Chronic low back pain(LBP) and neck pain is the most common cause for years lived with disability in the world.[1][2][2][2] There are a variety of causes that can lead to LBP that include disc herniation, facet arthritis, discogenic pain, etc. Epidural steroid injections have been utilized for pain relief for such conditions since 1952. When indicated, epidural steroid injections are an invaluable non-surgical treatment for low-back pain radiating to the lower extremities and less commonly, neck pain radiating to the arms. The procedure involves the administration of steroids into the epidural space to treat the discogenic origin of the pain. If successful, epidural steroid injections will provide pain relief, allowing restoration of function and/or return to a physical therapy regimen.[3][4][5][6]
The spinal cord and brain are covered by three protective layers known as meninges. The innermost layer is the pia mater, which articulates directly with the surface of the spinal cord. The middle layer is known as the arachnoid mater. Lastly, the dura mater is the outermost and thus toughest protective layer of the spinal cord. It is separated from the vertebrae by the epidural space. The epidural space contains the dural sac, blood vessels, fat, connective tissue, and spinal nerves. The contents of the dural sac include the spinal cord (ending at L1/L2) and the cauda equina. The spinal dura mater is critical to the peripheral nervous system as it creates pathways (via dural sheaths) by surrounding exiting nerve roots from the spinal cord.
The vertebral column also acts to protect the spinal cord. It consists of 33 bones (vertebrae), many of which are separated by an intervertebral disc. This includes seven cervical, twelve thoracic, five lumbar, five sacral (fused), and four coccygeal (fused) vertebrae. Spinal nerve roots exit the spinal column via two lateral openings, called intervertebral foramina, formed between two contiguous vertebrae.[7]
Epidural steroid injections treat pain caused by irritation and inflammation of spinal nerve roots. One specific type of pain, known as radicular pain, causes radiation along the dermatome of the affected spinal nerve. Many conditions may irritate the spinal nerve roots, which most commonly presents with low back (lumbar) pain with radiation down the buttocks or legs (e.g., sciatica). Also prevalent are patients with a neck (cervical) pain with radiation to the arms.[8][9][10]
The most common cause of spinal nerve root irritation is intervertebral disc pathology. In herniated discs, the center portion of the disc (nucleus pulposus) pushes through the outer layer (annulus fibrosis) placing pressure and ‘pinching’ the adjacent spinal nerve root. This pressure results in pain, weakness, and/or numbness in the distribution of the irritated nerve. Similarly, in degenerative disc disease, the breakdown of intervertebral discs over time may cause the collapse of intervertebral space resulting in compression of spinal nerve roots.
Another common indication for epidural steroid injection is nerve root irritation secondary to spinal stenosis. Spinal stenosis is a condition causing narrowing (stenosis) of the spinal canal or the canals of exiting nerve roots. Spinal stenosis is most commonly caused by arthritis of the vertebral joints (facets) or intervertebral disc pathology as discussed above.
Other conditions in which epidural steroid injections may be indicated are:
One of the systematic reviews published evaluated 70 studies for lumbar epidural steroid injections, evidence for efficacy was good for lumbar disc herniations, fair for spinal stenosis, and poor for failed back surgery syndrome.[11] Another meta-analysis published showed good efficacy for use of epidural steroid injections for spinal stenosis and lumbar radiculopathy.[12] Kennedy et al. published the results of a prospective study showing the effectiveness of ESI in the treatment of lumbar radicular pain. Even though patients had good pain relief, but it was found that the pain relief was short-lived.[13] Another study conducted by Singh et al. showed that two-level transforaminal epidural steroid injections provide better pain relief compared to one-level TFESI.[14]
While the evidence of efficacy for Epidural steroid injections is strong, the longevity of pain relief is still not great and patients do need other forms of therapy for sustained pain relief.[15][16][1]
Absolute contraindications to epidural steroid injection include:
Relative contraindications to epidural steroid injections:
Epidural steroid injections require:
Epidural steroid injection may be completed with only topical local anesthesia or under intravenous (IV) sedation. In either case, it is necessary to have blood pressure cuffs, cardiac monitors, and pulse oximeters to monitor vital signs.
Staff includes a physician trained in epidural steroid injections, nurse or assistant, a fluoroscopic C-arm operator, and an anesthesiologist to monitor patient vitals. All staff should be trained for the management of potential complications of the procedure.
Risks and benefits of the procedure should be discussed with the patient and if in agreement, the patient must sign a written consent. Before the injection, a time-out is necessary to verify patient identity and injection site. The patient is to lie in a prone position on the fluoroscopy table, and once the location of injection is identified, the area should be marked, cleaned with betadine, and covered with sterile draping.
Epidural steroid injections may be classified by location (cervical, thoracic, or lumbar) and by the path of the needle (interlaminar, transforaminal, or caudal). In this discussion, we will review the different techniques for interlaminar (between the lamina), transforaminal (across the foramen), and caudal (via the sacrum) epidural steroid injections.[17][18][19]
Interlaminar Epidural Steroid Injection (medial approach)
With the patient lying prepped and in a prone position, the interlaminar space between two contiguous vertebrae is identified via an anteroposterior (AP) view on fluoroscopic x-ray. Next, the skin and underlying tissue are injected with local anesthetic (e.g., lidocaine or bupivacaine). Using a midline or paramedian approach between the spinous processes, an epidural spinal needle is inserted into the intended injection site. From superficial to deep, the needle penetrates the skin, subcutaneous tissue, supraspinous ligament (median approach) or paraspinal muscles (paramedian approach), and the ligamentum flavum. A lateral view with the fluoroscopic x-ray is then obtained to confirm the position of the needle. The needle is then advanced using a loss of resistance syringe filled with 1ml of air or normal saline. As the needle passes the ligamentum flavum and enters the posterior epidural space, a sudden loss of resistance will occur allowing the syringe to inject a minimal amount of air or normal saline into epidural space due to the change in pressure. The loss of resistance syringe is then replaced with a syringe filled with the contrast solution, which is then injected to confirm placement of the needle in the epidural space. Once spread of contrast is confirmed in AP and lateral views, steroid (e.g., methylprednisolone, triamcinolone, betamethasone or dexamethasone) with or without local anesthetic is injected into epidural space. Finally, the needle is then withdrawn, and pressure is maintained at the injection site to prevent bleeding.
Transforaminal Epidural Steroid Injection (lateral approach)
With the patient lying prepped and in a prone position, the lateral foraminal space between two contiguous vertebrae is identified via an oblique view on fluoroscopic x-ray. This view displays the classic “Scottie dog,” an anatomical landmark used for needle guidance. Once proper injection site is identified, the skin and underlying tissue are injected with local anesthetic (e.g., lidocaine or bupivacaine). An epidural spinal needle is then inserted and directed under the pedicle of the superior vertebrae. A lateral view on x-ray is obtained to determine needle depth and to prevent damage to the nerve root. The needle is then advanced until it reaches the outer intervertebral foramen. Contrast injection confirms needle position in both lateral and AP views displaying epidural spread. Steroid (e.g., dexamethasone) with or without local anesthetic is then injected into the epidural space. Finally, the needle is withdrawn, and pressure is maintained at the injection site to prevent bleeding.
Caudal Epidural Steroid Injection
With the patient lying prepped and in a prone position, the sacral hiatus is identified via an AP view on fluoroscopic x-ray. Once proper injection site is identified, the skin and underlying tissue are injected with local anesthetic (e.g., lidocaine or bupivacaine). An epidural spinal needle is then inserted and directed through the sacral hiatus. A lateral view on x-ray is obtained to determine needle depth. Needle placement below the S2-3 intervertebral disc space will decrease the risk of dural puncture. Contrast injection confirms needle position in both lateral and AP views displaying epidural spread. The steroid is then injected into the epidural space. Finally, the needle is withdrawn, and pressure is maintained at the injection site to prevent bleeding.
Although rare, possible complications include:
When performed by a skilled physician, epidural steroid injections are a safe and integral treatment of back and leg or neck and arm pain caused by multiple conditions. It is imperative to note that epidural steroid injections are not necessarily designed to cure back or neck pain, instead, they are intended to provide temporary relief so that the patient may return to normal activities and/or continue their physical therapy regimen. Pain relief from epidural steroid injections may vary from one week to one year, and patients may require either a single or a series of injections for maximum relief.
While epidural steroid injections are widely performed. it is important to educate the patient that the response is not immediate, nor do these drugs provide pain relief in everyone.[21] Thus, the primary care provider, nurse practitioner and orthopedic nurse should educate the patient on lifestyle changes such as regular exercise, discontinuing smoking, maintaining a healthy weight and avoiding a sedentary lifestyle.
The outcomes after epidural steroids are good but unpredictable. The injections do not usually cure the back pain but do help improve the quality of life for some time. [8][22]
[1] | Jain S,Malinowski M,Chopra P,Varshney V,Deer TR, Intrathecal drug delivery for pain management: recent advances and future developments. Expert opinion on drug delivery. 2019 Aug; [PubMed PMID: 31305165] |
[2] | Al Khalili Y,Jain S,Murphy PB, Cervicogenic Headache 2020 Jan; [PubMed PMID: 29939639] |
[3] | Akuthota V,Meron AJ,Singh JR,Boimbo S,Laker SR,Brakke R,Sridhar BV,Friedrich J,Sullivan WJ, The Utility of MRI Results in Physician Decision Making Prior to Initial Lumbar Spinal Injection. The spine journal : official journal of the North American Spine Society. 2019 Apr 19; [PubMed PMID: 31009770] |
[4] | Golubovsky JL,Momin A,Thompson NR,Steinmetz MP, Understanding quality of life and treatment history of patients with Bertolotti syndrome compared with lumbosacral radiculopathy. Journal of neurosurgery. Spine. 2019 Apr 19; [PubMed PMID: 31003219] |
[5] | Arici T,Kurçaloğlu M,Eyıgor C,Uyar M, Transforaminal epidural steroid injection and infraneural approach. Agri : Agri (Algoloji) Dernegi'nin Yayin organidir = The journal of the Turkish Society of Algology. 2019 Apr; [PubMed PMID: 30995325] |
[6] | Taşdemir BB,Aydın ON, [A retrospective investigation of the efficiency of transforaminal anterior epidural steroid injections in patients with low back pain and the effects of interventional pain therapy on quality of life]. Agri : Agri (Algoloji) Dernegi'nin Yayin organidir = The journal of the Turkish Society of Algology. 2019 Apr; [PubMed PMID: 30995324] |
[7] | Mathews S,Jain S, Anatomy, Head and Neck, Cricoid Cartilage 2020 Jan; [PubMed PMID: 30969643] |
[8] | Alvin MD,Mehta V,Halabi HA,Lubelski D,Benzel EC,Mroz TE, Cost-Effectiveness of Cervical Epidural Steroid Injections: A 3-Month Pilot Study. Global spine journal. 2019 Apr; [PubMed PMID: 30984492] |
[9] | Huang R,Meng Z,Cao Y,Yu J,Wang S,Luo C,Yu L,Xu Y,Sun Y,Jiang L, Nonsurgical medical treatment in the management of pain due to lumbar disc prolapse: A network meta-analysis. Seminars in arthritis and rheumatism. 2019 Mar 4; [PubMed PMID: 30940466] |
[10] | Vydra D,Hynes A,Clements N,Nagpal A,Julia J,Schneider BJ,Maus TP,Cushman DM,McCormick ZL, Current Practice Trends in Image Guidance During Lumbar and Cervical Transforaminal Epidural Steroid Injections. Pain medicine (Malden, Mass.). 2019 Apr 2; [PubMed PMID: 30938803] |
[11] | Manchikanti L,Buenaventura RM,Manchikanti KN,Ruan X,Gupta S,Smith HS,Christo PJ,Ward SP, Effectiveness of therapeutic lumbar transforaminal epidural steroid injections in managing lumbar spinal pain. Pain physician. 2012 May-Jun [PubMed PMID: 22622912] |
[12] | Manchikanti L,Knezevic NN,Boswell MV,Kaye AD,Hirsch JA, Epidural Injections for Lumbar Radiculopathy and Spinal Stenosis: A Comparative Systematic Review and Meta-Analysis. Pain physician. 2016 Mar [PubMed PMID: 27008296] |
[13] | Kennedy DJ,Zheng PZ,Smuck M,McCormick ZL,Huynh L,Schneider BJ, A minimum of 5-year follow-up after lumbar transforaminal epidural steroid injections in patients with lumbar radicular pain due to intervertebral disc herniation. The spine journal : official journal of the North American Spine Society. 2018 Jan [PubMed PMID: 28962912] |
[14] | Singh JR,Cardozo E,Christolias GC, The Clinical Efficacy for Two-Level Transforaminal Epidural Steroid Injections. PM & R : the journal of injury, function, and rehabilitation. 2017 Apr [PubMed PMID: 27614187] |
[15] | Deer TR,Grider JS,Lamer TJ,Pope JE,Falowski S,Hunter CW,Provenzano DA,Slavin KV,Russo M,Carayannopoulos A,Shah JM,Harned ME,Hagedorn JM,Bolash RB,Arle JE,Kapural L,Amirdelfan K,Jain S,Liem L,Carlson JD,Malinowski MN,Bendel M,Yang A,Aiyer R,Valimahomed A,Antony A,Craig J,Fishman MA,Al-Kaisy AA,Christelis N,Rosenquist RW,Levy RM,Mekhail N, A Systematic Literature Review of Spine Neurostimulation Therapies for the Treatment of Pain. Pain medicine (Malden, Mass.). 2020 Feb 8 [PubMed PMID: 32034422] |
[16] | Deer TR,Jain S,Hunter C,Chakravarthy K, Neurostimulation for Intractable Chronic Pain. Brain sciences. 2019 Jan 24 [PubMed PMID: 30682776] |
[17] | Hashizume K,Fujiwara A,Watanabe K,Kamihara M,Iwasaki S,Yamagami H, A Prospective Comparison of CT-Epidurogram Between Th1-Transforaminal Epidural Injection and Th1/2-Parasagittal Interlaminar Epidural Injection for Cervical Upper Limb Pain. Pain physician. 2019 Mar; [PubMed PMID: 30921982] |
[18] | Lee JH,Sim KC,Kwon HJ,Kim JW,Lee G,Cho SS,Choi SS,Leem JG, Effectiveness of lumbar epidural injection in patients with chronic spinal stenosis accompanying redundant nerve roots. Medicine. 2019 Mar; [PubMed PMID: 30817564] |
[19] | Przkora R,Kinsky MP,Fisher SR,Babl C,Heyde CE,Vasilopoulos T,Kaye AD,Volpi E, Functional Improvements Utilizing the Short Physical Performance Battery (SPPB) in the Elderly after Epidural Steroid Injections. Current pain and headache reports. 2019 Feb 22; [PubMed PMID: 30796532] |
[20] | Tubben RE,Jain S,Murphy PB, Epidural Blood Patch . 2020 Jan [PubMed PMID: 29493961] |
[21] | Jani P,Morley HL,Shetty N, Iatrogenic adrenal suppression following caudal epidural and facet joint injection. BMJ case reports. 2019 Feb 21; [PubMed PMID: 30796074] |
[22] | Duszynski B, Spine Intervention Society Position Statement on Best Practices for Epidural Steroid Injections in the Setting of a Preservative-Free Dexamethasone Shortage. Pain medicine (Malden, Mass.). 2019 Apr 29; [PubMed PMID: 31034052] |