Out of the 17 patients 9 were women and 8 were men. The mean age at the time of surgery was 62 years (range, 31–75 years). The majority of patients (14/17) presented with SAH.
The severity of SAH at presentation, according to the Hess and Hunt classification, was as follows: four patients were classified as grade 2, four as grade 3, two as grade 4, and four as grade 5. Two patients had a history of previous SAH due to the rupture of an aneurysm at a different location. The medical history and the clinical state at admission are shown in Table 1.
Table 1
Demographic and clinical data of 17 patients with aneurysms in the posterior fossa operated in the semi-sitting position
|
Age
|
Sex
|
BMI, kg/m²
|
Medical history
|
Clinical
presentation
|
1
|
54
|
F
|
24
|
HTN, AF, COPD
|
SAH Hunt and Hess grade 5
|
2
|
60
|
M
|
30.4
|
HTN, CHD, hypercholesterolemia, DM, SM
|
SAH Hunt and Hess grade 3
|
3
|
51
|
M
|
26.2
|
CHD, COPD, SM
|
SAH Hunt and Hess grade 2
|
4
|
71
|
F
|
29.1
|
HTN, HF, asthma
|
SAH Hunt and Hess grade 5
|
5
|
74
|
F
|
23.9
|
HTN, COPD, SM
|
SAH Hunt and Hess grade 3
|
6
|
70
|
M
|
24.7
|
HTN, CHD, MR, CEA
|
SAH Hunt and Hess grade 2
|
7
|
75
|
M
|
24.8
|
HTN
|
SAH Hunt and Hess grade 2
|
8
|
65
|
F
|
24.9
|
HTN, stroke, COPD, SM
|
SAH Hunt and Hess grade 3
|
9
|
67
|
M
|
27.8
|
HTN, DM
|
SAH Hunt and Hess grade 5
|
10
|
39
|
M
|
27
|
Ulcerative colitis, cocaine addiction
|
SAH Hunt and Hess grade 2
|
11
|
71
|
M
|
19
|
HTN, COPD, DM, CHD, PAD, SM
|
SAH Hunt and Hess grade 4
|
12
|
64
|
M
|
24.8
|
HTN, DM, SM
|
SAH Hunt and Hess grade 5
|
13
|
63
|
F
|
25.5
|
None
|
SAH Hunt and Hess grade 3
|
14
|
55
|
F
|
24.9
|
COPD, history of SAH, rheumatoid arthritis, dissection of right VA
|
SAH Hunt and Hess grade 4
|
15
|
61
|
F
|
31.6
|
HTN, SM, obesity, Raynaud's syndrome, hypercholesterolemia
|
Incidental, headache
|
16
|
31
|
F
|
19.70
|
History of SAH with coiling of PICA-aneurysm Hunt and Hess grade 3. Reperfusion of the aneurysm 8 months after coiling, HTN, SM
|
Incidental, headache
|
17
|
53
|
F
|
24.2
|
MS, SM, depression
|
Incidental, headache
|
F=female, M=male, HTN=arterial hypertension, AF=atrial fibrillation, COPD=chronic obstructive pulmonary disease, DM=diabetes mellitus, H&H=Hunt and Hess grading, SM=smoking, HF=heart failure, MR=mitral regurgitation, CHD=coronary heart disease, CEA=carotid endarterectomy, MS= Multiple sclerosis:
Of the 14 patients presenting with SAH, 12 had ruptured aneurysms of the posterior inferior cerebellar artery (PICA). The other two patients had a ruptured aneurysm of the superior cerebellar artery, and a dissceting aneurysm of the vertebral artery, respectively. Of the 14 patients with SAH, intraventricular hematoma was observed in seven patients, intracerebellar hematoma in three, and subdural hematoma in two. All three patients with unruptured aneurysms had PICA aneurysms. Individual patient data are shown in Table 2.
Table 2
Surgical and intraoperative data
|
Location of aneurysm
|
Size of aneurysm in mm
|
Intracranial
hematoma
on CT
|
EVD or LD
|
ASA score
|
Surgery duration, minutes
|
Amount of iv crystalloids, ml
|
Amount of iv colloids, ml
|
1
|
PICA
|
4 x 2
|
SAH,IVH
|
EVD
|
III
|
235
|
4500
|
500
|
2
|
PICA
|
3 x 4
|
SAH, IVH, ICB
|
EVD
|
IV
|
343
|
3560
|
0
|
3
|
PICA
|
4 x 4
|
SAH, SDH
|
-
|
II
|
188
|
4172
|
1500
|
4
|
SCA
|
2 x 5
|
SAH, ICB
|
EVD
|
IV
|
263
|
3546
|
0
|
5
|
PICA
|
7 x 6
|
-
|
EVD
|
III
|
203
|
4068
|
0
|
6
|
PICA
|
5 x 4
|
SAH, IVH, ICB,SDH
|
EVD
|
IV
|
172
|
1433
|
0
|
7
|
PICA
|
6 x 5
|
SAH, IVH
|
LD
|
III
|
92
|
2715
|
500
|
8
|
PICA
|
17 x 14
|
SAH
|
EVD
|
III
|
385
|
3873
|
1000
|
9
|
PICA
|
8 x 5
|
SAH
|
EVD
|
IV
|
431
|
4607
|
0
|
10
|
Vertebral artery dissecting aneurysm
|
5 x 4
|
SAH
|
-
|
II
|
301
|
3565
|
500
|
11
|
PICA
|
3 x 4
|
SAH, IVH
|
EVD
|
IV
|
141
|
1000
|
1000
|
12
|
PICA
|
4 x 3
|
SAH, IVH
|
EVD
|
IV
|
265
|
1500
|
1000
|
13
|
PICA
|
7 x 5
|
SAH
|
EVD
|
III
|
120
|
3861
|
0
|
14
|
Dissection of vertebral artery, PICA aneurysm
|
4 x 3
|
SAH, IVH
|
VP shunt
|
IV
|
119
|
1475
|
0
|
15
|
PICA
|
7x4
|
-
|
-
|
III
|
137
|
2881
|
500
|
16
|
PICA
|
5x3
|
-
|
-
|
II
|
149
|
2792
|
500
|
17
|
2 PICA aneurysms
|
3 x3 & 7x5
|
-
|
-
|
II
|
231
|
4824
|
1500
|
SAH subarachnoid hemorrhage, H&H Hunt and Hess grading, PICA posterior inferior cerebellar artery, SCA superior cerebellar artery, IVH intraventricular hemorrhage, SDH subdural hematoma, ICB intracerebral bleeding, EVD external ventricular drainage, LD lumbar drainage, VAE venous air embolism
Preoperative digital subtraction angiography identified a single aneurysm in 16/17 patients, while in one patient, two PICA aneurysms on the same side were detected and both of them were clipped (patient 17). The size of the aneurysms is also shown in Table 2 (median size of the largest diameter was 5 mm, ranging from 3 to 17 mm). In two patients, dissections of the vertebral artery were evident.
Six patients with SAH required intubation and mechanical ventilation before performing the angiography. Of the patients with SAH, eleven developed an acute hydrocephalus (placement of ventricular drainages was necessary in 10 patients, and lumbar drainage in one patient). A ventriculoperitoneal shunt had been placed in one instance with a previous SAH.
The scores of the American Society of Anesthesiologists (ASA) Physical Status Classification System were distributed as follows: IV in 7 patients, III in 6 patients, and II in 4 patients (see also Table 2).
Intraoperative course
The median duration of surgery was 203 minutes, ranging from 92 to 431 minutes. On average, patients received 3.198 ml of crystalloid fluids during the procedure. Colloid fluids were administered in 10 patients, while blood transfusion was required in only one instance.
During surgery, there was a rupture of the aneurysm in two patients (both of them had presented with SAH), which was successfully controlled in both instances.
Adenosine was administered intraoperatively in 4 patients to induce arterial hypotension (without relevant complications).
Incidence and severity of VAE
VAE was detected in 4 patients (23.5%) during intraoperative monitoring (Table 3). The severity of VAE (according to the Tübingen grading scale [23]) was classified as grade 2 in 2 patients, and grade 3 and 4 in one patient, respectively. VAE was associated with a mild decrease of EtCO2 levels in 3 patients, by 2, 3 and 5 mmHg, respectively. In two patients, a significant decrease in systolic blood pressure of 20 and 40 mmHg was observed, respectively, which was successfully corrected using catecholamines and fluids. The source of the VAE was identified by the surgeon within the surgical site in all patients, and appropriate measures were implemented to ensure its proper control. The surgical procedure proceeded as planned in all instances.
Table 3
Occurrence of venous air embolism in 4 patients during surgery
Patient no.
|
Grade of VAE
|
Decrease in EtCO2
|
Blood pressure decrease
|
Air aspiration from the iv central line
|
Complications
related to VAE
|
9
|
2
|
3 mmHg
|
none
|
no
|
none
|
10
|
2
|
2 mmHg
|
none
|
yes
|
none
|
14
|
4
|
none
|
40 mmHg
|
no
|
none
|
17
|
3
|
5
|
20 mmHg
|
yes
|
none
|
EtCO2 End-tidal CO2
iv, intravenous
Postoperative CT scans did not reveal any complications related to VAE in the four patients.
Postoperative course und follow-up
In all patients the surgery was completed successfully. There were no intraoperative complications apart from VAE. The median time of hospital stay was 27 days, ranging from 9 to 90 days, which coincided with the median time of stay in the ICU (26 days, ranging from 1 to 90 days; see Table 4. Six patients developed cerebral vasospasms within the first three weeks post-surgery and were treated with a protocol raising systolic arterial pressure and repeated intra-arterial vasospasmolysis using nimodipine.
Table 4
Postoperative course and follow-up
|
Duration of hospital stay (days)
|
Duration of ICU stay (days)
|
Occurrence of vasospasm
|
Cerebral infarction
|
Other complications
|
Tracheostomy at discharge
|
VP shunt
|
Last follow up (months)
|
Barthel-Index
|
1
|
70
|
66
|
yes
|
no
|
Pneumonia
|
no
|
no
|
103
|
100
|
2
|
22
|
21
|
no
|
no
|
Pneumonia
|
yes
|
no
|
-
|
-
|
3
|
50
|
24
|
VA.
|
no
|
Pneumonia
|
no
|
no
|
87
|
35
|
4
|
39
|
39
|
no
|
no
|
Pneumonia, VTE
|
yes
|
no
|
6
|
80
|
5
|
20
|
20
|
no
|
no
|
-
|
no
|
yes
|
17
|
65
|
6
|
23
|
23
|
VA and ACI right
|
Media infarction and cerebellar
|
Pneumonia, hemiparesis, aphasia
|
no
|
no
|
Death
|
-
|
7
|
25
|
21
|
no
|
no
|
-
|
no
|
yes
|
3
|
100
|
8
|
46
|
46
|
no
|
no
|
Pneumonia
|
yes
|
yes
|
38
|
85
|
9
|
51
|
50
|
VA
|
Cerebellar
|
Spastic tetraparesis
|
yes
|
yes
|
8
|
10
|
10
|
31
|
31
|
VA
|
Cerebellar
|
Rectal bleeding
|
no
|
no
|
10
|
90
|
11
|
90
|
90
|
no
|
no
|
Pneumonia, pleural effusion
|
yes
|
yes
|
Death
|
-
|
12
|
30
|
30
|
no
|
Cerebellar
|
Brain edema, Pneumonia, pleural effusion, spastic tetraparesis
|
yes
|
yes
|
46
|
10
|
13
|
27
|
27
|
VA and ACI
|
Cerebellar and temporal
|
Pneumonia
|
yes
|
no
|
58
|
90
|
14
|
26
|
26
|
|
Cerebellar
|
Pneumonia
|
yes
|
already have
|
10
|
80
|
15
|
10
|
1
|
-
|
no
|
no
|
no
|
no
|
4
|
100
|
16
|
9
|
1
|
-
|
no
|
no
|
no
|
no
|
46
|
100
|
17
|
21
|
19
|
-
|
Cerebellar
|
no
|
no
|
no
|
4
|
60
|
VA= vertebral artery, ACI= Internal carotid artery
Three patients had cerebral infarctions related to vasospasm (patients 6, 9 and 13), whereas two other patients developed cerebral infarctions associated with vertebral artery dissection in addition to vasospasm (patients 10 and 14), while two patients had surgery-related cerebral infarction (patients 12 and 17). Postoperative angiography confirmed complete occlusion of the aneurysms, but in two patients compromised parent PICA flow was noted (patients 12 and 17).
Ten patients developed pneumonia during ICU stay but were successfully treated with antibiotics. Additionally, one patient developed lower extremity thrombosis. Out of 14 patients presenting with SAH, 8 underwent tracheostomy during the postoperative period in the ICU. One patient died during ICU stay due to severe respiratory failure, and another one passed away during the early phase of the rehabilitation due to severe pneumonia.
Six patients required ventriculoperitoneal shunts. All patients were referred to rehabilitation for further treatment.
Follow-up information was available in 14 of the 15 surviving patients. The median follow-up duration was 13.5 months (range 3-103 months). The Barthel index 24 of the individual patients at the time of the last follow-up is shown in Table 4. Eleven patients had a Barthel index between 60 and 100, indicating partially or completely independent functional outcome.