We're gonna talk about image guided blocks for pain syndromes. The goals of these blocks are often to reduce narcotic requirements, manage acute pain crises, and what we've learned is that the autonomic nervous system contributes significantly to many pain syndromes.
We'll talk about some neuro blocks, neurolysis, and nerve ablations. When we talk about neurolysis and nerve ablations, what we're trying to do rather than a block which is just a temporary fix and control of pain, we now wanna try to make it at least semi-permanent
to give that patient some time to allow them to ramp down their narcotics, maybe have an improved quality of life. The agents that we use for neurolysis are alcohol and phenol, but more recently, we're starting to use both thermal ablation,
pulsed RF ablation, and cryoablation.
We've talked a little bit or touched on some of the traditional blocks, Demetrius has kind of run through some of those, so I won't be covering those. But the concept is that basically you put your needle
in the space, you inject a little contrast to make sure you're in a safe position and then you give a combination of lidocaine and a longer acting agent like bupivacaine with a steroid and then that's the block. Once you've done that and diagnosed that that's actually
addressed the problem and is addressing the pain, you can then move on to the neurolysis and ablation where you're sort of more permanently blocking that. We started incorporating some of the more complex sympathetic blocks into our practice which really, many of the pain specialists out there
shy away from because they're much more heavily reliant on imaging and that's where we shine, and that's where you all come in to help us to use the guidance techniques that William talked about to sort of get us to some of these more difficult places to reach.
This is a super busy diagram, but basically this looks at both the somatic nerves and the autonomic system. I don't think we have a laser, unfortunately. Basically the autonomic system innervates the liver, the gallbladder, the stomach, and the upper epigastrium,
but also innervates the large and small intestine. And then as we move down from top to bottom into the lower sympathetic chain, there's innervation of the kidneys, of the uterus, ovaries, scrotum, the urinary bladder, and the perineum. So, in thinking about it that way,
we then can understand where we're gonna target our blocks based on where the pain syndrome is.
The stellate ganglion is one of the higher blocks and it's actually probably one of the more difficult blocks. Many of the pain specialists will do these blind which I think is kind of amazing,
considering you have the vertebral artery, you have the carotid artery, you have the esophagus in the vicinity, and so this is a block that I think should definitely be done under image guidance. There have been papers showing that when done under CT guidance, that there's a much greater accuracy
and success with this block. The stellate ganglion block is used to treat complex regional pain syndromes in the upper extremities, like reflex sympathetic dystrophy, hyperhidrosis. So if you have patients who have heavy sweating in the hands, you can use this block to address that.
It's also been used for refractory angina, which I thought was interesting. Phantom limb pain in patients that have had amputations of their upper extremity. Herpes zoster, as well as pain in the head and neck. This block also is used in Raynaud's syndrome
in a scleroderma, it's used in vasospasm syndromes, in patients that are post traumatic or have experienced frost bite, or have embolic syndromes in the upper extremity. And again, intractable angina is one that I actually learned when I was reading about this talk.
One of the indications that is not well known is the use of the stellate ganglion block for hot flashes in the setting of breast cancer. Many of these patients are on tamoxifen and other types of agents that can cause intense hot flashes and a stellate ganglion block can actually
improve those symptoms.
This is the technique under CT guidance. This was an actual patient who had chronic pain in the left shoulder with arm pain. This diagnostic block is to determine whether there is a sympathetic component.
You bring your needle down, avoiding the carotid and sometimes you do have to pass through the jugular vein, but that's okay because you're using a small needle. And then as we're getting closer to the spine at the T1 level you also have to avoid the vertebral artery. So we bring the needle down and we basically dock the needle
just lateral to the esophagus at the junction between the rib head and the T1 vertebral body and that's exactly where the stellate ganglion lives. We inject a little contrast to make sure that we're not intervascular, and then the lidocaine and bupivacaine mixture.
Patients often get immediate relief on the table. This patient did well with this block. We've had several patients that have undergone this block for hot flashes and have had improvement in their symptoms. We've had some failures, but this is one that is not often offered and can really help
in some of these complex pain patients.
The celiac plexus block is one that is much better known and I think you probably have all experienced this in your practices, but the celiac plexus block and neurolysis is for the treatment of intractable epigastric pain, most often in pancreatic cancer,
but it can also be in patients who have liver masses or have biliary dilatation and have biliary tubes placed and are having pain related to their biliary tree. But it's also used for intractable nausea and vomiting. If you have somebody who has profound nausea and vomiting and is not responding to normal medications,
a celiac plexus block and neurolysis can improve that. The permanent block blocks the sympathetics and allows the parasympathetic system to start working unopposed, so it actually can improve gastric emptying, which is why we think it improves the nausea and vomiting.
It can improve GI motility, so it can actually improve patients' appetite. The only sort of danger to this block and neurolysis is that it can cause diarrhea by having that parasympathetic system working in overdrive without the sympathetics to balance,
that you can actually develop diarrhea.
This is where the celiac plexus lives, so it's around the celiac artery, usually just slightly above, but is actually a mantle of nerve tissue that is from the celiac down to the SMA. You can see on the image on the right,
we've approached from the posterior paraspinous approach and we're using a curved needle where we basically dock the base needle which is a 22 gauge needle adjacent to the aorta and then we take a 25 gauge needle that's curved and bring it anterior to the aorta and that's where we can eject the contrast.
You can see the contrast now layering just anterior to the aorta, hopefully not in the aorta. But the beauty is, you're using a 25 gauge needle, so you really can't do much harm. Once you've injected the contrast, the lidocaine and bupivacaine, you can then either move directly
to giving the neurolytic which is absolute alcohol, usually about 15 to 20 CCs, or you can use phenol, which is more commonly used in Europe. This basically denatures the myelin, destroys the myelin sheath, and stops the conduction of those nerve fibers.
This particular patient had significant improvement, did have some diarrhea, but demonstrated significant improvement after that block. This is an actual patient that we treated several years ago. 55 year old woman, she was very cathectic. She was in the end stages of her life
and she had pancreatic cancer. She had an abdominal wall met that was actually invading into her liver and she had severe epigastric pain and constipation. Her ECOG status was poor and she was on a lot of narcotic medications.
She had one of these metastases resected and her pain had come back immediately. You can see just anterior to the liver, there's this soft tissue mass that's invading into the liver. She has multiple liver metastases and her pancreatic cancer
is invading into her celiac plexus. So using a combination of what Nick has talked about and these nerve blocks, as an interventionalist, we can offer multiple things to these patients to improve their outcomes. I'm a huge fan of ultrasound, so I use ultrasound
to guide my needles as often as possible. I'm using a glove because I'm gonna end up doing cryoablation in the near field of that metastasis that I showed you. On the image on the right hand side, you can see the cryoprobe going down
into the shadowing cryoablation defect. It's treating that lesion, but just above that, you can see a horizontal white line, which is actually a needle that I'm injecting saline to keep the skin safe as we're doing the cryoablation. By using the glove with the saline in it,
I can actually use that as a standoff pad to sort of see that skin and make sure that the cryo energy and that ablation zone is not coming up into the skin. Just a nice technique with ultrasound, very simple. And then, at the same time, while I'm doing the cryoablation just lateral to that,
I'm taking an ultrasound guided approach and dropping a needle down in front of the aorta and doing that celiac plexus block and neurolysis at the same time. So the patient gets the ablation for pain control and they get the neurolysis for pain control
and had significant improvement in their pain. You can see there the cryo defect. We delivered the alcohol to perform the neurolysis and the patient had significant improvement for a while. Ultimately, her pain recurred, but she then ended up going to hospice and passing.
We definitely offered her improved pain control and quality of life for at least a short period.
These have been looked at and there's meta analysis of over a thousand patients that shows that this is a highly effective way to control pain if offered early. The later you offer this, these blocks,
the less effective they are. But 70 to 90% of patients experienced either partial or complete pain relief at some time prior to their death.
Lumbar sympathetic block and neurolysis is another block that's not often used and actually can solve a lot of difficult problems.
In the lower extremities, if you have non-reconstructible vascular disease, patient can't have a bypass or a stent. If you have vasospasm, again if you have frostbite, if you have some of these more rare entities like Buerger's disease or these arteritis syndromes,
you can use this block to improve pain control. Phantom limb pain if you've had an amputation, peripheral neuropathies. But also this can be good for patients that have pain related to their kidneys, ureters, or genitalia. If you have somebody who has a terrible kidney stone
and they're not being controlled well with their narcotics, you can actually do this block and temporarily improve their pain. The lumbar sympathetic chain is just there, lateral and anterior to the vertebral body, just behind the aorta and the IBC.
It runs on both sides of the vertebral body all the way down into the pelvis. A block at three levels followed by injection of alcohol effects this neurolysis. We basically disrupt the sympathetic chain and you get reflex vasodilatation
in the lower extremity that you've treated. In this particular patient who has rest pain and can't have a bypass, we do this block and lo and behold, you get this reflex vasodilatation. It's a little bit subtle based on my poor photography, but there was definite hyperemia,
definite improved blood flow. This has been shown to reduce the incidence of amputations. It gets people out of rest pain and can be a nice bridge if you're waiting for your stent or other procedure. Just a nice simple way to help a patient and improve their quality of life and pain control.
That's basically what I just said, so let's skip that slide.
The superior hypograstric block is becoming kind of more commonly seen. In those practices that are doing it, a lot of uterine artery embolization, this is a really nice way to improve patients'
crampy abdominal pain or crampy pelvic pain that's related to uterine ischemia after uterine artery embolization. There have been authors that have proposed that to do UAE as an outpatient procedure, that we should couple the UAE procedure with this block.
It's good for pelvic pain, both uterine contractile pain, but also for cervical, vaginal pain, rectal, as well as bladder related pain. For those cancer patients, this is also a good block to consider. These are all palliative interventions
that are very simple to perform and can really improve patients' quality of life. Again, getting back to this really busy slide, if you target this lower hypogastric region, you're basically picking up the splanchnic nerves that innervate the large intestine,
the small intestine, the ovaries, the scrotum, the urinary bladder, and the perineum. On the right hand side, you can see the fluoroscopic guided way to do this, which is basically just to target the disc space between L5 and S1.
The other way that people do it is that during their uterine artery embolization, they'll take a catheter and put it up and over the bifurcation so that you basically then outline where the bifurcation is and then you just stick your needle right there in the V of your aortic bifurcation.
You take the needle just underneath the aortic bifurcation and dock it up against the vertebral body, pull your needle back, do your block, and you have a significant improvement in the patient's pain.
Some other less often understood or offered blocks are the ganglion of impar block
which is just anterior to the sacrum, kind of at the junction of the sacrum and coccyx. The ganglion of impar, again, sympathetic chain innervates the rectum, the perineum, and is very useful in patients who have coccydynia, patients that have a coccyx fracture
or have coccydynia, which is actually much more common than you might expect, than you might think. Very simple to do, you can either do it under fluoroscopy laterally, but I think that with our imaging capabilities, we can do this in a very elegant manner,
so you can go just across the sacrum or through the sacro-coccygeal ligament. You can see that I've brought an 18 gauge needle down through the bone and through that needle, I pass a 22 gauge needle. Obviously you have to watch out
for the important structures anterior, so I had to come right up to the rectum, but I couldn't pass the needle through the rectum, that would be a bad day. I inject a little bit of contrast, inject some bupivacaine and lidocaine,
and the patient gets relief of their pain.
Just finishing up, neurolysis and nerve ablation. We talked a little bit about this, but the goal is to permanently disrupt the axons and the myelin sheath. You can do it chemically with alcohol or phenol. But more and more people now are offering
radiofrequency ablation or cryoablation as a more precise way of performing these ablations. Radiofrequency ablation probably has the most data after alcohol and phenol. It's inexpensive and it has a long track record. Cryoablation is now being reported in the literature.
It's easy to see on CT as my colleagues have demonstrated. It's good in soft tissue tumors, but we still have very early data. Some people are actually looking at MR-guided focus ultrasound, very sexy, very expensive technology, very niche.
I don't really see that becoming a major player. I think it's really gonna be RFA and cryoablation,
as well as the chemical. In thermal RFA, the target is to get the nerve to 70 to 90 degrees, which basically then disrupts the axonal continuity.
You get this Wallerian degeneration of the nerve because you disrupt the myelin, and the axon, and the endoneurium. Basically you're doing what the surgeon does by basically stopping that conduction of the nerve. Pulsed RFA is a newer way of addressing this
and this is not entirely well understood. Basically you're doing a non-lethal ablation affecting what's called modulations. You're modulating the nerve by passing an electric current across the nerve. And what that's supposed to do is reset the nerve.
There's actually genetic changes that occur in the dorsal root ganglion based on doing this modulation. I will tell you that if I ask my colleagues on this esteemed panel, how does pulsed RFA work, they would all give me kind of funny looks, I suspect. Because it really isn't totally understood right now.
Cryoablation is similar to thermal RFA where you basically are damaging the nerve
and stopping conduction. Just to finish up, a couple of nice cases. This one that we did recently, a guy had pleural plaques and had significant neuropathic lancinating pain
in his rib cage and you can see on the right hand side, we've brought the needle down underneath the ribs, so this is sort of a sagittal view on ultrasound of the rib. You go and target underneath the rib where the intercostal nerve runs. You do your diagnostic block.
We did that and the patient had significant improvement in pain, and then we come in behind that and do thermal ablation, so we're taking the RF probes and we're placing them in multiple intercostal nerves around where the patient's pain is
and you can see that we've marked on his skin the exact areas where he has profound pain. You can't even touch his skin without him having severe pain. And after we finished the thermal ablation, he still had pain, but he could rub his skin,
he could wear a shirt, he could do more things. That was definitely successful.
We're doing this in the knee where we do the geniculate nerves. We target the medial and lateral superior geniculate nerves, as well as the inferior medial geniculate nerve.
This is the approach, you can see the probe placed right where the geniculate nerve lives in the lateral position. This is what it looks like when we're placing the probes. We place these sheath needles. We inject some bupivacaine and lidocaine,
and then we form the RFA. This is another patient where we performed the medial and lateral superior geniculate and then the inferior medial geniculate ablation with significant relief of this patient's pain.
In conclusion, nerve blocks are important
because you can diagnose and sort of hone in on where is the pain coming, so it has a diagnostic role. You can get people out of an acute pain crisis so you can present a huge value to your patients. This has become a big part of our practice. The palliative care docs love us
because we're very responsive as a practice and we can get these people out of pain. Once you've diagnosed that and proven that the block works, you can then do a more permanent ablation or neurolysis as we've demonstrated. I would say that these are easy, low risk procedures
that again, I would take this back to your practice and bug your IRs and say, "How come we're not doing these?" if you guys aren't doing these because patients love this stuff. They really appreciate these very simple procedures. Thank you for your attention.
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