Microanatomical Study Of The Minicraniotomy Transpetrosal Ridge Approach To The Petroclival Region

Objective According to partial lateral operation approach in petroclival region, to investigate the feasibility and the microsurgical anatomy of the minicraniotomy transpetrosal ridge approach to the petroclival region. Make the operation a good exposing with simple, safe, practical and minimal invasive character, reduce postoperative complications.Methods 1. The use of 10 cases (20 sides) do skull specimens by a small bone window petrous bone crest approach involving relevant anatomical structure observation, measurement, guidance during the grinding petrous bone and exposing petroclival region. 2. The use of 10 cases (20 sides) skull wet specimens, the use of Micro-neurosurgery technology, carried out by ear on rock ridge of bone with small bone window approach to petroclival region. I select the baseline level of the external auditory canal on 0.5cm, auricle front 0.5cm, about 4.0cm from the vertical upward parallel arc slightly backward, over-ear fate again after the next vertical stop near stars, generally show transverse sinus fate, blunt separation of temporal muscle flap and turned under. External auditory canal by milling off the top of one 4×3cm in diameter about the size of bone window, to further grind the surface of the part of some of mastoid bone to the proximal petrous bone skull ridge intersection. Under the microscope inverted "Y"-shaped incision of dura mater and free, suspension, taking temporal lobe lightly and observe Labbe vein and its anastomosis, the appropriate concept to further free the vein of its morphology and in tentorial injection point on, if necessary, cut off small branch of its front in order to increase exposure. Labbe vein plate away from the brain and lift temporal lobe at the bottom of about 1.5 ~ 2.0cm, can be effectively exposed petrosal ridge and intersection of internal and dural skull base, along the ridge running and show clinoid process outside the cavernous sinus after lateral area, show the tentorial notch and part of screen. From the petrous bone crest tentorial incision line arc and the former turned to observe the trochlear nerve running; Trigeminal nerve root lateral petrous bone ridge in front of 0.8-1.0cm Department dural incision, exposed petrosal ridge and internal auditory ridge. Petrosal ridge is divided into three parts with IAC: medial, between the department, lateral; Grinding the medial firstly, slopes exposed to the brain stem ventral region; Then the lateral, exposed surface acoustic neuroma and cerebellopontine angle; and finally grinding the exception of two minor petrous bone between the crest (control at less than 3mm), an increase of the petrous bone showing the dorsal region. Analyze the operating spaces of provided by the extradural procedure and measure the important data of the main anatomic structure.Results (1) Labbe vein: 16 in the side, such as lack of side 4, one-branch 4, double-branch 5, multi-branch 7; Labbe vein were observed in 37: Transverse sinus group25, tentorial group10, rock group1, over-transverse sinus group1. (2) The measured distance and record: Cochlea from the V root 11.62±2.04mm, semicircular canal from the sigmoid sinus 10.90±1.26mm; The distance for petrosal ridge: IV into the point tentorial 4.79±0.97mm, rock hole of greater superficial petrosal nerve(GSPN) 13.36±2.27mm, internal carotid artery above the level of petrous bone11.38±2.46mm, retrocochlear fate7.58±1.22mm, drum after sinus7.00±1.30mm, half-point regulation4.67±1.42mm, tympanic segment of facial nerve9.23±1.99mm. (3) Anatomy of observation:The minicraniotomy transpetrosal ridge is relatively easy approach to the skull base, by the petrous bone crest to the road through the temporal lobe lift, may well be revealed in the sellar region lateral skull base, brain stem ventral, lateral , petroclival region in the upper part; Tentorial incision through further and grinding part of petrous bone in addition to increase in the slope crest lateral, dorsal petrous bone and cerebellopontine angle exposure ,can be a good lateral skull base revealed the above-mentioned regional nerves, blood vessels and other anatomical structures.Conclusions The expose of minicraniotomy up-ear transpetrosal ridge approach is similar with subtemporal anterior transpetrosal approach(Kawase), partial labyrinthectomy petrous apicectomy approach(PLPA) and transpetrosal presigmoid approach. It allows the operation simple and minimal invasive.