My husband says he feels pressure on his sciatic nerve. he also feels numbness from his waist down on his left side occasionally. what could this be?

Herniated disk : The. Most common cause of acute sciatica in a young person is an acute herniated disk in the lumbar spine. Best to see your primary doctor for evaluation and imaging. Luckily, most of these resolve with time and very few will need surgery.

Lumbar spine issues: Lumbar disc problems or stenosis (narrowing of the spinal canal) are very common causes for numbness in one hip and leg. Examination by a neurologist, physical medicine specialist, neurosurgeon or spine surgeon would be helpful.