Longitudinal Trends in the Morbidity and Mortality of Skull Base Surgery by Anatomic Subsite

Introduction: Surgical approaches to the skull base have undergone significant refinement in recent decades, with multidisciplinary teams providing efficacious access to complex pathology previously deemed inaccessible. Nevertheless, by nature of the complex anatomy and critical neurovascular structures in this region, the risk of significant mortality and morbidity remains, even at high-volume specialty centers. Although prior studies have investigated predictive factors for morbidity and mortality in skull base surgery via analysis of the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database, the present study was designed to evaluate trends in these outcome measures both longitudinally (2007–2018) and by cranial fossa subsite.

Methods: The NSQIP database was queried from 2007 to 2018 for all patients with CPT codes corresponding to skull base approaches to each cranial fossa subsite (anterior: ACF, middle: MCF, and posterior: PCF). Demographic data including age, gender, BMI, race, and the presence of comorbidities such as diabetes and smoking were noted. Data for each cranial fossa was further subgrouped by time period (2007–2010, 2011–2014, and 2015–2018). Outcome variables of interest were computed for each subsite and time period, including rates of 30-day postoperative mortality, readmission, and reoperation, as well as wound-related complications, nonwound-related complications, and length of stay in days (LOS). Kruskal–Wallis tests and two-sample, two-tailed Wilcoxon's rank-sum tests were performed on all numerical variables due to the nonnormal distribution of the data (α = 0.05).

Results: A total of 1,446 patients met inclusion criteria (mean age: 55.14 ± 15.68 years, 50.76% female). Mortality varied significantly by time period, increasing for MCF and PCF from 2011–2014 to 2015–2018 (0.005 ± 0.006–0.011 ± 0.026 and 0.004 ± 0.008–0.013 ± 0.035, respectively, p < 0.05). Mortality also varied by subsite at all time periods, lowest for MCF and PCF from 2011–2014 and ACF from 2015–2018 (0.005 ± 0.006, 0.004 ± 0.008, and 0.009 ± 0.016, respectively, p < 0.05). No differences in readmission, reoperation, or nonwound-related complication rates were noted among groups. Wound-related complications were more common in ACF and MCF in the 2015 to 2018 period only (13.40 and 11.42%, respectively, p < 0.05), but varied within each subsite over time. Length of stay decreased over time for ACF and MCF when comparing from 2007 to 2011 to 2011 to 2014 and 2015 to 2018, and was the longest for ACF (11.13 ± 10.60, 5.48 ± 5.61, 6.10 ± 7.98, respectively, for ACF and 8.54 ± 9.90, 3.59 ± 5.53, 5.15 ± 7.01, respectively, for MCF, p < 0.05). A multivariate analysis was performed to identify factors predictive of morbidity and mortality by subsite in the 2015 to 2018 time period.

Conclusion: Skull base surgery techniques continue to undergo significant refinement and expansion. This longitudinal analysis of a large, multi-institutional dataset demonstrated that rates of morbidity, mortality, and LOS have changed as the field develops. Moving forward, understanding these trends is critical to identifying areas for further improvement in the care of patients with complex skull base pathology.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
12 February 2021