Table 2.
Surgical events
| Type | Specific complication | Number of papers reporting | Median complication rate | Min | Max |
| Arterial injury | Arterial injury/occlusion (any) | 7 | 3.8% | 1.1% | 7.1% |
| Arterial injury/occlusion (not further specified) | 4 | 4.6% | 1.1% | 7.1% | |
| Arterial occlusion - large vessel | 3 | 2.9% | 2.7% | 6.1% | |
| Arterial occlusion - perforator | 1 | 3.8% | 3.8% | 3.8% | |
| Arterial stenosis | 1 | 0.6% | 0.6% | 0.6% | |
| Distal embolus | 1 | 0.6% | 0.6% | 0.6% | |
| Major haemorrhage | 1 | 6.3% | 6.3% | 6.3% | |
| Suboptimal clip placement recognised by angiography/Doppler | 2 | 15.5% | 11.9% | 19.0% | |
| Incomplete securing of aneurysm | Partial occlusion with neck remnant | 3 | 5.4% | 3.9% | 10.5% |
| Partial occlusion with incompletely secure rupture point | 2 | 3.1% | 2.8% | 3.4% | |
| Surgery abandoned | 1 | 0.8% | 0.8% | 0.8% | |
| Increased operative difficulty | Difficult operative exposure | 1 | 35.3% | 35.3% | 35.3% |
| Intraoperative rupture (any stage) | 22 | 16.6% | 0.6% | 39.1% | |
| Intraoperative rupture (during exposure) | 4 | 1.1% | 0.4% | 5.0% | |
| Intraoperative rupture (during aneurysm dissection) | 4 | 18.6% | 2.9% | 24.0% | |
| Intraoperative rupture (during clip application or manipulation) | 4 | 6.7% | 0.9% | 9.4% | |
| Parent vessel vasospasm | 1 | 9.1% | 9.1% | 9.1% | |
| Swollen brain | 3 | 5.6% | 2.8% | 8.5% | |
| Technical failure (non-release of aneurysm clip) | 1 | 0.4% | 0.4% | 0.4% | |
| Intervention | Administration of local vasodilators | 1 | 1.1% | 1.1% | 1.1% |
| Cerebral angiogram (intraop or within 2 h) | 1 | 9.2% | 9.2% | 9.2% | |
| Further neurosurgery (including bypass) | 3 | 0.6% | 0.5% | 0.6% | |
| ICP monitor | 1 | 2.9% | 2.9% | 2.9% | |
| Lumbar drain | 1 | 31.9% | 31.9% | 31.9% | |
| Temporary clipping (any) | 9 | 44.5% | 13.2% | 76.2% | |
| Temporary clipping < 10 min | 1 | 27.9% | 27.9% | 27.9% | |
| Temporary clipping > 20 min | 1 | 5.8% | 5.8% | 5.8% | |
| Temporary clipping 10–20 min | 1 | 10.4% | 10.4% | 10.4% | |
| Temporary clipping of ACA | 1 | 21.6% | 21.6% | 21.6% | |
| Temporary clipping of ICA | 1 | 8.9% | 8.9% | 8.9% | |
| Non-arterial injury | Cranial nerve injury | 1 | 2.2% | 2.2% | 2.2% |
| CSF leak | 1 | 1.1% | 1.1% | 1.1% | |
| Derangement of neuromonitoring | 1 | 24.1% | 24.1% | 24.1% | |
| Direct trauma to brain parenchyma | 2 | 0.6% | 0.6% | 0.6% | |
| Eye injury | 1 | 0.6% | 0.6% | 0.6% | |
| New subarachnoid haemorrhage or ICH | 2 | 1.0% | 0.4% | 1.6% |