Dr. John P. Gruen is a neurosurgeon in Los Angeles, California and is affiliated with multiple hospitals in the area, including Keck Medical Center of USC and LAC+USC Medical Center. He received his medical degree from Columbia University Vagelos College of Physicians and Surgeons and has been in practice for more than 20 years. Dr. John P. Gruen accepts Aetna, Humana, Blue Cross, United Healthcare - see other insurance plans accepted.