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Do you all still do 2 diagnostic facet blocks before RFA even with 90-100% relief from 1st block. What do you do if the second is less than 50% relief.
Diagnostic facets blocks
- Thread starter galenao
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nope. never have.
but i almost always do intra-articular injections first, so if they want "two blocks" i count the IAs as one, although i dont really feel like it is. and i wouldnt go to RF with just an IA injection.
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I do diagnostic blocks--single-blind, double anesthetic paradigm.
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Cervical & thoracic I do IA and if they don't get long acting relief I go to RF. Lumbar I do MBBs and then RF. In younger patients I'll do IA lumbar before RF if the patient requests it but the older the patient the less likely it will work. Over 60 I won't even offer lumbar IA.
I only do double blocks if the insurance company requires it. I consider it a waste of time.
I only do double blocks if the insurance company requires it. I consider it a waste of time.
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Lets just skip the argument and RF everyone at the first go-round. If it works we're done with it, if it doesn't work, we move on.
What's the rub on just burning these nerves?
No charcot spine, no long term adverse sequellae.
For the love of multifidus, let's just burn the darn things.
What's the rub on just burning these nerves?
No charcot spine, no long term adverse sequellae.
For the love of multifidus, let's just burn the darn things.
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In most pts over 60, I don't think it is really possible to do true IA facets. At best you are doing peri-articular.
When the axial view across the facets looks like the Dodge Ram symbol, the needle ain't gettin' in.
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Nothing a Stineman pen and a rasp can't handle.
But that would bill as a fusion and not an MBB.
(Tru-fuse for those who don't get the joke).
completely disagree...
the more i do, easier it is to get in virtually any facet joint. I also think the older than 60 often do quite well if IAs. I often dont RF many older people as they do quite well for quite a long time with IAs
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Fun procedure looking for an indication.
I'd love to do it, just can't yet figure out why.
im in pmr4msk's camp. IA injections are unreliable in the old folks, IMHO. also, the literature for IA injections is no where near as strong as MBBs/RFs. ill take that over anecdotal evidence.
i feel the same way... i just cant find a patient that meets the "criteria"
the guys down the road have become a "center of excellence" for this...
im a big supporter of evidence. But when my experience is telling me something different, it is hard to stop doing something that is highly effective because someone says it isnt. maybe in their hands it isnt effective. I do a lot of RF, but i could do tons more of it, if i dint do IA first on people... I am actually trying to save patients from procedures, and often it works, quite a bit of the time. not always. I guess whatever works for you, as long as it works...
thats fair enough. i like to save my IA injections for the younger crowd, rather than the older crowd to try to avoid RF on younge patients. if it works, it works, and im sure that there are people on this board who do the procedures differently (?better?) than others.
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I still find that doing peri-articular/IA facets still works in the elderly, but find that more often than not, the needle cannot get into the joint, but remains peri-articular. I find it still helps often to inject peri-articular when I can't get in. I cannot defend the mechanism.
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you are covering the capsule with the anesthetic, which kuslich showed to be the prime pain generator of the z-joint.
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reference please? I'm interested.
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its old skool...orthospine guy did surgery without GET but instead did it all under local. found pain generators to be the outer annulus and facet capsule. i will give exact reference tomorrow.
Ortho Clinics of N.A., April 1991. p. 181-7. Stephen Kuslich, et. al. The Tissue Origin of Low Back Pain and Sciatica. A report of pain response to tissue stimulation during operations on the lumbar spine using local anesthesia.
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I agree that peri-articular can help. I have had to follow up so many times with RF though that in the older folks I go straight to RF. Nonethless periarticular is a good diagnostic block that indicates you're on the right track, and the positive response encourages the patient to keep trying.
The recent work by Bogduk and Dreyfuss suggest that periarticular injection in the SI joint might give similar information.
The recent work by Bogduk and Dreyfuss suggest that periarticular injection in the SI joint might give similar information.
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The ability of multi-site, multi-depth sacral lateral branch blocks to anesthetize the sacroiliac joint complex.
Dreyfuss P, Henning T, Malladi N, Goldstein B, Bogduk N.
Pain Med. 2009 May-Jun;10(4):679-88
OBJECTIVE: To determine the physiologic effectiveness of multi-site, multi-depth sacral lateral branch injections.
DESIGN: Double-blind, randomized, placebo-controlled study.
SETTING: Outpatient pain management center.
PATIENTS: Twenty asymptomatic volunteers.
BACKGROUND: The dorsal innervation to the sacroiliac joint (SIJ) is from the L5 dorsal ramus and the S1-3 lateral branches. Multi-site, multi-depth lateral branch blocks were developed to compensate for the complex regional anatomy that limited the effectiveness of single-site, single-depth lateral branch injections.
INTERVENTIONS: Bilateral multi-site, multi-depth lateral branch green dye injections and subsequent dissection on two cadavers revealed a 91% accuracy with this technique. Session 1: 20 asymptomatic subjects had a 25-g spinal needle probe their interosseous (IO) and dorsal sacroiliac (DSI) ligaments. The inferior dorsal SIJ was entered and capsular distension with contrast medium was performed. Discomfort had to occur with each provocation maneuver and a contained arthrogram was necessary to continue in the study. Session 2: 1 week later; computer randomized, double-blind multi-site, multi-depth lateral branch blocks injections were performed. Ten subjects received active (bupivicaine 0.75%) and 10 subjects received sham (normal saline) multi-site, multi-depth lateral branch injections. Thirty minutes later, provocation testing was repeated with identical methodology used in session 1.
OUTCOME MEASURES: Presence or absence of pain for ligamentous probing and SIJ capsular distension.
RESULTS: Seventy percent of the active group had an insensate IO and DSI ligaments, and inferior dorsal SIJ vs 0-10% of the sham group. Twenty percent of the active vs 10% of the sham group did not feel repeat capsular distension. Six of seven subjects (86%) retained the ability to feel repeat capsular distension despite an insensate dorsal SIJ complex.
CONCLUSION: Multi-site, multi-depth lateral branch blocks are physiologically effective at a rate of 70%. Multi-site, multi-depth lateral branch blocks do not effectively block the intra-articular portion of the SIJ. There is physiological evidence that the intra-articular portion of the SIJ is innervated from both ventral and dorsal sources. Comparative multi-site, multi-depth lateral branch blocks should be considered a potentially valuable tool to diagnose extra-articular SIJ pain and determine if lateral branch radiofrequency neurotomy may assist one with SIJ pain.
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Abuse?
It would save 64475x2, 64476 x6 (L3-S1, 2 separate occasions).
I think that is close to $2k off the bill.
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I just went directly to left L3-L5 medial branch neurotomy for a 49yo terminal esophageal cancer patient. I wanted to get him treated asap so he could enjoy his remaining time. Any thoughts on skipping diagnostic MBBs in such a case?
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Sounds like a perfectly reasonable exception to the general rule, IMHO. Very different than advocating that we change the rules altogether.
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THey are not rules, they are guidelines, and not really guidelines at that.
What do they call them again?
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As this thread reflects, people have a lot of trouble following guidelines that don't match up with what they see with their own eyes.
If the guidelines say you have to do double blocks but your second block always confirms the first block (or you find that you get good results with just one set of MBBs) you start to wonder if the data are valid, and hence the guidelines from which they are derived become questionable.
A lot of people, ISIS instructors included, do not follow ISIS guidelines. This is one of the frustrations that the ISIS standards committee faces on a regular basis in its courses. The instructors themselves deviate from The Book and teach other approaches, whereas the goal of the ISIS course is to teach ISIS standards.
It would be great to practice based on evidence but most of our evidence is not all that good and it is appropriate to question EBM. Pain is not like hypertension where you have a discrete objective measurement. In addition, as also seen in this thread and many others, we can't even agree on what constitutes "relief".
Most studies use pain scales, which are hopelessly flawed for so many reasons I won't try to enumerate them right now. Those of you who have the ISIS CD from the 2008 meeting can look at my slides for the arguments.
In addition, a study that just relies on pain scales easily misses what we do not miss in the clinic - an opportunity to see WHY a pain scale might still be elevated. We all know that patients can not reliably differentiate pain generators. An RF of L5/S1 might "fail" in a study because the design did not include examining the patient to see why they still perceived back pain.
You can successfully denervate painful facets but have a patient return complaining the procedure "failed" because their back still hurts, only to find another pain problem. I see this a lot in patients with spinal stenosis. They have both a neurogenic and a somatic problem that is diffusely localized over the low back. You can treat one successfully but until the other is addressed they will consider the treatment a failure.
Having said all that, I have often wondered if we couldn't do a good job of RF in one session. I usually do my MBBs by first marking the skin over the tender levels and then anesthetizing what's underneath, then re-examining them while still on the table. Maybe I could just RF what's underneath the markers and see what happens. If they get up from the table without pain at least I know my local anesthetic worked and hopefully the burns worked too.
The downside is that if you are wrong and the axial pain is not facet then you've RF'd for nothing. OTOH, what is the downside? It's a safe procedure with minimal side effects and whatever you did would be reversed in about a year.
The upside, of course, is fewer days missed from work, lower facility expenditures, and fewer procedures (hmm, gotta think about that - rechargeable batteries killed a rather lucrative IPG replacement market 😉).
Ultimately there needs to be a head-to-head study of MBB -> RF vs straight-to-RF to resolve this, both in terms of efficacy and - just as important in today's environment - cost savings.
If the guidelines say you have to do double blocks but your second block always confirms the first block (or you find that you get good results with just one set of MBBs) you start to wonder if the data are valid, and hence the guidelines from which they are derived become questionable.
A lot of people, ISIS instructors included, do not follow ISIS guidelines. This is one of the frustrations that the ISIS standards committee faces on a regular basis in its courses. The instructors themselves deviate from The Book and teach other approaches, whereas the goal of the ISIS course is to teach ISIS standards.
It would be great to practice based on evidence but most of our evidence is not all that good and it is appropriate to question EBM. Pain is not like hypertension where you have a discrete objective measurement. In addition, as also seen in this thread and many others, we can't even agree on what constitutes "relief".
Most studies use pain scales, which are hopelessly flawed for so many reasons I won't try to enumerate them right now. Those of you who have the ISIS CD from the 2008 meeting can look at my slides for the arguments.
In addition, a study that just relies on pain scales easily misses what we do not miss in the clinic - an opportunity to see WHY a pain scale might still be elevated. We all know that patients can not reliably differentiate pain generators. An RF of L5/S1 might "fail" in a study because the design did not include examining the patient to see why they still perceived back pain.
You can successfully denervate painful facets but have a patient return complaining the procedure "failed" because their back still hurts, only to find another pain problem. I see this a lot in patients with spinal stenosis. They have both a neurogenic and a somatic problem that is diffusely localized over the low back. You can treat one successfully but until the other is addressed they will consider the treatment a failure.
Having said all that, I have often wondered if we couldn't do a good job of RF in one session. I usually do my MBBs by first marking the skin over the tender levels and then anesthetizing what's underneath, then re-examining them while still on the table. Maybe I could just RF what's underneath the markers and see what happens. If they get up from the table without pain at least I know my local anesthetic worked and hopefully the burns worked too.
The downside is that if you are wrong and the axial pain is not facet then you've RF'd for nothing. OTOH, what is the downside? It's a safe procedure with minimal side effects and whatever you did would be reversed in about a year.
The upside, of course, is fewer days missed from work, lower facility expenditures, and fewer procedures (hmm, gotta think about that - rechargeable batteries killed a rather lucrative IPG replacement market 😉).
Ultimately there needs to be a head-to-head study of MBB -> RF vs straight-to-RF to resolve this, both in terms of efficacy and - just as important in today's environment - cost savings.
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You do have to rush with these folks if your oncologists are like the ones in my area. It seems like I usually get called about 5 days before death, when the patient is so snowed that they want me to "do something" so the patient can be awake and pain free for his last few days. Quite often they are dead before I can even get precert.
So if you have cancer and you see me walk into the room for a consult, you should not put on any long-playing records. 🙄
in a case like that, you could do the "modified gorback approach". bring them in, do the mbbs, examine in 15 minutes, and then do the RF the same day if they get relief. might not get paid for both, but it would save them an RF if there is no response to the blocks.
amen. lets use judgement. i wouldnt want my mother treated with only algorithm. We assess each patient and make the appropriate recommendation for that patient. Guidlines help to make these decisions. But we are not technicians. that just follow some over-regimented pathway, when they evidence is not absolute.
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Remember the good ole S.A.T. analogies:
0.5 ml lidocaine is to a lumbar medial branch as 10 ml lidocaine is to .....
the median nerve in the carpal tunnel
(volume equivalency)
25 g spinal needle is to a lumbar medial branch as 12 g trocar is to....
the median nerve in the carpal tunnel
(size equivalency)
0.5 ml lidocaine via 25 g needle is to a lumbar mbb as 10 ml via a 12 g trocar is to... the median nerve in the carpal tunnel
(procedure equivalency)
so....if the probability distribution of a carpal tunnel injection with a 12 g trocar and 10 ml of lidocaine causing neurolysis, transient neuropraxia, or plain ole nerve block....is x,y,z percent....
then the probability distribution of a lumbar mbb with a 25g needle and 0.5 ml lidocaine causing neurolysis, transient neuropraxia, or plain ole nerve block...is x,y,z percent
recently Dr. Manchikanti in Spine demonstrated 15 weeks of relief with cervical mbb with local only.....
so it is conceivable that the ISIS guidelines are actually advocating a double diagnostic neurolytic protocol before actually going on to the third 'RFA' neurolysis
0.5 ml lidocaine is to a lumbar medial branch as 10 ml lidocaine is to .....
the median nerve in the carpal tunnel
(volume equivalency)
25 g spinal needle is to a lumbar medial branch as 12 g trocar is to....
the median nerve in the carpal tunnel
(size equivalency)
0.5 ml lidocaine via 25 g needle is to a lumbar mbb as 10 ml via a 12 g trocar is to... the median nerve in the carpal tunnel
(procedure equivalency)
so....if the probability distribution of a carpal tunnel injection with a 12 g trocar and 10 ml of lidocaine causing neurolysis, transient neuropraxia, or plain ole nerve block....is x,y,z percent....
then the probability distribution of a lumbar mbb with a 25g needle and 0.5 ml lidocaine causing neurolysis, transient neuropraxia, or plain ole nerve block...is x,y,z percent
recently Dr. Manchikanti in Spine demonstrated 15 weeks of relief with cervical mbb with local only.....
so it is conceivable that the ISIS guidelines are actually advocating a double diagnostic neurolytic protocol before actually going on to the third 'RFA' neurolysis
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The real importance of Manchikanti's MBB work is that if you expect a patient to be able to tell the difference between a long-acting LA and a short-acting LA you are sadly misguided, since the effect can far outlast the local anesthetic action.
I can't reproduce Manchikanti's results in terms of either duration or percentages. I have only seen a week or two of pain relief after MBBs and only in the occasional patient (and I do a lot of facet work since the median age of my patient population is "Pleistocene").
The spinal cord is to the medial branch as a fire hydrant is to my . . um . . . let's pick a different analogy. Whatever the relative size of the cord vs the MB, assuming 100:1 for purposes of discussion (i.e., I was too lazy to look it up) then 10 ccs injected around a MB is a lot different than, say, 1,000 ccs injected into the spinal canal. The former is a big trigger point injection and will have little or no sequelae, whereas the latter is an epiduroscopy and the wide range of neurological effects that have attended the procedure.
A pressure injury to a nerve should cause a certain number of patients to develop neuralgia after MBB. Who is hearing those sorts of complaints from their patients?
I can't reproduce Manchikanti's results in terms of either duration or percentages. I have only seen a week or two of pain relief after MBBs and only in the occasional patient (and I do a lot of facet work since the median age of my patient population is "Pleistocene").
The spinal cord is to the medial branch as a fire hydrant is to my . . um . . . let's pick a different analogy. Whatever the relative size of the cord vs the MB, assuming 100:1 for purposes of discussion (i.e., I was too lazy to look it up) then 10 ccs injected around a MB is a lot different than, say, 1,000 ccs injected into the spinal canal. The former is a big trigger point injection and will have little or no sequelae, whereas the latter is an epiduroscopy and the wide range of neurological effects that have attended the procedure.
A pressure injury to a nerve should cause a certain number of patients to develop neuralgia after MBB. Who is hearing those sorts of complaints from their patients?
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Hi Mike,
Your post exactly supports my contention with the ISIS guidelines.
I have long been a critic of the double local anesthetic diagnostic paradigm.
Even one to weeks of relief following a local mbb injection would be considered an outlier for the isis guidelines---in their model, lidocaine should only last 1-2 hours and bupivacaine 4-8 hours....the fact that you had patients have a blockade for 1-2 weeks is by definition a neuropraxic event and not a local anesthetic event. I personally haven't seen 15 weeks, but like you, I have seen 1-2 weeks.
Local anesthetics are known to cause myotoxicity and have been responsible for transient radicular irritation (when pooling around nerves). Hence they can cause neuropraxia by pressure or concentration of local anesthetic.
So when your diagnostic paradigm relies on a patient reporting pain relief that is consistent withthe duration of the local anesthetic....you are going to get many outliers that will develop neuropraxia (numbness or pain relief for several days...until the nerve regenerates at 1 mm/day....). Similarly, with mbb, what do you do when you have someone get 1 week of relief? Is this placebo or neuropraxia. If it is the latter, then does that mean that rfa will also result in only 1-2 weeks of relief.
The relative sizes of volume and needle to mbb was to illustrate that you would never use a 12 g trocar with 10 ml local for a carpal tunnel injection--you would get numbness that would persist beyond the duration of local anesthetic. If you used such a technique to diagnose carpal tunnel syndrome (double diagnostic carpal tunnel injections), you would arrive at a false diagnosis and you would damage the nerve.
Since the prevalence of facet mediated pain is so high and risk of injury following rfa so low....it seems there is greater risk/benefit ratio in doing one procedure (rfa) vs. doing three(rfa+mbb)
As far as pressure along the nerve..this may cause numbness and not pain--hence you don't see persistent neuralgia....howeever, I have seen a post procedural flare up of pain after the local wears off and before the steroids fully kick in...
Overall, I believe the double diagnostic paradigm continues have many problems--and this is just one of the difficulties.
Your post exactly supports my contention with the ISIS guidelines.
I have long been a critic of the double local anesthetic diagnostic paradigm.
Even one to weeks of relief following a local mbb injection would be considered an outlier for the isis guidelines---in their model, lidocaine should only last 1-2 hours and bupivacaine 4-8 hours....the fact that you had patients have a blockade for 1-2 weeks is by definition a neuropraxic event and not a local anesthetic event. I personally haven't seen 15 weeks, but like you, I have seen 1-2 weeks.
Local anesthetics are known to cause myotoxicity and have been responsible for transient radicular irritation (when pooling around nerves). Hence they can cause neuropraxia by pressure or concentration of local anesthetic.
So when your diagnostic paradigm relies on a patient reporting pain relief that is consistent withthe duration of the local anesthetic....you are going to get many outliers that will develop neuropraxia (numbness or pain relief for several days...until the nerve regenerates at 1 mm/day....). Similarly, with mbb, what do you do when you have someone get 1 week of relief? Is this placebo or neuropraxia. If it is the latter, then does that mean that rfa will also result in only 1-2 weeks of relief.
The relative sizes of volume and needle to mbb was to illustrate that you would never use a 12 g trocar with 10 ml local for a carpal tunnel injection--you would get numbness that would persist beyond the duration of local anesthetic. If you used such a technique to diagnose carpal tunnel syndrome (double diagnostic carpal tunnel injections), you would arrive at a false diagnosis and you would damage the nerve.
Since the prevalence of facet mediated pain is so high and risk of injury following rfa so low....it seems there is greater risk/benefit ratio in doing one procedure (rfa) vs. doing three(rfa+mbb)
As far as pressure along the nerve..this may cause numbness and not pain--hence you don't see persistent neuralgia....howeever, I have seen a post procedural flare up of pain after the local wears off and before the steroids fully kick in...
Overall, I believe the double diagnostic paradigm continues have many problems--and this is just one of the difficulties.
Dr. Shah, correct me if I am wrong, but you seem to be suggesting that the long duration of analgesia after a MBB is secondary to a demyelination (neurapraxia) rather than the actions of the LA. Thus, the physical pressure around the MBB would cause the sustained pain relief (or a second mechanism of local toxicity). I have a difficult time swallowing this. If this were the case, we should see similar prolonged analgesia with a simple saline injection as well.
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Before Manchikanti's papers came out in The Journal of Positive Results I just figured that maybe I had broken up a pain-spasm cycle for a while with the LA.
What would be the best way to test this neuropraxis theory? Maybe a long skinny flathead screwdriver applied at the SAP/transverse process and then give a few taps with a hammer?
What would be the best way to test this neuropraxis theory? Maybe a long skinny flathead screwdriver applied at the SAP/transverse process and then give a few taps with a hammer?
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Part 1. Get an ASC so you can benefit from the party.
Part 2. Call it a mallet and bill for more $$$.
Lobel's Paradigm: straight to RF with good long term relief.
Lobel's Paradox: straight to RF with no long term relief.
Either way we cut costs and cut nerves.
I'm going to position myself at the table with insurance and push for this as well as limiting spine procedures to a limited number of taxonomy providers.
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I don't know about you, but I find that, anytime a surgeon does his own discography, he has a much higher rate of positive studies than when he sends them to an objective third party. (I am pretty sure there is good literature to back this up, but I cant find it with a cursory Medline search).
Part of why ISIS demands a double block is BECAUSE we are doing our own diagnostic study in preparation for a longer-lasting therapeutic intervention. It denies us the opportunity to bias our results quite so much. None of us think were are biased, but all of us think surgeons are - so maybe we aren't as unbiased as we think.
Part of why ISIS demands a double block is BECAUSE we are doing our own diagnostic study in preparation for a longer-lasting therapeutic intervention. It denies us the opportunity to bias our results quite so much. None of us think were are biased, but all of us think surgeons are - so maybe we aren't as unbiased as we think.
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Which branches do you RF? Most of us use MBBs to focus our attention on the relevant levels. Not everyone needs L2-L5 fried. The Lobel method leads to far less precision, and increased cost due to excessive lumber of levels being addressed unnecessarily.
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I don't see how the second block makes us less biased than with the first block. Is there any evidence that bias extinguishes with repetition? If so, how many repetitions do you need to remove 95% of the bias? Two seems to be pretty arbitrary. Who came up with two, and what was the scientific basis for that conclusion?
The discussion of cervical MBBs in the ISIS book is interesting. They cite Barnsley's paper where "a large proportion of patients who responded to an initial block failed to respond to a subsequent block. A diagnosis based on a single block, therefore, could not be relied upon to secure a correct diagnosis."
The logical fallacy of course is the assumption that the negative block is always the valid one - a truism with no scientific foundation.
In the next paragraph they cite Lord's paper from 1995 and conclude that double blocks have a sensitivity of 54% and a specificity of 88%. In other words, this paradigm misses the diagnosis roughly half the time. To me, these results show that (to paraphrase ISIS), "A diagnosis based on double blocks, therefore, could not be relied upon to secure a correct diagnosis either".
One might be tempted to speculate that whoever wrote this chapter was biased toward double blocks. And they spell "lidocaine" wrong. 😀
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Lignocaine is Australian for lidocaine 😉
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It was a joke Peter.
They use a lot of funny words like "pethidine" and "zygapophysial joint".
They use a lot of funny words like "pethidine" and "zygapophysial joint".
all of the UK and its commonwealth(s) use "lignocaine"
its my favorite medication, but nobody knows what it is when i ask for it...
not abuse....abuse is charging for all of these facet injections when you already know the answer..RF is not a dangerous procedure in skilled hands....
Even though the academic types will highly disagree with what I am going to say, I will say it anyway. I routinely do IA facet for lumbar and MBB for cervical/thoracic. If successful short term, perform RFA. If sucessful longterm (over 8 months), repeat previous. Recently pulled charts on 150 RFA patients. Success rate (defined as greater than 50% relief and improvement of function for at least 6-9 months) is 95.3% (143/150). Complications 0%. You guys can dispute this but I really don't see any reason to put these patients through all of these unnecessary procedures when the answer is already known. This approach is saving the system money....
I do not find this to be the case. More and more spine surgeons are becoming very conservative about operating (especially in a smaller jurisdiction). Likewise you should not be performing RF in a situation with an unsatisfactory diagnostic block..You may gain in the short term as you collect more dollars, but ultimately an unhappy patient will not benefit you...
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can you publish this?
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The value of the MBB in the setting of previously + response to IASI is that it can weed out those who are getting a more generalized/systemic steroid response.
What we need, as others have stated before, is to do the MBB, then ablate everyone, and then see which ones the MBB predicted to respond positively. + and - predictive value can then be calculated.
Your data suggests 95% probability of RFA been effective after a + response to IASI. My anecdotal evidence is liely lower.
What we need, as others have stated before, is to do the MBB, then ablate everyone, and then see which ones the MBB predicted to respond positively. + and - predictive value can then be calculated.
Your data suggests 95% probability of RFA been effective after a + response to IASI. My anecdotal evidence is liely lower.
it actually surprised me as well but it is what it is.....the reason that I actually pulled those charts were to elicit the help of these patients in writing a letter to noridian (i instructed my assistant to pull the last 150 RF's)...As I reviewed them, i realized that the success rate was so high..
