Our family doctor brushed off his bifid scrotum and H. I took the steps to seek out a dermatologist. When we took Lincoln to her (he was 5m) she and the other 3 derms in the office had never seen a H like his. It is raised in some places and below the skin in others. She took pictures and sent them to University of Minnesota Dermatology director. He responded immediately with the need for an MRI. Within 2 weeks Lincoln had a spinal, head, and lumbar MRI. That is where they found that he had the tethered cord and fluid buildup in his spine. Lincoln had no dimples or hairy patches but Derm said that the H crossing his mid-line was a warning sign of the tethered cord.
Also by the time he had surgery he was 10m and had very little feeling in his left leg. He was a late crawler too.
Our youngest son was born 16m after Lincoln. He has a deep dimple near his behind but an ultrasound at 3m found everything to be normal
With other health issues I think I would push for a check but that is because of our experience.