Tel: 361.387.0046
Fax: 361.271.4147
McAllen Location
3001 N. 23 St.
McAllen, TX 78501
Tel: 956-627-3600
Fax: 956-322-5559
Patient Care with Integrity and Compassion
Providers
Providing you with the best doctors for the best care

Eric Liu, MD
Interventional Pain Specialist
Anesthesiology and Pain Medicine
Dr. Li-Herng (Eric) Liu, M.D is an ACGME credited fellowship-trained interventional pain medicine specialist and anesthesiologist. He is board certified in Anesthesiology and Pain Medicine. Dr. Liu is a member of the American Society of Anesthesiologists, International Spine Intervention Society, and the American Society of Interventional Pain Physicians...

Mitchell Engle, MD, PhD
Interventional Pain Specialist
Anesthesiology and Pain Medicine
In a world of assembly line medical care, Dr. Engle is markedly different; he is passionate about his patients and helping them achieve wellness. Since every patient comes with a unique life story, he places particular emphasis on knowing and evaluating the whole patient. As such, he firmly believes that each patient must be individually assessed and given a unique treatment plan. He and the The Institute of Precision Pain Medicine staff will all diligently work to identify and treat the causes of pain rather than just masking it with more pills.

Puneet Sayal, MD, MPH
Interventional Pain Specialist
Dr. Sayal's philosophy for patient care is simple - listen to his patient. Initially, this seemed like an obvious concept learned in medical school, but over time it has led him regularly to the right diagnosis and the ability to tailor his treatment plan to the needs of his patients. Personalizing care in the field of pain medicine is key to making the treatment meaningful to patients and improving their quality of life on their terms. Dr. Sayal is committed to understanding what is important to you, as a patient and an individual, and focusing his care on the aspects of life you want to see improve.
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Dr. David Cooper, MD
Interventional Pain Specialist
Physical Medicine and Rehabilitation
Dr. David Cooper, M.D. is an ACGME accredited fellowship-trained Interventional Pain Medicine and Physical Medicine and Rehabilitation specialist. He is board-certified in Physical Medicine and Rehabilitation and Pain Medicine and is a member of the American Academy of Physical Medicine and Rehabilitation and Texas Pain Society.
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Armando Garcia, MPAS, PA-C
Board Certified Physician Assistant
Mr. Garcia joined the Institute of Precision Pain Medicine in 2017 and has practiced medicine as a physician assistant for over 12 years. He is a native Corpus Christian who returned home shortly after completing his medical training to serve the community in which he grew up being a part of. He began his career caring for the indigent population of the Rio Grande Valley where he treated a multitude of complex cases. His experience includes Family Medicine, Internal Medicine, Geriatric Medicine, Occupational Medicine and Urgent Care.

Daniel Dat Nguyen, DO
Interventional Pain Specialist
Dr. Daniel Dat Nguyen is the newest ACGME accredited member of the Institute of Precision Pain Medicine team and main physician at our Baytown, TX location. He treats with a well-rounded philosophy which encompasses Osteopathic Medicine, Physical Medicine & Rehabilitation (PM&R), and interventional chronic pain management. Quality of life through improvement of the mind, body, and spirit is a core principle that guides the way he treats.

Debra Williams, MSN, APRN, FNP-C
Board Certified Family Nurse Practitioner
Debra Williams recently joined the Institute of Precision Pain Medicine in April 2023. She graduated with an Associates Degree in Nursing in 2003 and worked as a Registered Nurse in our community for twenty years. She decided to further her education and earned a Bachelor of Science Degree in Nursing, from The University of Texas at Arlington in 2019. Upon graduating she decided she wanted to continue to expand her knowledge and earned a Master of Science - Family Nurse Practitioner Degree, from The University of Texas at Arlington in 2022. She is certified by the American Association of Nurse Practitioners Certification Board and a current member of American Association of Nurse Practitioners.
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Lissa Ruiz, PA-C
Board Certified Physician Assistant
Lissa Ruiz was born and raised in South Texas. Mrs. Ruiz earned her Bachelor of Science Degree, with a minor in Psychology, from Texas A&M University – Kingsville in 2006, graduating with Honors. Upon graduation, Mrs. Ruiz attended the University of Texas-Pan American, where she earned her Bachelor of Science in Physician Assistant Studies in 2009. She is also Board Certified by The National Commission on Certification of Physician Assistants (NCCPA).