Definition PROLAPSE INTERVERTEBRAL DISC
It can be defined as protrusion of a portion of the nucleus pulposus of an intervertebral disc into the spinal canal. This condition is commonly occur at the lower two lumbar disks which are L4-L5 and L5-S1, and followed by the two lower cervical disks. Intervertebral disk functions to transfer the load from one vertebrae to the next, without collapsing them and accommodate the rocking movements of the vertebrae.
ANATOMY
It consists of two basic components: nucleus pulposus and annulus fibrosus.
Nucleus pulposus: consists of type II collagen that contain of proteoglycan. The hydroscopic properties of the proteoglycan matrix give the nucleus hydrostatic properties, allowing it to accommodate compression loads and to brace the annulus.
Annulus fibrosus: a ring of tough fibro-cartilage that control direct movement at vertebral level.
Pathophysiology
Prolonged mechanical loading of the spine can lead to microruptures in the annulus fibrosus, resulting in degeneration of the disk. The initial sign is the softening of the annulus.
There are also reduced proteoglycan content within the disc (and consequent decreased hydration and function) and decreased endplate permeability (and consequent decreased metabolic exchange). Simultaneously, the type II collagen molecules are replaced by the denser type I collagen molecules in the nucleus. These type I molecules tend to crosslink and form even denser tissue that further inhibits exchange of nutrients and metabolic waste.
As the degeneration progress, the portion of nucleus protrudes through a tear in the softened annulus at its weakest part, this being postero-lateral, and the extruded material may impinge on the adjacent nerve roots or the spinal cord itself. The protrusion may be episodic, may continue intermittently over a period of months or years and it accelerates the degeneration of the disc (Shankar et al, 2009).
Posterolateral PID: most frequent as a result of torsion and compression. It can compress the nerve root either a lateral or medial side.
Posterior PID: can deform the posterior longitudinal ligament and compress dural sac without irritating the nerve root (Maigne, 2006).
Mechanism of injury
Sudden strenuous activity (such as lifting a heavy weight or twisting violently). Over the age of 30, discs start to dehydrate and become less resilient, but after 40 extra fibrous tissue forms around them, increasing the stability. Hypertension and diabetes mellitus are also frequently cited as risk factors for PID.
Clinical pattern
- Men are commonly affected compared than female.
- In early stages: complaint of pain usually in lower back but sometimes in the posterior buttocks or thigh. Leg pain indicates larger protrusion than does back pain alone.
- Nature of pain: dull ache or knife-like pain
- Onset of pain: sudden and severe or may develop gradually
- Difficulty in sleeping as the pain becomes severe.
- Sometimes accompanied with numbness and muscle weakness.
AGGRAVATING FACTORS
- Straining, stooping, sneezing, coughing, car travel and sitting provoke pain
- Prolonged sitting cause the pain to move from lower back to the leg. Zeller, 2006
- Forward flexion of the spine will often reproduce the patient’s sciatic pain to a greater or lesser degree
- Repetitive motions or high number of motion cycles.
- Heavy lifting and straining may exacerbate the condition
EASING FACTOR
- Changing position
- Rest
- Taking painkillers
- Apply cold and heat
- Exercise
TREATMENT
Conservative-about 80% people will improve in 6 weeks of treatment. Bohinski, 2009
Aims in conservative treatment:
- To reduce irritation of the nerve and disc
- To improve physical condition of patient
- To give protection to spine & indirectly will improve spine function
Example of treatments:
- Education (emphasize on wearing lumbar corset and comfortable position)
- Rest
- NSAIDs
- Analgesic drugs
- Physical therapy
- Exercises
- Modifications of ADL so less stress is put on lower back
Operative: Goal-: to make the herniated disk stop pressing on and irritate the nerves that causing symptoms of pain and weakness.
Most common:
- Discectomy
- Partial discectomy
- Hemi laminotomy
- Hemi laminectomy
- Endoscopic
EXAMPLE OF PHYSIOTHERAPY INTERVENTION
1- Joint mobilization
Aim: to increase mobility of the spine.
Pt. position: prone ly.
Procedure: apply central glide at L1-L5
Dosage: 60 oscillates, 5s rest, 3sets
2- Stretching exercises
a) Hamstrings
Aim: to increase flexibility of muscles.
Pt. position: supine ly.
Procedure: using a towel placed on pt’s foot, pt hold each end of the towel and pull leg straightly, do for both legs
Dosage: hold 15s, 5reps
b) Piriformis
Aim: to increase flexibility of muscles
Pt. position: supine ly.
Procedure: flex Rt. knee, place ankle of the Lt. leg on top of Rt. Knee. Bring Rt. Knee to the chest. Do for both legs
Dosage: hold 15s, 5reps
(you can see more exercise of piriformis here)
3- Back exercises
a) Trunk rotation
Aim: to stretch & mobilise trunk.
Pt. position: crook supine ly.
Procedure: bring both knee down to the right & to the left
Dosage: hold 10-15s, 5reps
b) Mc kenzie exercise
Aim: to peripheralize the symptoms of pain
Pt position: prone ly.
Procedure: do trunk extension in prone ly.
Dosage: hold 10s, 5reps
4- Lumbar stabilization
a) Bridging
Aim: to strengthen back muscles
Pt. position: crook supine ly.
Procedure: slowly lift up buttock until hip straight.
Dosage: hold 10s, 5reps
b) Cat & camel exercises
Aim: to strengthen trunk stabilizers muscles
Pt position: kneel down on 4 limbs
Procedure: slowly allow trunk to sag as far as pt can so that the back form an arched, lift up face toward ceiling. Then, round back up at the waist as far as the pt can, lower the face toward the floor.
Dosage: hold 10s, 5reps.
5) Pain management
Aim: to reduce pain
Pt. position: prone ly.
Procedure: apply hot pack at lower back
Dosage: 20 minutes
6) Pt education
- Reduce weight as reducing weight can help reducing pain at lower back. Reduce load taken by the spine.
- Posture correction: - Practice a good posture while lifting heavy object, bend hip & knee, maintain straight back, place load near the COG and slowly lift the load.
- Do not twist the trunk while lifting heavy loads with foot planted on the ground as it will give more stressed on the spine. Twist the whole body.
7) Home Exercise Programme
- Do exercises as taught at home frequently
- If pain increased after doing all the exercises, stop the exercises immediately and seek medical attention.
REFERENCES
Bogduk, N. (2005). Clinical Anatomy of the Lumbar Spine and Sacrum. 4th ed. Elsevier Churchill Livingstone.
Bohinski,R.(2009). Herniated lumbar disc :Basic level. Mayfield Clinic.
Hadjipavlou, A. G. et al. (2008). The pathophysiology of disc degeneration: A Critical Review. J Bone Joint Surg. 90(10)