Section 13-J - Medical or surgical treatment by insurance carriers and employers(1) An insurance carrier shall not participate in the treatment of injured workers, except as provided in paragraph five of subdivision (i) of section thirteen of this article and subdivision seven of section thirteen-a of this article and except, that it may employ medical inspectors to examine compensation cases periodically, while under treatment, and report upon the adequacy of medical care, and other matters relative to the medical conduct of the case, a copy of which report shall be filed directly with the chair within ten days, and that it may maintain rehabilitation bureaus operated by qualified physicians if authorized by the chair in accordance with section thirteen-c of this article. (2) An employer may maintain a compensation medical bureau at the place or places of employment, if such bureau is required because of the nature of the industrial hazards, or the frequency of injuries to employees arising out of industry. Such bureau or bureaus shall be authorized and licensed pursuant to section thirteen-c, and their use by an injured employee shall be optional in accordance with the provisions of section thirteen-a.N.Y. Work. Comp. Law § 13-J