Effective management of hip adductor spasticity: A case report on diagnostic obturator nerve block and botulinum toxin injection

It is important to distinguish spasticity from contracture in patients presenting with upper motor neuron (UMN) syndrome and restricted range of movement (ROM) because treatment strategies differ. We demonstrate how we perform ultrasound-guided obturator nerve (ON) block to distinguish spasticity from contracture in a patient with bilateral hip adductor spasticity secondary to a non-traumatic spinal cord injury. We report here a 26-year-old gentleman with a history of Mycobacterium tuberculosis thoracic spondylodiscitis with spinal cord compression. His neurological status was T6 ASIA impairment scale C and his impairments were spastic paraparesis, neurogenic bowel and neurogenic bladder. He had difficulty with wheelchair transfer and positioning, perineal care as well as intermittent self- catheterization due to severe spasticity of bilateral hip adductors with significantly restricted ROM. Bilateral ON block resulted in clinically significant improvement in spasticity and ROM of the right lower limb but not the left. The effects were similar following intramuscular BTX-A injection of bilateral hip adductors. Ultrasound-guided diagnostic ON block via the distal approach is inexpensive, safe and can be readily performed in clinic setting without the need for sedation or prolonged monitoring. Improvement in MAS score of at least 1 point and ROM of at least 15° following ON block should be used to distinguish hip adductor spasticity from contracture in patients with UMN syndrome and reduced ROM. Diagnostic nerve block allows for greater physician certainty when discussing various treatment options including expedited referral for surgical consult. The findings of this report offer insights into the decision-making process in managing complex presentations of UMN syndrome.