Kayvan Haddadan, MD

Dr. Kayvan Haddadan is the President and Medical Director of Advanced Pain Diagnostic & Solutions, located in California. Dr. Haddadan founded the practice in 2012 and has served as its pain management physician for the past eight years. He works to ensure that each member of the group’s multi-disciplinary clinical team is focused on diagnosing and confirming the source of each patient’s pain, and then carefully developing and documenting the most effective treatment plans.

Dr. Kayvan Haddadan earned his Bachelor of Science degree from the College of Alborz in Tehran, Iran, and his Medical Doctor degree at Shahid Beheshti University of Medical Sciences. Afterward, he went on to receive his Educational Commission for Foreign Medical Graduates (ECFMG) Certificate in Philadelphia before undergoing an internship in Medical Surgery at Loyola University Medical Center’s Stritch School of Medicine in Illinois. Once he’d completed his internship Kayvan decided to fulfill his residency at Stritch School of Medicine in Physical Medicine & Rehabilitation.

Following his time in Illinois, Kayvan went on to complete his Fellowship in Pain Medicine at California Pacific Medical Center’s Pacific Pain Treatment Center while also training in Medical Acupuncture for Physicians from the University of California, Los Angeles, David Geffen School of Medicine. To say that Dr. Kayvan Haddadan is driven and hard-working would be an understatement. Throughout his career as a healthcare professional and a researcher, Dr. Haddadan has been published in 29 different research papers and projects. His research includes studies in gastroenterology, pulmonology, infectious disease, pain management, endocrinology, and cardiology.

Asha Byrd, MPAS, PA-C

Asha is a graduate of Rocky Mountain University of Health Professions in Provo, UT, and earned a Masters Degree in Physician Assistant Studies. She grew up in Davis, California and then attended Scripps College in southern California for her undergraduate education. She is a Shawnee Tribal citizen, and she participated in the Four Directions Summer Research Program at Harvard Medical School for Native Americans committed to healthcare careers.

She has worked previously at UC Davis Medical Center Emergency Department in Sacramento and also worked in senior living, geriatrics, and hospice care. She has also volunteered at the Sacramento Native American Health Clinic and Northeastern Tribal Health System in Oklahoma where she gained a deeper appreciation of the importance of providing holistic care to diverse communities.

Asha joined Advanced Pain Diagnostic and Solutions with the goal to provide compassionate and culturally competent care to our patients. In her spare time she enjoys reading, hiking, dancing, and takes pride in mentoring students interested in the PA profession.


Erik Smith, PA-C, MPH

The Associate Medical Director of Advanced Pain Diagnostic & Solutions, Erik Smith graduated with honors from Utah Valley University, and later from Brigham Young University, majoring in Exercise Science. He then received dual Masters Degrees in Physician Assistant Studies, as well as Public Health, at Touro University-California. He possesses several advanced certifications, which includes training in the field of Addiction Medicine.

He has worked in Emergency Medicine, Urgent Care, Family Practice, as a Sub-Investigator in Medical Clinical Trials, specialized in Amniotic Stem Cell Treatments, and has found his calling in Chronic Pain Management. He has trained and mentored many Medical Students, including the time when he was an Associate Professor of Family Medicine at California Northstate University-College of Medicine. Erik is bilingual with the ability to speak Spanish in addition to English.

Arian Behziz, DNP, FNP

Arian graduated from University of San Francisco with a Bachelor of Science in Nursing and a minor in Psychology and Gerontology. She then further continued her education in Loma Linda University and earned her Doctorate in Nursing Practice and became a Family Nurse Practitioner.

Arian is an empathetic Family Nurse Practitioner that has joined Advanced Pain Diagnostic & Solutions with a focus on providing quality care and having open communication with patients and their families. She brings with herself more than 8 years of clinical experience in Emergency Department as a Registered Nurse.


Jaqueline Parker, FNP

Jacqueline or Jackie, graduated from Samuel Merritt University’s Family Nurse Practioner Program with her Masters of Science in Nursing in 2018. She has over 30 years experience as a registered nurse in Medical -Surgical Nursing, Dialysis and has held multiple supervisory and management positions in the health insurance industry.

She started her NP career at Advanced Pain Diagnostics after interning with Dr, Haddadan as a student NP. Because of the experience she gained as a student, she had decided that helping patients that are suffering from chronic pain is one of the most compassionate ways to apply her experience and knowledge. Jackie loves making a difference at Advanced Pain Diagnostics & Solutions and believes her clinic makes an important difference in the lives of many.

Marisa Martin, MPA, PA-C

Marisa graduated from San Diego State University with a Bachelor of Science in Kinesiology Pre-Physical Therapy. She then furthered her education by earning a master’s degree in Physician Assistant Studies from Samuel Merritt University in Oakland, California.

Prior to PA school Marisa worked in Orthopedics and Neurosurgery clinics and worked as a lead clinical research coordinator. She also spent time as a clinical research associate performing quality control for multiple clinical trials in various medical specialties. She strives to find alternative options for her patients. She is an intelligent and a hardworking physician assistant that is admired by patients and her colleagues. In her spare time, she enjoys spending quality time with her husband and their two dogs going camping, hiking, and finding ways to stay active.  Marisa is a believer in teamwork and has joined Advanced Pain Diagnostic & Solutions to provide quality and compassionate care to our patients.


Rolando Santos, APRN, MSN, FNP

Rolando earned his Bachelor of Science in Nursing from the University of Santo Tomas, in Manila, Philippines in 2003, and his Master of Science in Nursing, Family Nurse Practitioner from Samuel Merritt University, in Sacramento California in 2016. He was awarded the Service Excellence achievement by DaVita and the Mercy Touch award by Mercy General Hospital (now Dignity Hospital).

Rolando Santos, Jr. is a Family Nurse Practitioner (FNP), certified in the state of California. He started his FNP career in 2016. Before becoming an FNP, he was an Acute Dialysis RN from 2010 to 2014 and has been an RN since 2003. His work has ranged from the Emergency Department, Medical-Surgical Department, Long Term Care facility RN, and Correctional RN.

Benjamin Pearce, MSN, APRN, FNP-BC

Ben graduated from Indiana University with a Bachelor of Science in Psychology in 2006. He then moved to Rochester, New York in 2010 to attend University of Rochester to earn his Bachelor of Science in Nursing. Ben completed his Master of Science in Nursing in Olivet Nazarene University in Bourbonnais, Illinois and became a certified Family Nurse Practitioner.

Ben started his nursing career at Clayton Residential Home as a Registered Nurse in 2011. He then went on to work in AMITA Saints Mary and Elizabeth Medical Center as a Registered Nurse Float and worked his way up to the Nurse Manager during his final years. Ben then moved to Sacramento California in 2020 and joined Dignity Health as a Float Pool Registered Nurse upon joining Advanced Pain Diagnostic and Solutions.