MYOFASCIAL PAIN IN THE SPINE

The origin of back pain is often myofascial, especially in patients with chronic back pain.

Myofascial pain syndrome is defined as any pain originating in a skeletal muscle and which has the following characteristics:

Pain in a neighbouring area, referred to the affected muscle with a specific pattern for each muscle.
Trigger points – palpable and hyperirritable nodules located in taut bands of muscle. When these points are stimulated, two characteristic phenomena occur: the onset of referred pain and the production of sudden motor activity in the taut muscle band.
Shortening of the muscle fibre which will restrict the normal mobility of the muscle associated with adhesions between muscle fasciae.

ULTRASOUND-GUIDED TREATMENT OF MYOFASCIAL PAIN IN THE SPINE

Treatment of myofascial pain starts by locating the painful muscle using the patient’s medical history and a physical examination.

Treatment for myofascial pain syndrome aims to inactivate the trigger points and elongate the muscle up to its normal length.

Classic myofascial treatment consists of physiotherapy techniques (such as stretching with intermittent cold) combined with pharmacotherapy for the chronic pain (analgesics and psychotropic drugs).

Many useful rehabilitation procedures have been described, from massages (deep friction massage, compression) to stretches with myofascial release techniques.

Several types of electrotherapy have also been used with modest results (ultrasound, TENS and interferential currents, repetitive magnetic stimulation, galvanisation, laser and iontophoresis).

If conservative treatment fails, alleviating the pain by injection into the trigger point to produce a a muscle fascia block is a valid therapeutic alternative in suitable patients.

ULTRASOUND-GUIDED BLOCKS IN MYOFASCIAL PAIN

tratamiento ecoguiado dolor miofascial ECOGUIADA Dra. Paola Cavasin Barcelona Spine Institute unidad columna

Applying general sterility measures and using a suitable probe, the best possible picture is obtained of the anatomical area where the pain originates. Then the needle is inserted with ultrasound guidance, enabling the needle and the diffusion of the drug into the pain-generating muscle to be viewed in real time.

Complications associated with myofascial blocks are rare and tend to be self-limiting. There may occasionally be sudden, intense increases in pain in the area injected, but these are usually transient and can be controlled by anti-inflammatory or analgesic medication.

In some people who are sensitive to pain or the sight of blood, it can cause vasovagal syncope; dizziness accompanied by a sensation of heat, sweating and light-headedness. This is not serious and can be alleviated with atropine.

Collapsed lung is a rare but serious complication that can occur during injection into the trapezius muscle or the latissimus dorsi. The use of ultrasound enables the pleura to be visualised, which minimises this possibility.

Another unusual complication is the formation of a haematoma at the injection site.

MYOFASCIAL BLOCKS

Chronic pain most often originates in the following muscles:

TRAPEZIUS

This is the most important muscle in the upper back area. It is involved in extension of the upper and thoracic spine, and in lateral neck movements, as well as in extreme movements of the scapula and shoulder. Myofascial pain syndrome of the trapezius muscle is common after traffic accidents involving whiplash, and post-surgical neck pain syndromes. Symptoms include pain in the upper back area, often accompanied by occipital headache and contracture.

The muscle is blocked by locating the cervical fascia and the muscle with its trigger points. Ultrasound is used to locate the trapezius immediately below the subcutaneous fat layer (Fig. 1). The ultrasound enables the pleura to be visualised clearly when the needle is inserted into the middle or lower trapezius (Fig. 2), preventing lung collapse, which is one of the most serious possible complications when performing this technique.

LATISSIMUS DORSI AND THORACOLUMBAR FASCIA

Anatomical drawing of the latissimus dorsi muscle

This is the largest, widest and strongest muscle in the torso and it is located behind the arm. It starts its insertion covered by the trapezius, at the apex of the spinous processes of the last thoracic vertebrae, and continues down the midline to the median sacral crest, and laterally, to the iliac crest and the outer side of the four lower ribs. This is the muscle that enables you to adduct and rotate your arm, and to raise your torso and the last four ribs.

It is also involved in stabilising the pelvis and extending the dorsolumbar spine and erector spinae muscles (to which it is attached by means of the thoracolumbar fascia). Consequently, myofascial pain syndrome in chronic back pain often occurs in the latissimus dorsi. Ultrasound is used to locate the thoracolumbar fascia and the trigger points in the muscle to block the latissimus dorsi muscle. Ultrasound also enables us to identify the erector spinae muscles and the pleura.

QUADRATUS LUMBORUM

Myofascial pain syndrome in the quadratus lumborum muscle is one of the most common causes of muscular lower back pain. It is the muscle that has the greatest involvement in maintaining an upright posture, and it is also involved in extending the lumbar spine and moving it sideways. The quadratus lumborum muscle originates at the iliolumbar ligament and iliac crest, and extends into the transverse processes.

Thanks to the ultrasound scan, we can visualise the quadratus lumborum below the lower edge of the 12th rib, between the transverse processes from L1 to L4. The shadow of the lower pole of the kidney appears with respiratory movements and, above the kidney, the muscle mass of the quadratus lumborum (Fig. 3), then we see the insertion of the muscle into the iliac crest, where we will proceed to perform the block.

PIRIFORMIS

This muscle can produce referred pain in the lumbar area and at the back of the thigh. It is a small muscle located deep within the hip and buttock area. It inserts into the sacrum (the lowest part of the spine) and the femur (thigh bone). Its primary function is external rotation of the hip.

Myofascial pain syndrome of the pyramidal or piriformis muscle is usually the result of a contracture or spasm, which irritates the sciatic nerve below.

When contracture occurs in this muscle, it causes pain in the buttock area and can even lead to referred pain in the rear and lower part of the thigh. Patients often refer to deep pain from the hip to the buttocks.

Locating the piriformis muscle using ultrasound is not complicated. We locate the head of the femur and imagine a triangle between the gluteus maximus above, the iliac bone below and the head of the femur at the outer part, where the piriformis muscle is located (Fig. 4-5).

dolor miofaascial. Localización del músculo piriforme mediante ecografía

Fig. 4: Locating the piriformis muscle by ultrasound

Fig. 5: The arrow in the image above is pointing to the needle

PSOAS

This is a muscle that has little involvement in lumbar mobility and its main function is to move the hip. However, it originates at the side of the vertebrae and lumbar discs, so it can cause lower back pain if it suffers contracture. It is a deep muscle, so only accessible by palpating the insertion area and where it passes through the abdomen. Active trigger points can be found in these places.

Visualising the psoas muscle using ultrasound is not easy due to its deep location and the fact that it is obscured by bony structures, such as the transverse processes of the lumbar vertebrae, and the vertebral bodies that cast a shadow over the area of the muscle. By placing the ultrasound probe parallel to the axis of the spine in the lumbar region we find the psoas, and the area where we can block it, between the transverse processes.

ULTRASOUND-GUIDED TREATMENT OF MYOFASCIAL PAIN IN THE SPINE

At the Spine Unit, the patient and their family benefit from the experience of a strong team of specialists

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MYOFASCIAL PAIN IN THE SPINE

ULTRASOUND-GUIDED TREATMENT OF MYOFASCIAL PAIN IN THE SPINE

ULTRASOUND-GUIDED BLOCKS IN MYOFASCIAL PAIN

MYOFASCIAL BLOCKS

ULTRASOUND-GUIDED TREATMENT OF MYOFASCIAL PAIN IN THE SPINE

At the Spine Unit, the patient and their family benefit from the experience of a strong team of specialists

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