Microsurgical clipping of intracranial aneurysms requires meticulous technique and is usually performed through open approaches. Endoscopic endonasal clipping of intracranial aneurysms may use the same techniques through an alternative corridor.
To enhance visual confirmation of regional anatomy, endoscopy was introduced.
Clipping is an important technique for intracranial aneurysm surgery. Although clip mechanisms and features have been refined, little attention has been paid to clip appliers. Clip closure is traditionally achieved by opening the grip of the clip applier. Sato et al.. reconsidered this motion and identified an important drawback, namely that the standard applier holding power decreased at the moment of clip release, which could lead to unstable clip application develop a forceps to address this clip applier design flaw.The new clip applier has a non–cross-type fulcrum that is closed at the time of clip release, with an action similar to that of a bipolar forceps or scissors. Thus, a surgeon can steadily apply the clip from various angles. They successfully used the clip applier to treat 103 aneurysms. Although training was required to ensure smooth applier use, no difficulties associated with applier use were noted. This clip applier can improve clipping surgery safety because it offers additional stability during clip release. 1).
Clipping is an independent risk factor for the development of early cerebral infarcts, whereas delayed cerebral infarcts are associated with angiographic vasospasm. Early cerebral infarcts are stronger predictors of worse outcome than delayed infarction 2).
A challenge is to ensure noninclusion of normal vessel/perforators within the clip and perform complete aneurysmal isolation. This is done with either intraoperative microvascular Doppler sonography (IMD) or Indocyanine green videoangiography (ICG-VA) as they are simple and safe. Anesthesiologists administer ICG and also help perform IMD. ICG-VA appropriately assessed vessel patency and aneurysm obliteration in 93.5% of 109 aneurysms clipped 3) However, ICG can cause transient oxygen desaturation 4). IMD use confirms aneurysm isolation and patency of parent vessel and branching arteries. Hui et al. observed that clip repositioning was required based on IMD findings in 24% of aneurysms clipped in 91 patients and concluded that IMD could reduce the rate of residual aneurysm and unanticipated vessel stenosis 5).
The complete clipping of a cerebral aneurysm usually warrants its sustained occlusion, while clip remnants may have far-reaching consequences. The aim of this study is to identify the risk factors for clip remnants requiring retreatment and/or exhibiting growth. METHODS All consecutive patients with primary aneurysm clipping performed at University Hospital of Essen between January 1, 2003, and December 31, 2013, were eligible for this study. Aneurysm occlusion was judged on obligatory postoperative digital subtraction angiography and the need for repeated vascular control. The identified clip remnants were correlated with various demographic and clinical characteristics of the patients, aneurysm features, and surgery-related aspects. RESULTS Of 616 primarily clipped aneurysms, postoperative angiography revealed 112 aneurysms (18%) with clip remnants requiring further control (n = 91) or direct retreatment (n = 21). Seven remnants exhibited growth during follow-up, whereas 2 cases were associated with aneurysmal bleeding. Therefore, a total of 28 aneurysms (4.5%) were retreated as clip remnants (range 1 day to 67 months after clipping). In the multivariate analysis, the need for retreatment of clip remnant was correlated with the aneurysm's initial size (> 12 mm; OR 3.22; p = 0.035) and location (anterior cerebral artery > internal carotid artery > posterior circulation > middle cerebral artery; OR 1.85; p = 0.003). Younger age with a cutoff at 45 years (OR 33.31; p = 0.004) was the only independent predictor for remnant growth. CONCLUSIONS The size and location of the aneurysm are the main risk factors for clip remnants requiring retreatment. Because of the risk for growth, younger individuals (< 45 years old) with clip remnants require a long-term (> 5 years) vascular follow-up. Clinical trial registration no: DRKS00008749 (Deutsches Register Klinischer Studien) 6).
Total index hospitalization costs for clipping are lower than for coiling. Costs of clipping and coiling are driven by different clinical variables. The cost of coils and devices is the predominant contributor to the higher total costs of coiling 7).
The mechanisms underlying neurocognitive changes after surgical clipping of unruptured intracranial aneurysms (UIAs) are poorly understood.
Minimal structural damage visualized on T2-weighted images at 6 months as a result of factors such as pial/microvascular injury and excessive retraction during surgical manipulation could cause subtle but significant negative effects on postoperative neurocognitive function after surgical clipping of a UIA. However, this detrimental effect was small, and based on the group-rate analysis
Successful and meticulous surgical clipping of a UIA does not adversely affect postoperative cognitive function 8).
Results of treatment after clipping and coiling do not differ in total for all patients, but differ depending on the presence of bleeding. Patients with bleeding aneurysms achieve better outcomes after coiling, and patients with non-bleeding aneurysms achieve better outcomes after clipping 9).
Abdulrauf et al. attempted to assess the potential added benefit to patient outcomes of “awake” neurological testing when compared with standard neurophysiological testing performed under general anesthesia. The procedure is performed after the induction of conscious sedation, and for the neurological testing, the patient is fully awake.
They conducted an institutional review board-approved prospective study of clipping unruptured intracranial aneurysms (UIAs) in 30 consecutive adult patients who underwent awake clipping. The end points were the incidence of stroke/cerebrovascular accident (CVA), death, discharge to a long-term facility, length of stay, and 30-day modified Rankin Scale score. All clinical and neurophysiological intraoperative monitoring data were recorded.
The median patient age was 52 years (range 27-63 years); 19 (63%) female and 11 (37%) male patients were included. Twenty-seven (90%) aneurysms were anterior, and 3 (10%) were posterior circulation aneurysms. Five (17%) had been coiled previously, 3 (10%) had been clipped previously, 2 (7%) were partially calcified, and 2 (7%) were fusiform aneurysms. Three patients developed synchronous clinical neurological and neurophysiological changes during temporary clipping with consequent removal of the temporary clip and reversal of those clinical and neurophysiological changes. Three patients developed asynchronous clinical neurological and neurophysiological changes. These 3 patients developed hemiparesis without changes in neurophysiological monitoring results. One patient developed linked clinical neurological and neurophysiological changes during final clipping that were not reversed by reapplication of the clip, and the patient had a CVA. Four patients with internal carotid artery ophthalmic segment aneurysms underwent visual testing with final clipping, and 1 of these patients required repositioning of the clip. Three patients who required permanent occlusion of a vessel as part of their aneurysm treatment underwent a 10-minute intraoperative clinical respective-vessel test occlusion. The median length of stay was 3 days (range 1-5 days). The median modified Rankin Scale score was 1 (range 0-3). All of the patients were discharged to home from the hospital except for 1 who developed a CVA and was discharged to a rehabilitation facility. There were no deaths in this series.
The 3 patients who developed neurological deterioration without a concomitant neurophysiological finding during temporary clipping revealed a potential advantage of awake aneurysm surgery (i.e., in decreasing the risk of ischemic injury) 10).
Retrospective review of the medical records of 320 patients with 416 aneurysms treated with microsurgical clipping from 2008 to 2016 in a single neurosurgical center in Brazil. This study evaluated postoperative outcome, using the modified Rankin Scale (mRS) on hospital discharge, treatment efficacy, assessed by digital subtraction angiography (DSA) performed postoperatively, and mortality.
Among 320 patients with aneurysms, 228 patients presented with ruptured aneurysms and 92 patients with unruptured aneurysms. Overall, 81 (26,3%) presented poor outcome (mRs>2) while 227 (73,4%) showed good outcome. The presence of a ruptured aneurysm was a statistically significant factor for poor outcome (p<0,001) and mortality (p<0,015). Giant and large aneurysms were also associated with poor outcome (p=0,004). When we analyze separately, unruptured aneurysms with poor outcome were only associated with aneurysms size. Among the patients with ruptured aneurysms, those with Hunt Hess (HH) > 2 on hospital admission showed unfavorable outcomes (p<0,0001). Among patients submitted to postoperative DSA, 207 (89,8%) had complete occlusion of the aneurysms and 24 (10,2%) presented residual aneurysms, with reoperation required in eight cases.
Microsurgical treatment of intracranial aneurysms is an effective and safe method 11).