Nevin Manimala Statistics

Facial Trauma Operative Volume Demonstrates Consistent and Significant Yearly Periodicity

J Oral Maxillofac Surg. 2022 Dec 29:S0278-2391(22)01104-1. doi: 10.1016/j.joms.2022.12.007. Online ahead of print.


PURPOSE: Facial trauma requiring operative care increases during the summer and fall months, which is colloquially referred to as “trauma season.” The purpose of this study is to determine if there is a quantifiable and statistically significant yearly periodicity of operative facial trauma volume.

MATERIALS AND METHODS: To confirm the existence and quantify the magnitude of trauma season, we conducted a retrospective cohort study. The Plastic Surgery divisional billing database was queried for Current Procedural Terminology (CPT) codes related to acute facial trauma. The outcome variable is monthly CPT code volume and calendar month is the predictor. Monthly CPT volume was tabulated for 120 consecutive months. Raw data were plotted as a time series and transformed as a ratio to the moving average. Autocorrelation was applied to the transformed dataset to detect yearly periodicity. Multivariable modeling quantified the proportion of volume variability (R2) attributable to yearly periodicity. Subanalysis assessed presence and strength of periodicity in 4 age groups. Patient identifiers, demographic information, surgeon, and date of surgery were collected as covariates.

RESULTS: One thousand six hundred fifty eight CPT codes obtained through Plastic Surgery billing records were included. Mean age at presentation was 32.5 ± 16.3 years (range = 85.05). Monthly trauma-related CPT volume was highest in June-September and lowest in December-February. Time series analysis revealed yearly oscillation, in addition to a growth trend. Autocorrelation revealed statistically significant positive and negative peaks at a lag of 12 and 6 months, respectively, confirming the presence of yearly periodicity. Multivariable linear modeling revealed R2 attributable to periodicity of 0.23 (P = .008). Periodicity was strongest in younger populations and weaker in older populations. R2 = 0.25 for ages 0-17 years, R2 = 0.18 for ages 18-44 years, R2 = 0.16 for ages 45-64 years, and R2 = 0.034 for ages ≥ 65 years.

CONCLUSION: Operative facial trauma volumes peak in the summer and early fall and reach a winter nadir. This periodicity is statistically significant and accounts for 23% of overall trauma volume variability at our Level 1 trauma hospital. Younger patients drive the majority of this effect. Our findings have implications for operative block time and personnel allocation, in addition to expectation management over the course of the year.

PMID:36587931 | DOI:10.1016/j.joms.2022.12.007

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