Archive for the ‘Back pain’ Category

Sunday, April 28th 2013

The Government Telling You What Drugs You Can Take Is A Balancing Act

What’s the substantial difference between hydrocodone or dihydromorphone or diacetylmorphine? Beyond their manmade designations. Their potential risks versus their potential benefits are difficult things to quantify. In some studies diacetylmorphine is a better analgesic than morphine; nowadays, at least in the United States, only the criminal can tell us anecdotally. The various governments of our federal republic nominally weigh the risk versus reward of all controlled substances in determining under what conditions they will allow them.

It is true that government regulatory behavior appears to influence clinical providers utilization of opiates. But considering physicians can’t even agree on the appropriate use of the opiates the government does lend them to use,

It is unlikely these standards will be developed until there is a consensus among pain specialists about opioid use for nonmalignant pain because boards/agencies have no consistent, reliable source of expert information: Pain specialists should initiate efforts to develop this consensus.

Long term opiates for nonmalignant chronic conditions remain a controversial subject. I say that despite their wide use. Many factors including many psychological and social and financial factors that favor benefit from opiates play into any improvement (or lack thereof) in such pain. And the long term benefit from opiates in a condition like chronic back pain is questionable at best despite the fact such drugs may be the only thing that seems to make your loved friend or family functional. To be fair, not as dubious as surgery itself often.

Nor, as above, is the utilization of opiates, even amongst pain specialists, standardized for such conditions. It is remarkable both the variations amongst clinicians in opiate use for nonmalignant pain and the factors that influence such use. So a belief your personal health care providers know best for your pain may be an inadequate argument against government regulation of opiates.

I’m not a fan of government regulation of opiates whether in a medical setting

My wife suffers from chronic pain…she…requires daily narcotic pain medication to manage her pain.

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My wife is not the criminal. Colorado and the DEA are forcing her to live in pain as they restrict her legal access to pain relief. No one should have to watch the person they love suffer in unimaginable pain just because of bureaucratic hurdles put in place to slow illegal drug use.

…or for personal treatment or other reasons. The point of this post is the distinction is smaller than you may imagine. “[I]llegal drug use” is whatever the government says. Philosophically is there much difference between restricting the hours when you can get morphine from a pharmacy and making the very possession of heroin out of the lab illegal?

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Thursday, October 11th 2012

Fungal Meningitis After Epidural Steroid Injections

While only level II evidence through the literature I am a firm believer in epidural steroid injections for the short term relief of radicularesque pain. As most etiologies of this type of pain over the long term improve with or without surgery, epidural steroid injections can be a part of controlling symptoms in the short term while the disease process itself, usually a nerve pinched by a disc, improves. I refer plenty of patients, with symptoms that are very young or symptoms that are poorly localized or symptoms I think otherwise may be poorly responsive to decompressive surgery, to pain specialists for consideration of injections.

While hematoma, intravascular embolic events, and infection are all well reported after epidural steroid injections the procedure generally has a low complication rate; seemingly lower than a minimally invasive surgery for decompression of a nerve root. So while I know that reasonably this recent outbreak of fungal meningitis associated with contaminated compounded steroid used in epidural steroid injections does not raise the risk for any patient I refer for such in the future, and should not likely in anyway influence a referal for such, it is still a little scary.

About 13,000 people may have been exposed to the tainted steroid that has been linked to a growing outbreak of fungal meningitis, a spokesman for the Centers for Disease Control and Prevention said.

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The company that made the drug, the New England Compounding Center in Framingham, Mass., has shut down, surrendered its license and recalled all its products, not just the steroid.

The disease centers said that the company began shipping potentially contaminated lots of the drug on May 21, and that people who had the treatment for back pain — called a lumbar epidural steroid injection — after that date should seek medical attention if they develop symptoms like severe or worsening headache, fever, stiff neck, dizziness, weakness, sensitivity to light or loss of balance.

The death toll from the exerohilum and aspergilis meningitis has risen to 14. That’s about a 10% mortality so far considering just under 170 cases have been reported. The CDC has a website listing recommendations for those afraid they may have been exposed, as well as a list of the facilities which used the recalled methylprednisolone. It is scary and a reminder that even the simplest procedures hold inherent risks, but it shouldn’t move us off rationally judging those risks and continuing to use effective treatments when warranted.

Wednesday, May 9th 2012

Electromyographic Thresholds After Thoracic Screw Stimulation Depend on the Distance of the Screw From the Spinal Cord and not on Pedicle Cortex Integrity

Background

Since Dawson demonstrated it in humans in 1946-1947 monitoring SSEPs during spinal surgery has become the norm rather than an exceptional available tool. It has spread from high risk deformity correction surgeries, such as scoliosis, to more mundane and typical procedures like fusions for trauma or degenerative disease.

Neuromonitoring during spinal surgery has become a huge industry and while population sized reports show a 50% decrease in neurological complications since monitoring came into wide use not all monitoring appears created equal and prospective studies trying to tease out the benefit of costly neuromonitoring have been inconclusive at best.

One of the newer additions to neuromonitoring is evoked EMG. And here is where the paper by Montes, et al out of the Hospital Ramon y Cajal in Madrid. In evoked EMG you stimulate something, usually the pedicle screw in spinal fusions, and see if the stimulation is conducted to neural tissue. The lower the level of stimulation required supposedly the closer the screw is to damaging a neural element (the spinal cord or a nerve, etc). One of the primary fears when placing these pedicle screws is placing the screw so that it is out of bone and in the spinal canal. It is a long held belief with EMG in neuromonitoring that stimulating the screw might give you evidence if you’ve broken through the bone medially. If the stimulation of the screw evoked a response at a low enough threshold then you removed the screw and replaced.

In an animal model the pediatric orthopedic practice in Spain wanted to see if there was a relationship between the stimulation needed to evoke a motor response in each screw and the integrity of the medial wall of the pedicle.

Design
Montes, et al used a porcine model. They placed a total of 18 viable screws in the thoracic columns of anesthetized pigs. The placed screws were measured and found 8mm from the spinal cord. With leads in the intercostal muscles the screws were stimulated in this position, 8mm from the cord with the medial pedicle bone intact, and the threshold at which stimulation of the muscle was achieved was recorded. The team then placed different materials in the canal, between the medial border of the pedicle (and the screw) and the dural sac. This organic material included bone, fat and muscle. With these interspersed tissues the EMG thresholds were again recorded. The team then removed the screws, took off some medial pedicle bone creating a “breach” and then replaced the screw so that it was 2mm from the spinal cord. EMG thresholds recorded the team then repeated the thresholds with fat, bone and muscle between the screw and the dural sac.

Results

The only association with the threshold for stimulation was the distance from the spinal cord.

The tissues between the screw made no difference. So whether the medial pedicle wall was intact or not had no effect at what stimulation there was a response in the muscle.

Discussion
It is true that other in vitro studies have shown that stimulation relates to the impedence from the screw to the neural elements (ie the tissues between the screw and the spinal cord) and the authors provide no answer for the discrepancy.

Taken alone these findings argue against somewhat the usefulness of evoked EMG in spinal fusion surgery in some ways. EMG cannot really give us a high sensitivty for breach of the pedicle cortex.

All EMG leaves us with is to have a very high tolerance for borderline thresholds on stimulation. The screws that should be replaced are those that have very, very low thresholds on EMG implying that they are touching or nearly touching neural elements. That in and of itself may still be of some use as its probably that proximity, more than the violation of the bone, that most puts patient at risk for injury (ie, even if there is no intervening tissue between the screw and the cord the fact that there’s some distance is safe in and of itself).

Tuesday, November 8th 2011

A Critical Review of Recombinant Human Bone Morphogenetic Protein-2 Trials in Spinal Surgery

Background

  • Although the specifics of assessment and technique in fusion remain for debate spinal fusion for pain with spinal instability has become a generally accepted treatment
  • Surgery for fusion attempts to promote new boney growth between the unstable vertebral segments
  • Early last decade saw the rise in the clinical use of a naturally occurring cytokine, bone morphogenic protein-2, which serves to promote osteoblast differentiation and new bone formation in the body
  • Initial studies demonstrated great success, as compared to bone grafts alone, in promoting boney fusion between unstable segments when BMP was used during surgery
  • The Spine Journal June 2011 issue is dedicated to editorials and studies reviewing the growing evidence that BMP use has a number of risks that were underreported as adverse events in the initial studies which trumpted its use. Amongst these studies is a literature review by Carragee et al which criticizes the lack of reported adverse events in the initial industry sponsored BMP studies

Carragee, Eugene, Eric Hurwitz, and Bradley Weiner. “A Critical Review of Recombinant Human Bone Morphogenetic Protein-2 Trials in Spinal Surgery: Emerging Safety Concerns and Lessons Learned.” The Spine Journal 11 (2011): 471-91.

Design

  • Systemic review looking at adverse events reported in original 13 industry sponsored publications looking at rhBMP-2 use in spinal use representing 780 patients versus adverse events reported in subsequent publications and FDA data sets

Results

  • 13 original studies of BMP
  • All first authors had significant financial ties to Medtronic, the industry manufacturer of BMP
  • Meta-analysis of the 13 studies shows 0 complications associated with BMP
  • Review of subsequent studies, unpublished data from the original studies submitted to the FDA leads the authors to conclude that BMP has a true adverse event rate of 10-50%. Newer studies may also associate the product with a cancer risk
  • Dr. Carragee’s group proposes that the financial ties of the authors of the original 13 studies may help explain the lack of reported complications with BMP

Conclusion
Spine surgery is facing a real scandal with BMP. The association with cancer and the implication that financial considerations influenced the studies which led to its approval as a device by the FDA and to its widespread use is a big enough story that it has crept out of the pages of Spine and into the mainstream media. Reuters, the AP have both reported on it, as have major papers like the San Francisco Chronicle and the New York Times and the Wall Street Journal.

Infuse and other BMP based products are likely rightly dead and recalls are in the future. As for what this plays into the long going debate about the association between researchers and industry remains to be seen. But this is a big deal.

I’m going to be less than reactionary here. I think severing the ties between academic medicine and industry is impossible without hurting the common good. This country is the leader in advancing medical science partly because of funding from industry. I think the oversight is going to have to come from the academic institutions themselves. That’s a tough thing and there are major obstacles to people policing their colleagues. I’m not sure exactly what form that might take. But certainly I don’t think the government is not in a position to police it all. And the alternative is severing all ties to industry funded research.

Tuesday, September 20th 2011

Depression and Back Surgery

There are strong psychosocial components to pain syndromes. That isn’t a disparaging statement or a claim that pain is anything but real and each individual patient’s unique experience. But I feel that sometimes recognizing that major psychological component of pain and putting it into the decision algorithm for or against surgery is taboo.

The fact is you probably shouldn’t perform a back fusion surgery on a smoker for pain with instability. And its becoming clear that maybe you shouldn’t perform decompressive surgeries for pain on patients with poorly treated depression.

Strong independent associations were seen between depression burden (the sum of preoperative, 3-month and 6-month BDI scores) and 2-year disability, symptom severity, and poor walking capacity.

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Depressive symptoms interfere strongly with the ability of patients to obtain an optimal surgery outcome. Treatment models including the assessment and treatment of depression are encouraged.

This is a tough decision, you’re playing with the chicken and the egg here seeing as it is often a difficult assessment how much a patient’s pain syndrome is contributing to their mental health issues. But the fact is back surgery is major surgery with many, many serious risks and you should want the risk/benefit from the surgery to strongly favor the latter.

Wednesday, August 31st 2011

Too Much Care

Trying to define what is appropriate care and what is appropriate cost effective care is the long sought goal. Even the government has gotten into the business. The online Medicare Hospital Compare Quality of Care shows reported ‘quality’ metrics as reported by hospitals that participate in Medicare. One of the new statistics they’ve made available is the number of lumbar MRI scans health systems perform for back pain before conservative therapies are attempted for the back pain. Here is the write up on the NPR Shots Blog,

Back surgery is one of the best documented examples of expensive medical treatments that drive up health care costs while not always helping patients, and sometimes even hurting them.

And the latest Medicare data show that doctors frequently order MRI back scans for patients who haven’t tried recommended treatments such as physical therapy. An MRI often prompts surgery.

In 2009, 32 percent of Medicare patients with lower back pain who received a spine MRI at a hospital outpatient imaging center hadn’t tried a more conservative — and cheaper — treatment than surgery, according to data published on Medicare’s Hospital Compare website this month.

The point made at NPR is a little misplaced. I’m not sure we should blame MRIs for creating unnecessary surgeries. And that’s conceding much of spine surgery is unnecessary. If we want to reduce the use of ineffective spine surgery the idea isn’t to reduce the number of MRIs, its to educate and disincentivize ineffective spine surgery.

That aside it remains that I agree that lumbar MRI is an overused test. Since the vast majority of axial back pain does not respond to surgical or procedural intervention there is probably very little gained from most lumbar MRIs in terms of directing therapy. A course of conservative therapies for back pain is probably in order prior to any MRI. IF that fails, if radicular symptoms develop or if symptoms worsen then a lumbar MRI may be considered.

Despite saying that I contribute to the problem of MRI overuse.


Data From HHS At One of The Teaching Hospitals I’m At

At some of the teaching facilities I’m at I review a number of outpatient consult requests for back pain. I routinely refuse consults until MRI scans are available. This is because I’m looking for surgically amenable disease which is really the only issue, as the spine surgeon consultant, I can comment on. But I personally know the vast majority of the lumbar MRIs I review will not have surgically amenable disease. What I should really probably be saying on consults that come to me without MR imaging is that conservative therapy is in order prior to a reconsult with an MRI.

Friday, August 26th 2011

Nocioception In The Back

As recently as 2008 back pain was the number one reason patients visited emergency rooms in the United States. That is incredible to consider.

Chronic lumbar back pain is an incredibly difficult condition to treat often. In some because identifying pain generators in the back is difficult.

I had an interesting discussion and lecture today on the innervation of the lumbar vertebral column.

In very basic terms the anterior portion of the vertebral column and the posterior part of the intervertebral disc are innervated by the sinuvertebral nerves which are recurrent coming off the ventral rami at each level. These nerves form extensive anastamoses with the sympathetic trunk.

The posterior aspect of the vertebral column, including the facet joints, is innervated by lateral, inermediate and medial brances of the dorsal rami. These branches as well enjoy connections with the sympathetic trunk.

Lots more details exist obviously. The most interesting detail however may be that, at least in some animal studies, for all the sinuvertebral and lateral, intermediate and medial branches at all the levels they all eventually “return” through the L1 and L2 dorsal ventral rami.

That means that nocioceptors through a broad area are all returning the same. Is this signal coming from L4 or L1? It may help explain the visceral nature of much back pain and the difficulty in localizing the pain generator at times.

Or maybe I just don’t stand the implications of such. That’s always a possibility as well.

Wednesday, August 24th 2011

Urinary Incontinence With Back Pain

In my twenty six months in residency I’ve been called perhaps a couple dozen times by staff in the emergency room for suspected cauda equina. The usual cabal of symptoms are:

  • Back pain
  • Possible bilateral lower extremity radiating pain
  • Possible subjective weakness
  • Bowel and/or bladder incontinence

It is the last one that usually gets those physicians and physician extenders who are triaging the patients in the emergency astiring.

The cauda equina are the nerves that continue, after the end of the spinal cord, down to the legs and the sacrum. They provide for movement of the legs, urination, defecation, feeling to the legs and the perineal and “saddle” regions. Compression of these nerves, the majority of the time by a centrally herniated disc, is a neurosurgical emergency and known as cauda equina syndrome. Symptoms of cauda equina syndrome include: numbness or tingling to the inner thighs and perineum thought of as the “saddle” region, weakness especially a foot drop, inability to urinate or deficate, the opposite to include bowel or bladder incontinence, back pain.

Now, I’m sure I don’t get consulted with the vast majority of individuals who come into the emergency room with back pain. Even those individuals who have pain radiating from their back into their legs. But as soon as someone complains that they’re involuntarily urinating that seems to almost guarantee me a call.

Often times it seems that those triaging these patients seem to believe that involuntary urination or defecation has some high sensitivity for identifying patients suffering from cauda equina syndrome when combined with other symptoms as described above.

It turns out however that very few of these individuals have true neurogenic bowel or bladders.

In the perhaps two dozen of these patients I’ve seen I think two or three of them have had true cuada equina.

The question is then, if there is not something organic making these individuals urinate or defecate involuntarily then what is going on with the majority of patients I see who complain of such?

As one paper describes it, I truly believe there is an association between low back pain and urinary incontinence,

A rare association between severe low back pain and urgency incontinence of urine, not explained on the basis of any conventional neurologic or genito-urinary pathology, should be recognized.

For an unexplained reason there is a described association between pain and involuntary urination and defecation. And indeed, in my limited experience the vast majority of patients with both back pain and either bowel or bladder incontinence do not have neurogenic bowels or bladders or cauda equina syndrome.

Indeed, amongst these cabal of symptoms, urinary retention is likely much more sensitive a symptom for cauda equina pathology. With all the back pain that must be seen i the emergency room it’s probably an important point for staff to realize.