Myofascial Block

What is myofascial pain and what are its symptoms?

On many occasions, especially in patients with chronic back pain, the origin of the pain may be myofascial.

We define myofascial syndrome as pain whose origin is in the skeletal muscle and which has the following characteristics:

• Pain in a neighboring area, and referred to the affected muscle with a specific pattern for each muscle.
• Existence of trigger points (TP), a palpable and hyperirritable nodule located in a tense band of the muscle. When this point is stimulated, two characteristic phenomena occur: the appearance of referred pain and the production of an abrupt motor activity in the tense band.
• Shortening of the muscle fiber that will produce a restriction in the normal mobility of the muscle associated with adhesions between the muscle fasciae.

When conservative treatment has failed, the possibility of mitigating pain by infiltration of the trigger point associated with a blockade of the muscle fasciae is a valid therapeutic alternative in appropriately selected patients.

The muscles most frequently responsible for chronic pain are the trapezius, latissimus dorsi and thoracolumbar fascia, quadratus lumborum, piriformis muscle and psoas.

What is ultrasound-guided blockade in myofascial pain?

After applying general sterility measures and using a suitable probe, the best image of the anatomical area generating pain is obtained. The ultrasound-guided puncture is then performed, visualizing in real time the needle and the diffusion of the drug in the pain-generating muscle.

• Trapeze locking
  It is the most important muscle of the cervical area, participating in the extension of the cervical and dorsal spine, and in the cervical lateralization movements, as well as in the extreme movements of the scapula and shoulder. Trapezius myofascial syndrome is common after traffic accidents with whiplash, and in post-surgical neck pain syndromes. It manifests with pain in the cervical area, often accompanied by occipital headache and contracture.

  The muscle block is performed by localizing the cervical fascia and the muscle with its trigger points. Using ultrasound, we located the trapezium immediately below the subcutaneous fatty tissue (Fig. 1). Ultrasound allows us to correctly visualize the pleura when performing punctures in the middle and lower trapezius (Fig. 2), thus avoiding the production of a pneumothorax, one of the most serious complications when performing this technique.

• Block of the latissimus dorsi and thoracolumbar fascia
  It is the largest, widest and strongest muscle of the trunk. It is located posterior to the arm. It begins its insertions covered by the trapezium, at the apex of the spinous processes of the last thoracic vertebrae; continuing along the midline to the median sacral crest, and laterally, to the iliac crest and the external face of the four lower ribs. It is a muscle that allows adducting and rotating the arm as well as elevating the trunk and at the same time the last four ribs.

  It also participates in the stabilization of the pelvis and in the extension of the dorsolumbar spine together with the erector spinae muscle (with which it has continuity thanks to the thoracolumbar fascia), which is why a myofascial syndrome of the latissimus dorsi is often identified in chronic dorsalgias. The latissimus dorsi muscle block is performed by ultrasound localization of the thoracolumbar fascia and trigger points in the muscle. Ultrasound also allows us to identify the erector spinae muscle and the pleura.

• Quadratus lumborum block
  Myofascial syndrome of the quadratus lumborum muscle is one of the most frequent causes of low back pain of muscular origin. It is the muscle that plays a major role in the maintenance of upright posture, and contributes to the extension and lateralization movements of the lumbar spine. The quadratus lumborum muscle originates in the iliolumbar ligament and iliac crest, and inserts in the transverse processes.

  Thanks to ultrasound we visualize the quadratus lumborum muscle below the lower border of the 12th rib, between the transverse processes from L1 to L4. The shadow of the lower pole of the kidney appears with the respiratory movements, and above it, the muscular mass of the quadratus lumborum appears (fig.3), locating then, the insertion of the muscle in the iliac crest where we will proceed to the block.

• Piriformis muscle block
  Muscle capable of causing referred pain in the lower back and back of the thigh. It is a small muscle located deep within the hip and gluteal region. It has its insertions in the sacrum (the lowest region of the spine), and in the femur (thigh bone). Its primary function is external rotation of the hip.
  Myofascial syndrome of the piriformis or piriformis is usually caused by a contracture or spasm, which irritates the sciatic nerve as it passes underneath.

  Its contracture causes pain in the gluteal region and may even result in referred pain in the posterior and distal thigh. Patients often report deep pain from the hip to the buttocks.

  The ultrasound localization of the piriformis is not complex. We will locate the femoral head, drawing a triangle between the gluteus maximus above, the iliac bone below, and the femoral head on the outside where the piriformis muscle is located (Fig. 4-5).

• Psoas block
  It is a muscle that participates little in lumbar mobility, its main function is hip flexion. However, as they originate in the lateral aspect of the lumbar vertebrae and discs, their contracture can produce lumbar pain. As it is deep, it is only accessible by palpation in the insertion area, and in its course through the abdomen, places where we can find active trigger points.

  The ultrasound view of the psoas is not easy due to its deep location and covered by bony structures, such as the transverse processes of the lumbar vertebrae, and by the vertebral bodies that overshadow the area of the muscle. Placing the ultrasound probe parallel to the axis of the spine at lumbar level. Between the transverse processes we will find the psoas and the area where we can block it.

What are the risks of myofascial blockade?

Complications associated with myofascial blockade are rare and are usually self-limited. Occasionally, there may be a sudden and intense increase in pain in the injected area, which is usually transient and controlled with anti-inflammatory or analgesic medication.
In some people sensitive to pain or to the sight of blood, vasovagal syncope occurs, a dizziness accompanied by a feeling of heat, sweating and fainting sensation. It is not serious and subsides with Atropine.
Pneumothorax is a very rare but serious complication, which can occur during injection in the trapezius or latissimus dorsi. The use of ultrasound allows us to visualize the pleura minimizing this possibility.
Another unusual complication is the formation of a hematoma at the puncture site.

From the Rehabilitation Medicine and Complementary Therapies Unit at Barcelona Spine Institute we offer our patients the most appropriate personalized treatment. Do not hesitate to contact your specialist and request an appointment.