The Impact of Neuroanesthesia Fellowship Training and Anesthesiologist-Surgeon Dyad Volume on Patient Outcomes in Adult Spine Surgery: A Population-Based Study

Introduction: Extensive research has explored the impact of surgeons’ characteristics on patient outcomes; however, the influence of anesthesiologists remains understudied. We performed a population-based retrospective cohort study to investigate the impact of anesthesiologists’ characteristics on in-hospital morbidity after spine surgery. Methods: Adult patients who underwent spine surgery at the London Health Science Centre, Ontario, Canada between January 1, 2010 and June 30, 2023 were included in this study. Data was extracted from the local administrative database. Five anesthesiologists’ characteristics (neuroanesthesia fellowship and residency training backgrounds, surgeon familiarity, annual case volume, and sex) were examined as primary exposures. The primary outcome was composite in-hospital morbidity, encompassing 141 complications. Multivariable logistic regression was performed to assess the association between anesthesiologists’ characteristics and postoperative morbidity with adjustment of patients’ sex, Charlson Comorbidities Index, surgical complexity, and surgeon characteristics. Results: A total of 7692 spine surgeries were included in the analysis. Being a neuroanesthesia fellowship-trained anesthesiologist and high anesthesiologist-surgeon annual dyad volume were associated with reduction in in-hospital comorbidity; adjusted odds ratio (95% CI) of 0.58 (0.49-0.69; P <0.001) and 0.93 (0.91-0.95; P <0.001), respectively. Conversely, anesthesiologist annual case volume, characteristics of residency training and anesthesiologist sex showed only nuanced associations with outcomes. Conclusions: Neuroanesthesia fellowship training and high surgeon-anesthesiologist dyad familiarity was associated with a reduction in in-hospital morbidity following spine surgery. These findings underscore the superiority of structured fellowship education over case exposure experience alone, advocate for dedicated neuroanesthesia teams with high surgeon-anesthesiologist dyad volume and recognize neuroanesthesia as a crucial subspecialty in spine surgery.