Utilizing International Classification of Diseases Codes to Identify Shoulder Dystocia and Neonatal Brachial Plexus Injury.

BACKGROUND

The utilization of International Classification of Diseases, Ninth or Tenth Revision, (ICD-9/10) coding to identify the incidence of disease is frequently performed in medical research. This study attempts to assess the validity of using ICD-9/10 codes to identify patients with shoulder dystocia (SD) with concurrent neonatal brachial plexus palsy (NBPP).

METHODS

This retrospective cohort study examined patients evaluated at the University of Michigan Brachial Plexus and Peripheral Nerve Program (UM-BP/PN) from 2004 to 2018. We reported the percentage of patients with reported NBPP ICD-9/10 and SD ICD-9/10 discharged at birth who were later diagnosed with NBPP by a specialty clinic by interdisciplinary faculty and staff utilizing physical evaluations and ancillary testing such as such as electrodiagnostics and imaging. The relationship of reported NBPP ICD-9/10, SD ICD-9/10, extent of NBPP nerve involvement, and NBPP persistence at age two years were examined via chi-square or Fischer exact test.

RESULTS

Of the 51 mother-infant dyads with complete birth discharge records evaluated at the UM-BP/PN, 26 (51%) were discharged without an ICD-9/10 code documenting NBPP; of these 26 patients, only four had ICD-9/10 documentation of SD at discharge, which left 22 patients with no ICD-9/10 code documentation of either SD or NBPP (43%). Patients with pan-plexopathy were more likely to be discharged with an NBBP ICD-9/10 code than those infants with upper nerve involvement (77% vs 39%, P < 0.02).

CONCLUSION

Use of ICD-9/10 codes for the identification of NBPP appears to undercount the true incidence. This underestimation is more pronounced for milder forms of NBPP.