UNASSIGNED: To review our single-institution experience in the surgical management of foramen magnum tumors via a far-lateral approach using an oblique straight incision.
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.

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.
METHODS: 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.
CONCLUSIONS: Dumbbell-shaped C1 schwannomas can be safely removed by using the far lateral approach, surgical anatomy expertise, and intraoperative microvascular Doppler.

To provide further information on the identification of the occipital artery (OA) and suggest an improved approach to its anterograde dissection technique for harvesting.
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.
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.
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.

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.
CONCLUSIONS: 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.

BACKGROUND: Anti-tuberculous therapy (ATT) alone cannot easily cure spine tuberculosis (STB) though it is the most essential treatment. Many studies have confirmed the efficacy of the surgical treatment of STB through anterior, anterolateral, posterior debridement, and intervertebral fusion or combined with internal fixation. However, the conventional surgical approach requires extensive exposure of the affected areas with high rates of morbidity and mortality. Recently, minimally invasive surgery has come into use to reduce iatrogenic trauma and relevant complications. Here, we introduced a novel technique for the treatment of thoracic and lumbar spine tuberculosis: minimally invasive far lateral debridement and posterior instrumentation (MI-FLDPI). In this study, we evaluated the technical feasibility, the clinical outcomes, and the postoperative complications.
METHODS: We did a prospective, non-randomized study on this new technique. Twenty three patients (13 males) with thoracic or lumbar spine tuberculosis who underwent minimally invasive far lateral debridement and posterior instrumentation were included in the study. The preoperative comorbidities, operation duration, intra-operative hemorrhage, Cobb\'s angles, and postoperative complications were recorded and analyzed. Clinical outcomes were evaluated by Visual Analog Scale (VAS), Oswestry Disability Index (ODI), neurological recovery, and eradication of tuberculosis. Radiological outcomes were evaluated by changes in Cobb\'s angle and fusion status of the affected segments.
RESULTS: The patients were followed for an average of 19 months (ranging from 12 to 36 months). At the final follow-up, CRP and ESR of all patients were normal. The VAS and ODI were significantly improved compared with preoperative values (P < 0.05). No evident progression of the kyphotic deformity was found after surgery. Twenty two patients showed spontaneous peripheral interbody fusion 1 year after surgery. There were no failure of the instrumentation even though a young female with drug-resistant tuberculosis showed no sign of interbody fusion at the third year follow-up. All the patients with preoperative neurological deficit showed complete recovery at the final follow-up.
CONCLUSIONS: MI-FLDPI using expandable tubular retractor could be recommended to treat thoracic and lumbar spine tuberculosis for the advantages of less trauma, earlier recovery, and less complications. Spontaneous peripheral interbody fusion was observed in nearly all the cases even without bone grafting.

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.

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 .

OBJECTIVE: The far-lateral approach (FLA) remains a challenge for neurosurgeons due to the complex anatomy of this region, especially in patients with anatomical variations. There is therefore an urgent need for better quantitative knowledge of the microsurgical anatomy of the FLA.
METHODS: The study was performed using the dried skulls and atlas vertebrae of 50 Chinese adults, in which significant clinical parameters were measured. We further used 12 cadaveric heads to simulate the FLA to explore the step-by-step anatomy entailed by this procedure, enabling us to obtain key images and related information.
RESULTS: Limited to hypoglossal canal, the occipital condyle posterior was abraded by roughly 10 mm, which provided good exposure to the ventral front of the foramen magnum. When occipital artery exits the occipital groove, the mean diameter was 2.20 mm. The average occipital artery suboccipital segment length was 65.26 mm. The posterior spinal artery (PSA) and posterior inferior cerebellar artery (PICA) generally originated from the fourth vertebral artery segment intradurally, and the mean distances from the PSA and PICA to the dural entry point of the vertebral artery were 2.62 mm and 8.71 mm, respectively. The incidence of PSA and PICA arising from the third vertebral artery segment was 16.67% and 4.17%, respectively.
CONCLUSIONS: Understanding the important anatomic structures of the CVJ region and developing improved knowledge of the microsurgical anatomy of the FLA offer an opportunity to ensure safe exposure and treatment of lesions in the ventral and ventrolateral regions of the CVJ.

Posterior circulation ischemic strokes can have devastating consequences, despite medical therapies. Extracranial-intracranial bypass for the augmentation of flow is a treatment option for selected patients with hemodynamic compromise and recurrent ischemia. However, posterior circulation bypass carries a higher risk and lower patency rate than bypass with anterior circulation.
To present the occipital artery to the extradural vertebral artery (OA-eVA) bypass for posterior circulation ischemia.
We retrospectively reviewed our experience of the OA-eVA bypass surgery in the treatment of bilateral vertebral steno-occlusive disease.
Seventeen patients were identified. Thirteen patients had bilateral vertebral artery (VA) occlusion (type I), while 4 patients had VA occlusion with contralateral VA severe stenosis (type II). All patients had cerebellar or pons infarction, for which the postoperative bypass patency rate was 100%, with carotid angiogram demonstrating excellent filling of the rostral basilar system or the posterior inferior cerebellar artery territory. The long-term follow-up outcome was favorable (modified Rankin score of 0-2) in 82% of patients (7 patients had complete resolution and 7 had improvement of symptoms) and unfavorable in 18%. One type II case without previous endovascular therapy developed recurrent ischemic onset associated with bypass occlusion.
OA-eVA bypass is a minimally invasive and effective alternative to posterior circulation ischemia. It provides sufficient blood flow augmentation to the vertebrobasilar territory. The advantages of this novel therapeutic strategy include avoiding performing craniotomy and deep bypass and achieving shorter operative times compared to conventional bypass surgery.

Several far lateral approaches have been proposed to deal with cranio-vertebral junction (CVJ) tumors including the basic, transcondylar, and supracondylar far lateral approaches (B-FLA, T-FLA, and S-FLA). However, the indications on when to use one versus the other are not well systematized yet. Our purpose is to evaluate in an experimental cadaveric setting which approach is best suited to remove tumors of different sizes.
We implanted at the CVJ, using a transoral approach, tumor models of different sizes (five 1-cm3 and five 3-cm3 tumors) in ten embalmed cadaveric heads. The artificial tumors were exposed via the three approaches using endoscopic-assisted microneurosurgical technique and neuronavigation. The skull base area exposed and the maneuverability linked to each approach were evaluated using neuronavigation.
In 1-cm3 tumors, the T-FLA and the S-FLA exposed a significantly larger skull base area than the B-FLA both using the microscope and the endoscope (P < 0.05); the T-FLA executed with the microscope provided wider vertical and horizontal maneuverability than the B-FLA (P = 0.030 and 0.017, respectively); the S-FLA executed with the endoscope provided wider vertical maneuverability than the T-FLA (P = 0.031). The S-FLA executed using the microscope and the endoscope provided wider vertical maneuverability than the B-FLA both in 1 and 3-cm3 tumors (P < 0.05).
In 1-cm3 tumors, the S-FLA and the T-FLA expose a wider skull base area than the B-FLA. In larger tumors, the exposure is similar for all three approaches. Use of the endoscope in an assistive mode may further increase the surgical exposure and maneuverability.