bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurocytoma in the cerebellum
Authors: Enam S. Ather , Rosenblum Mark L. , Ho Khang-Loon
Published: June 2009

✓ A neurocytoma is a central nervous system tumor composed of small cells with features of neuronal differentiation; it typically occurs in the periventricular region, close to the septum pellucidum and the foramen of Monro. In this article, the authors report the case of a neurocytoma located in the cerebellum, which to their knowledge is the first reported case of its kind. The finding of a neurocytoma at a nonclassic location refutes the theory that this tumor has its origins in subependymal progenitor cells, unless an ectopic location of progenitor cells is invoked to explain the occurrence of a neurocytoma away from the ventricles. On the basis of this case, the authors suggest that neurocytomas should be added to the differential diagnosis of mass lesions in the supratentorial intraventricular regions as well as in the posterior fossa.
Cerebral abscess as an unusual complication of coil embolization in a dural arteriovenous fistula
Authors: Zurin Adnan A. Rahman , Ushikoshi Satoshi , Houkin Kiyohiro , Kikuchi Yoichi , Abe Hiroshi , Saitoh Hisatoshi
Published: June 2009

This 63-year-old man presented with a right temporoparietal cortical infarction. A dural arteriovenous fistula involving the right transverse sinus was diagnosed on cerebral angiography. Transvenous embolization using detachable coils was performed; however, postembolization angiograms demonstrated retrograde filling of a cortical draining vein that was not seen on initial angiography. The patient subsequently developed a cerebral abscess in the region of the previous cortical infarction 2 months after the embolization. The abscess was successfully treated with drainage and antibiotic therapy. The authors report this case to illustrate an unusual complication associated with this procedure and the possible contribution of the cortical draining vein in the pathogenesis of the cerebral abscess.
Function and organization in dysgenic cortex
Authors: Preul Mark C. , Leblanc Richard , Cendes Fernando , Dubeau Francois , Reutens David , Spreafico Roberto , Battaglia Giorgio , Avoli Massimo , Langevin Pierre , Arnold Douglas L. , Villemure Jean-Guy
Published: June 2009

✓ Cerebral dysgenesis is a subject of interest because of its relationship to cerebral development and dysfunction and to epilepsy. The authors present a detailed study of a 16-year-old boy who underwent surgery for a severe seizure disorder. This patient had dysgenesis of the right hemisphere, which was composed of a giant central frontoparietal nodular gray matter heterotopia with overlying large islands of cortical dysplasia around a displaced central fissure. Exceptional insight into the function, biochemistry, electrophysiology, and histological structure of this lesion was obtained from neurological studies that revealed complementary information: magnetic resonance (MR) imaging, [18]fluoro-2-deoxy-d-glucose positron emission tomography (PET), functional PET scanning, proton MR spectroscopic (1H-MRS) imaging, intraoperative cortical mapping and electrocorticography, in vitro electrophysiology, and immunocytochemistry. These studies demonstrated compensatory cortical reorganization and showed that large areas of heterotopia and cortical dysplasia in the central area may retain normal motor and sensory function despite strikingly altered cytoarchitectonic organization and neuronal metabolism. Such lesions necessitate appropriate functional imaging studies prior to surgery and cortical mapping to avoid creating neurological deficits. Integrated studies, such as PET, 1H-MRS imaging, cortical mapping, immunocytochemistry, and electrophysiology may provide information on the function of developmental disorders of cerebral organization.
Diagnostic biopsy of the motor nerve to the gracilis muscle
Authors: Abouzahr M. Kamel , Lange Dale J. , Latov Norman , Olarte Marcelo , Rowland Lewis P. , Hays Arthur P. , Corbo Massimo
Published: June 2009

✓ A biopsy specimen of the motor nerve to the gracilis muscle was obtained in 151 patients to aid in the diagnosis of neuromuscular disorders. The procedure is simple, safe, and has low morbidity and complication rates. The surgical technique is described. Indications for the use of this technique are motor neuropathy, motor neuron disease, Guillain—Barré syndrome, and mixed neuropathy with prominent motor symptoms.
Giant fusiform intracranial aneurysms: review of 120 patients treated surgically from 1965 to 1992
Authors: Drake Charles G. , Peerless Sydney J.
Published: June 2009

✓ The paucity of information about giant fusiform intracranial aneurysms prompted this review of 120 surgically treated patients. Twenty-five aneurysms were located in the anterior and 95 in the posterior circulation. Six patients suffered from atherosclerosis and only three others had a known arteriopathy. The remaining 111 patients presented with aneurysms resulting from an unknown arterial disorder; these patients were much younger than those harboring atherosclerotic aneurysms. Mass effect occurred in only 50% of cases and hemorrhage in 20%. Eight aneurysms caused transient ischemic attacks. Hunterian proximal occlusion or trapping were dominant among the treatment methods. In contrast to the management of giant saccular aneurysms, the usual thrombotic occlusion of a giant fusiform aneurysm after proximal parent artery occlusion requires the presence of two collateral circulations to prevent infarction, one for the end vessels and another for the perforating vessels that arise from the aneurysm. Although there was some reliance on the circle of Willis and on collateral vessels manufactured at surgery, the extent of natural leptomeningeal and perforating collateral, thalamic, lenticulostriate, and brainstem vessels was astonishing and formerly unknown to the authors. Good outcome occurred in 76% of patients with aneurysms in the anterior circulation; two of the six cases with poor results included patients who were already hemiplegic. Ninety percent of patients with posterior cerebral aneurysms fared well. Only 67% of patients with basilar or vertebral aneurysms had good outcomes, although more (17%) of these patients were in poor condition preoperatively because of brainstem compression.
Intracranial aneurysms treated with the Guglielmi detachable coil: midterm clinical results in a consecutive series of 100 patients
Authors: Malisch Tim W. , Guglielmi Guido , Viñuela Fernando , Duckwiler Gary , Gobin Y. Pierre , Martin Neil A. , Frazee John G.
Published: June 2009

✓ A prospective study was designed to evaluate clinical outcome in a series of 100 consecutively treated patients who underwent endovascular embolization of 104 intracranial aneurysms using Guglielmi detachable coils (GDCs). Midterm clinical outcome (2–6 years, average 3.5 years) was obtained for 94 patients and was classified according to a modified Glasgow Outcome Scale.

Of nine patients treated in the acute phase of severe subarachnoid hemorrhage (Grade IV or V), seven died from the initial hemorrhage, one had a poor outcome, and one had a fair midterm outcome, with no post-GDC embolization hemorrhages.

Twenty patients underwent subsequent surgical or endovascular procedures that did not include the use of GDCs. These included aneurysm clipping in nine patients and parent vessel sacrifice in 11 patients. None of these 20 patients experienced post-GDC embolization hemorrhage. The postoperative midterm clinical outcomes of these 20 patients did not significantly differ from the outcomes of patients who underwent GDC embolization as their definitive treatment.

Six patients died of unrelated causes prior to reaching the 2-year survival point, with no post-GDC embolization hemorrhage. The midterm outcomes of the remaining 61 patients who underwent GDC embolization as their definitive treatment were classified as excellent (46 patients [75%]), good (seven patients [11%]), fair (three patients [5%]), poor (one patient [2%]), or dead (four patients [7%]). All four patients died from giant lesions. At midterm follow up, the surviving 57 patients' neurological statuses were unchanged or improved in 54 cases and worsened in three cases. The midterm post-GDC embolization hemorrhage rate was 0% for small aneurysms, 4% (one case) for large aneurysms, and 33% (five cases) for giant lesions.

The GDC procedure is a safe, effective, and reliable means of preventing aneurysm hemorrhage in patients with small and large intracranial aneurysms. Results, however, are less satisfactory in cases involving giant lesions. Further follow-up review is necessary to establish durability in the longer term. Patients with Grade IV or V subarachnoid hemorrhage in this series generally had poor outcomes even if the GDC procedure was successful in occluding the aneurysm.
Endovascular treatment of cerebral aneurysms following incomplete clipping
Authors: Thielen Kent R. , Nichols Douglas A. , Fulgham Jimmy R. , Piepgras David G.
Published: June 2009

✓ The authors report their experience using electrolytically detachable coils for the treatment of residual cerebral aneurysms following incomplete surgical clipping. Eight patients were treated for six anterior and two posterior circulation aneurysm remnants. All patients were referred for endovascular treatment by experienced cerebrovascular neurosurgeons at the authors' institution. Patients underwent follow-up angiography immediately after endovascular treatment. In seven of the eight patients, additional follow-up angiographic studies were obtained at periods ranging from 7 weeks to 2 years posttreatment. The latest follow-up angiograms demonstrated that six of the eight aneurysm remnants were 100% occluded, with near-complete occlusion of the other two aneurysm remnants. There was no permanent neurological or non-neurological morbidity or mortality associated with the treatment. There was no incidence of aneurysm hemorrhage during or after treatment.

Endovascular treatment of cerebral aneurysm remnants following prior surgical clipping can be accomplished with acceptable morbidity and mortality rates. Endovascular coil occlusion can play an important adjunctive role in the treatment of those aneurysms that have been incompletely obliterated by surgical clipping.
Surgical management of deep-seated dural arteriovenous malformations
Authors: Lewis Adam I. , Rosenblatt Szymon S. , Tew John M.
Published: June 2009

✓ The best treatment for deep-seated dural arteriovenous malformations (AVMs) remains controversial. Therapeutic options include transarterial and transvenous embolization, surgical excision of the dural nidus, ligation of draining veins, and stereotactically guided radiation treatment. The authors report on their experience with the application and technique of skull base surgical approaches for deep-seated dural AVMs. Their series includes six patients who were surgically treated for five tentorial dural AVMs and one inferior petrosal sinus dural AVM between 1991 and 1995. Three patients presented with progressive brainstem dysfunction, one had progressive myelopathy, and two suffered subarachnoid hemorrhage. Venous hypertension caused progressive neurological deterioration in four patients and ruptured venous aneurysms caused hemorrhage in two patients. Four of the five tentorial dural AVMs received bilateral arterial supply from the internal carotid arteries and external carotid arteries (ECAs). The dural AVM of the inferior petrosal sinus was fed from both vertebral arteries and ECAs. In this series, all dural AVMs drained into deep cerebral veins. Intra- and postoperative angiographic studies were used to document complete obliteration in each case. After surgery, three patients developed transient, delayed (24–72 hours) neurological worsening. One month postsurgery, all six patients showed improvement from their preoperative neurological function. Surgical resection of these deep-seated dural AVMs was accomplished by eliminating the arterial supply rather than ligating the draining veins to avoid aggravating the underlying venous hypertension. This study demonstrates an important role for skull base surgical approaches in the management of patients with deep-seated dural AVMs that have hemorrhaged, are not obliterated by embolization, and for which stereotactically guided radiation therapy is an unsuitable option.
High-risk mild head injury
Authors: Hsiang John N. K. , Yeung Theresa , Yu Ashley L. M. , Poon Wai S.
Published: June 2009

✓ The generally accepted definition of mild head injury includes Glasgow Coma Scale (GCS) scores of 13 to 15. However, many studies have shown that there is a heterogeneous pathophysiology among patients with GCS scores in this range. The current definition of mild head injury is misleading because patients classified in this category can have severe sequelae.

Therefore, a prospective study of 1360 head-injured patients with GCS scores ranging from 13 to 15 who were admitted to the neurosurgery service during 1994 and 1995 was undertaken to modify the current definition of mild head injury. Data regarding patients' age, sex, GCS score, radiographic findings, neurosurgical intervention, and 6-month outcome were collected and analyzed.

The results of this study showed that patients with lower GCS scores tended to have suffered more serious injury. There was a statistically significant trend across GCS scores for percentage of patients with positive acute radiographic findings, percentage receiving neurosurgical interventions, and percentage with poor outcome. The presence of postinjury vomiting did not correlate with findings of acute radiographic abnormalities.

Based on the results of this study, the authors divided all head-injured patients with GCS scores ranging from 13 to 15 into mild head injury and high-risk mild head injury groups. Mild head injury is defined as a GCS score of 15 without acute radiographic abnormalities, whereas high-risk mild head injury is defined as GCS scores of 13 or 14, or a GCS score of 15 with acute radiographic abnormalities. This more precise definition of mild head injury is simple to use and may help avoid the confusion caused by the current classification.
Combined medical and surgical treatment after acute spinal cord injury: results of a prospective pilot study to assess the merits of aggressive medical resuscitation and blood pressure management
Authors: Vale Fernando L. , Burns Jennifer , Jackson Amie B. , Hadley Mark N.
Published: June 2009

✓ The optimal management of acute spinal cord injuries remains to be defined. The authors prospectively applied resuscitation principles of volume expansion and blood pressure maintenance to 77 patients who presented with acute neurological deficits as a result of spinal cord injuries occurring from C-1 through T-12 in an effort to maintain spinal cord blood flow and prevent secondary injury. According to the Intensive Care Unit protocol, all patients were managed by using Swan—Ganz and arterial blood pressure catheters and were treated with immobilization and fracture reduction as indicated. Intravenous fluids, colloid, and vasopressors were administered as necessary to maintain mean arterial blood pressure above 85 mm Hg. Surgery was performed for decompression and stabilization, and fusion in selected cases. Sixty-four patients have been followed at least 12 months postinjury by means of detailed neurological assessments and functional ability evaluations.

Sixty percent of patients with complete cervical spinal cord injuries improved at least one Frankel or American Spinal Injury Association (ASIA) grade at the last follow-up review. Thirty percent regained the ability to walk and 20% had return of bladder function 1 year postinjury.

Thirty-three percent of the patients with complete thoracic spinal cord injuries improved at least one Frankel or ASIA grade. Approximately 10% of the patients regained the ability to walk and had return of bladder function.

As of the 12-month follow-up review, 92% of patients demonstrated clinical improvement after sustaining incomplete cervical spinal cord injuries compared to their initial neurological status. Ninety-two percent regained the ability to walk and 88% regained bladder function.

Eighty-eight percent of patients with incomplete thoracic spinal cord injuries demonstrated significant improvements in neurological function 1 year postinjury. Eighty-eight percent were able to walk and 63% had return of bladder function.

The authors conclude that the enhanced neurological outcome that was observed in patients after spinal cord injury in this study was in addition to, and/or distinct from, any potential benefit provided by surgery. Early and aggressive medical management (volume resuscitation and blood pressure augmentation) of patients with acute spinal cord injuries optimizes the potential for neurological recovery after sustaining trauma.
Duration of protective activity of cerebrospinal fluid shunt catheters impregnated with antimicrobial agents to prevent bacterial catheter-related infection
Authors: Bayston Roger , Lambert Emma
Published: June 2009

✓ This study determined the protective effect of antibacterial processing of cerebrospinal fluid (CSF) shunt catheters against infection with staphylococci, which is an important complication following CSF shunt placement for hydrocephalus. Also examined is the effect of a conditioning film such as that seen on the luminal surface of shunts used in posthemorrhagic hydrocephalus. Conventional preventative measures, including antimicrobial prophylaxis, confer a temporary or unproven benefit. The authors have therefore developed a process for impregnation of CSF shunts with rifampicin and clindamycin, and this has been shown previously to achieve the target duration of 28 days of protective activity in vitro. The present study demonstrates the limit of the period of protection and the efficacy of the processing against a wide range of staphylococci, particularly in the presence of a plasma protein conditioning film. Five strains ofStaphylococcus aureusand 17 coagulase-negative staphylococci, all clinical isolates, were inoculated into the shunts at 2-week intervals until failure of antimicrobial protection occurred. The results showed that the process protected against all strains for between 42 and 56 days and that the conditioning film did not diminish the protection. Catheters processed by this method show promise of significant reductions in the incidence of CSF shunt infections.
Absence of bleeding complications in patients undergoing cortical surgery while receiving valproate treatment
Authors: Anderson Gail D. , Lin Yi-Xin , Berge Carrie , Ojemann George A.
Published: June 2009

✓ Valproate (VPA) is associated with a variety of idiosyncratic hematological effects including thrombocytopenia, inhibition of platelet aggregation, and fibrinogen depletion. This has led some investigators to recommend discontinuation of VPA therapy prior to elective surgical procedures. However, administration of VPA therapy is not altered prior to surgery at the authors' center and no VPA-associated bleeding complications have been observed. Therefore, a retrospective chart review was conducted to verify the clinical observations in patients who had undergone cortical resection while receiving antiepileptic drugs (AEDs). Baseline, surgical, and postoperative laboratory data were available for a total of 313 patients, 111 of whom were receiving VPA and 202 of whom were receiving AEDs without VPA (control patients). Eighty-seven percent of the patients receiving VPA were also being treated with at least one other AED. The control group was approximately equally divided between monotherapy (55%) and polytherapy (45%) treatments. Platelet counts were significantly lower in the control polytherapy (284 ± 74 × 109/L) and both VPA groups (279 ± 113 × 109/L) as compared with the control monotherapy group (314 ± 85 × 109/L). Baseline fibrinogen levels were significantly lower in the VPA than in the control groups (223 ± 91 g/dl vs. 278 ± 95 g/dl). Both pre- and postoperatively, the VPA group had lower red blood cells counts, hematocrit, and hemoglobin levels. There was no significant difference between groups in estimated blood loss during surgery or qualitative wound discharge postsurgery. There was only one case of a bleeding complication, which occurred 14 days postoperatively in a patient receiving carbamazepine monotherapy. The results of this study confirm the clinical observations of an absence of bleeding complications in patients receiving VPA therapy at the time of surgery, despite differences in laboratory parameters.
Penetration of the optic chiasm by a ruptured anterior communicating artery aneurysm
Authors: Date Isao , Akioka Tatsuro , Ohmoto akashi
Published: June 2009

✓ There are few reports of anterior communicating artery aneurysms causing visual symptoms, and penetration of the optic chiasm by such aneurysms has not been reported. A 40-year-old man presented with the abrupt onset of left homonymous hemianopsia, right visual acuity disturbance (finger counting), and slight headache. Angiography disclosed a 7-mm anterior communicating artery aneurysm projecting inferiorly. After the neck of the aneurysm was clipped, the dome of the aneurysm was resected. The operation confirmed that the aneurysm had penetrated the right half of the optic chiasm and the thrombosed dome had also compressed the right optic tract. Although the aneurysm was successfully clipped, the visual disturbance persisted after surgery, suggesting that the damage to the visual pathways by aneurysm penetration was irreversible in this case.
Histopathology of arteriovenous malformations after gamma knife radiosurgery
Authors: Schneider Bernard F. , Eberhard David A. , Steiner Ladislau E.
Published: June 2009

✓ Stereotactic radiosurgery effectively obliterates many arteriovenous malformations (AVMs). Hemodynamic changes in AVMs after radiosurgery have been illustrated using magnetic resonance imaging and angiography, but there have been no detailed reports describing the underlying histopathological changes. This study examines AVMs at various times after gamma knife radiosurgery (GKRS) and describes the histopathological changes that lead to vessel occlusion.

The authors examined nine AVM specimens obtained 10 months to more than 5 years after GKRS, by using routine histopathological stains as well as immunohistochemical techniques to detect smooth-muscle actin, factor VIII, and type IV collagen.

Blood vessels within the AVMs showed progressive changes leading to narrowing or obliteration of the lumen. The earliest changes after gamma knife irradiation appear to be damage to endothelial cells, followed by progressive thickening of the intimal layer caused by proliferation of smooth-muscle cells that elaborate an extracellular matrix that includes type IV collagen. Finally, cellular degeneration and hyaline transformation occur. For statistical correlation analyses, the specimens were graded according to the degree of histopathological change and the relative number of vessels showing such changes. Both of these parameters were significantly correlated with time after GKRS and with AVM size reduction shown on follow-up imaging studies.

Gamma knife radiosurgery of AVMs causes endothelial damage, which induces the proliferation of smooth-muscle cells and the elaboration of extracellular collagen by these cells, which leads to progressive stenosis and obliteration of the AVM nidus. This series of pathological changes in AVMs after GKRS is essentially similar to the response-to-injury model of atherosclerosis.
Cigarette smoking—induced increase in the risk of symptomatic vasospasm after aneurysmal subarachnoid hemorrhage
Authors: Lasner Todd M. , Weil Robert J. , Riina Howard A. , King Joseph T. , Zager Eric L. , Raps Eric C. , Flamm Eugene S.
Published: June 2009

✓ Vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is correlated with the thickness of blood within the basal cisterns on the initial computerized tomography (CT) scan. To identify additional risk factors for symptomatic vasospasm, the authors performed a prospective analysis of 75 consecutively admitted patients who were treated for aneurysmal SAH. Five patients who died before treatment or were comatose postoperatively were excluded from the study. Of the remaining 70 patients, demographic (age, gender, and race) and clinical (hypertension, diabetes, coronary artery disease, smoking, alcohol abuse, illicit drug use, sentinel headache, Fisher grade, Hunt and Hess grade, World Federation of Neurological Surgeons grade, and ruptured aneurysm location) parameters were evaluated using multivariate logistic regression to determine factors independently associated with cerebral vasospasm. All patients were treated with hypervolemic therapy and administration of nimodipine as prophylaxis for vasospasm. Cerebral vasospasm was suspected in cases that exhibited (by elevation of transcranial Doppler velocities) neurological deterioration 3 to 14 days after SAH with no other explanation and was confirmed either by clinical improvement in response to induced hypertension or by cerebral angiography. The mean age of the patients was 50 years. Sixty-three percent of the patients were women, 74% were white, 64% were cigarette smokers, and 46% were hypertensive. Ten percent of the patients suffered from alcohol abuse, 19% from sentinel bleed, and 49% had a Fisher Grade 3 SAH. Twenty-nine percent of the patients developed symptomatic vasospasm. Multivariate analysis demonstrated that cigarette smoking (p = 0.033; odds ratio 4.7, 95% confidence interval [CI] 2.4–8.9) and Fisher Grade 3, that is, thick subarachnoid clot (p = 0.008; odds ratio 5.1, 95% CI 2–13.1), were independent predictors of symptomatic vasospasm. The authors make the novel observation that cigarette smoking increases the risk of symptomatic vasospasm after aneurysmal SAH, independent of Fisher grade.
Ganglion cyst involvement of peripheral nerves
Authors: Harbaugh Kimberly S. , Tiel Robert L. , Kline David G.
Published: June 2009

✓ Despite their benign histological appearance and the current literature composed primarily of case reports with favorable outcomes, ganglion cysts involving peripheral nerves (GCPNs) can cause permanent neurological deficits. The authors present a 27-year Louisiana State University Medical Center (LSUMC) experience with the surgical management of GCPNs. From 1968 to 1995, 27 patients were surgically treated for 27 cysts that involved nerves at nine locations. Cysts of the peroneal nerve were the most common, comprising 52% of the cases. Motor deficit, pain, and sensory changes were present in 83%, 78%, and 48% of cases, respectively. A history of acute trauma was noted in 22%. The mean follow-up duration in these cases was 61 months. Motor recovery was good in only 58% of cases and was related to the severity of the preoperative motor deficit. Pain resolved or was significantly improved in 89% of cases. Five patients underwent nine procedures before referral to LSUMC for treatment of recurrence of their ganglion cysts. None of these patients suffered recurrence after undergoing surgery at LSUMC. However, four additional patients (17%) experienced a total of six recurrences after undergoing their initial procedure. The mean time to recurrence for the patient group as a whole was 16 months. On the basis of their experience, the authors conclude that GCPNs can behave in an aggressive fashion. Patients should be counseled preoperatively about the potential for limited motor recovery and a significant chance for recurrence.
Intrathecally administered baclofen for treatment of children with spasticity of cerebral origin
Authors: Armstrong Robert W. , Steinbok Paul , Cochrane D. Douglas , Kube Susan D. , Fife Susan E. , Farrell Kevin
Published: June 2009

✓ Management of severe spasticity in children is often a difficult problem. Orally administered medications generally offer limited benefits. This study examines the value of intrathecally administered baclofen in the treatment of 19 children with severe spasticity of cerebral origin: eight of whom sustained brain injury associated with trauma, near drowning, or cardiac arrest; 10 with cerebral palsy (spastic quadriplegia); and one child with Leigh's disease. At the time of entry into the study, patients ranged from 4 to 19 years of age, and all were completely dependent on caretakers for activities of daily living.

Children who responded positively to a trial dose of intrathecal baclofen underwent insertion of a drug delivery system for continuous infusion. This was followed by a double-blind trial of baclofen or placebo and follow-up review at 3 and 6 months, and yearly thereafter. Seven children did not undergo pump implantation because of excess sedation or poor response. The 12 remaining children have been followed for a period of 1 to 5 years. Favorable responses were present in all 12 children as determined by the Ashworth Scale, with the greatest benefit being reduction of lower limb tone. Except in the case of one child who had reduction in lower limb tone that resulted in difficulty with transfers, the caretakers all reported significant benefits from intrathecal baclofen, with improvement in muscle tone, behavior, sitting, and general ease of care being most commonly noted.

Central side effects were seen in some children who received continuous intrathecal baclofen infusion and included hypotension (two patients), bradycardia (two), apnea or respiratory depression (two), and sedation (one). During a total of 568 months of pump operation there were 10 mechanical complications, including two related to pump or side port failure and eight related to catheter kinks, extrusions, or dislodgment. Pump pocket effusion occurred in five children and a cerebrospinal fluid fistula was seen in one child. Local infection occurred in three children and meningitis in two children.

The results demonstrate the potential value of continuous intrathecal baclofen infusion for treatment of severe spasticity of cerebral origin. However, this treatment can result in significant complications and more experience is required before the long-term benefits can be determined.
Resection of a large, high-flow arteriovenous malformation during hypotension and hypothermia induced by a percutaneous cardiopulmonary support system
Authors: Iwama Toru , Hashimoto Nobuo , Todaka Tatemi , Sasako Yoshikado , Inamori Syuji , Kuro Masakazu
Published: June 2009

✓ The key to successful surgical resection of cerebral arteriovenous malformations (AVMs) is control of bleeding and cerebral swelling. Induced hypotension is one of the most valuable means of achieving this control. The authors introduced induced hypotension with mild hypothermia by using a percutaneous cardiopulmonary support system (PCPS) to resect a large, high-flow AVM. The efficacy and technical points of this method are discussed.

The PCPS, whose entire intraluminal surface was coated with heparin, was established through a transfemoral route. During resection of the AVM, a mean arterial blood pressure of 60 mm Hg and a mean body temperature of 30°C were easily maintained by regulating the flow rate of the PCPS and by blood cooling. The activated coagulation time was maintained at approximately 250 seconds with a minimum systemic administration of heparin.

The authors report the case of a 30-year-old woman who presented with intraventricular hemorrhage and was diagnosed as having a large, high-flow AVM located in the left sylvian fissure. The AVM was fed by the left middle, posterior, and anterior cerebral arteries and drained by the many cortical ascending veins and the basal vein. The patient underwent surgery after hypotension and hypothermia had been induced via the PCPS method. Induced hypotension decreased the tension of the nidus and made its dissection easier. The AVM was totally resected and no hemostatic difficulties were encountered.

On the basis of the authors' experience, they suggest that hypotension and hypothermia induced by using the PCPS is a powerful tool for the successful resection of large, high-flow AVMs.
Teflon-induced granuloma following treatment of trigeminal neuralgia by microvascular decompression
Authors: Premsagar Ishwar C. , Moss Timothy , Coakham Hugh B.
Published: June 2009

✓ The authors report two cases of Teflon-induced granuloma occurring as a result of microvascular decompression using Teflon wool for the treatment of trigeminal neuralgia (TN). Teflon, which is used to separate a compressing vessel from the root entry zone (REZ) of the trigeminal nerve at the brainstem, is presumed to be an inert material. In the two cases reported here, however, Teflon induced a foreign body reaction at the REZ, causing recurrence of TN. The patients' pain was cured by complete decompression or partial sensory rhizotomy of the trigeminal sensory root at reoperation. Teflon-induced granuloma has occurred in 1.3% of the authors' series of 155 patients with TN treated using microvascular decompression. Recommendations for avoiding this complication are offered.
Spinal echinococcal cyst: treatment using computerized tomography—guided needle aspiration and hypertonic saline irrigation
Authors: Spektor Sergey , Gomori John M. , Beni-Adani Liana , Constantini Shlomo
Published: June 2009

✓ A multilocular extradural cervical spinal hydatid cyst that causes severe spinal cord compression and quadriplegia is relatively rare and difficult to treat. In a patient with this disorder, computerized tomography—guided needle aspiration of the cyst loculations and irrigation using hypertonic saline eliminated the need for emergency surgery and provided complete resolution of the patient's quadriplegia. The subsequent course of the disease was controlled by treatment with albendazole. Magnetic resonance imaging performed 4 months after the procedure demonstrated collapsed cysts and absence of spinal cord compression.
Pathophysiology of hyponatremia after transsphenoidal pituitary surgery
Authors: Olson Beatriz R. , Gumowski Julie , Rubino Domenica , Oldfield Edward H.
Published: June 2009

✓ Hyponatremia after pituitary surgery is presumed to be due to antidiuresis; however, detailed prospective investigations of water balance that would define its pathophysiology and true incidence have not been established. In this prospective study, the authors documented water balance in patients for 10 days after surgery, monitored any sodium dysregulation, further characterized the pathophysiology of hyponatremia, and correlated the degree of intraoperative stalk and posterior pituitary damage with water balance dysfunction. Ninety-two patients who underwent transsphenoidal pituitary surgery were studied. To evaluate posterior pituitary damage, a questionnaire was completed immediately after surgery in 61 patients. To examine the osmotic regulation of vasopressin secretion in normonatremic patients, water loads were administered 7 days after surgery. Patients were categorized on the basis of postoperative plasma sodium patterns.

After pituitary surgery, 25% of the patients developed spontaneous isolated hyponatremia (Day 7 ± 0.4). Twenty percent of the patients developed diabetes insipidus and 46% remained normonatremic. Plasma arginine vasopressin (AVP) was not suppressed in hyponatremic patients during hypoosmolality or in two-thirds of the normonatremic patients after water-load testing. Only one-third of the normonatremic patients excreted the water load and suppressed AVP normally. Hyponatremic patients were more natriuretic, had lower dietary sodium intake, and had similar fluid intake and cortisol and atrial natriuretic peptide (ANP) levels compared with normonatremic patients. Normonatremia, hyponatremia, and diabetes insipidus were associated with increasing degrees of surgical manipulation of the posterior lobe and pituitary stalk during surgery.

The pathophysiology of hyponatremia after transsphenoidal surgery is complex. It is initiated by pituitary damage that produces AVP secretion and dysfunctional osmoregulation in most surgically treated patients. Additional events that act together to promote the clinical expression of hyponatremia include nonatrial natriuretic peptide—related excess natriuresis, inappropriately normal fluid intake and thirst, as well as low dietary sodium intake. Patients should be monitored closely for plasma sodium, plentiful dietary sodium replacement, mild fluid restriction, and attention to symptoms of hyponatremia during the first 2 weeks after transsphenoidal surgery.
Serial proton magnetic resonance spectroscopy imaging of glioblastoma multiforme after brachytherapy
Authors: Wald Lawrence L. , Nelson Sarah J. , Day Mark R. , Noworolski Susan E. , Henry Roland G. , Huhn Steven L. , Chang Susan , Prados Michael D. , Sneed Penny K. , Larson David A. , Wara William M. , McDermott Michael , Dillon William P. , Gutin Phillip H. , Vigneron Daniel B.
Published: June 2009

✓ The utility of three-dimensional (3-D) proton magnetic resonance spectroscopy (1H-MRS) imaging for detecting metabolic changes after brain tumor therapy was assessed in a serial study of 58 total examinations of 12 patients with glioblastoma multiforme (GBM) who received brachytherapy.

Individual proton spectra from the 3-D array of spectra encompassing the lesion showed dramatic differences in spectral patterns indicative of radiation necrosis, recurrent or residual tumor, or normal brain. The 1H-MRS imaging data demonstrated significant differences between suspected residual or recurrent tumor and contrast-enhancing radiation-induced necrosis. Regions of abnormally high choline (Cho) levels, consistent with viable tumor, were detected beyond the regions of contrast enhancement for all 12 gliomas.

Changes in the serial 1H-MRS imaging data were observed, reflecting an altered metabolism following treatment. These changes included the significant reduction in Cho levels after therapy, indicating the transformation of tumor to necrotic tissue. For patients who demonstrated subsequent clinical progression, an increase in Cho levels was observed in regions that previously appeared either normal or necrotic. Several patients showed regional variations in response to brachytherapy as evaluated by 1H-MRS imaging.

This study demonstrates the potential of noninvasive 3-D 1H-MRS imaging to discriminate between the formation of contrast-enhancing radiation necrosis and residual or recurrent tumor following brachytherapy. This modality may also allow better definition of tumor extent prior to brachytherapy by detecting the presence of abnormal metabolite levels in nonenhancing regions of solid tumor.
Meningiomas involving the cavernous sinus: histological factors affecting the degree of resection
Authors: Sen Chandranath , Hague Karin
Published: June 2009

✓ Despite advances in the surgical treatment of meningiomas located at the skull base, surgery for meningiomas involving the cavernous sinus remains controversial. The controversy centers on whether complete resection of such a meningioma is possible while preserving cranial nerve function. To evaluate this question, the authors examined six patients with benign meningiomas involving the cavernous sinus. The pathological features of these tumors were evaluated and compared with the normal histoarchitecture of the cavernous sinus. The tendency of these tumors to be infiltrative is evident and this seems to occur along connective tissue planes within the cavernous sinus. This invasiveness can be explained by the peculiar structure of this region. The trigeminal nerve and ganglion seem to be particularly prone to invasion; this does not correlate with the degree of preoperative impairment of nerve function. Internal carotid artery invasion occurs frequently and can be seen even when there is no narrowing of the artery on arteriography. The pituitary gland can also be invaded by the tumor, which penetrates the thin dural barrier.
Microsurgical anatomy of the transcondylar, supracondylar, and paracondylar extensions of the far-lateral approach
Authors: Wen Hung T. , Rhoton Albert L. , Katsuta Toshiro , Oliveira Evandro de
Published: June 2009

✓ Despite a large number of reports of the use of the far-lateral approach, some of the basic detail that is important in safely completing this exposure has not been defined or remains poorly understood. The basic far-lateral exposure provides access for the following approaches: 1) the transcondylar approach directed through the occipital condyle or the adjoining portions of the occipital and atlantal condyles; 2) the supracondylar approach directed through the area above the occipital condyle; and 3) the paracondylar exposure directed through the area lateral to the occipital condyle. The transcondylar approach provides access to the lower clivus and premedullary area. The supracondylar approach provides access to the region of, and medial to, the hypoglossal canal and jugular tubercle. The paracondylar approach, which includes drilling of the jugular process of the occipital bone in the area lateral to the occipital condyle, provides access to the posterior portion of the jugular foramen and to the mastoid on the lateral side of the jugular foramen. In this study, the anatomy important to completing the far-lateral approach and these modifications was examined in 12 cadaveric specimens. In the standard posterior and posterolateral approaches, an understanding of the individual suboccipital muscles is not essential. However, these muscles provide important landmarks for the far-lateral approach and its modifications. Other important considerations include the relationship of the occipital condyle to the foramen magnum, hypoglossal canal, jugular tubercle, the jugular process of the occipital bone, the mastoid, and the facial canal. These and other relationships important to completing these exposures were examined in this study.
Implantation of C6 astrocytoma spheroid into collagen type I gels: invasive, proliferative, and enzymatic characterizations
Authors: Tamaki Masashi , McDonald Warren , Amberger Verena R. , Moore Emi , Del Maestro Rolando F.
Published: June 2009

✓ A three-dimensional model has been developed in which C6 astrocytoma spheroids of defined sizes are embedded into collagen type I gels. The authors have monitored cell invasive behavior; obtained quantitative data on cell invasion, proliferation, and enzymatic activity; assessed cell—cell interactions by altering the spheroid size used; and studied cell—matrix interactions by modifying the matrix components. Their results show that C6 astrocytoma cells detach from the spheroid surface and invade the gel as single cells by means of a system that appears to be dependent on metalloprotease function. These invasive cells have a low proliferative index. Larger spheroids with central hypoxic microregions possess cells that invade the gel at faster rates; this could be correlated with the release of increased collagen type I degrading activity. Extracellular matrix proteins, such as laminin, fibronectin, and collagen type IV have no significant influence on invasive activity, whereas hyaluronic acid decreases and human central nervous system myelin increases invasion.

New strategies directed at the treatment of malignant gliomas must take into account the subpopulation of malignant cells located long distances from the major tumor mass. The spheroid invasion model may provide specific insights into the behavior of these invasive cells.
Motor nerve transplantation
Authors: Gray William P. , Keohane Catherine , Kirwan William O.
Published: June 2009

✓ The motor nerve transplantation (MNT) technique is used to transfer an intact nerve into a denervated muscle by harvesting a neurovascular pedicle of muscle containing motor endplates from the motor endplate zone of a donor muscle and implanting it into a denervated muscle. Thirty-six adult New Zealand White rabbits underwent reinnervation of the left long peroneal (LP) muscle (fast twitch) with a motor nerve graft from the soleus muscle (slow twitch). The right LP muscle served as a control. Reinnervation was assessed using microstimulatory single-fiber electromyography (SFEMG), alterations in muscle fiber typing and grouping, and isometric response curves. Neurofilament antibody was used for axon staining. The neurofilament studies provided direct evidence of nerve growth from the motor nerve graft into the adjacent denervated muscle. Median motor endplate jitter was 13 µsec preoperatively, and 26 µsec at 2 months, 29.5 µsec at 4 months, and 14 µsec at 6 months postoperatively (p < 0.001). Isometric tetanic tension studies showed a progressive functional recovery in the reinnervated muscle over 6 months. There was no histological evidence of aberrant reinnervation from any source outside the nerve pedicle. Isometric twitch responses and adenosine triphosphatase studies confirmed the conversion of the reinnervated LP muscle to a slow-type muscle. Acetylcholinesterase studies confirmed the presence of functioning motor endplates beneath the insertion of the motor nerve graft. It is concluded that the MNT technique achieves motor reinnervation by growth of new nerve fibers across the pedicle graft into the recipient muscle.
De novo formation of a central nervous system cavernous malformation: implications for predicting risk of hemorrhage
Authors: Detwiler Paul W. , Porter Randall W. , Zabramski Joseph M. , Spetzler Robert F.
Published: June 2009

✓ The authors present a documented sporadic de novo cavernous malformation of the central nervous system (CNS) in a patient undergoing follow-up magnetic resonance imaging after resection of an acoustic neuroma. The authors believe that this is the first report of a de novo cavernous malformation in a patient without a familial history of this disease or a history of treatment with cranial radiation. The occurrence of de novo lesions invalidates the common assumption that cavernous malformations are congenital lesions. The use of this assumption to calculate bleeding risks retrospectively in patients with cavernous malformations is likely to underestimate the risk of symptomatic hemorrhage significantly. Consequently, the de novo formation of cavernous malformations may be more common than appreciated and may explain the higher bleeding rates reported in prospective compared with retrospective studies of these lesions.
Spinal epidural arteriovenous fistula with intramedullary reflux
Authors: Pirouzmand Farhad , Wallace M. Christopher , Willinsky Robert
Published: June 2009

✓ A spinal epidural arteriovenous fistula with secondary reflux into the perimedullary veins is a rare entity. The authors present such a case with a discussion of its pathophysiology and treatment. The mechanism for formation of a spinal dural arteriovenous fistula is outlined based on the anatomical substrates in this region.