S1 dorsal ramus contribution to L5/S1 facet pain?

[Ligament]

Is there a definitive statement on whether the S1 dorsal ramus contributes significantly to the L5/S1 facet?

Are you blocking S1 dorsal ramus for L5/S1 z-joint arthralgia?

Also, anybody here doing post RFA needle EMG of the multifidi to confirm good burns, and how does reimbursement for such an EMG work?

Thanks

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[lobelsteve]

Is there a definitive statement on whether the S1 dorsal ramus contributes significantly to the L5/S1 facet?

Are you blocking S1 dorsal ramus for L5/S1 z-joint arthralgia?

Thanks

The motion segment is L4-5 and L5-S1. I block L3-S1 and then RF those levels if the double diagnostic blocks tell me to do so.

Never heard of EMG afterwards, but you would then need EMG of the paraspinals beforehand to note a change in the study. Gratuitous and unnecessary- unless you offered it as a free service to check your work.

 

[ampaphb]

The motion segment is L4-5 and L5-S1. I block L3-S1 and then RF those levels if the double diagnostic blocks tell me to do so.

Why, if the patient is painful directly over one joint, is there any reason to address any other joint? To me, extending your focus to a "motion segment" is unjustifiable when you can pinpoint a pain generator with z-joint inflamation on MRI and localization of the point of maximal tenderness under fluoro.

 

[lobelsteve]

Why, if the patient is painful directly over one joint, is there any reason to address any other joint? To me, extending your focus to a "motion segment" is unjustifiable when you can pinpoint a pain generator with z-joint inflamation on MRI and localization of the point of maximal tenderness under fluoro.

I used to think the exact same thing. Patients proved me wrong.
Also a dentist proved me wrong. I went in last year with need for root canal and a crown. I also mentioned that there was pain in the bottom molars as well as the worse pain in the top. The dental assistant said she thought it was referred pain- I said I was a pain physician and did not think this was so. The dentist said it was referred pain and proved it by providing an inferior alveolar block, then he hit me with cold spray on the top. It still hurt in my lower jaw, but much worse up top.

I do not believe that pushing on skin 3" above a joint is exactly pinpointing the problem. Much like my anecdote above has no applicability to CLBP. But it makes sense to me. Now if we could get funding for a SPECT controlled DBRCT with MBB to joint you choose with finger on skin, vs motion segment (turn off the bottom 2 joints regardless (unless it clearly is upper lumbar or lower thoracic spine), followed by RF when needed- then we would have something to talk about. Oh the studies are there for the taking these days. Yet nobody wants to take the time to do them....

 

[Tenesma]

i agree with AMPA that we shouldn't be frying 3 joints...

on the other hand, I disagree that it can be easily figured out with an MRI and/or Physical exam... because it ain't easy...

i have seen patients with a completely destroyed L3/L4 joint from moderate scoliosis - they had relief from an L5/S1 TF (despite the fact that L5/S1 looked intact on MR)...

the issue really revolves around patience... who of us is interested in doing diagnostic mBB up and down the spine until we find the single joint that is responsible... not to mention that anecdotally, i find that it is rare to get relief with turning off only one joint, and tend to see better relief with denervating 2 joints.

 

[Ligament]

i agree with AMPA

This is officially the end of the internet!

 

[Ligament]

The motion segment is L4-5 and L5-S1. I block L3-S1 and then RF those levels if the double diagnostic blocks tell me to do so.

Never heard of EMG afterwards, but you would then need EMG of the paraspinals beforehand to note a change in the study. Gratuitous and unnecessary- unless you offered it as a free service to check your work.

Ok, so you do block the S1 dorsal ramus, but by chance are you aware of the literature supporting or refuting this? I know Dreyfuss did a study blocking the L4 medial branch and L5 dorsal ramus and then found provocation arthrography with saline at the L5/S1 facet joint was no longer painful in most patients, however some patients still had pain. Some have concluded that since such a high percentage got facet anesthesia that the S1 dorsal ramus is insignificant. However, one could infer the other way that the small percentage of failures (I think it was 11%) were failures since the S1 dorsal ramus was not blocked.

I believe that EMG of the multifidi has been reported in the literature to confirm MBB destruction. I think an interesting study would be to EMG the paraspinals of non-responders after lumbar RF and see if MB destruction truly occurred at that level (has this already been done? I seem to recall some similar study). Of course, you'd have to use Fluoro to guide the EMG needle to the appropriate level...I'm always shocked how some people do paraspinal mapping blindly without image guidance.

Addendum:

Paz had posted this study a while ago, thanks paz!

Dreyfuss P, Halbrook B, Pauza K, Joshi A, McLarty J, Bogduk N.
Efficacy and validity of radiofrequency neurotomy for chronic lumbar zygapophysial joint pain.
Spine. 2000 May 15;25(10):1270-7.
PMID: 10806505

STUDY DESIGN: A prospective audit. OBJECTIVE: To establish the efficacy of lumbar medial branch neurotomy under optimum conditions. SUMMARY OF BACKGROUND DATA: Previous reports of the efficacy of lumbar medial branch neurotomy have been confounded by poor patient selection, inaccurate surgical technique, and inadequate assessment of outcome. METHODS: Fifteen patients with chronic low back pain whose pain was relieved by controlled, diagnostic medial branch blocks of the lumbar zygapophysial joints, underwent lumbar medial branch neurotomy. Before surgery, all were evaluated by visual analog scale and a variety of validated measures of pain, disability, and treatment satisfaction. Electromyography of the multifidus muscle was performed before and after surgery to ensure accuracy of the neurotomy. All outcome measures were repeated at 6 weeks, and 3, 6, and 12 months after surgery. RESULTS: Some 60% of the patients obtained at least 90% relief of pain at 12 months, and 87% obtained at least 60% relief. Relief was associated with denervation of the multifidus in those segments in which the medial branches had been coagulated. Prelesion electrical stimulation of the medial branch nerve with measurement of impedance was not associated with outcome. CONCLUSIONS: Lumbar medial branch neurotomy is an effective means of reducing pain in patients carefully selected on the basis of controlled diagnostic blocks. Adequate coagulation of the target nerves can be achieved by carefully placing the electrode in correct position as judged radiologically. Electrical stimulation before lesioning is superfluous in assuring correct placement of the electrode.

 

[ampaphb]

i have seen patients with a completely destroyed L3/L4 joint from moderate scoliosis - they had relief from an L5/S1 TF (despite the fact that L5/S1 looked intact on MR)

Facet imflamation is a bit different

Pain Med 2008 May-Jun;9(4):400-6
Fat-saturated MR imaging in the detection of inflammatory facet arthropathy (facet synovitis) in the lumbar spine
Czervionke LF, Fenton DS.

OBJECTIVE: The objectives of the study were: to illustrate the magnetic resonance (MR) imaging appearance of facet synovitis in the lumbar region using an MR fat-saturation technique; to determine how commonly facet synovitis is encountered when fat-saturation techniques are used; to classify the MR appearance of facet synovitis; and to test the correlation between the location of a lesion and the site of the patient's pain.

DESIGN: In total, 209 consecutive MR studies of the lumbar spine were retrospectively reviewed to document the prevalence of lumbar facet synovitis in daily imaging practice. The degree of facet synovitis was graded. Medical records of 30 additional symptomatic patients with MR evidence of unilateral, single-level facet synovitis were reviewed to determine the side of the patient's clinical symptoms.

RESULTS: Facet synovitis occurred in 41% of lumbar MR studies reviewed. No patient reviewed had evidence of active infection. Most often, signal changes were restricted to the affected joint. The side of the facet synovitis correlated with the side of the patient's clinical symptoms.

CONCLUSION: Facet synovitis is a common condition and appears to correlate with the patient's pain. Detection of active inflammatory facet osteoarthropathy (facet synovitis) within and surrounding the facet joints is possible with MR imaging using a fat-saturation technique.

 

[drusso]

I do it Steve's way. Here's why: Most patients are poor sensory discriminators. Also, there's no rule that says that you can't have two things wrong with you. Unless there is a clear history of trauma (ie I fell on back and landed right *HERE* and it's hurt ever since) we're dealing with degenerative spondylosis.

Following the motion segment approach outlined by Steve offers the best statistical chance of hitting the mark. Now, if they're *CLEARLY* tender and provocative at the thoracolumbar junction, I don't bother anesthetizing the lower lower lumbar motion segments. You get the idea.

 

[Tenesma]

you are lucky my local rad guys do Fat-sats only in Sagittal... and sag. sucks compared to axial (or even thin-slice coronal) to see the joints.

and i have seen it look many different ways - i have had perfectly normal looking joints respond beautifully to MBB/RF... i have had horrible looking joints not respond whatsoever - and because of my belief they were the source of pain, got a SPECT that was quiescent...

i have come to learn to rely more and more on thin-slice CT (coronal and axial) for posterior element pain because the pictures are just better and tend to make more sense compared to exam and MBB blocks...

i'll talk to my rads guys...

 

[Mister Mxyzptlk]

I do not believe that pushing on skin 3" above a joint is exactly pinpointing the problem.

I agree with this. The pressure is diffused through the various layers (and IMHO, people with only 3" to push through are getting more and more scarce), and the nervous system can't discriminate that well in the spine.

I will usually do the level directly under the point of maximum tenderness and the adjacent levels above and below. In the case of L5/S1 I only do the joint above. Sometimes I'll do MBBs one level
at a time with repeat poking in the spine while still on the table to see if the pain has been addressed. The trouble is, sometimes it's ok on the table and then there is pain when they get up, so I've sort of evolved into painting with a broad brush.

What I struggle with is doing levels that might not be a problem but getting good coverage vs having false negatives by doing too few and having the patient complain it "didn't work" or having to bring them back for another day of missed work, full facility fee costs, etc to do another joint. I guess it boils down to whether you want sensitivity or specificity with the procedure.

To address the root post, I haven't bothered with the S1 branch for about 10 years and I don't miss it. Never considered postop EMG. As far as I'm concerned if the pain stops, the nerves were burned.

 

[ampaphb]

As far as I'm concerned if the pain stops, the nerves were burned.

Yes, but if the pain doesn't stop, was it an inadequate lesion? Or is there an additional pain generator you have not yet addressed?

 

[Mister Mxyzptlk]

The original question was whether you should get a postop EMG to confirm your burns. If the pain is gone, I don't need a confirmatory EMG.

As for your question, I can settle that infrequent issue easily enough with medial branch blocks. I don't need an EMG.

 

[drusso]

The original question was whether you should get a postop EMG to confirm your burns. If the pain is gone, I don't need a confirmatory EMG.

As for your question, I can settle that infrequent issue easily enough with medial branch blocks. I don't need an EMG.

Also, it would be difficult for an EMG to distinguish between active denervation or simple membrane instability from local tissue trauma from the cannulae. It's like checking paraspinals in patients with a history of fusion--you're going to see EMG changes.

 

[Mister Mxyzptlk]

I think it would be interesting if someone with an EMG machine could try using multifidus EMG monitoring instead of paresthesia stim. Would the signal from the motor stim interfere with the EMG?

If this worked you could conceivably do RF under general. Cumbersome perhaps, but preferable to the patient who reports paresthesias in his arm every time the cuff goes up.

 

[SSdoc33]

I think it would be interesting if someone with an EMG machine could try using multifidus EMG monitoring instead of paresthesia stim. Would the signal from the motor stim interfere with the EMG?

If this worked you could conceivably do RF under general. Cumbersome perhaps, but preferable to the patient who reports paresthesias in his arm every time the cuff goes up.

i dont think that would work. you wouldnt see EMG changes until at least a week after the burn. you could look for loss of voluntary motor units in the paraspinals, but that wouldnt be possible under general. also, id be worried about frying a big nerve if they were out completely.

i GUESS there would be a benefit for clear-cut facetogenic pain in a younger person with a "virgin back" to confirm denervation. It would be a little difficult to tell the exact level, however, if you denervated more than one joint

 

[lobelsteve]

i dont think that would work. you wouldnt see EMG changes until at least a week after the burn. you could look for loss of voluntary motor units in the paraspinals, but that wouldnt be possible under general. also, id be worried about frying a big nerve if they were out completely.

i GUESS there would be a benefit for clear-cut facetogenic pain in a younger person with a "virgin back" to confirm denervation. It would be a little difficult to tell the exact level, however, if you denervated more than one joint

He means the signal crossing over to the EMG machine causing interference when in the multifidus and not in any other muscle or tissue. Similar to the interference seen on EKG monitor during stimulation and lesioning with the RF.

I guess we could test this by putting an EMG machine in the fluoro suite and seeing what causes interference. I am guessing that the EMG needle will pick up no matter where in the body the RF probe is sitting.