OLF is indeed a condition more common amoung people of East Asian origins. It is fairly rare but seems to be on the rise. OLF is a thickening and hardening of the ligament that goes between the lamina of the vertebral bones. The lamina form a bony ring around the spinal cord to protect it.
Doctors are trying to figure out what kind of treatment is best for OLF. More studies are being reported but the results are often in conflict from one study to the next. Most experts agree that surgery is required to remove the affected ligament. The goal is to keep the ligament from putting pressure on the spinal cord, thereby preventing neurologic symptoms.
It's not clear if the ligament should be removed at all levels where it is thick and hardened -- or if just the levels that are causing symptoms should be taken out. Sometimes it's very difficult to tell just what levels are affected.
Patients with mild symptoms seem to have a better result by having the OLF removed. Some studies show that when more than two segments are affected the results are less favorable. Early treatment does seem to help the most.