Temporary clipping in aneurysm surgery is an important step which allows the surgeon to dissect the aneurysm neck and place the permanent clip more confidently. However, there are numerous complications associated with the usage of temporary clipping. The maximum safe limit to use temporary clipping is also a topic of debate since long back. We try to enumerate the complications encountered in our institute in 50 consecutive cases of aneurysms where temporary clips are used.
A cross-sectional observational study was conducted on 50 cases of intracranial aneurysms, and data were recorded from those cases, in which atheromatous vessels were identified intraoperatively. Complications associated with the usage of temporary clips in these cases were categorised and studied.
The mean age of the study population was 55.86 years. About 32% of the study population were male. The average body mass index of the study population was 24.5. About 72% of the study group were hypertensive, and 44% were diabetic [Table 1].
The World Federation of Neurosurgical Societies grading was used at admission to prognosticate the patients, and the observations are shown in [Table 2].
Most of the aneurysms were in anterior circulation (88%). Majority of aneurysms were small in size (<7 mm), and the mean neck size was 4.8 mm [Table 3].
The average frequency of usage of temporary in each case was 3.08 times, and the longest clip used was for 8 min. The atheromatous proximal vessel as identified intraoperatively was seen in 60% of the cases.
The complications encountered in post-operative period were multiple lacunar infarcts (12%), massive infarcts along the parent vessel (4%) and vasospasm (16%) [Table 4].
Temporary clipping is a benefit in disguise. Questions regarding the optimal duration of the temporary clip, single versus intermittent use, use of intraoperative monitoring and whether conditioning is beneficial to remain unanswered. Even with a better understanding of the disease, improved neuroanaesthesia techniques and brain protection strategies, vascular surgeons are hesitant to use temporary clips. Application of temporary clips over atheromatous proximal vessels is associated with inadvertent complications due to micro-thromboembolism. This may result in delayed ischaemic neurological deficits (DIND) and delayed cerebral infarcts (DCI).
Computed tomography scan has been the most widely used radiological modality for establishing DIND and DCI. Diffusion-weighted magnetic resonance imaging can diagnose even silent ischaemic events in the order of 9.8% per treated aneurysm, according to Krayenbühl et al., who reported one symptomatic and five silent ischaemic lesions of 51 aneurysm patients.
It has been established that temporary clips applied under brain protection for a few minutes, ideally, should not be causing ischaemic deficits. In the long-term follow-up study of 382 patients with subarachnoid haemorrhage (SAH) and 246 patients with unruptured aneurysms, temporary clipping did not affect the long-term outcomes. The mean duration of total temporary artery occlusion was 19.4 min in the SAH group and 16.1 min in the unruptured group.[2,3] The same duration (20 min) has been found in another study. In our study, the maximum duration of temporary clipping was 8 min.
It has been observed that multiple intermittent clipping is better than single-time prolonged clipping. Intermittent clipping allows for establishing the reperfusion and thus reduces the chances of ischaemia. Kashkoush et al. described a median time of 3.3 min for the return of somatosensory evoked potential findings to baseline following temporary clip readjustment.
Temporary clip application is one of the dependable steps in aneurysm surgery, and it boosts the confidence of the surgeon while dissecting the neck and applying permanent clips. However, the maximum safe limits regarding duration, intermittent clipping and clipping over atheromatous vessel are still the areas to be explored. Further research in this field might help in laying down strong recommendations in using temporary clips.
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Conflicts of interest
There are no conflicts of interest.
1. Krayenbühl N, Erdem E, Oinas M, Krisht AF. Symptomatic and silent ischemia associated with microsurgical clipping of intracranial aneurysms: Evaluation with diffusion-weighted MRI Stroke. 2009;40:129–33
2. Griessenauer CJ, Poston TL, Shoja MM, Mortazavi MM, Falola M, Tubbs RS, et al The impact of temporary artery occlusion during intracranial aneurysm surgery on long-term clinical outcome: Part I. Patients with subarachnoid hemorrhage World Neurosurg. 2014;82:140–8
3. Griessenauer CJ, Poston TL, Shoja MM, Mortazavi MM, Falola M, Tubbs RS, et al The impact of temporary artery occlusion during intracranial aneurysm surgery on long-term clinical outcome: Part II. The patient who undergoes elective clipping World Neurosurg. 2014;82:402–8
4. Ogilvy CS, Carter BS, Kaplan S, Rich C, Crowell RM. Temporary vessel occlusion for aneurysm surgery: Risk factors for stroke in patients protected by induced hypothermia and hypertension and intravenous mannitol administration J Neurosurg. 1996;84:785–91
5. Kashkoush AI, Jankowitz BT, Gardner P, Friedlander RM, Chang YF, Crammond DJ, et al Somatosensory evoked potentials during temporary arterial occlusion for intracranial aneurysm surgery: Predictive value for perioperative stroke World Neurosurg. 2017;104:442–51