I'm a 52-year old construction worker on disability for a back injury. I had surgery to remove a disc in my low back. Now I'm having back, buttock, and thigh pain. The results of the MRI were "normal" for my age and previous injury. Is it possible the problem is coming from higher up in my back?

Possible and probable! Research shows that disc herniation in the upper lumbar spine (L3-L4) doesn't show up the same way a disc problem does located lower in the spine. First, L3-L4 disc herniation occurs more often in older adults (average age: 53 years old).

Second, thigh pain is the most common finding with an upper lumbar disc problem. Leg weakness and decreased knee reflexes are also found.

Third, signs of disc herniation in the upper lumbar spine can be missed with imaging studies. This is because there is a wide ligament along the back side of the lumbar vertebrae. It gets narrower as it goes down toward the lower lumbar segments. The ligament is called the posterior longitudinal ligament (PLL).

The PLL keeps the discs in the upper lumbar spine from pushing backwards into the spinal canal. Instead the damaged or worn disc moves out to the side in a lateral direction. There's less resistance in the lateral region. Radiologists who know about the unusual location of disc fragments in this area are more likely to see this on the image.

You may want to ask your doctor about your suspicions. You can also ask for a second reading (second opinion) of your MRIs.