Periradicular therapy (PRT) is a common, minimally invasive procedure used to treat specific types of spinal pain. The term “periradicular” means “around the nerve root,” which describes the target of the treatment. This technique involves injecting medication directly into the space surrounding an irritated spinal nerve root as it exits the vertebral column. PRT is an interventional pain management approach, often utilized when conservative treatments, like oral medication or physical therapy, have failed to provide lasting relief. The procedure delivers a potent anti-inflammatory agent to the exact site of inflammation, reducing swelling and alleviating pain caused by nerve compression.
Causes of Nerve Root Pain Treated by PRT
Periradicular therapy is specifically indicated for radicular pain, which is nerve pain that travels away from the spine along the path of a nerve root, commonly known as sciatica in the lower back. This radiating pain occurs when the nerve root is physically compressed, chemically irritated, or inflamed as it leaves the spinal canal through a small opening called the neural foramen. The underlying conditions that cause this compression are generally mechanical or degenerative.
One of the most frequent causes is a herniated disc, where the soft inner material pushes out and impinges directly on the nearby nerve root. This physical pressure often combines with chemical irritation from inflammatory substances released by the damaged disc material.
Another common cause is spinal stenosis, a degenerative narrowing of the spinal canal or the neural foramen. This narrowing is often a result of age-related wear and tear, leading to the formation of bone spurs (osteophytes) and thickening of spinal ligaments, which gradually constrict the space around the nerve root.
Other conditions like spondylolisthesis, where one vertebra slips forward over another, or scar tissue formation after previous spine surgery can also lead to nerve root compression.
The Periradicular Injection Process
The periradicular injection process is a precise, outpatient procedure that relies on advanced imaging guidance to ensure accurate medication delivery. The patient is typically positioned on the procedure table, and the skin over the treatment area is thoroughly cleansed and disinfected. Local anesthetic is injected into the skin and underlying tissues to minimize discomfort.
The physician uses imaging technology, most commonly fluoroscopy (live X-ray) or computed tomography (CT) guidance, to visualize the patient’s spinal anatomy in real-time. This imaging allows the doctor to safely guide a thin needle near the targeted, inflamed nerve root, avoiding delicate structures like blood vessels and the spinal cord.
Once the needle is confirmed to be in the correct periradicular location, a small amount of contrast dye is often injected. The contrast material confirms the precise placement and ensures the medication will flow into the intended area, also helping rule out placement into a blood vessel.
The therapeutic medication mixture is then injected, which includes both a local anesthetic and a powerful anti-inflammatory corticosteroid preparation. The local anesthetic provides immediate, temporary pain relief and serves as a diagnostic confirmation. The corticosteroid is the primary agent for long-term relief, working to reduce the inflammation and swelling of the irritated nerve root over the following days and weeks.
Post-Procedure Recovery and Pain Management
Following the periradicular injection, patients are typically monitored for a short observation period, usually about 30 minutes, before being discharged. Due to the temporary numbing effects of the local anesthetic, which can cause transient leg or arm weakness, patients are advised not to drive for the remainder of the day.
It is common to experience immediate pain relief from the anesthetic, which may wear off after a few hours, causing the pain to return briefly. The longer-lasting pain relief from the corticosteroid generally begins to be noticeable within two to seven days, though maximum benefit may take up to two weeks.
Some patients may experience minor soreness or discomfort at the injection site for a day or two, which can usually be managed with over-the-counter pain relievers. If the pain is significantly reduced, the effect may last for several months.
If the initial injection provides good but incomplete relief, or if the pain returns after a few months, a series of one to three injections spaced several weeks apart may be recommended. PRT is often integrated with a physical therapy program to strengthen core muscles and improve spinal mechanics. Patients should contact their doctor immediately if they experience new or worsening numbness, significant muscle weakness, fever, or signs of infection at the injection site, although serious complications are rare.