by Elizabeth Hofheinz, M.P.H., M.Ed.
While solidly established for use in adolescents with idiopathic scoliosis, the famed Lenke classification system cannot be used with adult patients. To evaluate a new radiographic classification system and thus address this gap, researchers from Mr. Sinai Health System and Columbia University in New York City—and Washington University in St. Louis—undertook a novel study. Twelve spine surgeons graded a group of 30 pre-marked cases on two occasions…one week apart. Six of the reviewers were orthopedic surgeons and six were neurosurgeons; eight were attendings and four were fellows.
Providing background on this work was co-author James D. Lin, M.D., who told OSN, “The most common age group for idiopathic scoliosis is the adolescent. In adolescent idiopathic scoliosis (AIS), the Lenke classification is used to describe the different curve types and is used in both clinical and research settings. However, there is no classification system for adult idiopathic scoliosis (AdIS), meaning that there is no way for surgeons or researchers to reliably categorize and communicate the types of curves in adult idiopathic scoliosis.” 
The reason that the Lenke system cannot be used for adults, say the authors, is that “it does not assess the lumbosacral curve or global alignment.”
“This prompted us to create a new classification system for adult idiopathic scoliosis,” said Dr. Lin to OSN. “I had the privilege of training with Dr. Lawrence Lenke, and together we designed the AdIS classification which extends the Lenke AIS classification to apply to adults.”
“The AdIS classification was developed with three primary goals,” say the authors. “(1) to be applicable to adult idiopathic deformities through assessment of the lumbosacral curve and global alignment, (2) to be easily understood and usable by surgeons and trainees by maintaining similarity to the AIS classification, and (3) to have excellent inter- and intrarater reliability by keeping the classification simple and practical.”
The authors indicate that the AdIS differs from the Lenke classification in several ways: “utilization of supine radiographs instead of side-bending radiographs and the creation of the lumbosacral and global alignment modifiers. Three, instead of four, radiographs (standing long-cassette coronal and lateral, and supine coronal) are used to determine classification.”
“The most important takeaway,” states Dr. Lin, “is that this is a highly reliable classification for Adult Idiopathic Scoliosis. It should be familiar to anyone who uses the Lenke classification for AIS.”
The new classification method should facilitate enhanced clinical communication between caregivers, refine treatment, and result in a deeper understanding of patient outcomes.