The Clinical Significance Of Protection Of Petrosal Vein In The Acoustic Neuroma's Microsurgery

Objective:To investigate the clinical significance of the protection of petrosal vein in the acoustic neuroma surgery.Methods:From January2009to July2011, a total of149acoustic neuroma microsurgical cases were observed. Detail characteristics of clinical data with the petrosal vein without retained cases were reviewed. The retrospective study compared the characteristics of clinical data of petrosal vein without retention group with retention group. Retrospective study of characteristics of clinical data of whom performed second posterior fossa decompression after acoustic neuroma microsurgery were conducted.Results:149patients with intact petrosal vein in141cases, the retained rate of94.6%.Petrosal vein failed to retain patients (hereinafter referred to as the former), the average age of43.5years, petrosal vein to retain patients (hereinafter referred to as the latter), mean age46years; four cases of the former men and women, the latter50cases of male, female84cases; the former course of the disease with an average of6.8years, the latter course of disease with an average of3.8years; the former tumor average diameter of46mm, the latter tumor size average of38.6mm; only one case of the former tumor cystic mainly,27cases of the latter tumors cystic mainly. Reexamination after the operation former see cerebelepontine angle(CPA) hematoma occurred (4/8), cerebellar edema (5/8), cerebellar hemorrhage (3/8),1patient underwent posterior fossa decompression. No patient with lateral ventricle drainage, postoperative hospital stay of14days; the latter found after the surgery CPA hematoma40cases, and cerebellar edema in56cases and cerebellar hemorrhage in12cases,6cases performed posterior fossa decompression, lateral ventricular drainage two cases, the average postoperative length of hospital stay was10.6days.The statistical analysis between the two groups there was no significant difference in the probability of occurrence of CPA hematoma and cerebellar edema. The statistical analysis show there was significant difference of the incidence of cerebellar hemorrhage between petrosal vein retention group and without retain group. Multivariate analysis show petrosal vein reservation was a protective factor for shorter hospital stay.Posterior fossa decompression in seven cases with an average age of47.6years,3males and4females, average disease duration of4.0years, an average of40.7mm maximum tumor size, no cystic tumor. After operation CPA hematoma occured (6/7), cerebellar edema (7/7), cerebellar hemorrhage (5/7). Six cases of patients with petrosal vein reserved. The mean postoperative hospital stay was14days. Conclusion:In acoustic neuroma surgery, the petrosal vein should be well protected under current microsurgical techniques. Protect the petrosal vein may reduce the risk of cerebellar hemorrhage. Also May shorten the postoperative hospital stay.Once the failure to retain the petrosal vein, the timely expansion of the sutured dura after surgery or even open the dura, to expand the bone window for decompression, if the cerebellum swelling significantly associated with contusion, removal of part of the lateral cerebellar for decompression may be considered, intensive observed after surgery, and actively prepared for second posterior fossa decompression.The postoperation decompression of posterior fossa in acoustic neuroma cases were mainly due to cerebellar hemorrhage, CPA hematoma and cerebellar edema. Proposed the indications of posterior cranial fossa decompression should be appropriate to widen, as the high pressure in posterior fossa could cause the urgent foramen magnum hernia lead to sudden respiratory arrest which may cause sudden death of patients. Precautionary measures to protect cerebellar draining veins and cerebellum tissue, and intraoperative complete hemostasis, also postoperative routine CT scan could discover abnormality timely.