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David J. Sandercock, D.O.

Dr. David Sandercock has been a physician with NSAHA since 1996. He is board certified in Family Practice. He completed medical school at the University of Osteopathic Medicine in Des Moines, Iowa and his internship at the University of Texas at Houston. He enjoys family practice because of its daily variety and the long term relationships that develop with patients. He also enjoys encouraging preventive care and a holistic approach to patient care. He and his wife Sharon have three daughters.

David J. Sandercock, D.O.


Walter Walthall, IV, M.D.

Dr. Walter Walthall has been a physician with North San Antonio Healthcare Associates since 2002. He is board certified in Family Practice. Dr. Walthall was born and raised in San Antonio, he received his medical degree from the University of Texas Medical School in Houston. Dr. Walthall believes in providing comprehensive medical care with emphasis on patient education and family values.

Walter Walthall, IV, M.D.

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Dr. Clifford Alprin was born in Tulsa, Oklahoma and raised in Houston, Texas. He attended college at Baylor University in Waco and then Medical School at the University of Texas Health Science Center San Antonio. He completed his internship and residency in Family Medicine at the University of Oklahoma – Tulsa where he served as chief resident. He is married to his lovely wife, a pediatrician, Dr. Hawkins-Alprin and they have one son. Dr. Alprin believes in a patient first approach with an emphasis on preventative medicine.

Clifford N. Alprin, M.D.

Sarah C. Brown, PA-C

Sarah Brown is a NCCPA certified Physician Assistant (PA-C). She completed her master’s of Physician Assistant studies from UT Health Science Center in San Antonio where she was inducted into Pi Alpha, the National PA Honor Society. She completed her undergraduate degree from UW-Madison and is a proud badger. Sarah moved to Texas in 2007 working with the national program Teach For America. She enjoys working collaboratively with the physicians in the clinic to provide comprehensive, holistic care to all patients.

Sarah C. Brown, PA-C

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Paulla Churchwell is a NCCPA certified Physician Assistant (PA-C). She obtained both her masters of Physician Assistant Studies and Bachelor of Science in Respiratory Therapy from UT Health Science Center in San Antonio. She has a background in research and has published articles in JAMA and CHEST. She is a native Texan with three beautiful daughters. She enjoys spending time outdoors in the Texas Hill Country with family and friends. She loves working in Family Practice and takes great pride in the relationships she has built with her patients based on trust, compassion and quality healthcare.

Paulla Churchwell, PA-C


Tami (Rocha) Wieland is a certified Physician Assistant (PA-C).  She graduated from UT Health Science Center in San Antonio in 2008 and has worked in Family Practice and Emergency Medicine in La Vernia and San Antonio.  Tami has lived in the La Vernia area for the past 20 years.  Her passion is to help patients and families with their medical needs and to be an asset to the La Vernia community.

Tami (Rocha) Wieland, PA-C

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Russell Taylor Ross is an AANP board certified Family Nurse Practitioner (FNP-C). He obtained his Masters of Nursing in Family Practice at the University of Texas at Arlington. Russell started his medical career as a medic in the US Army in 1989 where he later became a nurse. As a nurse in both the Army and various local hospitals he has enjoyed the experience of working with diverse populations with varying medical needs. He has a passion for helping his patients reach their health care goals through a holistic and preventive approach. A father of four, Russell comes from a family of nurses. Three of his sisters, his oldest son and oldest daughter are all nurses. He is driven by the love of serving others, and finds his strength in God and his ever-supportive wife who is also an RN in the San Antonio area.

Russell T. Ross FNP-C

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Marlene Herrera is an AANP board certified Family Nurse Practitioner (FNP-C). She graduated from the University of Texas at Arlington with a Master’s of Science in Nursing. Marlene has been a nurse for over 10 years, majority of which were spent in the emergency department. She was born and raised in Floresville, Texas and is excited to be able to serve the patients of Wilson County. During her free time, Marlene loves to travel and enjoys spending time with her husband and their four children.

Marlene Herrera FNP-C

Gordon T. Hill, M.D.

Dr. Gordon Hill was taken to be with the Lord on Saturday, November 28, 2020.  He graduated from Texas A&M University in 1969 with a degree in zoology and obtained a medical degree from the University of Texas Health Science Center at San Antonio in 1975.  He started North San Antonio Healthcare Associates, in 1978 and was still practicing medicine at the time of his passing. Dr. Hill genuinely loved caring for his patients and was adored by generations of families that he cared for over his 42-year career.  His loving and generous spirit will be dearly missed by anyone whose life he touched.

In Loving Memory Gordon T. Hill, M.D.

Physicians: Testimonials
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