Overview
Definition:
Neuromuscular scoliosis in Cerebral Palsy (CP) refers to a progressive spinal deformity characterized by a lateral curvature of the spine, often with a rotational component, directly related to the underlying neurological impairment affecting muscle function and balance
This is typically a long C-shaped curve or an S-shaped curve with a high thoracic apex, developing due to muscle imbalance, spasticity, or weakness affecting the trunk muscles and their ability to maintain spinal alignment.
Epidemiology:
Affects approximately 10-25% of individuals with CP, with higher prevalence in those with more severe motor impairment, particularly quadriplegia and diplegia
Incidence increases with age, with the highest risk of progression observed during the adolescent growth spurt
It is more common in non-ambulatory individuals and those with cognitive impairments.
Clinical Significance:
Neuromuscular scoliosis in CP poses significant challenges
Progressive curves can lead to cardiopulmonary compromise, pain, impaired sitting balance, difficulty with hygiene, and increased risk of pressure sores
Early recognition and appropriate management are crucial to optimize functional outcomes, improve quality of life, and prevent severe complications, making it a critical topic for pediatric and orthopedic trainees preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Uneven shoulder height
Prominent scapula
Uneven hip level or asymmetry of the iliac crests
Head tilt or misalignment
Back pain or discomfort, especially with progression
Visible spinal curvature
Difficulty sitting upright or maintaining posture
Symptoms may be subtle initially and become more apparent with growth or increasing severity of motor impairment.
Signs:
Asymmetrical shoulder or hip height
Rib cage asymmetry
Waist asymmetry (one flank appears larger than the other)
Uneven muscle bulk along the spine
Limited trunk range of motion
In severe cases, a visible gibbus (hump) may be present
Assessment of motor function, including gross motor function classification system (GMFCS) level, is essential.
Diagnostic Criteria:
Diagnosis is primarily clinical and radiographic
A Cobb angle of greater than 10 degrees on a standing spinal radiograph in an individual with CP is diagnostic
Radiographs should include anteroposterior (AP) and lateral views of the entire spine, and potentially an AP pelvis to assess hip migration
MRI of the spine may be indicated to rule out associated spinal cord abnormalities, though it is not routinely required for scoliosis assessment alone.
Diagnostic Approach
History Taking:
Detailed birth history and developmental milestones
Assessment of motor function and GMFCS level
History of assistive devices used (wheelchair, orthotics)
Presence of pain, respiratory issues, or gastrointestinal symptoms
Family history of scoliosis or neuromuscular disorders
Previous orthopedic interventions or brace use.
Physical Examination:
Observe standing and sitting posture for symmetry
Assess shoulder height, scapular position, iliac crest height, and waist asymmetry
Perform forward bending test (Adam's forward bend test) to assess for rib hump or flank asymmetry, although its utility in neuromuscular scoliosis is debated
Evaluate trunk muscle strength and tone
Assess for any neurological deficits or sensory disturbances
Examine hips for subluxation or dislocation
Assess for contractures.
Investigations:
Initial investigation is a standing AP and lateral full-spine radiograph
Measurement of Cobb angle to quantify the curvature
Assessment of pelvic obliquity and spinal balance (pelvic tilt and lumbar lordosis/kyphosis)
Radiographs of the hips to assess for subluxation or dislocation (pelvic abduction and supine AP views)
Pulmonary function tests (PFTs) may be indicated for curves exceeding 50 degrees or with significant pulmonary symptoms
Nutritional status assessment (BMI, albumin).
Differential Diagnosis:
Idiopathic scoliosis, congenital scoliosis, other neuromuscular conditions (e.g., muscular dystrophy, spinal muscular atrophy), syndromic scoliosis
Distinguishing features include the typical C-shaped, long thoracic curve in CP, often associated with significant pelvic obliquity, and the absence of vertebral anomalies typically seen in congenital scoliosis
History and neurological examination are key to differentiating.
Management
Initial Management:
For mild curves (<20-25 degrees) with slow progression and adequate sitting balance, observation with regular radiographic follow-up (every 4-6 months) is appropriate
For more significant curves or rapid progression, interventions aim to halt progression and improve trunk balance
Non-operative management is often attempted first, especially in younger children or those with potential for ambulation.
Non Operative Management:
Bracing: Dynamic or static thoracolumbosacral orthoses (TLSO) may be used to provide external support, improve sitting posture, and potentially slow progression
However, the effectiveness of bracing in preventing progression of neuromuscular scoliosis, particularly in rapidly progressing curves, is controversial, with some studies showing limited benefit
Proper fitting and adherence are crucial for any potential benefit.
Surgical Management:
Indications for surgery include progressive curves greater than 40-50 degrees in a growing child, curves exceeding 50-60 degrees in adults, significant pelvic obliquity, cardiopulmonary compromise, or severe pain
Spinal fusion with instrumentation (e.g., posterior segmental instrumentation) is the gold standard
Goals are to correct the curve, achieve spinal balance, prevent further progression, and improve sitting posture.
Supportive Care:
Nutritional support is vital, especially pre- and post-operatively
Physiotherapy and occupational therapy to optimize function, mobility, and seating posture
Regular respiratory monitoring, particularly for larger curves
Management of spasticity with oral medications or botulinum toxin injections if contributing to the deformity
Pressure sore prevention and management.
Complications
Early Complications:
Wound infection
Hardware failure (loosening, breakage)
Pseudarthrosis (non-union)
Neurological deficit (rare)
Blood loss
Pulmonary complications (atelectasis, pneumonia).
Late Complications:
Failure of fusion
Curve progression above or below the fused segment
Chronic pain
Hardware irritation
Increased pelvic obliquity
Cardiopulmonary deterioration if fusion is inadequate or fails
Skin breakdown over hardware.
Prevention Strategies:
Strict aseptic technique during surgery
Careful surgical planning and execution
Use of appropriate instrumentation and bone graft
Post-operative immobilization and mobilization protocols
Aggressive pulmonary toilet
Good nutritional status
Regular follow-up to monitor for signs of failure.
Prognosis
Factors Affecting Prognosis:
Severity of the underlying CP (GMFCS level)
Age at diagnosis and treatment
Rate of curve progression
Degree of pelvic obliquity
Presence of associated medical conditions (respiratory, cardiac, nutritional)
Surgical technique and quality of fusion
Compliance with post-operative care.
Outcomes:
Successful spinal fusion aims to halt curve progression, improve trunk balance and sitting posture, and reduce the risk of cardiopulmonary complications
In non-ambulatory individuals, improved sitting posture can enhance independence and reduce the risk of pressure sores and aspiration
For ambulatory individuals, it preserves mobility
However, long-term outcomes can be variable, and some degree of pain or functional limitation may persist.
Follow Up:
Post-operative follow-up involves serial radiographs to assess fusion and alignment (typically at 3, 6, 12 months, and then annually until skeletal maturity)
Clinical assessment of posture, sitting balance, and functional status
Monitoring for complications
For non-operative management, regular clinical and radiographic assessment is crucial to detect progression and guide treatment decisions.
Key Points
Exam Focus:
Understand the high prevalence of neuromuscular scoliosis in severe CP
Differentiate it from idiopathic scoliosis based on curve pattern and progression
Recognize indications for bracing versus surgery
Know the surgical goals: curve correction, spinal balance, and prevention of progression
Be aware of complications of both bracing and surgery
The GMFCS level is a critical predictor of progression and surgical need.
Clinical Pearls:
Always assess sitting balance and pelvic obliquity alongside spinal curvature
Early recognition of rapid progression is key to timely intervention
Discuss goals of care with families
brace effectiveness can be debated, but patient comfort and positioning are paramount
Surgical outcomes are improved with adequate fusion and attention to spinal balance
Consider the impact of scoliosis on overall care, including breathing and digestion.
Common Mistakes:
Underestimating the rate of progression in growing children with severe CP
Relying solely on Cobb angle without considering pelvic obliquity and spinal balance
Inappropriate selection of bracing for rapidly progressing curves
Delayed surgical referral when non-operative management fails
Inadequate post-operative follow-up leading to undetected complications or failed fusion.