What is a Slipped Disc (Disc Herniation)?
The spinal discs lie in between the vertebrae (bones) of the spine. The purpose of the spinal discs is to act as a shock absorber and to allow a small range of mobility between adjacent spinal vertebrae. There are 23 spinal discs in the spine. The discs are composed of a tough outer ring (annulus fibrosis) and a soft jelly-like core (nucleus pulposus). With a disc herniation (slipped disc), both layers of the disc degenerate to a point that the jelly-like core can escape into the spinal canal and compress surrounding nerves. This nerve root compression can explain many of the symptoms associated with a slipped disc, such as pain in the thigh & also numbness, tingling or pins and needles in the legs or feet. Many people will tell you that they had a ‘slipped disc’ and will commonly report how they had somebody ‘put it back in place’. This is not quite correct, as the jelly-like spinal disc, once it has herniated, cannot be put back into place. The healing process for a real disc herniation (slipped disc) will take a period of time & the disc cannot be popped in or out.
There is some debate as to whether the symptoms of a slipped disc come about due to direct compression of the disc against the nerve root or whether there is an inflammatory response that takes place in response to a disc herniation that in turn stimulates the surrounding nerves. This inflammation can increase the pressure from the disc bulge on the nerve root. As the inflammatory response is brought under control then the symptoms may subside.
Spinal Disc Injuries (“Slipped Disc”)
Degenerative disc disease, prolapsed intervertebral disc, pinched nerve and sciatica are frequently used terms that all refer to injuries of the spinal disc. In fact another frequently but rather incorrectly used term is ‘slipped disc’.
Located between adjacent vertebrae, the intervertebral discs are present in the cervical, thoracic and lumbar (low back) regions of the spine. The intervertebral discs in the cervical spine (neck) allow for flexibility while those in the thoracic and lumbar spine participate in force transmission. The discs also act as shock absorbers. A well-nourished hydrated disc maintains a healthy space between adjacent spinal bones. This prevents any compression of the spinal nerves that exit through the intervertebral foramen (opening at the side, where two vertebrae meet).
Structure of the disc
The intervertebral disc can be imagined as a small fluid filled balloon lodged between adjacent vertebrae. It has two parts- a soft inner nucleus pulposus and a tough outer annulus fibrosus. The disc is attached to the vertebrae above and below and hence cannot ‘slip’. Since the disc is compressible, it allows spinal movement.
However, just like the rest of the body, the discs are also prone to degeneration. When the disc dehydrates as part of the degenerative process, the disc height reduces. This brings the vertebrae closer, narrowing the intervertebral foramen. This may cause pinching of the nerves exiting through them.
The discs in the lower cervical spine (C5-C6 and C6-C7) are vulnerable to injury as these segments have a high degree of mobility. The lower lumbar spine (L4-L5 and L5-S1) are the most commonly injured spinal discs as they have a significant role in weight bearing and are situated at the junction between the stable pelvis and mobile low back.
Causes of disc injuries
- Age related degenerative changes
- Overuse injury (repeated bending)
- Trauma causing flexion-rotation injury
- Incorrect lifting techniques
- Poor posture
- Poor physical fitness
- Prolonged sitting
- Lack of regular exercise
As the disc degenerates it passes through various stages.
Disc bulge – This is the initial stage wherein the nucleus (core) of the disc presses against the weakened outer annulus fibrosus. The disc is deformed but intact. It is contained within the margins of the vertebral body by the posterior longitudinal ligament (a long ligament that runs through the length of the spine). At this stage the patient may complain of a dull pain in the neck or low back.
Disc protrusion – In this phase, the disc nucleus protrudes through torn inner fibres of the annulus fibrosus. The outer layers are still intact. The disc is severely deformed. At this stage the disc may impinge on some nerve and the patient may complain of neck or back pain that radiates into the arm or leg.
Disc extrusion (prolapse) – In this phase, there is complete rupture of the annulus fibrosus and part of the nucleus pulposus slips out. There may be compression of the nerves that lie close to the disc. The patient experiences severe neck/back pain with accompanying arm/leg pain. The muscles supplied by the affected nerve may show weakness.
Disc herniation – At this stage the entire nucleus pulposus seeps out of the ruptured annulus fibrosus and lies outside the disc. The surrounding nerves are compressed leading to pain, numbness and tingling in the arm or leg. The muscles supplied by the affected nerve may show weakness. In severe cases there may be foot drop where the patient cannot lift the foot properly.
Usually the disc prolapse occurs to the back & outer edge of the disc. However, if the prolapse occurs more centrally, there may be compression of the spinal cord. This is known as cauda equina syndrome, which is a medical emergency.
Symptoms of a disc injury
- Dull or sharp pain in neck/low back
- Neck/low back pain aggravated by bending, sneezing or coughing
- Severe spasm of neck/low back muscles
- Cervical radiculopathy – pain, burning, tingling, and numbness in the arm
- Sciatica – pain, burning, tingling, and numbness in the leg
- Weakness in the muscles of the arm/leg that are supplied by the affected nerve
Treatment of “slipped disc” injuries
Naas physiotherapy clinic specialises in the treatment and rehabilitation of people with spinal disc injuries. It usually takes around 6-12 weeks of rehabilitation to return normal activities of daily living. Only in rare cases of severe disc injuries with cauda equina syndrome (compression of the spinal cord) would patients need to undergo spinal fusion or disc replacement surgery. Naas Physio Clinic also offers intensive post-operative rehabilitation in such cases.
Pain: It is the characteristic feature of a spinal disc injury. At times the pain may be severe enough to preclude activity. A patient with cervical spine disc prolapse usually complains of pain in the neck extending up to the shoulder and the arm. This pain is known to increase while coughing or sneezing.
Patients with a lumbar disc prolapse report pain in the low back and buttock. The low back pain also increases while bending, lifting, sneezing or coughing.
Gentle spinal mobilisations, activity modification, ergonomic advice and proper lifting techniques help to reduce the pain.
Radiating pain: The herniated disc compresses the nearby spinal nerves causing radiating pain. A person with cervical disc herniation/prolapse will notice pain, numbness and tingling going down one arm (dermatome). Similarly a patient with lumbar disc prolapse/herniation complains of numbness and tingling down one leg.
Radiating pain in the arm/leg due to a pinched nerve can be managed through intermittent cervical or lumbar traction and neural mobilisation techniques.
Muscle spasm and stiffness: The tissues around the disc herniation site will often develop spasm and stiffness. This can often be a driver of part of the symptoms experienced by the patient.
Deep soft tissue massage, muscle energy techniques, joint mobilisation and gentle stretching significantly reduce the spasm and stiffness.
Muscle weakness: In longstanding cases of nerve compression due to cervical disc prolapse, there may be muscle weakness in the arm & hand making it difficult to hold objects. Similarly compression of spinal nerves due to a lumbar disc prolapse may make it difficult for the person to walk or climb stairs.
Selective strengthening of the affected muscles through progressive resisted exercises can help to overcome muscle weakness.
Preventing relapse: Dynamic lumbar stabilisation exercises form the core of the rehab program for a lumbar disc prolapse. Strengthening of the main core muscles – multifidus and transversus abdominis is crucial for preventing recurrence of the condition. Similarly a great emphasis is placed on strengthening of deep stabilizing muscles of the neck while managing a case of cervical disc prolapse.
Cauda equina syndrome: A central disc prolapse in the lumbar (low back) region can cause compression of the spinal cord. In such cases the patient may complain of loss of sensation in both legs, loss of bladder control, and instability while walking.
This needs urgent medical attention.
Back to work after a spinal disc injury
At Naas Physiotherapy clinic, the focus is on developing a personalised treatment plan for each patient. As these injuries take several weeks to heal, compliance to the rehab plan is important. The ‘benefits of movement and an active lifestyle’ and the ‘ill effects of immobility’ in such cases is explained to the patient. Techniques used for treatment include:
- Activity modification guidance/Ergonomic advice for lifting and carrying
- Advice for environmental modification (if needed)
- Joint mobilisation and manipulation
- Manual therapy
- Deep soft tissue massage
- Myofascial release
- Muscle energy technique
- Selective stretching
- Progressive resisted exercises
- Core strengthening – Dynamic lumbar stabilisation
- Complete biomechanical analysis
- Posture and gait analysis
- Correction of muscle strength imbalance
- Balance and proprioceptive exercises
- Post-operative rehabilitation after spinal surgery
Management of a “Slipped Disc”
It is important to realise that although the symptoms of a disc herniation may come on very suddenly, the underlying changes that predispose to back pain develop over several years. Factors such as poor posture & deconditioned trunk muscles can predispose the spine to more rapid degenerative changes which can eventually give rise to disc herniations. It would be logical that if the underlying cause of the disc herniation is not addressed then this may predispose to future spine or disc injury. This is borne out by research demonstrating a massive reduction in low back re-injury rates in those who undergo specific rehabilitation programmes. After 12 months re-injury rates were 30% in those who had undergone a rehabilitation programme versus 80% in those who had not.
A disc herniation should be carefully monitored and rehabilitated under professional guidance. Occasionally, surgery may be required for a disc herniation but practice guidelines suggest that this should only take place if there is no improvement in symptoms over a period of months and in cases where there are changes in bowel or bladder habits or progressive neurological deficits.
To find out more, contact Naas Physio Clinic on:
(045) 874 682
or email us at firstname.lastname@example.org
For further information on conditions treated go to: https://www.physioclinic.ie/chiropractor-naas/