Can a lumbar strain cause minor scoliosis?

Yes: Yes if it causes muscles in the back to spasm.

Yes and no: A true, structural scoliosis can not be caused by a back strain because it is a structural deformity of the spine. That being said, patients who strain or injure their back can often be leaned forward or to the side as a way to ease the pain. This is a form of non structural scoliosis that will resolve as the patient recovers. If it is associate with sciatica is is known as a sciatic scoliosis.