Indications, techniques, outcomes, and limitations for minimally ischemic and off-clamp partial nephrectomy: a systematic review of the literature

Abstract

Context: On-clamp partial nephrectomy (PN) has been considered the standard approach to minimize intraoperative bleeding and thus achieve adequate control of tumor margins. The potential negative impact of ischemia on renal function (RF) led to the development of techniques to minimize or avoid renal ischemia, such as off-clamp PN and minimally ischemic PN techniques.

Objective: To review current evidence on the indications and techniques for and outcomes of minimally ischemic and off-clamp PN.

Evidence acquisition: A systematic review of English-language publications on PN without a main renal artery clamp from January 2005 to July 2014 was performed using the Medline, Embase, and Web of Science databases.

Evidence synthesis: The searches retrieved 52 papers. Off-clamp PN has been more commonly applied to small and peripheral renal tumors, while minimally ischemic PN is best suited for hilar and medially located renal tumors. These approaches are associated with increased intraoperative blood loss and perioperative transfusion rates compared to on-clamp PN. Minimally ischemic and off-clamp PN have potential functional benefits when longer ischemia time is anticipated, particularly for patients with lower baseline RF. Limitations include the lack of prospective randomized trials comparing minimally ischemic and off-clamp to on-clamp techniques, and the small sample size and short follow-up of most published series. The impact of different resection and renorrhaphy techniques on postoperative RF and its assessment via renal scintigraphy requires further investigations.

Conclusions: Minimally ischemic and off-clamp PN are established procedures that may be particularly applicable for patients with decreased baseline RF. However, these techniques are technically demanding, with potential for increased blood loss, and require considerable experience with PN surgery. The role of ischemia in patients with a contralateral healthy kidney and consequently an indication for elective minimally ischemic or off-clamp PN remains a debatable issue.

Patient summary: In this review we analyzed available evidence on minimally ischemic and off-clamp partial nephrectomy. These techniques, although technically demanding, may be particularly applicable for patients with decreased baseline renal function.

Keywords: Clampless; Ischemia; Off-clamp; Parenchymal clamp; Partial nephrectomy; Segmental clamp; Selective clamp; Unclamped; Zero-ischemia.