Approach to Backache
Incidence
Causes Mechanical Failure
Nerve root compression
Rarer causes
Non-orthopaedic
Natural history of lumbar disc disease
Theory of spinal degeneration
1st stage - dysfunction
2nd stage - instability
Final stage - stabilization
Pain transmitting structures
Results of surgery
Why surgery often fails
Investigations
Special Investigations
Treatment Modalities
Indications for surgery in discogenic disease
Lumbar Spinal Stenosis
Ankylosing spondylitis
Non-specific (mechanical) low back pain
Incidence
- 80% of the population affected at some time in life
- 40% also has sciatica
- most frequent claim for disability in USA (1990) involved back disorders
- approximately 19%
- enormous financial costs
- loss of productivity
- Nachemson (1993) - cost of LBP was 5% of Sweden’s GNP
- clear correlation between welfare benefits & stay away from work
Causes Mechanical Failure
Gross
- i.e. plain X ray diagnosis
- spondylolisthesis
- scoliosis with facet joint arthritis
- trauma #’s & dislocations
- spinal osteoporosis
Subtle
- instability - like to rest
- disc pathology - discogram or MRI diagnosis
- ligament & facet joint capsule sprains & strains
- facet arthrosis - like to move
- diagnosed on facet arthrography, CT
Nerve root compression
- disc prolapse
- stenosis
Rarer causes
- inflammation
- i.e. ankylosing spondylitis
- infection
- metabolic
- neoplastic
- malignant - primary or secondaries
- benign
Non-orthopaedic
- gynae
- intra-abdominal
- vascular
Natural history of lumbar disc disease
- natural history of the disc sy. is towards resolution
- Holmes & Rothman - 90% resolve spontaneously within 3 months</li
- Singer - similar findings
- Weber (Spine 1983) - results of disc dx treated operatively at 1 year was far better than those treated non-operatively BUT, at 4 & 10 year follow-up, the results were the same
- neurological results improved just as well in the conservatively treated group as the operative group
- natural course of herniated discs - decrease in size (serial CT scans) - Thelander & others
Theory of spinal degeneration
- all spines degenerate
- present methods of treatment are for symptomatic relief, not for a cure
- degenerative process divided into three separate stages
1st stage - dysfunction
- age group - 15-45 years
- tears in the disc anulus & localized synovitis of the facet joints
- familial predisposition to lumbar disc herniation in patients who had herniation before age 21 years
2nd stage - instability
- 35-70-year-old patients
- internal disruption of the disc progressive disc resorption, degeneration of the facet joints with capsular laxity, subluxation & joint erosion
Final stage - stabilization
- patients older than 60 years
- development of hypertrophic bone about the disc and facet joints
- leads to segmental stiffening or frank ankylosis
- each spinal segment degenerates at a different rate
- one level is in dysfunction, another may be entering stabilization stage
- disc herniation a complication of disc degeneration in dysfunction & instability stages
- spinal stenosis from degenerative arthritis is a complication of bony overgrowth compromising neural tissue in the late instability & early stabilization stages
- males were found to have more degeneration than females
- L4-5 & L3-4 disc levels showed the greatest degree of disc degeneration
Pain transmitting structures
- at the level of the intervertebral foramen is the dorsal root ganglion
- distal to the ganglion three distinct branches arise from the dorsal root
Ventral ramus
- supplies all structures ventral to the neural canal
Sinu-vertebral nerve
- originates from the ventral ramus
- innervating posterior aspect of disc, vertebral bodies & posterior longitudinal ligament
Dorsal ramus
- three branches
- innervate the structures dorsal to the neural canal
- posterior musculature and skin
- facet joint
Results of surgery
- failure rate of surgery for pain relief d/t disc herniation is high (reported by several authors)
- significant morbidity also present post-op
Why surgery often fails
- main cause of surgical failure = poor patient selection
- inaccurate diagnosis
- back pain & sciatica can originate from a number of sites
- X rays, CT scans & MRI’s are only of relevance if the findings are supported by clinical findings
- to operate on the basis of special investigations only is unacceptable
- must also remember:
- diabetes can mimic a herniated disc
- ischaemia of the cauda equina & nerve roots are a cause of intermittent claudication
- psychogenic factors
Investigations
- straight x-ray
- blood tests
- myelogram
- CT scan
- MRI scan
- bone scan
Special investigations
- CT & MRI
- low specificity: 30% of the N population have positive scans which are of no importance
- EMG
- has a very high accuracy: helpful test when surgery is considered
- fibrinolytic activity test
- a low fibrinolytic response favours a bad surgical result
- the plasminogen activator inhibitor 1 test is sufficient to assess this
- discogram
- valuable pre-operative examination
Treatment modalities
- manipulation
- if it has a role
- traction
- no proof that it has a beneficial role
- chemonucleolysis
- unpopular because of severe complications:
- transverse myelitis
- allergic reactions
- persisting attacks of muscle spasm
- facet joint infiltration
- useful, may exclude a facet joint arthropathy as a cause of pain
- epidural injections (cortisone)
- recommended
- spinal corsets
- have a place in the treatment of low backache
Indications for surgery in discogenic disease
- all compatible
- symptom complex
- clinical signs
- investigations
- advanced neuro deficit
- progressive neuro deficit
- sphincter involvement
- incapacitating pain
- failed conservative management
Lumbar Spinal Stenosis
- elderly patients
- smaller than normal spinal canal + spondylosis
- local pain in back
- relief by flexion
- claudication of the cauda equina
- random neurological signs in legs
- good surgical outcome
Ankylosing spondylitis
- young males
- non-specific “lumbago” symptoms
- morning stiffness
- typical radiological signs
- later signs
- poker spine
- respiratory difficulty
- cardiac and other systems
Non-specific (mechanical) low back pain
- site
- discomfort across lower back
- central pain, usually over L5
- leg pain or paraesthesia within “sciatic” distribution
- unilateral or bilateral buttock or lateral back pain
- character
- episodic or cyclical pain in the middle years of life
- arises from L3-S 1
- early morning stiffness or pain eases when patient is up and about
- relation to posture
- often aggravated by sitting or standing still
- eased by walking normally
- pain that is greatly aggravated by walking raises the possibility of vascular claudication or spinal or lateral canal stenosis