The National Upper Cervical Chiropractic Association, NUCCA, has developed a highly advanced procedure over the last half century that is an extremely precise and gentle technique unlike any other kind of allopathic or holistic care. This technique is exclusively practiced by less than 1% of all chiropractors in the United States and approximately 300 chiropractors in the entire World. The National Upper Cervical Chiropractic Association, NUCCA, has developed a highly advanced procedure over the last half century that is an extremely precise and gentle technique unlike any other kind of allopathic or holistic care. This technique is exclusively practiced by less than 1% of all chiropractors in the United States and approximately 300 chiropractors in the entire World.