Microneurosurgery for Ruptured Aneurysm of Distal Intracranial Vertebral Artery: A Case Report.

The International Subarachnoid Aneurysm Trial led to a shift from clipping to endovascular coiling as the primary therapy for cerebral aneurysm particularly in the management of posterior circulation aneurysm. However, endovascular therapy is often unavailable in low-resource settings, emphasizing the importance of maintaining surgical skill sets in resource-poor countries. This article presents a detailed case report on the successful microneurosurgical management of a 65-year-old female with a history of headache and weakness with past history of hypertension and a right posterior cerebral artery territory infarct who was diagnosed with a ruptured aneurysm situated within the intracranial vertebral artery. Patient was operated with the far lateral approach and clipping of the aneurysm. This case report elucidates the intricate surgical techniques employed, and the challenges neurosurgeons encountered in treating posterior circulation intracranial aneurysms, particularly those with ruptured complications. The aneurysms' intricate anatomy and increased rupture risk necessitate a meticulous microneurosurgical approach. The severity of subarachnoid hemorrhage from ruptured aneurysms increases morbidity and mortality rates.

Surgical management of a foramen magnum tumor via a far-lateral approach using an oblique straight incision: a case series report and technique note.

Objective: To review our single-institution experience in the surgical management of foramen magnum tumors via a far-lateral approach using an oblique straight incision. Methods: From October 2023 to January 2024, four cases of tumors in the foramen magnum area treated at the Capital Medical University-affiliated XuanWu hospital neurosurgery department were involved in this study. All cases were managed with a far-lateral approach using an oblique straight incision. We retrospectively reviewed the clinical and imaging data, as well as the surgical strategies employed. Results: Three cases of foramen magnum meningiomas and one case of glioma of the ventral medulla. All cases underwent a far-lateral approach using an oblique straight incision; all cases had a gross total resection, and the wounds healed well without cerebral fluid leakage or scalp hydrops. Except for one case of right foramen magnum meningioma, which had dysphagia and pneumothorax, the other cases were without any postoperative complications. Conclusion: A far-lateral approach using an oblique straight incision can preserve muscle integrity and minimize subcutaneous exposure, allowing for complete anatomical reduction of muscles. This craniectomy method is simple and replicable, making it worthy of further clinical practice.

Lateral medullary vascular compression manifesting as paroxysmal hypertension.

Neurovascular compression of the rostral ventrolateral medulla (RVLM) has been described as a possible cause of refractory essential hypertension. We present the case of a patient affected by episodes of severe paroxysmal hypertension, some episodes associated with vago-glossopharyngeal neuralgia. Classical secondary forms of hypertension were excluded. Imaging revealed a neurovascular conflict between the posterior inferior cerebellar artery (PICA) and the ventrolateral medulla at the level of the root entry zone of the ninth and tenth cranial nerves (CN IX-X REZ). A MVD of a conflict between the PICA and the RVLM and adjacent CN IX-X REZ was performed, resulting in reduction of the frequency and severity of the episodes. Brain MRI should be performed in cases of paroxysmal hypertension. MVD can be considered in selected patients.

Far lateral approach for dumbbell-shaped C1 schwannomas: how I do it.

BACKGROUND: Dumbbell-shaped C1 schwannomas are rare lesions that involve both intra- and extradural compartments. Because of the intimate relationships these lesions develop with the third and fourth segments of the vertebral artery, surgical removal of these lesions remains a challenge. METHOD: We describe the key steps of the far lateral approach for dumbbell-shaped C1 schwannomas with a video illustration. The surgical anatomy is described along with the techniques for protecting the vertebral artery. CONCLUSION: Dumbbell-shaped C1 schwannomas can be safely removed by using the far lateral approach, surgical anatomy expertise, and intraoperative microvascular Doppler.

Far Lateral Approach: "Trans-tumor Approach" on Huge Dumbbell-Shape Neurofibroma of Anterior Foramen Magnum Without Craniectomy-Anatomical Consideration and New Trend.

The foramen magnum approach is always challenging because of the relationships between vital neurovascular structures in this area. Several approaches have been described, among them, the far lateral approach remains a cornerstone for the resection of anterior or anterolateral processes of the foramen magnum. This approach displays two main steps: the first is cervical, whereas the second is cranial.We report the case of a 63 year-old woman admitted for a progressive quadriplegia with swallowing disorders revealing a process of the anterior and anterolateral part of the foramen magnum. A cervical step of a far lateral approach without opening the foramen magnum achieved a near total resection of the process via a trans-tumor corridor and confirmed a dumbbell shape neurofibroma. The postoperative period showed a resolution of swallowing disorders and a progressive improvement of muscular strength. At 8 months follow-up, she was asymptomatic and able to walk with a normal balance. The surgical technique and anatomical correlation of this trans-tumor approach are discussed.

An Orientational Harvesting Occipital Artery Technique via far Lateral Approach: A Cadaveric Study.

OBJECTIVE: To provide further information on the identification of the occipital artery (OA) and suggest an improved approach to its anterograde dissection technique for harvesting. METHODS: Six cadaveric specimens were prepared for surgical simulation, and the anterograde approach was used to harvest the OA; a hockey stick incision was made from the C2 spinous process through the nuchal ligament to the mastoid tip. By retracting the scalp flap from the posterior arch of C2 to the transverse process, the suboccipital triangle was reflected by a single myocutaneous flap from the inferior nuchal line. In addition, 70 head computed tomography angiography scans were assessed bilaterally (n = 140) to study the running pattern of the OA. RESULTS: The mean total length of the mobilized OA was 11.8 ± 0.7 cm, with a diameter of 1.5 ± 0.1-2.1 ± 0.2 mm at the suboccipital segment and 1.3 ± 0.1 mm at the upper edge of the surgical incision. The average distance of OA at the inferior nuchal line to the midline was 2.9 ± 0.3 cm, the average distance of OA at the superior nuchal line to midline was 4.1 ± 0.2 cm, the average distance of OA at incision edge to midline was 5.2 ± 0.3 cm. CONCLUSION: Orientational anterograde technique for OA harvesting is a fast and easy approach. This approach avoids critical neurovascular structures. The most important step is to identify the OA near the lateral edge of the superior oblique muscle. Subsequently, in conjunction with preoperative computed tomography angiography, an imaginary line that crosses the inferior and superior nuchal lines may be established to assist in the separation of the OA.

A Contemporary Clinico-Anatomical Guide to Craniovertebral Junction Surgery.

Background Surgical treatment of ventral and ventrolateral lesions of the craniocervical junction are among the most challenging neurosurgical pathologies to treat. Three surgical techniques, the far lateral approach (and its variations), the anterolateral approach, and the endoscopic far medial approach can be used to approach and resect lesions in this area. Objective The aim of the study is to examine the surgical anatomy of three skull base approaches to the craniocervical junction and review surgical cases to better understand the indications and possible complications for each of these approaches. Methods Cadaveric dissections with standard microsurgical and endoscopic instruments were performed for each of the three surgical approaches, and key steps and surgically relevant anatomy were documented. Six patients with appropriate pre-, post-, and intraoperative imaging and video documentation are presented and discussed accordingly. Results Based on our institutional experience, all three approaches can be utilized to safely and effectively approach a wide variety of neoplastic and vascular pathology. Unique anatomical characteristics, lesion morphology and size, and tumor biology should all be considered when determining the optimal approach. Conclusion Preoperative assessment of surgical corridors with 3D illustrations helps to define the best surgical corridor. 360 degree knowledge of the anatomy of craniovertebral junction allows safe surgical approach and treatment of ventral and ventrolateral located lesions using one of the three approaches.

Approaching Intradural Lesions of the Anterior Foramen Magnum and Craniocervical Junction: Anatomical Comparison of the Open Posterolateral and Anterior Extended Endonasal Endoscopic Approaches.

BACKGROUND: Lesions of the foramen magnum (FM) and craniocervical junction area are traditionally managed surgically through anterior, anterolateral, and posterolateral skull-base approaches. This anatomical study aimed to compare the usefulness of a modified extended endoscopic approach, the so-called far-medial endonasal approach (FMEA), versus the traditional posterolateral far-lateral approach (FLA). METHODS: Ten fixed silicon-injected heads specimens were used in the Skull Base ENT-Neurosurgery Laboratory of the University Hospital of Strasbourg, France. A total of 20 FLAs and 10 FMEAs were realized. A high-resolution computed tomography scan was performed for quantitative analysis of the different approaches. The analysis aimed to estimate the extent of surgical exposure and freedom of movement (maneuverability) through the operating channel using a polygonal surface model to obtain a morphometric estimation of the area of interest (surface and volume) on postdissection computed tomography scans using Slicer 3D software. RESULTS: FMEA allows for a more direct route to the anterior FM, with wider brainstem exposure compared with the FLA and an excellent visualization of all anterior midline structures. The limitations of the FMEA include the deep and narrow surgical corridor and difficulty in reaching lesions located laterally over the jugular foramen and hypoglossal canal. CONCLUSIONS: The FMEA and FLA are both effective surgical routes to reach FM and craniocervical junction lesions. Modern skull base surgeons should have a good command of both because they appear complementary. This anatomical study provides the tools for comprehensive preoperative evaluations and selection of the most appropriate surgical approach.

Far-lateral approach without C1 laminectomy for microsurgical treatment of vertebral artery and proximal posterior inferior cerebellar artery aneurysms: Experience from 48 patients.

Background: In the endovascular era, most of vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms were mainly treated with endovascular procedures. This study aimed to demonstrate the microsurgical treatment via the far-lateral approach without C1 laminectomy and its clinical outcomes. Methods: Forty-eight patients with VA and proximal PICA aneurysms treated by microsurgery through the far-lateral approach without C1 laminectomy, between January 2016 and June 2021, were retrospectively evaluated. Results: Most patients (87.5%) presented with subarachnoid hemorrhage. Grading at presentation was poor in 41.7%. The rates of VA dissecting aneurysms, saccular aneurysms of the VA-PICA junction, and true PICA saccular aneurysms were 54.2, 18.7, and 14.6%, respectively. All aneurysms were located above the lower margin of the foramen magnum. The far-lateral approach without C1 laminectomy was successfully used in all patients without residual aneurysms. Various surgical strategies were applied depending on the characteristics of the aneurysm. Good outcomes 3 months postoperatively were achieved in 77.1% and 89.3% for the overall and good-grade groups, respectively. Conclusions: Microsurgery is a safe and effective treatment of VA and proximal PICA aneurysms. Moreover, the far-lateral approach without C1 laminectomy was adequate and effective for aneurysms located above the lower border of the foramen magnum.

Classification and microsurgical treatment of foramen magnum meningioma.

BACKGROUND: To investigate the classification and microsurgical treatment of foramen magnum meningioma (FMM). METHODS: We retrospectively analyzed 76 patients with FMM and classified them into two classifications, classification ABS according to the relationship between the FMM and the brainstem and classification SIM according to the relationship between the FMM and the vertebral artery (VA). All patients underwent either the far lateral approach (54 cases) or the suboccipital midline approach (22 cases). RESULTS: Of the 76 cases, 47 cases were located ahead of the brainstem (A), 16 cases at the back of the brainstem (B), and 13 cases were located laterally to the brainstem (S). There were 15 cases located superior to the VA (S), 49 cases were inferior (I), and 12 cases were mixed type (M). Among 76 cases, 71 cases were resected with Simpson grade 2 (93.42%), 3 with Simpson grade 3 (3.95%), and 2 with Simpson grade 4 (2.63%). We summarized four anatomical triangles: triangles SOT, VOT, JVV, and TVV. The mean postoperative Karnofsky performance score was improved in all patients (p < 0.05). However, several complications occurred, including hoarseness and CSF leak. CONCLUSION: ABS and SIM classifications are objective indices for choosing the surgical approach and predicting the difficulty of FMMs, and it is of great importance to master the content, position relationship with the tumor, and variable anatomical structures in the four "triangles" for the success of the operation.

Paracondylar process combined with persistent first intersegmental vertebral artery: an anatomic case report and literature review.

The paracondylar process (PCP) and the persistent first intersegmental vertebral artery (PFIA) are both rare variations at the craniovertebral junction. We report the above two variations coexisting in one cadaveric head during the training of far lateral approach in our skull base lab. The specimen simultaneously had a left occipitalized atlas associated with a PFIA and a right PCP. The previous reports, the embryogenesis, and the clinical implications of the two variations were also reviewed. Preoperative recognition of the rare variations is essential to a safe far lateral approach.

A taxonomy for brainstem cavernous malformations: subtypes of medullary lesions.

OBJECTIVE: Medullary cavernous malformations are the least common of the brainstem cavernous malformations (BSCMs), accounting for only 14% of lesions in the authors' surgical experience. In this article, a novel taxonomy for these lesions is proposed based on clinical presentation and anatomical location. METHODS: The taxonomy system was applied to a large 2-surgeon experience over a 30-year period (1990-2019). Of 601 patients who underwent microsurgical resection of BSCMs, 551 were identified who had the clinical and radiological information needed for inclusion. These 551 patients were classified by lesion location: midbrain (151 [27%]), pons (323 [59%]), and medulla (77 [14%]). Medullary lesions were subtyped on the basis of their predominant surface presentation. Neurological outcomes were assessed according to the modified Rankin Scale (mRS), with an mRS score ≤ 2 defined as favorable. RESULTS: Five distinct subtypes were defined for the 77 medullary BSCMs: pyramidal (3 [3.9%]), olivary (35 [46%]), cuneate (24 [31%]), gracile (5 [6.5%]), and trigonal (10 [13%]). Pyramidal lesions are located in the anterior medulla and were associated with hemiparesis and hypoglossal nerve palsy. Olivary lesions are found in the anterolateral medulla and were associated with ataxia. Cuneate lesions are located in the posterolateral medulla and were associated with ipsilateral upper-extremity sensory deficits. Gracile lesions are located outside the fourth ventricle in the posteroinferior medulla and were associated with ipsilateral lower-extremity sensory deficits. Trigonal lesions in the ventricular floor were associated with nausea, vomiting, and diplopia. A single surgical approach was preferred (> 90% of cases) for each medullary subtype: the far lateral approach for pyramidal and olivary lesions, the suboccipital-telovelar approach for cuneate lesions, the suboccipital-transcisterna magna approach for gracile lesions, and the suboccipital-transventricular approach for trigonal lesions. Of these 77 patients for whom follow-up data were available (n = 73), 63 (86%) had favorable outcomes and 67 (92%) had unchanged or improved functional status. CONCLUSIONS: This study confirms that the constellation of neurological signs and symptoms associated with a hemorrhagic medullary BSCM subtype is useful for defining the BSCM clinically according to a neurologically recognizable syndrome at the bedside. The proposed taxonomical classifications may be used to guide the selection of surgical approaches, which may enhance the consistency of clinical communications and help improve patient outcomes.

Immersive Surgical Anatomy of the Far-Lateral Approach.

The far-lateral (FL) approach is a classic neurosurgical technique that enables access to the craniocervical junction, which includes the lower clivus, the anterior foramen magnum, and the first two cervical vertebrae. The FL approach also provides access to the inferior cranial nerves (i.e., CN IX, CN X, CN XI, and CN XII), distal portions of the vertebral artery (VA), and inferior basilar trunk. Recent advances in three-dimensional (3D) technology as well as dissections allow for a better understanding of the spatial relationships between anatomical landmarks and neurovascular structures encountered during neurosurgical procedures. This study aims to create a collection of volumetric models (VMs) obtained from cadaveric dissections that depict the FL approach's relevant anatomy and surgical techniques. We describe the relevant multilayer anatomy involved in the FL approach and discuss modifications of this approach as well. Five embalmed heads and two dry skulls were used to record and simulate the FL approach. Relevant steps and anatomy of the FL approach were recorded using 3D scanning technology (e.g., photogrammetry and structured light scanning) to construct high-resolution VMs. Images and VMs were generated to demonstrate major anatomical landmarks for the FL approach. The interactive models allow for clear visualization of the surgical anatomy and windows in 3D and extended reality, rendering a closer look at the nuances of the topography experienced in the laboratory. VMs can be valuable resources for surgical planning and anatomical education by accurately depicting important landmarks.

Course of the V3 segment of the vertebral artery relative to the suboccipital triangle as an anatomical marker for a safe far lateral approach: A retrospective clinical study.

Background: The third segment of the vertebral artery (V3) is vulnerable during far lateral and retrosigmoid approaches. Although the suboccipital triangle (SOT) is a useful anatomical landmark, the relationship between V3 and the muscles forming the triangle is not well-described. We aimed to demonstrate the relationship between the V3, surrounding muscles, and SOT in clinical cases. Methods: Operative videos of patients with the vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms treated with occipital artery-PICA bypass through the far lateral approach were examined. Videos from January 2015 to October 2021 were retrospectively reviewed to determine anatomy of the V3 and the SOT. Results: Fourteen patients were included in this study. The ipsilateral V3 was identified without injury in all patients using the bipolar cutting technique. The lateral 68.2% of the horizontal V3 segment, including the V3 bulge, was covered by the inferomedial part of the superior oblique muscle (SO). The medial 23.9% was covered by the inferolateral part of the rectus capitis posterior major muscle. The inferomedial part of the horizontal V3 segment is located within the SOT. Conclusion: Most of the V3, including the V3 bulge, were located beneath the SO and the inferomedial part of V3 located within the SOT. Elevation of the SO should be performed carefully using the bipolar cutting technique to avoid injury to the V3. To the best of our knowledge, this is the first description of the V3 relative to the SOT in the clinical setting.

3-Dimensional Exoscope for Far Lateral Approach to Pontomedullary Cavernous Malformation.

Brainstem cavernous malformations account for 15%-18% of all central nervous system cavernomas and are histologically characterized by thin-walled, low-pressure capillaries, classically without intervening brain tissue.1,2 Cavernomas may be sporadic, typically characterized by a single lesion, or inherited. The inherited form is most often autosomal dominant with incomplete penetrance and variable expression. Multiple cavernomas are associated with the familial form; although this is not always the case, genetic workup should be pursued.3,4 Clinical presentation typically includes focal neurologic deficit related to hemorrhage location, seizures, and rarely obstructive hydrocephalus.1,2 Indications for surgical management include severe or progressive neurologic dysfunction, lesion size ≥2 cm, recurring hemorrhages, and/or significant mass effect.5 Microsurgical resection of a cavernoma is associated with an overall 28% complication rate and perioperative neurologic morbidity upwards of 45% according to some series. Long-term surgical outcomes at 12 months are more reassuring: 84% reported their condition to have improved or remained the same, and the long-term morbidity rate is 14%.1,6 The location of the lesion dictates the approaches available-cavernomas in the pons or medulla are commonly approached via a retrosigmoid or retrolabyrinthine approach, while more ventral pathologies in this region necessitate a far lateral approach.1,5,7,8 In Videos 1 and 2, we describe our experience with an exoscope-assisted far lateral approach to a pontomedullary cavernoma in a 10-year-old male presenting with numerous cavernomas and confirmed gene mutation. We demonstrate the exoscope's unparalleled visualization of the anterolateral brainstem, with nominal condylar drilling. The patient and his parents consented to the procedure and publication.

Lateral cervical approach for ventrally located upper cervical meningioma: experience of 14 cases with a narrative comparison with other surgical techniques.

BACKGROUND: Upper cervical meningioma represents a large portion of intradural extramedullary tumors that occur in the cervical spinal canal. Most of them are located ventrally or ventrolateral to the spinal cord. Reaching lesions at this location surgically is technically challenging. OBJECTIVES: The ideal approach to ventrally located upper cervical lesions continues to be controversial. The aim of this study was to discuss the advantage of the lateral cervical approach and compare it with other surgical routes. METHODS: This retrospective study was conducted on all cases of ventrally located upper cervical meningiomas (C1-C3) who have been operated on using the lateral cervical approach in a tertiary neurosurgery unit between 2006 and 2020. Demographic, clinical, surgical, and follow-up data were collected from hospital records. RESULTS: During the study period, fourteen patients (Nine females and five males, aged 42-73 years) were recruited. The follow-up period was 2-16 years. The most frequent presenting symptoms were neck pain, occipital headache, motor deficits, and sensory disturbances. Total excision was achieved in all patients. All patients who had preoperative motor deficits improved significantly postoperatively, and those who presented with sensory disturbance had partial recovery. There was neither mortality nor permanent neurological morbidity. CONCLUSION: A lateral cervical approach is a safe approach for ventrally located upper cervical lesions. In our series, it offered enough exposure for a safe dissection and total or extensive subtotal removal of the tumors. Retraction or rotation of the neuroaxis was avoided, and the incidence of complications (injury of neural or vascular structures, instability, infection) was very low.

Volumetric comparative analysis of anatomy through far-lateral approach: surgical space and exposed tissues.

BACKGROUND: The three-dimensional (3D) visualization model has ability to quantify the surgical anatomy of far-lateral approach. This study was designed to disclose the relationship between surgical space and exposed tissues in the far-lateral approach by the volumetric analysis of 3D model. METHODS: The 3D skull base models were constructed using MRI and CT data of 15 patients (30 sides) with trigeminal neuralgia. Surgical corridors of the far-lateral approach were simulated by triangular pyramids to represent two surgical spaces exposing bony and neurovascular tissues. Volumetric comparison of surgical anatomy was performed using pair t test. RESULTS: The morphometric results were almost the same in the two surgical spaces except the vagus nerve (CN X) exposed only in one corridor, whereas the volumetric comparison represented the statistical significant differences of surgical space and bony and neurovascular tissues involved in the two corridors (P<0.001). The differences of bony and neurovascular tissues failed to equal the difference of surgical space. CONCLUSIONS: For far-lateral approach, the increase of exposure for the bony and neurovascular tissues is not necessarily matched with the increase of surgical space. The volumetric comparative analysis is helpful to provide more detailed anatomical information in the surgical design.

Ovoid Foramen Magnum Shape is Associated with Increased Complications and Decreased Extent of Resection for Anterolateral Foramen Magnum Meningiomas.

Background Antero-laterally located meningiomas of the foramen magnum (FM) pose significant surgical resection challenges. The effect of FM shape on surgical resection of FM meningiomas has not been previously studied. The present study investigates how FM shape effects the extent of tumor resection and complication rates in antero-lateral FM meningiomas. Materials and Methods This retrospective study included 16 consecutive patients with antero-lateral FM meningiomas operated on by a single surgeon. FMs were classified as ovoid ( n = 8) and nonovoid ( n = 8) using radiographic evaluation. Results Sixteen patients were examined: seven males and nine females (mean age of 58.5, and range of 29 to 81 years). Gross total resection was achieved in 81% of patients, with tumor encased vertebral arteries in 44%. Patient characteristics were similar including age, sex, preoperative tumor volume, relationship of vertebral artery with tumor, preoperative Karnofsky performance score (KPS), symptom duration, and presence of lower cranial nerve symptoms. The ovoid FM group had lower volumetric extents of resection without statistical significance (93 ± 10 vs. 100 ± 0%, p = 0.069), more intraoperative blood loss (319 ± 75 vs. 219 ± 75 mL, p = 0.019), more complications per patient (1.9 ± 1.8 vs. 0.3 ± 0.4, p = 0.039), and poorer postoperative KPS (80 ± 21 vs. 96 ± 5, p = 0.007). Hypoglossal nerve palsy was more frequent in the ovoid FM group (38 vs. 13%). Conclusion This is the first study demonstrating that ovoid FMs may pose surgical challenges, poorer operative outcomes, and lower rates of extent of resection. Preoperative radiological investigation including morphometric FM measurement to determine if FMs are ovoid or nonovoid can improve surgical planning and complication avoidance.

The Far-Lateral Suboccipital Approach to the Lesions of the Craniovertebral Junction.

The far-lateral suboccipital approach and its variants, including the transcondylar, supracondylar, and paracondylar approaches, are essential skull base techniques for the neurosurgeon to expose and treat pathologies located at the ventral and ventrolateral craniovertebral junction. An understanding of the surgical anatomy and technical nuances of these approaches is vital for preventing catastrophic brainstem or spinal cord injury, neurovascular injury, and/or cranial nerve injury. This is achieved by carefully studying the location, the rostral-caudal and lateral extents of the lesion itself, and the anatomy of the surrounding structures on preoperative imaging. The amount of bony exposure should be tailored to each specific lesion to avoid unnecessary bone drilling and therefore decrease the risk of potential craniocervical instability. Minimizing retraction of the cerebellum, brainstem, and spinal cord is important for preventing neurologic injury; therefore, appropriate intraoperative head positioning and adequate bony exposure should be ensured, especially for more ventrally located lesions. A thorough knowledge of the anatomy of the extradural and intradural segments of the vertebral artery, and the lower cranial nerves, in relation to the lesion is also critical. For almost all lesions, the far-lateral suboccipital route with no or minimal condylar drilling is more than adequate for removing the most ventral lesions. Herein, we discuss the indications, general and preoperative considerations, and surgical anatomy and technical nuances of this approach.

Endoscope-Assisted Resection of Extra-Axial Premedullary Neurenteric Cyst via Far Lateral-Supracondylar Approach: 2-Dimensional Operative Video.

Neurenteric cysts are rare congenital lesions that may compress the ventral brainstem.1-9 In this operative video, we illustrate the surgical treatment of an intradural extra-axial neurenteric cyst extending from the lower pons to the craniocervical junction. The patient, an asymptomatic 52-yr-old female, underwent surveillance imaging of the premedullary lesion for 14 yr without progression. However, after developing progressive strain-induced headaches, imaging revealed a significant enlargement of the lesion with brainstem compression and partial obstruction of the foramen magnum. Therefore, surgical resection was pursued. The patient consented to the procedure. The patient underwent a lateral suboccipital craniotomy and C1 laminectomy through a far lateral approach. The lesion was immediately visualized upon opening the dura. After identifying the cranial nerves, we resected the tumor while taking care to preserve the neurovascular elements of the cerebellopontine angle and foramen magnum. During the resection, we unexpectedly encountered a firm nodule that was adherent to the right posterior inferior cerebellar artery. This was meticulously dissected and removed en bloc using intraoperative indocyanine green (ICG) angiography. The cavity was inspected with 0-degree and 30-degree endoscopes to ensure complete resection of the lesion. Gross total resection was confirmed on postoperative magnetic resonance imaging. The patient was neurologically intact with no cranial nerve abnormalities and discharged home on postoperative day 3. This case demonstrates that the far lateral-supracondylar approach affords safe access to the ventral pontomedullary and craniocervical junctions and that intraoperative adjuncts, including ICG angiography and endoscopic visualization, can facilitate complete lesion resection with excellent clinical outcomes.