< The Study | The Blunders | The Results | The Discussion >

Duggal N, Dickman CA, et al. "Anterior Lumbar Interbody Fusion for Treatment of Failed Back Surgery Syndrome: An Outcome Analysis." Neurosurgery 2004; 54:636-644

DON'T BELIEVE EVERYTHING THAT YOU READ! I’m supposed to be taking some time-off, but after I received an e-mail claiming that a new investigation confirms that ALIF is the "wonder treatment" for failed spinal surgery, I had to take a brief hiatus from my sabbatical to set the record straight.

In this 2004 investigation that included a very well-known spinal surgeon as one of its authors the efficacy of Fusion surgery (ALIF) for the treatment of ‘Failed Back Surgery Syndrome’ was tested and confirmed.

The abstract, which is what my e-mailer alluded to, touted an almost unbelievable patient outcome at one year follow-up. More explicitly, the overwhelming majority of this small group of suffering patients "improved significantly" with respect to back pain (76%), leg pain (80%), and functional status (67%).

This outcome was far from the old adage that only 33% of patients achieve a satisfactory result to spinal fusion. So, I had to purchase it and see for myself (and the e-mailer) if the authors could really substantiate such claims.

Unfortunately, as I suspected, the study was seriously flawed in design (see below) and seemed terribly inconsistent. The biggest design flaw was the failure to use a standard and accepted outcome measuring device. Instead, the authors choose to used a outcome assessment system, unnamed, that was completely non-functional and almost comical; in fact, it was the most ridiculous method of assessing patient outcomes that I have ever seen! The biggest inconsistency was that despite the alleged amazing subjective improvement (how the patient reports to feel), O% of these now physically active patients were able to return to any form of gainful employment! Only the patients that were working before the operation (24%) were able to return to work. The authors did not address this inconsistency at all.

I want my spiny friends to know that reading abstracts alone can be very dangerous business and often 'spins the truth'! I sure hope this investigation hasn't prompted any 'fence-sitters' to jump down from their indecision onto the operating table in high hopes of achieving the touted near complete relief of chronic back and leg pain and the ability to have an "uncompromised" physical life. No surgery can offer an 80% guarantee, which was what seemed to be implied by the abstract of this investigation.

Although the authors admitted, on the last page, to some of the obvious downfalls of this investigation, and even went as far as saying "It is possible that our results overestimate the potential benefit of anterior lumbar interbody fusion for failed back surgery syndrome...", their failure to disclose this information in the abstract, which is always freely available to the general public on-line (www.pubmed.com), really bothered me... hence this review.

The Study:

Thirty-three patients, all of whom had suffered a past failed spinal surgery and were diagnosed with Failed Back Surgery Syndrome (FBSS), were gathered for this investigation and re-operated on by the senior surgeon, the famous Dr. Curtis A. Dickman. Before surgery the group was examined, radiographically assessed and made to fill out two subjective assessment tools.

Very stringent entry criteria were used: among other things, any patient having signs of chronic neuropathic pain, i.e., allodynia, causalgia, hyperalgesia, or PTH (progressive tactile hypersensitivity) were excluded from the investigation; furthermore, any patients found to have recurrent disc herniation, and/or stenosis were also excluded. This was a very, very, select group of patients. The exclusion of the stenotic group was particularly puzzling to me, since this group is often treatment with decompressive fusion.

Three sub-groups were then formed: the Degenerative Disc Disease group, the Postsurgical Spondylolisthesis group, and the Pseudoarthrosis (failure to fuse) group.

All patients underwent an ‘Anterior Lumbar Interbody Fusion’ by the senior author, Dr. Dickman. In this style of fusion, all the delicate posterior neural structures are not disturbed, for they approach the spine from the front - through the belly.

The Assessment Tools: The root of this investigations woes.

The most important part of any investigation is the method by which the patient improvement, or lack of improvement, is measured. Some of my favorite methods for assessing the efficacy of a procedure are simple but unforgiving: 1) Has the procedure allowed the patient to return to work, 2) Has the procedure gotten the patient off medication, 3) Would the patient choose to have the procedure again knowing how he feels now, and 4) How much has the patients Oswestry and VAS improved as a result of the procedure. With the latter criteria, there are no "games" that can be played with the investigations result; it's pretty much black & white.

The biggest design problem of this investigation, aside from the small study cohort (33 patients), and the relatively short follow-up period (one year), was the method used for assessing the pre-surgery and post-surgery level of patient pain and disability. Amazingly, either the 'Oswestry Disability Index' nor the 'Visual Analog Scale' were used in this investigation. (I've got a page on these 'gold standards' HERE) Instead, the team used the lamest and most bizarre outcome assessment tools I have ever seen. These name-less assessment tools, simply called "assessment forms", required the patient to select one of five categories that would categorized their level of pain. These categories, especially the category for assessing the level of patient pain, were completely inadequate and completely ruined this investigation. The assessment forms used in this investigation have so many inconsistencies and stupidisms (my word) I’m hesitant to even mention them, but here it are:

Rating:	Functional Disability Definition:
#1	Functions at previous levels without restriction. Independent in leisure activities and activities of daily living. Walks unlimited distances. Independent in wheelchair activity with paraplegia.
#2	Mild limitations of function, with some restrictions. Mildly limited in leisure activities and activities of daily living. Walks five to six blocks. Dependent in some aspects of wheelchair activity with paraplegia.
#3	Moderate limitations of function but employable. Moderately limited in leisure activities and activities of daily living. Walks three to four blocks. Moderately dependent in wheelchair activity with paraplegia.
#4	Severe limitations of function, unemployable. Severely limited in leisure activities and activities of daily living. Walks one to two blocks. Severely dependent in wheelchair activity with paraplegia.
#5	Invalid or bedridden because of spine. Walks less than one block.

Rating:	Pain Definition:
#1	None: no pain or patient ignores pain
#2	Slight: occasional pain, no compromise in activity.
#3	Mild: no effect on ordinary activities, rarely moderate pain with unusual activities, may take aspirin.
#4	Moderate: pain tolerable, but patient makes concessions to pain; some limitations of ordinary activities or work; may require occasional pain medication other than aspirin.
#5	Severe: pain sufficient to cause serious limitations of activities; chronic or frequent use of prescription pain medications.

On the functional disability assessment tool, note that the description for a near total disability (category 4) is the ability to walk only one to two block. This is where most of the patients were categorized prior to surgery. In order to be considered a "success" in this outcome study, the patient had to move down two categories. Note that a category 2, which is where most of the patients ended up one year after surgery, was described as "being able to walk 5 or 6 blocks! That's barely any walking improvement at all, yet was considered a success! You mean to tell me that the ability to walk 5 to 6 blocks, which isn't even a single mile, is considered a success and a very low level disability! You see my problem with this tool.

The Pain assessment tool has so many inconsistencies I'm not even going describe them all... it's simply a terrible assessment tool! For example, on a scale of 0 to 10, my daily level of pain is usually about a '2'. This would be considered a very low level of pain and is confirmed by the fact that I 'rarely' need any medication. However, on the authors pain assessment tool, my level of Pain is not allowed to be a low level. Because of it's definitions, my pain would be considered a category 4, which is the second highest pain level, for I certainly have "some limitations of ordinary activities and work" and "make concessions to pain". Do you get my point now! These assessment tools are completely inadequate!

The Results: Seems to good to be True.

Leg Pain: According to the researchers, 94% of the patients had level 4 or 5 leg pain prior to surgery. The result of the surgery, at one year, is this: “More than 80% of patients achieved our definition of successful outcomes…[with respect to leg pain] ”. Although the investigators failed to give the exact numbers, it appears that 82% achieved an UNBELIEVABLE RESULT, in that they recovered to the point of having "no compromise in activities" and only had "occasional pain" in the leg ( level 2 of lower)! Apparently they could do anything they wanted: swim, play tennis, hike, bike, etc! UNBELIEVABLE. Where do I sign up! More explicitly, 15% of the patients improved to the #2 level (Slight: occasional pain, no compromise in activities.), and 67% of the patients had NO leg pain or were able to completely ignore the leg pain. So, 82% of the patients basically completely recovered from their post-surgical leg pain.!

Back Pain: Yet another amazing result! 76% of the cohort (patient group) recovered at least to the point of having "no compromise in activities" and only had "occasional pain" in the back (level 2 of lower)!

Functional Outcome: The functional outcome, although still unbelievable in my book, was not nearly as spectacular: 67% of the patients obtained a “successful” outcome, i.e., 22 of the 33 patient improved from a category #4 to a category #2. This means that the patient could go from walking only 1 or 2 blocks to a 5 or 6 blocks. NOT very impressive in my book... 8 blocks is a mile, so they still can't even walk a mile yet they were deemed a success. (I'm playing the devils advocate here)

Employment: Ah, they did ad one of my favorite assessment categories; one that is very unforgiving in terms of proving the efficacy of a tested procedure: Unfortunately, 0% of the patients who had been unable to work prior to the surgery were able to return to any form of work. How can that be! Supposedly, 82% of the cohort recovered from their leg pain and 76% recovered from their low back pain but yet none could return to work? Granted some of these patients had no motivation to return to work, i.e., retired and collecting disability, but this result still raises a 'red-flag' in my book.

There was also a 11% complication rate: One torn small iliac vein that resulted in an 800 ml blood loss and forced the patient into a transfusion; one attack of atrial fibrillation, one development of respiratory insufficiency, and two Interbody cage displacements.

In all fairness to these researchers, they did fess-up to the inadequacies of this investigation, but not in the abstract. They stated the following: “It is possible that our results overestimate the potential benefit of ALIF for FBSS because of the subjective nature of the selection process, the small sample size, and the relatively short follow-up period.”

Discussion:

The only reason I have even bothered to posted this investigation is to demonstrate how DANGEROUS it can be to only read 'investigation abstracts'. Since most layperson's will not pay $20.00 for a full version of an investigation paper, the whole truth of an outcome may go unlearned. I believe it is the responsibility of the authors to include any data compromising factors within the abstract, in order to avoid the distribution of false and misleading information to the public.

In this investigation Dickman and company touted that fusion, from the anterior approach, offered a statistically very favorable alternative to suffering with significant chronic back and leg pain, i.e. there is an 80% chance that you will have a "favorable" outcome, you will have "no compromise to activities" and you will suffer only have "occasional pain" following a fusion from the anterior approach.

Unfortunately, their investigation was fatally flawed by the outcome instruments that were used (discussed above); the only viable outcome measure, in my opinion, was the number of patients who recovered enough to be able to return to some form of work. That number, 0%, completely flew in the face of the touted 80% success rate and demonstrated that Fusion treatment for Failed Back Surgery Syndrome is certainly no panacea.

I have learned the hard way that there is no 'magic bullet' for killing off chronic back and leg pain. Fusion surgery is a risk and should ONLY be performed as a last ditch effort. I'm afraid 'mother nature' and 'grandfather time' are all us chronic pain sufferers have going for us at the time of this writing (11/28/04). Don't get me wrong, fusion has it place for the treatment for chronic back and leg pain, and it occasionally (33% of the time) can indeed yield a wonderful outcome... but the numbers touted in this investigation were absolutely ridiculous!

I guess, since it's now 3:00 AM, I took issue with this investigations failure to disclose potentially deceiving information within its abstract. I also can't imagine why standard outcome tools weren't used; what a waste this study was! I just hope some poor layperson doesn't read this abstract and let it push him into trying a surgery when maybe he shouldn't have.

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