Doctors & Staff

The practice

At Advanced Surgical Associates our patients’ comfort and well-being are our priority. We take pride in utilizing modern, minimally-invasive techniques that effectively resolve a variety of health concerns, including gastrointestinal disorders, obesity, and diseases of the breast, with minimal downtime. Our experienced staff of compassionate and educated professionals is here to support you from your initial consultation through your recovery.

  • Quotes

    Everyone says [Dr. Thoman] is the best, and I agree.
    — Patient
  • Meet the surgeons

    Dr. David Thoman
    Specializes in minimally-invasive gastrointestinal and weight loss surgery.

    Dr. Kimberly Grafton
    Specializes in treatment of breast cancer and disease, and malignant melanoma.

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  • Dr. Mazen Hashisho
    Specializes in Vascular/Endovascular and Thoracic Surgery.

  • Mission Statement

    We're here to help you through this challenging time as you consider your options for a healthier lifestyle. Our goal is to provide sage and effective modern care in an environment of support and compassion. We strive to give you confidence in our techniques and comfort in our care.
  • Why choose us

    There are many reasons why people choose Dr. Thoman for their bariatric procedure. He offers impressive credentials, innovative techniques, and a proven record of safety. He is a highly trusted and respected bariatric surgeon in California who has been able to help thousands of people like you live better lives.