Episode #130 Keeping Patients Safe During Epidural Steroid Injections

December 27, 2022

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Welcome to the next installment of the Anesthesia Patient Safety podcast hosted by Alli Bechtel.  This podcast will be an exciting journey towards improved anesthesia patient safety.

This is an article from our archives episode. Our featured article today is from the Spring 2011 APSF Newsletter. We know that things have changed since then, but this article is of interest from our archives and we are going to review it now. Our featured article today is “Avoiding Catastrophic Complications from Epidural Steroid Injections” by Stephen Abram and Quinn Hogan.

Here is the citation that we talked about on the show today.

Manchikanti L, Sanapati MR, Soin A, Manchikanti MV, Pampati V, Singh V, et al. An updated analysis of utilization of epidural procedures in managing chronic pain in the Medicare population from 2000 to 2018. Pain Physician. 2020;23(2):111–26.

Spinal cord injury following epidural steroid injection may occur due to epidural bleeding, epidural abscess, direct spinal cord trauma, and embolization of particulate matter into the arterial supply of the cord. The risk for epidural bleeding and epidural abscess may be minimized by using strict aseptic technique and following the guidelines related to the use of antithrombotic and thrombolytic agents. For more information about these guidelines check out the practice advisory at ASRA.com which was updated in 2019, “Updates to the ASRA Guidelines for Interventional Pain Procedures.

We hope that you will consider applying for the joint APSF-FAER Mentored Research Training Grant. The Letter of Intent submissions for the 2023 grant open December 1st, 2022, and close on January 1, 2023. This is a two-year, $300,000 award to help anesthesiologists develop skills and preliminary data in order to become independent investigators in the field of anesthesia patient safety. The first step is the letter of intent prior to submitting a full application. So, what are you waiting for? Get your letter of intent in!

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© 2022, The Anesthesia Patient Safety Foundation

Hello and welcome back to the Anesthesia Patient Safety Podcast.  My name is Alli Bechtel, and I am your host. Thank you for joining us for another show. It is almost the new year, but before we look forward to the future of anesthesia patient safety in 2023, we are going to head back into our archives to one of the most popular APSF articles of all time.

Before we dive into the episode today, we’d like to recognize Masimo, a major corporate supporter of APSF. Masimo has generously provided unrestricted support to further our vision that “no one shall be harmed by anesthesia care”. Thank you, Masimo – we wouldn’t be able to do all that we do without you!”

This is an article from our archives episode. Our featured article today is from the Spring 2011 APSF Newsletter. We know that things have changed since then, but this article is of interest from our archives and we are going to review it now. Our featured article today is “Avoiding Catastrophic Complications from Epidural Steroid Injections” by Stephen Abram and Quinn Hogan. To follow along with us, head over to APSF.org and click on the Newsletter heading. Fifth one down is APSF Newsletter archives. Then, scroll down until you get to Spring 2011. Then, scroll down until you get to our featured article today. I will include a link in the show notes as well. Let’s jump in our time machine and get ready to learn more about keeping patients safe during epidural steroid injections. Here we go.

[Airplane Takeoff Music]

The authors start off with a review of the procedure, epidural steroid injections which are indicated for patients with lumbar and cervical radiculopathy. In 2001, this procedure occurred at a procedure rate of about 26.5 per 1000 in the United States in Medicare recipients 65 and older. A 2020 study by Manchikanti and colleagues published in Pain Physician revealed that rates of epidural injections in Medicare recipients declined by 20.7% between 2009 and 2018 with an annual decline of 2.5%. I will include the citation in the show notes for further review as well.

For epidural steroid injections, there is no mandatory reporting for complications so we do not know the rate of serious complications in the United States. In addition, anesthesia professionals performing this procedure may be reluctant due to litigation concerns. If we look at the ASA Closed Claims Project, 40% of all the pain management case claims between 1970 and 1999 occurred following epidural steroid injections. The claims included the following: 14 cases of spinal cord injury with 6 patients who developed paraplegia and 1 patient with quadriplegia. Over that same time period, there was a dramatic increase in the use of this procedure and there were concerns that the incidence of devastating complications increased as well. It is critical to understand the serious risks associated with this procedure as well as the patients who will benefit from receiving epidural steroid injections. Epidural steroid injections should be avoided for patients with the following: purely axial back pain, neural claudication, and non-radicular sources of back and leg pain who are unlikely to have improved pain control following the procedure.

Back in 2011, what did we know about complications following epidural steroid injections? We have learned about spinal cord injury complications from physicians who work as expert witnesses in malpractice claims informally and a few published reports of complications. Let’s review these complications now.

Spinal cord injury following epidural steroid injection may occur due to epidural bleeding, epidural abscess, direct spinal cord trauma, and embolization of particulate matter into the arterial supply of the cord. The risk for epidural bleeding and epidural abscess may be minimized by using strict aseptic technique and following the guidelines related to the use of antithrombotic and thrombolytic agents. For more information about these guidelines check out the practice advisory at ASRA.com which was updated in 2019, “Updates to the ASRA Guidelines for Interventional Pain Procedures.”

Next up, let’s discuss the risk of direct spinal cord trauma. There are only a few published reports of this complication and information based on medical records observed by expert witness physicians in malpractice cases. Spinal cord injury may occur following needle penetration with a wide range of injury severity. The most devastating complications occur following injection of any material into the spinal cord and avoidance of this is paramount. In order to keep patients safe, you must confirm proper needle placement before injection of any material, including contrast dye. Cervical epidural injections are associated with the majority of the most serious injuries. The authors provide some insight into how to minimize the risk of serious injury and to keep patients safe during epidural steroid injections.

First, obtain and review MRI scans before performing the procedure. This can provide vital information about disk herniation with may shift the spinal cord posteriorly and eliminate the posterior subarachnoid space. Patients who have had cervical spine surgery in the past may have scar formation with adherence of the dura to the more superficial tissues at the proposed injection level which increases the risk for direct needle trauma to the spinal cord. Patients with pre-existing canal stenosis and spinal cord compression are at risk from the additional pressure created by the volume of drug injected or the pharmacological effect of those drugs leading to neurological injury especially if there was a pre-existing loss of function.

The next step is to avoid epidural needle placement above C6-7 due to the anatomical considerations. There is usually a small amount of epidural fat in the midline posteriorly at C7-T1 which creates a space between the ligamentum flavum and the dura. There is minimal midline epidural fat at C6-7 and non at C5-6 and above. Keep in mind that low volume cervical injections may spread upwards by several segments. If steroid placement at a higher level is indicated, you may consider use of an epidural catheter in the upper thoracic spine which may then be advanced under fluoroscopy to the desired level.

Another consideration is to obtain a lateral view of the spine after the needle is placed and prior to the injection. This image may be difficult to obtain at the lower cervical level due to the superimposed shoulder joints, especially in patients with thick necks. One option is to obtain a “swimmer’s view” with one arm at the side and the other arm raised above the head to successfully obtain a view of the needle within the spinal canal.

Next, it is important to avoid deep sedation during this procedure since a patient may become agitated and move unexpectedly during deep sedation leading to increased risk for injury. In addition, paresthesias may alert the proceduralist of needle contact with the spinal cord. There is a concern that moderate or deep sedation or general anesthesia may block any paresthesias or motor responses during needle contact with the spinal cord. Non-sedated patients may not always feel a paresthesia during needle contact with the cord, but it appears that an awake patient adds a level of safety to this procedure.

A final consideration is to avoid the use of the hanging drop technique to identify the epidural needle placement since it is not reliable to identify the epidural space. There are reports of spinal cord injury following failure of the hanging drop technique to indicate epidural needle entry.

The next big complication covered in the article is ischemic spinal cord and brain injury. Once again, we are talking about a devastating complication. There are reports of spinal cord, brainstem, and cerebellar infarction following cervical transforaminal epidural steroid injections starting in the early 2000s. It was thought that these complications occurred from accidental injection of particular material into radicular arteries next to the targeted nerve root. A 2003 article by Baker and colleagues revealed that contrast dye could spread into a radicular artery during transforaminal injection even with careful and appropriate technique, thus ischemic injury could occur following intra-arterial drug injection and all commercially-available steroid suspensions available for this procedure contained particles that were large enough to occlude arterioles and capillaries. Spinal cord injury has also occurred after transforaminal steroid injections at lumbar, sacral, and thoracolumbar levels. When an intra-arterial injection occurs, the contrast dye may spread into the epidural space as well as intravascularly so that it is possible to miss the intra-arterial spread. Use of digital subtraction fluoroscopy may help to improve visualization of intravascular dye. In addition, using small gauge needles may increase the likelihood of intra-arterial spread. Unfortunately, using a pencil point side port needle does not prevent intra-arterial injection. Another consideration for spinal cord injury following foraminal injection is from needle placement in the dorsal root ganglion which is a large structure at the outer margin of the intervertebral foramen. The dorsal roots at this level are short, only about 1cm long which increases the chance for an injection into the spinal cord. Now, let’s review several considerations to help decrease the risk for intraneural injection or intra-arterial embolization of particular steroids.

First up, after careful aspiration, it is important to use live fluoroscopy while injecting contrast. Then, obtain a still image a few second later to make sure that the dye pattern has not changed. Using digital subtraction may further enhance the safety of this procedure. The use of small extension tubing to inject dye can help to minimize needle tip movement during dye injection and steroid injection.

Next, consider administering a local anesthetic test dose with minimal sedation. Then, be on the look out for signs of systemic symptoms as well as numbness and paresthesias locally.

Another consideration to increase the safety of this procedure is to use non-particulate steroids. This may be controversial since soluble steroid may not have equivalent efficacy and these soluble steroid preparations do not stay in the spinal canal for very long.

Finally, you may want to use the interlaminar approach, especially for cervical injections. Since the arteries supplying the spinal cord to not transverse the dorsal epidural space, there is a much lower risk for injection into a radicular artery or dorsal root ganglion with this approach. In theory, the transforaminal approach to the epidural space may be superior, but this is based on a non-controlled case series. In addition, it is important to avoid performing transforaminal injections for patients when contrast dye is contraindicated. When consenting patients for the procedure, it is important to discuss the risks associated with both types of injections.

We have reached the conclusion to our article from our archives from 2011. We just reviewed the complications, but the benefit of epidural steroid injections is to facilitate recovery from radiculopathy following disc herniation and for pain relief for patients with chronic radicular pain. Keep in mind that this procedure will provide little relief for patients with axial back pain or neural claudication from spinal stenosis and thus should be avoided for these patients. In addition, epidural steroid injections may not decrease the need for spine surgery or improve long-term outcomes. The authors leave us with this call to action that I am going to read now: “It is important that patients understand the risks and benefits of these procedures and that we do everything possible to prevent rare but catastrophic neurological complications.”

Just in time for the new year, we made it back from our quick trip into our archives. If you have any questions or comments from today’s show, please email us at [email protected]. Please keep in mind that the information in this show is provided for informational purposes only and does not constitute medical or legal advice. We hope that you will visit APSF.org for detailed information and check out the show notes for links to all the topics we discussed today.

If there is an article from our archives that you would like to hear more about on this podcast, please let us know with an email or tag us on twitter @APSForg using the hashtag #APSFpodcast. We are looking forward to another great year of APSF newsletters, articles between issues, podcasts, and so much more in 2023 and we hope you will continue to tune in. If you get a change, we hope that you will share this podcast and the APSF newsletter with any of your friends or colleagues who are interested in anesthesia patient safety.

Until next time, stay vigilant so that no one shall be harmed by anesthesia care.

© 2022, The Anesthesia Patient Safety Foundation