Background:When utilizing the retrosigmoid approach(RA),accurately identifying the transverse and sigmoid sinus transition(TSST)is a key procedure for neurosurgeons,especially in developing countries restricted by the...Background:When utilizing the retrosigmoid approach(RA),accurately identifying the transverse and sigmoid sinus transition(TSST)is a key procedure for neurosurgeons,especially in developing countries restricted by the lack of expensive devices,such as the neural navigation system and the three-dimensional volumetric image-rendered system.Before operations,a computed tomography scan is a common and cost-effective method of checking patients who suffer lesions located at the cerebellopontine angle.Therefore,we present a technique using only high-resolution computed tomography to identify the transverse and sigmoid sinus transition.Methods:This retrospective study included 35 patients who underwent retrosigmoid approach operations to resect an acoustic neurinoma with the assistance of our technique.In brief,our technique contains 4 steps:(1)All patients’1-mm,consecutive,high-resolution computed tomographic images that clearly displayed landmarks,such as the inion,lambdoid suture,occipitomastoid suture,and the mastoid emissary foramen,were investigated initially.(2)We selected two particular slices(A and B)among all of these high-resolution computed tomographic images in which scanning planes were parallel with the line drawn from the root of the zygoma to the inion(LZI).Slice A contained both the root of the zygoma and the inion simultaneously,and slice B displayed the mastoid emissary foramen.(3)Four points(α,β,γ,δ)were arranged on slices A and B,and pointαwas located at the inner surface of the skull,which represents the posterior part of the sulci of the sigmoid sinus.Pointβwas located at the outer surface of the skull,and the line connecting them was perpendicular to the bone.Similarly,on slice B,we labeled pointγas the point that represents the posterior part of the sulci of the sigmoid sinus at the inner surface and pointδas the point located at the outer surface of the skull,and the line connecting them was also perpendicular to the bone.The distances between pointβand the lambdoid suture/occipitomastoid suture and between pointδand the mastoid emissary foramen were calculated for slices A and B,respectively.(4)During the operation,a line indicating the LZI was drawn on the bone with ink when the superficial soft tissue was pushed away,and this line would cross the lambdoid suture/occipitomastoid suture.With both the crosspoint and the distance obtained from the high-resolution CT images,we could locate pointβ.We also used the same method to locate pointδafter revealing the mastoid emissary foramen.The line connecting pointβand pointδindicated the posterior border of the sigmoid sinus,and the intersection between the line and LZI indicated the inferior knee of the transverse and sigmoid sinus transition(TSST).Results:All 35 patients underwent the RA craniectomies that were safely assisted by our technique,and neither the sigmoid sinus nor the transverse sinus was lacerated during the operations.Conclusion:Our cost-effective technique is reliable and convenient for identifying the transverse and sigmoid sinus transition(TSST)which could be widely performed to guarantee the safety of RA craniectomy.展开更多
Objective:to compare the methods of petrous apical bone removal and to explore the applicable scope of Kawase approach and retrosigmoid sinus-internal auditory canal approach.Methods:one group of cadaveric head specim...Objective:to compare the methods of petrous apical bone removal and to explore the applicable scope of Kawase approach and retrosigmoid sinus-internal auditory canal approach.Methods:one group of cadaveric head specimens simulated Kawase approach to measure the data of“Kawase triangle”,the other group simulated retrosigmoid sinus-internal auditory canal approach to measure the safety range of the grinding bone window.Then we explored the clinical indications of the two surgical approaches.Result:the grinding depth of Kawase triangle was 11.6±0.14 mm,and the range of clival exposed after grinding Kawase triangle was 22.4±1.22 mm,which could effectively expose the ventrolateral brainstem,the midline of clivus and the area above the facial acoustic nerve.The diameter of the anterior and posterior of the grinding bone window in the retrosigmoid sinus-internal auditory canal approach was 21.95±2.23 mm.In front of the exposure area were the internal carotid artery,the cavernous sinus,and the upper trigeminal nerve;the lower part was the connection between the facial acoustic nerve and the abducent nerve.Conclusion:Kawase approach is suitable for lesions of ventrolateral brainstem,middle superior clivus,with or without invasion of middle cranial fossa;the retrosigmoid sinus-superior internal auditory canal approach is suitable for lesions mainly in cerebellopontine angle area and only slightly invading Meckel’s cavity.展开更多
文摘Background:When utilizing the retrosigmoid approach(RA),accurately identifying the transverse and sigmoid sinus transition(TSST)is a key procedure for neurosurgeons,especially in developing countries restricted by the lack of expensive devices,such as the neural navigation system and the three-dimensional volumetric image-rendered system.Before operations,a computed tomography scan is a common and cost-effective method of checking patients who suffer lesions located at the cerebellopontine angle.Therefore,we present a technique using only high-resolution computed tomography to identify the transverse and sigmoid sinus transition.Methods:This retrospective study included 35 patients who underwent retrosigmoid approach operations to resect an acoustic neurinoma with the assistance of our technique.In brief,our technique contains 4 steps:(1)All patients’1-mm,consecutive,high-resolution computed tomographic images that clearly displayed landmarks,such as the inion,lambdoid suture,occipitomastoid suture,and the mastoid emissary foramen,were investigated initially.(2)We selected two particular slices(A and B)among all of these high-resolution computed tomographic images in which scanning planes were parallel with the line drawn from the root of the zygoma to the inion(LZI).Slice A contained both the root of the zygoma and the inion simultaneously,and slice B displayed the mastoid emissary foramen.(3)Four points(α,β,γ,δ)were arranged on slices A and B,and pointαwas located at the inner surface of the skull,which represents the posterior part of the sulci of the sigmoid sinus.Pointβwas located at the outer surface of the skull,and the line connecting them was perpendicular to the bone.Similarly,on slice B,we labeled pointγas the point that represents the posterior part of the sulci of the sigmoid sinus at the inner surface and pointδas the point located at the outer surface of the skull,and the line connecting them was also perpendicular to the bone.The distances between pointβand the lambdoid suture/occipitomastoid suture and between pointδand the mastoid emissary foramen were calculated for slices A and B,respectively.(4)During the operation,a line indicating the LZI was drawn on the bone with ink when the superficial soft tissue was pushed away,and this line would cross the lambdoid suture/occipitomastoid suture.With both the crosspoint and the distance obtained from the high-resolution CT images,we could locate pointβ.We also used the same method to locate pointδafter revealing the mastoid emissary foramen.The line connecting pointβand pointδindicated the posterior border of the sigmoid sinus,and the intersection between the line and LZI indicated the inferior knee of the transverse and sigmoid sinus transition(TSST).Results:All 35 patients underwent the RA craniectomies that were safely assisted by our technique,and neither the sigmoid sinus nor the transverse sinus was lacerated during the operations.Conclusion:Our cost-effective technique is reliable and convenient for identifying the transverse and sigmoid sinus transition(TSST)which could be widely performed to guarantee the safety of RA craniectomy.
文摘Objective:to compare the methods of petrous apical bone removal and to explore the applicable scope of Kawase approach and retrosigmoid sinus-internal auditory canal approach.Methods:one group of cadaveric head specimens simulated Kawase approach to measure the data of“Kawase triangle”,the other group simulated retrosigmoid sinus-internal auditory canal approach to measure the safety range of the grinding bone window.Then we explored the clinical indications of the two surgical approaches.Result:the grinding depth of Kawase triangle was 11.6±0.14 mm,and the range of clival exposed after grinding Kawase triangle was 22.4±1.22 mm,which could effectively expose the ventrolateral brainstem,the midline of clivus and the area above the facial acoustic nerve.The diameter of the anterior and posterior of the grinding bone window in the retrosigmoid sinus-internal auditory canal approach was 21.95±2.23 mm.In front of the exposure area were the internal carotid artery,the cavernous sinus,and the upper trigeminal nerve;the lower part was the connection between the facial acoustic nerve and the abducent nerve.Conclusion:Kawase approach is suitable for lesions of ventrolateral brainstem,middle superior clivus,with or without invasion of middle cranial fossa;the retrosigmoid sinus-superior internal auditory canal approach is suitable for lesions mainly in cerebellopontine angle area and only slightly invading Meckel’s cavity.
