Case 1: A 62-yr-old woman presented with dizziness and vomiting for 12 days and was transferred to our hospital. Neurological examination showed difficulty walking, but other exams were normal for cranial nerves, motor/sensory function, coordination, and reflexes. CT imaging showed a small hematoma in the right fourth ventricle, middle cerebellar peduncle and pontine tegmentum. Magnetic resonance imaging performed with T1-weighted, T2-weighted and SWAN sequences suggested a cavernous malformation. The preoperative diagnosis was a cavernous malformation in the right middle cerebellar peduncle and pontine tegmentum. After discussion with her family, suboccipital craniotomy was planned.
Case 2: A 54-yr-old woman presented with numbness in right side for one year. One year ago, she felt numbness in he right limb and CT scan shown a small hemorrhage in the brain stem. After conservative treatment, she was improved and discharged from hospital. But two weeks ago, she felt numbness in right side and came to hospital again, and CT scan shown a rebleeding in her brain stem. Then she was admission to our department and MRI suggested a cavernous malformation in her left pontine tegmentum. After consent of the patient and her family, suboccipital craniotomy with telovelar approach by the neuroendoscopy was prepared.
Surgical procedures were performed with the patient in the lateral prone position, the head fixed in a head-holder with slight flexion. A midline suboccipital craniotomy was performed to expose the craniovertebral junction, and the posterior arch of the atlas was preserved. Under neuroendoscopic view, a Y-shaped dural opening was made, and the inferior edge of the tonsils, uvula, PICA and obex was exposed (Figure 1,2). The tonsil and uvula were elevated and retracted by a thin transparent endoport, and then the tela choroidea, inferior medullary velum and floor of the fourth ventricle were visualized and protected. Looking forward to the upper ventricle, the hematoma was identified and removed under the neuroendoscope. With further access to the cerebellar peduncle and pontine tegmentum area, the residual hematoma in the cerebellar peduncle was cleared away, and a small cavernous malformation in the pontine tegmentum was identified and removed (Figure 1,2).
The symptoms of dizziness and vomiting disappeared immediately after the surgery in the first patient and the numbness was decreased in the second patient.Both of patients’ hospital course and recovery were uneventful. They recovered well and showed no new signs of brainstem or cerebellar dysfunction, and were discharged home 2 weeks postoperatively.
All procedures in human participants were performed in accordance with the ethical standards of the institutional and/or national research committee and the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Written informed consent for publication was obtained from the patient’s family members.