Patients and aneurysm characteristics:
A total of 34 patients (all ruptured except one, 97%) were treated (M:F=1:2.3). Four patients (12%) each had preoperative seizures and neurological deficits at presentation, respectively. Eleven patients (32.4%) patients presented with poor preoperative clinical grades (WFNS III or more). 6 patients (18%) had multiple aneurysms while the patient with unruptured aneurysm was previously operated for a tentorial meningioma. Table 1 shows the baseline characteristics of our patient cohort.
Of the 19 patients with distal DACA aneurysms, 5 were males and 14 were females (M:F=1:2.8). The median age of presentation was 50 years (IQR: 38 – 56). The proportion of patients with poor clinical grade at presentation was relatively high (n=9, 47.3%). Three out of 19 patients had more than one aneurysm (15.8%). Two (10.5%) patients each had seizures and hemiparesis. 52.6% (n=10) had associated intraventricular or intraparenchymal hemorrhage and 1 patient had left ACA territory in the preoperative NCCT head.
Of the 15 patients with proximal DACA aneurysms, 5 were males and 10 were females (M:F=1:2). The median age of presentation was 55 years (IQR: 35 – 61). Majority of them presented with good clinical grades (n=13, 86.7%). Multiple aneurysms were present in 3 patients (20%). 2 patients had seizure (13.3%) and another 1 patient had hemiparesis (6.7%). Four of these 15 patients (26.7%) had associated intraventricular hemorrhage or intraparenchymal hemorrhage.
Table 2 shows the differences between distal and proximal DACA aneurysms. On comparing the two groups, no statistical difference with respect to demographic profile, presence of multiple aneurysms, associated intraventricular or intraparenchymal hemorrhage and the time interval from ictus to surgery was found. Clinical grade at presentation was however significantly different. The poor clinical grade at presentation was more likely in patients with distal DACA aneurysm (n=9, 47.4%) in contrast to (n=2, 13.3%) with proximal DACA aneurysm (p=0.039).
Surgical findings:
We employed basal approaches in 4 patients (11.9%) while a vertex down approach was performed in 30 patients (88.1%). The median duration of surgery from ictus was 7 days (IQR: 3 – 9.75). Temporary clipping was performed in a total of 18 patients (52.9%). The frequency of temporary clipping was higher for distal aneurysms (13/18, 72.2%) (p = 0.042). Intraoperative aneurysm rupture was encountered in 11 (32.4%) patients, majority of which were for distal aneurysms (n=9, 81.8%) (p = 0.035). A vertex first approach most often exposed the distal artery first due to the natural trajectory. It was not the case for proximal aneurysms. In majority of the case of distal aneurysms, the distal vessel was exposed first in 16 cases (84.2%), while for proximal aneurysms, the segment proximal to the aneurysm was visualized first in 10 patients (66.7%) and the dome of the aneurysm was seen first in one case (6.7%) (p = 0.002).
Functional outcomes at discharge:
58.8% of the patients (n=20) had favorable functional outcomes at discharge. 2 patients (5.8%) died during their perioperative period. Only 3 (20%) patients had unfavourable outcome with proximal aneurysms with no mortality, even at follow-up. On the other hand, 11 (57.9%) patients with distal aneurysms had an unfavorable outcome, with 2 deaths during the peri-operative stay. While one death was due to the worsening of end-stage renal disease, the other patient died from the poor neurological status despite the surgery.
Of the 14 patients with unfavourable outcomes, majority were females (n = 10, 71.4%), harbored distal aneurysm (n = 11, 78.6%) (p = 0.026) and had poor WFNS grade (3 or more) at presentation (n = 9, 64.3%) (p = 0.002). Majority (n=13, 92.8%) of these patients had a vertex first approach done for the aneurysm clipping, 6 patients (42.8%) had an intraoperative aneurysm rupture (p=0.458). Almost all these aneurysm clippings were conducted under temporary control (n=13, p <0.001).
Surgical approach and outcomes to the subcallosal aneurysms, the grey zone:
We had 10 patients with a sub callosal aneurysm just beneath the genu of the corpus callosum (29.4%). Nine of these were approached by a unilateral anterior interhemispheric approach and the bifrontal basal interhemispheric approach was employed in the remaining patient (10%). Except for one intraoperative rupture and one perioperative death (unilateral anterior interhemispheric approach), there was no difference in completeness of aneurysm occlusion, perioperative complications, and functional outcomes.
Long term functional outcomes and predictors:
The median duration of follow-up was 12 months (IQR: 2 – 54 months). Four more (12.5%) expired during the follow-up and these patients were discharged at mRS grade 5. Two patients (6.2%) developed pulmonary complications and succumbed to death. We noted a delayed improvement in the functional status with the proportion of patients with favorable outcomes increasing from 58.8% (n=20) at discharge to 73.5%(n=25). For proximal aneurysms, favourable functional outcomes at discharge and at last follow-up were 80% (n=12) and 86.7% (n=13) respectively. Similar figures for the distal aneurysms were 42.1% (n=8) and 63.2% (n=12) respectively.
Table 3 shows the uni and multivariate analysis findings. On univariate analysis, unfavorable long term functional outcomes were associated with poor WFNS grade (3 or more) at presentation (OR = 16.2; 95%CI = 2.61 – 100.4), those where temporary clips were applied (OR = 39; 95CI = 4.02 – 378.2) and those who had distal DACA aneurysms (OR = 5.5; 95CI = 1.15 – 26.14). On multivariate analysis, only WFNS grade (>2) at presentation (OR = 13.75; 95CI = 1.2 – 157.7) (p = 0.035) and application of temporary clips (AOR = 34.32; 95CI = 2.59 – 454.1) (p = 0.007) were found to independently predict functional patients’ outcome.