You will be asked to lie on the CT scanning table on a thin plastic mattress. Plastic tape with small metal markers attached to it will be taped onto your back. The scanning table will be moved into the scanner and CT images or pictures of your spine will be taken. The tape with the markers is used to mark the spot, or level, in your spine where the needle for the lumbar nerve root sleeve injection will enter the skin. The spot will be marked on your skin with a pen and the tape removed. The skin on the back is cleaned with antiseptic, which is usually very cold. The area is then covered with a sterile drape. The radiologist (specialist doctor) or other specialist doctor carrying out the procedure will inject local anaesthetic into the skin and deeper tissues in your lower back. This will numb the skin and deeper tissues. This produces a pin prick and a stinging sensation that is uncomfortable for a few seconds. You will be awake and only the area where the lumbar nerve root sleeve injection is being carried out will be numb. When the skin and muscles are numb, a thin spinal needle is then guided into place. CT scanning will be used to guide this so the doctor can confirm accurate placement of the needle. When the needle is in the correct location, contrast medium (X-ray dye) may be injected to check the needle position. Contrast medium allows the X-ray to show the blood vessels more clearly on the images. A combination of corticosteroid and long-acting local anaesthetic is then injected into the tissue surrounding the nerve root. The placement of the needle and injection of contrast into the foramen may produce some discomfort if the foramen is very tight from disc problems or a bony spur compressing the nerve root. The long-acting local anaesthetic very rapidly numbs the nerve. The area of the limb supplied by the nerve being treated goes numb, and the leg or foot may feel ‘dead’ for a while. This can be worrying when it happens, but you should be aware that the feeling and movement will recover soon. 5. Are there any after effects of a lumbar nerve root sleeve injection? 

• The leg is usually numb for a period of time. If the anaesthetic spreads into the spinal canal, the opposite leg may also be numb for a period of time (minutes to 1–2 hours).
• There may be an increase in the leg pain when the injection starts, particularly if the root in the foramen is severely compressed. The pain eases off when the anaesthetic spreads around the compressed root. 

6. How long does a lumbar nerve root sleeve injection take? The actual procedure itself takes approximately 15 minutes. You may be monitored after the procedure for 2–3 hours, so please allow for this. Monitoring occurs after the procedure to make sure any numbness, weakness or other temporary side-effects of the procedure have worn off before you go home. You may also have your blood pressure and breathing monitored after the procedure. 7. What are the risks of a lumbar nerve root sleeve injection? 

• Direct injection into the nerve root, rather than around the root, can produce intense pain. Injection into the root could damage the nerve, resulting in loss of sensation and weakness of the muscle supplied by the nerve in question. Using CT scan images to guide the procedure minimises this risk. 
• Injection of the medication into a surrounding blood vessel may mean the procedure does not work, because the medication has been carried away in the bloodstream. 
• A nerve root sleeve cyst may appear like a disc fragment in the foramen and injecting this cyst can result in headache that lasts for a few days, but is relieved by lying down and taking simple analgesia, such as paracetamol. The leakage of fluid from the cyst is what causes the headache and when this leak seals off (usually after a day or two), the headache will go away. Lying flat in bed and taking plenty of fluids will help the headache and help the tiny leak to seal off more quickly than if you carry out your normal activities.
• Injection of medication into the fluid sac surrounding the spinal nerves can occur, which causes complete numbness of both legs immediately. 
• Arachnoiditis is an inflammation of the nerves within the fluid sac, and results in chronic back and lower limb pain.The long-term risk of arachnoiditis is a potential complication if particulate steroid is injected into the spinal fluid. Checking the needle position using CT scan images with contrast before injecting the corticosteroid to ensure that the needle tip is not in the spinal fluid helps to avoid this from happening. If there is any doubt about needle position, non-particulate water-soluble steroid is used. 
• Allergic reactions to the local anaesthetic and steroid medication are rare.
• Infection of the skin and deep tissues is possible, but is rare.
• Bleeding around the puncture site may compress the nerve root, causing short-term worsening of pain. The pain will decrease when the bleeding or bruise next to the nerve root goes away, but this can take a few days.

There are very few reports in the literature of permanent leg weakness and bladder function problems (paraplegia) after this procedure. This rare risk is thought to be caused by unintentional injection of one of the arteries that is a branch of an artery that supplies the spinal cord, and the use of particulate corticosteroids. It is thought that using non-particulate corticosteroids and checking that the needle is not in a vessel before injecting the steroid medication reduces or eliminates this complication. Overall, the risks are minimal when carried out by experienced specialist doctors using CT image guidance. Approximately 7 in every 1000 patients will have some type of complication from this procedure and the severe complications (such as permanent nerve root damage) are rare. 8. What are the benefits of a lumbar nerve root sleeve injection? The benefits of a lumbar nerve root sleeve injection include temporary or long-term relief of back and nerve root pain. Breaking the pain cycle aids in healing. Pain relief also makes you more comfortable, allowing the disc protrusion to shrink. This may delay or remove the need for surgery. 9. Who does the lumbar nerve root sleeve injection? Lumbar nerve root sleeve injections are usually carried out by radiologists. The doctor carrying out the procedure needs to be appropriately trained in carrying out procedures using CT imaging and experienced in carrying out this procedure. Sometimes the procedure is carried out by pain management specialists, usually using X-ray imaging. 10. Where is a lumbar nerve root sleeve injection done? The procedure is carried out in a radiology practice, a radiology department in a hospital, an operating theatre with CT and X-ray imaging or an angiography suite. Wherever the procedure is carried out, there is a requirement for post-procedure observation beds and nursing care in order to identify and treat any of the complications that can sometimes occur after the procedure. 11. When can I expect the results of my lumbar nerve root sleeve injection? The time that it takes your doctor to receive a written report on the test or procedure you have had will vary, depending on:

• the urgency with which the result is needed;
• the complexity of the examination;
• whether more information is needed from your doctor before the examination can be interpreted by the radiologist;
• whether you have had previous X-rays or other medical imaging that needs to be compared with this new test or procedure (this is commonly the case if you have a disease or condition that is being followed to assess your progress);
• how the report is conveyed from the practice or hospital to your doctor (in other words, email, fax or mail).

Please feel free to ask the private practice, clinic or hospital where you are having your procedure when your doctor is likely to have the written report. It is important that you discuss the results with the doctor who referred you, either in person or on the telephone, so that they can explain what the results mean for you. 12. Further information about lumbar nerve root sleeve injection. The procedure is effective if there is an accurate diagnosis as to the cause of the pain. If there is no nerve root compression or irritation at the level of the injection, there will be little or no response. Does the procedure need to be done under general anaesthesia? No. The most uncomfortable part of the procedure is the initial injection of local anaesthetic. After this, the rest of the procedure is usually not especially painful. Source: Inside Radiology

Read More........→January 08, 2015

When a PC Knows Its Owner

Perceptual computing describes a computer's ability to understand voice, hand and facial gestures. Anil Nanduri, director of perceptual computing solutions and products at Intel, describes how computers can
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Read More........→February 16, 2013

Look into mobile, get your eyes tested

Soon, your phone will have one more function - telling you whether you need glasses or not. A team headed by Indian-born researcher Ramesh Raskar at the Massachusetts Institute of Technology (MIT) has developed a software and a smartphone accessory that can perform eye tests and  save you a trip to the optometrist. "We have conducted scientific trials and hope to market the instrument in India in the next few months," Raskar, associate professor in media arts and sciences at MIT, told HT. The device called NETRA (Near Eye Tool for Refractive Assessment) can be clipped on to a mobile phone with a suitable hi-resolution LCD display. It can then detect whether you need glasses. The test takes less than a minute. Raskar explained that after attaching the device, those with perfect vision will see a single line, while shortsighted or longsighted people will see multiple or distorted lines. It will also help people figure out the power of the glasses they need. "Eyecare is a low priority area in India. Eyeglasses can help almost 300 million people," Raskar said. Source: Hindustan Times, Image: flickr.com

Read More........→October 31, 2012

When doing favors, monkeys don't keep score

Humans may not be unique in the ability to assist strangers.

By: By Lisa Newbern, While exchanging favors with others, humans tend to think in terms of tit-for-tat, an assumption easily extended to other animals. As a result, reciprocity is often viewed as a cognitive feat requiring memory, perhaps even calculation. But what if the process is simpler, not only in other animals but in humans as well? Researchers at Emory’s Yerkes National Primate Research Centerhave determined monkeys may gain the advantages of reciprocal exchange of favors without necessarily keeping precise track of past favors. Malini Suchak, an Emory graduate student, and psychologistFrans de Waal, director of the Living Links Center at Yerkes, led the study. Their findings will appear online in the Proceedings of the National Academy of Sciences this week. "Prosocial is defined as a motivation to assist others regardless of benefits for self,” Suchak explained. "We used a prosocial choice test to study whether direct reciprocity could promote generosity among brown capuchin monkeys. We found one monkey willing to do another favors if the first monkey was the only one to choose, and we found the monkeys became even more prosocial if they could alternate and help each other. We did not find any evidence that the monkeys paid close attention to each other's past choices, so they were prosocial regardless of what their partner had just done.” Suchak and de Waal suggest the synchronization of the same actions in alternation creates a more positive attitude the same way humans who row a boat together or work toward a shared goal develop a more positive attitude about each other. The capuchin monkeys were prosocial whether they were paired with a familiar partner from their own group or a partner from a different social group. "This research has several implications for better understanding human behavior,” de Waal said. “First, we observed an increase in prosocial behavior as a result of reciprocity, but the monkeys did not develop a contingency between their own and their partners' behaviors. Like humans, the capuchins may have understood the benefits of reciprocity and used this understanding to maximize their own benefits. Second, that the capuchins responded similarly to in-group and out-group partners has implications for the commonly held view that humans are unique in their ability to cooperate with strangers.” The researchers tested 12 brown capuchin monkeys in pairs on a prosocial choice task. The monkeys had the choice between a selfish token that benefited only them and a prosocial token that benefited themselves and a partner. By comparing each monkey's behavior with a familiar partner from the monkey's own group and a partner from a different social group, the researchers examined the influence of each monkey's relationship outside the experimental context on prosocial behavior. There was no difference between in-group and out-group pairs in any of the test conditions. To test the role of reciprocity, the researchers allowed the monkeys to take turns making choices and found this greatly increased prosocial behavior, but the researchers did not observe any tit-for-tat behavior. The researchers also tested whether the monkeys could overcome their aversion for inequity by creating a situation in which both individuals could provide each other with superior rewards, making reciprocity an even more attractive strategy. The monkeys did, but again without keeping track of each other's choices. Finally, through a series of control conditions, the researchers established the monkeys were responding to their partners' behaviors, rather than the rewards delivered by their partners, and that the monkeys understood the values of the tokens and were flexibly responding to changing conditions throughout the test sessions. Source: eScienceCommons

Read More........→September 12, 2012

Nanotechnology breakthrough could impact on life-like telepresense

Thomas is working with gold nanoparticles and studying their properties when they are shrunk into a small size regime called nanoclusters. Nanoparticles are already microscopic in size, and a nanometer is about 1/80000 of the thickness of a single strand of human hair. Nanoclusters are on the small end and nanocrystals are on the larger end of the nanoregime. Nano clusters are so small that the laws of physics that govern the world people touch and smell aren’t often observed. Thomas and his team found that nanoclusters developed by adding atoms in a sequential manner could provide interesting optical properties. It turns out that the gold nanoclusters exhibit qualities that may make them suitable for creating surfaces that would diffuse laser beams of high energy. Apart from applications in defense in protecting pilots from laser beams, Thomas also thinks that these nanoclusters could improve the sensitivity of semi-relfective films to light. This could lead to Pepper’s Ghost style solutions which require much less of a controlled lighting environment to create the illusion and make them considerably more practical in the installed environment rather than just as stage gimmicks for rock stars and CEOs. Source: InAVate

Read More........→September 11, 2012