The first study to report a complementary multimodal monitoring strategy during intraoperative aneurysm clipping came from cerebrovascular neurosurgeons at the University Hospital of Padua, Italy. The group used three monitoring technologies, transit-time flowmetry, intraoperative indocyanine green video angiography (ICG-VA), and neurophysiological monitoring, to assist during microsurgical clipping of intracranial aneurysms at their institution.

They conducted a retrospective analysis of the clipping of 96 intracranial aneurysms in 85 consecutive patients over two years using all three monitoring techniques with each patient. Outcomes were evaluated by rate of aneurysm obliteration and postoperative ischemic injury. Intraoperative data were reported along with changes in each monitoring technique, depending on the aneurysm’s features.

They discovered that the aneurysm was completely obliterated in 98.9% of patients. Postoperative symptomatic ischemic injury was recorded in 2.08% aneurysms. Of the treated aneurysms, clips were repositioned in 40.6% of the cases as a result of motor evoked potential (MEP) decrease (9.3%), 25% drop after clipping measured by flowmetry (23%) and ICG-VA (8.3%). Flow changes occurred more frequently in distal rather than proximal and in atherosclerotic aneurysms. MEP impairment occurred more often in proximal aneurysms and ICG-VA disclosed remnant aneurysms mainly in atherosclerotic aneurysms.

From their study, the clinicians concluded that microsurgical aneurysm clipping using a multimodal monitoring strategy achieved a high rate of aneurysm obliteration with low morbidity. The data show that the three techniques used can be used complementarily and that a monitoring strategy can be tailored to the features of the aneurysm.

REFERENCE Della Puppa A Rossetto M, Volpin F, Rustemi O, Grego A, Gerardi A, Ortolan R, Causin F, Munari M, Scienza R., “Microsurgical clipping of intracranial aneurysms assisted by neurophysiological monitoring, microvascular flow probe and ICG-VA. Outcomes and intraoperative data on a multimodal strategy,” World Neurosurg. 2018 February 13 (Transonic Reference # 12300AH)