One surgery tackled the double trouble of nutcracker syndrome and superior mesenteric artery syndrome

UCHealth’s autotransplant clinic focuses on patients whose superior mesenteric arteries get in the way.
Feb. 3, 2025
A rogue abdominal artery had conspired to largely shut Andrea Fisch down. The chance meeting of Evan, the man who would become her husband, led the surgery to treat her nutcracker syndrome and SMAS that would set her free – in this case, to visit California’s Death Valley. Photo courtesy of Andrea Fisch.
A rogue abdominal artery had conspired to largely shut Andrea Fisch down. The chance meeting of Evan, the man who would become her husband, led the surgery to treat her nutcracker syndrome and SMAS that would set her free – in this case, to visit California’s Death Valley. Photo courtesy of Andrea Fisch.

The superior mesenteric artery (SMA) generally serves us well, sustaining much of the digestive tract that converts what we eat into the fuels our bodies run on. On rare occasions, though, the SMA can have a dark side. Blame an anatomical quirk that Andrea Fisch got to know all too well.

The SMA branches out of the abdominal aorta – the main highway for blood to regions south of the heart at an acute angle. It does so right above where the vein that drains blood from the left kidney cuts over to inferior vena cava, the abdominal aorta’s venous counterpart. What’s more, the duodenum, the first section of the small intestine below the stomach, also squeezes through that tight arterial intersection.

A strategic bit of visceral fat propping up the SMA keeps circulatory and digestive traffic flowing for most of us. But for some, particularly slender young women like Fisch, the SMA-abdominal aorta junction can clamp down like a vise on the left renal artery, the duodenum, or both, choking them off.

If the duodenum gets squeezed shut, it’s called superior mesentery artery syndrome, or SMAS. Also called Wilkie’s syndrome, it brings nausea, vomiting and potentially dangerous weight loss. If the left renal vein from the kidney gets blocked, it’s called nutcracker syndrome, named after implements that crush walnut shells.

Nutcracker syndrome brings a host of symptoms, but most prominently endless, knifing pain on the left side of the abdomen. Fisch, now 28, came to UCHealth University of Colorado Hospital on the Anschutz Medical Campus with both SMAS and nutcracker syndrome. Two coincidences played decisive roles in her care. One led to her finding one of the only U.S. health care center with a clinic specializing in kidney autotransplant cases – that is, the transplantation of the patient’s own left kidney to the right side of the pelvis. Research has shown autotransplantation to be the best long-term solution for nutcracker syndrome.

Fisch and her dog Marli high above the Arkansas River near Buena Vista. Photo courtesy of Andrea Fisch.
Fisch and her dog Marli high above the Arkansas River near Buena Vista. Photo courtesy of Andrea Fisch.

The other coincidence led to the autotransplant clinic’s existence in the first place.

SMAS syndrome led to extreme weight loss

Fisch’s arrival at UCHealth University of Colorado Hospital’s renal autotransplant clinic had been a long time coming. Her SMAS symptoms started during her final semester at the University of Missouri St. Louis. Then 22, she went from working out six days a week in pursuit of a physical trainer certificate to being unable to keep food down and subsisting largely on protein drinks. She felt terrible, and over a few months, her five-foot-five-inch frame went from carrying a fit 122 pounds to a skeletal 93. As often happens with SMAS, it took months to land an accurate diagnosis while friends and medical specialists wondered if anorexia or something else were at play.

A 2019 surgery to connect the duodenum above the choke point to the small intestine below it – called a duodenojejunostomy – seemed to solve the problem, and with that, Fisch picked up and moved to Colorado to start a new life. But SMAS symptoms returned within months, this time with the addition of sharp pain in her left flank that she described as “like having a kidney stone every day – 10-out-of-10 pain.” She knew to seek medical care but wasn’t sure where. A shopping trip to a metro-Denver Target would provide direction.

It was March 2020, early in the coronavirus pandemic. In the store’s aisles, Fisch noted a young man in medical scrubs. “Thanks for doing what you’re doing,” she said, and alluded to the first global pandemic in a century. Both wore surgical masks. They struck up a conversation that turned to her health challenges.

It turned out that the guy was a medical resident en route to becoming an emergency room physician, and his father was a Denver-area nephrologist. They exchanged information, and the nephrologist Dr. Bruce Fisch soon connected the woman, who would later marry his son Evan, with University of Colorado School of Medicine transplant surgeon Dr. Thomas Pshak.

A blind referral for nutcracker syndrome leads to an autotransplant clinic

Pshak had the uncommon distinction of being fellowship-trained in both urology and transplant surgery. Three years earlier, University of Wisconsin transplant surgeon Hans Sollinger, a pioneer in kidney autotransplantation for nutcracker syndrome, had referred a woman from Utah to Pshak based on those credentials.

Dr. Thomas Pshak
Dr. Thomas Pshak

Sollinger described to Pshak a test Sollinger had developed that used the anesthetic Marcaine to temporarily numb the area around the left renal artery. Doing so provided temporary relief to the patient and confirmed a nutcracker syndrome diagnosis. The woman, a triathlete whose pain had kept her from competing for years, hopped up and jogged around the recovery room.

“I was like, ‘Wait a minute – this is pretty cool,’” Pshak recalled.

He scheduled a kidney autotransplant, and the woman was soon doing triathlons again. Word got out, and referrals from around the country led to Pshak assembling a team including specialists in transplant surgery, interventional radiology, vascular surgery, psychology, and social work to diagnose and treat autotransplant patients. Pain medicine and addiction medicine specialists are also important contributors, Pshak says, because so many nutcracker syndrome patients rely on heavy pain meds to get through their days and nights.

Two ‘superior mesenteric artery’ birds with one ‘surgical’ stone

That wasn’t an issue for Fisch, who had been soldiering through on “mainly nerves of steel,” as she put it, with an assist from legal cannabis. Pshak and the renal autotransplant team used scans and the Marcaine test to confirm both nutcracker syndrome and the recurrence of SMAS, which had dropped Fisch back below 100 pounds. CU School of Medicine transplant surgeon Dr. Trevor Nydam worked with Pshak on a plan to perform both the autotransplant and a fix for the recurrent SMAS during a single surgery.

That surgery happened in early 2021, with Nydam revising the previous SMAS surgery to address the intestinal blockage and Pshak moving Fisch’s kidney. What was then an open surgery would today be done minimally invasively using a surgical robot, Pshak said. The autotransplant team performs several dozen such surgeries on nutcracker syndrome patients a year – some of whom skip the transplant itself and instead choose to donate the kidney, a process facilitated by the UCHealth Transplant Center.

The data is in: Autotransplant is a treatment for nutcracker syndrome

Together with University of Wisconsin autotransplant experts, Pshak and colleagues recently published a study on autotransplant outcomes among 105 patients with nutcracker syndrome. Among the key findings: 93% of those autotransplanted had complete pain relief a year later, and the number of patients on opioids decreased by 65%.

Renal autotransplant surgery, a treatment for nutcracker syndrome, made pain-free concerts at Red Rocks possible. Photo courtesy of Andrea Fisch.
Renal autotransplant surgery, a treatment for nutcracker syndrome, made pain-free concerts at Red Rocks possible. Photo courtesy of Andrea Fisch.

“Our study suggests that this is probably the best treatment option for nutcracker syndrome,” Pshak said.

While Fisch has moved on from the idea of becoming a personal trainer, she has no limitations on the exercise front. Should she and Evan decide to have children, there are no restrictions there, either, Pshak says. In the meantime, the couple bought a truck camper and have exploited the freedoms of youth – and Fisch’s freedom from pain – to explore the West from Colorado to California.

She is grateful to Pshak, Nydam, and their many colleagues for enabling that freedom.

“They really took me seriously from the get-go,” Fisch said. “I can’t thank them enough for that – for being surgeons who cared.”

About the author

Todd Neff has written hundreds of stories for University of Colorado Hospital and UCHealth. He covered science and the environment for the Daily Camera in Boulder, Colorado, and has taught narrative nonfiction at the University of Colorado, where he was a Ted Scripps Fellowship recipient in Environmental Journalism. He is author of “A Beard Cut Short,” a biography of a remarkable professor; “The Laser That’s Changing the World,” a history of lidar; and “From Jars to the Stars,” a history of Ball Aerospace.