Variation in Coding Practices for Vestibular Schwannoma Surgery

Abstract

Introduction Nationwide databases are frequently used resources for assessing practice patterns and clinical outcomes. However, analyses based on billing codes may be limited by the inconsistent application of current procedural terminology (CPT) codes to specific operations. We investigated the variability among commonly used CPT codes for vestibular schwannomas resection and sought to identify factors that underlie this variation. Methods The surgical procedure for 274 cases of vestibular schwannoma resections from two institutions was reviewed and classified as retrosigmoid, translabyrinthine, or middle fossa approaches. We then assessed the CPT codes assigned to each case and analyzed their association with surgical approach, surgeons involved, the coding specialty, and year of surgery. We further compared the incidence of CPT codes assigned for vestibular schwannoma surgeries in the American College Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2010 to 2014. Results The majority (65%) of vestibular schwannoma resections within the institutional cohort were billed with skull base approach and/or excision codes, whereas 76% of cases in NSQIP were associated with a single craniotomy for tumor code. The use of skull base codes over the past decade increased within our institutional cohort but remained relatively stable within NSQIP. CPT codes did not consistently reflect the operative approaches for vestibular schwannomas. Conclusion We observed significant variability in coding patterns for vestibular schwannoma surgeries within institutions, surgical practices, and national databases. These results call for discretion in interpretation of data from aggregated billing code-based nationwide databases and suggests a role for institutional standardization of CPT assignments for the same approaches.

Keywords: CPT coding; acoustic neuroma; practice patterns; skull base surgery; vestibular schwannoma.

Fig. 1

Incidence of vestibular schwannoma operations with a single primary code or separate approach and resection codes in ( A ) data from two institutions and ( E ) National Surgical Quality Improvement Program (NSQIP). Among cases with a single craniotomy for tumor resection codes, distribution of submitted codes at ( B ) two institutions and ( F ) within NSQIP. Among cases associated with distinct skull base approach and/or excision codes, distribution of ( C , G ) approach and ( D , H ) excision codes encountered at two profiled institutions and NSQIP. Abbreviation: CPT, common procedural terminology.

Fig. 2

( A ) Incidence of retrosigmoid (76.6%), translabyrinthine (20.4%), and middle fossa (3%) approaches for vestibular schwannoma resection at two academic institutions. ( B ) Comparison of surgical approach (retrosigmoid, translabyrinthine, and middle fossa) for 274 cases encountered at two neurosurgical practices with their assigned common procedural terminology codes, as sorted by single codes for craniotomy for tumor resection, skull base approach, and definitive excision codes.

Fig. 3

( A ) Skull base-specific approach and excision codes became far more commonly utilized than single craniotomy for tumor resection codes at a single institution from 2005 to 2017. ( B ) In comparison, the cumulative incidence of single code for craniotomy for tumor resection versus dual skull base codes for approach/resection has remained relatively stable within the National Surgical Quality Improvement Program (NSQIP) database from 2010 to 2014, while specific ( C ) approach and ( D ) excision codes have varied significantly in utilization over time.