Staghorn Caliceal Hem-o-Lok Stone: a long-term complication of robotic partial nephrectomy: a case report and literature review.

Hem-o-Lok clips (HOLCs) are a useful tool in mini-invasive surgery, especially for renal surgery. However, in rare cases, they could migrate into the collecting system and be calculogenic. We present a case of a 53 years old man with an incidental CT finding of a left staghorn caliceal stone increasing its size in the last 2 years. He had a medical history of ipsilateral robotic partial nephrectomy (RAPN) at another institution 8 years before and a previous renal colic with spontaneous stone elimination about 20 years before. The stone was located in the upper calyx. He underwent a flexible ureteroscopy. After an initial fragmentation, a Hem-o-lok was reported, partially wedged into the renal parenchyma. After removing the HOLC with a basket, a small urinary leak was observed and managed with a JJ stent placement. In the postoperative period, the patient had a fever managed with antibiotics and was discharged on the 4th postoperative day without problems. HOLC migration into the collecting system is a rare complication following robotic and laparoscopic renal surgery. HOLC could act as a nidus for stone formation. Avoiding too much tension during renal sutures using HOLC could reduce the possibility of migration. Simple knotting in particular conditions is a valuable option. However, this kind of stone can be managed endoscopically without complaints, minding the possibility that HOLC could be partially wedged into renal parenchyma leading to a urinary leak. With the widening indications for RAPN this kind of complication could be more frequent.