Keiichi Nishimaki

Hyperperfusion Syndrome After Neck Clipping of a Ruptured Aneurysm on a Dolichoectatic Middle Cerebral Artery

A 40-year-old female presented with sudden onset of severe headache and vomiting due to subarachnoid hemorrhage. Angiography demonstrated a saccular aneurysm on a dolichoectatic left middle cerebral artery (MCA) and delayed filling of the MCA. Magnetic resonance imaging showed a partially thrombosed giant aneurysm on the dolichoectatic MCA. An intentionally delayed operation was performed, during which the neck of the aneurysm was successfully clipped. The patient exhibited aphasia 48 hours after surgery. Single-photon emission computed tomography revealed hyperperfusion in the territory of the left MCA. The patients blood pressure was maintained normotensively, and her symptoms gradually improved. She returned to work 1 month after surgery. The saccular aneurysm was formed on the dolichoectatic MCA, presumably due to an abnormal arterial wall and hemodynamic stress. The preoperative hypoperfusion might have been caused not only by the giant aneurysm, but also to some degree by the dolichoectatic MCA. After neck clipping, the increase in blood flow might have caused hyperperfusion.

Cerebral haemodynamic changes after endovascular treatment of arteriovenous malformations: Evaluation by single-photon emission CT

SummaryCerebral haemodynamic changes in 17 patients with cerebral arteriovenous malformations (AVMs), who showed hypoperfusion on single-photon emission computed tomography (SPECT) before endovascular treatment, were studied after embolization. Nine of them had non-haemorrhagic clinical manifestations and the other eight had a history of intracranial haemorrhage. Obliteration of AVMs was nearly total in six patients and partial in eleven.New low density lesions on X-ray computed tomography (CT) developed in 3 of 6 patients after nearly total obliteration and one of 11 patients after partial obliteration.The first SPECT after embolization showed diminished hypoperfusion in 11 of 13 patients without new low density lesions and one of 4 patients with new low density lesions. Diminution of hypoperfusion was seen even in two patients who underwent SPECT study immediately after the embolization. Cerebral circulation was improved in five of eight patients with low density lesions before embolization and in nine of eleven patients after partial obliteration. Hypoperfused state in the haemorrhagic group tended to remain unchanged compared with that in the non-haemorrhagic group. The hypoperfused area was expanded after embolization in three patients with new cerebral infarction.It is important for improvement of cerebral circulation to reduce the shunt flow without causing new infarction due to the embolization itself. In one of two patients who had a hyperperfused area surrounding the AVM after embolization, an unexpected and abnormal degree of brain swelling and haemorrhage occurred at the end of the surgery 20 days after the embolization. In the other patient, total extirpation was successfully performed after confirming disappearance of hyperperfusion in the follow-up SPECT.SPECT allows repeated measurement of the cerebral blood flow pattern easily and safely, and is useful for AVM management.

Contralateral hearing loss after acoustic neuroma surgery

A 74-year-old man suffered contralateral hearing loss after left acoustic neuroma surgery. Steroid therapy was administered, but no improvement was observed. Contralateral hearing loss is an extremely rare and distressing complication that can occur following acoustic neuroma surgery. Although the mechanism of this rare phenomenon remains unclear, we speculate that in this patient the loss of cerebrospinal fluid or internal auditory artery thrombosis may be involved.

Primary cystic germinoma originating from the midbrain

A primary intracranial germinoma that involves the midbrain is rare. We describe an unusual case of primary cystic germinoma originating from the midbrain. A 29-year-old man presented with diplopia, and his MRI showed a cystic, ring-like enhanced lesion in the thalamo-mesencephalic junction. Open biopsy was performed and the diagnosis of germinoma was based upon the histopathological findings. Following chemotherapy and radiotherapy, the symptoms improved and the tumor disappeared. We propose that primary intracranial germinoma should be included in the differential diagnosis of midbrain tumors, because early diagnosis and appropriate treatment for midbrain germinoma improves clinical outcome.

Onyx removal after embolization of a superior sagittal sinus dural arteriovenous fistula involving scalp artery.

Background: Most dural arteriovenous fistula (DAVF) in superior sagittal sinus (SSS) requires multimodal treatment. Onyx embolization is useful for DAVF; however, scalp artery embolization has cast extrusion risk. Case Description: A 59-year-old male presented with involuntary movements of both legs and progressive dementia. Cerebral angiography demonstrated the DAVF in the SSS fed by bilateral superficial temporal, occipital, and middle meningeal arteries. The posterior SSS was thrombosed, and the main drainers were cortical veins. Combined treatment with transarterial embolization using Onyx and transvenous embolization using coils was performed. Although symptoms were improved, a small DAVF remained. Two months later, Onyx cast extrusion through the scalp was observed, requiring removal and debridement because of infection at the extrusion sites. Surgery for the residual DAVF would be difficult because of scalp condition; therefore, an additional endovascular treatment was conducted, completely occluding DAVF. Conclusion: Onyx embolization is useful for DAVF; however, scalp artery embolization has cast extrusion risk. Therefore, scalp infection should be considered because it may preclude additional surgical procedures.

Postprandial Hypotension and Coma Following Subarachnoid Hemorrhage in a Patient with Parkinson's Disease

A 79-year-old woman with a history of Parkinsons disease was admitted to our hospital because of a subarachnoid hemorrhage. She underwent clipping the next day. On postoperative days 7-9, she exhibited hypotension and disturbance of consciousness after each meal. The administration of midodrine relieved the hypotension, and postprandial coma was no longer observed. In this case, the autonomic dysfunction in Parkinsons disease and impairment of cerebral autoregulation during cerebral vasospasm may have been involved in the postprandial hypotension (PPH) and coma. PPH occurs not only in patients with Parkinsons disease but also in elderly patients, particularly those with diabetes or hypertension. Therefore, PPH must be considered in the management of cerebral vasospasm following subarachnoid hemorrhage.