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Basilar invagination is a congenital or acquired craniovertebral junction abnormality where the tip of the odontoid process projects through the foramen magnum which can cause severe symptomatic compression of the brainstem and spinal cord. If left untreated, patients can develop progressive quadriparesis. Traditionally, basilar invagination can be treated with cervical traction and posterior stabilization. However, in irreducible cases, anterior decompression via a transoral or endonasal approach may be necessary. In this operative video, we demonstrate an endoscopic endonasal transclival approach for odontoidectomy to successfully treat a 37-year-old female with severe basilar invagination causing symptomatic compression on the cervicomedullary junction resulting in unsteady gait and motor weakness. The patient had Klippel–Feil syndrome where the C1 arch was assimilated to the foramen magnum and transclival drilling was needed to adequately access the odontoid process for removal. A second-stage posterior occipitocervical stabilization and fusion was performed the following day. Immediate postoperative imaging showed excellent decompression of the cervicomedullary junction. Postoperatively, the patient had significant improvement in gait and motor strength in all extremities, and was ambulating independently without assistance at 1 year after surgery. The endoscopic endonasal transclival odontoidectomy is a useful strategy to treat severe irreducible basilar invagination causing symptomatic neural compression. The surgical technique and nuances are described in a step-by-step fashion in this illustrative operative video.The link to the video can be found at: https://youtu.be/HL4K7KqJEJM.

We report a case of craniocervical junction dural arteriovenous fistula (dAVF) presented with myelopathy and normal pressure hydrocephalus, and was treated with hybrid approach of embolization and surgical disconnection. A 68-year-old gentleman presented with 1 year history of unsteady gait and sphincter disturbance. Magnetic resonance imaging (MRI) showed abnormally enlarged and tortuous vessels over right cerebellomedullary cistern. Digital subtraction angiogram (DSA) showed Cognard's type-V dAVF at craniocervical junction. Catheter embolization was performed via external carotid artery and finally surgical disconnection was done with far lateral approach (Fig. 1). Postoperative DSA showed no more arteriovenous shunting (Fig. 2). Clinically the patient improved after a course of rehabilitation. Dural AVF at craniocervical junction is rare and its clinical presentation can be highly variable from subarachnoid hemorrhage to brainstem dysfunction. Identification of the exact fistula site is essential in surgical planning. Surgery is effective and safe to achieve complete obliteration and good clinical outcome.1 2 3 4 5 6 The link to the video can be found at: https://youtu.be/xI48stSlWpY.

We present a case of a large jugular tubercle meningioma that was removed through a midline suboccipital subtonsillar approach in semisitting position. The patient is a 49-year-old woman with chronic, medication-resistant cephalgias but devoid of any subjective focal neurological deficit. On magnetic resonance imaging (MRI), an extra-axial lesion, originating from the left jugular tubercle was discovered. There was significant obliteration of the peripontine cisternal space, and compression of the adjacent pontomedullary junction; the lesion also extended into the left jugular foramen.On physical exam, an absent gag reflex was noted on the left, as well as a moderate deviation of the uvula to the contralateral side (partial Vernet's syndrome).A gross-total resection was achieved, histopathology confirmed a World Health Organization (WHO) grade I angiomatous meningioma with a low-proliferation index. The patient was discharged home 4 days after surgery with intact function of the lower cranial nerves (CN) following immediate and complete resolution of the preexisting partial CNs IX and X deficits. At 2-year follow-up, there was no indication of intradural residual or recurrence.In summary, the midline suboccipital subtonsillar approach is a simple and effective tool with limited morbidity in the armamentarium for the microsurgical management of pathologies residing in the posterior cranial fossa or the craniocervical junction.Major limitations exist for lesions extending above the internal acoustic canal or those of fibrous consistence featuring widespread adhesion to the ventral brainstem or vascular encasement. Provided the necessary anesthesiological precautions and intraoperative procedures the semisitting position is safe and effective.The link to the video can be found at: https://youtu.be/bbVXagwhDCo.

Objectives Safe maximal resection is the basic principle of cranial base surgery and the grade of resection is an important factor influencing the prognostic outcome. This operative video highlights the surgical principles and technical nuances in the microsurgical resection of foramen magnum meningioma (FMM). Case Description The surgery was performed in a 45-year-old lady who presented with hoarseness of voice and spastic quadriparesis (grade 4/5). On imaging, FMM with mass effect on brainstem and spinal cord was identified. The tumor was gross totally resected through modified far lateral approach with minimal occipital condyle drilling. This video demonstrates the surgical techniques of tumor resection including early devascularization, operating in the arachnoid plane to dissect the neurovascular structures, piecemeal decompression, sharp dissection to separate tumor from lower cranial nerves (LCN), identifying the brainstem veins, and resecting the lesion from tumor–brainstem interface. Postoperatively, she had significant neurological improvement and the magnetic resonance imaging revealed excellent radiological outcome (Figs. 1 and 2). Conclusion The surgery of FMM is challenging due to the deep surgical corridor, critical location, close proximity with various neurovascular structures, firm consistency, and high vascularity of the tumor. The modified far lateral approach by preserving the occipital condyle may prevent the postoperative incidence of craniovertebral junction instability. The key operative principles to achieve the best surgical outcome include careful dissection along the arachnoid plane, gentle handling of cranial nerves, veins, and perforator vessels, avoidance of traction on brainstem and spinal cord, intraoperative neurophysiological monitoring, proper hemostasis, and meticulous dural closure.The link to the video can be found at: https://youtu.be/1qvAeUmNIUw.

Glomus tumors, also called paragangliomas, are challenging lesions, demanding accurate knowledge of complex anatomy and pertinent approaches. We present the case of a 39-year-old male presenting with headache, vertigo, tinnitus, hearing loss, and hoarseness. Neurological assessment showed facial paralysis House–Brackmann IV and lower cranial nerves deficits. Preoperative magnetic resonance imaging (MRI) demonstrated two large lesions, suggestive of a glomus jugulare, and carotid body paragangliomas. Considering worsening of the symptoms and the important mass effect of both lesions over the neurovascular structures, microsurgical excision was offered, after preoperative tumor embolization. We preferred to approach both lesions in the same operation, starting by the cervical tumor. Initially there was not an easily identifiable dissection plane between the tumor and the carotid artery, but it was achieved after performing a subadventitial dissection, being possible to resect the entire lesion. The jugular foramen lesion was approached through a postauricular transtemporal approach, skeletonizing the sigmoid sinus, jugular bulb, and facial nerve, following a complete mastoidectomy. The tumor, extending to the intradural compartment, middle ear, internal auditory canal, petrous internal carotid artery, and internal jugular vein was completely removed. Postoperative MRI demonstrated complete resection of both lesions, and pathology confirmed to be paragangliomas. In the immediate postoperative period, the facial paralysis evolved to House–Brackmann grade VI, improving to grade III during follow-up. The patient underwent a vocal cord medialization in order to improve voice quality and swallowing. These are challenging lesions and extensive laboratory training is mandatory to be familiarized with the regional anatomy and its various surgical approaches.The link to the video can be found at: https://youtu.be/gA_ckwFq_9c.

Objectives We present a challenging case of a 61-year-old male patient with a double meningioma. The first one was located on the right side of foramen magnum and the second one was located on left anterolateral side of C1–C2. Background Patient referred at our institution for a progressive spastic paraparesis from approximately 1 year with a recent onset of numbness in right hand. Neuroradiological imaging showed an extra-axial enhancing tumor with a dural tail on the right border of foramen magnum and another contralateral extra-axial enhancing lesion at C1–C2 level (Fig. 1). Results We have chosen a park bench position. Neurophysiological monitoring was used during both positioning and surgery. A linear skin incision in the occipital region extended to C7 was performed and a suboccipital craniotomy with the laminectomy of C1–C3 was performed (Fig. 2). Videofluroangiography was performed to the best visualization of the vertebral artery position during microsurgical dissection and exposure of craniovertebral junction region. An Y-shape dural opening was executed and two meningiomas was resected with the classical four D steps (devascularize, detach, debulking, and dissect). All anatomical structures were respected and there were no changes at neuromonitoring. Patient was discharged after 10 days in good neurological condition. Conclusion a single approach for multiple meningiomas of the craniovertebral junction and upper cervical spine region is feasible and effective. Videofluoroangiography as a way to achieve better visualization and control of the vertebral artery, and neurophysiological monitoring are crucial tools to reduce the morbidity of this surgical challenge.The link to the video can be found at: https://youtu.be/4w9HCfQZkgg.

Surgical access to the ventral foramen magnum remains a technical challenge. With large lesions in this region compressing the brainstem and distorting the regional neurovascular relationships, formulating a surgical plan and its appropriate execution have crucial importance in achieving favorable outcomes. While the endoscopic endonasal approaches have gained increasing attention to access the clivus and the ventral brainstem, foramen magnum meningiomas are still preferred to be removed via an approach that obviates a trajectory through the nasopharyngeal mucosa. Therefore, the far lateral approach remains one of the most practical approaches for these challenging lesions. This operative video demonstrates the use of the far lateral transcondylar transtubercular approach to remove a large meningioma in the ventral foramen magnum in a 63-year-old male with progressive cervical myelopathy, presenting as spastic quadriparesis without any cranial nerve abnormality. Using a right-sided far lateral transcondylar transtubercular approach, the meningioma was exposed within the cerebellomedullary gutter engulfing the vertebral artery and distorting the course of the adjacent cranial nerves. Using the different corridors identified between the vertebral artery, spinal accessory, vagus, and hypoglossal nerves, multiple angles of attacks to the tumor were established and utilized to resect the lesion. A gross total resection was achieved and the patient was neurologically intact without any neurological deficits. This video demonstrates the importance of understanding the intricacies of neurovascular anatomy of the cervicomedullary region (i.e., the various triangles formed between these structures), and the effective use of these corridors to safely and efficiently remove a challenging ventral foramen magnum meningioma with neurovascular involvement, while preserving cranial nerve function. The surgical technique and nuances are described in a step-by-step fashion in this illustrative operative video.The link to the video can be found at: https://youtu.be/s1dFhuaRSt8.

Objectives To demonstrate the feasibility of the retrosigmoid craniotomy for surgical management of vascular lesions located in the cerebellopontine angle (CPA). Method A previously healthy 2-year-old boy presented a sudden episode of torticollis to the left while sleeping. This episode was selflimited but it occurred two more times in a 6-day span. Torticollis worsened in the upright position, caused unsteady gait and refusal to walk from the child. The preoperative magnetic resonance imaging (MRI) showed the presence of a round, heterogenous vascular lesion in the left CPA. The lesion clearly enhanced after contrast administration. The preoperative angiography demonstrated the absence of left anterior inferior cerebellar artery anterior inferior cerebellar artery (AICA), being the left superior cerebellar artery (SCA) the supplier of the left lateral cerebellum. A blurred blush on the distal left SCA was compatible with a fusiform aneurysm. A standard retrosigmoid approach was planned for trapping and removal of the aneurysm. Results Through a left retrosigmoid craniotomy the aneurysm was approached, along with the different neurovascular structures of the CPA. The aneurysm leaned on the VII, VIII nerves complex and the superior petrosal vein, while tightly attached to the lateral cerebellum. Both proximal and distal SCA segments to the aneurysm were dissected, clipped, and divided for a complete trapping. Finally, the aneurysm was completely detached and removed in a whole piece. The patient fully recovered after surgery with no relapse of his symptoms. Conclusion The retrosigmoid craniotomy is a versatile approach that permits wide exposure of all CPA structures and adequate removal of distal aneurysms located in those cerebellar arteries supplying the lateral cerebellum.The link to the video can be found at: https://youtu.be/oEVfy4goFYM.

Craniovertebral junction chordomas can represent a surgical challenge, especially when intradural extension and contact with neurovascular structures is involved. To date, there is still controversy on the choice of optimal surgical corridor for such lesions, with endoscopic endonasal, far lateral and anterolateral corridors being those most commonly used. In this operative video, we present a case of craniovertebral junction chordoma with significant bone destruction and intradural extension (Fig. 1). The tumor was safely removed using an anterolateral approach with transposition of the vertebral artery to gain access to the lateral craniovertebral junction. The endoscope is demonstrated to help with intradural tumor removal, providing a wide angle of view through a relatively narrow dural opening (Fig. 2). In this video, nuances of the anterolateral approach, chordoma removal strategies and closure technique are presented in detail. A gross total resection was achieved, and the postoperative course was uneventful. In summary, the anterolateral approach with endoscopic assistance can offer a safe and effective corridor for the surgical management of craniovertebral junction chordomas.The link to the video can be found at: https://youtu.be/pC0YxKgNoMY.

Objective Foramen magnum meningiomas present a formidable challenge to resection due to frequent involvement of the lower cranial nerves and vertebrobasilar circulation. The video shows the use of a far lateral craniotomy to resect a foramen magnum meningioma. Design, Setting, and Participant A 49-year-old woman presented with neck pain and was found to have a large foramen magnum meningioma (Fig. 1A, B). Drilling of the posterior occipital condyle was required to gain access to the lateral aspect of the brain stem. The amount of occipital condyle resection varies by patient and pathology. Outcome/Result Maximal total resection of the tumor was achieved (Fig. 1B, C), and the patient was discharged on postoperative day 4 with no neurologic deficits. The technique for tumor microdissection (Fig. 2) is shown in the video. Conclusion Given the close proximity of foramen magnum meningiomas to vital structures at the craniocervical junction, surgical resection with careful microdissection and preservation of the overlying dura to prevent postoperative pseudomeningocele is necessary to successfully manage this pathology in those patients who are surgical candidates.The link to the video can be found at: https://youtu.be/Mds9N1x2zE0.

Surgical removal of glomus jugulare tumors is challenging owing to the complex anatomy of the temporal bone and craniocervical region, aggressive tumor invasion into the nearby structures, and their hypervascularity. However, recent advances in skull base techniques, intraoperative neuromonitoring, and radiological interventions have enabled their relatively safe resection, while giving priority to functional preservation. This video demonstrates a case of a glomus jugulare tumor treated by the extradural transjugular transsigmoid approach with high-cervical exposure and tympamoplasty, after preoperative embolization. A 47-year-old woman presented with progressive hearing disturbance, pulsatile tinnitus, and hemifacial spasm. Neuroimaging displayed a hypervascular tumor occupying the temporal bone, extending to the cervical region through the jugular foramen, and to the external auditory canal. Preoperative feeder occlusion was successfully performed without any additional symptoms, while carefully evaluating the provocative test. Near-total resection of the tumor was achieved through the transjugular transsigmoid approach with high-cervical exposure under detailed neuromonitoring, including continuous facial nerve monitoring and auditory brainstem response. In this patient, in whom the tumor did not invade intradurally and the sigmoid sinus was already occluded preoperatively, the sinus was managed only by coagulation, to avoid unnecessary dural opening and the risk of cerebrospinal fluid leakage. Anterior facial nerve rerouting was not required since the tumor removal was accomplished through the corridor above and below the fallopian bridge. The patient had no new neurological deficits, and her pulsatile tinnitus and hemifacial spasm disappeared after the surgery. Her hearing disturbance improved postoperatively.The link to the video can be found at: https://youtu.be/gqf3dxHlv_0.

Objective This study was aimed to achieve gross-total removal of a chordoma of the craniocervical junction via an endonasal approach ( Fig. 1 ). Fig. 1 Pre- and postoperative images of the craniocervical junction chordoma. ( A ) It shows a preoperative sagittal T2-weighted MRI image. ( B ) It shows a preoperative axial T2-weighted MRI image. Note that a T2-hyperintense lesion is located in the lower clivus and the odontoid. ( C ) It shows the postoperative sagittal T1-weighted gadolinium enhanced MRI image. ( D ) shows a postoperative axial T2-weighted MRI image. These images show the fat graft used for closure, but no evident tumor remnant. MRI, magnetic resonance imaging Design The present study is a case report. Setting The study was conducted at neurosurgical clinic of university hospital. Participant A 40-year-old male, with normal neurologic exam and no prior medical history, presented with a 2-year history of cervicalgia. On preoperative imaging, a midline lesion, with image characteristics of chordoma, was seen in the lower clivus and odontoid. It had limited lateral extension. Main Outcome Measures This study measures postoperative neurological deficits and postoperative tumor volume on magnetic resonance imaging (MRI). Results A binostril approach to the upper nasopharynx was performed using endoscope at 30- and 45-degree angles. Subsequently, a heart-shaped mucosal flap was made and the clivus was drilled to expose the lesion ( Fig. 2 ). After initial debulking, the ring of C1 was slightly drilled to reach the tumor in and around the odontoid. Postoperative MRI showed that a gross-total resection was achieved. The patient had no neurologic deficits postoperatively. Pathologic examination revealed a chordoma of the classical type. Fig. 2 Illustration of the endoscopic endonasal surgical technique. ( A ) It shows the surgical route (blue arrow), and location of the heart-shaped mucosal flap that was made in the upper nasopharynx (blue crescent). This figure highlights that angled endoscopes are needed to visualize the relevant operative field (yellow translucent triangle). ( B ) shows the axial view, ( C ) shows an intraoperative endoscopic view of the incision performed to achieve a heart-shaped mucosal flap, as was utilized during this case, and ( D ) shows the coronal view. ( B and D ) They show the results of postoperative image analysis, during which we segmented the drill cavity (in blue) and projected it on the preoperative CT scan of the patient. Note that besides the inferior clivus, the superior part of the ring of C1 was also drilled slightly to reach the tumor in the odontoid. CT, computed tomography. Conclusion An endoscopic endonasal approach, utilizing the heart-shaped flap and angled endoscopes and instruments, can be considered for resection of select cases of craniocervical junction chordoma with limited lateral expansion. The link to the video can be found at: https://youtu.be/rwVoZJRBIEo .

Objectives Vestibular schwannomas (VS) extending into the internal auditory canal (IAC) are currently considered as an unfavorable condition for hearing preservation surgery (HPS) via retrosigmoid (RS) approach due to the poor direct visualization of the facial and cochlear nerves course through the IAC and the fundus during microsurgery. Design The operative steps are described in a surgical instructional video. Setting The surgery took place at a tertiary-care center. Participants Patient is a 45-year-old man who was incidentally diagnosed with an extrameatal VS extending for 9 mm into the left cerebellopontine angle (CPA). Hearing function at diagnoses was excellent, with pure tone average (PTA) = 15 dB and speech discrimination score (SDS) = 100% (class A according to the Tokyo classification) and minimal impairments on auditory brainstem response (ABR). Given these preoperative features in small VS, hearing was the main function to look into in the treatment planning. Initial observation or HPS were proposed. Results The patient underwent surgical excision for HPS via RS approach combined with retrolabyrinthine meatotomy (RLM). RLM enables the complete exposure of the IAC to the fundus, after drilling the bony surface of the posterior IAC wall, under guidance of the anatomical landmarks, namely, the endolymphatic duct, the blue lines of the posterior, and superior semicircular canals, and common crus. Nor intra-, neither postoperative complications occurred. Histologic examination confirmed the diagnosis of VS. A 3-month short-term follow-up revealed a class B hearing function with PTA = 30 dB, SDS = 100%, and normal facial nerve status. Conclusions RLM via RS approach proved to be effective for HPS, enabling the full course of the facial and cochlear nerves through the IAC to be directly exposed.The link to the video can be found at: https://youtu.be/KC1S4pxpLCk.

A 45-year-old male patient with reduced hearing in the right ear was diagnosed with a medium-sized (T3a) acoustic neuroma. The operation was performed through an individually tailored retrosigmoid mini-craniotomy. Endoscope-assisted microsurgical technique was applied to early detect the location of the facial and cochlear nerves as well as to look around the hidden corners during the surgery. The entire operation was performed without using brain retractors. The moderate intrameatal extension of the tumor and the use of angled endoscopes allowed to avoid the drilling of the internal auditory meatus. The lesion could be completely removed and the patient showed a satisfactory hearing recovery in the follow-up examinations 3 months after the surgery.The link to the video can be found at: https://youtu.be/dAYLakih924.

Meningiomas of the cerebellopontine angle (CPA) are the second most frequent lesions related to this region (around 10–15%),1 being the vestibular schwannomas the first (around 85%). This lesions arise from the dura of the petrosal surface of the temporal bone, lateral to the trigeminal nerve (Fig. 1). Variable attachment sites and directions of growth make different clinical presentations and operative challenges. This pathologies can be classified accordingly to they're extension related to the internal acoustic meatus in: postmeatal, premeatal, and large meningiomas with pre- and postmeatal extension (Fig. 2). We present an operative video performed by the senior author (L.A.B.B.). A 64-year-old woman with 3 months of complaint of left facial pain on the V2 territory of the trigeminal nerve and diplopia secondary to VI nerve paresis. Magnetic resonance imaging (MRI) scans demonstrated a large homogeneous enhancing lesion at the left CPA, extending pre- and postmeatal and from the tentorium cerebeli to the jugular foramen region, highly suggestive of CPA meningioma. Surgery was offered to the patient as a first option. In our point of view, neurophysiological monitoring with somatosensory and motor evoked potentials is mandatory while dealing with such large tumors around the CPA. The surgery was performed after a standard retrosigmoid craniotomy, with careful dissection and debulking while devascularizing the tumor from its petrosal attachment. Near-total resection was achieved and the patient had a remarkable postoperative outcome with improvement of the diplopia and facial pain with preservation of VII and VIII nerves function. The pathology demonstrated a grade 1 meningioma.The link to the video can be found at: https://youtu.be/UVVyEhq8Fu0.

Objectives This study aimed to demonstrate resection of a craniovertebral junction (CVJ) meningioma via the posterolateral approach. Design The study is designed with a two-dimensional operative video. Setting This study is conducted at department of neurosurgery in a university hospital. Participants A 50-year-old woman who presented with lower cranial nerve findings due to a left-sided lower clival meningioma (Fig. 1). Main Outcome Measures Microsurgical resection of the meningioma and preservation of the neurovascular structures. Results The patient was placed in park-bench position and a left-sided retrosigmoid suboccipital craniotomy, followed by C1 hemilaminectomy and unroofing the lip of the foramen magnum, was performed. The dural incision extended from the suboccipital region down to the posterior arch of C2 (Fig. 2). The arachnoid overlying the tumor was incised, revealing the course of the cranial nerve (CN) XI on the dorsolateral aspect of the tumor. The left vertebral artery (VA) was encased by the tumor which was originating from the dura below the jugular foramen. The mass was resected in a piecemeal fashion eventually. At the end of the procedure, all relevant cranial nerves and adjacent vascular structures were intact. Postoperative magnetic resonance imaging (MRI) confirmed total resection and the patient was discharged home on postoperative day 3 safely. Conclusions Microsurgical resection of the lesions of the CVJ are challenging as this transition zone between the cranium and upper cervical spine has a complex anatomy. Since adequate exposure of the extradural and intradural segments of the VA can be obtained by the posterolateral approach, this approach can be preferred in cases with tumors anterior to the VA or when the artery is encased by the tumor.The link to the video can be found at: https://youtu.be/d3u5Qrc-zlM.

Objective The endoscopic endonasal odontoidectomy (EEO) is emerging as a feasible surgical alternative to conventional microscopic transoral approach. In this article, we show EEO in the basilar invagination (BI) and describe in detail the technical aspects, advantages, and disadvantages of this approach (Fig. 1). Methods We describe EEO using audiovisual material from the neurosurgical department of Hospital Universitari i Politècnic La Fe Valencia database. Results We present the case of a 61-year-old male patient with BI. Initially, we performed suboccipital decompression and occipitocervical fusion. Subsequently, after a no significant neurological improvement and persistent anterior compression, EEO was performed. The postoperative evolution was uneventful and the preoperative neurological deficits were recovered rapidly after surgery Discussion EEO technique enables complete odontoid resection, preventing invasion of aggressive oral bacterial flora, and it is not limited by the mouth opening. As well, it avoids manipulation of the soft palate, therefore evades the risk of velopalatal insufficiency, facilitates immediate oral tolerance, and early extubation. The rostral position of C1–C2 complex in BI could suppose a great advantage in favor the endonasal approaches. Mucoperichondrial vascularized flaps could be obtained to avoid a postoperative cerebrospinal fluid (CSF) leak and facilitate the reepithelization process of the surgical bed. Conclusion EEO may provide a significant anatomic and technical advantage over the trans-oral approach.The link to the video can be found at: https://youtu.be/Td6MDcjCNKk.

Objectives This study was to demonstrate surgical technique for an anterolateral foramen magnum meningioma. Design Present study is presented through an operative video. Setting This study is conducted at the Department of Neurosurgery, Tîrgu Mureș, Romania. Participants A 62-year-old female is the participant who was diagnosed with a foramen magnum meningioma. Main Outcome Measures Complete surgical resection of the tumor with no postoperative deficits or complications. Results A 62 years-old female was admitted for left hemilingual atrophia, dysphonia, right hemiparesis grade 2 of 5, right hemihypesthesia, and cervical pain. The magnetic resonance imaging (MRI) showed a right foramen magnum meningioma, sized approximately 2 cm in all planes (Fig. 1). This was classified with the Bernard system as an intradural foramen magnum meningioma with anterolateral insertion to the dura mater and below the vertebral artery. A suboccipital, retrocondylar, and c1 right hemilaminectomy approach was performed. Using microsurgical tumoral decompression techniques, ultrasonic aspiration, and following the natural cleavage planes, complete tumor removal was achieved (Fig. 2). The patient presented an uneventful postoperative course with no postoperative new neurological deficits and was discharged at home 7 days following surgery. Control MRI at 6 months (Fig. 1) and 2 years showed no tumor residue or recurrence. Neurologic status at 6 months was excellent, showing complete remission of symptoms. Conclusion Retrocondylar suboccipital approach is a safe and feasible option for anterolateral foramen magnum meningiomas provided that natural corridors and dynamic retraction are used.The link to the video can be found at: https://youtu.be/jpxMcjCpN6E.

Objectives This study aimed to demonstrate the technique of handling the anomalous vertebral artery in congenital atlantoaxial instability. The vertebral artery course can be variable in congenital atlantoaxial instability, especially if there is assimilation of atlas. The surgical technique to stabilize the atlantoaxial joint should ensure the patency and safety of the vertebral artery and prevents devastating stroke. Computed tomography (CT) angiography of the vertebral artery is mandatory in planning the surgical strategies. The vertebral artery can be injured during dissection of soft tissues between atlas and axis and can be compromised during distraction and instrumentation. The vertebral artery needs to be mobilized based on the tortuosity in the course during instrumentation and prevents compression of the artery against bony structures or screw heads. The vertebral artery has to be identified earlier in the course of dissection and should protect it. It is also imperative to choose the surgical approach that can be performed under vision using operative microscope rather than adapting blind procedures like transarticular screw. Here, in our present case, we demonstrate the technique of mobilizing the vertebral artery which was coursing medially preventing the access for the instrumentation and perform stabilization of atlantoaxial joint using Goel–Harms technique, and prevent its compression after placement of screw by deroofing the bony ridges of axis (Figs. 1 and 2). We also emphasize the various technical nuances during the stabilization with distraction of joint space of atlas and axis.The link to the video can be found at: https://youtu.be/pgURpF_jACc.

Objective This study aimed to demonstrate the nuances in preoperative management, surgical technique, and reconstruction for an endoscopic endonasal odontoidectomy. Design Assembly of an operative video demonstrating technique for endoscopic endonasal odontoidectomy. Setting this study is a comprehensive skull base team at a tertiary care center. Participant The patient is a 53-year-old male, with basilar invagination and myelopathy, who underwent cervical fusion, 6 years back, without ventral decompression at an outside hospital. He presented to our clinic with persistent myelopathy and generalized weakness, thus an endoscopic endonasal odontoidectomy for brainstem decompression was recommended. Main Outcome Measures Preoperative computed tomography (CT) angiography and intraoperative CT navigation demonstrated normal carotid artery anatomic localization. An inverted U-shaped mucosal flap was reflected inferiorly and preserved. The C1 arch was identified and resected with a high speed drill. The resultant diseased soft tissue arising from retropulsion of the odontoid process was then removed and the odontoid process identified. This bone was removed centrally until a thin cap remained. After removal of the cap, the underlying ligamentous tissue was removed until dural pulsations were appreciated and brainstem decompression achieved. Hemostasis was attained and the mucosal flap mobilized into position. Results Postoperative CT imaging demonstrated resolution of basilar invagination and brainstem decompression (Fig. 1). The patient improved both in arm dexterity and ambulation after surgery and the reconstruction demonstrated appropriate healing on nasal endoscopy 2 months postoperatively. Conclusions This operative video demonstrates nuances in endoscopic endonasal odontoidectomy. This case also demonstrates that ventral decompression after long-term cervical fusion can improve myelopathy and that fusion in the setting of bony ventral compression, rather than rheumatoid panus, may not reduce over time with fusion only.The link to the video can be found at: https://youtu.be/370FFuBA89Y.

Objectives Dural arteriovenous fistulas (DAVFs) at the cervicomedullary junction are uncommon and often accompanied by subarachnoid hemorrhage (SAH). We aim to illustrate in detail the microsurgical procedure for treating a DAVF located at the cervicomedullary junction. Design We present a two-dimensional operative video that includes clinical history, preoperative imaging, surgical strategy, still images with labels, clinical course, and postoperative imaging. Setting The microsurgery was performed at an academic medical center. Participant The patient is a 55-year-old female who presented with SAH, acute onset headache, nausea, and vomiting. Angiography demonstrated right vertebral artery vasospasm and a persistent arteriovenous shunt at the cervicomedullary junction supplied by small perforating arteries of the right vertebrobasilar junction (Fig. 1). Main Outcome Measures The patient was placed in the park-bench position with the head turned to the contralateral side. A hockey stick incision was made, followed by a right-side far-lateral transcondylar approach. Indocynanine green videoangiography was performed to help identify the areas of arteriovenous shunting. Multiple clips were placed to interrupt vessels that corresponded to arterial feeders at the level of the C1 and C2 nerve root sleeves (Fig. 2). The dura was closed in a water tight fashion and the posterior fossa was reconstructed with a titanium mesh. Results Postoperative imaging showed no evidence of continued arteriovenous shunting. The patient was discharged in good clinical condition with an uneventful postoperative course. Conclusion A deep understanding of the microsurgical vascular anatomy is necessary for successful occlusion of a cervicomedullary DAVF.The link to the video can be found at: https://youtu.be/-LfOcNB05BY.

Surgical removal of large jugular foramen schwannomas with intra- and extracranial extension is challenging. The treatment goal is a gross total resection of the tumor without causing surgical complications, including facial nerve paresis, hearing disturbance, dysphagia, hoarseness, and cerebrospinal fluid (CSF) leakage, in addition to the brain stem injury.We present a surgical video in a patient with a dumbbell-shaped glossopharyngeal schwannoma. The combination of posterior fossa craniotomy, mastoidectomy, and unroofing of the jugular foramen with high cervical exposure was selected. Although transposition of the mastoid segment of the facial nerve provides an excellent surgical corridor, it may affect normal facial nerve function. Sufficient drilling of the infralabyrinthine, retrofacial area of the mastoid without facial nerve transposition is important for the safe gross total removal of the tumor. Subcapsular removal behind the jugular vein is also important for preservation of the lower cranial nerve functions.The patient underwent a gross total removal of the tumor (Figs. 1 and 2). Facial nerve function was preserved and hearing disturbance improved. Although dysphagia and hoarseness complicated postoperatively, he became able to take foods orally 16 days after the surgery.In summary, successful removal of a large dumbbell-shaped jugular foramen tumor can be completed via infralabyrinthine, retrofacial, and transjugular approach without facial nerve transposition.The link to the video can be found at: https://youtu.be/U4CwOW78id4.

Glomus vagale tumor is a paraganglioma of the vagus nerve. It is a rare type of benign tumor that occupies the head and neck and skull base regions. Patients often present with lower cranial nerve dysfunctions such as difficulty swallowing, tongue weakness, and hoarseness. Surgical treatment can be complex and difficult due to its high vascularity, frequent involvement of lower cranial nerves, and surrounding critical vascular structures. In this operative video, we demonstrate an extended anterolateral infralabyrinthine transjugular approach for microsurgical resection of a giant glomus vagale tumor in a 53-year-old male who presented with an enlarging neck mass, difficulty swallowing, right tongue weakness, and hoarseness. Imaging revealed a giant glomus vagale tumor in the right parapharyngeal space extending into the jugular foramen with occlusion of the internal jugular vein. After preoperative embolization, the patient underwent a near-total resection of the tumor with a small microscopic residual at the pars nervosa. In summary, the extended anterolateral infralabyrinthine transjugular approach is a useful strategy for removal of giant glomus vagale tumors extending into the skull base. The surgical technique and nuances are described in a step-by-step fashion in this illustrative operative video.The link to the video can be found at: https://youtu.be/L0EosQK95LE.

Background Odontoidectomy may represent the treatment of choice for symptomatic ventral craniovertebral junction stenosis in selected cases. An endoscopic transnasal approach has been proposed as an alternative to a classic transoral approach. Method We report a case of a patient with a craniovertebral junction stenosis due to the ossification of the posterior ligament. The clinical and radiological records of the patient and a step-by-step description of the surgical technique are presented (Fig. 1). Conclusion Endoscopic transnasal odontoidectomy provides a direct access to the dens and adjacent structures of the anterior upper cervical spine with a less invasive burden on the oropharingeal structures.The link to the video can be found at: https://youtu.be/Ofrk1sFTV9I.

Background The far-lateral approach is an effective skull base technique that provides access to the lower clivus and premedullary area. This approach is also useful for maximal visualization and resection of large posterior fossa tumors with extensive medial extension, especially when aggressive resection is ideal for a malignant tumor in a young patient, or it is technically challenging because of tumor calcification. We demonstrate a microsurgical operative video to describe technical pearls in this difficult situation. Case Presentation A 45-year-old man with history of “hoarseness” for up to two decades was presented with imbalance and mild dysphagia over 3 years. Imaging demonstrated a 55-mm left cerebellopontine angle (CPA) tumor extending medially across the midline with severe calcification (Figs. 1 and 2). His neurological examination revealed left facial numbness, complete left facial weakness, left deafness, complete left vocal paralysis, as well as severe left hemibody ataxia. The tumor was resected via a left suboccipital craniotomy with far lateral approach including drilling to the occipital condyle and C1 laminectomy. Initial manipulation of the inferior pole of the tumor resulted in asystole which was managed successfully with glycol pyrolate. Pathology demonstrated IDH-1 wild type, MGMT-methylated glioblastoma. The patient subsequently underwent adjuvant chemoradiation. Conclusion The far-lateral approach is an effective approach for maximal safe resection of a malignant brainstem, cerebellar, and CPA tumor.The link to the video can be found at: https://youtu.be/AIGebJPJEnw.

Objectives The video demonstrates the steps for an endoscopic transnasal approach for resection of the odontoid causing platybasia with basilar invasion. Design The video reviews the clinical presentation, preoperative workup and imaging, patient positioning, technical nuances of the procedure, reconstruction, and clinical outcomes including postoperative imaging. Setting The surgery was performed by a skull base team including otolaryngologists and neurological surgeons at a large regional tertiary care facility. Participants A 59-year-old female with the Chiari I malformation with history of multiple revision cervical spinal surgeries presents with neck pain. Preoperative imaging showed a hypoplastic clivus and platybasia with basilar invasion. Main Outcome Measures The main outcome measures consist of safely removing the odontoid with appropriate closure, reversal of the patient symptoms, and prevention of both operative complications and ventral compression of the brainstem. Results The patient's neck pain improved. There were no intraoperative or postoperative complications besides anterior rightward nasal septal deviation causing unilateral nasal obstruction. A septoplasty was performed to correct the septal deviation 6 months after the initial procedure. Conclusions The endoscopic transnasal approach to the resection of odontoid is a safe and effective treatment to address basilar invasion and ventral compression of the brainstem.The link to the video can be found at: https://youtu.be/m_c3-Vn-l80.

Expanded endonasal endoscopic approaches provide access to the entire central skull base and craiocervical junction. The authors present a case of an 81-year-old man who presented with progressive spastic quadriparesis to the point of being wheel-chair bound. Cervical spine computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated multilevel extensive spondylitic changes with a large pannus at the C1–2 junction, severely compressing the spinal cord (Figs. 1 and 2). Given the significant anterior spinal cord compression and the patient's substantial weakness, the decision was made to perform an endoscopic endonasal anterior cervical decompression and resection of the pannus followed a posterior cervical fusion. The patient recovered well following surgery with significant improvement of motor function. The preoperative assessment, the step-by-step surgical technique, and the technical nuances are demonstrated and discussed.The link to the video can be found at: https://youtu.be/HzrZO-0Vol4.

Aneurysms of the posterior circulation pose a unique challenge due to higher rupture rates, higher recurrence rates following endovascular treatment, and extended open cranial base approaches required to reach the ventrally located brainstem circulation. While endovascular therapy has made tremendous strides in successful treatment for most posterior circulation aneurysms, open microscopic approaches remain essential in specific circumstances. Here, we present a case of a patient who presented with acute, severe headache, and sixth nerve palsies, and who was found to have hydrocephalus and a dissecting aneurysm at the anterolateral medullary segment of the posterior inferior cerebellar artery (PICA). Interestingly, this patient had a history of alpha-1 antitrypsin deficiency that has been linked with spontaneous aortic and cervical arterial dissections. The fusiform geometry of the dissecting aneurysm was deemed suboptimal for endovascular treatment, so an open microsurgical approach for occipital artery to PICA bypass and aneurysm trapping was planned. Because this patient had cerebral edema in the setting of a ruptured aneurysm and hydrocephalus, a far lateral craniotomy combined with drilling of the occipital condyle and jugular tubercle was critical to enhance exposure of the first segment of the PICA and to minimize brain retraction. In this video, we highlight the key steps and nuances for harvest of the occipital artery, achieving control of the extracranial vertebral artery, performing the transcondylar and transtubercular far lateral approach, and bypass with trapping technique for these challenging posterior circulation aneurysms.The link to the video can be found at: https://youtu.be/dqgblwX6t0Q.

C1 fractures with an intact transverse ligament are usually treated conservatively. Patients who present with a progressive diastasis of bone fragments and a progressive articular subluxation mainly attributed to progressive lengthening of the transverse ligament (TAL) fibers can be treated with a C1 “C-clamp” fusion.A 75-year-old male who sustained a motor vehicle accident was neurologically intact. A computed tomography (CT) imaging demonstrated a Jefferson's type-C1 fracture with a slight lateral displacement of the C1 left lateral mass (LM) and a rotatory subluxation on the right. MRI showed an intact TAL and demonstrated an isolated rupture of the left alar ligament. Conservative treatment was chosen. Radiographic follow-up showed, at 3 months, progressive lateral mass displacement, most likely due to elongation of the TAL fibers; this was also associated with a persistent mechanical neck pain. For this reason, we performed a posterior reduction and internal fixation in a C-clamp fashion by placement of C1 lateral mass screws and posterior compression sparing the C1–2 joint. Using navigation, a 3.5-mm screw was inserted into the LM bilaterally. The screw heads were then connected with a rod and compression was applied before tightening. Postoperative CT scan demonstrated a satisfying reduction and further imaging will be made during the follow-up. The patient had a considerable relief of neck pain. Simple lateral mass fixation with C-clamp technique is a reasonable option in case of isolated C1 fractures in patients who have failed conservative management while preserving the range of motion (ROM) at the atlanto–axial joint.The link to the video can be found at: https://youtu.be/x8bsVwzCt_M.

Objective Transoral odontoidectomy in the treatment of basilar invagination is surgically challenging. Incision of the soft palate significantly increases rostral exposure of the clivus but is associated with a high incidence of speech and swallowing difficulties after surgery. We present a patient suffering from severe compression of the medulla oblongata due to an extreme form of basilar invagination treated successfully with the resection of dens via a transoral nasopharyngeal approach without palatotomy. Setting Microsurgical endoscopic-assisted odontoidectomy through a transoral epipharyngeal approach was performed with subsequent craniocervical stabilization in a 21-year-old patient suffering from progressive myelopathy due to compression of the medulla oblongata and associated progressive syringomyelia. Results The 21-year-old man was initially treated with suboccipital craniotomy and duroplasty in another institution. After initial improval he subsequently developed progressive ataxia, dysphagia, a bulbar speech, and weakness of the extremities. Beside ventral compression, he developed a secondary Chiari's malformation and a holospinal syringomyelia. Resection of the dens was successfully accomplished via a microsurgical transoral epipharyngeal endoscopic-controlled odontoidectomy without palatotomy. One week after odontoidectomy, posterior craniocervical stabilization was performed. All preoperative symptoms and signs improved significantly and the patient leads an independent life 4 years after odontoidectomy. On follow-up magnetic resonance imaging (MRI), the syringomyelia completely resolved. Conclusions Palatotomy with its potential adverse effects can usually be avoided even for the treatment of extreme forms of basilar invagination.The link to the video can be found at: https://youtu.be/CBKE4n94W4g.

Objectives This study was aimed to describe a far lateral approach for microsurgical resection of a transverse ligament cyst, with emphasis on the microsurgical anatomy and technique. Design A far lateral craniotomy is performed in the lateral decubitus position. After opening the dura laterally, dural sutures are placed for retraction. A stitch placed through the dentate ligament is advantageous to rotate the spinal cord to allow access to the ventral cyst. The cyst is marsupirlized and mass effect on the spinal cord is relieved. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The first author performed the surgery and edited the video. Chart review and literature review were performed by the other authors. Outcome Measures Outcome was assessed with postoperative neurological function. Results The patient was discharged home after an uneventful hospital course. At short-term follow-up, the patient had a significant improvement in postoperative strength. Conclusion The far lateral approach provides an adequate corridor to the ventrolateral brainstem in combination with utilization of the dentate ligament to reach ventral cysts compressing the spinal cord. An adequate understanding of the relevant microsurgical anatomy is a key to safe surgery in this region.The link to the video can be found at: https://youtu.be/5MGVPO2Q2pI.

We present a case of a sizeable foramen magnum meningioma that was resected through a C1 hemilaminectomy in prone (concorde) position. The patient is a 51-year-old woman with a 3-month history of progressive paresthesia of the upper and lower extremities, followed by gait disturbance, and hand apraxia. There was no complaint of nuchal pain.On magnetic resonance imaging (MRI) a briskly enhancing extra-axial, intradural craniospinal lesion, extending from the basion of the lower clivus, over the tectorial membrane to the middle of the axis' body was discovered. There was significant transposition and compression of the medulla and corresponding focal hyperintensity on T2-weighted imaging.On physical examination, the patient was ambulatory independently, notwithstanding a pronounced spinal ataxia. There were deficits in sensation and proprioception, as well as urinary retention, but preserved function of the lower cranial nerves.In view of the profound transposition of the medulla, utilization of the corridor created by the tumor seemed feasible and we felt that a limited C1 hemilaminectomy would provide sufficient microsurgical access thus obviating a more extensive and invasive approach to the craniocervical junction.A gross-total resection was achieved; histopathology confirmed a World Health Organization (WHO) grade I angiomatous meningioma with a low-proliferation index. The patient was discharged home 3 days after surgery and her spinal ataxia resolved completely within 3 months of out-patient rehabilitation. At 3-year follow-up, there was no indication of residual or recurrence.The link to the video can be found at: https://youtu.be/WyShbfr-xi0.

Objectives We illustrate endoscopic endonasal odontoidectomy for the Chiari-I malformation respecting craniovertebral junction (CVJ) stability. Design Case report of a 12-year-old girl affected by the Chiari-I malformation. Magnetic resonance imaging (MRI) showed tonsillar herniation, basilar invagination, and dental retroversion, causing angulation and compression of the bulbomedullary junction. Patient underwent endoscopic third ventriculostomy (ETV) with reduction of ventricular size and resolution of gait disturbances, but she complained the Valsalva-induced headaches, hiccup, and dysesthesias in the lower limbs. Endoscopic endonasal odontoidectomy was chosen to decompress the cervicomedullary junction. Setting The research was conducted at University Hospital “Ospedale di Circolo,” Department of Neurosurgery at Varese in Italy. Participants Patients were from neurosurgical and ENT (ear, nose, and throat) skull base team. Main Outcome Measures A bilateral paraseptal approach was performed, using a four-hand technique. After resection of posterior edge of the nasal septum, the choana is entered and a rhinopharynx muscle–mucosal flap is dissected subperiosteal and transposed in oral cavity. The CVJ is exposed and, using neuronavigation and neuromonitoring, odontoidectomy is fulfilled until dura is reached, preserving the anterior arch of C1. Reconstruction is obtained suturing the flap previously harvested. Results Postoperative course was unremarkable and the patient experienced improvement of symptoms. Postoperative MRI documented the appearance of tight cerebrospinal fluid (CSF) film anterior to bulbomedullary junction and in retrotonsillar spaces, opening of the bulbomedullary angle, and slight tonsils reduction. No CVJ instability was occurred with any need of posterior fixation. Conclusion Endoscopic endonasal odontoidectomy is a feasible approach for CVJ malformation. In this case, bulbar decompression was achieved preserving CVJ stability and avoiding posterior fixation.The link to the video can be found at: https://youtu.be/VIobocHfCuc.

Objectives This study describes a far lateral approach for the resection of a recurrent fibromyxoid sarcoma involving the ventrolateral brainstem, with emphasis on the microsurgical anatomy and technique. Design A far lateral craniotomy is performed in the lateral decubitus position and the transverse and sigmoid sinuses exposed. After opening the dura, sutures are placed to allow gentle mobilization of the sinuses. The recurrent tumor is immediately visible. The involved dura is resected and aggressive internal debulking is performed. Subarachnoid dissection gives access to the lower cranial nerves. The tumor is dissected off the affected portions of the brainstem. A dural graft is used to reconstitute the dura. Photographs of the region are borrowed from Dr. Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior author performed the surgery. The video was edited by Dr. V.N. chart review, and literature review were performed by Drs. W.M. and J.B. Outcome measures Outcome was assessed with the extent of resection and postoperative neurological function. Results A near gross total resection of the lesion was achieved. The patient developed a left vocal cord paresis, but her voice was improving at 3-month follow-up. Conclusion Understanding the microsurgical anatomy of the craniocervical junction and ventrolateral brainstem and meticulous microneurosurgical technique are necessary to achieve adequate resection of lesions involving the ventrolateral brainstem. The far lateral approach provides an adequate corridor to this region.The link to the video can be found at: https://youtube/uYEhgPbgrTs.

This video demonstrates the transmastoid suprajugular approach with neck dissection to a solitary fibrous tumor involving the jugular foramen and upper cervical region. This patient was a 39-year-old man who presented with dysphagia and cranial nerve (CN) XI and CN XII palsies. Imaging revealed a large homogenously enhancing lesion involving the jugular foramen and extending into the retropharyngeal space (Fig. 1). Radiographic findings supported a diagnosis of jugular foramen schwannoma. After an initial period of observation, the tumor demonstrated significant growth, and the patient agreed to proceed with surgery. The suprajugular approach allowed for exposure and resection of the tumor without mobilization of the facial nerve. The patient had an excellent clinical outcome with House–Brackmann grade-1 facial function, safely tolerated a regular diet, had intact CN XI function, and had a stable CN XII palsy (Fig. 2). Pathology findings identified the tumor as a hemangiopericytoma World Health Organization grade 1 (solitary fibrous tumor).The link to the video can be found at: https://youtu.be/C4sPyHcLMA0.

This video illustrates the case of a 52-year-old man with a history of multiple bleeds from a lateral midbrain cerebral cavernous malformation, who presented with sudden-onset headache, gait instability, and left-sided motor and sensory disturbances. This lesion was eccentric to the right side and was located in the dorsolateral brainstem. Therefore, the lesion was approached via a right-sided extreme lateral supracerebellar infratentorial (exSCIT) craniotomy with monitoring of the cranial nerves. This video demonstrates the utility of the exSCIT for resection of dorsolateral brainstem lesions and how this approach gives the surgeon ready access to the supracerebellar space, and cerebellopontine angle cistern. The lateral mesencephalic safe entry zone can be accessed from this approach; it is identified by the intersection of branches of the superior cerebellar artery and the fourth cranial nerve with the vein of the lateral mesencephalic sulcus. The technique of piecemeal resection of the lesion from the brainstem is presented. Careful patient selection and respect for normal anatomy are of paramount importance in obtaining excellent outcomes in operations within or adjacent to the brainstem.The link to the video can be found at: https://youtu.be/aIw-O2Ryleg.

Trigeminal neuralgia is a chronic pain disorder affecting the face. In approximately 80% of cases, it is most commonly caused, when the root entry zone (REZ) of the trigeminal nerve is compressed by the superior cerebellar artery (SCA). The etiology of the remaining 20% of cases is distributed among venous, arteriovenous malformations, posterior fossa tumors, multiple sclerosis plaque compressions, and other pathologies. Combinations of those compressive factors are very rare.1 2 3 4 Herein, we present a video clip of microvascular decompression (MVD) in a 73-year-old female, who has failed conservative treatment with 6 medications over 10 years. She was affected by a unique triple compression of the right REZ by the SCA, anterior inferior cerebellar artery (AICA), and petrosal vein complex (Fig. 1A). Right-sided microsurgical decompression of the REZ of the trigeminal nerve through standard retrosigmoid craniotomy was performed by the senior author (K.I.A.). The SCA and AICA were separated from the nerve using Teflon pledgets. The petrosal vein complex was coagulated and divided, freeing up the right trigeminal nerve (Fig. 1B). The patient was discharged home on the third postoperative day with complete resolution of trigeminal neuralgia.The link to the Video can be found at: https://youtu.be/PYVvImGW0yE.

Ventral masses of the craniocervical junction threaten the medulla and upper spinal cord leading to lower cranial nerve dysfunction and myelopathy. Traditional transoral and newer endonasal approaches can access ventral pathology in this region, though both remain challenging due to the competing goals of achieving sufficient decompression, yet mitigating risk to nearby critical neurovascular structures. Transoral approaches have traditionally been avoided for degenerative pseudotumor which generally slowly regresses following posterior fixation. Here, we present two cases of patients with significant retroodontoid degenerative pseudotumor and pannus causing dysphagia and myelopathy. The first patient was found with a large broad pannus requiring a wide decompression extending from lower clivus to inferior aspect of the C1 arch and odontoid process. The second patient had a more focal mass effect due to pannus and synovial cyst at the level of the inferior half of C1 and midodontoid. Both patients underwent an endoscopic endonasal transodontoid approach for immediate decompression followed by a posterior C1–C2 fusion. In these surgical videos, we highlight anatomic considerations in this critical area, demonstrate nuances of technique, and outline strategies to avoid complications and maximize exposure.The link to the video can be found at: https://youtu.be/19I-GQYGIr4.

Introduction A variety of dural openings are described for frontal–temporal and cranio-orbital craniotomies. As with any surgical technique, the goal is to optimally and safely address the pathology, minimize normal anatomy disruption, and optimize postoperative recovery. This study reports a modified dural opening for frontal–temporal approaches which minimizes brain exposure while facilitating visualization for neoplastic and vascular lesions of the anterior clinoid, supra- and parasellar and adjacent regions. Methods A sample case is presented for which a low subfrontal dural exposure was utilized for tumor resection. The clinical presentation, surgical procedure, and outcome are summarized including a video detailing the surgical technique. Results A 63-year-old female with gradual left eye vision loss and tumor enlargement on serial imaging. The small dural-based tumor arose from the left anterior clinoid and optic canal region compressing the optic nerve. The video shows a left frontal–temporal craniotomy used to perform extradural anterior clinoidectomy and optic canal decompression. The novel low subfrontal dural opening without fixed brain retraction allowed dural opening around the optic canal and clinoidectomy region to resect tumor and complete optic nerve decompression. Postoperatively, the patient did well with significant recovery of vision and follow-up at 2.5 years shows no evidence of tumor recurrence. Conclusion The novel low subfrontal dural opening provides access to lesions of the supra-and para-sellar and adjacent regions, and preservation of much of the dura avoids some of the risks of intradural dissection including Sylvian fissure dissection and brain retractionThe link to the video can be found at: https://youtu.be/Jc7wvR4PTFk.

Unilateral suprasellar meningiomas have distinct features compared to other midline tumors, as they may produce severe visual symptoms even if small due to an early involvement of the optic canal. Surgical treatment of these tumors from an ipsilateral approach is challenging, as the tumor is covered by the optic nerve that needs to be mobilized to access the optic canal extension. A contralateral approach allows a direct line of sight to the tumor despite a longer working distance. We report the case of a 49-year-old patient presenting with unilateral visual loss related to a left suprasellar meningioma extending to the left optic canal and displacing the optic nerve laterally. Through a right eyebrow approach, a 2.5/2 cm supraorbital bone flap was raised and the orbital floor was thoroughly flattened. After dural opening, the carotid cistern was opened and CSF evacuated allowing a surgery without fixed retractors. The intracranial part of the tumor was removed, but the optic nerve seemed to be still displaced by the intracanalicular part. Under copious irrigation, the medial part of the optic canal was drilled, the dura incised, and the tumor removed. Postoperative course was favorable and the patient made a complete visual recovery. Postoperative MRI showed complete removal of the tumor. We present different surgical steps and discuss the nuances of the procedure. The contralateral eyebrow approach is an interesting addition to the surgical armamentarium and should be discussed for unilateral suprasellar tumors.The link to the video can be found at: https://youtu.be/2LTEOaGoKzo.

Objectives To discuss the use of the posterior petrosal approach for the resection of a retrochiasmatic craniopharyngioma. Design Operative video. Results In this case video, the authors discuss the surgical management of a large craniopharyngioma, presenting with mass effect on the third ventricle and optic apparatus. A first surgical stage, through an endoscopic endonasal transtubercular approach, allowed satisfactory decompression of the optic chiasma and nerves in preparation for adjuvant therapy. However, accelerated growth of the tumor, with renewed visual deficits and mass effect on the hypothalamus and third ventricle, warranted a supplementary resection. A posterior transpetrosal1 2 (also called “retrolabyrinthine transtentorial”) was performed to obtain a better exposure of the tumor and the surrounding anatomy (floor and walls of the third ventricle, perforating vessels, optic nerves, etc.)3. Nuances of technique and surgical pearls related to the posterior transpetrosal are discussed and illustrated in this operative video, including the posterior mobilization of the transverse–sigmoid sinuses junction, preservation of the venous anatomy during the tentorial incision, identification and preservation of the floor of the third ventricle during tumor resection, and a careful multilayer closure. Conclusion Retrochiasmatic craniopharyngiomas are difficult to reach tumors that often require skull base approaches, either endoscopic endonasal or transcranial. The posterior transpetrosal approach is an important part of the surgical armamentarium to safely resect these complex tumors.The link to the video can be found at: https://youtu.be/2MyGLJ_v1kI.

Surgery for craniopharyngiomas can be challenging due to the involvement of multiple critical neurovascular structures. The expanded endoscopic endonasal approach can provide superior access to suprasellar craniopharyngiomas, particularly with retrochiasmatic extension and significant hypothalamic involvement. We describe the surgical technique used to treat a 30-year-old patient who presented with 4 weeks of worsening vision, fatigue, and memory loss. His vision was counting fingers at 1 feet on the right and 20/800 on the left with a temporal hemianopsia. Laboratory evaluation demonstrated central hypoadrenalism, hypothyroidism, and hypogonadism. Imaging showed a large solid and cystic suprasellar mass. The transtubercular approach with removal of the lateral tubercular strut can provide wide bilateral access to the opticocarotid region. The superior intercavernous sinus must be coagulated and ligated. Initial arachnoid dissection is centered at the midline, mobilizing the superior hypophyseal branches to the optic apparatus laterally. The cyst capsule is opened and care is taken to minimize spillage of cyst fluid into the subarachnoid space. Central debulking and then extracapsular dissection is performed under direct visualization using sharp dissection. Reconstruction of the dura is performed with an inlay/onlay fascia lata button that is held together with four sutures that hold the graft edges against the native dural edges. This is followed by vascularized nasoseptal flap reconstruction. No lumbar drain or nonabsorbable packing is required. The patient's vision had dramatic improvement and by 1 week postoperatively was 20/20 with full visual fields. Postoperative diabetes insipidus was managed with nasal desmopressin. Postoperative MRI demonstrated complete removal.The link to the video can be found at: https://youtu.be/QQxCNUcq1qg.

Ependymoma is one of the most common pediatric tumors in central nervous system, for which gross total resection has been the most favorable prognostic factor.1 2 However, surgery of ependymomas located in brain stem is significantly challenging. This video demonstrates the microsurgical removal of an ependymoma originating from ependymal cells of the lateral recess of fourth ventricle via retrosigmoid approach in an 11-year-old female. The patient presented with a 6-month history of continues headache and vomiting. On examination, she had a walking instability and an emaciated body. Neuroimaging revealed a right lateral pontine lesion extending to the cerebellopontine angle region. The patient underwent a suboccipital craniotomy, followed by excellent exposure for the tumor. Petrosal vein encased by the tumor mass and close adhesion of the tumor and the initial segments of facial and acoustic nerves adjoined brain stem could be seen operatively. While preserving trigeminal nerve, facial and acoustic nerves, posterior cranial nerves, anterior inferior cerebellar artery, labyrinth artery, posterior inferior cerebellar artery, and petrosal vein, gross total resection was achieved under the careful operation along arachnoid spaces together with intratumoral decompression. The patient tolerated the procedure well without any neurological deficits. Histological examination confirmed the tumor as an ependymoma (WHO II). The cytology measurement of the cerebrospinal fluid did not find any tumor cells. Postoperative computed tomography and magnetic resonance imaging scan depicted complete resection of the tumor, and adjuvant radiotherapy was recommended. She remained symptom-free without any evidence of recurrence during the follow-up period of 1 year. Informed consent was obtained from the patient.The link to the video can be found at: https://youtu.be/sZ9GhUeltwc.

We present a case of a medium-sized foramen magnum meningioma that was resected through a midline suboccipital subtonsillar approach with C1 laminectomy in prone (Concorde) position. The patient is a 77-year-old woman with a 6-month history of intermittent vertigo, moderate gait instability, and slight decline of memory.On magnetic resonance imaging (MRI) an extra-axial intradural lesion was discovered that originated from the right epicondylar region just inferior to the jugular tubercle and occupied the anterolateral aspect of the foramen magnum. There was moderate transposition and compression of the medulla at the level of the cerebellar tonsils.On physical examination the patient was ambulatory independently without motor weakness but exhibited some gait instability. The function of the lower cranial nerves was preserved.A gross-total resection was achieved, histopathology confirmed a WHO grade-I meningothelial meningioma with a low-proliferation index. The patient was discharged home 5 days after surgery, her gait instability improved significantly immediately after surgery and had resolved completely after 2 weeks of inpatient rehabilitation. There was no other neurological deficit. At 3-month follow-up MRI, there was no indication of meningioma residual or recurrence.In summary, the midline suboccipital subtonsillar approach is a powerful tool with limited morbidity in the armamentarium for the microsurgical management of a variety of pathologies residing in the posterior cranial fossa and the craniocervical junction. Oftentimes the space created by the pathology opens up corridors that can be exploited for microsurgical access to avoid more extensive surgical approaches.The link to the video can be found at: https://youtu.be/0uUxs13ze7w.

We present a case of a sizeable vagal schwannoma that was resected through a lateral suboccipital approach in semisitting position. An extra-axial lesion, occupying the left cerebellomedullary cistern and extending from the pontomedullary junction to the jugular foramen was incidentally discovered in a 40-year-old woman afflicted with secondary progressive multiple sclerosis during repeated magnetic resonance imaging (Fig. 1). On physical examination, a mild deviation of the uvula to the right and a diminished gag reflex were observed. The patient was referred to our department after considerable growth of the lesion was noted and a broad interdisciplinary consensus was reached to treat the lesion surgically.A gross total resection was achieved, histopathology confirmed a WHO I schwannoma with a low proliferation index. Postoperative dysphonia resolved completely within a few weeks, there was no collateral neurological deficit and especially no functional dysphagia. At 3-year follow-up, there was no indication of residual or recurrence.This 2-dimensional video demonstrates pre- and postoperative imaging, positioning and set-up of operating room, anatomical and surgical nuances of the skull base approach, and the operative technique for microdissection of the schwannoma from the critical neurovascular structures (Fig. 2).In summary, the lateral suboccipital approach in semisitting position is a powerful tool in the armamentarium for the microsurgical management of various pathologies residing in the posterior cranial fossa, especially large and vascularized schwannomas. Provided the necessary anesthesiological precautions and intraoperative procedures the semisitting position is safe and effective.The link to the video can be found at: https://youtu.be/-9o_qJGkQhg.

Tumors located in the craniocervical junction region are significantly challenging for surgical resection. We shared our experience of a meningioma at craniocervical junction resected through far lateral approach in a 68-year-old female. The patient presented with intermittent headache with discomfort in the neck and shoulders for 3 years without any positive signs. Magnetic resonance imaging (MRI) revealed a tumor of 3.6 cm × 3.0 cm × 2.5 cm lying at the ventral side of medulla oblongata, with T1 hypointensity, T2 hyperintensity, and a significant enhancement on T1-contrast image. The far lateral approach on the right side was planned to resect the tumor with a park-bench position. The patient underwent a standard craniotomy using a lazy S-shaped incision. The transposition of vertebral artery was performed carefully therein, followed by removal of part of the arches of atlas and axis. After exposure of the tumor, vertebral artery (VA) and posterior inferior cerebellar artery (PICA) adhesive to the lesion could be seen operatively. Truncating the supplying blood vessels of the tumor was taken as the first step, followed by resecting the tumor mass in a piecemeal manner. While preserving VA, PICA, posterior nerves, medulla oblongata, and cervical cord, gross-total resection was achieved under the careful operation. The patient tolerated the procedure well without any neurological deficits. Histological examination confirmed the tumor as a meningioma (World Health Organization [WHO] grade I). Postoperative MRI scan depicted complete resection of the tumor. The patient remained symptom free without any evidence of recurrence during the follow-up period of 1 year. Informed consent was obtained from the patient.The link to the video can be found at: https://youtu.be/i9H-wS4fF10.

Objectives To describe a far lateral approach for microsurgical clipping of a ruptured posterior inferior cerebellar artery (PICA) aneurysm involving the hypoglossal nerve, with emphasis on the microsurgical anatomy, and technique. Design A far lateral craniotomy is performed in the lateral decubitus position and the transverse and sigmoid sinuses were exposed. After opening the dura, sutures are placed to allow gentle mobilization of the sinuses. The ipsilateral cerebellar tonsil is mobilized and the PICA is followed to its junction with the vertebral artery. Hypoglossal nerve rootlets are draped over the dome of the aneurysm. Mobilization of the PICA and the hypoglossal nerve away from the lateral medulla allows microsurgical clipping of the aneurysm neck. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior authors performed the surgery. The video was edited by Drs. V.N. and J.B. Chart review and literature review were performed by Drs. W.M. and J.B. Outcome Measures Outcome was assessed with successful clip occlusion and postoperative neurological function. Results There was complete clip occlusion of the PICA aneurysm with no postoperative neurological deficits. The patient was discharged home after an uneventful hospital course. Conclusion The far lateral approach provides an adequate corridor to the ventrolateral brainstem for microsurgical treatment of PICA aneurysms. An adequate understanding of the relevant microsurgical anatomy is the key to safe and effective clipping in this region.The link to the video can be found at: https://youtu.be/yhjKRIG5H74.

Objectives The complex anatomical relationships of neurovascular structures at the craniovertebral junction make the clipping of a posterior inferior cerebellar artery (PICA) aneurysm surgically challenging. We demonstrate the clipping of a PICA aneurysm in the video. Design, Setting, and Participant A 65-year-old woman presented with a nonsymptomatic unruptured left PICA aneurysm; follow-up angiography showed an increase in its size. Preoperative angiography demonstrated a PICA aneurysm with the neck close to the origin of the PICA. A daughter sac of the aneurysm was also noted. A left far lateral approach was performed. The vagoaccessory triangle was exposed after opening the arachnoid membrane. The origin of the PICA and the aneurysm were revealed after exploration. The aneurysm neck was identified both proximally and distally. Two fenestrated clips were applied; subsequent indocyanine green (ICG) videoangiography demonstrated that the PICA was obstructed. One clip was adjusted, and repeated ICG videoangiography showed the PICA was patent. An endoscope was used before and after the clip application to better understand the anatomy of the aneurysm and inspect clip positions (Fig. 1). Outcome The patient was neurologically intact postoperatively and was discharged on postoperative day 4. Conclusion PICA aneurysms require careful treatment. Impingement of adjacent structures can cause severe complications. Lower cranial nerve damage can cause dysphagia, and compromised vertebral/PICA circulation can cause brainstem symptoms, such as Wallenberg's syndrome. Intraoperative ICG videoangiography should be used to evaluate vessel patency, and the endoscope should be used to fully inspect the aneurysm and evaluate the clip application.The link to the video can be found at: https://youtu.be/dKxFQTRA89g.

In this operative video atlas manuscript, the authors demonstrate the operative nuances and surgical technique for endoscopic-assisted microvascular decompression of a large ectatic vertebral artery causing hemifacial spasm. A retrosigmoid approach was performed and a large ectatic vertebral artery was transposed away from the root exit zone of cranial nerve VII (Fig. 1). The lateral spread response disappeared, signifying adequate decompression of the facial nerve (Fig. 2). The use of endoscopic-assistance during the microsurgical decompression was very useful to confirm the origin and also the resolution of neurovascular conflict. Postoperatively, the patient experienced immediate resolution of hemifacial spasm with normal facial nerve and hearing function. Written consent was obtained from the patient to publish videos, photographs, and images from the surgery.The link to the video can be found at: https://youtu.be/RlMz44uCDCw.

Objective Surgical treatment of foramen magnum (FM) meningiomas is challenging due to proximity of the tumor to critical neurovascular structures, namely, the lower brainstem/upper cervical cord, vertebral artery, PICA, and lower cranial nerves. Controversies in microsurgical resection of meningiomas in this location include the necessity for condyle drilling and the need for vertebral artery mobilization. However, a laminectomy or hemilaminectomy of the C1 posterior arch is usually routinely performed. We herein present microsurgical, endoscopic-controlled resection of a FM meningioma via a posterolateral retrocondylar suboccipital craniotomy with preservation of the integrity of the posterior arch of the atlas. Setting Our patient, a 57-year-old patient, suffered from right-sided hemiparesis due to a right-sided ventrolateral FM meningioma compromising the medulla oblongata and upper cervical cord. The tumor at the craniocervical junction was resected through a posterolateral suboccipital retrocondylar craniotomy. Results Radical resection of the FM meningioma was accomplished via a lateral suboccipital retrocondylar craniotomy with preservation of posterior arch of atlas integrity. The postoperative course was uneventful with full preservation of neurological function. Preoperative hemiparesis subsided completely after surgery. Conclusion Anterior-laterally located FM meningiomas can be safely and completely resected via a suboccipital retrocondylar craniotomy. A laminectomy or hemilaminectomy of the posterior arch of C1 is not routinely required for complete and safe resection of these tumors at the craniocervical junction. Neuroendoscopy is beneficial for control of complete tumor resection.The link to the video can be found at: https://youtu.be/DBk6qoJ6OzQ.