ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

OBJECTIVEConcussion in professional football was studied with respect to impact types and injury biomechanics. A combination of video surveillance and laboratory reconstruction of game impacts was used to evaluate concussion biomechanics.METHODSBetween 1996 and 2001, videotapes of concussions and significant head impacts were collected from National Football League games. There were clear views of the direction and location of the helmet impact for 182 cases. In 31 cases, the speed of impact could be determined with analysis of multiple videos. Those cases were reconstructed in laboratory tests using helmeted Hybrid III dummies and the same impact velocity, direction, and head kinematics as in the game. Translational and rotational accelerations were measured, to define concussion biomechanics. Several studies were performed to ensure the accuracy and reproducibility of the video analysis and laboratory methods used.RESULTSConcussed players experienced head impacts of 9.3 ± 1.9 m/s (20.8 ± 4.2 miles/h). There was a rapid change in head velocity of 7.2 ± 1.8 m/s (16.1 ± 4.0 miles/h), which was significantly greater than that for uninjured struck players (5.0 ± 1.1 m/s, 11.2 ± 2.5 miles/h;t= 2.9,P< 0.005) or striking players (4.0 ± 1.2 m/s, 8.9 ± 2.7 miles/h;t= 7.6,P< 0.001). The peak head acceleration in concussion was 98 ± 28 g with a 15-millisecond half-sine duration, which was statistically greater than the 60 ± 24 g for uninjured struck players (t= 3.1,P< 0.005). Concussion was primarily related to translational acceleration resulting from impacts on the facemask or side, or falls on the back of the helmet. Concussion could be assessed with the severity index or head injury criterion (the conventional measures of head injury risk). Nominal tolerance levels for concussion were a severity index of 300 and a head injury criterion of 250.CONCLUSIONConcussion occurs with considerable head impact velocity and velocity changes in professional football. Current National Operating Committee on Standards for Athletic Equipment standards primarily address impacts to the periphery and crown of the helmet, whereas players are experiencing injuries in impacts to the facemask, side, and back of the helmet. New tests are needed to assess the performance of helmets in reducing concussion risks involving high-velocity and long-duration injury biomechanics.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BACKGROUNDStereotactic radiosurgery is the principal therapeutic alternative to resecting benign intracranial tumors. The goals of radiosurgery are the long-term prevention of tumor growth, the maintenance of patient function, and the prevention of new neurological deficits or adverse radiation effects. Evaluation of long-term outcomes more than 10 years after radiosurgery is needed.METHODSWe evaluated 285 consecutive patients who underwent radiosurgery for benign intracranial tumors between 1987 and 1992. Serial imaging studies were obtained, and clinical evaluations were performed. Our series included 157 patients with vestibular schwannomas, 85 patients with meningiomas, 28 patients with pituitary adenomas, 10 patients with other cranial nerve schwannomas, and 5 patients with craniopharyngiomas. Prior surgical resection had been performed in 44% of these patients, and prior radiotherapy had been administered in 5%. The median follow-up period was 10 years.RESULTSOverall, 95% of the 285 patients in this series had imaging-defined local tumor control (63% had tumor regression, and 32% had no further tumor growth). The actuarial tumor control rate at 15 years was 93.7%. In 5% of the patients, delayed tumor growth was identified. Resection was performed after radiosurgery in 13 patients (5%). No patient developed a radiation-induced tumor. Eighty-one percent of the patients were still alive at the time of this analysis. Normal facial nerve function was maintained in 95% of patients who had normal function before undergoing treatment for acoustic neuromas.CONCLUSIONStereotactic radiosurgery provided high rates of tumor growth control, often with tumor regression, and low morbidity rates in patients with benign intracranial tumors when evaluated over the long term. This study supports radiosurgery as a reliable alternative to surgical resection for selected patients with benign intracranial tumors.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

OBJECTIVETo evaluate treatment of essential trigeminal neuralgia with 90 Gy delivered by a linear accelerator dedicated to radiosurgery.METHODSThis is a retrospective case series of 25 patients with essential trigeminal neuralgia treated from March 1999 to March 2001. All were treated with 90 Gy by means of a 5-mm collimator directed to the nerve root entry zone. Patient follow-up (range, 8–52 mo; median, 18 mo) was completed by an uninvolved party. Dose volume histograms of the brainstem were developed for the 20, 30, and 50% isodose lines by means of radiosurgery planning software.RESULTSAll patients obtained good to excellent pain relief with treatment. Nineteen (76%) of 25 patients achieved excellent pain relief (pain-free without medication). Six patients (24%) achieved good pain relief (50–90% reduction of pain with or without medication). Median time to pain relief was 2 months. Eight patients (32%) experienced relapse 4 to 13 months after treatment. Eight patients (32%) developed facial numbness, but none developed painful numbness. Mean brainstem volume within the 50% isodose line and occurrence of numbness was statistically significant (P= 0.03). There was no correlation between brainstem volume treated and outcome.CONCLUSIONDedicated linear accelerator-based stereotactic radiosurgery that uses a 5-mm collimator to deliver 90 Gy to the nerve root entry zone is a safe and effective method for the treatment of essential trigeminal neuralgia. Care should be taken to limit brainstem volume included in the 50% isodose line in the treatment plan to avoid facial numbness.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

OBJECTIVETo describe the management and outcomes of seven patients with fusiform aneurysms of the peripheral posteroinferior cerebellar artery (PICA).METHODSMedical records and neuroimaging studies of seven patients who underwent surgical treatment of fusiform aneurysms of the peripheral PICA were reviewed. Average follow-up time was 1.5 years, and no patient was lost to follow-up.RESULTSAll patients presented with acute subarachnoid hemorrhage, and most had acute hydrocephalus. All underwent surgery, which entailed distal revascularization in six of the seven patients. Revascularization techniques included occipital artery–PICA bypass, side-to-side PICA-PICA anastomosis, and aneurysm excision with direct end-to-end PICA reanastomosis. Outcome was good in six patients and fair in one.CONCLUSIONFusiform, peripheral PICA aneurysms are rare lesions. Distal revascularization was used in most cases because of the uncertain adequacy of collateral supply. Careful, individualized management allows for a good outcome in the majority of cases.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

OBJECTIVETo evaluate findings for patients with carotid cavernous fistulae or dural arteriovenous fistulae (AVFs) who underwent transvenous embolization via different transvenous approaches.METHODSRetrospective analysis of data for 31 patients (age range, 17–81 yr; mean age, 59.3 yr) with carotid cavernous fistulae (n = 6) or dural AVFs (cavernous sinus [CS], n = 11; transverse/sigmoid sinus, n = 14) was performed. The AVFs were treated with coils via different transvenous approaches, in 56 procedures. Doppler ultrasonography and time-resolved, two-dimensional, magnetic resonance projection angiography were performed to confirm the treatment. The mean clinical follow-up period was 32.5 months.RESULTSA total of 34 transvenous procedures were performed for 17 AVFs of the CS. Eleven patients with AVFs of the CS (63%) were cured with respect to clinical symptoms, and six patients experienced improvement (37%). The approach via the internal jugular vein and inferior petrosal sinus (n = 15) was possible in 60% of cases, with complete occlusion of the fistula in 78% of cases. With the approach via the facial vein (n = 8), there was a 50% success rate. The superior ophthalmic vein approach (n = 5) was associated with a high rate of technical success (100%), with a rate of complete fistula occlusion of 80%. We encountered complications, with transient morbidity, in four cases (23.5%). For 14 dural AVFs of the transverse/sigmoid sinus, 22 transvenous procedures were performed; 12 patients were cured (85.7%) and 2 experienced improvement (14.3%). The technical success rate was 86%, with complete occlusion in 42% of cases. Minor complications occurred in six cases (42.9%) but did not lead to permanent morbidity.CONCLUSIONTransvenous treatment of CS and transverse/sigmoid sinus AVFs can be effective if all transvenous approaches, including combined surgical/endovascular approaches, are considered.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

OBJECTIVEHigh-flow, extracranial-intracranial (EC-IC) bypass operations are performed to prevent strokes among patients with giant aneurysms who cannot tolerate internal carotid artery (ICA) occlusion. However, the volume flow through the bypass, compared with preoperative ICA flow, has not been evaluated for any type of bypass. We describe a prospective case study that tested the ability of the high-flow EC-IC bypass to replace the volume flow of the ipsilateral ICA after deliberate ICA occlusion.METHODSSeven consecutive patients with giant aneurysms of the ICA who experienced test occlusion failure underwent nonocclusive, excimer laser-assisted, EC-IC bypass surgery before permanent ICA occlusion. Volume flow values in the ICAs, the basilar artery, the EC-IC bypass, and the middle cerebral arteries were measured with magnetic resonance angiography.RESULTSNo significant changes in volume flow to the ipsilateral and contralateral hemispheres were observed after bypass surgery and therapeutic ICA occlusion. Before bypass surgery, the volume flow through the ipsilateral ICA was 243 ± 74 ml/min, that through the contralateral ICA was 264 ± 32 ml/min, and that through the basilar artery was 141 ± 43 ml/min. After bypass surgery and therapeutic occlusion of the ipsilateral ICA, the volume flow through the bypass was 199 ± 72 ml/min, that through the contralateral ICA was 303 ± 82 ml/min, and that through the basilar artery was 153 ± 72 ml/min. No significant preoperative versus postoperative changes in middle cerebral artery flow were observed on either side.CONCLUSIONThe flow through the high-flow EC-IC bypass was able to replace the volume flow of the ipsilateral ICA after deliberate ICA occlusion for the treatment of giant aneurysms.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

OBJECTIVEWe sought to evaluate the sensitivity and specificity of transcranial color-coded duplex sonography (TCCS) and the effect of an ultrasonographic contrast agent in the long-term surveillance of intracranial aneurysms treated with Guglielmi detachable coils.METHODSForty-six studies were obtained in patients with intracranial aneurysms treated with coils. All studies were obtained within 2 months of surveillance digital subtraction angiograms, which was adopted as the standard for observing aneurysm refilling. For 34 of the studies, imaging was performed both before and after infusing an ultrasonographic contrast agent (Levovist). The remaining 12 studies were unenhanced. Aneurysms were described either as being fully occluded or as having residual flow. The degree of residual flow was quantified as minor, moderate, or extensive. The operator was blinded to the results of digital subtraction angiography during TCCS assessment.RESULTSTCCS correctly identified 19 of 20 aneurysms with complete occlusion (sensitivity, 95%; specificity, 84%). TCCS also identified all 16 of the clinically relevant aneurysms with either moderate or extensive residual flow visualized on digital subtraction angiograms and 5 aneurysms only after contrast enhancement (sensitivity, 100%; specificity, 97%). The overall accuracy of TCCS in identifying clinically relevant aneurysms was 85% without contrast enhancement and 96% with contrast enhancement.CONCLUSIONContrast-enhanced TCCS shows promise as a noninvasive imaging method for the surveillance of coiled intracranial aneurysms.

ISSN:0148-396X    

出版商:OVID    

年代:2003

数据来源: OVID