TMC PULSE

t m c » p u l s e | o c t o b e r 2 0 1 6 20 Tinkering with the Future Health problem? A medical device might fix it. A lbert Huang, M.D., founder and CEO of Allotrope Medical, was a general surgery resident at Houston Methodist Hospital when he realized he had a great idea for a medical device. Huang often assisted on sigmoid colon resection, a surgery to remove part of the colon affected by conditions including diverticulitis—an inflamma- tion of the colon. "As I would work with the more senior surgeons, there would be certain aspects of the operation that were often time-consuming," said Huang, a member of the Texas Medical Center Innovation Institute's first TMCx accelerator medical device class. A critical step of a sigmoid colon resection is locating the ureter, a tube that carries urine from the kidney to the bladder, to make sure it is not harmed during surgery. Damage to the ureter is not uncommon and can lead to prob- lems including urine leaks (a hole in the ureter), abscesses (swollen areas where pus collects), a loss of kidney function or even death. "We did one resection where there was a lot of scarring, and we probably spent 30 percent of the time trying to identify the ureter before we could even start the surgery," Huang said. Surgeons typically do one of two things to locate the ureter before surgery: Have a urologist find it and place a stent in it, or search for it themselves via tissue dissection. While consider- ing different ways to simplify this process, Huang took inspiration from a method anesthesiologists use to make facial nerve muscles twitch via low-current electricity. He built a hand-held device that sends a short pulse of current down the tip of the device with the push of a button. The current causes the ureter to contract; that way, surgeons know where it is and can avoid harming it. Huang hopes the TMCx accelerator class will help him refine the device and capture the attention of doctors interested in trying it. Building prototypes Over the years, many Texas Medical Center doctors, researchers and per- sonnel have helped design or implant medical devices considered state-of- the-art for their time. In 1966, the late Michael E. DeBakey was the first to successfully implant a left ventricular assist device (LVAD), which pumps blood to the body after the heart has failed. DeBakey worked at Baylor College of Medicine, directed the Houston Methodist DeBakey Heart & Vascular Center and was senior attending surgeon at Houston Methodist Hospital. He and colleagues developed the DeBakey Ventricular Assist Device; DeBakey believed that B y C h r i s t i n e H a l l M E D I C A L D E V I C E S O F T H E T M C two of these working together could function as a total heart replacement. Denton Cooley, M.D., once DeBakey's protégé and then a cardiolo- gist with the Texas Heart Institute, was the first to implant a total artificial heart into a patient in 1969. If doctors DeBakey and Cooley are considered the James Bonds of medicine, Juan Fernandez would be the medical device equivalent of "Q." He was working in the machine shop at Baylor College of Medicine when asked to help DeBakey prototype an early version of the LVAD. The prototype was a small, plastic device that featured an impeller, a fan-like rotor operated by magnets. Today's versions have a titanium impeller. Now lead machinist at the Houston Methodist Machine Shop, Fernandez is proud to show off the prototype, which he keeps in the drawer of an old tool chest. Fernandez's father died of a heart attack when he was young. "I take pleasure in knowing that I have helped people, though I wish I could have helped my dad," he said. Denton A. Cooley, M.D., holding a BiVACOR total artificial heart. Credit: Terry Vine Photography CHI St. Luke's Health In 1996, Zvonimir Krajcer, M.D., repaired an abdominal aortic aneurysm by inserting a stent graft into the aneurysm through small incisions in the groin. To execute this new technique, Krajcer, now program director of peripheral vascular inter- ventions at the Texas Heart Institute and Baylor St. Luke's Medical Center, designed a tiny graft, 4.7 millimeters in diameter, to help seal off and repair the aneurysm. Memorial Hermann- Texas Medical Center The Kim-Dannenbaum-Shin Microsurgical Robotics Laboratory is developing robotic devices for procedures to treat cerebral stokes and other brain abnormalities. The devices can navigate small, narrow and branched blood vessels in the brain to reach sites deep in the body.

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