BACKGROUND: Isthmic spondylolisthesis is a prevalent condition often diagnosed in adults, especially those with low back pain. The main objective of this study was to evaluate the clinical viability of ChatGPT 3.5 and 4.0 by assessing its capacity to produce recommendations consistent with NASS's Evidence-based Clinical Guidelines for adult isthmic spondylolisthesis. METHODS: To achieve the purpose of this study, we used the 2014 NASS Evidence-Based Clinical Guideline for Multidisciplinary Spine Care and presented its 31 questions to ChatGPT 3.5 and ChatGPT 4.0 separately, evaluating their responses for appropriateness and consistency with the guidelines. RESULTS: ChatGPT 3.5 and ChatGPT 4.0 demonstrated concordance rates with the NASS guidelines of 45% and 42%, respectively, with ChatGPT 3.5 showing higher accuracy (91%) for questions with definitive recommendations and both versions showing lower concordance (20%) for questions with no direct recommendations. CONCLUSIONS: Future enhancements should focus on enabling ChatGPT to better reflect the latest evidence and clinical complexities, especially concerning issues that involve medical terms.