With scoliosis, at what point will harrington rods be helpful?

50 degrees. Generally surgery is recommended for curves that are greater than 50 degrees. While we still use dual rod constructs, they are no longer harrington rods. Scoliosis over 45- 50 degrees is said to progress a degree a year in maturity. At 90-100 degrees respiratory function is impacted. Lesser scoliosis does not typically progress.
Not Harrington. Most current spine surgeons do not use harrington instrumentation, since there are better corrective techniques with modern instrumentation. With a major curve over 40 degrees, especially with curve progression, most surgeons would advocate corrective fusion.