- Discussion:
- when the innervated ligamentous layer of the outer annulus fibrosis is stretched because of segmental instability, pain results;
- acute sprain probably represents partial tearing of annular tissue;
- if annular tissue becomes weakened to the point of allowing nucleus to protrude beyond the normal confines of the annulus, it may actually
be a prelude to subsequent episodes of frank disc herniation;
- if rent develops in annulus becomes complete tear to point of allowing nuclear liquid to escape, it may lead to a frank annular tear;
- instability or chronic ligament stretch produces discomfort ranging from mild and intermittent to persistent and disabling;
- mild discomfort compels us all to reduce lumbar lordosis inorder to ease the discomfort;
- more persistent variety can be recognized by strengthening spine flexors and correcting lordotic postures;
- pain from ligament stretch is midline & worse w/ lordotic postures;
- like most other mechanical back pain it is worse w/ bending & lifting;
- on PE, these pts also lack features identifying other pain syndromes;
- any diagnositic features to be found are in positive instability sign or a positive wt relief flexion test;
- Instability:
- instability test is performed with the patient prone w/ arms at sides;
- examiners thumbs finds interspace and exerts sharp downward pressure seeking a reproduction of pain;
- several interspaces are tested to find levels that are not painful for comparison;
- if no interspace is found or if all are painful, the test cannot be performed;
- if one or two levels are painful, the patient is asked to lift his head, shoulders, and arms and the downward pressure is repeated;
- if pain is greater when pt is prone & relaxed than when extended with paravertebral muscles tight, the test is positive;
- test stresses painful annulus in relaxed position, but contracted muscles stabilize segment, reducing stress & pain from pressure;
- if pain is greater w/ muscles contracted or pain is equal with both maneuvers, the test is negative;
- wt relief flexion is performed w/ pt supine, hips & knees flexed;
- examiner places one arm under pts knees and lifts pt's buttocks up from the examination table;
- if the pain is decreased with this maneuver, the test is positive;
- x-rays may show a narrowed disc space or a spondylolysis or spondylo-lithesis corresponding with the painful interspace - or interspace may be normal;
- Treatment Considerations:
- initial treatment is conservtive (as in most forms of low back pain);
- in the study by Suseki K, et al (1998), the authors used a rat model to demonstrate that sensory information from the
lumbar disc is conducted through rami communicantes;
- the authors point out that if the same non segmental pattern is found in man, then simple decompression of the nerve root would not
be expected to relieve discogenic pain