BACKGROUND In bow hunter’s syndrome(BHS),also known as rotational vertebral artery(VA)syndrome,there is dynamic/rotational compression of the VA producing verte-brobasilar insufficiency.Most occurrences involve atlan...BACKGROUND In bow hunter’s syndrome(BHS),also known as rotational vertebral artery(VA)syndrome,there is dynamic/rotational compression of the VA producing verte-brobasilar insufficiency.Most occurrences involve atlantoaxial rather than mid-cervical VA compromise,the latter being rarely reported.Herein,we detail successful VA decompression at mid-cervical spine,given a departure from its usual course.CASE SUMMARY The patient,a 45-year-old man,presented to our hospital with occipital headache and vertigo.Computed tomography angiography showed anomalous C4 entry of right VA,with compression upon head rotation to that side.Thyroid cartilage and anterior tubercle of C5 transverse process were visibly at fault.We opted for sur-gery,using an anterior cervical approach to remove the anterior tubercle.Patient recovery was uneventful and brought resolution of all preoperative symptoms.CONCLUSION BHS is an important consideration where aberrant coursing of VA and neurologic symptoms coexist.展开更多
The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of th...The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of the straight stator stages are investigated and compared to those of the bowed stator stages. The results show that using bowed stator stages could alleviate the flow separation at both upper and low corners of the suction surface and the endwalls, and decrease the losses along the flow passage as well as the outlet flow angle. As the rotor/stator axial gap decreases, although the diffusion capacity of the compressor increases obviously, the outlet flow field in the straight stator stages deteriorates quickly. By contrast, little changes occur in the bowed stator stages, indicating that as the rotor/stator axial gap decreases, improved performance is achieved in the bowed stator stages.展开更多
文摘BACKGROUND In bow hunter’s syndrome(BHS),also known as rotational vertebral artery(VA)syndrome,there is dynamic/rotational compression of the VA producing verte-brobasilar insufficiency.Most occurrences involve atlantoaxial rather than mid-cervical VA compromise,the latter being rarely reported.Herein,we detail successful VA decompression at mid-cervical spine,given a departure from its usual course.CASE SUMMARY The patient,a 45-year-old man,presented to our hospital with occipital headache and vertigo.Computed tomography angiography showed anomalous C4 entry of right VA,with compression upon head rotation to that side.Thyroid cartilage and anterior tubercle of C5 transverse process were visibly at fault.We opted for sur-gery,using an anterior cervical approach to remove the anterior tubercle.Patient recovery was uneventful and brought resolution of all preoperative symptoms.CONCLUSION BHS is an important consideration where aberrant coursing of VA and neurologic symptoms coexist.
基金National Natural Science Foundation of China (50646021)Chinese Specialized Research Fund for the Doctoral Pro-gram of Higher Education (20060213007)
文摘The outlet flow fields of a low-speed repeating-stage compressor with bowed stator stages are measured with five-hole probe under the near stall condition when the rotor/stator axial gap varies. The performances of the straight stator stages are investigated and compared to those of the bowed stator stages. The results show that using bowed stator stages could alleviate the flow separation at both upper and low corners of the suction surface and the endwalls, and decrease the losses along the flow passage as well as the outlet flow angle. As the rotor/stator axial gap decreases, although the diffusion capacity of the compressor increases obviously, the outlet flow field in the straight stator stages deteriorates quickly. By contrast, little changes occur in the bowed stator stages, indicating that as the rotor/stator axial gap decreases, improved performance is achieved in the bowed stator stages.
