foraminal stenosis l5 s1 symptomssevere central canal stenosis l4 l5l4 l5 severe spinal canal stenosisspinal stenosis l4 l5 treatmentl5 stenosis symptomsspinal stenosis l5 s1l4 l5 spinal stenosis surgerysevere spinal stenosis l4 l5bilateral foraminal narrowing l5 s1narrowing l5 s1l5 s1 neural foraminal narrowingl4 l5 foraminal stenosis
