Dr. Lipetz Responds to Recent Spinal Stenosis Articles

For our patients, their families, and our colleagues, Dr. Jason S. Lipetz comments on the recent New England Journal of Medicine and New York Times articles on the role of spinal injections in the treatment of spinal stenosis.

Summary of Comments: 

  • The findings of this study do not correlate with those of our practice or the clinical experience of respected colleagues nationally.
  • The findings of this study must not be translated as relevant to all forms of spinal stenosis.
  • Many different injection approaches were performed in this study, most of which were not in a state of the art, transforaminal fashion which is a more exact epidural injection.
  • It is not clear how the spinal level of injection was determined in each case or who interpreted the MRIs or CT scans prior to injection.
  • Several different types of steroids were utilized in this study, with some doses quite low, some extremely high, and in some cases the steroid utilized is known to be less likely to result in a satisfactory response after one or two injections.
  • The steroid group in this study began with greater degrees of disability and duration of pain.  The outcomes actually do show real benefit for the steroid group by several measures, but these were discounted by the authors.
  • The control group medication in this study is suspected to be a poor choice, as the medication and volume injected in this group may have its own therapeutic effect.
  • Finally, the potential for study bias when a government agency sponsors a study which is examining Medicare spending is discussed.

The recently publicized findings of the study from the New England Journal which have been debated in the media are concerning to the physiatrists of Long Island Spine Rehabilitation Medicine (LISRM) and our respected colleagues nationally.  For the average reader and public at large, the intended take home message from this study is that epidural steroid injections do not offer meaningful relief from lower limb pain arising from spinal stenosis.

This conclusion contradicts our own clinical experience and that of our colleagues. In addition, several previous studies have demonstrated the success of epidural injections in the treatment of radicular pain.  In our practice, we continue to advise patients that epidural steroid injections more often than not do offer a component of relief from leg greater than back pain arising from stenosis.  Most often, when benefit is realized, relief does last for at least six weeks.  Sometimes, relief is realized for months or years, and in some cases surgery is avoided all together.  Our surgical colleagues often describe similar experiences with patients’ responses to judiciously utilized epidural injection therapy.

In our practice, epidural injections are utilized in a highly selective fashion by fellowship trained interventional spine and musculoskeletal physiatrists with years of clinical experience and  board certifications in pain medicine and electrodiagnostic medicine.  Injections are only selected as an appropriate treatment approach following a thorough history and detailed spine specific physical examination performed on each patient along with a personal and meticulous review of all spinal images (MRI or CT).  At LISRM, injections are almost universally performed in a selective nerve root transforaminal fashion and with state of the art imaging techniques.

While we must always applaud the efforts of our colleagues for their contributions to meaningful research, we must also be critical of every manuscript, no matter if the findings are favorable or contradictory to our own clinical experience.  Ultimately, the burden is upon all of us to demonstrate the efficacy of our treatments through well designed studies.  The recent New England Journal article is concerning in terms of its methodology and conclusions on several levels, and these concerns will be reviewed below.

First, this study’s findings must not be translated to the treatment of all stenosis presentations.  In this regard, the title is most misleading.  Stenosis may affect the spinal nerves in a variety of anatomic and lateralizing forms, and this article reportedly deals specifically with isolated central stenosis.  In addition, central stenosis may arise in multiple ways.  This may result from a disc herniation or multifaceted degenerative findings, but the origin of stenosis in this study is also not clarified.  It is also unclear what severity of stenosis was treated.  It is stated that the stenosis observed in each case was graded from mild to severe, but the relationship between severity of stenosis and clinical outcomes is never further mentioned in the report.  It should also be highlighted that patients will often present with spinal stenosis on film, but this may not represent the origin of their leg pain.  The manuscript in this case does not account for how such clinical presentations may have been clarified and excluded.

There was no uniformity of treatment in this study.  Rather, 26 different physicians at 16 different locations treated these 400 patients.  It is stated that the treating physicians were “trained” by the study investigators to administer injections in a standardized fashion using fluoroscopic guidance.  This comment raises potential concern with regard to the level of experience of some of the treating clinicians in this study.  In addition, the question arises as to which study investigators were providing this training.  Of the lead authors in this study, it does not appear that any specialize specifically in non-surgical interventional spine medicine.

In this study, is stated that the level of injection was selected in some instances by the level of stenosis on film and in others by the symptomatic nerve root level.  It is not clarified if the treating interventionalists in this study ever examined the films themselves prior to injection or how the clinical determination of the symptomatic nerve root was made. Was this through pain distribution alone? Dermatomal pain patterns may often mislead through symptom overlap.  Was an examination performed to assess for more subtle examination findings, such as a reflex or motor asymmetry, which might better confirm a level of segmental pathology?  It would not appear that electrodiagnostics or selective nerve root diagnostic injections were utilized, as is at times clinically necessary, to confirm a symptomatic nerve root level. Some of the treating physicians in this case are suggested to practice in environments where patients are treated in accordance with the orders of their colleagues rather than after a meticulous film review and thorough neurological and musculoskeletal examination which they themselves perform.

The steroids utilized in this study were also not standardized nor were the dosages administered.  In our opinion, the steroid dose described in this study likely ranged from the potentially low therapeutic to the ill advised extreme.  In addition, recent studies have demonstrated that the use of dexamethasone, also included in this study, may result in a higher likelihood of patients requiring a third injection to achieve a desired therapeutic effect.  This is yet another consideration in this study in which only one to two injections were performed.   This study also focuses on the adverse systemic effects of corticosteroid administration.  It should be highlighted that in our practice the dose and choice of steroid are tailored to each patient and clinical presentation.  This practice, along with the monitoring of patient response and consultation with the patient’s concurrently treating specialists when indicated prior to injection, has resulted in a minimal adverse response occurrence among our patients.

In this study, more than 70% of all injections were performed in an interlaminar fashion, and it is not clear that contrast enhancement was utilized with each injection.  Interlaminar injections administer medications to the dorsal aspect or back of the spine rather than directly along the path of the suspected symptomatic nerve root.  Interlaminar injections are for several reasons recognized as anatomically inexact when compared with transforaminal injections and are not endorsed as a primary injection approach by leading interdisciplinary spine societies.  The evidence supporting the efficacy of transforaminal injections in the treatment of radicular pain is also superior to that for interlaminar injections.  In our practice, the treatment of leg pain arising from symptomatic stenosis is almost exclusively performed with a fluoroscopically guided, transforaminal injection approach.

The patients included in the steroid group in this study began treatment with a greater duration of pain and greater level of disability than the lidocaine alone group.  While not highlighted by the authors, when adjusted to account for these differences, a statistically significant difference in treatment response in terms of disability was realized by the steroid group.  In addition, across both treatment measures, improvements at three and six weeks were greater for the steroid group than for the lidocaine group, but these were determined not to be clinically and statistically significant.  Significant advantages were also realized in the steroid group vs. the control at three weeks, but symptom response at three weeks was not chosen as a primary outcome measure.  In addition, the lack of uniformity of treatment in this study was mirrored in the means of outcome data recording.  Despite the extrapolation that perhaps only 15 patients were treated on average at each treatment center, standardized means of data collection was not enforced.  Rather, such data was collected by the researchers by either telephone, personal interview, or a mailed questionnaire.  This raises real and additional concern in this study with regard to uniformity of understanding and the consistency of reporting by each patient. The authors’ attention to statistical and power analysis in this study is not matched by an equal attempt to provide standardized and best evidence based care or data collection.

This study also chose to use lidocaine as a control group rather than a placebo injection of contrast alone, a low volume of saline, or no medication introduction at all.  This raises further concern with regard to whether the control group injectate was actually inert.  Several basic science studies have previously demonstrated the potential anti-inflammatory effects of local anesthetic, in this case administered in considerable volume.  Recent review articles in the spine literature have suggested that such properties of lidocaine along with the potential therapeutic benefit of neural lavage from higher volumes of injectate make this a poor choice of control injection in such clinical outcome studies.  Despite this knowledge, a high volume of anesthetic was selected as a control injection by the authors of this study.  Indeed, in this study, both groups of patients demonstrated levels of relief which would appear to surpass that expected from placebo effect alone.

Finally, and unfortunately, the consumer of the medical literature must always be sensitive to investigator bias, either intentional or subconscious, which might impact data reporting and study results.  Typically, concerns arise when studies are funded by device or medication manufactures, as these studies have historically been demonstrated to report more favorably in terms of treatment effects.  In this case, the authors, publishing in a primary medical rather than dedicated spine journal, make a clear point that there was no commercial influence or funding in their study. But isn’t it only fair for us to consider all potential extraneous influences as critical readers of research?  This study was funded by a government agency, the Agency for Healthcare Research and Quality.  The authors’ introduction to this study highlights the dollars spent by Medicare, another well known government agency, on spinal injections.  While device manufacturers and pharmaceutical companies are in the business of making money through providing healthcare products, services, and innovations, Medicare and the government are in the business of not spending money on physician services.  Each year, Medicare pays physicians less and less for the same service regardless of the level of support from the literature for the care they provide.  If Medicare observes the practice of a particular service or procedure to grow beyond an expected rate over a period of time, the result is often a draconian reduction in reimbursement for all providers performing this procedure rather than a more judicious process to reward those truly practicing evidence based medicine and penalizing those who do not.  It is only fair to have this discussion in terms of potential bias of this study and its relationship to the government and the payer, in this case the Medicare system.  Medicare is an unsustainable and flawed system which stays afloat by annually devaluing healthcare services, particularly those performed in greater volume, rather than incentivizing the performance of true evidence based medicine, encouraging innovation, and allowing patient choice and real market forces to play a role in controlling costs.

We as spine specialists have the responsibility to provide the most evidence based, cost effective, and compassionate care, while doing no harm, to each patient we encounter.  When utilized properly, and as described, epidural steroid injections with corticosteroid remain an important and often effective treatment option for our stenosis patients debilitated by leg pain who are either not yet appropriate candidates for or who are unwilling or unable to proceed with spinal surgery.