Reported Failures of the Polymer Self-Locking (Hem-O-Lok) Clip: Review of Data from the Food and Drug Administration

Abstract

Background and Purpose: New technology has played an important role in the proliferation of laparoscopy within urology. A central issue remains meticulous hemostasis, particularly for larger vessels (e.g., renal artery and vein). This paper presents available information regarding failure of the widely utilized nonabsorbable polymer Hem-o-lok clip (Weck Closure Systems, Research Triangle Park, NC), introduced in 1999. Methods: The Food and Drug Administration Center for Devices and Radiological Health maintains a compendium of reports of adverse events involving medical devices (MAUDE). We performed multiple searches of MAUDE using a variety of key words, including Weck, Hem-o-lok, laparoscopy, nephrectomy, and clip. Results: Within the MAUDE database, we identified 27 reports of problems with the Hem-o-lok clip until July 6, 2005. Of these events, only 1 (4%) involved application during open surgery, with the remainder occurring during laparoscopy. Minimal morbidity resulted from applicator difficulty during laparoscopic cholecystectomy (N = 7; 26%), with one case of open conversion. Forty-eight percent (N = 13) of the failures occurred during urologic laparoscopy; of these, bleeding was the primary problem in 77%. Delayed exploration, immediate open conversion, and death resulted in 38% (N = 5), 8% (N = 1), and 15% (N = 2), respectively. No clear etiology for the events could be found, although in all situations, multiple clips had been applied with apparent initial vessel control intraoperatively. Conclusions: Reported difficulty with the Hem-o-lok clip occurs primarily during laparoscopic surgery. Cases of failure after laparoscopic nephrectomy require urgent exploration, although it is unclear whether device or user error is the underlying cause. Regardless, care must be taken in securing the renal vessels, surgeons must be educated regarding proper use and techniques, and consideration should be given to using transfixing techniques.