Aetiology
- Typically develops after age 50 years
- Factors implicated in development of degenerative scoliosis:
- Osteoporosis
- Degenerative disc disease
- Osteoarthritis
- Stenosis
- Endochondral abnormalities
- Compression fractures
- Facet tropism
- Lateral listhesis
- Essentially 2 pathophysiologic processes result in scoliotic deformity:
- Isolated degenerative arthritis of posterior facet joints to point of incompetence, when anterolisthesis develops
- Asymmetric collapse of disc & asymmetric incompetence & hypertrophy of facet joints, leading to a lateral & rotational deformity; result is deformity combined with varying degrees of central lateral recess & foraminal stenosis
Natural History
- Characterised by minimal structural vertebral deformities, advanced degenerative changes, & a predominance of lower lumbar curves
- Distinguished from adult idiopathic scoliosis by radiographic confirmation of a straight spine during adulthood with subsequent development of a degenerative curve
- Unilateral radicular symptoms much more common on side of concavity of deformity
- Risk factors for curve progression:
Imaging
- Plain radiographs:
- Patient standing without bending at knees or hips, using full-spine films to assess overall spinal balance (including EOS imaging)
- Evaluated for
- Curve location
- Number of levels involved
- Direction of curve
- Magnitude of curve
- Risk factors for progression
- Lateral listhesis
- Apical rotation
- Height of residual disk spaces throughout deformity
- Spondylolisthesis
- Osteoporotic compression fractures
- MRI:
- Spinal stenosis
Management
- Non-operative:
- Physiotherapy
- Aerobic exercise to improve cardiovascular reserve while decreasing pain & increasing function
- Trunk stabilisation
- NSAIDs
- Paracetamol-based analgesic
- Pain unit consultation
- § Tricyclic antidepressants
- Night pain & can decrease neurogenic pain
- § Gabapentin/Pregabalin
- May help in decreasing neurogenic pain
- § Narcotic medications
- § Tricyclic antidepressants
- Spinal orthoses
- Used primarily to control symptoms & do not stop progression of curve
- Potential for pain relief must be balanced with discomfort of wearing a brace & potential for trunk muscle deconditioning
- If a patient is able to function better with a brace than without, its use may be justified
- Patients who use a brace should exercise regularly to avoid further deconditioning
- Choice of orthosis should be based on perceived goal
- Rigid lumbosacral orthosis may provide reasonable function for some patients with degenerative scoliosis
- Rigid thoracolumbosacral orthosis typically would be used to help rib-to-pelvis impingement
- Transcutaneous electrical nerve stimulation (TENS)
- Epidural steroids, facet blocks, nerve-root blocks
- Useful for diagnostic purposes in addition to their short-term therapeutic benefit
- Physiotherapy
- Operative:
- Indications
- Severe, refractory pain limiting ADL’s
- Progressive deformity
- Progressive neurologic deficits
- Spinal imbalance
- Decompression
- Decompression & fusion
- Most patients should be treated with decompression & fusion with bilateral fixation devices
- Decompression alone could lead to further collapse, instability, & increased lower back & nerve pain
- 85% good to excellent results in terms of little to no lower extremity pain post-operatively
- Indications
Surgical Recommendations
- Decompression with or without fusion:
- Most surgical candidates present with symptoms of neurogenic claudication, which necessitates decompression
- If epidural injections provide temporary pain relief, & disc spaces through deformity are severely collapsed with no lateral listhesis or anterolisthesis, decompression alone or decompression with posterior spinal fusion without fixation devices can be considered
- If more evidence of spinal instability is present, need for arthrodesis is clearer
- Decompression & instrumented fusion:
- In a patient with lateral listhesis >5mm, anterolisthesis, or residual disc space height with degenerative scoliosis, posterior fusion with instrumentation is reasonable
- Technique also should be considered when substantial back pain accompanies neurogenic claudication
- If no coronal or sagittal imbalance, fusion can be limited to levels decompressed
- Fusion to sacrum is rarely indicated
- If clinically significant stenosis involves L5-S1 level, a laminectomy of L5 can be done with a fusion to L5
- If clinically significant spinal stenosis as well as a deformity, such as spondylolisthesis or severe foraminal stenosis at L5-S1 level, then fusion of L5 with S1 is indicated
- Interbody fusion at L5-S1 level should also be considered, either through a posterior or separate anterior procedure, to structurally augment L5-S1 level & speed fusion
- Deformity reconstruction:
- Observation warranted with isolated or progressive deformity with minimal pain & well-maintained spinal balance
- With mechanical back pain +/- neurogenic claudication, deformity is usually one of sagittal imbalance with a lumbar flat back, but it also may include elements of coronal imbalance
- Decompression alone in this situation has a very high failure rate
- Surgical plan should assure spinal balance &, in most cases, will require fusion to the sacrum
- If deformity involves L5-S1 level, reconstruction must incorporate this level to assure spinal balance
- Reconstructions often require either combined anterior & posterior approaches, multilevel posterior interbody procedures, or posterior osteotomies with fixation devices
- Complications:
- Occur in 20 to 40% & include
- Pseudarthrosis
- Wound infection
- Paresthesias
- Radiculopathy
- CSF fistulas
- Hardware failure
- Compression fractures
- Urinary tract infection
- DVT / PE
- Myocardial infarction
- Adult respiratory distress syndrome
- When junctional stenosis, degenerative disc disease, & progressive kyphosis proximal to fusion occur, extending proximal fusion in upper thoracic spine is justified
- Fusion done 1 to 2 levels proximal to decompressed segments may ease transition to normal spine
- Occur in 20 to 40% & include