Jeffrey A. Singer, M.D., F.A.C.S.

Board Certified General Surgeon

Founder of Valley Surgical Clinics. Dr. Singer received his M.D. from New York Medial College in New York City, where he was elected into Alpha Omega Alpha (Iona Chapter), the Honor Medical Society. He completed his Surgical Residency at Maricopa County General Hospital, Phoenix, Arizona. He is Board Certified in the specialty of General Surgery. He has over 20 years of experience in his field of general and laparoscopic surgery. Dr. Singer is a Fellow of the American College of Surgeons, the International College of Surgeons, the Southwestern Surgical Congress, & the American Society of Abdominal Surgeons.

Francisco Rodriguez, M.D., F.A.C.S.

Board Certified General Surgeon​

Received his M.D. from the Catholic University in Santiago, Dominican Republic. Dr. Rodriguez completed his Internship in General Surgery at Indiana University and Purdue University Hospitals in Indianapolis, Indiana. He completed a General Surgery Residency at the University of Illinois at Chicago, Cook County Hospital, after which he went on to a fellowship in Transplant Surgery at Ohio State University School of Medicine in Columbus, Ohio.

His experience in transplant surgery has given him a special expertise and interest in major pancreatic and liver surgery, in which he has earned a local reputation for excellence. He has become a Phoenix-area leader in the performance of laparoscopic Nissen fundoplication for severe gastro-esophageal reflux disease.

Continually striving to provide superior patient care along with advantages of the latest technology, Dr. Rodriguez and partners began training in 2008 in Robotic assisted surgery.

As one of the founding members of the Clinical Robotic Surgery Association, Dr. Rodriguez and his partners are paving the way in Robotic assisted surgery with new innovations and refinement of techniques. As a group they have successfully performed over 300 Robotic Surgeries to date.

In 2009, Valley Surgical Clinics had the pleasure of hosting to the first ever Robotics Symposium in Phoenix. Dr. Rodriguez was a featured key-note speaker on Robotics in Private Practice at this event.

Dr. Rodriguez is among a small group surgeons in the United States to perform daVinci® Robotic Thyroid and Parathyroid Surgery. He and his partners are quickly building one of Arizona’s largest Robotics programs using this new procedure. His early experience allows him to train other local surgeons, and develop training programs at local hospitals.

Dr. Rodriguez is Board Certified in the specialty of General Surgery. He is a C.A. Professor of Surgery University of Illinois, Chicago. Dr Rodriguez is a Fellow of the American College of Surgeon, the International College of Surgeons, and the southwestern Surgical Congress. Dr Rodriguez is fluent in Spanish.

Luis Hashimoto, M.D., F.A.C.S.

Board Certified General Surgeon​ ​

Dr. Hashimoto received his MD from San Marcos National University School of Medicine in Lima, Peru. Dr. Hashimoto’s post-graduate training was done at the Cleveland Clinic in Cleveland, Ohio where he received the Resident Achievement Award presented by the Society of Laparoendoscopic Surgeons. He studied abroad at Tohoku University in Sendai City, Japan where he received his PhD (Doctor in Medical Science). At Tohoku University he also received additional training on hepatobiliary and gastric cancer surgery, abdominal ultrasound, and was a member of the Liver Research Group.

Roozbeh Rassadi, M.D., F.A.C.S.

Board Certified General Surgeon​

Dr. Rassadi comes to Valley Surgical from Methodist Dallas Medical Center. He went to McGill University in Montreal, Canada where he obtained his masters in Physiology. He completed his residency in General Surgery at Drexel University College of Medicine in Philadelphia, Pennsylvania. He received the Golden Stethoscope nominee for excellence in teaching as a resident. Dr Rassadi then completed his fellowship in Upper GI/Hepatobilliary Surgery at Methodist Dallas Medical Center. Dr. Rassadi is a Candidate Member of the American College of Surgeons. Dr. Rassadi was a member of the Editorial Board for the McGill Journal of Medicine.

Scott Hillmann, M.D., F.A.C.S.

Board Certified General & Vascular Surgeon

A board certified general surgeon, Dr. Hillmann earned a bachelor’s degree in biology at the University of Delaware and a medical doctorate at George Washington University. After completing a surgical internship and general surgery residency at Rhode Island Hospital, he moved to Phoenix for a vascular surgery fellowship at Good Samaritan Hospital.

He has practiced in the Valley since 1982 focusing on all aspects of general and vascular surgery, performing his own angiograms and angioplasties as well as endoluminal aortic aneurysm repairs.

Mytia McNeal, M.D., F.A.C.S.

Board Certified General Surgeon

After earning a Bachelor’s degree at Michigan State University in Lansing, Dr. McNeal graduated from the Wayne State University School of Medicine in Detroit, Mich. She then completed both her internship and residency at the Loyola University Medical Center in Maywood, Ill.


With special interests in wound care and breast surgery, Dr. McNeal has received several honors and is active in a number of professional organizations. She is board certified in general surgery.

Christi Bourne, M.D., F.A.C.S.

Board Certified General Surgeon

Christi Bourne, MD, FACS, received her MD from University of California, Davis, and then completed her general surgery residency at Boston University Hospital. She graduated magna cum laude from UCLA/University of London with a BA in English literature, and is a member of Phi Beta Kappa. In 1990,  she began her practice in breast and general surgery with Valley Surgical Clinics, leaving in 1995 to establish the Valley's first breast only practice. In 2014, she rejoined VSC, and continues to treat breast cancer and related conditions exclusively.

She is a member of the American Society of Breast Surgeons, a board certified Fellow of the American College of Surgeons, and an active member of the Breast Program Leadership Committee at HonorHealth.
In addition to raising her own two children, she has volunteered for Big Sisters, Maricopa County Crisis Nursery, and most recently, as a foster parent providing respite care through AASK (Aid to Adoption for Special Kids). 

Mohan Ramalingam, M.D.

Board Certified General Surgeon

Dr. Ramalingam graduated from the National University of Singapore, Faculty of Medicine, in 2004. He became a Member of the Royal College of Surgeons (Edinburgh) in 2008 and obtained his Master of Medicine degree in Surgery from the National University of Singapore in 2009.

From 2010 to 2015, Dr. Ramalingam completed his General Surgery training at Phoenix Integrated Surgical Residency and obtained American Board of Surgery Certification.


He received additional sub-specialty training at the University of Miami in Laparo-endoscopic and Bariatric Surgery. He is a member of the American College of Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons.

Kristopher Johnson, M.D.

Board Certified General Surgeon

Dr. Johnson graduated summa cum laude from California Lutheran University with a Bachelors of Science in Biology.  He completed Medical School at the University of Arizona and completed General Surgery Residency at Phoenix Integrated Surgical Residency.  Dr. Johnson is Board Certified by the American Board of Surgery.

Joy Marvin, M.D., M.P.A., F.A.C.S.

Board Certified General Surgeon

Dr. Marvin is a board-certified general surgeon with >20years experience in private practice.  She has a Master of Public Health degree from the University of IL Chicago in Epidemiology and Biostatistics.  She graduated from Chicago Medical School in 1989 and went on to complete her general surgery internship and residency at the University of IL program in Chicago in 1994 which also included Cook County Hospital in its system at that time.  She initially practiced in Joliet, IL as a general surgeon for 11 years.  She married a Wisconsin native, however, and moved to Milwaukee for 10+ years.  She had a thriving practice there which included a busy practice in gastrointestinal surgery including gallbladder procedures, colon surgery for cancer and benign disease, laparoscopic procedures and other abdominal surgeries such as hernias and appendectomies and many colonoscopies.  She was the only surgeon at her hospital performing breast surgery and so was rather busy caring for both benign and malignant conditions of the breast.  She was active on a Milwaukee-wide committee responsible for making policy and recommendations for treating breast disease.  She has been an active member of the Society of Breast Surgeons.


Seeking respite from the cold snowy winters, Dr. Marvin and her husband have recently relocated to sunny Arizona.  Although a newcomer to Valley Surgical Clinics, she is an experienced general surgeon.  She seeks to ensure you have the best quality experience possible.  Being the only person in the medical field in her family, she makes it a point to talk to patients on their level in a “language” they can understand.  You will find her friendly, accessible, and willing to answer whatever questions you may have.

Varun Chakravorty, M.D.

Board Certified General Surgeon

Dr. Chakravorty completed his undergraduate studies at the University of Western Ontario.  After completing medical school at St. George University School of Medicine in Grenada, West Indies, he completed his general surgery residency at Saint Barnabas Medical Center. 

Erin Kloos, M.D.

Board Eligible General Surgeon

Dr. Kloos graduated from the University of Washington with a Bachelor’s of Science in Biology.  She completed Medical School at the University of Arizona College of Medicine and completed General Surgery Residency at the University of Arizona College of Medicine - Phoenix Integrated Surgical Residency & Banner University Medical Center.  Dr. Kloos is Board Eligible by the American Board of Surgery.

Chester Hayes III, M.S., PA-C

Certified Physician Assistant

Mr. Hayes, our Certified Physician’s Assistant, earned his undergraduate degree from Grand Canyon University in 1994. He completed post-graduate studies at Arizona School of Health Sciences in Phoenix, Arizona to become a Physician’s Assistant in 2003. Mr. Hayes has been working with Valley Surgical Clinics, LTD., since 2006. Mr. Hayes is an active member of the American Academy Of Physician Assistants, Arizona State Academy of Physician Assistants and is the Director of Zeta 21, the Hayes International Leadership Scholarship Foundation. When Mr. Hayes is not is surgery assisting our surgeons, he can be found on the Thunderbird high school basketball court, coaching the boys’ varsity basketball team.

Cynthia J. Shively, M.S.N., FNP-BC, CNOR, RNFA

Nurse Practitioner

Ms. Shively received her Bachelor’s of Science degree in Nursing from Chamberlain College of Nursing in St. Louis, MO. She obtained her First Assistant certification from Perioperative Associates at Gateway College in 2004. She went on to become Certified Nurse of the Operating Room in 2004. Cynthia completed her Master degree in Nursing with her Family Nurse Practitioner degree from St. Louis College of Nursing. Ms. Shively is an Active member of the Association of Operating Room Nurses, the National Association Orthopedic Nurses, active member of the American Academy and the American College of Nurse Practitioners. Her collaboration with the Arizona Dominican Medical Friends, a non-profit surgical group, provides free surgical care to the indigent of the Dominican Republic and works to promote a mentorship program to the operating room nurses in the Dominican Republic.

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