The Study On Microanatomy Of Basilar Artery And Clinical Application

Objective:1.To study the microanatomy of basilar artery(BA) and its variation, find out the relations between the BA with neighboring skull、nerve and provide anatomical bases for clinical operations in this area such as aneurysms and intervention operation.2.To imitate approaches to the BA, describe each approach’s exposure and provide anatomical bases for clinical approaches option.3.To analyze the information of symptomatic BA stenosis, find out the clinical characters of patients with BA stenosis and technical characters of angioplasty and stenting, evaluate the efficiency of stenting.Methods:l.The BA of20adult cadaveric specimens which perfused with silicone were dissected under the microscope, the BA length、diameter course、numbers of perforator artery and variation were measured and recorded.2.The specimens were operated by using orbitozyogmatic(OZ) approach、extended middle fossa approach and presigmoid approach.The exposure of each approach were described.3.33patients with symptomatic basilar stenosis were treated by Wingspan stent-assisted angioplasty. Technical success rate, the degree of stenosis,periprocedural neurological complications and efficiency were observed, technical characters of angioplasty and stenting were analyzed and the efficiency of stenting were evaluated. Results:1.The mean length of BA was31.35±5.73mm;the mean diameter of the upper BA was3.90±0.65mm、the lower BA was4.49±0.71mm; the mean number of left pontine perforator was5.25±1.48、right pontine perforator was5.15±1.69;the number of BA courses in the middle was12、course in the left side was6and in the right side was9;12BA apexes were above dorsum sellae,5were below and3were at the same level, the mean distance was2.75mm above the dorsum sellae.2. The mean length of P1segment of left posterior celebral artery(PCA) was5.49±1.45mm, the mean diameter of P1segment of left PCA was3.50±0.71mm; The mean length of P1segment of right PCA was5.18±1.53mm, the mean diameter of P1segment of right PCA was3.46±0.57mm;the number of perforator artery of PI segment of PCA was4.50±1.28; the mean diameter of left posterior communicating artery(PComA) was1.97±0.87mm, the mean diameter of right PComA was1.97±1.12mm.3.The OZ approach provide multiple angles to expose the BA apex, the exposure was enlarged by drilled away anterior clinoid process(ACP)、posterior clinoid process(PCP)、 elevated internal carotid artery (ICA) and oculomotor nerve and cut the tentorium of cerebellum.4.Through the extended middle fossa approach we can expose the middle segment of BA, the exposure was enlarged by cut the tentorium of cerebellum anteriorly and drilled away the labyrinth.5. Through the presigmoid approach we can expose the lower segment of BA, the exposure was enlarged by drilled away the labyrinth.6. The most symptom of BA stenosis is repeated dizziness, and the most stroke is pontine infarction, followed by cerebellar infarction. Hypertension、 diabetes、coronary heart disease、hyperlipidemia and smoking are the most frequent risk factors.7.33patients were implanted33Wingspan stents. The technical success rate was100%. The mean degree of stenosis decreased from (81.8±8.2)%before the procedure to (12.7±8.1)%after stenting.2patients(6.1%) occurred pontine infarction caused by perforator strokes. Follow-up shows3patients had new symptom of dizziness. One patient occurred pontine infarction revealed excellent and the other one revealed well.Conclusion:1.The summary of the microanatomy characters of BA provide the anatomical bases for BA approaches and interventional therepy.2. The OZ approach provide multiple angles to expose the BA apex, the exposure was enlarged by drilled away ACP、PCP and cut the tentorium of cerebellum.3.Through the extended middle fossa approach we can expose the middle segment of BA, the exposure was limit and could be enlarged by cut the tentorium of cerebellum anteriorly and drilled away the labyrinth.4. Through the presigmoid approach we can expose the lower segment of BA, the exposure was enlarged by drilled away the labyrinth.5.The BA approaches were difficult, we should grasp the regular approaches by anantomy practice and combine multiple approaches to tackle with complex cases.6.Wingspan stent for treatment of basilar stenosis is safe and feasible in short-term. However, the technique should be improved and long-term efficacy needs further investigation.