Strengths and limitations of International Classification of Disease Ninth Revision Clinical Modification codes in defining cervical spine surgery.

Study Design: Retrospective study.

Objective: To evaluate the sensitivity and specificity of International Classification of Disease Ninth Revision Clinical Modification (ICD9-CM) hospital discharge codes to define degenerative cervical spine surgery in comparison to patient operative notes in the medical record.

Summary Of Background Data: Population-based studies of spine surgery have often relied on administrative databases as a primary information source, but little is known about the validity of using ICD9-CM codes to identify these operations.