Thoracolumbar Junction Syndrome

Thoracolumbar Junction Syndrome is also called Maigne Syndrome or Dorsal Ramus Syndrome or posterior ramus syndrome. It is caused by the unexplained activation of the primary division of a posterior ramus of a spinal nerve.

In absence of any radiological signs, the diagnosis is made clinically.

The thoracolumbar junction (TLJ) is comprised of the T10-11, T11-12 and T12-L1 motion segments. This transitional area, interposed between the thoracic and lumbar spine, is often the source of a characteristic pain syndrome characterized by a referral of the pain in the related dermatomes (T10 to L1).

Anatomy of Posterior Rami

The thoracolumbar primary rami divide after a few millimeters into medial and lateral branches.

The medial branch runs dorsally along the angle between the transverse and zygapophyseal processes of the corresponding vertebra and gives off branches supplying the facet at that level.

A second inconsistent branch runs caudally to supply the facet at the level below. The medial branch then passes along the spinous process, supplying the periosteum of both the lamina and the spinous process prior to terminating at the tip of the latter.

It also innervates the multifidus muscle, one or two levels distal to their vertebral exit.

The lateral branch is directed caudally, laterally and dorsally, supplying the erector spinae and passing through the thoracolumbar fascia two to four levels caudal to their exit where it becomes superficial. This branch gives cutaneous innervation to the subcutaneous tissues of the lumbar and buttock area as distal as the greater trochanter.

Causes of Thoracolumbar Junction Syndrome

The most common cause of the Thoracolumbar junction syndrome is a minor intervertebral dysfunction at the thoracolumbar junction.

The nature of this dysfunction remains unknown, although the involvement of either the facets or the disc is very likely. More than any other part of the spine, the Thoracolumbar junction syndrome is involved in rotatory movements.

This may lead to an overuse of the motion segment which could initiate disc or facet degeneration. Disc herniation or a collapse of the vertebral body of T11, 12 or L1 may also be responsible.

Other causes are entrapment of cutaneous dorsal ramus of L1 when it crosses the iliac crest and becomes superficial by perforating a rigid fibro-osseous tunnel formed by the thoracolumbar fascia above and the rim of the crest below.

Similarly, entrapment of the lateral cutaneous branch of the iliohypogastric nerve may cause the pain.

Clinical Presentation

Depending on the branch involved, the pain could refer to

Low back (cutaneous dorsal rami)
The groin (subcostal or iliohypogastric nerve)
Lateral aspect of the hip (lateral cutaneous rami of the subcostal or iliohypogastric nerve)

All combinations of these clinical presentations are possible.

Low Back Pain is certainly the most frequently encountered pain complaint. The pain is usually spread in the lateral part of the low back without corresponding exactly to a specific dermatome.

Rarely, the pain is bilateral.

The pain is usually acute, of less than 2 or 3 months duration, often appearing after a rotatory movement of the trunk, prolonged strenuous posture, lifting and occasionally, without any obvious precipitating factors.

Less commonly, the pain may have a more chronic course.

The pain is frequently increased by contralateral side bending.

On examination, there is pain and tenderness in iliac crest at a point which is consistently located seven centimeters from the midline. The pressure at this point causes a sharp excruciating pain similar to the patient’s complaint.

The opposite iliac crest is commonly unaffected.

The pinch-roll test is usually positive. It can be revealed by gently grasping a fold of skin between the thumbs and forefingers, lifting it away from the trunk and rolling the subcutaneous surfaces against one another in a pinch and roll fashion. On the involved side, the skin overlying the buttock and iliac crest is found to be tender when compared to the opposite side.

Hyperalgesia is responsible for this test.

Examination of thoracolumbar junction area may produce tenderness.

The affected posterior ramus ends cutaneously causing trophic changes of the skin referred to as cellulalgia consisting of thickening or nodularity of the skin and hair loss or swollen puffy appearance.