Dennis G. Vollmer

Treatment of right hemispheric cerebral infarction by hemicraniectomy.

An anecdotal series of nine patients (three men and six women with an average age of 57 years) presented with progressive neurologic deterioration while on medical therapy for large right hemispheric cerebral infarction. Clinical signs of uncal herniation (anisocoria or fixed and dilated pupils, and/or left hemiplegia with right decerebrate posturing) were present in seven of these nine patients. Computerized tomography of the head confirmed mass effect from cerebral edema. It was the clinical judgment of the treating neurologists and neurosurgeons that each of these nine patients would perish unless surgical decompression of the infarcted brain was performed. Accordingly, each was treated with right hemicraniectomy and dural augmentation. Six patients demonstrated neurologic improvement on the first postoperative day. One patient, with a postoperative diagnosis of lung cancer, died 1 month after surgery. The remaining eight patients are currently living with their families with a follow-up period ranging from 5 to 25 months. Patient outcome as evaluated by the Barthel Index indicates that three individuals are functioning with minimal assistance and that the remaining six patients are functionally dependent. After rehabilitative therapy, four patients returned for elective cranioplasty. These results suggest that hemicraniectomy can be an effective lifesaving procedure for malignant cerebral edema after large hemispheric infarction.

Effect of the nonglucocorticoid 21-aminosteroid u74006f on experimental cerebral vasospasm

The present work was performed to establish whether the nonglucocorticoid, 21-aminosteroid, U74006F, could prevent the development of delayed cerebral vasospasm after experimental subarachnoid hemorrhage. The subarachnoid hemorrhage was produced by percutaneous injection of 4.5 mL of nonheparinized autologous blood into the cisterna magna of rabbits. U74006F (1 mg/kg) or placebo was injected intraperitoneally every 12 hours starting 12 hours prior to induction of hemorrhage for a total of six doses. The animals were sacrificed by perfusion fixation. The basilar artery was removed on day 2 and processed for morphometric analysis. Control/placebo and subarachnoid hemorrhage/placebo basilar artery diameters were 651.2 +/- 25.4 and 366.3 +/- 34.2 mu, respectively. Control/U74006F basilar artery diameters (669.8 +/- 21.8 mu) were not significantly different from that of the control/placebo group. U74006F treatment greatly minimized subarachnoid hemorrhage-induced reduction in mean luminal diameter (563.7 +/- 48.2 mu) (p less than 0.001). These results demonstrate considerable therapeutic promise for U74006F in the prevention of cerebral vasospasm.

The talon removable head frame system for stereotactic radiosurgery/radiotherapy: measurement of the repositioning accuracy

PURPOSE To present the TALON removable head frame system as an immobilization device for single-fraction intensity-modulated stereotactic radiosurgery (IMRS) and fractionated stereotactic intensity-modulated radiotherapy (FS-IMRT); and to evaluate the repositioning accuracy by measurement of anatomic landmark coordinates in repeated computed tomography (CT) examinations. METHODS AND MATERIALS Nine patients treated by fractionated stereotactic intensity-modulated radiotherapy underwent repeated CTs during their treatment courses. We evaluated anatomic landmark coordinates in a total of 26 repeat CT data sets and respective x, y, and z shifts relative to their positions in the nine treatment-planning reference CTs. An iterative optimization algorithm was employed using a root mean square scoring function to determine the best-fit orientation of subsequent sets of anatomic landmark measurements relative to the original image set. This allowed for the calculation of the x, y, and z components of translation of the target isocenter for each repeat CT. In addition to absolute target isocenter translation, the magnitude (sum vector) of isocenter motion and the patient/target rotation about the three principal axes were calculated. RESULTS Anatomic landmark analysis over a treatment course of 6 weeks revealed a mean target isocenter translation of 0.95 +/- 0.55, 0.58 +/- 0.46, and 0.51 +/- 0.38 mm in x, y, and z directions, respectively. The mean magnitude of isocenter translation was 1.38 +/- 0.48 mm. The 95% confidence interval ([CI], mean translation plus two standard deviations) for repeated isocenter setup accuracy over the 6-week period was 2.34 mm. Average rotations about the x, y, and z axes were 0.41 +/- 0.36, 0.29 +/- 0.25, and 0.18 +/- 0.15 degrees, respectively. Analysis of the accuracy of the first repeated setup control, representative of single-fraction stereotactic radiosurgery situations, resulted in a mean target isocenter translation in the x, y, and z directions of 0.52 +/- 0.38, 0.56 +/- 0.30, and 0.46 +/- 0.25 mm, respectively. The mean magnitude of isocenter translation was 0.99 +/- 0.28 mm. The 95% confidence interval for these radiosurgery situations was 1.55 mm. Average rotations at first repeated setup control about the x, y, and z axes were 0.24 +/- 0.19, 0.19 +/- 0.17, and 0.19 +/- 0.12 degrees, respectively. CONCLUSION The TALON relocatable head frame was seen to be well suited for immobilization and repositioning of single-fraction stereotactic radiosurgery treatments. Because of its unique removable design, the system was also seen to provide excellent repeat immobilization and alignment for fractionated stereotactic applications. The exceptional accuracy for the single-fraction stereotactic radiosurgical application of the system was seen to deteriorate only slightly over a 6-week fractionated stereotactic treatment course.

Retrospective analysis of unstaged and staged Gamma Knife surgery with and without preceding embolization for the treatment of arteriovenous malformations

OBJECT The authors conducted a retrospective study to examine data on rates of obliteration of arteriovenous malformations (AVMs) with use of various combinations of treatment modalities based on Gamma Knife surgery (GKS). The authors believe that this study is the first to report on patients treated with embolization followed by staged GKS. METHODS The authors identified 150 patients who underwent GKS for treatment of AVMs between 1994 and 2004. In a retrospective study, 4 independent groups emerged based on the various combinations of treatment: 92 patients who underwent unstaged GKS, 28 patients who underwent embolization followed by unstaged GKS, 23 patients who underwent staged GKS, and 7 patients who underwent embolization followed by staged GKS. A minimum of 3 years of follow-up after the last GKS treatment was required for inclusion in the retrospective analysis. Angiograms, MR images, or CT scans at follow-up were required for calculating rates of obliteration of AVMs. RESULTS Fifty-seven of 150 patients (38%) supplied angiograms, and overall obliteration was confirmed in 43 of these 57 patients (75.4%). An additional 37 patients had follow-up MR images or CT scans. The overall obliteration rate, including patients with follow-up angiograms and patients with follow-up MR images or CT scans, was 68 of 94 (72.3%). Patients who underwent unstaged GKS had a follow-up rate of 58.7% (54 of 92) and an obliteration rate of 75.9% (41 of 54). Patients who underwent embolization followed by unstaged GKS had a follow-up rate of 53.5% (15 of 28) and an obliteration rate of 60.0% (9 of 15). Patients who underwent staged GKS had a follow-up rate of 82.6% (19 of 23) and an obliteration rate of 73.7% (14 of 19). Patients who underwent embolization followed by staged GKS had a follow-up rate of 85.7% (6 of 7) and an obliteration rate of 66.7% (4 of 6). CONCLUSIONS Gamma Knife surgery is an effective means of treating AVMs. Embolization prior to GKS may reduce AVM obliteration rates. Staged GKS is a promising method for obtaining high obliteration rates when treating larger AVMs in eloquent locations.

An unusual case of the complete Currarino triad: case report, discussion of the literature and the embryogenic implications.

OBJECTIVE AND IMPORTANCE We present and illustrate an unusual case of the complete familial Currarino triad (an association between a bony sacral defect, a presacral mass, and an anorectal malformation) in which the teratoma arose from the conus medullaris and contained mature neurons, glia, and branching ependymal canals that were in communication with a terminal syrinx. The embryogenic implications are discussed. CLINICAL PRESENTATION The patient was a term neonate when discovered to have imperforate anus. Further workup revealed lumbosacral dysraphism with a presacral mass, a rectovaginal fistula, and a single pelvic kidney. The family pedigree revealed a familial transmission pattern; the patient had a second cousin with anal atresia and a first cousin with similar sacral anomalies. The motor level was L4 with trace L5, and there was absent sensation in the sacral dermatomes. INTERVENTION A diverting colostomy was performed on Day 14, and the infant returned at 3 months of age to undergo near-total resection through the previous abdominal approach. Only a subtotal resection was possible because the mass arose from the low-lying conus and was firmly adherent to the sacral nerve roots and iliac vessel. Follow-up magnetic resonance imaging performed 18 months after surgery revealed that the residual tumor had not progressed. CONCLUSION Complete Currarino triad is rare and is familial in half of the cases. The special features of the tumor in our case were the presence of mature neurons with ependymal canals and its origin from the conus. The possible embryogenesis may provide evidence that the caudal notochord is important for organized secondary neurulation.

Cerebral mycotic aneurysms treated with a neuroform stent: technical case report.

OBJECTIVE AND IMPORTANCE: We describe the first documented endovascular treatment of proximal intracranial mycotic aneurysms by a self-expanding, flexible, dedicated, intracranial Neuroform stent. Treatment with this stent rapidly obliterated the aneurysms, eliminated the need for additional coiling, and maintained the patency of the parent arteries. CLINICAL PRESENTATION: A 47-year-old male patient with infective endocarditis presented with ischemic stroke and minimal subarachnoid hemorrhage. Cerebral angiography demonstrated a fusiform aneurysm of the supraclinoid segment of the left internal carotid artery and horizontal segment of the left middle cerebral artery, with superimposing side-wall focal aneurysms. Despite antibiotic therapy, the focal aneurysms progressively enlarged, as demonstrated on a subsequent cerebral angiogram at Day 11. INTERVENTION: A 4-mm × 2-cm Neuroform stent was deployed along the fusiform aneurysm of the left supraclinoid internal carotid artery and the horizontal middle cerebral artery M-1 segment encompassing the focal side-wall aneurysms with preserved patency of the parent arterial segments. CONCLUSION: Endovascular stent placement can be an effective treatment for proximal intracranial mycotic aneurysms that fail to respond to medical therapy.Accepted, September 7, 2005. OBJECTIVE AND IMPORTANCE: We describe the first documented endovascular treatment of proximal intracranial mycotic aneurysms by a self-expanding, flexible, dedicated, intracranial Neuroform stent. Treatment with this stent rapidly obliterated the aneurysms, eliminated the need for additional coiling, and maintained the patency of the parent arteries. CLINICAL PRESENTATION: A 47-year-old male patient with infective endocarditis presented with ischemic stroke and minimal subarachnoid hemorrhage. Cerebral angiography demonstrated a fusiform aneurysm of the supraclinoid segment of the left internal carotid artery and horizontal segment of the left middle cerebral artery, with superimposing side-wall focal aneurysms. Despite antibiotic therapy, the focal aneurysms progressively enlarged, as demonstrated on a subsequent cerebral angiogram at Day 11. INTERVENTION: A 4-mm 2-cm Neuroform stent was deployed along the fusiform aneurysm of the left supraclinoid internal carotid artery and the horizontal middle cerebral artery M-1 segment encompassing the focal side-wall aneurysms with preserved patency of the parent arterial segments. CONCLUSION: Endovascular stent placement can be an effective treatment for proximal intracranial mycotic aneurysms that fail to respond to medical therapy.

Cervical meningocele and associated spinal anomalies

Simple meningoceles are infrequent forms of dysraphism and are often benign. They have been associated with other spinal anomalies. The uncommon cervical meningocele may have a higher propensity to be associated with other spinal anomalies. Four patients with cervical meningocele are presented with radiographic evaluation and clinical course. Multiple abnormalities were documented radiographically and operatively, including hydrocephalus, Chiari malformation, hydromyelia, lipomeningomyelocele, tethered cord, thickened filum terminale, diastematomyelia, Klippel-Feil syndrome, and thoracic hemivertebrae. Prior to the development of any late neurological abnormality from associated spinal anomalies, magnetic resonance imaging is recommended early in a child born with a simple meningocele.

The effect of nicardipine on vasospasm in rabbit basilar artery after subarachnoid hemorrhage.

This study was performed to examine the effect of the dihydropyridine calcium antagonist, nicardipine, on vasospasm after experimental subarachnoid hemorrhage (SAH) in the rabbit. The study was carried out in two parts: 1) effect of intravenous nicardipine (n = 45) and 2) effect of intracisternal nicardipine (n = 21). SAH was induced by injecting 5 ml of autologous arterial blood into the cisterna magna. In the intravenous study, there were five groups: 1) SAH without treatment; 2) SAH with vehicle (saline); 3) SAH and intravenous infusion of low-dose nicardipine (0.01 mg/kg/h); 4) SAH and intravenous infusion of high-dose nicardipine (0.15 mg/kg/h); and 5) controls without SAH. The intravenous infusions were started immediately after SAH and continued for 48 hours until death. In the intracisternal study, there were three groups: 1) SAH without treatment; 2) SAH with intracisternal administration of nicardipine (0.37 mg/h); and 3) controls without SAH. Intracisternal infusions were begun 70 hours after SAH and continued for 2 hours until death. After perfusion-fixation, the basilar artery was removed and processed for morphometric analysis. In the intravenous study, vessels from animals subjected to SAH were significantly narrowed when compared with controls, although after high-dose nicardipine vessel caliber was slightly larger than in the other SAH groups. Animals given intracisternal nicardipine showed a nonsignificant reduction of caliber as compared with controls: only 12% decrease in diameter and 22% decrease in luminal area. In the rabbit SAH model, nicardipine had a very modest effect on vasospasm at the doses tested.

Muscarinic cholinergic receptors on the endothelium of human cerebral arteries

To characterize the muscarinic cholinergic receptors on the endothelium of human cerebral arteries, isometric tension measurement and receptor autoradiographic studies were performed. Acetylcholine (ACh) induced dose-dependent relaxation of human cerebral arteries precontracted by 10−5 M serotonin, with an EC50 of 1.9 ± 0.6 × 10−6 M (n = 7). The relaxation was abolished by 10−5 M hemoglobin. Autoradiography, using the muscarinic antagonist [3H]propylbenzilylcholine mustard, demonstrated the high density of muscarinic cholinergic receptors on the endothelial cells of human cerebral arteries, especially on the luminal surface of the endothelium. These findings suggest that ACh-induced relaxation mediated by muscarinic cholinergic receptors on the endothelium has a physiological function in human cerebral arteries.

Time course of the blood-arterial wall barrier disruption following experimental subarachnoid haemorrhage

SummaryThe time course of the blood-arterial wall barrier disruption following experimental subarachnoid haemorrhage (SAH) was studied in 24 rabbits. Animals with SAH received two successive blood injections through the cisterna magna. Horseradish peroxidase (HRP) was given intravenously 30 minutes before sacrifice to assess the integrity of the barrier. In the basilar arteries taken from animals that were sacrificed 4 days after the first SAH, HRP-reaction products were diffusely observed in the subendothelial space. Three weeks following the first SAH, permeation of HRP was still observed in half of the animals. However, in animals sacrificed 7 weeks after the first SAH, no permeation of HRP into the subendothelial space was noted. Opening of the interendothelial space seemed to be the major mechanism for HRP permeation into the subendothelial space rather than transendothelial vesicular transport. Disruption of the bloodarterial wall barrier in the major cerebral arteries following SAH may play a role in the pathogenesis of vasospasm.