The Prevalence and Characteristics of Operative Tandem Spinal Stenosis

STUDY DESIGN: A retrospective database study. OBJECTIVE: To clarify the prevalence and characteristics of Operative Tandem Spinal Stenosis (O-TSS)-the condition requiring surgery in at least two different spinal regions (cervical, thoracic, or lumbosacral)-focusing on patients with a history of thoracic spine surgery. SUMMARY OF BACKGROUND DATA: While repeat surgery for adjacent or same-level disease is well-documented, the characteristics of patients requiring surgery in different spinal regions-defined here as O-TSS-are not well understood, particularly regarding the thoracic spine due to lower surgical volumes. METHODS: We analyzed 4,484 patients who underwent primary surgery for degenerative spinal disease at a single institution over a 20-year period (2000-2019). O-TSS was defined as a history of surgery in ≥2 different spinal regions (cervical, thoracic, or lumbosacral), including both concurrent and subsequent identification of multi-regional lesions. Prevalence and surgical intervals were analyzed across cohorts. RESULTS: The overall prevalence of O-TSS was 5.0% (224/4,484; 95% CI, 4.4%-5.7%). The prevalence among patients with a history of thoracic surgery was a striking 42.0% (95% CI, 34.7%-49.7%), significantly higher than in the cervical (16.0%) and lumbosacral (6.0%) cohorts (P<0.0001). Intriguingly, while older age and male sex were associated with O-TSS in the cervical or lumbosacral cohorts, these factors were not significant in the thoracic cohort. Furthermore, the high prevalence in thoracic patients was consistent across different pathologies (myelopathy, OPLL/OLF, and disc herniation). The mean interval to a subsequent surgery was shortest after a thoracic procedure. CONCLUSION: Patients with a history of degenerative thoracic spine surgery represent a unique population with a significantly high prevalence of O-TSS (42.0%). This high prevalence appears to be independent of patient demographics or the specific underlying pathology. Maintaining a high index of clinical suspicion for additional lesions is warranted in this specific population.