TTUHSC School of Medicine at Amarillo
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Faculty Profiles

Amarillo Surgery Physicians


 Regional Chairman

 Dan A. Galvan, M.D., F.A.C.S.

Dan A. Galvan, M.D., F.A.C.S.

Associate Professor

Critical Care/Trauma

Dr. Dan Galvan returned to the Texas Tech University Health Sciences Center (TTUHSC) in September of 2012 as Associate Professor and Chairman of the Department of Surgery.

Dr. Galvan is a graduate of Texas A&M University and the University of Texas Medical Branch in Galveston.  His post-doctoral education included a General Surgery Residency at St. Joseph Hospital in Houston and a fellowship in Surgical Critical Care at the University of Pittsburgh Medical Center.  He was in private practice for several years in Texas prior to joining Texas Tech’s Department of Surgery at Amarillo from 2000 to 2005.  After completing a fellowship at University of Pittsburgh Medical Center in 2006, he joined the faculty at the Penn State Hershey Medical Center where he was an Assistant Professor in the division of Trauma, Acute Care and Critical Care Surgery until his return to Texas Tech.

Dr. Galvan is board certified by the American Board of Surgery with additional qualifications in Critical Care.  He is completing his Masters in Health Profession Education at the University of Illinois at Chicago.  He has served in many roles as an educator and has received numerous honors and awards in teaching.


Division of General and Acute Care (Trauma Critical Care)

Surgeons in the Division of General Surgery specialize in the management of patients and the performance of surgery on these patients for diseases and abnormalities of a wide variety of organs and body systems. These organs and systems include: internal abdominal organs - the esophagus, the stomach, the gall bladder, the spleen, the liver, the pancreas, the small and large intestines, and the adrenal glands; the structures of the neck to include the thyroid and parathyroid glands, the trachea, the esophagus and the salivary glands; all non cosmetic conditions of the breast; all varieties of hernias - inguinal, femoral, incisional, ventral and diaphragmatic. Our General Surgeons also perform limited vascular and non cardiac thoracic procedures, (specialized procedures in these sub-specialties are performed by the members of the respective Divisions). By virtue of additional training and extensive experience the General Surgeons in this Division provide specialized Trauma and Critical Care to surgical patients.


M. Haris Nazim, M.D., FACS, FACCWS, CWSP

M. Haris Nazim, MD, FACS, FACCWS, CWSP

Assistant Professor of Surgery

Trauma Medical Director, Northwest Texas Health Care System

M. Haris Nazim, MD is an American Board Certified Surgeon with added qualifications in Advanced Wound care, Hyperbaric Oxygen therapy, Burn and Reconstructive Surgery and is certified in Advanced Cardiac / Trauma and Burn Life Support. He was recruited by Texas Tech University Health Sciences Center in Amarillo as a Medical Educator and Clinician in Trauma and Acute Care Surgery in 2011.

As the Trauma Medical Director at North West Texas Healthcare System; he oversees the quality of the trauma Program.  This is accomplished through a collaborative relationship with the Trauma Services Department, Nursing Administration and the relevant Medical Staff. This program is amongst the top 10 percent in the country for quality of care according to National Trauma Databank standards. 

The success of the trauma program has led to Dr. Nazim to continue efforts towards building a burn program in the area which would be an asset to the community.  His other interests include elective general surgery, advanced wound care, acute care surgery and trauma / critical care.


Ariel P. Santos, M.D., MPH, FACS, FRCSC

Ariel P. Santos, MD, MPH, FACS, FRCSC

Dr. Ariel P. Santos, a Fellow of the American College of Surgeons, is an American board certified surgeon with added subspecialty qualifications in Trauma, Acute Care Surgery and Surgical Critical Care.

Dr. Santos is a graduate of The University of Santo Tomas in Manila, Philippines and earned his Master’s Degree in Public Health from the University of Louisville in Kentucky. His post-doctoral education included a Residency in General Surgery followed by a Fellowship in Surgical Critical Care at the University of Louisville Hospital. After graduation, he moved to Canada where he practiced surgery as a Clinical Fellow at University of Toronto in St. Michael’s Hospital and as a solo practitioner within the Labrador Grenfell Health System in Newfoundland and Labrador.

While in Canada, Dr. Santos became a certified specialist and fellow of the Royal College of Surgeons. He later on returned to the United States when he was recruited to join the Trauma division at Penn State University Medical Center as assistant professor. Dr. Santos was there for three years where he also held the position of Associate program director of Emergency General Surgery. He then transferred to Amarillo, Texas to be a part of the Texas Tech University Health Sciences Center in November 2015.

Dr. Santos has received numerous awards during his training years and clinical practice including the Henry Christian Award and Dean’s award for teaching. He has also published in peer review journals. He enjoys teaching and has interest in outcome based research. He is a member of numerous organizations including the American College of Surgeon, Eastern Association for the Surgery of Trauma (EAST), Canadian Association of General Surgeon, and Hiram Polk Surgical Society.

Dr. Santos lives in Amarillo, Texas with his wife who shares his love for nature and interest in culture, travel and sports..


D. Shane Harper, PA-C, MPAS, DFAAPA

D. Shane Harper, PA-C, MPAS, DFAAPA

Harper returns to the Texas Panhandle by joining the Texas Tech Department of Surgery in July 2014. A native Texan, Mr. Harper grew up in Abilene and remained in Texas for his undergraduate education. After completing his undergraduate education he attended The University of Texas Medical Branch where he completed his Masters of Physician Assistant Studies with Honors.

Mr. Harper then practiced privately in Canadian, Texas for five years before leaving to attend a Critical Care Residency at the University of Massachusetts Medical Center. During his time at UMass, he served as chief PA resident with a professional emphasis on trauma and surgical critical care. After his residency, 

Mr. Harper relocated to Tulsa, Oklahoma for five years to serve as the lead PA for the Saint Francis Hospital Trauma/Acute Care Surgery Service in Tulsa, Oklahoma. After being recruited to join the Texas Tech Department of Surgery, he happily returned to Texas to be closer to family and friends.

Mr. Harper continues to care for the critically ill within the surigcal trauma intensive care unit daily along with treating trauma and acutely injured patients.

Mr. Harper's professional interest include emergency trauma procedures, critical care bedside procedures and educating students within a wide array of medical disciplines.

Outside of the hospital, Mr. Harper enjoys spending time with his wife and children, preferably on their ranch in Roberts County. .


John P. Schnatz, FNP-C, CCRN, MSN

John P. Schnatz, FNP-C, CCRN, MSN

Surgery Faculty Associate

John Schnatz, FNP-C joined as Faculty Associate in the Department of Surgery in 2011. He graduated from the College of St. Mary's, in Omaha, Nebraska with his undergraduate degree. He attended West Texas A&M University in Canyon, Texas, where he received his BSN and MSN degrees. He continued his training in Taos, New Mexico where he received his certification in First Assist in Surgery.

Mr. Schnatz also received his critical care registered nurse certificate in 1984. In his spare time he spends time with his wife and two children. He also enjoys participating in triathlons and completed his first Ironman competition in 2012.



Division of Surgical Oncology

By virtue of their advanced and specialized training beyond General Surgery, surgeons in the Division of Surgical Oncology provide diagnosis and surgical management of patients with initial, complex, recurrent or advanced malignant disease. The performance of surgery on these patients encompasses the entire spectrum of organs and body systems, to include the head and neck, thorax, abdomen, skin and skin structure, and all soft issue to include the breast. The management of malignant disease of the neurological system (brain, spinal cord and peripheral nerves) and the eye is excluded from the purview of these surgeons. Although certified in General Surgery, these Oncologic Surgeons do not as a routine perform elective General Surgery procedures.


Subhasis Misra, M.D., MS, FACCWS, FACS

Subhasis Misra, MD, MS, FACCWS, FACS

Associate Professor

Chief, Gastrointestinal and Hepato-Pancreato-Biliary Surgery

Subhasis Misra, MD is board certified by the American Board of Surgery and is also a Fellow of the American College of Certified Wound Specialists.  He brings with him significant expertise in providing comprehensive cancer care.   

Dr. Misra performs advanced surgery for cancers of the liver, pancreas, esophagus, stomach, and colon, including hyperthermic intraperitoneal chemotherapy and robotic procedures, as well as surgery for other diseases of the gastrointestinal tract. Additionally he performs complex surgical procedures to treat breast cancer, sarcoma, melanoma, and endocrine tumors. 

Dr. Misra earned his medical degree in India. He completed a general surgery internship at Rush University Medical Center in Chicago, Illinois, and a general surgery residency at Fairview Hospital/Cleveland Clinic in Cleveland, Ohio where he served as the Chief Resident.  

Dr. Misra then completed a surgical oncology fellowship at the University of Miami/ Jackson Memorial Hospital in Miami, Florida. He additionally holds a master’s degree in health systems management from Rush University in Chicago.  

Dr. Misra has been published extensively in peer reviewed journals and has also presented at numerous clinical conferences.   He enjoys a busy life with his wife and their beautiful little girl. During his spare time,

Dr. Misra enjoys reading and sports, and has a passion for quality improvement, leadership and understanding human behavior.


H. Nail Aydin, M.D., FACS, FACCWS

H. Nail Aydin, MD, FACS, FACCWS

Dr. Aydin obtained his medical degree from Istanbul University Cerrahpasa School of Medicine, English Division, Istanbul, Turkey. He did his surgical internship at Zurich University, Zurich, Switzerland.

After he completed five years of general surgery residency training at Haseki State Hospital in Istanbul, Turkey, he moved to the United States. He completed 2 years of a Clinical Research Fellowship in the department of Colorectal Surgery at the Cleveland Clinic.

He decided to complete an ACGME approved Residency training in Surgery and did his Internship in Surgery at the Cleveland Clinic, Cleveland, Ohio. He continued his training in Surgery at Yale New Haven Hospital and Fairview Hospital Cleveland Clinic Health System where he served as the chief resident in Surgery. After completion of his residency training in Surgery, Dr. Aydin completed a fellowship council approved fellowship training in Minimally Invasive Surgery and Advanced GI Endoscopy at St. Vincent Hospital, Indianapolis, Indiana.  

After his training, he served as a general surgeon for three years in West Plains, Missouri. After his service in the underserved area in Missouri, he completed a two year clinical fellowship training in Surgical Oncology at Mercy Medical Center affiliated with University of Maryland in Baltimore, Maryland.

After completion of his training in Surgical Oncology, he joined the department of Surgery at Texas Tech Health Sciences Center in Amarillo as a full time faculty in August of 2015.  He is a board certified surgeon by the American Board of Surgery. He is a fellow of American College of Surgeons.

Dr. Aydin is also certified in Wound Care by the American Board of Wound medicine and Surgery. He is also a fellow of the College of Clinical Wound Specialists. 

Dr. Aydin performs Complex Abdominal Surgery and treats Skin and Soft tissue tumors, Sarcoma, Breast Cancer, Melanoma, Complex GI Surgery, Pancreas and Hepatobiliary Surgery, Endocrine Surgery, and Peritoneal Surface Malignancies. He works closely with all cancer care providers in the panhandle area and participates in all aspects of multidisciplinary Cancer Care.


Division of minimally invasive surgery


Nathan Hansen, M.D.

Nathan Hansen, M.D. - Assistant Professor

Assistant Professor

Nathan Hansen, MD is board certified by the American Board of Surgery and completed additional fellowship training in minimally invasive surgery.  He joined Texas Tech University Health Sciences Center in Amarillo Department of Surgery in 2014.  His practice includes general surgery with a focus on advanced laparoscopic and robotic surgery.

Dr. Hansen graduated from Penn State College of Medicine and completed his general surgery residency training at The Penn State Milton S. Hershey Medical Center.  After finishing residency he completed a minimally invasive surgery fellowship through the Palo Alto, VA Healthcare System (Stanford Affiliate). 


LaJohn Quigley, M.D.

LaJohn Quigley, M.D.

Assistant Professor

LaJohn Quigley, M.D. is board certified by the American Board of Surgery in General Surgery and also Fellowship trained Minimally Invasive and Bariatric Surgery. Upon completion of a Bachelor of Arts Degree from the University of Texas, he returned to his home town of Lubbock, Texas to attend medical school at Texas Tech University Health Sciences Center.

Post-Doctoral education includes a General Surgery Residency at University Medical Center/Texas Tech University Health Sciences Center in Lubbock, Texas and a Fellowship in Minimally Invasive and Bariatric Surgery at Greenville Health Systems in Greenville, South Carolina.

Dr. Quigley joined Texas Tech University Health Sciences Center Department of Surgery as an Assistant Professor in September 2014. His practice includes Bariatric and General Surgery with a focus on advanced Laparoscopic and Robotic surgery.

Dr. Quigley enjoys spending time with his new wife and son, and traveling to Lubbock to visit family.



Darren Peterson, M.D., FACS

Darren Peterson, M.D., FACS, Associate Professor

Associate Professor

Dr. Darren Peterson is an alumni of both the Texas Tech Department of Mechanical Engineering and the School of Medicine.  After the collapse of the defense industry in the early 1990’s he left the engineering world and returned to Texas Tech to complete a minor in Biology and Chemistry before starting medical school in 1997.  His post-doctoral education continued at the University of Florida at Jacksonville where he developed a passion for Minimally Invasive Surgery. 

Following residency he entered private practice in Palm Coast, Florida where his interests expanded to include robotic surgery until his return to Texas Tech as an Associate Professor to join his long-time friend, Dr. Galvan to help rebuild and expand the Department of Surgery. 

His area of interest focuses on minimally invasive foregut and colorectal surgery.  Dr. Peterson is board certified by the American Board of Surgery and a  Fellow of the American College of Surgeons.


Division of General Surgery


Dr. Laith Al-Balbissi, M.D.

Dr. Laith Al-Balbissi, M.D.

Dr. Al-Balbissi received his Bachelor of Medicine and Bachelor of surgery degree from the University of Jordan.  He then joined East Tennessee State University where he had finished his surgical training.  

During his training, he received several awards for best teaching resident.  In 2015, he was awarded the “Eric R Manahan award for outstanding surgical resident performance”. Continuing his academic passion, he then joined the Surgery Department at Texas Tech University Health Science Center in Amarillo in 2015.  


Iza Obokhare, M.D., FACS, FICS

Iza Obokhare, M.D., FACS, FICS, Assistant Professor

Assistant Professor 

Dr. Izi Obokhare is a board certified general surgeon with additional qualifications in Colorectal Surgery, advanced laparoscopic and endoscopic surgery in Amarillo Texas. He received his medical degree from Howard University College of Medicine in Washington, D.C., and completed a general surgery residency at the University Hospitals of Cleveland – Case Western Reserve University in Cleveland OH.  He completed a fellowship in Colon and Rectal Surgery Research at the Ochsner clinic in New Orleans where he obtained additional training in the diagnosis and treatment of benign and malignant diseases of colon, rectum, and anus.

He has a special interest in state-of-the-art minimally invasive techniques and approaches to anorectal tumors such as transanal minimally invasive surgery (TAMIS), laparoscopic colectomy for colon cancer, familial colon cancer syndromes, diverticulitis, colonic inertia and ulcerative colitis.

Dr. Obokhare is a Fellow of the American College of Surgeons and a member of the American Society of Colon and Rectal Surgery, and the Society of American Gastrointestinal and Endoscopic Surgeons. In addition to the numerous leadership, academic and scholarship awards he has received,

Dr. Obokhare has presented his research at several scientific meetings. His research manuscripts have been published in peer reviewed medical journals. He lives in Texas with his wife Dr. Joy Obokhare an ENT and Facial Plastics surgeon and his two lovely children. He is currently accepting new patients with most insurance plans.


Alan Sbar, M.D. 

Alan Sbar, M.D. Associate Professor

Associate Professor

Dr. Sbar received his BA in Biochemistry from Rutgers in 1992. He graduated medical school from George Washington University in 1996. He was a General Surgery Resident at Brooke Army Medical Center. He worked overseas in Germany for 4 years and practiced in Wisconsin before joining the Texas Tech Family in 2014.  

He has two children and is married to Dr Evelyn Sbar who is the Clinic Director of Family Medicine.


Robert Gutierrez, FNP

Robert Gutierrez, FNP Faculty Associate

Faculty Associate

Robert joined the TTUHSC family in 2014. He graduated from WTAMU in May of 2013 with a BSN/MSN-FNP. He has practiced in Amarillo for 18 years.


Kendra Williams, FNP

Kendra Williams, FNP Faculty Associate

Faculty Associate

Kendra graduated from WTAMU in 2014 with a Master’s of Science and Nursing, Family Nurse Practitioner. She joined the Texas Tech Family in 2015. Before joining Texas Tech, she was an air ambulance flight nurse.



Division of Otolaryngology

Otolaryngologists provide comprehensive medical and surgical care to patients with diseases and disorders that affect the ears, the respiratory and upper alimentary systems and related structures of the head and neck. The care rendered by this Division is focused primarily on children who present with these conditions. A limited number of adults are accommodated by our current single specialist.


William P. Hale, M.D., F.A.C.S.

William P. Hale, M.D., F.A.C.S.

Clinical Professor of Surgery

William P. Hale, M.D. joined Texas Tech in 1977 as Assistant Clinical Professor while still in private practice.  He graduated from the University Of Louisville School Of Medicine, Louisville, Kentucky in 1958.  

Dr Hale was the first to finish Otolaryngology at Parkland Hospital in Dallas 1962.  He came to Amarillo following his residency to open a private practice; later when he retired from private practice he joined Texas Tech as Professor in 2001.  Dr Hale is board certified with the American Board of Otolaryngology.  

Dr Hale enjoys mentoring medical students and residents.  Outside of the office Dr. Hale appreciates photography, travel, and history.