Lumbar Instability

Definition
  1. Lumbar Instability is typically defined as the loss of structural integrity between two adjacent vertebrae resulting in increased motion (hypermobility) at those segments.
  2. This increase in motion is usually greater than the normal anatomical limit of those segments.
Aetiology
Differential Diagnosis

History, Signs & Symptoms

History

  1. Commonly a history of lower back pain, which may or may not be accompanied by sciatica (with or without neurological signs).
  2. Lumbar pain is often relived by rest or by waring a support, but may recur with a small amount of movement, such as a twist or sprain.
  3. Pain made worse by maintaining one posture for a long period of time (standing or sitting).
  4. Pain is usually relieved by mobilisation or manipulation, often with complete resolution of leg pain and neurological symptoms. However, relief is temporary, giving way to recurring pain a few days later with no obvious triggers.
  5. In some patients, a steadily increasing lumbosacral ache when extremes of spinal movement are sustained for more then 15 seconds
  6. Some patients may also report a painful arc with lumbar flexion or coming out of flexion.
  7. In some cases, lumbar instability may cause a ‘catch’ in the back or even a ‘locking’ sensation.

Physical Exam

    • Range of Movement: Patients may have trouble bending forward because of pain; flexion or returning from flexion may show visible asymmetry with a painful catch.
    • Palpation:
      • General muscle hypertonicity to help stabilise unstable lumbar joints, multiple myofascial trigger points (MFTPs)
      • Lumbar joint may be palpate for hypermobile or even “clunk” during Stork test or extension from a prone postion
    • Orthopaedic Exam:
      • Nerve tension tests may be positive in late stages
      • Neurological deficits are usually absent, but may be present in the late stages
      • Patient may experience pain in the first part of a sit-up arc, but no pain in the last part of the arc (Farfan compression test)
      • In acute instability, patient may be unable to perform active bilateral leg raise

Imaging (x-ray)

    • In most cases x-ray imaging may show degenerative changes to the lumbar spine. However, only in severe lumbar instability would an x-ray demonstrate anterior shifting in affected vertebrae.

Management

Physical Treatment
  1. In minor lumbar instability, osseous manipulation with focus on the hypomobile segments will help reduce symptoms.
  2. Rehabilitation exercises to stabilise hypermobile segments are an essential part of treatment
  3. Standard manual therapy protocol
    • Ice and rest
    • Massage therapy, hydrotherapy
    • Conditioning & proprioceptive retraining
    • Electrotherapy: TENS, IFC, Ultrasound
    • Patient education – positions & activities to avoid
Severe Lumbar Instability
  1. With more severe grades of instability alternate treatment & caution should be employed
    • Consider bracing to help stabilize lumbar spine
    • Consider surgical consultation in severe cases or in the presence of neurocompressive radiculopathy
  2. Surgical treatment is usually spinal fusion