Management of Psoas Muscle Spasticity in Quadriplegia
Begin with a stepwise approach starting with antispastic positioning, range of motion exercises, and stretching performed several times daily, then escalate to oral baclofen, tizanidine, or dantrolene if spasticity causes pain, hygiene problems, or functional limitations, and consider botulinum toxin injection into the psoas muscle (CT-guided) for focal spasticity refractory to conservative measures. 1
Algorithmic Treatment Approach
First-Line: Physical Modalities
- Antispastic positioning of the hips to reduce flexor tone
- Passive range of motion exercises targeting hip extension, performed multiple times daily
- Stretching protocols focusing on the hip flexors
- Splinting or serial casting if contractures are developing
These interventions should be implemented immediately and continued throughout treatment, as they form the foundation of spasticity management 1.
Second-Line: Oral Pharmacotherapy
When physical modalities alone are insufficient and spasticity results in pain, poor skin hygiene, or decreased function, consider:
- Oral baclofen: First-line oral agent, though may cause significant sedation and has less impact in upper motor neuron lesions compared to other conditions 1
- Tizanidine: Effective for chronic cases with improvement in spasticity and pain without loss of motor strength 1
- Dantrolene: Alternative option with benefit of no cognitive side effects 1
Avoid benzodiazepines (diazepam) as they have deleterious effects on recovery and cause problematic sedation 1.
Third-Line: Focal Interventions for Psoas-Specific Spasticity
When psoas muscle spasticity is the primary problem:
Botulinum toxin injection into the psoas muscle is the preferred focal treatment 2, 3, 4:
- Use CT-guided transabdominal injection technique for accurate targeting 4, 5
- Dose: 3 U/kg body weight per psoas muscle 4
- This approach is safe and effective for reducing hip flexion contracture and improving posture 4
- Particularly useful when psoas spasticity causes low back pain or interferes with positioning 5
Alternative focal treatments include:
- Phenol/alcohol neurolysis for longer-lasting effect 1
- Consider combining psoas injection with treatment of other spastic muscle groups (e.g., hamstrings if crouch gait is present) 4
Fourth-Line: Advanced Interventions
For severe, generalized spasticity unresponsive to above measures:
- Intrathecal baclofen pump: Appropriate for patients who don't respond to other interventions or experience adverse effects from oral medications; can be considered as early as 3-6 months after injury 1, 2
- Neurosurgical procedures (selective dorsal rhizotomy, dorsal root entry zone lesions): Reserved for refractory cases, but carry significant risks including operative complications and unintended spinal cord damage 1
Critical Clinical Considerations
Assess treatment goals specifically: In quadriplegic patients, goals typically focus on:
- Improving comfort and reducing pain
- Facilitating hygiene and positioning
- Easing caregiver burden
- Preventing or slowing musculoskeletal deformities
- Functional improvement is often secondary 6
Monitor for contractures: Patients with quadriplegia and psoas spasticity are at high risk for hip flexion contractures that can render the limb functionless and impede rehabilitation 1. Early aggressive treatment is essential.
Combination therapy is often necessary: Single modality treatment is rarely sufficient in severe spasticity; integrate physical therapy with pharmacologic and/or focal interventions 6, 7.
Common Pitfalls
- Delaying treatment: Early intervention is key to preventing disabling contractures 1
- Using benzodiazepines: These impair recovery and cause excessive sedation 1
- Blind psoas injections: Without CT guidance, accurate targeting of the psoas is difficult and efficacy is reduced 4, 5
- Treating spasticity that doesn't require treatment: Not all spasticity needs intervention; treatment should be goal-directed and meaningful to the patient 8