Lumbar supports need to be fit by a credentialed medical professional, like an orthotist. These are modular back brace systems so support can be individualized.
For example, if a patient requires a lumbar support after a spinal procedure for a herniated disc then the orthotist can fit a back brace that has removable rigid panels. So initially, the device is functionally rigid and restrictive. Then as the patient heals and progresses through rehabilitation, those rigid panels can be removed. This makes the spinal orthosis more flexible, allowing the user more mobility.
The billing code for this type of brace is usually L0627.