Anatomy And Clinical Application Study Of Subtemporal Transtentorial Approach

PartⅠ Anatomy of bony structures in exposed areaObjective: Observaing the important bony structure of the temporal bone and the rock bone and looking for keypoints of the temporal occipital craniotomy to explore the way to locate the important anatomieal struetures in exposed area.Methods: O n 15 cases(30sides) skull specimens, we observed the shape and position of sigmoid sinus groove and the landmark of sigmoid sinus curve corner in extracranial. Foramen lacerum, hiatus canalis and internal auditory foramen and the relationship between the surrounding’s structure were observed. the distance of them were measured.Results: Asterion was all in the behind of transverse-sigmoid sinus.The coincidence rate of anterior horn of parietomastoid suture and sigmoid sinus sulcus upper curved corner was 76.67%(23/30). The distance between Mastoid crest on the backend high seam and anterior horn of parietoma stoid suture was(10.34 ± 0.62) mm, The distance outer edge of Foramen lacerum away from the arcuate eminence highest point was(34.98 ± 1.67) mm, the distance to trigeminal nerve center for rock sharp pressure trace was(6.98 ± 1.09) mm, The distance between hiatus canalis facialis and arcuate eminence highest point was(14.67 ± 1.74) mm, the distance to petrous ridge was(11.67 ± 1.24) mm, The distance between internal auditory foramen trailing edge and arcuate eminence peak was(15.31 ± 1.78) mm, The distance between internal auditory foramen leading edge and foramen lacerum peripheral was(16.36 ± 1.70) mm.Conclusions:Asterion was not appropriate for the judgment sign of transverse-sigmoi-d sinus judgment sign. Anterior horn of parietomastoid suture with sigmoid sinusgroove on the curved angle on the position was consistent, it can used as key points for the temporal and occipital craniotomy. Anterior horn of parietomastoid suture generally located behind the rear of mastoid crest ridges on the back end about 1 cm. We can use arcuate eminence and petrous ridge to locate hiatus canalis facialis.use arcuate eminence and trigeminal rock tip pressure trace center to locate foramen lacerum, use arcuate eminence and Foramen lacerum periphery to locate internal auditory foramen.PartⅡ Anatomy and Relationship of important blood vessel and nerve in exposed areaObjective:To observe the important vessels of operation approach including Labbe veins,posterior cerebral artery, superior cerebellar artery,the petrosal vein and the distribution of nerve including oculomotor nerve, trochlear nerve,trigeminal nerve, To find the important anatomic landmark of the trochlear nerve in exposed area, measurement the important relationship between blood,vessels and nerve and tentorium of cerebellum.Methods:Subtemporal transtentorial approach of operation in 10cases(20sides) adult cadaveric heads,to observe the morphology and shape of Labbe vein, preliminary observation the relationship between vascular and nerve of lateral regions of tento-rium cerebelli hiatus. sawn and remove the calvaria along the connection of upper edge of the eyebrow and 1cm upon the external occipital protuberance. remove brain tissue above the level of the tentorium cerebelli hiatus for observation of relationship between the regional vascular, nerve and tentorium of cerebellum. Measurement the distance between anterior, posterior clinoid process and the trochlear nerve into the tentorium cerebelli hiatus.Results: The cases of single type of Labbe veins was 11(55%), the cases of double root type was 6(30%), the cases of multiple type was 3(15%). The distance between Labbe veins into the transverse sinus and STP(transverse sinus, sigmoid sinus, superior petrosal sinus junction) was(24.60 ±5.82) mm; the trochlear nerve length of the segment of cisternal was(34.25± 2.58) mm, the length under the tentorium of cerebellum was(6.64± 1.82) mm. The trochlear nerve into the tentorial incisures from the after the foreign party of posterior clinoid process was(15.50 ±3.85) mm, the distance between the veins into the superior petrosal sinus and Meckel capsule was(10.50±2.42) mm. the cases of the superior cerebellar artery lower than tentorial incisures level was 16(80%). Ring pool section of the posterior cerebral artery was located above the tentorial incisures in 17 cases(85%).Conclusions: Labbe veins had an important function of the drainage, and the drainage point location determines the application of the operation of subtemporal transten-torial approach. Incision of tentorium cerebelli behind the posterior clinoid process 17.5 mm was safe. For the protection of the petrosal vein, ligation of superior petrosal sinus should be near to the trigeminal Meckel sac sideas as close as possible, should be less than 1 cm. In most cases, superior cerebellar artery located above the tentorium of cerebellum, posterior cerebral artery located below the tentorium of cerebellum.PartⅢ Clinical application of Subtemporal Transtentorial ApproachObjectives: On the basic anatomical studies of the important structure in the exposed area through subtemporal transtentorial approach for clinical application, to explore the advantages and considerations of this operation approach for resection ofpetroclival lesions, and summarize the experience of clinical application.Methods: Between October 2011 and October 2014, 20 cases of petroclival lesions were treated and resected with the operation through subtemporal transtentorial approach including meningiomas, trigeminal schwannoma and epidermoid cyst. Through the analysis of treatment effect, intraoperative considerations are discussed.Results: 16 cases of the 20 patients were total resected(80%), 3 cases were subtotal resected(15%), partial resection in 1 case(5%). 6 cases of trigeminal schwannoma were recovered well postoperatively, new trigeminal nerve d isfunction occured in 1 case, and postoperative neurological d isfunction in 1 case. Lateral temporal lobe hematoma with operation side was occurred in 1 case of the 12 meningioma patients after operation, transient aphasia occurred in 2 patients which the lesions were located on the left side, and 1 case of patients occurred with intracranial infection postoperative, were recovered well after active treatment. All 20 patients were followed up postoperatively, 6 cases of trigeminal schwannoma and 2 patients with epidermoid cyst were recovering well, 1 case left with ipsilateral facial numbness. In 12 patients with meningioma, 2 cases were left with peripheral facial paralysis, and 1 case was left with diplopia symptom. Brain MRI showed for subtotal tumor patients with postoperative tumor is increased, the remaining patients had no signs of recurrence of the tumor.Conclusion: Subtemporal transtentorial approach resection for lesions in petroclival region and tentorium hiatus area possess the advantage over other approach. To focus on the protection of the temporal lobe, Labbe vein and the trochlear nerve intraoperative. The protection of important structures should take into account in tumor resection based on full- cut as far as possible, to improve the quality of patients life.