![]() ![]() CMs close to the brainstem have a poorer outcome and higher risk of bleeding and rebleeding. Some studies have noted out that early off-axis CM and CN have colloidal gaps that are prone to plane formation, which facilitates surgery. MRI is the preferred examination for the identification and follow-up of CMs located in the cisternal segment of the CN. On the basis of the abovementioned findings, early diagnosis is crucial for CMs of the CN, which can result in earlier complete resection of the lesion and anatomical and functional preservation of the nerve. Despite a decrease in the patient’s hearing postoperation, her facial nerve function was intact after surgery. During surgery in this case, we found that the lesion mainly involved the vestibular nerve. Furthermore, it is our belief that the factors affecting the recovery of CN function also include the existence of an arachnoid interface between the nidus and CN, a closer the adhesion between the nidus and CN, a higher the degree of infiltration, and a lower the integrity of the arachnoid interface, leading to greater damage to the nerve and a lower probability of CN functional recovery when completely resected. Lesion hemorrhage and reduced blood supply to the nerve during growth lead to nerve dysfunction before surgery. We agree that preservation of nerve function after surgery mainly depends on the lesion origin. Because these CMs may less likely be derived from CN VII but only compress or slightly adhere to the facial nerve. Comparatively, the functional recovery of the facial nerve reported in the literature seem to be better. It has been reported that hearing retention is difficult to achieve in patients with CMs located in the CPA, This difficulty may be related to the more fragile and less ischemic tolerance traits of the auditory nerve, and regional deposition of hemosiderin and severe adhesion after repeated bleeding. However, preservation of auditory and facial nerve(especially the former) function after surgery is still a difficult problem. Owing to the narrow space of the CPA and the complex anatomical structure surrounding it, it is challenging to completely remove the cranial nerve cisternal segment CM, however, this surgery can be achieved under the current conditions of microscopic technology and electrophysiological monitoring. Based on the intraoperative observation, the lesion in our case does not appear to be accompanied by a venous anomaly (Fig. ![]() To the best of our knowledge, ours is the second case reported to date. reported the first case of CM in the cisternal segment of the eighth cranial nerve near the brainstem in 1998, which was associated with venous aneurysm. 2).ĬMs of CNs are extremely rare, leading to their diagnosis and treatment being challenging. This cerebellopontine fissure vein did not appear to be the tortuous vein seen in the preoperative digital subtraction angiography (Fig. Although the veins of the cerebellopontine fissure adjacent to the lesion were thicker, there was a glial layer between them, and no vascular branches were connected. ![]() The bulk of the lesion appeared to be located on the vestibular nerve with relatively minor involvement of the cochlear nerve structures whilst sparing the facial nerve. The angioma was successfully resected en bloc, and the microvessels feeding it were cauterized with 3 w, which was a weak power of electrocoagulation for hemostasis, so as to ensure that no heat was transmitted to the facial nerve. The lesion was dark red and comprised a large number of tortuous small thin-walled vessels mixed with old bleeding, It was well-margined with dimensions of 1.0 × 0.8 × 0.5 cm and was buried in the proximal cisternal portion of the auditory nerve. The surgeon used the brain spatula reasonably and intermittently, combined with dynamic micro traction technology to explore and treat the lesion in the CPA area. After extensive discussions with the patient about various surgical options and risk benefits, microsurgery was performed to remove to the lesion, and the surgery used a left retrosigmoid approach, with the patient in the lateral position under neuromonitoring. ![]()
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