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  • Author or Editor: Volker Seifert x
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Volker Seifert and Dietmar Stolke

Aneurysms of the basilar trunk and vertebrobasilar junction represent an exceptional challenge to the neurosurgeon. Surgical access to these deep and confined lesions is hampered by the direct proximity of highly vulnerable neural structures such as the brainstem and cranial nerves, as well as by the structure of the petrous bone, which blocks direct surgical approach to these aneurysms. A number of surgical tactics consisting of different supra- and infratentorial approaches have been applied over the years to gain access to these treacherous lesions. Only recently have lateral approaches, such as the anterior transpetrosal, the retrolabyrinthine-transsigmoidal, and the combined supra/infratentorial-posterior transpetrosal approaches, directed through parts of the petrous bone, been reported for surgery of basilar trunk and vertebrobasilar junction aneurysms. Because detailed reports of direct operative intervention using the transpetrosal route for these rare and difficult lesions are scarce, the authors present their surgical experiences in nine patients with basilar trunk and vertebrobasilar junction aneurysms, in whom they operated via the supra/infratentorial-posterior transpetrosal approach. In eight patients, including one with a giant partially thrombosed basilar trunk aneurysm, direct clipping of the aneurysm via the transpetrosal route was possible. In one patient with a giant vertebrobasilar junction aneurysm, the completely calcified aneurysm sac was resected after occlusion of the vertebral artery. In total, one patient died and another experienced postoperative accentuation of preexisting cranial nerve deficits. Two patients had transient cerebrospinal fluid leakage, and the postoperative course was uneventful in the remaining seven. Postoperative angiography demonstrated complete aneurysm clipping in eight patients and relief of preoperative brainstem compression in the patient with the giant vertebrobasilar junction aneurysm. It is concluded that the supra/infratentorial-posterior transpetrosal approach allows excellent access to the basilar artery trunk and vertebrobasilar junction and can be considered the approach of choice to selected aneurysms located in this area.

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Volker Seifert and Dietmar Stolke

✓ Aneurysms of the basilar trunk and vertebrobasilar junction represent an exceptional challenge to the neurosurgeon. Surgical access to these deep and confined lesions is hampered by the direct proximity of highly vulnerable neural structures such as the brainstem and cranial nerves, as well as by the structure of the petrous bone, which blocks direct surgical approach to these aneurysms. A number of surgical tactics consisting of different supra- and infratentorial approaches have been applied over the years to gain access to these treacherous lesions. Only recently have lateral approaches, such as the anterior transpetrosal, the retrolabyrinthine—transsigmoidal, and the combined supra/infratentorial—posterior transpetrosal approaches, directed through parts of the petrous bone, been reported for surgery of basilar trunk and vertebrobasilar junction aneurysms. Because detailed reports of direct operative intervention using the transpetrosal route for these rare and difficult lesions are scarce, the authors present their surgical experiences in nine patients with basilar trunk and vertebrobasilar junction aneurysms, in whom they operated via the supra/infratentorial—posterior transpetrosal approach. In eight patients, including one with a giant partially thrombosed basilar trunk aneurysm, direct clipping of the aneurysm via the transpetrosal route was possible. In one patient with a giant vertebrobasilar junction aneurysm, the completely calcified aneurysm sac was resected after occlusion of the vertebral artery. In total, one patient died and another experienced postoperative accentuation of preexisting cranial nerve deficits. Two patients had transient cerebrospinal fluid leakage, and the postoperative course was uneventful in the remaining seven. Postoperative angiography demonstrated complete aneurysm clipping in eight patients and relief of preoperative brainstem compression in the patient with the giant vertebrobasilar junction aneurysm. It is concluded that the supra/infratentorial—posterior transpetrosal approach allows excellent access to the basilar artery trunk and vertebrobasilar junction and can be considered the approach of choice to selected aneurysms located in this area.

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Thomas Brinker, Volker Seifert and Dietmar Stolke

✓ The effect of intrathecal fibrinolysis on cerebrospinal fluid (CSF) absorption was investigated after experimental subarachnoid hemorrhage (SAH). In 11 cats, SAH was induced by intracisternal application of 1 to 4 ml of fresh autologous blood. Thirty minutes after the experimental SAH, the CSF outflow resistance was found to be elevated from a median of 77 mm Hg/ml/min (range 41.3 to 109 mm Hg/ml/min) to a median of 580 mm Hg/ml/min (range 104 to 7000 mm Hg/ml/min). A logarithmic relationship could be demonstrated between the volume of subarachnoid blood and the elevation of the CSF outflow resistance. The intrathecal application of 2 mg of recombinant tissue plasminogen activator (rt-PA), which is a fibrinolytic substance suitable for lysis of subarachnoid blood clots in man, resulted in an almost total restoration of CSF absorption after experimental SAH. The CSF outflow resistance after SAH was lowered by application of rt-PA from a median of 1028.05 mm Hg/ml/min (range 394 to 7000 mm Hg/ml/min) to 79 mm Hg/ml/min (range 56.7 to 223 mm Hg/ml/min). It is concluded that the impairment of CSF absorption after SAH may play an important role in the pathogenesis of post-hemorrhagic vasospasm.

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Volker Seifert, Dietmar Stolke, Hubertus M. Mehdorn and Bernd Hoffmann

✓ Within a period of nearly 10 years, from October, 1980, to May, 1990, a total of 68 patients with a cerebral arteriovenous malformation (AVM) were referred to a radiosurgical center in the United States for stereotactic Bragg peak proton beam therapy. Radiosurgery was chosen as an alternative treatment, either because the AVM was considered to be of high surgical risk due to its size and/or location, or because the patient refused surgery. In 63 patients (92.6%), complete clinical and radiological follow-up examinations were available. Clinical and radiological long-term results were correlated to size and to the Spetzler-Martin scale of the AVM. With increasing size or higher grade on the Spetzler-Martin scale, the clinical results of proton beam therapy became progressively worse. Of 37 patients with an AVM between 3 and 6 cm in diameter, only one-third showed amelioration of their clinical symptoms, and two-thirds remained the same or even deteriorated after radiation treatment. The same results apply to patients with very large AVM's, of whom only one-third profited from proton beam therapy. Although 85.7% of the patients in Spetzler-Martin Grades I and II showed postirradiation amelioration of their clinical symptoms, this compares to only 54.2% of the patients in Grade III, and only 24% in Grade IV. In regard to the radiological results of proton beam therapy, complete obliteration during long-term observation was only detectable in 10 patients or 15.9%, which is less than one-sixth of the whole group of 63 patients. All of these obliterated AVM's were smaller than 3 cm. Almost 85% of the patients treated using stereotactic proton beam therapy did not show any angiographic change in the radiological appearance of their AVM. The results reported here indicate that radiosurgery using stereotactic proton beam therapy is ineffective for the treatment of medium- or large-sized AVM's and should not be recommended for patients harboring an AVM larger than 3 cm. If proton beam treatment is contemplated, it should be restricted to AVM's that are less than 3 cm in size and whose location makes them easily accessible only for proton beam therapy.

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Endothelin concentrations in patients with aneurysmal subarachnoid hemorrhage

Correlation with cerebral vasospasm, delayed ischemic neurological deficits, and volume of hematoma

Volker Seifert, Bernd-Michael Löffler, Michael Zimmermann, Sébastiên Roux and Dietmar Stolke

✓ Plasma and cerebrospinal fluid (CSF) concentrations of endothelin (ET)-1, ET-3, and big ET-1 in patients with aneurysmal rupture were measured serially for 2 weeks after the onset of aneurysmal subarachnoid hemorrhage (SAH) and compared with levels of ETs in patients without SAH and the plasma concentrations of ETs in normal volunteers. Big ET-1 was the predominant peptide present in the CSF of SAH patients. The CSF concentrations of big ET-1, ET-1, and ET-3 were significantly higher in older patients than in younger patients. In SAH patients with cerebral vasospasm (CVS) documented by transcranial Doppler sonography and clinical signs, postoperative concentrations of ETs in the CSF remained at or were increased above levels measured before surgery. In SAH patients without CVS, the concentrations of ETs in the CSF decreased with time, whereas the time course of CVS coincided with the increase in concentrations of big ET-1 and ET-1. The temporal dependence of concentrations of big ET-1 and ET-1 in SAH patients with and without CVS were significantly different. The volume of hematoma in the basal cisterns as detected by computerized tomography was predictive of the concentrations of ETs in the CSF. Plasma concentrations of ETs were not correlated wtih CVS. The possible role of ETs in the pathogenesis of CVS associated with SAH and the controversial data reported to date are discussed.

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Hischam Bassiouni, Siamak Asgari, I. Erol Sandalcioglu, Volker Seifert, Dietmar Stolke and Gerhard Marquardt

Object

In this study, the authors' goal was to analyze a series of patients treated microsurgically for an anterior clinoid process (ACP) meningioma in regard to long-term functional outcome.

Methods

The authors retrospectively analyzed clinical data in a consecutive series of 106 patients who underwent microsurgical treatment for an ACP meningioma at 2 neurosurgical institutions between 1987 and 2005. The main presenting symptoms of the 84 female and 22 male patients (mean age 56 years) were visual impairment in 54% and headache in 28%. Physical examination revealed decreased visual acuity in 49% and a visual field deficit in 26%. Tumors were primarily resected via a pterional approach. Meningioma extensions invading the cavernous sinus, present in 29% of the patients, were not removed. Complete tumor resection (Simpson Grade I and II) was achieved in 59% of the cases.

Results

Postoperatively, visual acuity improved in 40%, was unchanged in 46%, and deteriorated in 14%. A new oculomotor palsy was observed in 8 patients (8%). Clinical and MR imaging data were available in 95 patients for a mean postsurgical period of 6.9 years (1.5–18 years) and revealed tumor recurrence in 10% and tumor progression after subtotal resection in 38%. Clinical deterioration on long-term follow-up consisting primarily of ophthalmological deficits was observed in 14% of the cases.

Conclusions

Acceptable functional results can be achieved after microsurgical resection of ACP meningiomas; however, long-term treatment remains challenging due to a high tumor recurrence and progression rate.

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