RESUMEN
STUDY DESIGN: Meta-analysis of individual patient data. OBJECTIVE: To date, the progression pattern of cauda equina syndrome (CES) has not been summarized. This study assessed individual patient data from CES cases, investigated the CES progression pattern to help clinicians provide timely diagnoses. SUMMARY OF BACKGROUND DATA: Because there were few randomized controlled trials about CES, our research was based on case reports of CES with detailed medical history. METHODS: We searched English literature regarding CES in the PubMed database. We included a total of 198 publications involving 264 cases that met the inclusion criteria. The occurrence order of symptoms was determined by reviewing patients' medical histories, and the progression pattern of CES was analyzed using sequential pattern mining. Finally, we summarized and reassessed the current timing of CES diagnosis. RESULTS: Result of sequential pattern mining demonstrated that the progression process of CES could be divided into 3 stages: early stage of CES (CESE), with bilateral peripheral nerve dysfunction characterized by progressive sensory-motor defects from unilateral to bilateral in lower extremities; incomplete CES, with reduction of sphincter functions; and CES in retention, with sphincter dysfunction. Among all the cases, 81.08% (180 cases) were diagnosed at the stage of incomplete CES or CES in retention, in which 99.4% (179 cases) had experienced CESE without being diagnosed. CONCLUSION: The characteristic progressive sensory-motor CESE defects in lower extremities marked CES onset. Instead of waiting for the onset of sphincter function abnormalities, CES should be diagnosed when the CESE symptoms manifest.