California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4.5 - Division of Workers' Compensation
Subchapter 1 - Administrative Director-Administrative Rules
Article 5.3 - Official Medical Fee Schedule
Section 9789.18.6 - Anesthesia - Multiple Anesthesia Procedures

(a) Physicians and non-physician practitioners shall bill for the anesthesia services associated with multiple bilateral surgeries by reporting the anesthesia procedure with the highest base unit value with the multiple procedure modifier "-51." The total time for all procedures shall be reported in the line item with the highest base unit value.

(b) If the same anesthesia CPT code applies to two or more of the surgical procedures, billers enter the anesthesia code with the "-51" modifier and the number of surgeries to which the modified CPT code applies.

(c) Payment can be made under the fee schedule for anesthesia services associated with multiple surgical procedures or multiple bilateral procedures. The maximum fee is determined based on the base unit of the anesthesia procedure with the highest base unit value and time units based on the actual anesthesia time of the multiple procedures.