| The microanatomy of the region of petroclivalObjective:Because of the deep location of the petroclival, in which area the relationship of the vessels and nerves is complicated. So, the surgical operation in this area is challenging. The aim of this experiment is to study the relationship of the vessels and nerves, and the coursing features. It is the objective that to provide the basis for the study of microscopic anatomy of the lateral surgical approach into the petroclival region.Materials and Methods:We use 8 cases arterial perfusion by red latex adult cadaver specimens, and removal of brain tissue, then use microscope with 4-15 times to simulate side approaches from different directions.To research the important nerves, blood vessels in petroclival Traveling and relationship with petrous bone.To further clarify the distribution of important structures within the petrous bone. Make sure the microanatomy relationship of the nervous, vascular and the relationship with the surrounding important microstructure, and then detailed records of anatomical data.Results:the petroclival region is composed of petrous bone and rock slope. One of important anatomical structures is petrous bone, around which include important anatomy structure:osseous labyrinth、cochlea, semicircular canal. The shortest distance of the Meckel’s cave at the outer edge and the cochlea was 11.26 ± 0.32 (9.12-13.84) mm; cochlea to geniculate ganglion distance was 3.53 ± 0.37 (1.76-3.04); cochlea to the petrous segment of internal carotid artery at the distance was 2.76 ± 0.54(2.08-3.28)mm. New method to locate the cochlea with three points: the medial margin of internal acoustic canal; the genu of facial nerve; A point (the point at outer 1/3 of the line between the intersection of greater superficial petrosal nerve and mandibular nerve and geniculate ganglion). The petrous segment of internal carotid artery was next to the greater superficial petrosal nerve.The length of the petrous segment was about (6.24 ± 1.60) mm, horizontal section length was about (12.20 ± 4.26) mm. The petrous segment of internal carotid artery was covered with a dense sympathetic nerve plexus, on the surface of which the thickness of bone was different, even absent. The veneous sinus behind petrosal bone was in much variation, lack of inferior petrosal sinus in 1 side was found in the samples, and found that many sinus anastomosis between the superior inferior petrosal sinus. The facial nerve issued from the brainstem, then is divided into 5 sections:the first paragraph is the intracranial section, about 12.34～14.46mm; the second paragraph is internal auditory canal, approximately 7.46～9.12mm; the third paragraph is the labyrinthine segment, about 3.22～fourth 4.24mm segment is a horizontal section, about 8.04～12.26mm, which was apt to be damaged in the operation easily. The fifth section is vertical section, about 15.84～20.06mm, which was running in the mastoid air chamber. The subdural structural in rock slope was divided into three parts:the upper, middle and lower. ①The upper part of this region:including the trochlear nerve, trigeminal nerve, posterior cerebral artery, superior cerebellar artery, basilar artery. Oculomotor nerve length was 16.62 ± 2.16mm. The distance of between the point that trochlear nerve pass through the free edge of the tentorium and petrous apex was about 1.32 ± 0.78mm. There are 2 cases of embryonal posterior cerebral artery in this group of specimens. ②The middle region:including the basilar artery and anterior inferior cerebellar artery, which is near the Ⅴ, Ⅵ, Ⅶ, Ⅷ cranial nerve closely. The anterior inferior cerebellar artery arose from the basilar artery lower thirds.In the specimens, we found 1 side double stem anterior inferior cerebellar artery, basilar artery inclined to one side of the specimen were obviously, on the other side of the anterior inferior cerebellar artery was slim. ③The lower part of the area:including glossopharyngeal nerve, vagus, hypoglossal nerve. And with the posterior inferior cerebellar artery, vertebral artery, basilar artery close,2 lateral posterior inferior cerebellar artery were missing in this group.Conclusion:① There were many vessels、nerves within the petroclival area,in which region the relationship is complicated. Grasping the microscopic anatomy of petroclival region is the basement of operation properly in this region and reduce the postoperative complications.②Due to the relationship of the position of top of the basilar artery and posterior clinoid process is important to the basilar artery aneurysm operation approach, so it should be make clear both preoperative position. ③In posterior fossa adjacent multiple vasculars and nerves compose neurovascular complex,, which should be protected in operations according to the location of the lesion. ④Cochlea is the important organs of hearing in middle cranial fossa. It is easily damaged in the operation of removal the petrosal process, so we should avoid touching it in the middle cranial fossa operation. In this paper, the new method of positioning cochlea, can reduce the damage it, and maximize the removal of bone in approach channel, provide greater surgical operation fieldMicrosurgical anatomy and clinic application of the modified subtemporal anterior transpetrosal approachObjective:Subtemporal anterior transpetrosal approach is also known as "Kawase" approach, is a classic epidural lateral approach. In this experiment, we summarized its advantages, and modified it on the basis, to explore the feasibility of modified approach to the rear of sellar region, middle cranial fossa, petroclival lesions operation under a microscope. To explore the exposure scope of approach, manipulation key points in operation. To explore the difficulties of approaches and operation indication, in order to improve the level of the operation, to provide anatomical basis for the operation, reduce the possible operation complications.Materials and methods:We used 8 cases of arterial perfusion by red latex adult cadaver specimens, under microscope with 4-15 times, simulated operation approach according to the method of the modified subtemporal anterior transpetrosal approach. We observed the exposed surgical field under microscope, and identified the anatomic landmarks, and measured the distance between various anatomical landmarks:tentorial marginal, trochlear nerve, posterior cerebral artery, internal carotid artery, the maximum length of exposure of basilar artery and brainstem front, the distance of suprasellar region the highest observation point to the posterior clinoid process vertex, length of bedrock fissure, exposure area of tentorium of cerebellum in operation visual. Statistical analysis was made to measure.Results: ① all specimens were showed the free edge of the tentorium, supraclinoidal segment of internal carotid artery and its branches, the trochlear nerve, trigeminal nerve, oculomotor nerve, posterior pituitary stalk, optic chiasm, front and rear upper clinoid, basilar artery and its branches. ②Cutting off the zygomatic arch, can make the operation of sight and the base of middle cranial fossa in same line, can increase the exposure on the optic tract, the rear area of optic chiasma, and the base of the three ventricle. ③Labbe’s vein is also called the inferior anastomotic vein, is the venous anastomosis between the celebral middle vein and the transverse sinus in the brain. In this study, Labbe’s vein alone 7 sides,5 sides double stem, candelabra type accounted for 2 sides, multi branches type 2 sides,2 sides injection into tentorial sinus, 1 case into the sigmoid sinus, the others into the transverse sinus. The diameter in the ipsilateral Labbe’s vein is quite different.In the study on the left 1.02 ± 0.64mm (0.42～2.9mm), the right side was 0.92 ± 0.72mm (0.7～2.52mm), the diameter of left and right sides of no significant difference (p>0.05). Prior to the Labbe’s vein into the sinus, it sneak in intradural for a distance, which the length of them was different, in our spcimens, an average was about 2.04 ± 1.72mm (0.24～5.68mm). ④ Kawase triangular is a diamond structure, determined by four points:a petrous ridge trigeminal impression trailing edge; b intersection of superior semicircular canal extension line with the petrous ridge; c The intersection of superior semicircular canal extension line with the greater superficial petrosal nerve;d intersection of mandibular nerve and greater superficial petrosal nerve. By grinding Kawase triangle, can reveal the petroclival region above the superior petrosal sinus, especially suitable for the tumor in the upper and middle slope region, and to screen the situation of the tumor invading the middle cranial fossa and supratentorial region. The area of Kawase triangle in this group of specimens is about 2.5cm2. ⑤ Open the tentorium of cerebellum, reveal the supraclinoidal segment of internal carotid artery and its branches (posterior communicating artery and anterior choroidal artery), anterior clinoid process, posterior clinoid process, oculomotor nerve, trochlear nerve,the rear of optic chiasma, the upper part of pituitary stalk, the upper segment of the basilar artery and its branches (The superior cerebellar artery and posterior cerebral artery P1-P2 segment), the pons and midbrain ventral lateral structure. And the distance of the top of the basilar and dorsum sellae was 3.46 ± 4.62 (-7.12-5.32) mm. ⑥point B and the trochlear nerve into the tentorium of cerebellum at a distance of 1.96± 0.72(0.24～3.68) mm, and the former is the intersction of the extension line of supramastoid crest above the external canal and foramen spinosum to the margin of the tentorium of cerebellum.Conclusion:The modified subtemporal anterior transpetrosal approach for sellar rear, tentorial incisura, pre pontine cistern, petroclival region, ventral brain stem has good exposure. It can achieve the maximum range of exposure, with minimal brain damage and complications. Not only resecting the lesion, but also avoiding the peripheral vascular, nerve damage, protecting the normal physiological function of brain tissue. Therefore, we believe that the modified subtemporal anterior transpetrosal approach is one of the best approach to solve the above regional disease. ① Modified subtemporal anterior transpetrosal approach to petroclival lesions showed very good, the range of exposure on the slope in the uppe、middle part, lateral side to internal auditory canal, anterior to posterior part of cavernous sinus, posterior to the rear 2/3 of the free edge of the tentorium. ② Cutting off the zygomatic arch increase the operation view to petroclival region 12 degrees. ③ Labbe’s vein cortex section, intradural segments free, can increase the degree of temporal lobe up about 1cm. ④ Modified subtemporal anterior transpetrosal approach is mainly through the subdural grinding Kawase’s triangular bone, get exposure to petroclival region. ⑤ Modified subtemporal anterior transpetrosal approach to the upper 2/3 petroclival region has many advantages: operation distance is short, resecting the base of tumor firstly, reducing the damage on cochlear. ⑥ Modified subtemporal anterior transpetrosal approach is an effective choice of top of the basilar artery aneurysm, can effectively reveal the aneurysm neck, avoiding perforating artery injury.⑦ The new positioning method facilitates location the point of the trochear nerve into the tenturium cerebellum.Microsurgical anatomy and clinic application of the keyhole subtemporal approachObjective:The keyhole subtemporal approach is refined from classic subtemporal approach. We observe the region of suprasellar and petroclival with endoscope and microscope. We explore the exposure scope of keyhole subtemporal approach in this study, in order to improve the level of the operation, to provide anatomical basis for the operation, reduce the possible operation complications.Materials and methods:We used 5 cases of arterial perfusion by red latex adult cadaver specimens, simulated operation approach according to the method of the keyhole subtemporal approach under endoscope and microscope. We observed the exposed surgical field under endoscope, and identified the anatomic landmarks, and measured the distance between various anatomical landmarks:tentorial marginal, trochlear nerve, posterior cerebral artery, internal carotid artery, the maximum length of exposure of brainstem. Statistical analysis was made to measure.Results:① all specimens were showed the free edge of the tentorium, supraclinoidal segment of internal carotid artery and its branches, the trochlear nerve, trigeminal nerve, oculomotor nerve, rear of optic chiasm, upper part of pituitary stalk, posterior clinoid process, basilar artery and its branches.②The space of oculomotor nerve-posterior communicating artery:the length of exposure of oculomotor nerve is 12.15±2.26 (7.26-23.31) mm, the posterior communicating artery branches is 4-12. ③The space of internal carotid artery - posterior communicating artery:exposure length of internal carotid artery is 7.76±2.42 (5.20-10.51) mm. ④ The space of posterior cerebral artery - thalamic perforating arteries:the exposure length of the posterior cerebral artery is 8.34± 1.15 (6.34-11.23) mm. ⑤Refined subtemporal keyhole approach reveal the length of optic nerve is 11.95±0.72(8.23～13.68)mm, the width of the midbrain was 6.96±0.72(5.24～8.67)mm.Conclusion: ① Subtemporal keyhole approach in small bone window, using endoscope can show lesions in the rear of optic chiasmane and petroclival region.② It is urgent that clear positioning lesion before operation, and familiaring with microanatomy of the subtemporal keyhole approach, for which revealed the petroclival lesions better. ③ It will play a better role in which the endoscope cooperate with other micro technology... |
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