LUMBAR PAIN

 

Mauro Keiserman, MD. Rheumatology Specialist by the Brazilian Society of Rheumatology. Head Professor of Rheumatology at the Catholic University School of Medicine (PUC-RS).

 

Synonyms:

Lumbago

Eighty per cent of the human beings feel lumbar pain (lumbago) at some point in their lives. A smaller number suffers from cervical pain (neck) and pain in the back of the neck, while others experience dorsal pain. The majority of these people can go about their habitual activities, but these will be accomplished at periods of discomfort or pain. Nearly 30% of this group won't be able to go to work due to lumbago.

What are the causes of lumbago?

In most cases, pain is related to mechanical problems in the spine, that is, malfunctioning. The main treatment consists of normalizing the function, which can be achieved with exercises and further postural care.

Other causes are also found frequently:
 

osteoarthritis (arthrosis) of the intervertebral joints and
intervertebral disk degeneration (degenerative discopathy)

Less frequent causes:
 

spondylolisthesis
uni or bilateral sacralization of the transverse apophysis of the 5th vertebra
piriform muscle syndrome and
sacroiliac joint diseases.

This chapter is dedicated to posture, since prevention or correction of bad posture avoid, improve or correct most problems that lead to lumbago.

What's posture?

Posture is the body's position.

A good posture can be defined as a harmonic arrangement of the constituting parts of the body, both at stationary position (standing still) and in different dynamic situations (motion and strength).

When we talk of the spine, posture is the erect and stationary spinal column (standing up).

The erect position is achieved through the soft tissues of the spine: muscles, ligaments and articular capsules.

A good posture results from the ability of the ligaments, capsules and muscle tonicity to support the erect body, allowing it to remain at the same position for long periods without discomfort. An acceptable posture must also be esthetically appreciable.

Therefore, when somebody gets tired of standing in a movie theater line, feels discomfort or pain, if they spend too much time watching TV, or need to go to bed early on Sunday because of backache, symptoms of spinal posture disorder are present.

Thus, posture examination is the evaluation of the spinal position, the inter-relationship of its curvatures and the elements involved in its harmony or unbalance.

Posture exam is part of the physical evaluation of the locomotive apparatus and must be supplemented by a kinetic study (motions) of the spine for a suitable functional interpretation of the complaints or findings that might be ascertained.

What's the spinal column? How does it work?

The spinal column is an ensemble of overlapped vertebrae and discs.

Two vertebrae separated by an intervertebral disc form a unit.

The anterior segment of the functional unit is prepared to support weight, absorb shocks and have flexibility. In the posterior segment are the nerve structures (marrow and nerve roots) and a pair of joints that orient the motions of every unit. The ligaments, whose function is to support, and the muscles are the other constituting elements of the spine.

The static spine

Viewed from the side, the spine has four physiological curvutures: the cervical and lumbar lordosis and the dorsal and sacral kyphosis. It is supported by the sacrum, which lies between the iliac bones. The last lumbar vertebra and the first sacral vertebra take on a physiological angle that orients the position of the spinal column. The lumbosacral angle is determined by drawing a line parallel to the upper surface of the sacrum oriented to a horizontal line, and measures roughly 30 degrees. It depends on the position of the pelvis, which, by its turn, is centrally balanced in a transverse axis located between the coxofemoral joints (thighs with the pelvis). Any rotational motion of the pelvis modifies the lumbosacral angle. The anterior inclination (raising of the anterior region of the pelvis) decreases this angle, while the inverse motion, posterior inclination, places the sacrum at a horizontal direction, accentuating the lumbosacral angle and the lumbar lordosis.

The position of the pelvis is maintained by means of the ligamentary control of the coxofemoral joints. While standing on the two feet, the stretch of the coxofemoral joints is restricted to a neutral position by the iliopectineal ligaments, which consist of the thickening of the anterior capsular tissues of the coxofemoral joints. The pelvis is also supported by the tensor of the fascia lata, which reinforces the position of the hips and avoids the hyperextension of the knees; this fascia has its proximal attachment at the iliac crest and distal attachment at the iliotibial tract on the lateral surface of the knee. The support of the lower limbs is achieved, in the knees, by means of the posterior articular capsule and the ligaments, the contraction of the quadriceps being unnecessary. There's a little muscular contraction in the calf, with minimal expense of energy. Therefore, we can observe that the maintenance of an upright posture is basically associated to the ligaments with minimum energy expense.

Viewed from the front, a normal spine must not have lateral deviations, or these must be minimal. This requires a suitably aligned sacrum, that is, a horizontalized sacrum. What determines the horizontalization of the sacrum is an equality in the length of the lower limbs. Asymmetric pelvic development is also a cause to sacral deviation, albeit rare. In either situation, there will be a decrease in pelvic height on the affected side, and the sacrum will be bent, and, consequently, there'll be a secondary scoliotic attitude (not real scoliosis) with asymmetry and overload on the joints between the vertebrae. Should the scoliosis not be corrected, structural changes will occur to the articular facets and intervetebral discs due to the asymmetric overload.

Functional unbalance of the spine

The equilibrium of the spine must be maintained against the gravity, using minimal energy and causing an energy waste as low as possible. In order to minimize energy consumption, the muscles don't participate in this function significantly, the main supportive activity falls to ligaments and capsules. When the tension on ligaments excels the physiological limits there's a reflex isometric muscle contraction (the muscles are contracted without moving), protecting them from further stretch.

Supported muscle contraction leads to fatigue and consequent inability to protect from excessive stretch. In the first phase of postural overload, patients report discomfort and fatigue, pain in the soft tissues being a later event.

Many are the factors involved in what can be called spinal posture disorder.

However, four factors prevail as regards influence and frequency:
 

Lumbar hyperlordosis (lordosis is a concave position; hyperlordosis is an excessive concavity).
Esthetically normal posture, but unprepared musculature and/or insufficient flexibility of soft tissues.
Congenital or acquired structural anomalies (neurological, muscular, skeletal, ligamental).
Postures acquired by bad habit or unsuitable training over the developmental years.

Lumbar hyperlordosis

Most people suffering from static posture lumbago have hyperlordosis.

Examples of transient hyperlordotic postures that may provoke pain:
 

pregnancy,
sleeping with the belly downwards on a soft mattress,
wearing high heels (they push the body forward and force a hyperlordotic attitude to rebalance it),
 

In these situations, should the excessive lordosis be undone, pain is either relieved or vanishes away.

The mechanisms likely to lead these patients to experience pain could be understood as follows:
 

The articular facets get close, and excess compression leads to pain;
The intervertebral orifices have their diameter decreased, and the sensory nerve roots that head to the muscles, joints and ligaments are compressed;
The disc protrudes posteriorly, pressing the posterior longitudinal ligament and irritating nerve endings.

The stimuli transmitted by the sensory fibers start a reflex reaction that leads to excess muscle contraction, which aims at protecting the compromised functional unit. However, the supported muscle contraction becomes a new pain spot, and further aggravating the condition, the intense contraction also compresses the injured tissues, completing an endless cycle of pain-contraction-pain.

This conceptual model of lumbar pain related to hyperlordosis has been accepted for over 100 years.

However, occasionally, the pathogenesis of lumbago is the permanence in lumbar flexion for a long period, as happens to modern man, who remains most of the time sitting. In this position, the posterior tissues are stretched out excessively and allow the intervertebral disc to be pushed backwards.

Treatment in these cases consists of promoting exercises to strengthen the extensor muscles, restoring anatomical lordosis.

It's the physician's duty to determine if the patient's symptoms are due to hyperextension or hyperflexion. Causing pain on recreating the abnormal position sheds light on the physiopathogeny of each particular situation.

Postural disorder related to weak muscles and/or musculo-ligamentary rigidity

A quite common condition that causes lumbago is a normal spine with weak abdominal muscles. The abdominal muscles have to be powerful in order to support the pressure exerted by the abdominal cavity and, also, to balance the forces of the spine's erector muscles; otherwise, there'll be an increasing trend to accentuating lumbar lordosis.

Another frequent and important condition (and many times unidentified) related to lumbago is the lack of flexibility in the muscles and posterior ligaments of the loins, thighs and legs.

The spine can be flexed 45 degrees. For an adequate flexion, the erector muscles, their fasciae and the longitudinal ligaments must be enough extendable.

After the 45 degrees of spinal flexion, the trunk completes the movement by flexing the pelvis. The anterior rotation of the pelvis is carried out around the coxofemoral joints and is restricted by the length and stretch degree of the posterior muscles in the thighs and legs

If the tissues lack enough flexibility, the attempt at reaching a maximum range will cause pain due to excessive stretch, and, eventually, structural damage.

Congenital or acquired structural anomalies

On evaluating the erect spine, we must seek defects in the lower limbs or in the spine proper. There's a plenty of causes to length asymmetry in the lower limbs.

A difference up to 1 cm is deemed normal and must be taken into account only if no other cause to pain and discomfort of postural origin is found.

Causes to lower limb shortening:
 

Congenital hypoplasia
poliomyelitis
Post-fracture
Genu valgum or knock-knee
Asymmetric genu recurvatum
Asymmetric calf contraction with the foot in equinous position
Dispraise de quadrilles
Coxarthrosis

Postures acquired by bad habit or during the developmental years

The influence from cultural, social and professional patterns, habits, training and psyche over posture are important and numerous, their identification being many times hard to do. The association of factors, including the structural ones, further aggravates the problem.

We must also mention the gestures done at work while both standing up and sitting, the different models of seat that cause overload and excess stretch, and the different ways of sitting down, including on the floor, influenced by cultural (and also religious) reasons.

The psyche importantly contributes to posture. Posture is the body's language.

Partly, we move and stand still according to what we feel.

Depressed individuals keep a downcast attitude, with the trunk bending downwards and the shoulders projected forward, resembling a very tired person. This attitude leads to an abnormal stretch of ligaments and to pain, becoming fatiguing, as keeping this position causes overload on the extensor muscles, adding physiological tiredness to the preexisting psychological feeling.

Pain is a psychological sensation. It's felt by someone that will later describe it, expressing their reaction to pain and interpretation of the meaning of their suffering. An experienced observer must know how to distinguish between what we call physical pain and the enhanced pain observed in emotionally ill patients.

Hyperkinetic individuals, due to aggressiveness, and anxious ones, who persistently remain tense, express their feelings through posture as well.

Their position is one of unbalance, the body staying before the center of gravity, and all muscles in a constant state of supported contraction.

It's common to find teenage girls of tall stature that try decreasing their height by bending their back (teenager's curved back). Teenagers with large breasts or short stature can also modify their posture.

The practice of sports over the developmental years may lead to body asymmetry, as happens to basket and tennis players.

Also among children and teenagers psychic disorders importantly contribute to unsuitable postural attitudes.

All postural patterns acquired during the growth period can linger on and become problems in adulthood. Tissues develop according to the stimuli taking place, and the completion of their development may eventually be defective.

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