Optimal use of temporary clip application during aneurysm surgery – In search of the holy grail

Abstract

Temporary clips are invaluable safety tools during the clipping of an aneurysm. Controversies regarding maximum permissible duration and safety, however, remain unanswered. This descriptive narrative attempts to review the literature to provide valuable insights on controversies clouding the use of temporary clips among neurosurgeons. Popular databases, including Pub Med, Medline/Medscape, Scopus, Cochrane, Embase, Google Scholar, were searched to find available literature on temporary clips. The searched MeSH terms were “Temporary Clip,” “Temporary Clipping,” “Cerebral Aneurysm,” and “Aneurysm.” Temporary clips have been in use since 1928 and have undergone considerable structural and technical modifications. A temporary clip's optimal safety limit is not yet defined with literature evidence ranging from immediate to 93 min. It is not yet definite whether temporary clips application aggravates vasospasm, but emergency temporary clips application, especially in poor-grade aneurysmal subarachnoid hemorrhage patients, is associated with poor outcomes. A temporary clip needs to be applied with caution in patients treated earlier by endovascular technique and having indwelling stents. Nitinol Stent is feasible, while a Cobalt-Chromium alloy stent does not get occluded and gets deformed under the closing pressure of a temporary clip. Although a temporary clip application is a fundamental strategy during the clipping of an aneurysm; the exact safe duration remains to be decided in randomized control trials. Their utility for the shorter duration is beneficial under un-conclusive evidence of neuroprotective agents and intraoperative monitoring. Neurosurgeons need to consider all aspects of their pros and cons for optimal use.

Adverse events associated with microsurgial treatment for ruptured intracerebral aneurysms: a prospective nationwide study on subarachnoid haemorrhage in Sweden

“…Several factors have impact on the safety of the occlusion time, such as sedation, ventilation and collaterals. Previous studies have shown that temporary occlusion for more than 5 min can cause harmful ischaemia, while occlusion for less than 5 min is usually safe 6 28 29. Therefore, 5 min is generally considered a cut-off time in neurosurgical practice.…”

Adenosine-Assisted Clipping of Intracranial Aneurysms

“…Prolonged temporary clip placement also increases ischemic risks 4. Rarely, temporary clips can result in vasospasm of the parent arteries 3,4…”

“…Therefore, it is crucial that a variety of tools and strategies exist for use during intracranial aneurysm clipping to combat any potential challenges that may arise. Although a variety of techniques exist to reduce blood flow to and through the aneurysm during dissection and clipping, temporary arterial occlusion via placement of temporary clips on the parent vessels is the most reliable 2,3. Placement, however, can be challenging if the rupture occurs early or if the anatomy does not facilitate complete trapping.…”

Adenosine-Assisted Clipping of Intracranial Aneurysms

“…4 Rarely, temporary clips can result in vasospasm of the parent arteries. 3,4 An alternative to temporary clipping is systemic flow arrest through the IV administration of adenosine. Adenosine administered as a bolus transiently slows sinus rate and atrioventricular (AV) nodal conduction resulting in brief asystole.…”