Except as provided in sections 48-138 and 48-139, there shall be no filing fees charged by the Nebraska Workers’ Compensation Court. When a reasonable attorney‘s fee is allowed the employee against the employer as provided in section 48-125, the compensation court shall further assess against the employer as costs of the employee the cost of depositions if admitted into evidence and may further assess against the employer the fees and mileage for necessary witnesses attending the proceedings at the instance of the employee. Both the necessity for the witness and the reasonableness of the fees shall be approved by the compensation court. Such witnesses shall be reimbursed for their necessary mileage at the rate provided in section 81-1176.