As the spine ages, degenerative changes tend to occur naturally, a progression that complicates attempts to determine whether adjacent segment degeneration (ASD) results from surgical fusion, natural history, or other causes. Many studies in the past support both hypotheses. Although no conclusive etiology exists for ASD, natural history seems to be an important factor. There are initial attempts at classifying ASD viz. by Hilibrand et. al., Louie et al., and Park et al. However, these classification did not withstand the test of time because all these classification systems were solely based on radiological findings. Further, an ideal classification system should be reproducible, valid, reliable, provide guidelines for appropriate treatment, indicate the likelihood of complications, and be of prognostic importance. The lack of a universally accepted classification system makes it difficult to compare and analyse the data emanating from different centres. This would form the basis

for uniform reporting of results.

Hence, the objective of our study is to develop a comprehensive clinico-radiological classification system for Lumbar ASD after lumbar TLIF procedures with internal validation of the classification.