| Part ⅠAnatomical Study of Skull Base Exposure Through Subtemporal Keyhole Approach Under Complete EndoscopeObjective:A feasibility study was conducted to investigate the exposure and operation of the anterior,middle,and posterior skull base in various directions using the subtemporal keyhole approach through neuroendoscopy.The study adhered to the principle of minimally invasive surgery and aimed to explore the advantages and disadvantages of the neuroendoscope combined with the keyhole technique for the subtemporal approach.Additionally,the study aimed to provide an anatomical and theoretical basis for clinical surgery.Methods:Eight adult specimens were used in this study to simulate the visual field of the skull base from different directions using the subtemporal keyhole approach under the neuroendoscope.The specimens were perfused prior to the study.The adjacent relationships and distances with important blood vessels and nerves were recorded and objectively analyzed to explore the localization marks and surgical indications of this approach in endoscopic neurosurgery.In addition,the clinical data and surgical outcomes of two patients with dumbbell trigeminal neurinoma who underwent the subtemporal keyhole approach using neuroendoscope were retrospectively analyzed.The advantages of this approach were also discussed.Results : The subtemporal keyhole approach through neuroendoscope enables clear exposure of the middle and posterior cranial fossa and a portion of the anterior skull base.By adjusting the orientation of the neuroendoscope,a small bone window of2.5cm can be utilized to access important anatomical structures such as the posterior clinoid process,oculomotor nerve,superior segment of the internal carotid artery clinoid process,trochlear nerve,anterior choroidal artery,Meckel’s cavity,superior cerebellar artery,trigeminal nerve,and posterior communicating artery,as provided by the traditional subtemporal approach.Moreover,this approach offers a more intuitive observation of multiple anatomical structures such as the superior petroclival region,suprasellar region,tentorial notch space,and ventrolateral area of the brain stem through a deep and narrow tissue space.The successful resection of two cases of dumbbell trigeminal neurinoma through this approach has been reported,with fast postoperative recovery and no significant complications.Conclusions : The utilization of the neuroendoscope via the subtemporal keyhole approach offers distinct advantages in terms of anatomical exposure and surgical flexibility for accessing the middle and posterior skull base,as well as a portion of the anterior skull base.The integration of neuroendoscopy with keyhole technology enables optimal visualization and manipulation of lesions located in the petroclival region,cavernous sinus region,and ventrolateral brain stem lesions.This approach presents a promising alternative for surgical management of skull base lesions.Part ⅡQuantitative Anatomical Study of The Exposure of the Posterior Cranial Fossa Through the Subtemporal Keyhole Approach and the Intradural Subtemporal Petrosal ApproachObjective:This study conducts a comparative analysis of the exposure of the posterior cranial fossa utilizing distinct skull base assisted techniques.Specifically,the neuroendoscope-assisted subtemporal keyhole approach and microscope-assisted intradural subtemporal anterior petrosal approach are examined to determine if the intradural subtemporal approach can successfully complete the exposure and operation of the microscope-assisted intradural subtemporal anterior petrosal approach.The study further considers the advantages,disadvantages,and indications of both approaches for the operation of the posterior cranial fossa.Methods:In this study,we conducted a comparative anatomical analysis of two surgical approaches-the subtemporal keyhole approach using the neuroendoscope and the intradural subtemporal petrosal approach using the microscope.To achieve this,we utilized eight adult cadaver skulls(16 sides),fixed with formalin,to simulate the procedures.Our primary objective was to observe the relevant anatomical structures,measure the exposure boundary and operation range of the two approaches in different directions of the brain stem,and statistically analyze the differences in measurement data.We then proceeded to summarize the advantages and disadvantages of the endoscopic approach via the subtemporal keyhole.Our findings provide valuable insights into the feasibility and efficacy of these surgical techniques for treating conditions that require access to the subtemporal fossa.Results:The anatomical structures of the petroclival and ventrolateral regions of the brainstem can be effectively visualized using two surgical approaches: the intradural subtemporal anterior petrosal approach with a contrast microscope and the subtemporal keyhole approach with a neuroendoscope.By comparing the contrast and operative boundaries of these approaches,we found that the average exposure distance of the subtemporal keyhole approach under the neuroendoscope was higher than that of the intradural subtemporal petrosal approach under the microscope(P < 0.05)in the upper,lower,and ventral regions of the brainstem.The average operating distance of the subtemporal keyhole approach under the neuroendoscope was also greater than that of the intradural subtemporal petrosal approach under the microscope(P < 0.05)in the upper and ventral regions of the brainstem.However,after removing part of the petrous bone through the intradural subtemporal anterior petrosal approach,the microscope provided a larger operating space under the brainstem(P < 0.05)with a statistically significant difference.Notably,the average exposure and operating distances of the two approaches at the dorsal side of the brainstem were not statistically different.Conclusions:By adjusting the neuroendoscope in various directions,the structure of the posterior cranial fossa can be exposed optimally,providing advantages in accessing and operating on the upper,ventral,and dorsal aspects of the brainstem.Additionally,the intradural subtemporal anterior petrosal approach,which involves removing part of the petrous bone,can significantly increase the exposure and operation space beneath the brainstem.This approach is particularly suitable for treating lesions such as those affecting the basilar artery,vertebral artery,distal anterior inferior cerebellar artery,and those involving the invasion of the petrous bone. |
