Carragee EC et al. 2009 ISSLS Prize Winner: Does Discography Cause Accelerated Progression of Degeneration Changes in the Lumbar Disc: A 10-Year Matched Cohort Study
In 2009, Carragee et al publisher results of their award-winning study which tested the hypothesis that the “disc needlestick” which occurs normally as part of the discography procedure would not have any deleterious (damaging) long-term sequelae (effects) on that disc. Specifically, they wanted to know whether or not the needlestick would increase the chances of de novo (new) disc herniation and/or accelerated degenerative disc disease, like it does in animals.
What’s the bottom line? Discography, no matter what size needle was used, significantly (p<0.05) increased the rate of accelerated degenerative disc disease and new disc herniation, compared to discs that were not stabbed with the discography needle. These findings were actually double confirmed! Keep reading and I will explain below.
METHOD:
Out of a large pool of patients who all had similar diagnoses (i.e., previous symptomatic cervical degenerative disc disease, lumbar disc herniation or somatization disorder), two matched groups of patients were created based on their willingness to undergo provocative discography. Specifically, a discography group (n=75) was created, which was composed of patients who were willing to undergo provocative discography (discography) of the L3, L4, and L5 discs. Then, a control group (n=75) was created with condition-match patients who were not willing to undergo discography. Both groups were willing to be followed and periodically reevaluated for the next 10 years.
After the groups were created, all 150 patients underwent an MRI of the lumbar spine, as well as standard radiographs. These MRIs were evaluated by two board-certified radiologists and any disagreements between those radiologists were settled by a third radiologist who was only used as a tiebreaker. The patients also completed a self-disability assessment test (the classic Oswestry Disability Index test), the results of which were reported in another paper.
10 YEAR REEVALUATION:
At the 10-year time point, 80.3% of the study group and 74% of the control group were successfully contacted. After the interview, patients were eliminated from the study if it was discovered that they had suffered any type of interval trauma, infection, surgery, or pathology to their lumbar spine, which of course could have con founded the results. Remember, the only disc injury we are studying is the needlestick injury, so other disc injuries had to be excluded.
After the follow-up exclusion criteria was applied, 52 (69%) subjects were left in the study group and 50 (67%) subjects were left in the control group. Next, new MRIs were performed on most of the remaining group members and reevaluated by the same radiologists. If the patient had happened to have an MRI that was less than three years old, this was used.
RESULTS
With regard to the discs that suffered a needlestick injury during discography (i.e., the L3, L4 and L5 discs of the discography group), there were 55 de novo (new) disc herniations, compared to only 22 new disc herniations in the control group. This difference was very statistically significant: p=0.00003, which is way past the normal statistical threshold of p<0.05! In other words, there is almost no doubt that needlestick injury to the disc increases the chance for de novo herniation.
The discography group also suffered a statistically significant increase in the chance for the development of Modic change (a severe form of degeneration of the disc and vertebral endplate) (p=0.04), which is known to be associated with increased frequency of severe disabling low back pain [Maatta-2014].
The discography group also suffered increased degenerative disc disease (p=0.03) at the needlestick levels, with associated discopathy (disc height loss) (p=0.05).
Furthermore, with regard to the location of the herniations, they typically occurred on the same side and in the vicinity of the original needlestick injury. (p=0.0006).
As a confirmation, they also looked at the L1 and L2 discs of patients only in the discography group. Recall that these two discs were not stuck with the discography needle. Lo and behold, when comparing these two levels with the control group, there was no significant difference between the groups. This confirms that it was the actual needlestick injury to the disc that was causing all the degenerative sequelae.
And finally, they looked at the actual needle size. Some discographers used a 22 gauge (bigger) needle while others use to 25 gauge (smaller) needle. The thought was that the smaller gauge needle would cause less negative sequelae, but it did not. There was no statistically significant difference between the different sized needles, which matches animal studies.
AUTHOR’S CONCLUSION
The author stated, disc puncture with even a small gauge needle and limited injection pressures appears to be associated with accelerated disc degenerative processes that include disc herniation, loss of the disc height, loss of disc signal (DDD) and the development of reactive endplate changes (Modic change).
“We believe careful consideration of risk and benefit should be used [when] recommending procedures involving disc puncture for diagnostic or therapeutic purposes….”
DR. GILLARD’S COMMENTS
Now it's important to understand that not all of the needle-stuck discs in the study suffered significant pathological degeneration and its sequelae (i.e., Modic change, disc herniation, etc.), for some of them were unchanged, even after 10 years, so the question is, do you feel lucky? [No Clint Eastwood pun intended] According to this study, the odds are against you, for the needlestick disc injury significantly increases the chance of big trouble for that disc. So why take the chance?
I’ve been warning my coaching clients about the dangers of needlestick injury since 2002! The animal research of the 1990s clearly demonstrated that even the tiniest of pricks of the intervertebral disc almost universally doom it to degenerative disc disease (black disc) and the development of a full thickness annular tear and even herniation in some cases. I knew it would only be a matter of time before research would finally prove what seemed so logical to me and others.
Carragee et al. also raised another potential sequelae of discography and fusion outcomes. The phenomenon of adjacent segment disease following interbody fusion (i.e., the Domino effect) may be significantly enhanced if the fusion patient had previously underwent provocative discography. Somebody must do this study as soon as possible. Because it is common practice for a pre-fusion patient to undergo provocative discography which demands that a control disc (one above and/or below the fusion level) be punctured and tested.
I will bet you anything that if someone does a study they will find that patients who underwent provocative discography have a higher rate of adjacent segment disease than those who didn’t. It’s another perfectly logical conclusion which may take another decade or so to be proven by research.
I have decided not to wait, for I stopped recommending that a control disc be used to confirm a concordantly painful disc. Instead, I am recommending that the injectionist use a disc anesthetic to double confirm the concordantly painful disc, which I have learned that many discography practitioners fail to do, which they really should! But now they better.
Another fantastic study produced by Eugene Carragee, M.D., orthopedic surgeon, who is the head of Stanford’s orthopedic spine surgery department.