Robotic Surgeon at the Forefront of Medical Innovation

American U of Caribbean Dr Johnson Robotics

What is robotic surgery? To the uninitiated, it might conjure up images of everything from Star Wars’ beloved character R2-D2 to the Roomba automatic vacuum cleaner. But for Matthew Johnson, MD, it’s just a way of life.

Dr. Matthew Johnson, MD ’05 with the Da Vinci robotic surgery system.
As a board certified robotic surgeon, Dr. Johnson performs surgery using very small tools attached to a robotic arm, which he controls with a computer. The robot follows his hand movements to perform the procedure using the tiny instruments, and a 3-D camera allows him to view enlarged images of the patient’s body throughout the surgery.
The benefits? Tiny, robot-manipulated tools mean greater precision and smaller incisions than traditional open surgery. This results in a host of other positive outcomes: reduced blood loss, quicker healing time, decreased risk of infection, and shortened hospital stays.
“I do about 95 percent of my surgeries robotically now,” said Dr. Johnson, who began using the method about three years ago. “The instruments are so precise. It’s really a great thing.”
Starting a Career in Surgery
A Houston native, Dr. Johnson had wanted to be a physician since he was ve years old. His passion grew from playing doctor with his family to majoring in microbiology at the University of Texas at Austin. The culminating experience was after college, when he joined his father on a business trip to Holland. His father was a lawyer who worked with several Dutch cardiac surgeons, and Dr. Johnson had the opportunity to watch a nine-hour double aortic replacement surgery.

“Once I saw that, I just said, ‘wow, this is it,’” says Dr. Johnson.
Now, more than ever, he knew that surgery was the career for him. But he had a critical obstacle—he wasn’t accepted into the U.S. medical schools he’d applied to. He wasn’t a great test-taker, and his MCAT score didn’t fully reflect his abilities. So he chose to apply to a medical school that looked beyond the numbers: American University of the Caribbean School of Medicine.

“It was incredible,” said Dr. Johnson. “I miss it every single day. And I did my third-year clinical rotations in England—if I had gone to an American medical school, I wouldn’t have been afforded that opportunity. I was able to travel everywhere.”
After graduating from AUC, Dr. Johnson completed his surgery residency at University of Nevada School of Medicine in Las Vegas, where he served as chief resident and earned the Professionalism Award. He stayed at UN as a fellow in the acute care surgery program. UN was the first in the country to develop this fellowship, which combines a year of surgical critical care and a year of acute care surgery.
“It makes you prepared for anything surgical that comes in the hospital. You know you can take care of it,” said Dr. Johnson.

Getting a Patient Back in the Game 
Today, Dr. Johnson continues to work out of Las Vegas, where he is associated with several different hospitals. He specializes in gallbladder, hernia and foregut surgery, as well as trauma, general and acute care surgery.
“I can’t imagine myself doing anything else,” he said. “With surgery—especially trauma—you don’t know what’s coming. You know what the books have said and what your training has provided you, but it’s spontaneous. You see the patient and sometimes there’s blood coming out of every orifice and organ there is—you have to know what to do and how to take care of it. It’s fast and furious. You just have to stop the bleeding.”
One of his most memorable experiences was treating a 14-year-old boy with life-threatening injuries to his pancreas, small intestine and colon from a bad hit in a football game. The boy spent a month in the hospital. A year later, he’s made a full recovery and is back on the football field as an All-Star player.
He and Dr. Johnson still keep in contact—in fact, Dr. Johnson cheered him from the stands at a recent game.
“Patients like that really touch my heart,” said Dr. Johnson. “The patient and their whole family are so thankful. And for me, to know that my team and I have saved a life—it means so much.”
No matter the situation, Dr. Johnson prides himself on being a compassionate doctor.
“Spending that extra time and showing compassion often get lost in the workload. I do as much as I can to make sure that doesn’t happen,” said Dr. Johnson. “It’s worth spending that time. I just try to let them know I’m here and that they’re going to be okay.”


Congratulations! Matthew Johnson MD now FACS

What “FACS” Means
The American College of Surgeons is a scientific and educational association of surgeons that was founded in 1913 to improve the quality of care for the surgical patient by setting high standards for surgical education and practice. Members of the American College of Surgeons are referred to as “Fellows.”

Fellow, American College of Surgeons


The letters FACS (Fellow, American College of Surgeons) after a surgeon’s name mean that the surgeon’s education and training, professional qualifications, surgical competence, and ethical conduct have passed a rigorous evaluation, and have been found to be consistent with the high standards established and demanded by the College.
All Fellows are required to have the following qualifications:

Graduation from a medical school acceptable to the American College of Surgeons.
Certification by an American Surgical Specialty Board which is a member of the American Board of Medical Specialties and which is appropriate to the applicant’s specialty practice, or an appropriate specialty certification by the Royal College of Physicians and Surgeons of Canada.
A full and unrestricted license to practice medicine in their respective state or province.
One year of surgical practice after completion of all formal training. Additional practice time may be required if the practice situation and/or geographic location changes. Exceptions may be granted by the Fellowship Liaison Committee.
A current appointment on the surgical staff of the applicant’s primary hospital with no reportable action pending which could adversely affect staff privileges at that or any other health care facility.
A current practice that establishes the applicant as a specialist in surgery. The degree to which a practice must be restricted to the specialty is to be determined by a responsible College Credentials Committee. The limitation of an applicant’s practice to the scope of the designated specialty is an important consideration.
Interest in pursuing professional excellence both as an individual surgeon and a member of the surgical community. Such interest may be evidenced by membership in local, regional, and national surgical specialty societies; participation in teaching programs and on hospital committees; continuing medical education through attendance at professional meetings, courses, and seminars.
Ethical fitness as well as professional proficiency as determined by an appropriate College Credentials Committee. This determination is based upon information obtained from Fellows who were consulted as references and from other sources.

What Causes Abdominal Pain


Pain can arise from any of the structures within the abdomen or the abdominal wall. In addition, pain messages originating in the chest, back, or pelvis can sometimes be perceived as coming from the abdomen. For example, patients with heart attacks or pneumonia sometimes complain of upper abdominal pain rather than chest pain. There are many possible causes of pain. The table shows some of the more common causes of pain:

Non-abdominal causes:

Pneumonia (lung infection)
Myocardial infarction (heart attack)
Pleurisy (irritation of the lining around the lungs)
Pulmonary embolism (blood clots to the lungs)


Dr. Johnson did his undergraduate training at the University of Texas at Austin and is a faithful Texas Longhorn to this day. He subsequently attained his Medical Doctorate at the American University of the Caribbean, in St. Maarten, N.A. where he also attained a Masters in Medical Science (M.M.S.). Dr. Johnson’s residency training was completed at the University of Nevada School of Medicine, Las Vegas, NV in General Surgery (2005-11).

He then went on to become one of the early fellows in the country to complete an Acute Care Surgery fellowship at the University of Nevada School of Medicine, Las Vegas, NV (2011-13). During his residency and fellowship, Dr. Johnson also trained in Surgical Endoscopy with a specific emphasis on both diagnostic and therapeutic ERCP. In fact, along with other colleagues, he developed a new method for treating obstructing complicated biliary disease using combined cholecystectomy and ERCP in a one stage procedure, so-called the “One-Step/ELBS”. Throughout residency and fellowship, Dr. Johnson presented at many national conferences regarding ERCP use by surgeons for trauma and general surgery in addition to authoring several publications.

Following post-graduate training, Dr. Johnson joined Desert Surgical Associates and hit the ground running. He cares for patients in the field of general surgery, minimally invasive surgery, trauma, and critical care. Dr. Johnson’s specific interests involve minimally invasive robotic surgery, advancement of minimally invasive surgery in trauma patients, foregut surgery, hepatobiliary surgery and the use of ERCP for both diagnostic and therapeutic measures.

Care Philosophy

Dr. Matthew Johnson is a very compassionate surgeon that always takes extra time when communicating with his patients as well as their families regarding their care. He is driven, kind, and extremely innovative in the field of surgery. He is also one of the few surgical endoscopists in the country. In 2011, as a chief resident, he received the Professionalism Award at the University of Nevada School of Medicine and continues to emphasize this professionalism throughout his surgical practice. He is very well respected by his colleagues in the field and always strives for perfection.

Lessons Learned from the Las Vegas Mass Shooting Tragedy

ACS COT Trauma Panel

Trauma surgeons share lessons learned from the Las Vegas mass shooting tragedy
at American College of Surgeons conference.

The session highlighted real-world insights from Nevada trauma surgeons who
treated seriously injured patients as a result of the deadliest mass shooting
in modern U.S. history at an outdoor music festival in Las Vegas on October 1.

“In the 􀁾rst 24 hours, we saw 212 patients and performed 58 surgeries,” said Matthew Johnson, MD, FACS, with the Sunrise Hospital and Medical Center, Las Vegas. Sunrise staff grouped pods of operating rooms together for treating speci􀁾c types of cases. “More than 100 physicians and more than 200 nurses responded to assist for a total of 83 surgeries performed. Everyone did their jobs. As for the residents—we couldn’t have gotten through this [incident] without them,”Dr. Johnson said.



Appendicitis is inflammation of the appendix. It may be acute or chronic.

In the United States, appendicitis is the most common cause of abdominal pain resulting in surgery. About 5 percent of Americans will experience appendicitis at some point in their lives.

Appendicitis can happen at any time, but it occurs most often between the ages of 10 and 30. It’s more common in males than in females.

If left untreated, appendicitis may cause your appendix to burst and cause infection. This can be serious and sometimes fatal.

The classic symptoms of appendicitis include:

  • Dull pain near the navel or the upper abdomen that becomes sharp as it moves to the lower right abdomen. …
  • Loss of appetite.
  • Nausea and/or vomiting soon after abdominal pain begins.
  • Abdominal swelling.
  • Fever of 99-102 degrees Fahrenheit.
  • Inability to pass gas.
Treatment options for appendicitis:

Treatment for appendicitis varies. In most cases, however, surgery will be necessary. The type of surgery will depend on the details of your case.

Pancreatic Microbiome Influences Cancer and Its Treatment


From Medscape

It’s not only about the gut anymore. Even the pancreas has a microbiome, one that influences pancreatic cancer progression and that can be manipulated to resensitize the immune response in pancreatic adenocarcinoma.

A new study shows that pancreatic cancer harbors a 1000-fold higher concentration of bacteria compared with the normal pancreas. Moreover, the bacterial species in the pancreatic microbiome can shut down the immune response so that the pancreatic carcinoma milieu becomes ruled by immune suppression.

These observations were first made in animal models and were then extended to human patients with pancreatic ductal adenocarcinoma, which is typically fatal within 2 years.

In animal models, when the microbiome is ablated, the immune response is restored, and the animals are able to respond to immunotherapy.

One of the study’s corresponding authors, George Miller, MD, leader of the Tumor Immunology Program at NYU Langone Health’s Perlmutter Cancer Center, New York City, told Medscape Medical News: “Genetic mutations are not the sole components that explain pancreatic cancer progression, as mutations alone are insufficient for disease progression. One also needs an immune system that exhibits tolerance to the tumor.”

The study was published online March 22 in Cancer Discovery.

The Study

The researchers first showed that bacteria, when fed to mice, migrate from the gut to the pancreas, and that the microbiome of normal mice was distinct from that of mice with pancreatic cancer that expresses mutant KRAS, which is the commonly mutated gene in pancreatic cancer.

To characterize the human pancreatic microbiome, the researchers, using 16S rRNA gene sequencing, showed that the pancreatic microbiome in human patients was distinct from that of persons without pancreatic cancer. (Miller explained that normal pancreatic microbiome was determined from analyses of the pancreatic microbiomes of individuals who presented for surgery for benign endocrine tumors.)

To support the notion that the pancreatic microbiome promotes progression to pancreatic dysplasia, the researchers used two mouse models — a cohort expressing mutant KRAS, and a cohort that harbored mutant KRAS as well as mutant TP53.

Tumor progression was seen in both animal models, compared with control mice, but was quicker in the cohort with both mutations. However, for animals treated with an oral antibiotic, tumor burdens were reduced by ~50%. “These studies showed that the oral antibiotic regimen was able to slow pancreatic tumor growth,” Miller said.

The researchers also showed that longitudinal pertubations in the pancreatic and gut microbiome are associated with pancreatic dysplasia over time. They did this by serially profiling fecal bacteria in mice with pancreatic cancer and in control mice over 9 months. Although the bacterial community in the gut of mice with pancreatic cancer was similar in early life to that of wild-type mice, the gut microbiomes diverged over time, and after week 20, the microbiome of mice with pancreatic cancer was distinct from that of wild-type animals.

Extending these observations to humans, the researchers showed that Proteobacteria organisms composed ~8% of gut bacteria of pancreatic ductal adenocarcinoma patients but that they increased to 50% in cancerous pancreas. When the researchers obtained samples of both feces and tumors, they were able to show a differential migration of the bacteria to the pancreas. In progression toward the oncogenic phenotype, bacteria such as ProteobacteriaActinobacteria, and Fusobacteria spp predominate the pancreatic microbiome.

Immune Involvement Explained

But how does one show that these bacteria are responsible in some measure for promoting pancreatic oncogenesis? Toward this end, the researchers ablated gut bacteria from mice with pancreatic cancer using oral antibiotics and repopulated cohorts using feces derived either from wild-type mice or cancer-bearing mice. They found that bacterial ablation (with antibiotic) protected against disease progression. They also found that repopulating with feces from mice that had pancreatic cancer accelerated tumor growth, whereas repopulating with feces from wild-type animals did not.

Miller explained that when they analyzed the immune compartment of animals with pancreatic cancer, they were able to show that ablation resulted in an increase of intratumoral T cells and a reduction in myeloid-derived suppressor cells, suggesting a change in the tumor microenvironment from immune suppression to immune activation.

An analysis of tumor-associated macrophages also confirmed a change in the type of macrophages that were recruited to the pancreatic tumor microenvironment after bacterial ablation. T-cell and chemokine profiling confirmed changes in the tumor microenvironment to one in which the immune system was activated, not suppressed.

“While combinations of changes in genes like KRAS cause cells to grow abnormally and form pancreatic tumors, our study shows that bacteria change the immune environment around cancer cells to let them grow faster in some patients than others, despite their having the same genetics,” Miller said.

The bacterial species abundant in the pancreatic microbiome release membrane components such as lipopolysaccharides and proteins such as flagellin that shift macrophages — key immune cells in the pancreas — to increase immune suppression, the authors note.

Miller explained that their experiments pointed out that suppression occurs through toll-like receptors. Suppressor macrophages bind to by-products of bacteria, and the complex induces T-cell suppression, he said.

The animal model explains how the pancreatic microbiome may establish itself in patients. “Our bacterial translocation experiments suggest interactions between the two compartments [pancreas and intestines], presumably via the pancreatic duct which is in anatomic continuity with the intestinal tract,” the researchers write.

In addition, when ablated animals were tested for programmed death–1 (PD-1) expression, the expression of PD-1 tripled, and response to PD-1-based immunotherapy was observed. This allowed the researchers to determine how to extend their observations to patients with pancreatic adenocarcinoma.

Clinical Implications

“Our results have implications for understanding immune suppression in pancreatic cancer and its reversal in the clinic,” commented senior coauthor Deepak Saxena, PhD, associate professor of basic science and craniofacial biology at the New York University College of Dentistry, New York City.

“Studies already underway in our labs seek to confirm the bacterial species most able to shut down the immune reaction to cancer cells, setting the stage for new bacteria-based diagnostic tests, combinations of antibiotics and immunotherapies, and perhaps for probiotics that prevent cancer in high-risk patients,” he said in a statement.

Miller agreed. “Our study shows that the pancreatic microbiome can be a target for therapy and offers a clue about how to use immunotherapy in pancreatic cancer, which has thus far remained unresponsive to immunotherapy,” he told Medscape Medical News.

Miller noted that the team is in the process of fine-tuning a study protocol that will determine whether giving a combination of antibiotics such as ciprofloxacin and metronidazole to patients with resectable pancreatic adenocarcinoma will improve the efficacy of a PD-1 inhibitor. They plan to recruit about 30 patients into the study.

The authors have disclosed no relevant financial relationships.

Cancer Discov. Published online March 22, 2018. Abstract