Hemorrhagic complications after mini-PCNL: retrospective analysis from a single high-volume center
This retrospective analysis of 664 patients at a high-volume center demonstrates that mini-PCNL is a safe and effective procedure for treating large renal stones, associated with low rates of hemorrhagic complications, blood transfusions, and arterial embolization while preserving renal function.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Kidney stones are hard mineral deposits that form inside the kidneys, often causing severe pain and requiring medical intervention to remove. When stones become too large to pass naturally or break down with sound waves, surgeons use a procedure called percutaneous nephrolithotomy. This involves making a small opening in the back to insert a tube directly into the kidney, allowing doctors to see inside and break the stone into pieces that can be removed. While effective, this method carries a risk of bleeding, as the kidney is a highly vascular organ filled with blood vessels. If a blood vessel is nicked during the procedure, it can lead to significant blood loss, sometimes requiring a blood transfusion or a specialized intervention to seal the bleeding vessel. The medical community has long sought ways to make this surgery safer by using smaller instruments, hoping to reduce the risk of injury while still clearing the stones completely.
A team of researchers at a major hospital in Spain set out to examine how safe these smaller, "miniaturized" versions of the surgery truly are. They looked back at the records of 664 patients who underwent this procedure between 2018 and 2025. The surgeons in this study used a specific, standardized approach: they guided a needle into the kidney using X-ray imaging to hit a precise target, then expanded the path using a balloon to create a channel just large enough for their tools. This technique, known as mini-percutaneous nephrolithotomy, uses a tube no wider than 18 French (Fr), which is approximately 6 millimeters. The researchers wanted to know how often this method caused bleeding, how many patients needed blood transfusions, and whether the procedure affected kidney function in the months following the operation.
The analysis revealed that serious bleeding was a rare event. Out of the 664 patients, only 20 experienced hemorrhagic complications, which amounts to roughly 3 percent of the total group. Of those 20 patients, 19 required a blood transfusion, and 11 needed a procedure called arterial embolization, where a doctor threads a tiny catheter through the blood vessels to block the bleeding source. The average drop in hemoglobin, a protein that carries oxygen in the blood, was about 3.3 grams per deciliter. For the patients who did bleed, the stone they were removing was, on average, quite large, with a volume of 5,700 cubic millimeters. The bleeding typically started within one day of the surgery. Interestingly, the researchers found that the patients who experienced bleeding often had other health conditions, such as high blood pressure or diabetes, which are known to increase the risk of bleeding in general.
Despite these complications, the study found that the procedure did not harm the long-term health of the kidneys. When the researchers checked the patients' kidney function three months after the surgery, there was no significant decline, even in those who had required embolization to stop the bleeding. This suggests that the specialized techniques used to seal the bleeding vessels were precise enough to save the surrounding healthy tissue. The study also noted that the surgeons used a specific method of puncturing the kidney, aiming through the center of the kidney's filtering units, and expanded the entry path with a balloon rather than a rigid metal dilator. The authors suggest that this combination of a careful entry path and gentle expansion likely contributed to the low rate of severe bleeding they observed.
The researchers concluded that miniaturized percutaneous nephrolithotomy is a safe and effective option for treating large kidney stones, even in complex cases. They emphasized that their findings are based on a single, high-volume center where the surgical team followed a strict, consistent protocol. While the results are encouraging, the authors noted that because the number of severe bleeding events was relatively small, they could not definitively prove which specific factor prevented the bleeding. They called for larger studies involving multiple hospitals to confirm these results and to better understand which patients might be at higher risk. For now, the data supports the idea that using smaller instruments and careful, standardized techniques can minimize the risk of bleeding while successfully removing difficult stones.
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