Introduction

Laparoscopic and robotic partial nephrectomy (PN), which are minimally invasive surgeries, have become popular and established as standard treatments for localized renal cancer. These surgeries are still technically challenging. Especially, renorrhaphy is a stressful part to shorten warm ischemic time. LAPRA-TY clip (Ethicon Endosurgery, Cincinnati, OH, USA) is used to reduce the ischemic time and make the surgery easier because it secures the sutures quickly, unlike the conventional knot tying during renorrhaphy. However, the clips may be moved into the renal parenchyma and misdiagnosed as urinary stones.

Case Report

A 57-years-old female presented with a sudden right flank pain in emergency room. She had undergone laparoscopic PN 3 months earlier. The operation was performed for a 1.5 cm sized, totally endophytic tumor at mid pole. The tumor had been excised with anterior segmental arterial clamping. A small defect in the collecting system was repaired using a 3-0 vicryl. Tightness had been achieved by Lapra-ty clipping. The absorbable fibrin sealant product had been applied to the parenchymal bed. Continuous running sutures with 2-0 vicryl have been used for parenchymal and capsular closures. Operation and warm ischemic time was 80 min and 21 min. The bleeding amount had been about 100 cc, and the postoperative course had been uneventful. Pathologic result had been a 1.2x1 cm sized renomedullary interstitial cell tumor. Her flank pain was radiating to the right groin. Urinalysis showed microscopic hematuria and pyuria. Abdominopelvic computed tomography (CT) scan showed a 4 mm stone in the left upper ureter (hounsfield unit: 159) and grade 2 hydronephrosis (Figure 1). Another 3 mm stone was also detected in the left upper calyx. The two stones were radiolucent on plain X-ray. Rigid ureteroscopy revealed LAPRA-TY clip, which were embedded in the upper ureter and misdiagnosed as urinary stones (Figure 2). The clip was fragmented using Holmium laser lithotripsy and removed with a stone basket. Additional flexible ureterorenoscopy revealed another LAPRA-TY clip in the upper calyx. It was also taken out using a stone basket. The removed clips were broken but not calcified. The operation time was 15 min. The pain and hydronephrosis were resolved at follow-up.

Discussion

Surgical clips may migrate to abnormal positions in urologic surgeries. Metal clips have been found in the bladder and urethra after radical prostatectomy in several cases (1). The clips might induce voiding difficulty and urinary infection (2). Furthermore, the clips may act as niduses for stone formation when they are in contact with urine (3). The migration of surgical clips into the collecting system is rare, but has been consistently reported after laparoscopic and robotic PN. Rare cases of ureteral migration of Hem-O-Lok clips (Teleflex, Research Triangle Park, NC, USA) after PN have been reported (4,5). The clips were misdiagnosed as urinary stones and removed with endoscopic surgery. A similar case with absorbable LAPRA-TY suture clips has been reported after PN. It was found in the collecting system and misdiagnosed as urinary stone (6).

Migrated surgical clips showed similar findings of urinary stones on imaging study. Hem-O-Lok clips are radiopaque on CT images with 223 to 570 HU (5,7). The clip can be suspected as it shows a curved design in the early stage after surgery, but as the calcification worsens, the shape of the clip disappears. In this study, it was initially diagnosed as a urinary stone because the patient complained of colicky flank pain and hyperdense lesions in the ureter and calyx on CT images. However, CT showed HU of 152, which was lower than that of stone and appeared radiolucent on plain X-ray. These migrated clips can be found in days or years after surgery (6,8). If there are no symptoms, it can be discovered incidentally on imaging studies and diagnosed as urinary stones. After symptoms develop, they can be passed spontaneously after conservative treatment, but they can also be removed through endoscopic surgery.

There are some hypotheses as to why the surgical clips migrated to the collecting system after PN. If the operative view during renorrphay is not secured due to severe bleeding, the clipping to knot will be inaccurate, and as a result, the clip will be deep into the collecting system. And excessive tension on the suture will also cause the clip to move (5). Therefore, if LAPRA-TY clipping is incorrectly performed in the renal bed, careful observation and treatment are required. In this study, even after clamping the renal segmental artery, there was bleeding, so accurate operative view was unclear. And, clipping was performed while pulling excessively after the sutures.

Conclusion

Intrarenal movement of LAPRA-TY clip after PN is very rare, but it is possible. As in our case, the migrated clips into the collecting system can obstruct the ureter and induce similar symptoms and CT findings of urinary stone. During PN, clear operative view should be ensured, and excessive tension to the suture knot should be avoided to prevent migration of the clip.

Ethics

Informed Consent: Written informed consent was omittable and the omission was also approved.

Peer-review: Externally peer-reviewed.

Authorship Contributions

Surgical and Medical Practices: I.Y.S., T.H.O., Concept: I.Y.S., Design: I.Y.S., Data Collection or Processing: T.H.O., Analysis or Interpretation: I.Y.S., Literature Search: T.H.O., Writing: I.Y.S.

Conflict of Interest: No conflict of interest was declared by the authors.