⁽¹⁾ The patients virtually never complain of pain at the level of the TLJ. Pain caused by a disorder at this site is invariably referred to a different site.

⁽²⁾ Only rarely will there be radiographically demonstrable degenerative disease at the level of the TLJ (T11 - T12 - L1).

⁽³⁾ The diagnosis can be made only in the light of a detailed and systematic clinical examination, which will show a tender spinal segment at this level.

The usual cause is what I have termed painful minor intervertebral dysfunction (PMID), most commonly at T12/L1. In some very rare cases, the problem may be due to a prolapsed intervertebral disk.

The most frequent manifestation of this thoracolumbar junction syndrome is low back pain, which is exactly like low back pain of lumbosacral or sacroiliac origin. This pain was the first feature to which our attention was drawn ⁽¹⁹⁷²⁾. However, there may also be lower abdominal pain mimicking visceral problems, or pain mimicking trochanter bursitis; in an even smaller number of cases, there may be pubic pain.

These symptoms may occur by themselves, or in association.

The pain pattern coincides with the distribution of the corresponding spinal nerves (T12, L1). It is due to reflex tissue disturbances as a result of a celluloperiosteomyalgic syndrome of spinal origin (R. Maigne), shown by the clinical examination of the patient (Fig. 1).

Figure 1: A) Distribution of the spinal nerves T12 and L1 1. Anterior ramus 2. Posterior ramus 3. Perforating lateral cutaneous branch B) Referred pain from the TLJ is felt in the cutaneous distribution of these nerves; the skin and subcutaneous tissues are the site of reflex cellulalgia. However, the pain is felt as deep pain. 1. Low back pain (posterior ramus) 2. Pseudovisceral pain and groin pain (anterior ramus) 3. Pseudotrochanteric pain (lateral perforating branch) Usually, the cause is painful minor intervertebral dysfunction of a TLJ segment.

The syndrome is diagnosed exclusively on clinical criteria.

This difference is mainly due to the way the facet joints are oriented. In the thoracic spine, the orientation is essentially in the coronal plane; while in the lumbar spine, the facet joint surfaces are sagitally aligned. As a result, the thoracic spine should be particularly mobile, especially in rotation, were it not for the tethering effect of the ribs. On the other hand, there is virtually no rotation in the lumbar spine, except in slight flexion. In extension, rotation of the lumbar spine is completely impossible.

Anatomically and physiologically, T12 is a transitional vertebra, both in man and in most quadrupeds. In some subjects, the transitional vertebra may be T11. The vertebra concerned marks the boundary between the cervicothoracic part and the lumbosacral part of the spine.

The superior facet joints of T12 are shaped like those of the thoracic vertebrae, while the inferior ones have the pattern of lumbar facet joints. This means that the harmonious movement of the spine is broken at this site, and explains why this part of the spine is particularly susceptible to stress. T12 is, as it were, a hinge around which the two parts of the spine change position as the vertebral column is flexed laterally or forwards, or extended (Fig. 2).

Figure 2: Facet joint orientation in the T-spine and the L-spine. Facet joints are - in the coronal plane in the T-spine, permitting rotation; - in the sagittal plane in the L-spine, making rotation impossible. T12 is a transitional vertebra, with thoracic-type superior, and lumbar-type inferior, facet joints. Cervical vertebra Thoracic vertebra Lumbar vertebra

It is well known that the 11th and 12th thoracic vertebrae, and the first lumbar vertebra, are particularly frequently the sites of crush fractures as a result of trauma. It is also remarkable that this highly-stressed junction between the thoracic and the lumbar spine is not very much affected by degenerative disease - quite unlike the lumbosacral junction, where degenerative lesions are much more common.

We have not found a higher incidence of these degenerative lesions in patients with TLJ syndrome, as compared with age-matched controls.

It would, however, appear that patients with marked sequelae of Scheuermann's disease, or Schmorl's nodes, at the thoracolumbar junction, are much more prone to TLJ syndrome.

Figure 3: Skin territories innervated by T12 and L1 These two nerves have a similar distribution: 1 - Territory of the posterior ramus 2 - Territory of the anterior ramus 3 - Territory of the lateral cutaneous branch of the anterior ramus

• The anterior rami supply
• the skin of the lower abdomen, the medial aspect of the upper thigh, and the labia majora or the scrotum;
• the lower part of the rectus abdominis and transversus abdominis muscles;
• the pubis.

Each of the anterior rami of T12 and L1 gives a lateral cutaneous perforating branch, which emerges above the greater trochanter and supplies the skin of the upper lateral part of the thigh.

The cutaneous branches of the posterior ramus supply the skin of the lower lumbar and the upper gluteal region; branches from T11 and L2 contribute to this innervation.

There are many anastomoses, and many anatomical variants.

Since our first description of the syndrome ⁽¹⁹⁷²⁾, we have performed several anatomical studies of the skin innervation pattern in this area. The latest series of dissections was performed by J.Y. Maigne ⁽¹⁹⁸⁸⁾. He found three different patterns of the cutaneous branches of the posterior rami mentioned above (Fig. 4).

Figure 4: Cutaneous branches of the posterior rami supplying the gluteal region. The most medial of the posterior rami always crosses the iliac crest at a distance of 7 or 8 cm from the line of the spinous processes. Note that the T11 posterior ramus supplies a skin zone that straddles the iliac crest, while that of L3 (if present) unites with the posterior ramus of L2. Between the rami, there are anastomoses near their origins at the vertebrae.

- In 60% of the cases, L1 crosses the iliac crest at a distance of 7 cm from the midline; while the crossing point of T12 is a little more lateral.

- In 40% of the cases, L2 crosses the iliac crest 7 cm from the midline; while the crossing point of L1 is a little more lateral.

- It was also found that the most medial branch passes through an osteofibrous tunnel, in which it is rather crowded and may be severely compressed (2/37 dissections).

For the examination, the patient is positioned prone across the couch, with a cushion under the abdomen. The examination must be performed with meticulous attention to detail.

1. Lateral pressure on the spinous processes
The search is conducted from T9 to L3, exerting pressure on each spinous process, slowly but firmly, and tangentially to the skin. The test should be done with one thumb or - preferably - with one thumb on top of the other. The test is performed from left to right, and then repeated from right to left. In the case of PMID, pain will usually be felt in one direction only - in right-sided low back pain, right-to-left compression will provoke pain; left-to-right tenderness is rarely seen (Fig. 5).

2. Compression-friction of the facet joints
The tip of the middle finger (preferably with the index finger placed on top of the middle finger for bracing) is used to exert firm, slow pressure and friction along a line paralleling the spinous processes, at a distance of 1 cm from the midline, on either side. This manoeuvre must be performed with firm and constant pressure, and up-and-down movements along the spine. At the healthy levels, it will be painless; at the affected level, however, it will provoke pain at the level of the involved facet joint either on the right or on the left, depending on the affected side (Fig. 6).

Figure 5: Identification of the TL level that is causing the symptoms: Slowly applied lateral pressure on the spinous processes, from T10 to L2, first on the right, then on the left. This manoeuvre will provoke pain in the segment concerned, usually in one direction only (right-to-left, or left-to-right). Note patient positioning for the examination.

Figure 6: Identification of the facet joint point. The examiner's finger is run along the patient's back at a distance of 1 cm from the midline, exerting pressure on the paravertebral region from T10 above to L2 below, firmly rubbing with reciprocating movements of the finger tip. This will show tenderness at the facet joint concerned; this tenderness will always be on the same side as the "crest point." The local anaesthetic or corticosteroid should be injected into this facet joint point.

- Two other signs may be found in the same segment, although they are less consistently encountered: Tenderness of the spinous process on p.a. compression exerted with one thumb placed on top of the other; and tenderness of the interspinous ligament of the segment concerned, elicited by pressure with the bow end of a key.

This segmental examination will show one segment, or occasionally two adjacent segments, of the TLJ to be tender (Fig. 7).

Figure 7: Most commonly, the T12/L1 segment will be tender on examination; however, this sign may also be found at T11/T12 or L1/L2. Segmental examination manoeuvres

The manifestations concerned are reflex neurotrophic phenomena caused by the painful dysfunction of the vertebral segment, in the distribution of the corresponding spinal nerve. They are found in the skin and subcutaneous tissues (cellulalgia), in some of the muscles (myalgic cords); and in the tendinous insertions, which are very tender on palpation. As a rule, the patient does not complain of pain in these structures.

- "Cellulalgia": The skin fold is thickened to a greater or lesser extent, and pinching-and-rolling will always elicit tenderness; these signs are found in all or part of the cutaneous territory supplied by the spinal nerve concerned.

- "Myalgic cords": Palpation will show hardened and tender bands in some of the muscles supplied by the same nerve.
These cords may have trigger points giving rise to pain at distant sites. Finger pressure on these points will elicit this referred pain.

- Excessive tenderness of the tendinous insertions.

In TLJ syndrome, the chief feature is cellulalgia. It is found, unilaterally, in any one or in all of the three cutaneous territories supplied by the spinal nerve concerned: posterior territory (posterior ramus); anterior territory (anterior ramus); lateral territory (lateral cutaneous branch). Also, myalgic cords will be found in the quadratus lumborum muscle, and in the lower part of the rectus abdominis; and the muscle insertions on the pubis may be tender.

All these reflex manifestations are found on one side - the side with the facet joint tenderness in the vertebral segment affected by PMID.

Some of the features described above may be missing.

Posterior cellulalgia is the most frequently found, and virtually consistent, feature.

The reflex manifestations described are not always "active," i.e. responsible for the patient's symptoms. Some are "inactive", and discovered only on examination. They may, however, become "active" at any time.

Thus, patients who complain only of low back pain may be found to have not only "active" gluteal region cellulalgia, but also a zone of cellulalgia over the abdomen, with severe pain provoked by pinch-and-roll, but no spontaneous pain in this region.

There is, thus, not just one TLJ syndrome, but two syndromes:

- a TLJ sign complex found on systematic examination; this syndrome is often complete; and

- a TLJ symptom complex reported by the patient; this syndrome affects only one or two of the regions; involvement of all three regions is rare.

It is important to note that the signs may be elicited even at times when the patient is symptom-free.

Low back pain is the most frequent complaint. It may be associated with one or more of the following symptoms: abdominal pain mimicking visceral disease (pseudovisceral pain); hip pain; or pubic pain. It may be overshadowed by one or other of these symptoms.

Low back pain of thoracolumbar origin

This was the first manifestation of TLJ syndrome identified by us ⁽¹⁹⁷²⁾; we described its characteristic features under the name of high-origin low back pain. In the majority of cases, this is chronic pain; however, there may be acute patterns.

• The pain, which is generally unilateral, is always felt in the sacroiliac or low lumbar region; sometimes, it may radiate posteriorly, or laterally into the thigh. It is exactly like low back pain of lumbosacral or sacroiliac origin, and is, in fact, invariably, mistaken for that kind of pain.

   

• The patient never complains of anything wrong with his or her thoracolumbar junction.

In the chronic form, which is the most commonly encountered pattern, the pain is mechanical, i.e. it is made worse by exertion and by certain positions. It is always felt as a deep, not as a superficial, pain. It is more common in the over-50s than in younger subjects; however, it may occur at any age. It may be isolated, or associated with low back pain of lumbosacral origin.

In the acute form, the pattern is that of acute low back pain after exertion or a false movement (usually a rotational movement). The spine will be found to be stiff and painful, very immobile, but usually without the antalgic position commonly found in low back pain originating at L4/L5 or L5/S1. The condition is most frequently seen in subjects over 50 years of age.

1. Signs
As pointed out above, the examination of the TLJ, segment by segment, will show a PMID, most often of T12/L1. Sometimes, T11/T12 or L1/L2 will be found to be affected; in some cases, the dysfunction will be at T10/T11, if T11 the transitional vertebra.

The signs described below are usually found on the side of the painful facet joint affected by PMID. This means that they are unilateral, even if the patient may, occasionally, have the impression that the pain is in the midline or bilateral.

a. The posterior iliac crest point
The examiner's index finger is run along the iliac crest from medial to lateral, rubbing the crest with little to-and-fro and up-and-down movements (Fig. 8 a and b).

Figure 8: a) Identification of the crest point. The examiner's index finger is rung along the patient's iliac crest, with up-and-down and to-and-fro rubbing movements. Compression against the bone of the irritated nerve will provoke sharp pain at a well-defined site; this pain will often be described by the patient as being identical to his or her usual complaint. b) Most commonly, the crest point is 7-8 cm from the midline; it may be more lateral, and sometimes will be found to be slightly more medial.

At a well-defined point - usually 7 or 8 cm from the midline - this manoeuvre will provoke sharp pain, which the patient will frequently report to be identical to the spontaneous pain felt by him or her. It is at this point that the irritated cutaneous branch from T11, T12, and L1 is compressed. It is called the posterior iliac crest point. Tenderness at this site is often, mistakenly, ascribed to iliolumbar ligament tenderness. However, that ligament is on the inside of the ilium, and, therefore, inaccessible to palpation.

There is one interesting observation: Even though, in some cases, the crest point may be more laterally situated, the usual distance from the midline is 7-8 cm, regardless of level (T11/T12; T12/L1; L1/L2). Following the infiltration with local anaesthetic of the facet joint at the affected level, the crest point will no longer be tender.

As discussed above, the crest point corresponds to the site at which the most medial cutaneous branch (usually L1, but sometimes L2) crosses over the iliac crest.

The findings are accounted for by the following facts:

⁽¹⁾ The facet joints are innervated by several levels. Most authors describe a supply from three levels; while Wyke has postulated a five-level supply.

⁽²⁾ The most medial branch is the only one to course in an osteofibrous tunnel, in which it may suffer further irritation and even compression.

This results in what the Americans have called a "double-crush syndrome", which may give rise to symptoms.

We have, however, found that surgery is only very rarely required in such cases.

b. Gluteal cellulalgia - The pinch-and-roll test
The skin and subcutaneous tissues of the lower lumbar and upper gluteal region are examined with the pinch-and-roll test. This manoeuvre consists in picking up a skin fold by pinching it firmly between the thumb and index finger, and rolling the fold like a cigarette, without releasing the pinch.

In a healthy zone, this manoeuvre should cause no or only very slight pain. However, in a cellulalgic zone, it will be very painful. Also, in this limited zone, the skin fold is often thickened, and may, at times, be greatly increased in thickness.

This test should be applied in a carefully controlled way, and as appropriate to the individual patient; above all, however, it must involve a comparison with the opposite side and with the surrounding areas.

The zone involved will vary in size; it may extend to almost the entire upper gluteal region, or cover only part of that region, adjoining the crest point (Figs. 9, 10, 11).

Figure 9: Pinch-and-roll. This manoeuvre shows a zone of greater or lesser extent, adjacent to the crest point, where the skin fold is thickened, oedematous, and painful when pinched and rolled (while in the neighbouring zones and on the other side of the spine, pinching-and-rolling would not be painful). The skin is grasped between the examiner's thumb and index finger and pulled up in a fold; while upward traction is maintained, the skin fold is rolled backwards and forwards.

Figure 10: Cellulalgic zone and crest point. The size of the zone will vary in different patients.	Figure 11: Note the difference between the level of origin (never spontaneously painful) and the region where the pain is felt.

2. Demonstration of thoracolumbar origin of the low back pain
Proof of the thoracolumbar origin of the pain is afforded by the pain relief obtained when the facet joint point that was tender on examination is infiltrated with a local anaesthetic. The needle is inserted at right angles to the skin, at a distance of about 1 cm from the midline, in contact with bone. The plunger is pulled back to check that the tip is in the correct place, following which 2-3 mL of lignocaine is injected. This will produce almost instantaneously

1. relief of pain and discomfort: the patient can freely bend forwards, turn around, straighten his or her back.

2. disappearance of the tender crest point;

3. reduction in, or even complete disappearance of, the "cellulalgic zone," with the skin becoming supple and non-tender when subjected to pinch-and-roll.

This infiltration involves the posterior branch as well as the facet joint. We would advise that the needle be left in situ, and that the examiner wait fifteen seconds to see whether the skin is no longer painful when pinched and rolled, and whether the crest point has become non-tender on palpation (Figs. 12 and 13). If no change can be observed, this should be taken as evidence that the needle is at the wrong level and will need changing slightly. Manipulation will produce the same result: If the manipulative manoeuvre is performed at the correct level, the thoracolumbar facet joint will cease to be tender.

 

Figure 12: Infiltration is performed with the needle in contact with the tender facet joint. The injection may be made for testing purposes (lignocaine) or for treatment (corticosteroid).	Figure 13: TL facet joint infiltration with a local anaesthetic will, within a few seconds, relieve the crest point tenderness and the cellulalgia. The needle is left in situ while waiting for the result. Usually, the injection is made without fluoroscopic guidance. However, guidance should be employed if the clinical picture is typical and the injection does not provide relief.

 

Conversely, if a "placebo" saline injection is made, or if the lignocaine is injected at a different level or further away laterally from the facet joint, the patient will not experience pain relief; the tender crest point will persist; and the signs of cellulalgia will still be found when the pinch-and-roll test is performed.

3. Prevalence
This isolated form of low back pain accounts for ca. 30% of all cases of low back pain in our patient material. It is more common in patients over the age of 50. It may also occur in association with low back pain of lumbosacral origin - this is what we call a mixed form. In this condition, the relative contributions to the overall picture of the two pain sources will vary over time.

One pitfall in the diagnosis of this low back pain of thoracolumbar origin is the frequent occurrence of radiologically demonstrable low lumbar (L4-L5-S1) pathology such as HNP, facet joint degenerative disease, or spondylolisthesis, which attract the physician's attention but may not, in actual fact, have anything to do with the low back pain.

Low back pain which persists after successful disk surgery for sciatica is often thoracolumbar in origin (Fig. 14).

 

Figure 14: This patient had previously undergone surgery for sciatica, with excellent relief of the pain in his leg, but persistence of refractory low back pain, which was thoracolumbar in origin.