In this study, the data of neurosurgery patients in our hospital from March 2020 to March 2022 were collected. The inclusion criteria were patients with treatment of brainstem and fourth ventricle lesions by the full neuroendoscopic in telovelar approach, including brainstem cavernous hemangioma, brainstem tumor, etc. The preoperative and postoperative imaging data, intraoperative neuroendoscopic video images and clinical manifestations were collected. A total of 5 patients with complete data were collected, including 1 male and 4 females, aged 3–67 years. The detailed clinical information is shown in Table 1.

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 were exposed (Figs. 1–5). 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 neuroendoscopy. 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 (Figs. 1, 2 and 3).

Resection a middle cerebellar peduncle and pontine tegmentum cavernous malformation by full neuroendoscopic telovelar approach. A CT imaging shown a small hematoma in the right fourth ventricle, middle cerebellar peduncle and pontine tegmentum. B MRI SWAN sequence suggested a cavernous malformation; C patient in the lateral prone position with the head fixed in a head-holder and slightly flexed; D a midline suboccipital craniotomy was performed, and the posterior arch of C1 was preserved; E under neuroendoscopic view, the inferior edge of the tonsils, uvula, PICA and obex was exposed. F The tela choroidea, inferior medullary velum and floor of the fourth ventricle were visualized and protected. G The hematoma in the fourth ventricle was exposed and removed. H The hematoma in the middle cerebellar peduncle was exposed and removed. I A small, cavernous malformation in the pontine tegmentum was identified and removed. J The cavity was checked after the operation. K Postoperative CT scan shown the hematoma was removed completely. L Histopathological examination revealed a cavernous malformation

Resection a pontine tegmentum cavernous malformation by full neuroendoscopic telovelar approach. A CT imaging shown a small hematoma in the left pontine tegmentum. B T2-MRI shown irregular and heterogeneous signals in pontine tegmentum; C MRI SWAN sequence suggested a cavernous malformation; D head fixed in a head-holder and slightly flexed; E the median aperture of the fourth ventricle was exposed. F The tela choroidea, inferior medullary velum was visualized and protected. G The floor of the fourth ventricle was exposed. H The upper fourth ventricle floor was exposed, and the median eminence yellowing. I A small, cavernous malformation in the pontine tegmentum was identified and removed. J The patient recovered well after the operation. K Postoperative CT scan shown the hematoma was removed completely. L Histopathological examination revealed a cavernous malformation

Resection a right pontine arm cavernous malformation by full neuroendoscopic telovelar approach. A CT imaging shown a small hematoma in the right pontine arm. B–D MRI showed a cavernous hemangioma with hemorrhage in the right pontine arm. E Head fixed in a head-holder and slightly flexed. F The lesion was seen under neuroendoscopy. G Resection of lesion under neuroendoscopy. H, I After lesion resection, neuroendoscopic exploration of the fourth ventricle showed the outlet of aqueduct of midbrain. J The complete lesion. K Postoperative CT scan shown the lesion was removed completely. L Histopathological examination revealed a cavernous malformation

The posterior median foramen of the fourth ventricle was explored under neuroendoscopy. It was found that the tumor had protruded from the posterior median foramen. The important structures of the latch of medulla oblongata and brain stem were protected, and the tumor was removed in blocks (Fig. 4). Explored the floor of the fourth ventricle under neuroendoscopy. It was found that the lesion was located at the back of the pons. Blocked the outlet of the midbrain aqueduct, separated and removed the lesion. The exploration showed that the cerebrospinal fluid circulation of the fourth ventricle and midbrain aqueduct was unobstructed (Fig. 5).

Total neuroendoscopic resection of brainstem medulloblastoma. A–C MRI showed space occupying lesions of brainstem. D Head fixed in a head-holder and slightly flexed. E The lesion was seen under neuroendoscopy. F Resection of lesion under neuroendoscopy. G The lesion was completely resected under neuroendoscopy. H Postoperative CT scan shown the lesion was removed completely. I Histopathological examination revealed a medulloblastoma

Total neuroendoscopic resection of astrocytoma of brainstem and fourth ventricle. A–C MRI showed space occupying lesions in the brain stem and the top of the fourth ventricle. D MRI showed supratentorial hydrocephalus. E Head fixed in a head-holder and slightly flexed. F The median aperture of the fourth ventricle was exposed. G The lesion was seen under neuroendoscopy. H Resection of lesion under neuroendoscopy. I Enlarged midbrain aqueduct outlet after hydrocephalus. J Exploration of the third ventricle via midbrain aqueduct using neuroendoscopy. K: Postoperative CT scan shown the lesion was removed completely. L Histopathological examination revealed a pilocytic astrocytoma. SM: stria medullaris; VII: facial colliculus; XII: hypoglossal triangle; X: vagal triangle; GT: gracile tubercle; MA: median aperture; MS: median sulcus; ME: median eminence; AM: aqueduct of midbrain; PICA: posterior inferior cerebellar artery

A 62-year-old woman presented with dizziness and vomiting for 12 days and was transferred to our hospital. Neurological examination showed difficulty walking, and other exams were normal for cranial nerves, motor/sensory function, coordination, and reflexes. CT imaging showed small hematoma in the right fourth ventricle, middle cerebellar peduncle, and pontine tegmentum. Magnetic resonance imaging (MRI) 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.

A 54-year-old woman presented with numbness in right limb for one year. One year ago, she felt numbness in the right limb and CT scan shown small hemorrhage in the brainstem. After conservative treatment, she was improved and discharged from local hospital. But two weeks ago, she felt numbness in right side and came to hospital again, and CT scan shown rebleeding in the brainstem. Then she was admission to our department and MRI suggested a cavernous malformation in the left pontine tegmentum. After consent of the patient and her family, suboccipital craniotomy with telovelar approach by the neuroendoscopy was prepared.

A 67-year-old woman with dizziness for 2 months. Brain MRI examination in the local hospital found a lesion on the right side of brainstem, so she was referred to our hospital. Brain MRI + SWI in our hospital showed cavernous hemangioma of the right pontine arm. Communicate the condition and operation plan with the patient and her family, and operate with the consent. The patient recovered well after operation, the symptoms of dizziness disappeared, and there were no obvious complications after discharge.

A 3-year-old boy with unstable walking for 3 days. Before admission, the child was unstable in walking, fell for many times, and his body tilted to the right. Brain CT of the local hospital showed a lesion on the brainstem. After being transferred to our hospital, the child had rapid heart rate, disturbance of consciousness, vomiting and aspiration, airway obstruction, endotracheal intubation, and other rescue treatment. The emergency brain MRI + enhanced examination showed that the medulloblastoma on the brainstem were possible. The patient was in critical condition. After communicating with the family members and obtaining the consent of the family members, the emergency craniotomy was performed. After the operation, the child was complicated with severe pneumonia and transferred to pediatric ICU for further treatment. Pathological examination showed medulloblastoma. The child’s vital signs were unstable, and the prognosis was very poor. So the family chose to give up treatment and leave the hospital automatically.

A 32-year-old woman with dizziness and nausea for 3 months. The patient went to the local hospital and underwent brain MRI, which showed that the obstructive hydrocephalus. After referral to our hospital, brain MRI + enhanced examination showed that the lower end of midbrain aqueduct occupied space and the supratentorial hydrocephalus was formed. Communicate the condition and operation plan with patient and her families and operate with the consent. Pathological examination showed pilocytic astrocytoma. The patient recovered well after operation, the symptoms of dizziness and nausea disappeared, there were no obvious complications after discharge, and the hydrocephalus improved after follow-up.