In our next section, we will discuss commonly performed interventional pain procedures. When looking at the spine, there's a systematic approach trying to figure out where the pain generator is coming from. There's the posterior compartment, which structures are innervated by the dorsal ramus of the spinal nerve, which includes the facet joint. There's the anterior compartment, which includes the vertebral bodies and intervertebral disc. And then there's also the neuroaxial compartment, which can produce pain you see in here. This type of pain usually can cause radicular more than axial back pain. Some of the causes of neuroaxial compartment pain are disc herniation into the central canal or foraminal zone. You can have ligamentum flavum thickening, facet hypertrophy, spondylosis, epidural lipomatosis. This can lead to radiculitis or radiculopathy. Also can lead to spinal stenosis. Looking at basic definitions for disc herniations, there's a protrusion and extrusion. A protrusion is where the depth in any plane is less than the base of the herniation in the same plane. An extrusion is where the depth in any plane is greater than the base of herniation in the same plane. Here you can see the protrusion on the left with the extrusion on the right. When looking at disc herniations, you usually have four stages of the herniation. A degenerative disc can lead to a disc protrusion. That in turn can be a prolapsed disc, which can turn into a disc extrusion. And if it gets bad enough, some discs can have something called a sequestered disc, which is where fragments of the herniated nucleus pulposus is separated from the main part of the disc. There can be a combination of chemical and mechanical factors that can cause irritation to nerve roots, which can lead to radicular pain. There is mechanical irritation, which is the disc herniation or pyramidal stenosis itself can compress the nerve root or the dorsal root ganglia, causing abnormal neuronal discharges along the nerve root. There's also chemical irritation, which is from the disc degenerative released inflammatory mediators resulting in abnormal discharges from the dorsal root ganglia. About 95% of all disc herniations occur in the lumbar spine at L4-5 and L5-S1, and the most common cervical level is C6-7. When looking at radiculopathy symptoms, the patient will often describe them as sharp, stabbing, or shooting pain going down one of their limbs. The pain is worse with coughing, sneezing, or straining. They may have a straight leg raise in the seated or lying down position and or neurological deficits. They can have a loss of reflex, weakness, and gait impairment. Some of the common mechanisms of people getting radicular pain is lifting heavy objects while bending and twisting or repetitive spinal motions that can. When evaluating a patient with radicular symptoms, the history and physical are very important. The dermatomes are regions of altered sensation from an irritated or damaged nerve root. These symptoms that follow a dermatome, usually numbness, tingling, or pain, may indicate a pathology that involves the related nerve root. These symptoms can follow the entire dermatome or just part of it. Dynatomes, though, are a distribution of referred pain, which are unlike dermatomes, which only deal with sensation from the cervical root irritation. In these patients, you might consider an EMG or a nerve conduction study to help differentiate. You can have spinal stenosis in the central canal, causing central spinal canal stenosis, or it can be in the foraminal area, causing foraminal stenosis. Some of the causes of stenosis can be you were just born with it, a congenitally small canal, you could have degenerative osteophytes coming off some of the facet joints or other bony areas, you could have a slip with a spondylolisthesis, you could have facet joint hypertrophy, ligamentum flavum hypertrophy, and or also a disc herniation. One of the hallmark symptoms of spinal stenosis is called neurogenic claudication. This is when a patient is walking upright or standing, and they'll have pain or fatigue or pair of seizures going down into their lower extremities. This is worse with prolonged standing or walking, and it is relieved by resting or leaning forward on objects. You can ask a patient when they go shopping, do they have to lean on their shopping cart? And a lot of times, they'll remember for sure that the only way that they can complete their shopping is by leaning forward on their shopping cart. Getting into some of the interventional pain procedures that we commonly do, the most commonly performed one is probably the epidural steroid injection. You can do this in two different ways. One is an intralaminar, and the other is a transforaminal approach. This type of injection is better for radicular pain but can also help axial back pain sometimes. A lot of the data is controversial about does this work, what are the risks, but we try to offer this to our patients that do not want to have surgery as another option to try to help alleviate some of their back and or radicular pain. One of the approaches of an epidural injection is the intralaminar approach. This we direct a needle at the midline or paramedian intralaminar space. We go through the different structures to get to that area, which is the skin, subcutaneous fat, supraspinous ligament, intraspinous ligament, ligamentum flavum, and then finally get to the epidural space. We use a loss of resistance technique, which is usually with a glass or a plastic syringe. And whenever you get through the ligamentum flavum, you'll have a loss of resistance when the needle enters the epidural space. We inject a steroid into the epidural space, which is an anti-inflammatory. We do this procedure for usually acute radicular pain due to a disc herniation. Some of the common complications seen with an intralaminar epidural steroid injection is an intradural injection, a dural puncture, and that can lead to a low-pressure headache. Here's a few pictures of an intralaminar epidural steroid injection. On the left is an AP view, where we rotated the camera or obliqued it to the left so we could try to aim for the left paramedian intralaminar space. Usually we would target the left or right side if the patient is having worsening symptoms on the left or right side. On the right is a lateral view of the contrast going into the epidural space. The other type of epidural that we can perform is called a transforaminal epidural steroid injection. This is where we direct a needle at the foramen, trying to localize a specific nerve root. We would try to use this procedure if someone has clear indications of a single or maybe two-level nerve root where they can describe the symptoms, and we have a good indicator from an MRI saying that those are where the symptoms are coming from. We inject a steroid into the epidural space, just like the intralaminar approach, which is an anti-inflammatory. The indications for this are acute radicular pain due to a disc herniation as well, and some of the complications are also similar. You can have transient increased pain, spinal cord infarction, or nerve trauma. Here are a couple pictures of a transforaminal epidural steroid injection. On the left, you can see the contrast flowing along the particular nerve root. It's very linear going along that nerve root. On the right is most likely where they use the medication following the contrast, and you can see the contrast spread going left down the nerve root, and if you can look on the right side, it does go up into the epidural space a couple levels. In the posterior aspect of the spine, some patients can have facet joint pain. The facet joint is just like any other joint in your body and can have arthritis and or pain associated with it. Fifteen to forty percent of non-radicular low back pain comes from facet joint pain. Forty to sixty percent of non-radicular neck pain can come from facet joint pain and can be multifactorial with other pain generators and is also difficult to diagnose with just the history of physical and imaging. Looking specifically at the lumbar facets, sixteen percent of axial load assumed by the facets with prolonged standing in a lordotic posture. This can increase up to seventy percent of an axial load with lumbar spondylosis and degenerative disc disease. People with facet pain can be subject to microtrauma to the facet, capsular tears, synovial inflammation, degenerative arthritis, segmental instability, and also post-surgical adjacent level stress. Lumbar facet pain can cause low back pain with possible radiation into the buttocks, groin, and proximal leg. On the right, the picture there shows the primary pain area of lumbar facet pain with the secondary and tertiary pain areas going all the way down into the posterior caps. The pain can be described as dull, achy, deep. Sometimes it's difficult for the patient to describe. It's worse with twisting, bending, and standing. Since this is just a joint facet pain, they will have no neurological deficits. And the degenerative changes, they can also be seen on radiological studies seen as on x-ray, CT scans, and MRIs. The facet joints in the neck can also have referral pain patterns. We use the patient's subjective to help determine which procedural level we would like to perform to see if we can help alleviate some of that pain. We always give patients a pain diagram and ask them to try to be as specific as possible where they're having their neck pain. Sometimes they can fill out the pain diagram and show that it is in the neck region, and it kind of goes down into the trap. So we can use that diagram to say, hey, it might be C4-5, C5-6, or C6-7, as opposed if they were having upper neck and the base of their skull pain, it might be more of a C2-3, C3-4 region. There are a few different types of procedures that we can do for facet joint pain. One is a direct facet joint injection where we inject into the joint. This is for therapeutic purposes, so we will use steroid and sometimes a numbing medication. With this, we commonly do it under fluoroscopic guidance, but there are physicians that are able to do it under ultrasound guidance. The picture on the right, you can see the needle inside the facet joint with contrast going in and filling the top and the bottom of the joint. This procedure is being commonly less performed because insurances are not paying for it. Instead, they will pay usually for the next procedure, which is a medial branch block. Looking at the medial branch nerve itself, it is a medial branch off the dorsal ramus nerve. It innervates the facet joint as well as the multifidus muscle. Each facet joint is innervated by two different medial branch nerves, the one from on top and the one from below. For example, the L4-5 facet is innervated by the L3 and L4 medial branch. The cervical spine is different, though. The C3-4 facet is innervated by the C3 and the C4 medial branch. On the right, you can see the L4-5 facet in red, and you have the L3 and L4 originating branches in green going to innervate that joint. Another procedure that we perform commonly for facet joint pain is called a medial branch block. This is diagnostic in purpose due to us injecting anesthetic medication around the nerve. When we target the medial branch nerves, those are the nerves that are transmitting pain signals from the arthritic joints to our brain. By using the anesthetic, it will help relieve the pain for four to eight hours, and it will help relieve the pain for four to eight hours. After the procedure is performed, we will give a patient a pain diary. It is very important for them to know that the pain will most likely come back after the anesthetic medication has worn off. So even if they get pain relief for one day, it is not a failed procedure. Another procedure we can do for facet joint pain is called a medial branch RFA, or a radiofrequency ablation. This is a percutaneous thermal lesioning of the medial branch that is innervating the painful joint. We try to park the needle parallel to the nerve to get the most bang for our buck, I guess you would say, with burning the nerve. If you can only burn a small amount of the nerve, it will grow back faster and not give the patient as much pain relief for a longer time. If you can park it parallel to the nerve, you would hopefully burn more of the nerve and give the patient a longer-lasting pain relief. For this procedure, we use a sensory and motor stimulation during the procedure to help us identify the location of the nerve to see if we're close with the needle, as well as make sure that there's no motor stimulation going down into the leg. Another joint that can cause some patients some pain is the sacroiliac joint. It is a joint that connects the sacrum and the ilium. It runs from posterior medial to anterior lateral. Every person's joint, though, is slightly different, so when we're trying to adjust the C-arm, we have to rotate it and oblique it different ways towards the side of the pain and also away from the side of the pain to see which one opens up the sacroiliac joint. The nerve supply to that joint is variable, and from the pain that can come from the SI joint, it can come from multiple sources. When a patient has sacroiliac joint pain, sometimes they'll describe it as low back pain worse with transitional movements going from sit to stand or standing to sitting. The patient is laying prone on the table. Here on the right side, you can see the needle going down to the bottom one-third of the joint, which is where the opening for the joint that we try to target is located. You can see that contrast line spreading up and down the joint line there. This joint injection can sometimes be difficult due to severe osteophytes in everyone's joint, again, being different. A common source of anterior compartment pain can come from a compression fracture of a refubal body. This is usually due to osteoporosis, but other causes can be traumatic causes or pathological fractures or from multiple myeloma. Usually, the patient will describe themselves as having axial back pain, which is worse when walking and standing and better while lying down. They can have tenderness over the compression fracture level itself and also have pain with percussion over the compression fraction level. A procedure that we can try for these compression fractures is called a vertebroplasty and a kyphoplasty. These are used to treat acute painful compression fractures. They work by injecting cement into the fractured vertebrae, which helps fuse the bone fragments and strengthen the vertebral body and provide some pain relief. A kyphoplasty is different than a vertebroplasty because it uses a balloon to create a space for the cement to go to. Some of the complications that someone will see is an adjacent segment fracture, which is a fracture of the level that is adjacent to the one that we are putting cement into later on. And also, during the procedure, we can have cement embolization, where there's cement that leaks out of the intended vertebral compression fracture area and can go into either the surrounding discs, anterior to the vertebral body, and worst-case scenario, into the posterior aspect of the vertebral body or into the blood system. Another procedure we can perform is called a lumbar discography. It is a diagnostic procedure used to evaluate for potential discogenic pain generators. For the interpretation of the discography, we look at, is it evoked pain? Is it the pain that they normally feel, or is it something else? We also have to inject and inflate a normal disc. That should have different pain than what they feel in the bad disc, which is likely to evoke pain at pressures that are below 15. We look at the volume that can be injected into the disc. A normal disc accepts less than 1 milliliter before resistance, with a cervical and thoracic being 0.25 and 0.5 milliliters. And we also look at the morphological disc evaluation using the modified dialysis method. And we also look at the modified dialysis classification, which is seen on the right. A grade 0 describes a normal lumbar disc in which contrast is limited to the nucleus propulsus. A grade 1 through 3 designates discs in which contrast extends to the inner, middle, and outer third of the annulus fibrosus. A grade 4 describes a diffusely degenerated disc in which several annular tears extend to the periphery of the annulus. A grade 5 describes a large tear that results in contrast extending circumferentially to more than 30% of the disc's circumference. Some people say that this is a controversial procedure and we're doing less and less of them, just because when you do have to place a needle into a healthy disc, there is concern for further disc injury and disc degeneration. Another procedure we can perform is called a spinal cord stimulator. This procedure is used for patients with felled back syndrome and radicular pain syndromes. Some have approved for panful diabetic neuropathy. In this procedure, we use a 14-gauge tubing needle to access the lumbar epidural access space and subsequently thread a spinal cord stimulator lead over to a targeted region of the dorsal column. For these procedures, we do a trial before implant, which is helpful for the patient did it not help your pain? Did it help the pain that was going down into your legs or low back pain? On the right, you can see an image after the leads were placed into the, that looks like the top of T7, where they usually span two to three vertebral bodies. Another procedure that we can perform is called a sympathetic block. Usually, this will target either the stalate ganglion block, a ciliate plexus block, a lumbar sympathetic nerve block, a hypogastric plexus nerve block, or a ganglia of MPAR injection. These target the sympathetic nervous system. Mostly, we do the stalate ganglion blocks and the lumbar sympathetic blocks for CRPS, but other reasons people can perform these sympathetic blocks could be for cancer pain, vascular insufficiency, phantom limb pain, hypohidrosis, and then there's others. This targets the sympathetic ganglion on the lateral and anterior aspect of the vertebral body. On the picture on the right there, you can see the needle going into that lateral anterior aspect of the vertebral body, where you would play some contrast to see if it flows along the anterior border, and then you would place your medication. And lastly, I'll touch on intrathecal pain pumps. These are medical devices that deliver medication into the intrathecal space, which are designed to give smaller doses to give less side effects compared to high-dose oral medications. For this, I would review the recommendations given by the Poly-Analgesic Consensus Conference on best practices and guidelines. Usually, patients will undergo a trial before implantation, just like the spinal cord stimulators, where a physician would inject either pain medications or a different type of medication into the intrathecal space to see what kind of response they have prior to placing a permanent pain pump.

interventional pain procedures

spine-related procedures

disc herniation

epidural steroid injections

facet joint injections

radicular pain