Background on California Workers’ Compensation and MPNs:  “In recent years, the California workers’ compensation system has seen significant increases in medical costs. Between 1997 and 2003, workers’ compensation medical treatment expenses in California increased by an estimated 138 percent, outpacing the costs for equivalent medical treatment provided in non-industrial settings. To abate this rise in costs, major reforms were made in 2003 and 2004. One such effort was the signing into law of Senate Bill (SB) 899 in April of 2004. One major component of SB 899 was the option for self-insured employers or insurers to establish a medical provider network (MPN), as promulgated in Labor Code Section 4616 et. seq. MPNs were implemented beginning January 1, 2005.  An MPN is a network of providers established by an insurer, self-insured employer, Joint Powers Authority (JPA), the State, a group of self-insured employers, a self-insurer security fund, or California Insurance Guarantee Association (CIGA) to treat work-related injuries. The establishment of an MPN gives significant medical control to employers. With the exception of employees who have a pre-designated physician, according to California Labor Code Section 4600, employers that have established an MPN to control the medical treatment of employees injured at work for the life of the claim as opposed to 30 days of medical control that employers had prior to SB 899. Having an MPN means the employer has more control with regard to who is in the network and who the injured worker sees for care for the life of the claim. The employer gets to choose who the injured worker goes to on the first visit: after the first visit, the injured worker can go to a doctor of his/her choosing in the MPN. Before the implementation of an MPN, insurers and employers are required to file an MPN application with the DWC for review and approval, pursuant to Title 8 CCR §9767.1”