Angiographic Analysis of Natural Anastomoses between the Posterior and Anterior Cerebral Arteries in Moyamoya Disease and Syndrome

BACKGROUND AND PURPOSE

Moyamoya disease is a chronic neurovascular steno-occlusive disease of the internal carotid artery and its main branches, associated with the development of compensatory vascular collaterals. Literature is lacking about the precise description of these compensatory vascular systems. Usually, the posterior circulation is less affected, and its vascular flow could compensate the hypoperfusion of the ICA territories. The aim of this study was to describe these natural connections between the posterior cerebral artery and the anterior cerebral artery necessary to compensate the lack of perfusion of the anterior cerebral artery territories in the Moyamoya population.

MATERIALS AND METHODS

All patients treated for Moyamoya disease from 2004 to 2018 in 4 neurosurgical centers with available cerebral digital subtraction angiography were included. Forty patients (80 hemispheres) with the diagnosis of Moyamoya disease were evaluated. The presence of anastomoses between the posterior cerebral artery and the anterior cerebral artery was found in 31 hemispheres (38.7%).

RESULTS

Among these 31 hemispheres presenting with posterior cerebral artery-anterior cerebral artery anastomoses, the most frequently encountered collaterals were branches from the posterior callosal artery (20%) and the posterior choroidal arteries (20%). Another possible connection found was pio-pial anastomosis between cortical branches of the posterior cerebral artery and the anterior cerebral artery (15%). We also proposed a 4-grade classification based on the competence of these anastomoses to supply retrogradely the territories of the anterior cerebral artery.

CONCLUSIONS

We found 3 different types of anastomoses between the anterior and posterior circulations, with different abilities to compensate the anterior circulation. Their development depends on the perfusion needs of the territories of the anterior cerebral artery and can provide the retrograde refilling of the anterior cerebral artery branches.

Embolization as one modality in a combined strategy for the management of cerebral arteriovenous malformations

SUMMARY

We attempted to assess clinical results of management of cerebral arteriovenous malformation using a combination of endovascular, surgical and radiotherapeutic approaches. We retrospectively reviewed the angiographic and clinical data on prospectively collected consecutive patients treated by embolization from 1994 to 2004. The general philosophy was to attempt treatment by a combination of approaches only when an angiographic cure was likely or at least possible. The clinical outcome was assessed according to the modified Rankin scale. Although 404 patients were collected, complete files and follow-ups are available for 227 or 56% only. Most patients presented with hemorrhages (53%) or seizures (23%). The final management consisted in embolization alone in 34%, embolization followed by surgery in 47%, embolization and radiotherapy in 16%, and embolization, surgery and radiotherapy in 3% of patients. The embolization procedure itself could lead to an angiographic cure in only 16% of patients. When the management strategy could be completed, the cure rate increased to 66%. Complications of embolization occurred in 22.6% of patients. Overall clinical outcome was excellent (Rankin 0) in 43%, good (Rankin 1) in 38%, fair (Rankin 2) in 10%, poor (Rankin 3-5) in 2%, and the death rate was 7%. A combined strategy initially designed to provide angiographic cures cannot be completed in a significant number of patients; the total morbidity of treatment remains significant. There is no scientific evidence that cerebral arteriovenous malformations should be treated, and no clinical trial to prove that one approach is better than the other. Various treatment protocols have been proposed on empirical grounds. Small lesions can often be eradicated, with surgery when lesions are superficial, or with radiation therapy for deeper ones. There has been little controversy regarding therapeutic indications in these patients (1). The management of larger AVMs, sometimes in more eloquent locations, is much more difficult and controversial (2-4). Endovascular approaches have initially been developed to meet this challenge (5,6). It became quickly evident that embolization alone would rarely suffice to completely cure these lesions. The philosophy behind combined approaches is founded on 2 opinions: 1) There is no proven value of partial embolization, not even "partial benefits", and treatment should aim at an angiographic cure (7) and 2) By appropriately tailoring all available tools to each situation, such a cure could be reached with minimum or reasonable risks. We have used such a combined strategy for more than a decade now. Endovascular techniques and materials have evolved, and it is perhaps possible today to reach a cure by embolization alone in a larger proportion of patients than before (8). Aggressive embolizations, aiming for an endovascular cure, even sometimes in large lesions, have recently been promoted for their power or criticized for their risks (9). But before evaluating the advantages and inconveniences of new treatments, it may be wise to review the results we could achieve with a conventional approach combining endovascular, surgical and radiotherapeutic techniques.

Patterns of music agnosia associated with middle cerebral artery infarcts

The objective of the study is to evaluate if the rupture of an aneurysm located on the middle cerebral artery (MCA) results in disorders of music recognition. To this aim, 20 patients having undergone brain surgery for the clipping of a unilateral left (LBS), right (RBS) or bilateral (BBS) aneurysm(s) of the MCA and 20 neurologically intact control subjects (NC) were evaluated with a series of tests assessing most of the abilities involved in music recognition. In general, the study shows that a ruptured aneurysm on the MCA that is repaired by brain surgery is very likely to produce deficits in the auditory processing of music. The incidence of such a deficit was not only very high but also selective. The results show that the LBS group was more impaired than the NC group in all three tasks involving musical long-term memory. The study also uncovered two new cases of apperceptive agnosia for music. These two patients (N.R. and R.C.) were diagnosed as such because both exhibit a clear deficit in each of the three music memory tasks and both are impaired in all discrimination tests involving musical perception. Interestingly, the lesions overlap in the right superior temporal lobe and in the right insula, making the two new cases very similar to an earlier case report. Altogether, the results are also consistent with the view that apperceptive agnosia results from damage to right hemispheric structures while associative agnosia results from damage to the left hemisphere.

Endovascular treatment of acutely ruptured and unruptured aneurysms of the basilar bifurcation

The surgical treatment of basilar bifurcation aneurysms is difficult and the need for an alternative approach is frequently stated. To assess the efficacy and safety of endovascular treatment of aneurysms located at the basilar bifurcation, the authors prospectively studied angiographic results, clinical results, and complications in 31 patients treated with Guglielmi detachable coils (GDCs). Patients treated acutely after subarachnoid hemorrhage (SAH) were graded according to the Hunt and Hess classification and clinical outcome was determined at 1- and 6-month intervals according to the Glasgow Outcome Scale (GOS). There were 18 women and 13 men, ranging in age from 34 to 67 years (mean age 48 years). Twenty-three were treated acutely after SAH. Clinical Hunt and Hess grades at presentation were as follows: Grade I, six patients; Grade II, three; Grade III, 11; Grade IV, two; and Grade V, one. The GOS score for the group of patients treated acutely was: GOS I, 18 patients; GOS II, III, and IV, one patient each; and GOS V, two patients. There were seven technical complications in this group, most often asymptomatic, but one patient died after aneurysm rupture during treatment and one had residual diplopia at 4 months. Eight patients were treated for incidental basilar bifurcation aneurysms. One technical complication with no neurological deficit occurred in this group of patients with incidental aneurysms. Immediate angiographic results were considered to be satisfactory in 94% of patients, with complete obliteration in 42% and residual neck and dog ears in 52%. There was no bleeding episode after treatment during clinical follow-up periods ranging from 3 to 42 months (mean 15.5 months in 29 surviving patients). Angiographic results were available for 27 patients at 6 months and were as follows: 30% of the lesions were completely obliterated, 59% presented some residual neck, and 11% showed some opacification of the aneurysm sac. During the follow-up period of up to 42 months, a total of seven recurrences were noted, necessitating retreatment with GDCs in five patients. Endovascular treatment of basilar bifurcation aneurysms prevented rebleeding and could be performed without clinically significant complications in 94% of patients. Clinical results after SAH compared favorably with surgical series. Morphological results appear less satisfactory, and long-term angiographic follow-up review is mandatory to detect recurrences.

[Hypothalamic astrocytoma presenting as obesity with hypogonadism]

We report herein a case of a 30 year old male patient who consulted for a long standing obesity since childhood. Clinical examination reveals the presence of hypogonadism and gynecomastia without galactorrhea. Endocrine assessment showed an hypogonadotrophic hypogonadism with a moderate insufficiency of the adrenocortical axis. Neuro-ophthalmological examination disclosed an inferior bitemporal quadranopsia. MRI showed an extra-axial suprasellar mass, lightly hypointense in T1 and hyperintense in T2. After craniotomy and conservative biopsy, pathological examination of the tumor showed regular cells surrounded with collagen and reticulin marked with immunoperoxidase against S100 protein and GFAP (glial fibrinolytic acidic protein) strongly suggesting the diagnosis of juvenile pilocytic astrocytoma.