Trigger Point Injections (TPIs) are a common treatment used to manage chronic muscle pain associated with myofascial pain syndrome. A trigger point is a hyperirritable spot or “muscle knot”—a small, taut band of muscle fiber and its surrounding fascia that is painful when pressed. These localized areas of tension can cause restricted movement and referred pain in distant body parts. For many people considering this treatment, the primary concern is the discomfort involved, and understanding the sequence of sensations provides a clear roadmap of what to expect during the quick procedure.
Understanding the Sensation During Injection
The discomfort experienced during a TPI is typically concentrated into a few brief moments and is generally well-tolerated by most patients. The first sensation is a sharp, momentary pinch as the ultra-thin needle penetrates the skin’s surface. This initial feeling is comparable to receiving a standard vaccination and subsides almost immediately. The injection solution frequently contains a local anesthetic like lidocaine, which begins to numb the superficial tissue quickly.
The most distinct feeling occurs when the needle tip reaches the trigger point itself, which is the taut, contracted band of muscle fiber. This contact often elicits a brief, intense deep ache, pressure, or cramping sensation. This temporary discomfort is often accompanied by a localized muscle spasm known as a “local twitch response,” where the muscle visibly contracts under the skin.
Practitioners view the twitch response as confirmation that the needle is precisely targeting the hyperirritable tissue. This brief increase in pain is a positive sign, indicating the necessary mechanical disruption required to deactivate the knotted fibers. The sensation is short-lived because the practitioner immediately follows this with the injection of the solution.
As the medication is delivered, patients may feel a sensation of fullness, pressure, or a mild burning as the liquid disperses within the muscle tissue. When a local anesthetic is used, this is quickly replaced by a spreading feeling of numbness or heaviness in the area. The entire process of needle insertion, trigger point contact, and injection is incredibly fast, often taking only seconds per point. The temporary discomfort is often considered a fair trade-off against the potential for sustained relief from chronic myofascial pain.
What Happens During the Appointment
The appointment begins with a brief review of the affected areas and symptoms to confirm the best treatment strategy. The practitioner then physically examines the muscle, using their fingers to palpate and locate the specific, hypersensitive nodule or taut band that constitutes the trigger point. This manual identification step is important for ensuring accurate needle placement.
The patient is positioned comfortably, typically sitting or lying down, to allow easy access to the muscle being treated. Once the trigger point is located, the skin over the target area is thoroughly cleansed with an antiseptic solution to minimize any risk of infection.
To prevent the muscle knot from slipping away during the procedure, the practitioner often uses two fingers to pinch and stabilize the trigger point. This stabilization ensures the thin needle is precisely directed into the intended muscle fiber, increasing the likelihood of successfully deactivating the muscle knot.
The practitioner inserts the needle and may perform a technique called “pistoning” or “needling,” where the needle is inserted and slightly withdrawn repeatedly without fully removing it from the skin. This mechanical action is intended to break up the contracted muscle fibers and continues until the local twitch response ceases or the muscle tension feels adequately released. Each individual trigger point injection is completed within a minute.
After the mechanical disruption, the medication—usually a local anesthetic, often combined with saline or sometimes a corticosteroid—is injected into the deactivated site. The anesthetic provides immediate pain relief, while the other agents help reduce inflammation and promote muscle relaxation. A small bandage is applied, and the patient is typically cleared to move immediately afterward.
Immediate Post-Procedure Care and Relief Expectation
Immediately following the injection, the treated area will likely feel numb or heavy due to the local anesthetic, which can last for several hours. Patients are advised to avoid strenuous activity, heavy lifting, or intense exercise for the first 24 to 48 hours. Gentle movement and light activities, such as walking, are encouraged to prevent the muscle from becoming stiff and to promote healing.
Once the anesthetic wears off, it is common to experience a temporary increase in soreness, tenderness, or a dull ache at the injection site. This post-injection discomfort is a normal reaction to the physical trauma of the needle and the mechanical needling of the muscle tissue. Mild bruising and slight swelling are also common side effects that typically resolve within a few days.
Managing Post-Injection Discomfort
To manage discomfort, applying an ice pack to the area for 15 to 20 minutes can help reduce inflammation and soreness during the first 24 hours. After this initial period, some practitioners recommend switching to moist heat to promote blood flow and further muscle relaxation. Over-the-counter pain relievers, such as acetaminophen, are often recommended. Non-steroidal anti-inflammatory medications may be advised against initially due to the potential for increased bruising.
The timeline for achieving sustained pain reduction varies among individuals. Many notice immediate relief from the anesthetic component. Deeper pain relief from the deactivation of the trigger point usually manifests within 24 to 72 hours, once the initial post-injection soreness subsides. This period allows the muscle to fully relax and the inflammation to decrease, often leading to improved range of motion and function.
When to Contact a Professional
While complications are uncommon, patients should be vigilant for signs that require medical attention. Contact the treating professional if you experience any of the following:
- Severe pain that worsens significantly after the initial 72 hours.
- Excessive redness, warmth, or drainage from the injection site.
- A fever.
- New, persistent numbness or weakness.