bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endovascular embolization of 150 basilar tip aneurysms with Guglielmi detachable coils: results of the Food and Drug Administration multicenter clinical trial
Authors: Eskridge Joseph M. , Song Joon K. , _ _ 
Published: June 2009

Object.To assess the safety and efficacy of aneurysm embolization performed using Guglielmi detachable coils (GDCs), the authors reviewed the results of a cohort of 150 patients with either ruptured (83 patients) or unruptured (67 patients) basilar tip aneurysms treated with these detachable platinum coil devices in the early part of the United States multicenter GDC clinical trial that led to Food and Drug Administration approval for the device.Methods.The most common presentation in this cohort of patients was headache (53%). All patients were entered into the trial after neurosurgical assessment excluded them as candidates for surgical clipping of their aneurysms. Greater than 90% coil packing was achieved in 75% of the patients. For those patients in whom follow-up information was available, the mean angiographic and clinical evaluation follow-up time for 61 patients with ruptured aneurysms was 13.7 months (range 0–43 months) and that for the 49 patients with unruptured aneurysms was 9.8 (range 0–40 months). Conservative mortality rates included up to 23% for the ruptured aneurysm group and up to 12% for the unruptured aneurysm group; the rebleeding rate for treated ruptured aneurysms was up to 3.3% and the bleeding rate for unruptured aneurysms up to 4.1%. Permanent deficits due to stroke in patients with ruptured or unruptured aneurysms occurred in up to 5% and 9%, respectively. Vasospasm occurred in 8% of the patients; it was associated with two deaths. Periprocedural mortality was 2.7% (four patients with ruptured aneurysms).Conclusions.Detachable platinum coil embolization is a promising treatment for ruptured basilar tip aneurysms that are not surgically clippable; in selected patients it offers lower incidences of morbidity and mortality compared with conservative medical management. The role of this procedure in unruptured basilar tip aneurysms is unclear with less supportive results. More long-term follow-up evaluation is necessary and results are expected to improve.
Seasonal pattern of spontaneous cervical artery dissection
Authors: Schievink Wouter I. , Wijdicks Eelco F. M. , Kuiper James D. 
Published: June 2009

Object. The etiology of spontaneous cervical artery dissection is poorly understood; however, it may involve genetic and environmental factors. The purpose of this study was to determine whether seasonality of spontaneous cervical artery dissection exists.
Methods. The seasonal pattern of spontaneous cervical artery dissection was analyzed in a group of 200 consecutive patients (104 females and 96 males with a mean age of 44.9 years) who were evaluated using the Rayleigh test during the period from 1970 to 1990. The majority of patients resided in the midwestern section of the United States, where large seasonal fluctuations in climate occur. A circannual periodicity was found in the frequency of spontaneous cervical artery dissections with a peak occurring in October (p < 0.02). The seasonal variation was substantial, with approximately 58% more patients suffering a cervical artery dissection during autumn than during other seasons.
Conclusions. A seasonal pattern of spontaneous cervical artery dissection exists with a peak occurring in October. The cause of the seasonality remains to be explained; however, weather- or infectious disease—related factors may provide etiological leads.
The effect of subarachnoid hemorrhage on mechanisms of vasodilation mediated by cyclic adenosine monophosphate
Authors: Onoue Hisashi , Katusic Zvonimir S. 
Published: June 2009

Object.This study was designed to determine whether subarachnoid hemorrhage (SAH) affects the function of the K+channels responsible for relaxation of canine cerebral arteries in response to adenylate cyclase activation.Methods.The effect of K+channel inhibitors on the arterial relaxation response to forskolin, a direct adenylate cyclase activator, was studied in rings of basilar arteries obtained from normal dogs and dogs in which SAH was induced (double-hemorrhage model). The levels of adenosine 3′,5′-cyclic monophosphate (cAMP) were measured using the radioimmunoassay technique. In rings with the endothelium removed, relaxation induced by forskolin was not affected by SAH. The relaxation response to forskolin was reduced by charybdotoxin (1027 mol/L), a selective Ca++-activated K+channel inhibitor, in normal arteries and arteries subjected to autologous blood injection. This inhibitory effect of charybdotoxin was significantly greater in arteries involved in SAH than in normal vessels. The relaxation response to forskolin was reduced by 4-aminopyridine (10−3mol/L), a delayed rectifier K+channel inhibitor, only in arteries involved in SAH. In contrast, the relaxation response to forskolin was not affected by glyburide (10−5mol/L), an adenosine 5′—triphosphate-sensitive K+channel inhibitor, in both normal and SAH arteries. Forskolin (3 × 10−7mol/L) produced an approximately 10-fold increase in levels of cAMP. The basal values and increased levels of cAMP detected after stimulation with forskolin were no different in normal arteries and those exposed to SAH.Conclusions.These results demonstrate that formation of cAMP and the relaxation response to adenylate cyclase activation are not affected by SAH. However, in diseased arteries, K+channels assume a more important role in the mediation of relaxation response to forskolin, indicating that SAH may change the mechanisms responsible for vasodilation induced by cAMP.
Long-term follow-up results of laminectomy for cervical myelopathy caused by ossification of the posterior longitudinal ligament
Authors: Kato Yasuji , Iwasaki Motoki , Fuji Takeshi , Yonenobu Kazuo , Ochi Takahiro 
Published: June 2009

Object. This retrospective study was performed to assess the long-term results of cervical laminectomy in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.
Methods. The authors reviewed medical records in 44 of 52 patients who underwent cervical laminectomy between 1970 and 1985 (mean follow up 14.1 years). The neurological recovery rate after laminectomy was 44.2% after 1 year and 42.9% after 5 years. The surgical outcome was maintained after 5 years but worsened between 5 and 10 years postsurgery: the recovery rate at the last follow-up review was 32.8%. Using multivariate stepwise analysis, the preoperative factors that affected clinical results were found to be the age at operation, the severity of preexisting myelopathy, and a history of trauma. Late neurological deterioration was observed in 10 (23%) of 44 patients. The earliest deterioration occurred at 1 year and the latest was at 17 years postsurgery (mean 9.5 years). The most frequent cause of deterioration was trauma due to a fall (six patients), followed by ossification of the ligamentum flavum (three patients). Postoperative spread of the OPLL was noted in 70% of the patients, but it was clearly the cause of neurological deterioration in only one of them. After laminectomy, postoperative progression of kyphotic deformity was observed in 47% of patients, but these changes did not cause neurological deterioration.
Conclusions. The authors recommend early surgical decompression for OPLL because the outcome is better for younger patients and for those with a higher score as measured by the Japanese Orthopedic Association's system.
Thoracoscopic microsurgical excision of herniated thoracic discs
Authors: Rosenthal Daniel , Dickman Curtis A. 
Published: June 2009

Object. The authors began using thoracoscopy to treat pathological conditions of the spine in 1992. In this study they delineate their clinical experience in which this procedure was used to resect herniated thoracic discs.
Methods. Fifty-five patients underwent thoracoscopy for the resection of herniated thoracic discs. Thirty-six patients presented with myelopathies and 19 with incapacitating thoracic radicular pain. Forty-three patients underwent a single-level, 11 a two-level, and one a three-level discectomy. The mean operative time for thoracoscopic microdiscectomy was 3 hours and 25 minutes (range 80–542 minutes) and the mean blood loss was 327 ml (range 124–1500 ml). Compared with thoracotomy, which was performed in 18 patients, thoracoscopy was associated with a mean of 1 hour less operative time and less than one-half of the blood loss, duration of chest tube drainage, usage of pain medication, and length of hospitalization. Compared with costotransversectomy, which was performed in 15 patients, thoracoscopy permitted more complete resection of calcified and midline thoracic discs because it provided a direct view of the entire anterior surface of the dura. Thoracotomy was associated with a significantly greater incidence of prolonged, disabling intercostal neuralgia compared with the mild transient episodes of intercostal neuralgia associated with thoracoscopy (50% compared with 16%). Thoracotomy also was associated with a significantly higher incidence of postoperative atelectasis and pulmonary dysfunction than thoracoscopy (33% compared with 7%). Clinical and neurological outcomes were excellent (mean follow-up period 15 months). Among the 36 myelopathic patients, 22 completely recovered neurologically; five improved functionally but had some residual myelopathic symptoms; and nine stabilized. Among the 19 patients with isolated thoracic radiculopathies, 15 recovered completely and four improved moderately; no patient had worsened radicular pain.
Conclusions. Thoracoscopic microdiscectomy is a reliable surgical technique that can be performed safely with excellent clinical and neurological results.
Relationships among cerebral perfusion pressure, autoregulation, and transcranial Doppler waveform: a modeling study
Authors: Ursino Mauro , Giulioni Marco , Lodi Carlo Alberto 
Published: June 2009

Object. The aim of this study was to analyze how the main values extrapolated from the transcranial Doppler (TCD) waveform (systolic, mean, and diastolic velocity; velocity peak-to-peak amplitude; and pulsatility index [PI]) are affected by changes in intracranial pressure (ICP), systemic arterial pressure (SAP), autoregulation, and intracranial compliance.
Methods. The analysis was performed using a mathematical model of the intracranial dynamics. This model includes a passive middle cerebral artery, the biomechanics of large and small pial arteries subjected to autoregulatory mechanisms, a collapsing venous cerebrovascular bed, the cerebrospinal fluid circulation, and the ICP—volume relationship.
The results indicate that there are approximately three distinct zones characterized by different relationships between cerebral perfusion pressure (CPP) and velocity parameters in patients with preserved autoregulation. In the central autoregulatory zone (CPP > 70 mm Hg) the mean velocity does not change with decreasing CPP, whereas the PI and velocity peak-to-peak amplitude increase moderately. In a second zone (CPP between 40–45 and 70 mm Hg), in which vasodilation of small pial arteries becomes maximal, the mean velocity starts to decrease, whereas the PI and velocity amplitude continue to increase. In the third zone, in which autoregulation is completely exhausted (CPP < 40 mm Hg), arterioles behave passively, mean velocity and velocity amplitude decline abruptly, and the PI exhibits a disproportionate rise. Moreover, this rise is quite independent of whether CPP is reduced by increasing ICP or reducing mean SAP.
In contrast, in patients with defective autoregulation, the mean velocity and velocity amplitude decrease linearly with decreasing CPP, but the PI still increases in a way similar to that observed in patients with preserved autoregulation.
Conclusions. The information contained in the TCD waveform is affected by many factors, including ICP, SAP, autoregulation, and intracranial compliance. Model results indicate that only a comparative analysis of the concomitant changes in ultrasonographic quantities during multimodality monitoring may permit the assessment of several aspects of intracranial dynamics (cerebral blood flow changes, vascular pulsatility, ICP changes, intracranial compliance, CPP, and autoregulation).
Age dependency of resistance to cerebrospinal fluid outflow
Authors: Albeck Michael J. , Skak Claus , Nielsen Per R. , Olsen Karsten S. , Børgesen Svend E. , Gjerris Flemming 
Published: June 2009

Object. Resistance to cerebrospinal fluid (CSF) outflow (Rout) is an important parameter in assessing the need for CSF shunt placement in patients with hydrocephalus. The normal lower limit of Rout has been estimated on the basis of the clinical effect of shunt placement in patients with varying values of Rout and in young healthy volunteers. The lack of clinical effect from CSF shunts in some elderly patients, despite elevated Rout, suggests that the normal value of Rout increases with age and may be higher in elderly persons. The aim of the present study was to examine the relationship between Rout and age in patients without known CSF dynamic disturbances.
Methods. Fifty-two patients ranging from 20 to 88 years of age and with no known CSF dynamic disorders were examined. The Rout was measured using a lumbar computerized infusion test. The correlation between Rout and age was analyzed by performing linear regression. The Rout increased significantly with patient age. The Rout in a patient in the eighth decade will be approximately 5 mm Hg/ml/minute higher than in a young patient.
Conclusions. The present study shows a small but critical increase in Rout with increased patient age. A notable residual variation was present and borderline values of Rout should be regarded and used with caution.
Posttraumatic hypothermia in the treatment of axonal damage in an animal model of traumatic axonal injury
Authors: Koizumi Hiroyasu , Povlishock John T. 
Published: June 2009

Object. Many investigators have demonstrated the protective effects of hypothermia following traumatic brain injury (TBI) in both animals and humans. Typically, this protection has been evaluated in relation to the preservation of neurons and/or the blunting of behavioral abnormalities. However, little consideration has been given to any potential protection afforded in regard to TBI-induced axonal injury, a feature of human TBI. In this study, the authors evaluated the protective effects of hypothermia on axonal injury after TBI in rats.
Methods. Male Sprague—Dawley rats weighing 380 to 400 g were subjected to experimental TBI induced by an impact-acceleration device. These rats were subjected to hypothermia either before or after injury, with their temporalis muscle and rectal temperatures maintained at 32°C for 1 hour. After this 1-hour period of hypothermia, rewarming to normothermic levels was accomplished over a 90-minute period. Twenty-four hours later, the animals were killed and semiserial sagittal sections of the brain were reacted for visualization of the amyloid precursor protein (APP), a marker of axonal injury. The density of APP-marked damaged axons within the corticospinal tract at the pontomedullary junction was calculated for each animal. In all hypothermic animals, a significant reduction in APP-marked damaged axonal density was found. In animals treated with preinjury, immediate postinjury, and delayed hypothermia, the density of damaged axons was dramatically reduced in comparison with the untreated controls (p < 0.05).
Conclusions. The authors infer from these findings that early as well as delayed posttraumatic hypothermia results in substantial protection in TBI, at least in terms of the injured axons.
Dural cysts in the cervical region
Authors: Hamburger Christoph H. , Büttner Andreas , Weis Serge 
Published: June 2009

✓ Dural spinal cysts are exceedingly rare lesions. The authors are aware of only seven cases reported in the literature. This report comprises three patients with dural cysts of the cervical spinal canal who presented with atypical neurological signs and symptoms, including a long history of dysesthesias and atrophic pareses in the proximal upper extremities.
Surgical intervention disclosed two ventrally and one dorsally located cystic lesions of the spinal dura mater. The cystic wall was fenestrated and kept open by a silicone catheter in each case. Histological examination of the excised lesions revealed fibrous connective tissue consistent with dural tissue. No epithelial lining was detected. The lesions were classified as dural cysts. The patients' postoperative courses were uneventful.
Although dural cysts are rare lesions, they must be considered in the differential diagnosis of spinal cystic lesions. Because they are nonaggressive and can be safely drained by microsurgical techniques, patients have a favorable prognosis. Early surgical intervention is mandatory to prevent severe neurological deficits.
Endodermal cysts of the posterior fossa
Authors: Bejjani Ghassan K. , Wright Donald C. , Schessel David , Sekhar Laligam N. 
Published: June 2009

✓ The pathogenesis of endodermal cysts of the posterior fossa is still incompletely understood. The authors reviewed three new cases and those reported in the literature to clarify the clinical, pathological, radiological, and surgical characteristics of these lesions. A total of 49 cases were reviewed. Details on demographic profiles, clinical characteristics, histopathological and radiological features, and surgical methods were collected.These cysts have a predominance in male patients (61%) and can occur at any age (birth–77 years). In patients with posterior fossa endodermal cysts there is a bimodal age distribution and headache is the most frequent complaint. On immunohistopathological examination, endodermal cysts were reactive for epithelial membrane antigen and for keratin immunostains whenever the latter were tested. The cysts were reactive for carcinoembryonic antigen in nine of 11 cases. Endodermal cysts were located anterior to the brainstem in 51% of cases and in the fourth ventricle in 21% of cases. They frequently appeared hypodense on computerized tomography scans, and in five cases, the lesion was missed. The cyst's appearance on magnetic resonance imaging is variable. Resection was complete in 19 cases and partial in 11; marsupialization was achieved in two cases. Three recurrences have been reported.Total excision with preservation of neurological function should be the goal. Cranial base approaches are helpful for surgical access in selected examples of these lesions.
Long-term endocrinological follow-up evaluation in 115 patients who underwent transsphenoidal surgery for acromegaly
Authors: Freda Pamela U. , Wardlaw Sharon L. , Post Kalmon D. 
Published: June 2009

Object. The results of surgical therapy for acromegaly were assessed using carefully conducted endocrinological testing in 115 patients who underwent transsphenoidal surgery from 1981 to 1995.
Methods. Ninety-nine of the 115 patients could be contacted for follow-up review; in 57 of the patients an endocrinological assessment was performed by the authors. Biochemical cure was strictly defined as a normalization of the insulin-like growth factor(IGF)—I level (obtained in 100 patients) and/or a basal or glucose-suppressed growth hormone (GH) level of 2 ng/ml or less. The mean length of follow up from transsphenoidal surgery to laboratory testing was 5.4 years with a maximum of 15.7 years. After transsphenoidal surgery alone, 61% of the patients achieved a biochemical remission; the remission rate was 88% for patients with microadenomas and 53% for those with macroadenomas. Tumor size and preoperative GH level tended to correlate negatively with outcome of surgery. Early postoperative GH level tended to correlate with long-term outcome; in cases in which the early postoperative GH level was lower than 3 ng/ml, the chance of long-term remission was 89%. Thirty-two patients received postoperative radiotherapy: in 10 (31%) of these patients the disease is currently in remission after surgery and radiotherapy only and in three others the disease is in remission with the addition of medical therapy. The overall complication rate was 6.9% with no cerebrospinal fluid leaks, meningitis, permanent diabetes insipidus, or new hypopituitarism. The overall recurrence rate was low at 5.4%.
Conclusions. This series shows, based on IFGF—I measurements and strict GH supression criteria to define remission, that transsphenoidal surgery provides an excellent chance for long-term cure in patients with microadenomas. Surgery alone is successful in most patients with noninvasive macroadenomas; however, most patients with invasive macroadenomas will require adjunctive therapy. Recurrences are uncommon when biochemical remission is clearly documented postoperatively.
A clinical comparison of one- and two-screw odontoid fixation
Authors: Jenkins Jeffrey D. , Coric Domagoj , Branch Charles L. 
Published: June 2009

Object.The optimal treatment of Type II odontoid fractures is controversial. Various therapies have been used, including nonrigid immobilization, halo orthosis, posterior atlantoaxial arthrodesis, and odontoid screw fixation. Of these, odontoid screw fixation is the only treatment modality that provides immediate stabilization and preserves normal motion at C1–2. It has been suggested in cadaveric biomechanical studies that there is no advantage to using more than one screw for anterior odontoid fixation. The authors compared the clinical safety and efficacy of one- and two-screw anterior odontoid fixation.Methods.The authors retrospectively reviewed the medical records and radiographs of 42 consecutive patients who had undergone fixation for treatment of odontoid fractures at a single institution between 1989 and 1995.The group treated with a single screw consisted of 20 patients (11 males and nine females) with an average age of 54 years. The union rate in this group, as determined by postoperative dynamic radiographs, was 81%. The group treated with two screws consisted of 22 patients (13 men and nine women) with an average age of 64 years, whose union rate was 85%.Conclusions.Anterior odontoid screw fixation is a safe and efficacious treatment for odontoid fractures. In the authors' experience there was no significant difference in the successful union rates achieved with either the one- or two-screw fixation techniques (81% and 85%, respectively; χ2= 0.09, p = 0.76).