Endovascular treatment of middle cerebral artery aneurysms with electrolytically detachable coils.

BACKGROUND AND PURPOSE: Middle cerebral artery (MCA) aneurysms often have an unfavorable aneurysm geometry that might limit endovascular therapy. Our purpose was to analyze the feasibility, safety, and efficacy of coil embolization in a consecutive series of MCA aneurysms chosen for endovascular treatment. PATIENTS AND TECHNIQUES: Of 235 MCA aneurysms seen at our institution during the past 5 years, 36 patients harboring 38 MCA aneurysms were primarily selected for coil embolization: 18 patients had an acute subarachnoid hemorrhage (SAH), 16 of which were due to a ruptured MCA aneurysm. SAH was classified according to Hunt and Hess grade: I (5), II (7), III (5), IV (0), and V (1). RESULTS: Complete occlusion could be achieved in 33 of 38 aneurysms. In 5 aneurysms, coil embolization was not performed because of an unfavorable aneurysm geometry with a wide neck or incorporation of adjacent branches (3) or failed because of insecure coil placement (1) or severe vasospasm (1). Procedural complications included coil protrusion into the parent artery (1), and thromboembolic M2 occlusion (5), with recanalization in 4 of 5 cases. Of 8 aneurysms with initial subtotal occlusion, 3 progressed to total occlusion during follow-up. Three aneurysms had to be retreated, and no patient rebled. Glasgow Outcome Scale at 6 months for the patients with SAH (17/18) was good recovery (12), moderate disability (4), severe disability (0), persistent vegetative state (0), and death (1); outcomes for patients with an incidental aneurysm (17/18) were good recovery (16) and moderate disability (1). CONCLUSION: Endovascular coil embolization can be performed safely and effectively in selected MCA aneurysms. Initial subtotal aneurysm occlusion might progress to total occlusion.

Hypopituitarism following severe traumatic brain injury.

Although hypopituitarism is a known complication of traumatic head injury, it may be under-recognized due to its subtle clinical manifestations. To address this issue, we determine the prevalence of neuroendocrine abnormalities in patients rehabilitating from severe traumatic brain injury (Glasgow Coma Scale < or = 8). 76 patients (mean age 39 +/- 14 yr; range 18-65; 53 males and 23 females; BMI 25.8 +/- 4.2 kg/m2; mean +/- SD) with a severe traumatic brain injury, an average of 22 +/- 10 months before this study (median, 20 months), underwent a series of standard endocrine tests, including TSH, free T4, T4, T3, prolactin, testosterone (males), estradiol (females), cortisol, ACTH, GH, and IGF-I. All subjects also underwent GH response to GHRH + arginine. Growth hormone deficiency (GHD) was defined as a GH response < 9 microg/L to GHRH + arginine and was confirmed by ITT (< 3 microg/L). Pituitary deficiency was shown in 24% of the patients (18/76). 8% (n = 6) had GHD (GH-peak range [GHRH + arginine]: 2.8-6.3 microg/L; GH-peak range [ITT]: 1.5-2.2 microg/L; IGF-I range: 62-174 microg/L). 17% (n = 13) had hypogonadism (total testosterone < 9.5 nmol/L and low gonadotropins in 12 males; low estradiol, and low gonadotropins in 1 female). Total testosterone levels did not correlate with BMI or age. 2 males with hypogonadism also showed a mild hyperprolactinemia (33 and 41 ng/ml). 3% (n = 2) patients had partial ACTH-deficiency (cortisol-peak [ITT] 392 and 417 nmol/L) and 3% (n = 2) had TSH-deficiency. In summary, we have found hypopituitarism in one-fourth of patients with predominantly secondary hypogonadism and GHD. These findings strongly suggest that patients who suffer head trauma must routinely include neuroendocrine evaluations.

[Stenting plus coiling: dangerous or helpful?]. / Stenting plus Coiling bei akut rupturierten intrakraniellen Aneurysmen.

PURPOSE: The purpose of this study was to evaluate the procedural risk of treating acute ruptured aneurysms with a stent-coil combination. MATERIAL AND METHODS: Between August 2001 and January 2004 we treated nine acute subarachnoid hemorrhage (SAH) patients with a combination of stents and platinum coils. RESULTS: Six aneurysms were 100% eliminated; the residual three aneurysms had a 95% to 99% occlusion. A transient thrombosis in the stent in one patient could be recanalized by intravenous application of ReoPro. In another patient an occlusive vasospasm at the distal end of the stent was successfully treated with intraarterial Nimotop. Neurological complications occurred in none of the patients. CONCLUSION: In broad-based aneurysms which cannot be clipped or in which any neurosurgical treatment presents an unacceptably high risk (posterior circulation and paraophthalmic aneurysms), treatment using a combination of stent and platinum coils might be an option even in the acute phase of an SAH. Platelet aggregation can be treated with Aspirin and Plavix after placement of the first coil, vasospasms with intraarterial Nimotop, and acute stent thrombosis with GP IIa/IIIb-antagonists.

Cervical intramedullary cavernous angioma with MRI-proven haemorrhages.

Two contrasting cases of cervical intramedullary cavernous angioma in young female patients are reported. One patient had a 3-year course of step-wise progressive tetraparesis; at each of the five events intramedullary bleeding from a cryptic vascular malformation at C6-7 level was diagnosed by MRI. The other patient presented with one episode which led to MRI diagnosis of a vascular malformation at the C2 level. Both patients eventually underwent complete surgical excision of the angioma with subsequent steady improvement of the neurological deficit.

Primary intracerebral sarcoma in childhood: case report with electron-microscope study.

A case of a primary intracerebral sarcoma is described in a 5-year-old girl. Histology and immunohistochemistry excluded the diagnosis of a leiomyosarcoma, a malignant haemangiopericytoma or a fibrosarcoma; electron-microscopical findings indicated that the origin of the sarcoma was in the pia mater.

Aneurysmal rupture during embolization with Guglielmi detachable coils: causes, management, and outcome.

BACKGROUND AND PURPOSE: Aneurysmal rupture during endovascular treatment is one of the most feared complications of endovascular aneurysm therapy. The purpose of this study was to determine the frequency, causes, management, and outcome of aneurysmal rupture that occurred during treatment with Guglielmi detachable coils (GDCs) in an unselected series of patients with ruptured cerebral aneurysms. METHODS: Between July 1997 and December 2000, we treated 164 acutely ruptured cerebral aneurysms with GDCs. All charts were reviewed, and patients with aneurysmal rupture occurring during embolization were identified. RESULTS: Five patients had an intraprocedural aneurysmal rupture. In one patient, rupture was due to guidewire perforation of the wall. In two patients, the microcatheter itself perforated the aneurysm. In another two patients, rupture occurred during placement of the first coil. Endovascular packing was continued in all patients. One patient died as a result of the aneurysmal rupture. No negative long-term effects were observed in the remaining four patients. In summary, we observed intraprocedural aneurysmal rupture in 3% of our patients, with a mortality rate of 20% and no long-term morbidity. CONCLUSION: Aneurysmal rupture during endovascular treatment with GDCs is a rare event; clinical severity may be variable. Embolization of the aneurysm can be continued in most cases, and most patients with treatment-related subarachnoid hemorrhage survive without serious sequelae.

Multisegmental cervical spondylosis: treatment by spondylectomy, microsurgical decompression, and osteosynthesis.

Vertebral body replacement after spondylectomy, combined with microsurgical decompression and anterior plating, was performed in 22 patients as an aggressive therapeutic approach to multisegmental cervical spondylosis. The patients were 13 men and 9 women, ranging in age from 32 to 74 years. In 19 patients, the typical signs of cervical myelopathy were present. In three patients, pain was the major symptom, accompanied by moderate spastic paresis and hyperreflexia. Apart from cervical myelography and computed tomographic scanning, which was performed in 10 patients, magnetic resonance imaging was the radiological procedure of choice in 12 patients. During spondylectomy, one vertebra was removed in 14 patients, two vertebrae in seven patients, and three vertebrae in one patient. The time of postoperative follow-up ranged from 8 to 46 months, with an average interval of 21 months. In all 22 patients, satisfactory bony fusion was achieved as demonstrated by radiological control examinations. Seventeen patients (77%) were symptom free or had only minor residual symptoms. Three (14%) patients had intermittent nuchal or cervicobrachial pain, which responded well to analgesic medication or the application of a soft collar. Two (9%) patients still had myelopathic but not incapacitating symptoms. Of 15 patients who were employed before surgery, 13 returned to a full-time job. The only severe complication of surgery was a prevertebral abscess that healed without sequelae. It is concluded that aggressive surgical therapy of multisegmental cervical spondylosis by a combination of vertebrectomy, decompression (using the surgical microscope), bone grafting, and osteosynthesis is a straightforward and promising procedure for the treatment of this debilitating disease.

Single intracisternal bolus of recombinant tissue plasminogen activator in patients with aneurysmal subarachnoid hemorrhage: preliminary assessment of efficacy and safety in an open clinical study.

Intracisternal thrombolysis with recombinant tissue plasminogen activator (rtPA) was performed in 20 patients with aneurysmal subarachnoid hemorrhage. All patients had blood accumulations in the basal cisterns according to Fisher's Grade III, thus being at a high risk for the development of posthemorrhagic delayed ischemic deficits (DID). All patients underwent an operation within 72 hours after aneurysm rupture. After the aneurysm had been excluded from the cerebral circulation, a single bolus of 10 mg of rtPA was injected into the basal cisterns. Postoperatively, serial computed tomographic examinations demonstrated radical blood clot removal in all patients. Daily transcranial Doppler examinations revealed accelerated blood flow velocities in 16 of 20 patients. The postoperative results according to the Glasgow Outcome Scale were as follows: 16 patients were Grades I and II, 2 patients were Grade III. Two patients died postoperatively, 1 because of a bowel perforation, and 1 from DID attributable to the development of a cerebral vasospasm. No postoperative bleeding complications occurred. It is concluded that pharmacological removal of subarachnoid blood accumulations can be achieved in a safe and effective way by an intrathecal single bolus of 10 mg of rtPA instilled into the basal cisterns after aneurysm clipping. The acceleration of blood flow velocities in a number of patients indicated that posthemorrhagic arterial narrowing was not completely prevented by this treatment, but this remained asymptomatic in 19 of 20 patients. Although extensive blood clot removal can be achieved by a single bolus of rtPA, more radical or complete blood removal probably requires the use of higher drug concentrations or additional postoperative intracisternal or intraventricular rtPA injections, for which further studies are needed.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser-assisted reconstruction of the oculomotor nerve: experimental study on the feasibility of cranial nerve repair.

In this experimental study the feasibility of microsurgical laser-assisted repair of the oculomotor nerve in the cat was investigated. The 3rd cranial nerve was explored after a temporobasal craniectomy from its exit at the brain stem to its entrance into the cavernous sinus and transected. The cut nerve ends were loosely reapproximated and welded together with a CO2 milliwatt laser using a power setting of 80 to 90 mW and a spot size of 150 mu. Regeneration of the oculomotor nerve within an observation period of 12 months as assessed by weekly examination of the pupil diameter was excellent in 4 animals and satisfactory in 2. In the two control groups consisting of 6 animals in which the nerve reconstruction had been performed with fibrin glue or by simple nerve reapproximation minimal nerve regeneration could be observed only in one animal. The histomorphological examinations revealed good regeneration across the laser anastomosis including new formation of a perineural sheath without any significant scarring effect or constriction at the anastomotic site. It is concluded that the CO2 milliwatt laser might be a useful tool for the microsurgical repair of cranial nerves and should possibly be incorporated into the neurosurgical armamentarium of reconstructive cranial nerve surgery.

Acute changes in the dynamics of the cerebrospinal fluid system during experimental subarachnoid hemorrhage.

Early changes in intracranial pressure (ICP), ICP volume index, and resistance to absorption of cerebrospinal fluid induced by experimental subarachnoid hemorrhage were studied in cats. After SAH, the ICP was slightly elevated, and there was a decrease in the buffering capacity of the intracranial space and a sharp rise in outflow resistance. During infusion of blood into the cisterna magna with a constant infusion rate, an extensive increase in ICP could be demonstrated in contrast to the infusion of saline, which caused only slight elevation of ICP. Furthermore, during blood infusion, the ICP level did not reach a plateau phase of pressure, as was demonstrated during infusion of saline. It is suggested that the marked increase in ICP during blood infusion into the subarachnoid space is caused by intracranial volume loading and the simultaneous increase in cerebrospinal fluid outflow resistance. It is concluded that the reported relationship between increased cerebrospinal fluid outflow resistance and increased ICP supports the hypothesis of a strong increase in ICP during subarachnoid hemorrhage in human subjects.

Influence of blood volume on cerebrospinal fluid levels of arachidonic acid metabolites after subarachnoid hemorrhage: experimental study on the pathogenesis of cerebral vasospasm.

Based on accumulating data indicating the important role of arachidonic acid metabolites in the pathogenesis of cerebral vasospasm, we examined the influence of alterations in blood volume on the cerebrospinal fluid (CSF) level of the subarachnoid hemorrhage (SAH). Three separate injections of autologous blood into the cisterna magna of dogs within subarachnoid hemorrhage (SAH). Three separate injections of autologous blood into the cisterna magna of dogs within 72 hours were performed. Three experimental groups were formed, with an overall injected blood volume of 6, 9, and 12 ml. Arterial spasm was verified by comparison of the angiographic diameter of the basilar artery on Day 8 vs. Day 1. Additionally, light microscopic, scanning and transmission electron microscopic, and freeze cracking technique examinations of the basilar artery demonstrated the typical morphological features of proliferative vasculopathy. Increasing the volume of experimental SAH led to a linear decrease of the mean vessel diameter from 45% to 53% and finally to 75% of normal. Parallel to the reduction of angiographic vessel lumen, a volume-dependent significant increase of all three eicosanoids was demonstrated. A deficiency of prostacyclin concentration during the course of the experiment was not observed. Despite highly elevated CSF levels of vasodilating prostacyclin, however, severe angiographic constriction of the basilar artery occurred in the presence of high concentrations of TXA2 and PGE2. It is concluded that increasing volumes of SAH led to a concomitant release of arachidonic acid metabolites during posthemorrhagic clot lysis. From our data, it seems questionable whether a prostacyclin deficiency is an important underlying factor for the development of cerebral spasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of single intracisternal bolus injection of recombinant tissue plasminogen activator to prevent delayed cerebral vasospasm after experimental subarachnoid hemorrhage.

Premature lysis of subarachnoid blood clots by thrombolytic substances such as urokinase and plasmin has been shown to be efficacious in preventing cerebral vasospasm in clinical and experimental investigations. Recently, tissue plasminogen activator (rtPA) derived from recombinant deoxyribonucleic (DNA) technology has been introduced as a new thrombolytic substance. With its high affinity for fibrin-bound plasminogen and low affinity for circulating plasminogen by which a clot-selective fibrinolysis can be achieved without the danger of inducing systemic fibrinogenolysis, rtPA might be the ideal substance for the postoperative lysis of cisternal blood accumulations after subarachnoid hemorrhage. The efficacy of rtPA in preventing delayed cerebral vasospasm after experimental subarachnoid hemorrhage using a single intracisternal bolus injection of this agent was investigated. With a single injection of 25 micrograms of rtPA into the cisterna magna 48 hours after the first and 6 hours after the second injection of blood in the two-hemorrhage model of cerebral vasospasm, angiographic spasm of the basilar artery was completely prevented in all animals so treated whereas in the control group severe vasospasm occurred. Autopsy studies of the experimental animals demonstrated that the subarachnoid blood clots were almost completely removed by intracisternal rtPA application. Additionally the pathomorphological signs of proliferative vasculopathy present in all animals of the control group were not demonstrable in the rtPA group. As intracisternal bolus injection of rtPA is highly efficacious in preventing angiographic as well as pathomorphological vasospasm, it is concluded that use of this thrombolytic substance might be a promising approach for pharmacological blood clot removal.

Prevention of cerebral vasospasm after experimental subarachnoid hemorrhage by RO 47-0203, a newly developed orally active endothelin receptor antagonist.

Since their discovery in 1988, endothelins have attracted scientific interest because of their extremely potent and long-lasting vasoconstrictive effects, similar to cerebral vasospasm in humans. In this study, the efficacy of the orally active endothelin receptor antagonist RO 47-0203 for prevention of cerebral vasospasm after experimental subarachnoid hemorrhage, using the two-hemorrhage dog model, was investigated. Twenty-eight beagle dogs were used in this laboratory experiment. Fourteen animals each were assigned to the treatment and control groups. In the treatment group, each dog received two single doses of 30 mg/kg RO 47-0203 orally per day. The diameter of the basilar artery decreased from 1.36 +/- 0.17 mm on Day 1 to 1.19 +/- 0.23 mm on Day 8 in the treatment group, whereas in the control group, the vessel diameter decreased from 1.48 +/- 0.19 mm on Day 1 to 1.02 +/- 0.22 mm on Day 8. These results corresponded to a decrease of vessel diameter of 13.1% +/- 11.2% in the treatment group and a decrease of vessel diameter of 30.7% +/- 12.4% in the control group (P < 0.001). Concentrations of endothelin-1 in cerebrospinal fluid significantly increased with time after subarachnoid hemorrhage. These results emphasize the important role of endothelin in the development of cerebral vasospasm and present first-time evidence that prevention of cerebral vasospasm can be achieved by the endothelin receptor antagonist RO 47-0203.

Intradiscal pressure recordings in the cervical spine.

OBJECTIVE: Experimental investigations analyzing the biomechanics of the cervical spine are less common than similar studies of other regions of the spine. There are no reports on cervical intradiscal pressure (PID) measurements in vitro. We therefore wanted to establish normal values for PID under physiological conditions by simultaneous muscle force simulation. Moreover, the impact of ventral cervical fusion should be elucidated, because in clinical studies, it is a well-known phenomenon that the adjacent segments often show increased degenerative changes. We present a pilot study. METHODS: Seven human cervical spine specimens were tested biomechanically in a specially developed spine tester. Only pure moments were used for flexion/extension, axial rotation, and lateral bending (maximal moment +/- 0.5 Nm). PID was measured simultaneously in C3-C4 and C5-C6. The specimens were tested as intact specimens and after discectomy and fusion in C4-C5. Both test situations were repeated with simulation of muscle forces. RESULTS: We found characteristic load-pressure curves for each of the three motion axes. In neutral position, PID correlated well with former published data from in vivo measurements. After fusion of C4-C5, there was a marked increase of PID in both adjacent segments (e.g., < or = 180% for axial rotation). With muscle force simulation, the increase was even higher (e.g., < or = 400% for axial rotation). CONCLUSION: For the first time, PID could be measured in the cervical spine in an experimental setting. The results obtained using normal specimens under physiological conditions confirmed those reported in two clinical studies. After cervical fusion, a marked increase in PID could be found in both adjacent segments. Presuming that an increase in PID had a negative effect on metabolism of the intervertebral disc, our results may help to explain why progressive degeneration occurs in these segments.

Posterior transpetrosal approach to aneurysms of the basilar trunk and vertebrobasilar junction.

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.

Effect of intrathecal fibrinolysis on cerebrospinal fluid absorption after experimental subarachnoid hemorrhage.

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.

Endothelin concentrations in patients with aneurysmal subarachnoid hemorrhage. Correlation with cerebral vasospasm, delayed ischemic neurological deficits, and volume of hematoma.

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 with CVS. The possible role of ETs in the pathogenesis of CVS associated with SAH and the controversial data reported to date are discussed.

Clinical and radiological evaluation of long-term results of stereotactic proton beam radiosurgery in patients with cerebral arteriovenous malformations.

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.

Intra- and postoperative complications in lumbar disc surgery.

In a prospective study, 412 primary and 69 reoperations for herniated lumbar disc were observed and intra- and postoperative complications compiled. Only surgeons with the experience of more than 100 surgical procedures on lumbar discs entered this study. The complication rates of the micro- and macrosurgical techniques are compared. Intraoperative complications range from 7.8% in the microdiskectomies and 13.7% in the macrodiskectomies to 27.5% in the reoperations. Postoperative complications range from 1.4% in reoperation, 3.9% in the microdiskectomies up to 4.2% in the macrodiskectomies. The risk of complications correlates with the age of the patient and the operating time.

[CT findings in chordomas of the base of the skull]. / CT-Befunde bei Chordomen der Schädelbasis.

Nine chordomas of the skull base and their CT appearances are described. Destruction of the clivus and of the parasellar portions of the middle fossa are characteristic, as is calcification which may be spotty, coarse or ill-defined. The tumour is characterised by marked enhancement following contrast but, on the unenhanced CT, contrary to statements in the literature, it is hypodense or isodense with respect to cerebral tissue. The tendency to recurrence and an altogether poor prognosis is confirmed.