Medical devices · Surgical safety
Allotrope Medical
A Houston surgical resident built a box that makes the ureter move on command, cleared it in 2020, and sold the company in 2023. StimSite is now on a national hospital purchasing contract. The published clinical evidence is one case report.
A cheek twitch across the drapes
Late in a pelvic operation, the ureter had gone missing. Scar tissue and blood had flattened the field, and the thin tube that carries urine from kidney to bladder was not doing the one thing that gives it away: the slow, worm-like squeeze surgeons hunt for before they cut.
On the other side of the drapes, the anesthesiologist pressed a nerve stimulator to the patient’s cheek to check whether the paralytic had worn off. The cheek twitched. Albert Huang, a general surgery resident, was watching.
He later told MedTech Strategist that he “looked at the anesthesiologist using the facial nerve stimulator to make the patient’s cheek twitch, which they do to see if the paralytic agent works, and thought: Well, that’s muscle and that works on electricity and it moves. The ureter is also muscle, so why can’t we use electricity to make that move?”
He built the first version from parts bought on eBay and at RadioShack. By his account he “hacked together something that looks terribly ugly, but it did what it was supposed to do.”
The problem, and what surgeons already do about it
A 2022 case report on StimSite puts the rate of clinically apparent ureteral injury at 0.2 percent to 2.5 percent in routine gynecologic operations, rising to 10 percent to 30 percent in radical cancer procedures.
The standard way to find the ureter is mechanical: dissect toward it and pinch it, provoking the contraction you are trying to see. Allotrope’s NSF abstract says the structure “is at risk of injury during dissection and pinching, the current standard surgical method, to mechanically elicit this contraction and thereby locating the ureter during surgery.”
Every alternative adds something: stents placed beforehand, lighted stents and infrared kits with their own hardware, near infrared dyes needing a compatible camera, cystoscopy at the end to find damage after the fact. Stryker sells its IRIS U-Kits on the line that the technology “is designed to help identify the ureters in lower pelvic procedures and reduce the risk of ureteral injury.” Allotrope’s bet was that the surgeon already holds the antenna: a signal box outside the sterile field sends a stimulation waveform down the bipolar grasper already in hand, through the cable that normally carries cautery.
One founder, and the Houston machine around him
Huang was a surgical resident and research fellow at Houston Methodist, later Entrepreneur in Residence at the Texas Medical Center. The company was incorporated in Delaware in 2016 and joined the first TMC accelerator cohort devoted entirely to devices that August, listed in one line: “Allotrope Medical (Houston) provides precise ureter identification during minimally invasive surgery.” It was also a resident of JLABS at TMC and appears among Y Combinator’s companies.
From breadboard to activation card
Two NSF small business awards paid for the engineering: $224,832 in 2018 to characterize the waveform, then $951,914 across 2019 and 2020 to build the product. Phase II was meant to yield a sterile single use device. It did not. Huang wrote in the closeout report that the team “pivoted into a different form factor thanks to continued customer discovery and truly listening to the voice of the customer (surgeons and hospitals).”
The pivot set the business model too. The same report describes selling procedure credits, so that “the hospital does not bear the burden of an expensive box and instead pays a nominal price for an activation card that comes pre-loaded with a certain number of clinical case uses of StimSite.” That Activation Card is named in the FDA file as a device component.
Clearance came on November 10, 2020, a $4 million Series A in June 2021, a Safer Technologies Program designation in November 2022. In April 2023 Northgate Technologies, an Elgin, Illinois maker of insufflators and smoke evacuation systems, bought the company. Terms were not disclosed. Huang became its chief medical officer.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| FDA 510(k) K200886 | Cleared Nov 10, 2020, Class II surgical nerve stimulator and locator, code ETN. Predicates: UroMed CaverMap (K993436) and Checkpoint (K092292). Indications in full: “StimSite is a non-sterile device intended to provide electrical stimulation to ureter smooth muscle tissue to help locate and identify ureters by testing ureter smooth muscle excitability.” | Public record |
| Scope of the claim | The summary calls it “an adjunct to the standard of care visual assessment currently performed by surgeons to manually stimulate muscle tissue to identify ureters during surgical procedures.” Nothing about fewer injuries or shorter operations was cleared. | Public record |
| Data in the file | Eleven procedures, Sep 2018 to Dec 2019, all gynecologic, two surgeons, 10 of 11 by one of them, no control arm. Animal work in a Yorkshire pig model: “Users were able to identify the ureters in all cases with StimSite.” Human factors testing with 5 then 19 surgeons. | Public record |
| Published evidence | No PubMed indexed paper and no registered trial as of Sep 2026. One single patient case report, Surgical Science, June 2022, disclosing: “CM has served as a Consultant for Allotrope, Cooper Surgical, and Apyx medical. Article funded by Allotrope.” | Thin |
| Safety in the field | No MAUDE adverse event reports and no recalls under the brand or either company name, six years after clearance. | Public record |
| Intellectual property | US 12,440,265, priority Jun 2020, granted Oct 14, 2025, assigned to Allotrope Medical. A continuation filed Sep 2025 is pending, as is a 2016 family on signal delivery. | Public record |
| How it is sold today | The purchasing group listing says StimSite “can verify ureter placement and pathway, as well as drastically reduce the risk of ureter injury and expedite cystoscopy procedures.” Neither benefit is in the cleared indication, and no published study supports either. | Differs from the clearance |
Read plainly: the device does what the label says. Electricity through a bipolar instrument makes the ureter contract, eleven human cases and the animal work satisfied a 510(k), and six years of use has produced no reported adverse events. What does not exist is comparative evidence. Nobody has published a series showing shorter operations, shorter cystoscopies or fewer injuries against a control. The sales copy has gotten ahead of the file.
What to watch
- A second 510(k). The 2022 announcement described a proposed additional indication around cystoscopy. None has appeared in four years.
- Any controlled data, which would turn the injury reduction language from marketing into evidence.
- The MAUDE record. A clean file six years in is meaningful; a first report would be worth reading closely.
- The continuation patent filed in September 2025, a sign the platform is still being prosecuted under the new owner.
In their words
“Whether it is a gynecologic or colorectal operation, a significant portion of OR time is spent looking for the Ureter and keeping it safe. StimSite provides surgeons with an elegant tool to help rapidly identify the ureter, keep it safe from harm, and promote the progression of a pelvic operation. It should be in the toolbox of every surgeon doing pelvic surgery.”
Brian Dunkin, MD, past president of SAGES, 2020 clearance release · Company release
“With ureter injuries being top of mind for all surgeons operating in the pelvis, we are excited to be able to offer a technology that helps surgeons identify this important structure in a simple and elegant way.”
Albert Huang, MD, founder and CEO, November 2020 · Company release
“I use StimSite to facilitate ureter efflux, and have observed a significant reduction in my post-procedure cystoscopy time.”
Richard Farnam, MD, robotic gynecologic surgeon, November 2022 · Company release
“This is the first case report in the literature describing the use of StimSite technology, which was FDA cleared in 2020 to assist with ureter identification.”
Craig McCoy, MD, Surgical Science, June 2022 · Case report
“By bringing the StimSite product platform into NTI’s existing portfolio of innovative insufflation and smoke removal products, we have taken a significant step in fulfilling our vision to optimize the surgical environment for minimally invasive surgery.”
Dave McDonough, Northgate Technologies, April 2023 · Acquirer release
“To have taken this from idea to exit has been a true honor.”
Albert Huang, MD, on LinkedIn, quoted by InnovationMap, April 2023 · Independent
Related companies
Sources
- Public recordFDA 510(k) clearance letter and summary, K200886
- Public recordopenFDA 510(k), listing, MAUDE and recall queries
- Public recordNSF SBIR awards 1746570 and 1852999
- Public recordCompany portfolio page
- Public recordForm D and Form D/A, CIK 0001702408
- Public recordUS 12,440,265 B2 and US 2021/0370062 A1
- IndependentIntraoperative Ureteral Identification Utilizing StimSite Technology
- IndependentFDA clears Allotrope StimSite
- IndependentSmooth Muscle Stimulator Helps Locate Ureters During Surgery
- IndependentHouston health tech startup acquired by medical device company
- IndependentTexas Medical Center hosts 11 device startups
- InterviewStimulating the Ureter to Streamline Surgery
- IndependentFormer Fellow’s StimSite Clears FDA
- CompanyFDA clearance of StimSite
- CompanySafer Technologies Program designation
- AcquirerNorthgate Technologies acquires Allotrope Medical
- DistributorNorthgate Technologies contract 4430 listing
- CompetitorIRIS U-Kits product page
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
