Bringing Home the Back Pain

People joke that many dogs and dog owners look alike. Researchers at the Tulane School of Public Health in New Orleans report a similar phenomenon among back pain sufferers. They found that people living with someone who has disabling back pain often start to have the same kind of pain. Other members of the household are also more likely to have a back injury that keeps them from getting back to work.

Some researchers call this the “pain-prone family.” In this case, it’s not inherited. It’s behavior that’s modeled and imitated. The spouse of an injured worker develops a pain pattern very much like the injured or disabled worker. This can also happen to partners or other family members living with the disabled worker.

In this study the patients had a work-related spine injury (WRSI). None of the injured subjects could work anymore. The nonworking WRSI patients were compared to a second group. The second group had a WRSI, but they were still working. Data was collected about each group of patients from their medical charts. Each one was also contacted by phone whenever possible.

The authors report that several factors predict disability after a work-related injury. Predictors include gender (more women have back pain than men), area of spine involved, and severity of injury. But none of these predictors was as strong as having a family member with a similar disability.

The authors of this study think that knowing about this predictor may help find the workers who are at risk for chronic back pain after a WRSI. Treatment and management of such workers may change based on knowing how social issues affect their recovery.

First Trial of Radiation to Reduce Scar Tissue around Spinal Nerves

Researchers are looking for a way to prevent scar tissue after back surgery. This is the first known study to include humans. The treatment for scar tissue build-up is low-dose radiation. The radiation takes place 24 hours before a second operation to remove the scar tissue.

Usually a second operation isn’t even advised. Doctors fear more scar tissue will form and make the problem even worse. Radiation injures the cells that go to work after a specific trauma like surgery. These cells, called fibroblasts, normally rush to the site of trauma and try to repair it. The problem is that too many cells come to help. The resulting dense scar tissue is called fibrosis.

Fibrosis can wrap itself around the spinal nerve and the nearby tissues. Then the nerve can no longer slide and glide in its outer covering. This condition is called tethering. Low-dose radiation to prevent fibrosis has worked well in animal studies. The results of this study show some promise for its use with humans, too.

Five patients were treated with low-dose radiation. Five others were given what looked like radiation treatment, but no radiation was delivered. In the radiation group three patients were pain free and two were had less pain after the treatment. In the control group, three patients were better and two had no change. No one was pain free in the control group.

This study was cut short when a product used in the operation was pulled off the market. The researchers couldn’t treat everyone the same and had to stop the study with only 10 subjects. The study may be redesigned and redone. It appears that in a small group of patients with fibrosis who are having a second operation, low-dose radiation improves the final results.

Spine Operations by Orthopedic Surgeons

Anytime you have major surgery, your doctor has help. There are nurses, anesthetists, and surgical assistants. Other doctors are involved, too. In the case of spinal surgery, the extra doctor may be a general surgeon. A specialist in the heart and blood vessels called a vascular surgeon may be on hand.

Who does a better job? The orthopedic spine surgeon or the doctor who is assisted by another specialist? This is the focus of a study from a United States spine surgeon. Only one type of operation was reviewed: anterior spinal surgery. In these surgeries, the body is opened from the front. The reason for the surgery varied among the 450 patients enrolled. Some had spinal deformities. Others had fractures, tumors, infection, or disc disease.

The researchers compared complications due to the method used to open the body. Problems included amount of blood loss, length of surgery time, number of deaths, and number of blood vessels damaged. The researchers found a big decrease in problems among patients treated only by an orthopedic surgeon. Problems in the group operated on by an orthopedic surgeon along with another surgeon were much higher.

The authors conclude that orthopedic surgeons should be able to operate on the spine using an anterior approach without the assistance of another surgeon. In many places orthopedic surgeons aren’t allowed to do this without special training. Some centers don’t allow it even when the doctor is qualified.

This report supports the idea that training should be changed to include this method of spine surgery. The researchers think this training should be offered to any orthopedic surgeon who wants to get approval for these techniques.

Total Disc Replacement Replaces Spinal Fusion When All Else Fails

Surgery to fuse the lumbar spine doesn’t always work. Research shows it’s getting better, with 80 percent success in the short run. This is up from the previously reported 50 percent. But there are still problems with pain from the bone graft, bracing, and unwanted motion at the fusion site.

If fusion is the last step in treatment, what can be done next? Try total disc replacement (TDR). The TDR implant preserves motion and normal spinal alignment. This prevents more damage in the spine. With a spinal fusion, the loss of motion at the fused area transfers the force and load to the level above or below it. The result is degeneration of these segments.

This is the longest study so far showing the results of TDR. Forty-two patients received a special replacement disc called a Prodisc prosthesis. They were followed for an average of eight years. Range of motion at the level of the disc replacement and damage at the levels above and below were measured.

The researchers report at least two-thirds of the patients kept their forward and backward motion in the low back area with a TDR. This is important. Without the motion, there’s no difference between a TDR and a fusion. They found that women are less likely to have as much motion as men. The reasons for this are unclear.

The authors report that there are still a lot of unknowns in this area of research. How much motion is needed to avoid problems? Why do women tend to have less motion after TDR compared with men? How does the Prodisc model compare to others now on the market? How does TDR compare to fusion 10 or even 20 years later? More research is planned by these scientists to find some answers.

Early Results of Total Disc Replacement Reported

False teeth. Breast implants. Pacemakers. Hip and knee joint replacements. Heart transplants. Seems like more and more body parts can be repaired, removed, or replaced. What’s next?

Disc replacements! Actually, researchers have been studying disc replacements for the spine since the 1950s (even before heart transplants were available). There have been more than 70 patents issued for these devices. Only a few have actually been put to use in patients.

The most common total disc replacement (TDR) is one from Germany called the SB Charité III. The III means it’s the third design of the device. The first two were prototypes. Only the third one has actually been used in patients.

There aren’t too many studies on the results of TDR with this implant. So far all the reported studies have been positive. This study from the Texas Back Institute adds to that list. Of the 57 patients getting the SB Charité III, everyone got pain relief and better function. The results were still good two years later. None of the implants failed. There were no fractures, slippage, or dislocation of the TDRs.

The doctors at the Texas Back Institute aren’t stopping here. They want to combine data collected from many centers to see the results in a large number of patients. They want to know how TDRs compare with fusion cages used in similar patients. They are already planning to let us know the results in the near future.

Measuring Your Exertion while Exercising

If you do much exercising, you’ve probably heard of the rating of perceived exertion (RPE). It’s a way to pick a number to equal how hard you feel you are working. Sometimes the scale goes from zero to 10. Another scale goes from six to 20. The lower numbers are for a light workout, and the higher numbers are for harder workouts.

Physical therapists in England studied back pain patients using RPE while exercising in a pool. They found at low workloads (not enough to be aerobic), the RPE wasn’t a very good measure of intensity. Once the patients got their heart rates up to at least 55 percent of their maximum, RPE was accurate. Used this way, it predicts a safe exercise intensity.

This is important because back pain can lead to reduced activity. Then the patient gets deconditioned and weak. The heart and lungs don’t work as well. Pool therapy can help improve this while also reducing back pain. Since everyone has a different response in the water, some way to self-regulate intensity is needed. The authors of this study suggest using the RPE Scale for those patients in a pool program who are able to get their heart rate up high enough.

Pulsed or Thermal Radiofrequency for Back Pain?

Radiofrequency (RF) can be used to treat painful neck or back symptoms coming from the small joints along the back of the spine. These joints are called the facet joints. Used in this way, RF is a high-frequency alternating electrical current. RF can heat up and destroy tissue. When used this way, it is called thermal RF.

Thermal RF for the treatment of neck or back pain has some risks. It can cause inflamed nerve tissue. If the nerve to the muscles along the spine, the multifidus muscles, is destroyed, the spine can become loose, or unstable.

A new way to use RF is tried in this study. Doctors at the Pain Medicine Program from the Medical College of Georgia used pulsed RF instead of thermal RF. Pulsed RF doesn’t heat up the tissue. It disrupts messages sent by the nerves without destroying them.

Pulsed RF is a painless treatment for neck or back pain when the problem is the facet joint. Used on 114 patients, more than half reported greater than 50 percent pain reduction. None of the patients had any problems with the treatment.

The authors report that pulsed RF is a safe and helpful treatment for joint-induced neck or back pain. The effects last up to four months, so the good effects are only temporary. The hope is that the joint will recover during this time. Patients will also have increased mobility and activity during the pain-free period.

Fitting the Worker to the Workplace

So what is it with back pain, anyway? If researchers are right, then over 80 percent of working adults are going to have low back pain (LBP) sometime. Is it the worker’s size or height that makes the difference? Or is it personality? The workplace? Mental stress?

Researchers at the Low Back Biomechanics and Workplace Stress Laboratory in Cincinnati are trying to find some answers to these questions. This study looked at 60 college-aged subjects (30 men and 30 women). No one had back pain or a history of back pain. Each person lifted boxes from a conveyor in front to a shelf on one side or the other. The lift rate was two lifts per minute to eight lifts per minute. A lumbar motion monitor measured trunk motion during the lifting. Electrical activity of the muscles was also measured.

There are two kinds of load on the spine: compressive and shear. Compression is the load straight down through the spine from top to bottom. Shear is the side-to-side force of one bone against another.

In this study body size, height, and shape had a big effect on the shear force. Personality and gender also made a difference. Compression load was based on the weigt of the load. The researchers also found that muscle activity is affected most by gender, load weight, and body type. Body size and shape had the greatest influence on trunk motion and posture when lifting. Mental concentration didn’t seem to have an impact on spinal loads or muscle activity.

The authors say the most surprising finding is the effect of load placement as a unique stressor. Load placement refers to where the box is held (close to the body or away from the body) and how it’s lowered to the shelf. They conclude that the worker and workplace need to be a good match. Workplace design such as adjustable shelves may be one place to start. Other adjustable equipment may reduce the effect of different worker heights, sizes, and shapes. Knowing what factors put the greatest load on the spine may lead to better ways to prevent LBP.

Comparing Spine Fusion with and without Growth Factors

You’ve heard of the search for the Holy Grail? Well, it doesn’t hold a candle to doctors’ search for better ways to fuse the spine. The newest player in bone fusion is autologous growth factor (AGF).

AGF is taken from the patient’s blood and mixed with bone taken from the patient’s hip. Growth factors in AGF cause bone cells to make more bone cells. The mixture of AGF and bone graft is then placed in and around the spinal joints.

This is the first study to try this method on humans. Up until now animals have been used. One orthopedic surgeon divided his patients into two groups. The first group had one spinal level fused using just their own donated bone. The second group had one spinal level fused using self-donated bone mixed with AGF. Both groups had the same diagnosis of spine or disc degeneration.

The results were no better than in animal studies. The group with just bone graft to fuse the spine had a solid fusion 91 percent of the time. The group with the growth factor had a fusion rate of 62 percent. The results were not sufficient enough for these researchers to recommend the use of AGF in spinal fusions–at least not without more study.

The authors tried to explain their results. It may be that AGF combines with a bone protein called bone morphogenic protein (BMP).When put together, these decrease bone formation. The authors think what they used may be too concentrated and doesn’t mimic natural amounts of AGF.

Other ways to get and use AGF must be studied. The goal is to find a safe an inexpensive way to fuse the spine quickly without side effects or problems.

Which is Worse: Neck Pain, Arm Pain, or Both?

Your lifetime risk of getting prostate or breast cancer is one in eight. Your chances of developing neck or back pain are much higher. In fact about 80 percent of all adults will suffer back pain at some point in their lives. Neck pain affects three-fourths of all adults.

Neck and back pain can become chronic, incurable problems. Neck pain often comes along with arm pain. These problems can impact your ability to do things physically and socially. They can even affect your mental health.

Doctors from the Department of Orthopaedic Surgery at the Thomas Jefferson University in Philadelphia surveyed 1,809 patients with neck and/or arm pain. They found that younger patients are more affected by symptoms than patients over 60 years of age. The longer the symptoms last, the greater the effect on mental health.

The researchers also found that patients with neck and arm pain were affected the most, even more than patients with just neck or just arm pain. The authors say this makes sense because shooting pain down the arms with weakness, numbness, and tingling every time the neck moves is disabling. They also think younger patients are affected more because the physical demands of their lives are greater. For example, patients under age 40 are often caring for children and working full-time.

Most older patients get better after a bout of neck and/or arm pain. Treating younger patients quickly is advised to avoid chronic symptoms. Doctors who wait too long to treat patients with neck and arm pain may put their patients at risk for related psychologic problems.

Bracing for Scoliosis: 22 Years down the Road

It’s important for doctors and patients to know the long-term effects of different treatments. That is not always possible, at least not for many years. For example, how well do braces help children who have scoliosis, a sideways curve of the spine? Researchers in this study looked at the long-term effects of treating scoliosis in children. They wanted to know how a group of patients was doing 22 years later.

A group of adults who had worn back braces as children were compared to a group of healthy adults. Both groups got physical exams and X-rays. The two groups answered questions about health, back function, and activities. The differences between the two groups were no surprise. The brace group had more degeneration in the bones of the spine. They still had curves in the spine. In more than one-third of the brace group the curves were actually worse than they had been when the participants were children. The brace group reported more back pain. They had taken more time off work because of back pain. And they reported being fearful of back injury and not liking the way their bodies looked more often than the control group.

This may sound bad. But the results were actually quite positive. The brace group had more back pain, but it was fairly mild. These individuals used very little pain medication. Their back function scores were only slightly lower than the control group. For most people, the brace they wore 22 years ago didn’t seem to affect their daily life much.

These authors have also done follow-up studies of children who’d had surgery to correct scoliosis. They note that both bracing and surgery patients seem to have about the same pain and function 22 years down the road.

Activity Not Linked to Back Pain in Kids

Back pain sometimes begins in childhood. Recently there has been much concern about the causes of back pain in kids. Many studies find that couch-potato kids are more likely to have back pain. Some studies suggest that kids who do sports too hard are at higher risk for back pain. And all these studies have one major problem: the kids report their own levels of physical activity. How accurate are their reports? And how does that affect
the studies?

These authors designed this study to answer those questions. They looked at back pain in more than 800 kids in Denmark. All the kids answered questions about back pain and their level of physical activity. But the researchers also hooked the kids up to a device called an accelerometer. It measured how much and how fast the kids were moving. The kids wore it for four days.

The results showed no link between activity levels and back pain. There was also no strong link between the activity levels reported by the kids and the activity levels shown by the accelerometer. This is an important finding. It questions the accuracy of any study that involves just asking kids their activity level.

The authors say this is the first study of its kind. No other study done with children used a device to measure their activity levels. This makes the results more reliable.

But the study has its limitations. The accelerometer can’t tell what type of activity someone is doing. It is possible that back pain in kids is related to the type of activities they do. The authors also note that studies like this should be done at different times of year. Kids are probably more active during some parts of the year than others.

New Imaging Method May Someday Make Spine Surgery Easier

Spine surgery is complex. The bones, soft tissues, blood vessels, and nerves in and around the spine are important and delicate. The goal of spine surgery is to fix the problem with the least amount of damage to other parts of the back.

Advances in imaging technology have helped spine surgeons in this goal. CT scans, MRIs, and two-dimensional fluoroscopy done before spine surgery have helped increase accuracy and decrease complications. Now along comes three-dimensional (3D) fluoroscopy. This new technology will let spine surgeons take 3D pictures during surgery. The images come in on a computer within five minutes. The surgeon no longer needs to carefully match the images to the body on the table. Instead, the computer does much of that difficult work.

These doctors tested 3D fluoroscopy for placing screws in the spine of cadavers (human bodies saved for study). They used very small incisions to place the screws. They also used 3D fluoroscopy to check the placement. They had 100 percent accuracy of screw placement in the lower back. Accuracy in the mid-back, which is more difficult, was 92 percent. These rates are very good compared to other surgical methods.

The authors note several benefits of 3D fluoroscopy:

  • CT scans are not necessary to prepare for surgery. This can save patients time and money. The images are also more accurate in some cases, since they are taken during surgery.
  • Accuracy is improved because the system is automated.
  • The surgeon no longer needs to go through the time-consuming step of matching the images to the spine during surgery.
  • The surgeon can check several different views of the spine in two or three dimensions.
  • The surgeon can check screw placement in the operating room.

    There are two drawbacks to 3D fluoroscopy. The equipment and software will be expensive for hospitals to set up. Also, surgeons will have to take some time to learn how to use the new technique. Still, 3D fluoroscopy shows major promise as a way to improve spine surgery.

  • Nicotine’s Effect on the Disc

    Nicotine is the major chemical in tobacco. Scientists have found that nicotine speeds up disc degeneration in the spine. They want to know how this happens. Perhaps knowing how nicotine acts on the disc will help researchers find ways to stop it.

    We already know how nicotine increases blood pressure by closing down blood vessels and making it harder for the blood to get through. Maybe a lack of blood to the disc is what also causes the damage. Or maybe nicotine has a more direct effect on the discs. This is what the authors of this study are looking at.

    The researchers took two groups of rats and harvested cells from their discs. One group had nicotine painted on the cells. The other group had no treatment. The second group was the control group used for comparison.

    They found that nicotine stops type II collagen from forming in the center of the disc. This part of the disc is called the nucleus pulposus. Collagen is a protein that makes up the fibers of soft tissues like disc, tendons, ligaments, and cartilage. The nicotine stops collage formation by cutting off a signal to a special growth factor called bone morphogenetic protein-2 (BMP-2).

    A major feature of disc degeneration is the loss of normal cells in the nucleus pulposus. The results of this study suggest nicotine’s effect on BMP-2 is the reason for this loss.

    The authors of this study think these findings may also apply to nicotine’s effect on inhibiting bone formation. For example, when the spine is fused in surgery, patients who smoke have a much slower healing rate and higher fusion failure rate. This study is just the first of many needed to unravel the mystery of nicotine’s effect on the spine.

    CT Scan Gives Insider View of Spinal Fusion

    Interbody fusion: It can’t send you to the moon or split an atom. But it can do something better–reduce back pain. Spinal fusion for back pain can now be done with mesh cages inserted between the vertebrae. The cages are usually filled with bone chips or bone substitute. This bone graft causes more bone cells to grow, connecting the bone above with the one below. This is called interbody fusion.

    But doctors don’t have a reliable way to tell if the bone graft is healing without opening up the patient and getting a look. In this study, researchers compared X-ray results with computed tomography (CT) scans. The CT scan is a special type of X-ray that lets doctors see “slices” of bone tissue. The machine uses a computer and X-rays to create these slices. The imaging studies were done six months after the surgery.

    The authors found bone growth in 95 percent of cases with CT scan. The same patients viewed by X-ray showed bone growth in only four percent of the cases. Likewise, CT scan showed bridges of bone forming around the cages in 90 percent of the patients. In those same patients X-rays showed bone bridges only eight percent of the time.

    Without a good solid spinal fusion, patients can develop movement at the fusion site. This condition is called a pseudoarthrosis. Loose cages can also occur. Finding these problems early can help plan further treatment and shorten the follow-up time.

    The results of this study show that CT scans are much better than X-rays for evaluating spinal fusion with cages. The CT scan also showed new bone growth outside and around the cages when no bone graft was used to help it along.

    Pumping Up the Spine

    When people have osteoporosis, the most common bone broken is the hip, right? Wrong. Compression fractures of the vertebrae are the most common problems of osteoporosis. They are tiny cracks in the bones of the spine. The bone becomes weak and actually collapses. When a vertebra collapses, it loses height. These fractures cause the hunchback appearance of many older people.

    A humped back is more than just a cosmetic problem. The condition, which doctors know as kyphosis, can cause pain and disability. It can even squeeze the lungs. To relieve pain, the compressed vertebrae can sometimes be filled with cement. This procedure is called vertebroplasty. It makes the bone stronger. But vertebroplasty does not restore the height of the vertebra.

    A newer procedure called kyphoplasty addresses this problem. In this procedure, a balloon is inserted into the middle of the collapsed vertebra. The balloon is then inflated. This expands the bone, and it regains height. Cement is then pushed into the space right away. The cement supports the vertebra and restores its height.

    This study followed the results of kyphoplasty patients for at least one year. Patients reported less pain right away. Pain relief lasted over the follow-up period. Patients also reported more activity and a better mental state. There were very few complications.

    The authors conclude that kyphoplasty is an effective treatment for compression fractures in the vertebrae. Over time, it may prove to be the treatment of choice for this painful condition.

    Cementing the Spine

    Vertebroplasty involves injecting cement into a damaged vertebra. The cement fills the holes and cracks in the bone. This makes the bone stronger. This treatment can be used in vertebrae that have been weakened by osteoporosis and cancer. It can relieve pain almost right away.

    One of the problems with this method is that extra cement can leak out. Doctors must estimate how much cement they will need. It is almost impossible to be exact. And the extra cement could cause problems if it gets in the wrong places. This study looked at how much cement leaks out. The authors wanted to find out if extra cement was related to pain or problems in the first week.

    Results showed that cement leaked in about 88 percent of patients. It leaked differently depending on the patient’s disease. When vertebroplasty was done for osteoporosis, the extra cement tended to leak into the disc. In patients with cancer, the extra cement leaked into many different areas.

    All patients had less pain after vertebroplasty. Leakage didn’t seem to have much effect on pain results. However, osteoporosis patients with the most leakage seemed to get slightly less pain relief.

    This study suggests that cement leakage may not be a major issue in this procedure. Still, extra cement could cause problems. And these authors only looked at results over one week. This means that long-term effects are unknown. The authors recommend that doctors inject the least amount of cement possible. Perfecting the cement injection could make vertebroplasty an even more successful procedure for relieving pain.

    New Memory Coiling Spiral Replaces Center of Disc

    What can hold two structures apart, support hundreds of pounds of weight, and withstand millions of cycles of compression? Your intervertebral disc! Problems happen when the disc is removed due to injury or disease. Scientists have tried finding solutions. They’ve tried filling the space with bone chips, inserting mesh cages filled with bone chips, and attaching plates and screws to hold it all together.

    Now there’s a memory coiling spiral to act as a nucleus pulposus implant. The nucleus pulposus is the center of the disc. It sits inside an outer shell called the annulus. Dr. J. L. Husson from France has been working on the design since 1990. The implant can be put in right after the nucleus pulposus is taken out. The annulus (the outer layer) remains in place. The coil is in the shape of a spiral. It fills the disc cavity without being tied down or glued in. A special manufacturing process allows it to hold its coiled shape
    once in place.

    The best placement for the coil is right in the center of the disc space. But it’s okay if it moves or twists inside the disc. The doctor puts the spiral right inside the disc to allow for a perfect fit. When the spiral fills the nucleus space, the annulus takes up its old functions. The risk of a new herniation is gone.

    Researchers have tested this new implant using human cadavers. Up to 50 million cycles of force were applied in all directions. No wear and tear was seen. The next step was to test it in live patients. Results from the first five patients are the subject of this report.

    After two years the implant hadn’t shifted or moved. Everyone had less pain and better function. Everyone was satisfied with the results, and four of the five patients went back to work. X-rays show that the implant is keeping the proper disc height.

    The authors think this new implant will be a good way to treat disc problems without spinal fusion. Soon it will be possible to insert the implant with a tiny incision, making it an even less invasive operation.

    Not All Disc Replacements Are Alike

    Artificial disc replacement seems like a new treatment for disc problems. It’s really been around for quite some time. The SB Charité model is the subject of this report. The SB is made of a cobalt chrome along with high-density polyethylene (manmade plastic). It has been in use since 1987. Over 5,000 of these discs have been implanted in patients around the world.

    Not all disc replacements are the same. The authors of this report name five special features of the SB:

  • It uses a plastic surface instead of metal-on-metal or ceramic-on-ceramic.
  • It has a mobile bearing design instead of ball-and-socket. This means that motion occurs around more than one point.
  • There is a porous surface to allow tissue to fill in and around. This prevents loosening.
  • It is sterilized with gamma irridation, which has been shown to be more effective.
  • It saves on that amount of bone that has to be cut out to fit the implant.

    In this study patients receiving a SB disc replacement were compared with patients who had interbody spinal fusion with bone graft. This is the first study to compare these two treatments for disc disease.

    The authors report similar results with the two treatment options. The time it took to do the two operations was about the same. Pain levels were reduced equally. Patients improved equally in function. The authors suggest that, with careful patient selection, the SB disc replacement is a good treatment alternative to spinal fusion.

  • Creative Surgical Solutions to Painful Back Problems

    Choices in back surgery are changing. Spinal fusion is the standard treatment for chronic low back pain caused by degenerating discs. But a new device, the total disc replacement (or artificial disc), is now on the market. This may change how the problem is treated.

    Disc replacements come in two kinds. There’s a partial disc replacement, which replaces just the central portion of the disc. The center of a disc is called the nucleus pulposus. Moderate disc disease can be treated with a partial disc replacement, called prosthetic disc-nucleus (PDN).

    For advanced disc disease, a total disc replacement may be needed. This involves removing and replacing the entire disc. The disc is made up of two parts: the nucleus pulposus on the inside and the outer covering called the annulus fibrosis.

    Different types of disc implants are ready for use. Doctors working with one of these companies are testing a new way to put the device into the disc space. Until now the incision was made along the back of the spine. This approach can cause problems when bone and soft tissue is cut to gain access to the disc space. The doctor must also be careful to avoid damaging the nearby spinal nerves.

    The new method gains access to the disc space through the patient’s side. Cutting through the psoas muscle along the front of the low back brings the doctor to the middle third of the disc. This approach is called the AnteroLateral transPsoatic Approach (ALPA). It can only be done at the L2-L4 spinal levels. Below that, the pelvic bone gets in the way. Later it may be possible to cut through the bone from the side and reach L5-S1 levels.

    Eight patients formed the first study group for ALPA. Half the group suffered damage to the nerve sending messages to the psoas muscle. The symptoms were temporary and went away by the third month after the operation. There was a problem with the artificial disc moving forward in the disc space. The authors think this was caused by weakness in the annulus fibers. They don’t think it happened because of the ALPA method.

    This first study shows promise using the ALPA technique for disc replacement. The authors propose using the method on a larger number of patients. Problems with nerve damage and implant migration will likely improve as the doctor gains experience with this new approach.