Men who donate a kidney face a far higher long-term risk of needing scrotal surgery than previously understood, with new data showing male donors are nearly 40 times more likely than non-donors to undergo an operation for painful scrotal fluid build-up.
The population-based cohort study, published in Annals of Internal Medicine [link here], tracked 898 male donors in Ontario for up to 22 years and matched them 1:10 with nearly 9000 healthy nondonors. Researchers found donors had an incidence rate of 8.3 scrotal surgeries per 1000 person-years, compared with just 0.2 in nondonors – with most operations performed years after the transplant surgeon was no longer involved in their care.
Researchers from the London Health Sciences Centre Research Institute (Canada) found that more than 90% were hydrocelectomies done under general anaesthesia, typically following progressive, uncomfortable swelling on the same side as the nephrectomy.
While donation remains safe and strongly encouraged, the authors say the findings should reshape counselling, long-term follow-up, and surgical technique research to ensure male donors understand the small but meaningful risk and recognise symptoms early.
“Our findings merit action from the transplant community to safeguard the practice. Past and future male donors should be informed about the risk and advised on symptoms to monitor after donation”, the group says adding that donors should “have access to necessary medical care for any donation-related complications and should not incur a financial burden”.
Over a median nine-year follow-up – extending to a maximum of 22 years – the cumulative incidence of scrotal surgery reached 13.8% in donors versus 0.7% in nondonors, translating to one in eight donors requiring surgery over two decades (70 of 898 donors [7.8%] vs. 19 of 8980 nondonors [0.2%]; 8.3 vs. 0.2 events per 1000 person-years; hazard ratio, 38.8 [95% CI, 22.1 to 67.9]).
Most procedures were hydrocelectomies – coded as unilateral excision of the tunica vaginalis – and occurred long after the initial post-donation care had ended. The median time from donation to scrotal surgery was 5.2 years (IQR, 3.3 to 8.4 years).
According to investigators, symptoms often develop slowly, and donors may not immediately connect new discomfort to their past nephrectomy.
“Affected donors described the pain as dull, aching, heavy, and intermittent; in some donors, symptoms resolved within 3 months of their nephrectomy, while in others, symptoms persisted for years” they said. Notably, “most donors reported ipsilateral scrotal content swelling and pain.”
Reasons for hydrocele formation after donation remain uncertain but may involve disruption to fluid secretion and reabsorption balance within the tunica vaginalis – the peritoneal sac that surrounds the testis – investigators suggest. Why these collections develop – or worsen – years after surgery, and why they are more common after laparoscopic than open procedures however, is not fully understood.
The study found that rates were similarly elevated after left-sided and right-sided laparoscopic nephrectomies, suggesting causes beyond simple venous division, investigators say. While the gonadal vein is routinely divided during left-sided nephrectomy and only sometimes on the right, this alone did not explain the findings. Instead, the authors propose that subtle operative factors may be at play: “Both laparoscopic and open nephrectomies may disrupt lymphatic drainage and predispose to reflex sympathetic dystrophy from nerve damage to the spermatic plexus and cord.”
They add that the energy devices used in laparoscopic surgery may cause greater damage to these structures, potentially amplifying long-term risk.
Prof Steve Chadban
Professor Steve Chadban, nephrologist and transplant physician at Royal Prince Alfred Hospital and leader of the Kidney Node at the University of Sydney’s Charles Perkins Centre, said the data provided valuable, practice-relevant insight for clinicians.
“This is an excellent paper and generalisable to our clinical context in Australia,” he told the limbic. “It provides solid information on the incidence of a complication we’ve all seen anecdotally in male donors. By defining the incidence of scrotal surgery post-donation at one in eight, it gives us data we can use to provide more accurate pre-donation education,” he said adding that this is a “relatively benign and treatable condition, and we feel it’s unlikely to affect donor willingness to proceed”.
Despite the elevated long-term risk, the authors stress that the overall safety and social value of living kidney donation remains unchanged. “Continuing to encourage living kidney donation is vital, as the practice benefits donors, recipients, families, and society,” they write.
But they argue the findings demand more transparent counselling and better follow-up for men while adding that the true extent of morbidity of scrotal complications after living donor nephrectomy may be underestimated.
“Half of those with symptoms may not seek medical attention. They may avoid discussing sensitive topics or may wish to spare their kidney recipient from concern,” they point out.
The study notes that “past and future male donors should be informed about the risk and advised on symptoms to monitor after donation. A simple step, they suggest, is establishing a baseline before surgery.
“Including a scrotal ultrasound in the predonation evaluation would allow for documentation of baseline findings and aid in assessing donors who develop new symptoms.”
However, Professor Chadban said that would be unlikely step in Australian settings.
“Pre-transplant ultrasound wouldn’t change eligibility or surgical approach,” he said. “Living donors already undergo a large number of tests to confirm eligibility and plan surgery, so adding to that burden isn’t helpful. What matters is alerting men to watch for scrotal symptoms at any stage post-donation and to seek medical attention, ideally from their donor urologist, if they arise.”
Despite the elevated risk, Professor Chadban said the results add nuance to the conversation around donor safety, rather than changing its fundamentals. “A living-donor kidney transplant is the best form of management for most people with kidney failure,” he said. “Female donors outnumber males two to one worldwide, including in Australia, and we want to maximise living-donor potential. This paper is an excellent addition to our knowledge that will improve donor education and long-term management, but it’s certainly not a reason to reduce enthusiasm for men to consider donation.”
The authors also suggest that “analysing intraoperative video recordings may provide insights into the aspects of donor nephrectomy that affect hydrocele formation” – a potential path to safer techniques over time.
“As many countries strive to increase their rates of living kidney donation, ongoing assessment of complications and long-term risks is essential for the practice”, investigators said.