Nocturnal calf cramps is a common complaint in patients with lumbar spinal stenosis. The purpose of this study is to evaluate the effect of botulinum toxin A injection into the gastrocnemius muscle in lumbar spinal stenosis patients receiving conservative therapy. We will compare pain score, insomnia severity, functional ability, patient satisfaction, and neurophysiological variables change using electrical stimulator between control (conservative management for spinal stenosis) and botox group (conservative management for spinal stenosis plus botox injection into the gastrocnemius muscle).

Inclusion Criteria:

1. diagnosed lumbar spinal stenosis with MRI finding
2. nocturnal calf cramps symptoms at least once per week

Exclusion Criteria:

1. electrolyte disorder
2. congenital muscle disease
3. muscle cramps related medication (statins, diuretics, calcium channel blockers, anticonvulsants etc.)
4. cognitive impairments