- Email: [email protected]
Long-term follow-up of disability among patients with posterior inferior cerebellar artery aneurysm
Journal of Clinical Neuroscience 17 (2010) 980–983
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Clinical Study
Long-term follow-up of disability among patients with posterior inferior cerebellar artery aneurysm Ali Nourbakhsh, Kristopher M. Katira, Christina Notarianni, Prasad Vannemreddy, Bharat Guthikonda, Anil Nanda * Department of Neurosurgery, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130, USA
a r t i c l e
i n f o
Article history: Received 21 July 2009 Accepted 25 October 2009
Keywords: Aneurysm Disability Modified Rankin Scale Posterior inferior cerebellar artery
a b s t r a c t We retrospectively analyzed long-term follow-up data for 15 patients after treatment for posterior inferior cerebellar artery (PICA) aneurysm, particularly in relation to disability as assessed using the Modified Rankin Scale (MRS) score. Patients had a mean follow-up of 38 months. At follow-up, 53% of patients, those with an MRS score of 63, were able to lead an independent life, despite minor deficits. Patients with larger aneurysms may be more susceptible to lower cranial nerve palsies. Published by Elsevier Ltd.
1. Introduction
2. Materials and methods
Posterior inferior cerebellar artery (PICA) aneurysms are uncommon, accounting for only 0.5% to 3% of all intracranial aneurysms.1 Of the major cerebral arteries, the PICA has the most complex and variable course,2 with its origin varying from below the foramen magnum to the vertebrobasilar junction.3 The course of the artery may be divided into five segments based on its relationship to the adjacent structures.4 The considerable variation in the origin of the PICA contributes to the difficulty in treating PICA aneurysms. Therefore, meticulous anatomic evaluation is important for successful surgical or endovascular treatment.5 Several case series and literature reviews have been published on the topic of ruptured PICA aneurysms. Most patients present with subarachnoid hemorrhage, and most aneurysms are small (<10 mm).6–8 Coert et al.,9 Pandey et al.,10 Peluso et al.11 and Horowitz et al.12 have reported the results of various treatment approaches, with variable results. In these studies, the Glasgow Outcome Scale (GOS) score was most commonly used as the outcome indicator. The purpose of the present study was to retrospectively analyze long-term follow-up data for patients with PICA aneurysm after surgical or endovascular treatment, with special respect to disability. We assessed disability using the Modified Rankin Scale (MRS), which is used to measure the extent of disability, ability to carry out the activities of daily living, and the level of independence in patients with cerebrovascular disease.
Between 1999 and 2009, 21 patients with a single PICA aneurysm were referred to our institution, 15 of whom had more than 6 months of follow-up. An institutional review board-approved retrospective review of the medical charts and imaging studies from these 15 patients was conducted. Data on age; sex; medical history; aneurysm size and pathological type; presence of subarachnoid hemorrhage, infarction and hydrocephalus; and average hospital stay were obtained. Follow-up was either via a visit to the clinic or a phone interview. MRS scores of 0 to 3 were considered to indicate independence, and scores of 4 and 5 to indicate dependency. Correlations were evaluated using the v2 test and Fisher’s exact test. Means were compared using Student’s t-test. All statistical analyses were done using SPSS (version 15; SPSS Inc., Chicago, IL, USA).
* Corresponding author. Tel.: +1 318 675 6404; fax: +1 318 675 4615. E-mail address: [email protected] (A. Nanda). 0967-5868/$ - see front matter Published by Elsevier Ltd. doi:10.1016/j.jocn.2009.10.041
3. Results Fourteen out of 15 of our patients were female (Table 1). The average age was 53 years. The most common medical problem was hypertension (47%), followed by coronary artery disease (13%) and hyperlipidemia (13%). Twenty percent of our patients were smokers. The average Hunt and Hess (H&H) score was 2 at the time of presentation to the hospital, and the mean size of the aneurysm was 5.6 mm. Twelve patients (80%) presented with subarachnoid hemorrhage and nine aneurysms were located proximally. Three patients were treated with embolization, and the rest underwent surgical clipping of the aneurysm. The most common
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A. Nourbakhsh et al. / Journal of Clinical Neuroscience 17 (2010) 980–983 Table 1 Summary of characteristics of patients with posterior inferior cerebellar artery aneurysm Patient no.
Follow-up
MRS at followup
36
Bedridden, speech difficulties, died in a nursing home (3 yrs)
4
+
ND
2
Clipping
+
ND
9 (proximal)
Clipping
+
2
3 (proximal)
Clipping
+
+
2
7 (proximal)
Embolization
+
+
2 2
5 (proximal) ND (proximal)
Embolization Clipping
+
3
15 (proximal)
Clipping
+
4 1
2 (distal) 8 (proximal)
Clipping Clipping
+
2
ND (proximal)
Clipping
+
43
HT, CAD, concomitant PCoA aneurysm HT, asthma
3
ND (distal)
Clipping
+
51 70
HL HT, HL, stroke
2 3
2.5 (proximal) 9 (distal)
Embolization Clipping
+ +
Rebleeding after discharge from hospital, bilateral paraparesis, comprehension difficulties despite normal hearing, H/A (5 yrs) VP shunt, H/A, ataxia, dysphagia (10 yrs) Dysphagia, hoarseness, H/A, diplopia (6 yrs) VP shunt with 2 revisions, diplopia (3 yrs) Ataxia (not able to walk), poor vision, VP shunt (1.5 yrs) H/A, paraparesis (2 yrs) H/A, dysphagia, comprehension difficulties despite normal hearing (10 yrs) Hemiparesis, diplopia, speech difficulties, ataxia (wheelchair-bound), in nursing home (8 yrs) VP shunt (1 year) Dysphagia, meningocoele (9 months) 2 months later, PCoA aneurysm was clipped (10 months) Dysphagia, H/A, VP shunt with 1 revision (26 months) H/A (8 months) VP shunt
Sex
Age (yrs)
Medical history
H&H score
Aneurysm size (mm)
Treatment
1
F
54
Neurosurgical resection and radiation for meningioma; poor vision and balance; seizure; smoker
0
25 (proximal)
Clipping
2
F
40
2
ND
Clipping
3
F
75
2
ND
4
F
51
1
5
M
30
6
F
57
7 8
F F
48 37
9
F
48
10 11
F F
76 58
12
F
52
13
F
14 15
F F
HT, CAD, H/A
HT, smoker, concomitant MCA aneurysm Mitral valve prolapse
HT, concomitant PCoA aneurysm
HT, smoker
SAH
VS
Infarct.
Hospital stay (days)
+
+ (SCA territory)
+ (left cerebellum) + (left MCA territory) + (MCA territory)
HC
+
13 46
+
34
+
7 6
+ (frontoparietal)
+
ND
90 3
+
12
+ (left cerebellum)
ND
+
13 23
+
4 2 2 4
2 1
4
4 0 3
2 1 ND
In the ‘‘Follow-up” column, durations in parentheses are the time after diagnosis of the aneurysm that follow-up was performed. ACA = anterior cerebral artery, CAD = coronary artery disease, F = female, H&H score = Hunt and Hess score, H/A = headache, HC = hydrocephalus, HL = hyperlipidemia, HT = hypertension, ICA = internal carotid artery, Infarct. = infarction, M = male, MCA = middle cerebral artery, MRS = Modified Rankin Scale, ND = not determined, PCA = posterior cerebral artery, PCoA = posterior communicating artery, SAH = subarachnoid hemorrhage, SCA = superior cerebellar artery, VP = ventriculoperitoneal, VS = vasospasm, years = yrs.
approach to the proximal PICA was far lateral occipital or transcondylar, whereas suboccipital craniotomy was used for the distal PICA. In the course of the hospital stay, four patients (27%) experienced vasospasm, and CT scans showed that six patients (40%) had infarcts. Six patients (40%) required a ventriculoperitoneal shunt for hydrocephalus. The average hospital stay was 25 days, and the mean MRS score at the time of follow-up was 2. Six patients (40%) required a ventriculoperitoneal shunt for hydrocephalus. Three patients had concomitant aneurysms of the posterior communicating artery and middle cerebral artery. The mean follow-up period was 38 months, and one patient was lost to follow-up. Fifty-three percent of patients had an MRS score of 3 or less, which means that they were able to lead an independent life. Patients with high H&H scores were more likely to have experienced hydrocephalus than patients with lower scores (p = 0.04). There was no significant difference in the mean MRS scores of patients who had been treated with surgical clipping (2.6) and those treated with embolization (2.3) (p = 0.8). Seven (47%) patients complained of headache, six patients (40%) had difficulty walking due to ataxia or paraparesis, and five (33%)
had dysphagia. Other complaints included diplopia (two patients), speech difficulties (two patients) and comprehension difficulties despite normal hearing (two patients). Five patients required tracheostomy. In one patient who suffered aspiration pneumonia (case 13), a sputum culture was positive for Klebsiella pneumoniae and Candida albicans. The patient was treated with ciprofloxacin, piperacillin, tazobactam, and fluconazole. There was no significant difference between the patients with and without lower cranial nerve (LCN) palsies in terms of mean H&H score (p = 0.16), age (p = 0.13), incidence of vasospasm or incidence of hydrocephalus. The mean sizes of the aneurysms in these 2 groups were 11.6 mm and 4.5 mm, respectively (p = 0.056).
4. Discussion More than 80% of PICA aneurysms arise from where the PICA originates from the vertebral artery.7 The mean age of patients presenting with PICA aneurysm has been variously reported to be 4513 and 51 years.3 In the present series, the mean age of patients presenting with PICA aneurysm was higher: 54 years. In a series of 13
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A. Nourbakhsh et al. / Journal of Clinical Neuroscience 17 (2010) 980–983
patients, Liew et al. found that 77% presented after acute subarachnoid hemorrhage, and eight out of ten (80%) operated patients needed cerebrospinal fluid shunting for hydrocephalus.14 In our series, 40% of patients (half of the patients who presented with subarachnoid hemorrhage) needed ventriculoperitoneal shunting. Compared with other intracranial aneurysms, ruptured PICA aneurysms represent a unique subset of intracranial aneurysms, with a higher incidence of intraventricular hemorrhage and secondary hydrocephalus.15 Bleeding from PICA aneurysms usually produces hematoma in the ipsilateral basal cistern, with or without extension into the fourth ventricle.3 This accords with the high incidence of hydrocephalus following subarachnoid hemorrhage in our series. The majority of patients initially had an H&H score of 63, and three (21%) of these patients had poor outcomes (MRS scores of 63). In Yamaura’s series of 90 PICA aneurysms, three patients developed sixth cranial nerve palsy, and eight patients developed ninth and tenth cranial nerve palsies.16 In the study by Andoh et al. on 42 cases of PICA aneurysm, the focus was mostly on the incidence of ninth and tenth cranial nerve palsies (9.5%), with improvement noted in all cases.17 Out of 38 patients with PICA aneurysm who underwent surgery, Horowitz et al. found that 37% had persistent problems at a 1-year follow-up, mostly due to LCN dysfunction.12 Coert et al. studied 49 posterior circulation fusiform aneurysms, including 21 PICA aneurysms, using the GOS score for evaluation over a mean follow-up period of 33 months.9 Overall long-term outcome was good (GOS scores of 4 or 5) in 59% of patients, poor (GOS scores of 2 or 3) in 16%, and fatal (GOS score of 1) in 24%. Univariate analysis showed that poor outcome was predicted by age over 55 years, location at the vertebrobasilar junction, pretreatment H&H score, and incomplete aneurysm obliteration following endovascular treatment.9 In the present study, 53% of patients were able to lead an independent life, although they might not have been able to carry out all activities they were previously capable of. The relatively high level of disability in our series compared with that observed in some previous studies may have occurred because our patients were older and the period of follow-up was longer than in previous studies. At the time of follow-up, the average age of our patients was 55 years (range 33–85 years). The most common long-term complications of PICA aneurysm rupture or surgical intervention for PICA aneurysm include ataxia, motor function deficit, diplopia and dysphagia. Many of our patients (62%) complained of memory problems during long-term follow-up, but because of the high average age of our patients, the symptoms could not be attributed solely to the PICA aneurysm. In the posterior fossa, arterial distributions vary greatly. Vomiting, dizziness and ataxia are common symptoms arising from the occlusion of a single cerebellar artery. The amount of collateral circulation determines the extent of recovery and survival after occlusion of a major cerebellar artery.18 PICA aneurysms lie in close proximity to the third to eleventh cranial nerves, the brainstem and the cerebellum. Manipulation of these structures during surgery for PICA aneurysm explains the relatively high postoperative morbidity rates reported in the literature relative to anterior circulation aneurysms.19 The hematoma exerting pressure on the aforementioned neural structures is another cause of long-term neural deficits. This might explain the lack of difference between the outcomes (i.e. MRS scores) of patients who underwent clipping compared with endovascular treatment in our series. As shown in Table 2, there was no significant difference in the clinical features of patients with and without LCN palsies. The mean sizes of the aneurysms were 11.6 mm and 4.5 mm in these groups, respectively (p = 0.05), which might have been the main factor contributing to the resulting palsies. Larger aneurysms impose more pressure on the LCN and produce a larger hematoma mass, which results in higher rates of neuropraxia in the LCN. Surgery can also
Table 2 Comparison of variables for patients with posterior inferior cerebellar artery aneurysm with and without lower cranial nerve palsies Clinical variable
With LCN palsy
Without LCN palsy
p-value
Mean Hunt and Hess score Mean age (yrs) Mean aneurysm size (mm) No. patients with vasospasm No. patients with SAH No. patients with hydrocephalus
1.7 48 11.6 2/9 (22%) 6/9 (67%) 3/9 (33%)
2.5 59 4.5 2/6 (33%) 6/6 (100%) 3/6 (50%)
0.16 0.12 0.05 0.53 0.18 0.62
LCN = lower cranial nerve, SAH = subarachnoid hemorrhage.
exacerbate the extent of nerve injury. More extensive brain retraction is required for clipping large aneurysms during surgery, and more clips are needed for obliteration, both of which may be factors underlying our findings. For the 47% of patients in our series who experienced long-term disability in terms of performing the activities of daily living, a long period of rehabilitation or involvement of social services was imperative. The retrospective nature of our study and the small sample size limit the general applicability of our findings. The MRS evaluates the ability of patients to lead an independent life, and so plays an important role in disability evaluation. However, the ability of patients to perform other tasks, for example the tasks involved in employment, needs to be assessed objectively and might mandate the use of neuropsychiatric tests. Our study provides a basis for future prospective studies to obtain more complete neuropsychiatric disability profiles for these patients. In summary, long-term follow-up of patients with PICA aneurysm showed that the majority of these patients were able to lead an independent life, despite having minor deficits at an average follow-up of 3 years. A long period of rehabilitation and nursing care seems necessary for the remaining patients, due to LCN neuropathy, hydrocephalus and infarction. H&H score and hydrocephalus were the major factors influencing long-term disability in these patients. References 1. Chen CJ, Chen ST. Extracranial distal aneurysm of posterior inferior cerebellar artery. Neuroradiology 1997;39:344–7. 2. Lister JR, Rhoton Jr AL, Matsushima T. Microsurgical anatomy of the posterior inferior cerebellar artery. Neurosurgery 1982;10:170–99. 3. Lewis SB, Chang DJ, Peace DA, et al. Distal posterior inferior cerebellar artery aneurysms: clinical features and management. J Neurosurg 2002;97:756–66. 4. Huang YP, Wolf BS. Angiographic features of fourth ventricle tumors with special reference to the posterior inferior cerebellar artery. AJR Am J Roentgenol 1969;107:543–664. 5. Li XE, Wang YY, Li G, et al. Clinical presentation and treatment of distal posterior inferior cerebellar artery aneurysms: report on 5 cases. Surg Neurol 2008;70:425–31. 6. Anegawa S, Hayashi T, Torigoe R, et al. Aneurysms of the distal posterior inferior cerebellar artery: analysis of 14 aneurysms in 13 cases. No Shinkei Geka 2001; 29:121–9. 7. Hudgins RJ, Day AL, Quisling RG, et al. Aneurysms of the posterior inferior cerebellar artery. A clinical and anatomical analysis. J Neurosurg 1983;58: 381–7. 8. Lemole Jr GM, Henn J, Javedan S, et al. Cerebral revascularization performed using posterior inferior cerebellar artery-posterior inferior cerebellar artery bypass. Report of four cases and literature review. J Neurosurg 2002;97:219–23. 9. Coert BA, Chang SD, Do HM, et al. Surgical and endovascular management of symptomatic posterior circulation fusiform aneurysms. J Neurosurg 2007;106:855–65. 10. Pandey AS, Koebbe C, Rosenwasser RH, et al. Endovascular coil embolization of ruptured and unruptured posterior circulation aneurysms: review of a 10-year experience. Neurosurgery 2007;60:626–36. 11. Peluso JP, van Rooij WJ, Sluzewski M, et al. Posterior inferior cerebellar artery aneurysms: incidence, clinical presentation, and outcome of endovascular treatment. AJNR Am J Neuroradiol 2008;29:86–90. 12. Horowitz M, Kopitnik T, Landreneau F, et al. Posteroinferior cerebellar artery aneurysms: surgical results for 38 patients. Neurosurgery 1998;43:1026–32.
A. Nourbakhsh et al. / Journal of Clinical Neuroscience 17 (2010) 980–983 13. Dernbach PD, Sila CA, Little JR. Giant and multiple aneurysms of the distal posterior inferior cerebellar artery. Neurosurgery 1998;22:309–12. 14. Liew D, Ng PY, Ng I. Surgical management of ruptured and unruptured symptomatic posterior inferior cerebellar artery aneurysms. Br J Neurosurg 2004;18:608–12. 15. Kallmes DF, Lanzino G, Dix JE, et al. Patterns of hemorrhage with ruptured posterior inferior cerebellar artery aneurysms: CT findings in 44 cases. AJR Am J Roentgenol 1997;169:1169–71.
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16. Yamaura A. Diagnosis and treatment of vertebral aneurysms. J Neurosurg 1988;69:345–9. 17. Andoh T, Shirakami S, Nakashima T, et al. Clinical analysis of a series of vertebral aneurysm cases. Neurosurgery 1992;31:987–93. 18. Rhoton Jr AL. The cerebellar arteries. Neurosurgery 2000;47:S29–68. 19. Hillman J, Säveland H, Jakobsson KE, et al. Overall management outcome of ruptured posterior fossa aneurysms. J Neurosurg 1996;85:33–88.
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Clinical Study
Long-term follow-up of disability among patients with posterior inferior cerebellar artery aneurysm Ali Nourbakhsh, Kristopher M. Katira, Christina Notarianni, Prasad Vannemreddy, Bharat Guthikonda, Anil Nanda * Department of Neurosurgery, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130, USA
a r t i c l e
i n f o
Article history: Received 21 July 2009 Accepted 25 October 2009
Keywords: Aneurysm Disability Modified Rankin Scale Posterior inferior cerebellar artery
a b s t r a c t We retrospectively analyzed long-term follow-up data for 15 patients after treatment for posterior inferior cerebellar artery (PICA) aneurysm, particularly in relation to disability as assessed using the Modified Rankin Scale (MRS) score. Patients had a mean follow-up of 38 months. At follow-up, 53% of patients, those with an MRS score of 63, were able to lead an independent life, despite minor deficits. Patients with larger aneurysms may be more susceptible to lower cranial nerve palsies. Published by Elsevier Ltd.
1. Introduction
2. Materials and methods
Posterior inferior cerebellar artery (PICA) aneurysms are uncommon, accounting for only 0.5% to 3% of all intracranial aneurysms.1 Of the major cerebral arteries, the PICA has the most complex and variable course,2 with its origin varying from below the foramen magnum to the vertebrobasilar junction.3 The course of the artery may be divided into five segments based on its relationship to the adjacent structures.4 The considerable variation in the origin of the PICA contributes to the difficulty in treating PICA aneurysms. Therefore, meticulous anatomic evaluation is important for successful surgical or endovascular treatment.5 Several case series and literature reviews have been published on the topic of ruptured PICA aneurysms. Most patients present with subarachnoid hemorrhage, and most aneurysms are small (<10 mm).6–8 Coert et al.,9 Pandey et al.,10 Peluso et al.11 and Horowitz et al.12 have reported the results of various treatment approaches, with variable results. In these studies, the Glasgow Outcome Scale (GOS) score was most commonly used as the outcome indicator. The purpose of the present study was to retrospectively analyze long-term follow-up data for patients with PICA aneurysm after surgical or endovascular treatment, with special respect to disability. We assessed disability using the Modified Rankin Scale (MRS), which is used to measure the extent of disability, ability to carry out the activities of daily living, and the level of independence in patients with cerebrovascular disease.
Between 1999 and 2009, 21 patients with a single PICA aneurysm were referred to our institution, 15 of whom had more than 6 months of follow-up. An institutional review board-approved retrospective review of the medical charts and imaging studies from these 15 patients was conducted. Data on age; sex; medical history; aneurysm size and pathological type; presence of subarachnoid hemorrhage, infarction and hydrocephalus; and average hospital stay were obtained. Follow-up was either via a visit to the clinic or a phone interview. MRS scores of 0 to 3 were considered to indicate independence, and scores of 4 and 5 to indicate dependency. Correlations were evaluated using the v2 test and Fisher’s exact test. Means were compared using Student’s t-test. All statistical analyses were done using SPSS (version 15; SPSS Inc., Chicago, IL, USA).
* Corresponding author. Tel.: +1 318 675 6404; fax: +1 318 675 4615. E-mail address: [email protected] (A. Nanda). 0967-5868/$ - see front matter Published by Elsevier Ltd. doi:10.1016/j.jocn.2009.10.041
3. Results Fourteen out of 15 of our patients were female (Table 1). The average age was 53 years. The most common medical problem was hypertension (47%), followed by coronary artery disease (13%) and hyperlipidemia (13%). Twenty percent of our patients were smokers. The average Hunt and Hess (H&H) score was 2 at the time of presentation to the hospital, and the mean size of the aneurysm was 5.6 mm. Twelve patients (80%) presented with subarachnoid hemorrhage and nine aneurysms were located proximally. Three patients were treated with embolization, and the rest underwent surgical clipping of the aneurysm. The most common
981
A. Nourbakhsh et al. / Journal of Clinical Neuroscience 17 (2010) 980–983 Table 1 Summary of characteristics of patients with posterior inferior cerebellar artery aneurysm Patient no.
Follow-up
MRS at followup
36
Bedridden, speech difficulties, died in a nursing home (3 yrs)
4
+
ND
2
Clipping
+
ND
9 (proximal)
Clipping
+
2
3 (proximal)
Clipping
+
+
2
7 (proximal)
Embolization
+
+
2 2
5 (proximal) ND (proximal)
Embolization Clipping
+
3
15 (proximal)
Clipping
+
4 1
2 (distal) 8 (proximal)
Clipping Clipping
+
2
ND (proximal)
Clipping
+
43
HT, CAD, concomitant PCoA aneurysm HT, asthma
3
ND (distal)
Clipping
+
51 70
HL HT, HL, stroke
2 3
2.5 (proximal) 9 (distal)
Embolization Clipping
+ +
Rebleeding after discharge from hospital, bilateral paraparesis, comprehension difficulties despite normal hearing, H/A (5 yrs) VP shunt, H/A, ataxia, dysphagia (10 yrs) Dysphagia, hoarseness, H/A, diplopia (6 yrs) VP shunt with 2 revisions, diplopia (3 yrs) Ataxia (not able to walk), poor vision, VP shunt (1.5 yrs) H/A, paraparesis (2 yrs) H/A, dysphagia, comprehension difficulties despite normal hearing (10 yrs) Hemiparesis, diplopia, speech difficulties, ataxia (wheelchair-bound), in nursing home (8 yrs) VP shunt (1 year) Dysphagia, meningocoele (9 months) 2 months later, PCoA aneurysm was clipped (10 months) Dysphagia, H/A, VP shunt with 1 revision (26 months) H/A (8 months) VP shunt
Sex
Age (yrs)
Medical history
H&H score
Aneurysm size (mm)
Treatment
1
F
54
Neurosurgical resection and radiation for meningioma; poor vision and balance; seizure; smoker
0
25 (proximal)
Clipping
2
F
40
2
ND
Clipping
3
F
75
2
ND
4
F
51
1
5
M
30
6
F
57
7 8
F F
48 37
9
F
48
10 11
F F
76 58
12
F
52
13
F
14 15
F F
HT, CAD, H/A
HT, smoker, concomitant MCA aneurysm Mitral valve prolapse
HT, concomitant PCoA aneurysm
HT, smoker
SAH
VS
Infarct.
Hospital stay (days)
+
+ (SCA territory)
+ (left cerebellum) + (left MCA territory) + (MCA territory)
HC
+
13 46
+
34
+
7 6
+ (frontoparietal)
+
ND
90 3
+
12
+ (left cerebellum)
ND
+
13 23
+
4 2 2 4
2 1
4
4 0 3
2 1 ND
In the ‘‘Follow-up” column, durations in parentheses are the time after diagnosis of the aneurysm that follow-up was performed. ACA = anterior cerebral artery, CAD = coronary artery disease, F = female, H&H score = Hunt and Hess score, H/A = headache, HC = hydrocephalus, HL = hyperlipidemia, HT = hypertension, ICA = internal carotid artery, Infarct. = infarction, M = male, MCA = middle cerebral artery, MRS = Modified Rankin Scale, ND = not determined, PCA = posterior cerebral artery, PCoA = posterior communicating artery, SAH = subarachnoid hemorrhage, SCA = superior cerebellar artery, VP = ventriculoperitoneal, VS = vasospasm, years = yrs.
approach to the proximal PICA was far lateral occipital or transcondylar, whereas suboccipital craniotomy was used for the distal PICA. In the course of the hospital stay, four patients (27%) experienced vasospasm, and CT scans showed that six patients (40%) had infarcts. Six patients (40%) required a ventriculoperitoneal shunt for hydrocephalus. The average hospital stay was 25 days, and the mean MRS score at the time of follow-up was 2. Six patients (40%) required a ventriculoperitoneal shunt for hydrocephalus. Three patients had concomitant aneurysms of the posterior communicating artery and middle cerebral artery. The mean follow-up period was 38 months, and one patient was lost to follow-up. Fifty-three percent of patients had an MRS score of 3 or less, which means that they were able to lead an independent life. Patients with high H&H scores were more likely to have experienced hydrocephalus than patients with lower scores (p = 0.04). There was no significant difference in the mean MRS scores of patients who had been treated with surgical clipping (2.6) and those treated with embolization (2.3) (p = 0.8). Seven (47%) patients complained of headache, six patients (40%) had difficulty walking due to ataxia or paraparesis, and five (33%)
had dysphagia. Other complaints included diplopia (two patients), speech difficulties (two patients) and comprehension difficulties despite normal hearing (two patients). Five patients required tracheostomy. In one patient who suffered aspiration pneumonia (case 13), a sputum culture was positive for Klebsiella pneumoniae and Candida albicans. The patient was treated with ciprofloxacin, piperacillin, tazobactam, and fluconazole. There was no significant difference between the patients with and without lower cranial nerve (LCN) palsies in terms of mean H&H score (p = 0.16), age (p = 0.13), incidence of vasospasm or incidence of hydrocephalus. The mean sizes of the aneurysms in these 2 groups were 11.6 mm and 4.5 mm, respectively (p = 0.056).
4. Discussion More than 80% of PICA aneurysms arise from where the PICA originates from the vertebral artery.7 The mean age of patients presenting with PICA aneurysm has been variously reported to be 4513 and 51 years.3 In the present series, the mean age of patients presenting with PICA aneurysm was higher: 54 years. In a series of 13
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patients, Liew et al. found that 77% presented after acute subarachnoid hemorrhage, and eight out of ten (80%) operated patients needed cerebrospinal fluid shunting for hydrocephalus.14 In our series, 40% of patients (half of the patients who presented with subarachnoid hemorrhage) needed ventriculoperitoneal shunting. Compared with other intracranial aneurysms, ruptured PICA aneurysms represent a unique subset of intracranial aneurysms, with a higher incidence of intraventricular hemorrhage and secondary hydrocephalus.15 Bleeding from PICA aneurysms usually produces hematoma in the ipsilateral basal cistern, with or without extension into the fourth ventricle.3 This accords with the high incidence of hydrocephalus following subarachnoid hemorrhage in our series. The majority of patients initially had an H&H score of 63, and three (21%) of these patients had poor outcomes (MRS scores of 63). In Yamaura’s series of 90 PICA aneurysms, three patients developed sixth cranial nerve palsy, and eight patients developed ninth and tenth cranial nerve palsies.16 In the study by Andoh et al. on 42 cases of PICA aneurysm, the focus was mostly on the incidence of ninth and tenth cranial nerve palsies (9.5%), with improvement noted in all cases.17 Out of 38 patients with PICA aneurysm who underwent surgery, Horowitz et al. found that 37% had persistent problems at a 1-year follow-up, mostly due to LCN dysfunction.12 Coert et al. studied 49 posterior circulation fusiform aneurysms, including 21 PICA aneurysms, using the GOS score for evaluation over a mean follow-up period of 33 months.9 Overall long-term outcome was good (GOS scores of 4 or 5) in 59% of patients, poor (GOS scores of 2 or 3) in 16%, and fatal (GOS score of 1) in 24%. Univariate analysis showed that poor outcome was predicted by age over 55 years, location at the vertebrobasilar junction, pretreatment H&H score, and incomplete aneurysm obliteration following endovascular treatment.9 In the present study, 53% of patients were able to lead an independent life, although they might not have been able to carry out all activities they were previously capable of. The relatively high level of disability in our series compared with that observed in some previous studies may have occurred because our patients were older and the period of follow-up was longer than in previous studies. At the time of follow-up, the average age of our patients was 55 years (range 33–85 years). The most common long-term complications of PICA aneurysm rupture or surgical intervention for PICA aneurysm include ataxia, motor function deficit, diplopia and dysphagia. Many of our patients (62%) complained of memory problems during long-term follow-up, but because of the high average age of our patients, the symptoms could not be attributed solely to the PICA aneurysm. In the posterior fossa, arterial distributions vary greatly. Vomiting, dizziness and ataxia are common symptoms arising from the occlusion of a single cerebellar artery. The amount of collateral circulation determines the extent of recovery and survival after occlusion of a major cerebellar artery.18 PICA aneurysms lie in close proximity to the third to eleventh cranial nerves, the brainstem and the cerebellum. Manipulation of these structures during surgery for PICA aneurysm explains the relatively high postoperative morbidity rates reported in the literature relative to anterior circulation aneurysms.19 The hematoma exerting pressure on the aforementioned neural structures is another cause of long-term neural deficits. This might explain the lack of difference between the outcomes (i.e. MRS scores) of patients who underwent clipping compared with endovascular treatment in our series. As shown in Table 2, there was no significant difference in the clinical features of patients with and without LCN palsies. The mean sizes of the aneurysms were 11.6 mm and 4.5 mm in these groups, respectively (p = 0.05), which might have been the main factor contributing to the resulting palsies. Larger aneurysms impose more pressure on the LCN and produce a larger hematoma mass, which results in higher rates of neuropraxia in the LCN. Surgery can also
Table 2 Comparison of variables for patients with posterior inferior cerebellar artery aneurysm with and without lower cranial nerve palsies Clinical variable
With LCN palsy
Without LCN palsy
p-value
Mean Hunt and Hess score Mean age (yrs) Mean aneurysm size (mm) No. patients with vasospasm No. patients with SAH No. patients with hydrocephalus
1.7 48 11.6 2/9 (22%) 6/9 (67%) 3/9 (33%)
2.5 59 4.5 2/6 (33%) 6/6 (100%) 3/6 (50%)
0.16 0.12 0.05 0.53 0.18 0.62
LCN = lower cranial nerve, SAH = subarachnoid hemorrhage.
exacerbate the extent of nerve injury. More extensive brain retraction is required for clipping large aneurysms during surgery, and more clips are needed for obliteration, both of which may be factors underlying our findings. For the 47% of patients in our series who experienced long-term disability in terms of performing the activities of daily living, a long period of rehabilitation or involvement of social services was imperative. The retrospective nature of our study and the small sample size limit the general applicability of our findings. The MRS evaluates the ability of patients to lead an independent life, and so plays an important role in disability evaluation. However, the ability of patients to perform other tasks, for example the tasks involved in employment, needs to be assessed objectively and might mandate the use of neuropsychiatric tests. Our study provides a basis for future prospective studies to obtain more complete neuropsychiatric disability profiles for these patients. In summary, long-term follow-up of patients with PICA aneurysm showed that the majority of these patients were able to lead an independent life, despite having minor deficits at an average follow-up of 3 years. A long period of rehabilitation and nursing care seems necessary for the remaining patients, due to LCN neuropathy, hydrocephalus and infarction. H&H score and hydrocephalus were the major factors influencing long-term disability in these patients. References 1. Chen CJ, Chen ST. Extracranial distal aneurysm of posterior inferior cerebellar artery. Neuroradiology 1997;39:344–7. 2. Lister JR, Rhoton Jr AL, Matsushima T. Microsurgical anatomy of the posterior inferior cerebellar artery. Neurosurgery 1982;10:170–99. 3. Lewis SB, Chang DJ, Peace DA, et al. Distal posterior inferior cerebellar artery aneurysms: clinical features and management. J Neurosurg 2002;97:756–66. 4. Huang YP, Wolf BS. Angiographic features of fourth ventricle tumors with special reference to the posterior inferior cerebellar artery. AJR Am J Roentgenol 1969;107:543–664. 5. Li XE, Wang YY, Li G, et al. Clinical presentation and treatment of distal posterior inferior cerebellar artery aneurysms: report on 5 cases. Surg Neurol 2008;70:425–31. 6. Anegawa S, Hayashi T, Torigoe R, et al. Aneurysms of the distal posterior inferior cerebellar artery: analysis of 14 aneurysms in 13 cases. No Shinkei Geka 2001; 29:121–9. 7. Hudgins RJ, Day AL, Quisling RG, et al. Aneurysms of the posterior inferior cerebellar artery. A clinical and anatomical analysis. J Neurosurg 1983;58: 381–7. 8. Lemole Jr GM, Henn J, Javedan S, et al. Cerebral revascularization performed using posterior inferior cerebellar artery-posterior inferior cerebellar artery bypass. Report of four cases and literature review. J Neurosurg 2002;97:219–23. 9. Coert BA, Chang SD, Do HM, et al. Surgical and endovascular management of symptomatic posterior circulation fusiform aneurysms. J Neurosurg 2007;106:855–65. 10. Pandey AS, Koebbe C, Rosenwasser RH, et al. Endovascular coil embolization of ruptured and unruptured posterior circulation aneurysms: review of a 10-year experience. Neurosurgery 2007;60:626–36. 11. Peluso JP, van Rooij WJ, Sluzewski M, et al. Posterior inferior cerebellar artery aneurysms: incidence, clinical presentation, and outcome of endovascular treatment. AJNR Am J Neuroradiol 2008;29:86–90. 12. Horowitz M, Kopitnik T, Landreneau F, et al. Posteroinferior cerebellar artery aneurysms: surgical results for 38 patients. Neurosurgery 1998;43:1026–32.
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