Medial branch block injections are safe and well-tolerated by most patients. 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051

As with any injection procedure, there are potential risks, but the side effects are typically minor and transient, and serious complications are rare. 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051 , 2 Le DT, Alem N. Facet Joint Injection. [Updated 2023 Jun 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572125/

In This Article:

Potential Side Effects of Medial Branch Blocks

Medial branch block injections typically cause mild and temporary localized side effects, such as 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051 :

  • Pain and soreness
  • Numbness
  • Weakness in the arms and/or legs
  • Bleeding and/or bruising
  • Vasovagal reactions (slow heart rate, sweating, and dizziness)

If corticosteroids are used, temporary flushing, headache, increased injection site pain (also called “steroid flare"), and agitation may occur in some cases. 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051 , 3 Alsop RJ, Khondker A, Hub JS, Rheinstädter MC. The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations. Sci Rep. 2016;6:22425. Published 2016 Mar 3. doi:10.1038/srep22425

The recommended treatments for these temporary effects include the application of ice and/or over-the-counter pain medications (eg, Tylenol and Advil). 

See Medications for Back Pain and Neck Pain

Avoiding the use of pain medication for the first 4 to 6 hours after the injection is recommended to ensure an accurate assessment of the procedure's effectiveness.

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Potential Risks and Adverse Events of Medial Branch Blocks

The complications associated with medial branch block injection procedures are primarily related to incorrect needle placement and/or sensitivity to the medications used, and include 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051 , 2 Le DT, Alem N. Facet Joint Injection. [Updated 2023 Jun 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572125/ :

  • Excessive bleeding and bruising
  • Infection
  • Allergic reaction to medication or contrast dye
  • Worsening of pain
  • Nerve damage, including permanent weakness of the arms and/or legs
  • Spinal cord damage or paralysis

When imaging is used, the risks of nerve injury and inadvertent injection of medication into nearby blood vessels, nerves, or tissue are low. 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051 , 2 Le DT, Alem N. Facet Joint Injection. [Updated 2023 Jun 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572125/

Potential risks of corticosteroid use in medial branch block injections

Corticosteroids used in therapeutic blocks carry a risk of significant complications due to the potential for absorption into the bloodstream, including 4 Stout A, Friedly J, Standaert CJ. Systemic Absorption and Side Effects of Locally Injected Glucocorticoids. PM R. 2019;11(4):409-419. doi:10.1002/pmrj.12042 :

  • Osteonecrosis
  • Decreased bone mineral density
  • Reproductive hormone imbalance
  • Psychiatric changes (eg, agitation, irritability, insomnia)
  • Increased blood sugar (hyperglycemia)
  • High blood pressure (hypertension)
  • Fluid retention
  • Adrenal suppression

Additionally, chronic exposure to corticosteroids from repeated therapeutic blocks and/or the presence of underlying medical conditions (eg, diabetes, osteoporosis, and heart disease) increases the risk of serious adverse events. 3 Alsop RJ, Khondker A, Hub JS, Rheinstädter MC. The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations. Sci Rep. 2016;6:22425. Published 2016 Mar 3. doi:10.1038/srep22425

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Long-term risks of medial branch block injections

In some cases, nerve injury and/or untreated infections may cause permanent damage, but these complications are rare. 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051 , 2 Le DT, Alem N. Facet Joint Injection. [Updated 2023 Jun 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572125/

It is advisable to discuss the risks, benefits, and alternative treatments with your doctor before proceeding with medial branch block injections.

  • 1 Carr CM, Plastaras CT, Pingree MJ, et al. Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study. Pain Medicine. 2016;17(12):2155-2161. doi: 10.1093/pm/pnw051
  • 2 Le DT, Alem N. Facet Joint Injection. [Updated 2023 Jun 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572125/
  • 3 Alsop RJ, Khondker A, Hub JS, Rheinstädter MC. The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations. Sci Rep. 2016;6:22425. Published 2016 Mar 3. doi:10.1038/srep22425
  • 4 Stout A, Friedly J, Standaert CJ. Systemic Absorption and Side Effects of Locally Injected Glucocorticoids. PM R. 2019;11(4):409-419. doi:10.1002/pmrj.12042

Dr. Yash Mehta is a board-certified, fellowship-trained physiatrist at Virginia Spine Institute, VA.

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