bluuebunny/crossref_metadata_2025_split huggingface dataset:
The widened retrolabyrinthine approach: a new concept in acoustic neuroma surgery
Authors: Darrouzet Vincent , Guerin Jean , Aouad Naaman , Dutkiewicz Jaromir , Blayney Alexander W. , Bebear Jean-Pierre 
Published: June 2009

✓ For many years, the retrolabyrinthine approach has been limited to functional surgery of the cerebellopontine angle (CPA). As a result of the increased surgical exposure, particularly the opening of the internal auditory meatus (IAM), the widened retrolabyrinthine technique permits tumor excision from both the CPA and the IAM, regardless of the histological nature of the tumor. The authors have treated 60 acoustic neuromas of varying sizes via this approach (6% intrameatal tumors; 30% > 25 mm in diameter). The postoperative mortality rate was 0%. The risk of fistula formation was 3.3%, and 3.3% of the patients suffered from postoperative meningitis. The results for facial nerve function were equivalent to those obtained previously via a widened translabyrinthine approach and those in a series treated via a suboccipital approach (80% with Grades I and II, 15% with Grade III, and 5% with Grades V and VI). One patient (1.7%) required a secondary hypoglossal—facial nerve anastomosis and had attained a Grade IV result 6 months later. Postoperatively 21.7% of these patients maintained socially useful hearing and 20% had mediocre hearing. Socially useful hearing was preserved in 50% of a subgroup of 20 patients who had both good preoperative hearing and a tumor that involved less than half of the IAM regardless of its volume. Additionally, 15% had mediocre hearing that could be improved with hearing aids.Because of its efficacy in preserving hearing, the authors favor the retrolabyrinthine over the occipital approach, with the latter being considered less subtle and more aggressive.
Hydroxyurea for treatment of unresectable and recurrent meningiomas. II. Decrease in the size of meningiomas in patients treated with hydroxyurea
Authors: Schrell Uwe M. H. , Rittig Michael G. , Anders Marc , Koch Uwe H. , Marschalek Rolf , Kiesewetter Franklin , Fahlbusch Rudolf 
Published: June 2009

✓ In this paper the authors present the first evidence that meningiomas respond to treatment with hydroxyurea. Hydroxyurea was administered as an adjunct chemotherapeutic treatment in patients with recurrent and unresectable meningiomas. Hydroxyurea was used because experimental data demonstrated that it inhibits growth of cultured human meningioma cells and meningioma transplants in nude mice by inducing apoptosis. The authors therefore treated four selected patients with hydroxyurea. All patients had undergone multiple gross resections and all except one received radio-therapy. Three patients with recurrent Grade I meningiomas assessed according to World Health Organization (WHO) guidelines received hydroxyurea because of an increased tumor growth rate, documented by magnetic resonance (MR) imaging, within a 6- or 12-month interval. A fourth patient with a malignant meningioma (WHO Grade III) began a course of treatment with hydroxyurea immediately after his sixth palliative operation without waiting for another relapse to be demonstrated on MR imaging. Because of their location and invasive growth behavior none of the meningiomas could have been removed completely by surgical intervention.
All patients received hydroxyurea at a dosage level of 1000 to 1500 mg/day (approximately 20 mg/kg/day). In a man with a large sphenoid wing meningioma invading the right cavernous sinus and the temporal base, the intracranial tumor mass was reduced by 60% during 6 months of treatment. A woman with a large ball-shaped meningioma of the right sphenoid wing invading the cavernous sinus exhibited a 74% decrease of the initial tumor volume in 10 months of treatment with oral hydroxyurea. Serial MR images obtained monthly revealed that the process of size reduction was continuous and proportionate. The shrinkage of the tumor was accompanied by a complete remission of symptomatic trigeminal neuralgia after 2 months and by improved abducent paresis after 5 months. The third patient had a slowly growing meningioma that exhibited a 15% reduction in mass when reassessed after 5 months of hydroxyurea treatment. The fourth patient with the malignant meningioma in the left cerebellopontine angle has had no recurrence for 24 months. Long-term treatment with hydroxyurea may result in full remission of tumors in meningioma patients.
The preliminary data indicate that hydroxyurea provides true medical treatment in patients with unresectable and recurrent meningiomas, replacing palliative surgery and radiotherapy in the management of this disease.
Spatial pattern of type I collagen expression in injured peripheral nerve
Authors: Nath Rahul K. , Mackinnon Susan E. , Jensen John N. , Parks William C. 
Published: June 2009

✓ The authors studied the spatial expression and regulation of messenger RNA for the a 1 subunit of collagen type I in crushed rat sciatic nerve to provide a basis for future therapeutic manipulation.
Sciatic nerves in 20 male or female adult Lewis rats were crushed for 60 seconds; the unharmed contralateral sciatic nerves served as controls. Twenty-one days after injury the experimental animals were killed and their tissue was harvested. The spatial expression of collagen type I was determined by using in situ hybridization techniques. Quantification of fibroblast number and total signal was performed through computerized morphometry. Collagen upregulation was evident in epineurial and perineurial layers, with the epineurium displaying higher activity. The cells responsible for procollagen type I production were fibroblasts. No activity was seen in the endoneurium.
Morphometric findings indicated that collagen upregulation in the epineurium and perineurium occurred at both pretranscriptional and posttranslational levels when compared to controls; a paired t-test analysis confirmed statistical significance for all comparisons between injured and control tissues.
Epineurial fibroblasts are responsible for the collagen production associated with crushed peripheral nerve injury in the rat. Regulation occurs pretranscriptionally as well as posttranslationally. It is interesting to speculate that the delivery of agents directed against collagen production (such as neutralizing antibodies to growth factors) into epineurial tissues proximate to the time and location of clinical nerve injury might mitigate later deleterious effects of excess collagen production in axonal regeneration.
Long-term improvement in patients with severe Parkinson's disease after implantation of fetal ventral mesencephalic tissue in a cavity of the caudate nucleus: 5-year follow up in 10 patients
Authors: López-Lozano Juan J. , Bravo Gonzalo , Brera Begoña , Millán Isabel , Dargallo Jose , Salmeán Javier , Uría Jose , Insausti Jose , _ _ 
Published: June 2009

✓ Different groups worldwide have observed in recent years that stereotactic implantation of fetal tissue can ameliorate the clinical symptoms of Parkinson's disease. The authors therefore investigated whether implantation of fetal ventral mesencephalic (FVM) tissue via open surgery is also capable of producing an improvement and whether this improvement is transient or long lasting. The authors report their findings in a 5-year follow-up study in 10 patients with Hoehn and Yahr Grade IV or V Parkinson's disease in whom a single FVM graft was implanted in a cavity created in the right caudate nucleus. The results indicate that the implants improved motor function and that clinical recovery persisted in seven of the 10 patients 5 years after implantation. Amelioration was observed in both the on and off phases and was accompanied by a 64% reduction in the levodopa dose and withdrawal of the dopamine agonist. The on phase was prolonged from 39% of the waking day to 72%, with reduced intensity and duration of dyskinesias. All symptoms that were analyzed showed improvement, although they differed in intensity and time of onset. The course of improvement seemed to be stepwise, with significant improvement between 5 and 7 months postimplantation followed by two waves of progress peaking in Months 15 and 36. Withdrawal of cyclosporine in three patients after more than 2 years of administration produced a decline in the patients' clinical conditions.
In conclusion, the results indicate that open surgery implantation of FVM tissue in the caudate nucleus improves the clinical condition of parkinsonian patients and that this improvement can persist for at least 5 years. In comparison with two earlier series reported by the authors, which involved implants of perfused adrenal medulla and coimplantation of adrenal medulla and peripheral nerve, the course and pattern of improvement in these implant recipients suggests that their recovery can be attributed to more than one factor.
Characterization of cerebral hemodynamic phases following severe head trauma: hypoperfusion, hyperemia, and vasospasm
Authors: Martin Neil A. , Patwardhan Ravish V. , Alexander Michael J. , Africk Cynthia Zane , Lee Jae Hong , Shalmon Ehud , Hovda David A. , Becker Donald P. 
Published: June 2009

✓ The extent and timing of posttraumatic cerebral hemodynamic disturbances have significant implications for the monitoring and treatment of patients with head injury. This prospective study of cerebral blood flow (CBF) (measured using 133Xe clearance) and transcranial Doppler (TCD) measurements in 125 patients with severe head trauma has defined three distinct hemodynamic phases during the first 2 weeks after injury. The phases are further characterized by measurements of cerebral arteriovenous oxygen difference (AVDO2) and cerebral metabolic rate of oxygen (CMRO2). Phase I (hypoperfusion phase) occurs on the day of injury (Day 0) and is defined by a low CBF15 calculated from cerebral clearance curves integrated to 15 minutes (mean CBF15 32.3 ± 2 ml/100 g/minute), normal middle cerebral artery (MCA) velocity (mean VMCA 56.7 ± 2.9 cm/second), normal hemispheric index ([HI], mean HI 1.67 ± 0.11), and normal AVDO2 (mean AVDO2 5.4 ± 0.5 vol%). The CMRO2 is approximately 50% of normal (mean CMRO2 1.77 ± 0.18 ml/100 g/minute) during this phase and remains depressed during the second and third phases. In Phase II (hyperemia phase, Days 1–3), CBF increases (46.8 ± 3 ml/100 g/minute), AVDO2 falls (3.8 ± 0.1 vol%), VMCA rises (86 ± 3.7 cm/second), and the HI remains less than 3 (2.41 ± 0.1). In Phase III (vasospasm phase, Days 4–15), there is a fall in CBF (35.7 ± 3.8 ml/100 g/minute), a further increase in VMCA (96.7 ± 6.3 cm/second), and a pronounced rise in the HI (2.87 ± 0.22).
This is the first study in which CBF, metabolic, and TCD measurements are combined to define the characteristics and time courses of, and to suggest etiological factors for, the distinct cerebral hemodynamic phases that occur after severe craniocerebral trauma. This research is consistent with and builds on the findings of previous investigations and may provide a useful temporal framework for the organization of existing knowledge regarding posttraumatic cerebrovascular and metabolic pathophysiology.
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.
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.
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.