Research, the numbers, your doctor, and YOU (the patient)

[laid up doc]

I responded to a thread where many people were saying that their cervical prodisc surgery didn't give them the relief they were looking for. i got off on a few tangents, which really deserve their own threads. here's my dedicated thread to one of those tangents...

as my name implies, i am a doc - an MD in another specialty that sees a wide variety of medical issues. i am not an orthopedist or neurosurgeon. i will not comment further on my personal specifics b/c i would rather preserve my anonymity on the net.

as such, here is my attempt at a primer in research, the numbers, your doctor, and YOU, the patient.

On how doctors make decisions: one course in medical school at most US schools is on "evidence based medicine", or EBM. this, very simplified, is the use of a given study to guide your decision making. the best original research papers are "randomized control trials", or RCT's, where patients are assigned to a treatment and results are compared. some treatments are amenable to an RCT, whereas others are not.

if there is a "gold standard", or widely accepted best treatment, for a given disease, then a new treatment is compared to it. lacking a gold standard (i'll call it GS for short from here on out), an RCT may compare a treatment to placebo - which can be no treatment or a sham treatment. some diseases have a GS diagnostic test - for example noncontrast CT scan to diagnose kidney stones, while others don't or there is debate about whether there is a GS. a GS can change over time - for the same example, another test called IVP (intravenous pyelogram) was the GS for kidney stones until a good study came out saying that noncontrast CT had many advantages over IVP and was as good or better at making the same diagnosis. sometimes it is difficult and/or impossible to establish a GS - for example, if it is a rare disease, or a disease w/ limited options where an RCT can't be done. many, many cancer treatments lack good evidence for this reason.

From what i have read, there is no accepted gold standard "workup" for evaluating pts for disc pathology and symptomatology. many docs believe that a discogram is a GS test - but there are camps of docs out there who disagree (Eugene Carragee out of Stanford being the main one).

to further apply this principle to back pain - as far as evaluating the "success" of surgery/role of any given disc or surgery -- if one does not properly identify pain generators and exclude non-discogenic sources of pain, ensure that the level that is being operated on is the sole pain generator... basically not do a thorough workup - then a level is picked to "fix" and may not be the right level, not be inclusive enough, or may not even be the source of the pt's symptoms. since there's no GS workup... who does or doesn't get a particular surgery, or artificial disc, or experimental biologic - is determined by your doctor.

basically, there is such a thing as "drift" in indication - basically when something comes out, dr's sometimes offer the new tx, even if not the right one, to the wrong pt, and then the tx is blamed. many ppl think that this led to the demise of IDET. this is often due to the following limitation of EBM...

in order for the study to apply to YOUR PATIENT, one has to consider the STUDY DESIGN. you must look at the inclusion/exclusion criteria, study population, and various statistical constructs that a researcher may use to warp statistics... among other things. this is beyond the ability of many patients, which is really unfortunate. one is left to trust what a given MD tells them, and ALL dr's have SOME sort of bias, based on where they trained, their personality, tolerance of risk, personal experience, their patient demographics, etc etc.

another thing you must consider is the OUTCOMES of a given study - what should you expect after surgery? pain reduction? returning to work? less narc use? all of these things can be end points, but depending on the study, they are defined differently, measured differently, and the stats used to analyze the data are different.

i'll stop for now. i hope that this somewhat long-winded intro helps some of you in your decision making. i have tried to explain things as simply as i can, but feel free to ask me clarifying questions. i will do my best to answer, but as i always do when making medical commentary - i'm not a spine dr and i'm not your dr. i will tend to answer in generalities rather than specifics. i won't do anything that could be construed as being anyone's physician, b/c that's not legal and i'd be risking my license if i treated someone w/o the appropriate licensing in their state/country/whatever. as i have stuck my neck out a bit, i have de-personalized my avatar and signature accordingly.

i will add that despite my own training and research into back pain/ADR/fusion etc etc, i have not reached a conclusion as to what procedure i myself will have... partly b/c i have extensively reviewed what i can, and need to resolve whether i have a contraindication to ADR, and partly b/c i don't think there's a clear answer whether ADR or fusion is better at my involved level. no one can ever make a guarantee or predict an outcome absolutely, but one can arm oneself w/ all of the information one can prior to making a decision.

[Slackwater]

Thanks for writing it down above. Agree.

VAS, ODI, narcotics level, ... are subjective, or qualitative.

I try to joke about having a digital read-out that does not exist.

The Gold-Standard - Fusion was reached partially by a prospective RCT in Sweden (?). It was compared to no operation, no-treatment. The same author(s) (? Fritzell P, Hägg O ?) report on ADR/TDR recently from their experience with their National Spine Registry (link1 2001 Volvo Award, link2, link3 ADR v. Fusion, link4). I do not have ready availability of all their conference postings from over the years on Fusion and ADR.

The "evidence" on ADR is limited to 5 or 10 years at most. The evidence on Fusion (ALIF, TLIF, 360, ...) is in the decades, though still short in quality by some researcher's standards.


The "Gold Standard Fusion" re-operation rate is a measurable factor. The Fusion re-op rate, as documented by Mirza, Deyo et al in Washington, was high enough to make me look around. More later, the todo list has too many open items. To date, my limited recall is the re-operation rate and narcotics use by ADR/TDR patients is lower than Fusion.

[laid up doc]

i tell patients all the time that i don't have a meter for their pain... VAS to me is sort of useless as is the 0-10 scale that JCAHO makes us use. to me, it's more along the lines of 1. bad enough for pain meds, 2. not, or a. disrupting your life or b. not. but again, i work in a different field of medicine.