Lidocaine Trigger Point Injections
When myofascial pain is a component of the pain problem, a trigger point injection is helpful in treatment, but only after the patient demonstrates ability and compliance with the home stretching protocol.
These injections are used to treat extremely painful areas of muscle that do not respond to stretching. A trigger point is a knot or tight, ropy band of muscle that forms when a muscle fails to relax. The knot often can be felt under the skin.
Related Reading: How to Diagnose Masticatory Muscle Disorders
How it Works
Usually a small needle is inserted into the trigger point and a local anesthetic is used (0.5 cc of 0.5% or 1% lidocaine). This injection inactivates the trigger point and thus alleviates pain. Numbness from the anesthetic may last about an hour, and a bruise may form at the injection site but this is not common.
Pain can be relieved by alternately applying moist heat and ice for a day or two. In all cases, stretching exercises are performed following TP injections. The patient should contact the physician if redness or swelling develops. There is some risk for puncturing a lung or the membrane that surrounds the lung (called the pleura) when a muscle near the ribcage receives a trigger point injection.
Diagnoses that Link with Lidocaine Injections
- MFP with an “active” trigger point
- Active trigger point is defined as a pain site within a taut muscle band with referred pain on palpation
- Referred pain should be elicited by compression of the trigger point for 3 seconds producing pain in a referred but nearby site
Related Reading: TMJ Manipulation & Mobilization Treatments
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Steroid Injections for the TMJ
A TMJ joint injection is not the first approach for joint pain and swelling because it is logical to first try NSAIDs for a couple of weeks. However, if this medication or self-treatment approach fails to yield an improvement in two weeks, the next procedure to be considered would be a local anesthetic/corticosteroid assisted mobilization of the TM joint.
This procedure can be done at an outpatient office visit, when a combination anesthetic and steroid injection is administered to the joint, the jaw is manually mobilized (stretched open gently) to increase mobility, or the patient is taught self-stretching exercises to be performed at home.
Intra-articular injections are occasionally used as a both diagnostic and therapeutic purposes of TM Joint pain. The primary indication for this procedure is substantial tenderness of the joint capsule.
Conduct the procedure by anesthetizing the joint with 2% lidocaine (without epinephrine) and perform a joint lavage and intracapsular steroid injection with triamcinolone acetonide (Kenalog-40). Usually, a corticosteroid injection in a small joint such as the TMJ is not performed more frequently than 10 times total and no more than once every three months (maximum of four injections a year).
Diagnoses that Link with Steroid Injections
- An arthritis/capsulitis flare-up of the TMJ with pain being generated on function
- TMJ capsule palpation should reveal substantial tenderness that has not responded to NSAIDs
- A recent onset painful DDNR disorder
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Hyaluronate Injection for the TM Joint
In cases where the patient has a substantial friction related joint dysfunction (e.g. frequent painful clicking, episodic closed or open locking and/or a recent onset painful crepitation), a method to treat is injecting an artificial joint fluid. The agent is essential hyaluronic acid, which is a naturally occurring lubricating chemical that is present in all synovial joints.
The first line of treatment is avoidance of motion and NSAIDs for a couple of weeks. If this approach fails to yield an improvement in two weeks, the next procedure to be considered would be an injection of 1 ml (1 cc) hyaluronic acid into the TMJ superior joint space.
The commercial products that are used for these two are Hyalgan or Synvisc. Either product can be helpful, and the injection is usually involving two injections spaced three to four weeks apart. This procedure can be done at an outpatient office visit.
Diagnoses that Link with Hyaluronate Injections
- DDWR (frequent, unavoidable pain after using avoidance therapy)
- Episodic DDNR, which is frequent and resistant to avoidance therapy
- TMJ osteoarthritis with painful, frequent, and unavoidable crepitation
Related Reading: Internal Derangements of the Temporomandibular Joint
Botulinum Toxin Type A (BotNa) Injections
Botulinum toxin is known as a blocker of exocytosis of neurotransmitters; it prevents vesicles which contain neurotransmitters (found inside a nerve) from binding with the nerve cell wall membrane and releasing the contents of the vesicle into the synaptic cleft.
In the case of motor nerves, this toxin blocks the release of acetylcholine, a neurotransmitter which induces muscle contraction. When injected into a muscle, the toxin finds the motor nerves, blocks exocytosis, and thus reduces the ability of the muscle to contract.
When botulinum toxin is injected near a motor end plate, where a trigger point would develop, this reduces the motor nerves ability to drive a sustained taut band in the muscle. Over time, if these taut bands are reduced, the accumulation of metabolic waste in the area of the band is reduced and the sensitized c-fibers nerves would “desensitize”. Therefore, botulinum toxin is used as a treatment for persistent taut bands in myofascially altered muscles.
Disadvantages
The disadvantage of this method is that the use of local anesthetic injections into trigger points is actually a more substantial, but shorter acting way of relieving the trigger point pain than botulinum toxin. Thus, the first line therapy for a trigger point is stretch and thermal therapy. The second approach is local anesthetic trigger point injections. The third is botulinum toxin trigger point injections.
Diagnoses that Link with Botox Treatments
- Myofascial pain with an “active” trigger point that is unresponsive to trigger point injection treatment
- Active trigger point is defined as a pain site within a taut muscle band with referred pain on palpation
- Referred pain should be elicited by compression of the trigger point for 3 seconds, producing pain in a referred but nearby site
TMJ Arthrocentesis
Arthrocentesis is indicated in those patients who do not improve with anesthesia assisted joint mobilization. The primary goal of this procedure is to lavage the joint space to remove inflammatory by-products in the joint and attempt to mobilize the TM Joint.
This procedure involves lavage and mobilization of the joint under sedation. Joint pumping with a single needle or the double needle technique dubbed “arthrocentesis” does not require the patient to be sedated to do either procedure. It is, however, usually desirable since these procedures are more complex and the needle is substantially larger than those used for simple anesthesia of the joint.
After the lavage, the jaw is typically manually mobilized to see if increased opening is possible. This lavage or mobilization procedure is called an arthrocentesis assisted joint manipulation. It is not expected that the displaced disc will be reduced by this procedure. Only that the jaw will have increased motion.
Arthrocentesis Procedure
- Anesthetize the cutaneous tissues overlying the joint capsule, and block of the auriculotemporal nerve with a long-acting local anesthetic (2% lidocaine).
- Place two 20 gauge needles into the joint and infuse into the superior joint space with 300 cc’s of lactated ringers solution.
- Manually manipulate the TM Joint, pulling it down and forward in an attempt to mobilize the disc that is not moving properly.
- Assuming a successful manipulation, infuse a long acting corticosteroid solution into the superior joint space.
- Prescribe analgesic for the next 2-3 days and apply ice packs to the TMJ for the first two hours post-op.
- Re-examine the patient one month after the surgery, and if they still have pain symptoms, manage appropriately with medication.
Diagnoses that Link with an Arthrocentesis Procedure
- Recent onset painful DDNR disorder (see DDNR for criteria)
- Patient has not responded to or wouldn’t allow a joint injection and mobilization without sedation
- Examination of active opening equals an internal distance of <35mm.
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