Orthostatic hypotension after cervicomedullary junction surgery: illustrative case

BACKGROUND Surgery at the cervicomedullary junction carries a risk of damaging vital brainstem functions. Because the nucleus of the solitary tract (NS) is involved in the baroreceptor reflex, damage to its integrity may lead to orthostatic hypotension. OBSERVATIONS A 56-year-old man with a medical history of hypertension, von Hippel-Lindau disease, and previous bilateral adrenalectomy due to pheochromocytoma was referred with symptoms of dysphagia and paralysis of the left vocal cord. Paralysis of the left vagus nerve was suspected. Magnetic resonance imaging revealed a contrast-enhancing cystic process in the cervicomedullary junction. Twenty-three years earlier, the patient had undergone surgical treatment for a hemangioblastoma in the same region. After repeated surgery, the patient temporarily developed orthostatic hypotension. At discharge, the patient no longer needed antihypertensive medication. LESSONS Surgery near the cervicomedullary junction can affect the NS, leading to disruption of the baroreceptor response that regulates blood pressure.

Foramen Magnum Stenosis in Achondroplasia

Achondroplasia is the most common hereditary skeletal dysplasia and is characterized by disproportionately short stature with rhizomelic short extremities [1]. The skull features include a narrowed foramen magnum, short skull base, and clivus [2]. Foramen magnum stenosis is a characteristic funding, secondary to an abnormal placement and premature fusion of the posterior synchondroses [1]. The second factor responsible for stenosis is a defect in endochondral ossification in the basiocciput that may result in an extension of the squamous occipital bone [2]. It can cause hydrocephalus and prominent emissary and meningeal veins (Figure 1). Figure 1: Sagittal T1WI revealing a narrowed stenosis of the foramen magnum and compression of the cervicomedullary junction. The most severe complication is the compression of the cervicomedullary junction, associated with severe morbidity and sudden death in younger children [1].

Outcome Features Analysis in Intramedullary Tumors of the Cervicomedullary Junction: A Surgical Series

Object The aim of this study is to investigate the impact of surgery for different cervicomedullary lesions on symptomatic pattern expression and postoperative outcome. We focused on specific outcome features of the early and late postoperative assessments. The former relies on surgery-related transient and permanent morbidity and feasibility of radicality in eloquent areas, whereas the latter on long-term course in lower grade tumors and benign tumorlike lesions (cavernomas, etc.). Material and Methods We retrospectively analyzed 28 cases of intramedullary tumors of the cervicomedullary junction surgically treated at our institution between 1990 and 2018. All cases were stratified for gender, histology, macroscopic appearance, location, surgical approach, and presence of a plane of dissection (POD). Mean follow-up was 5.6 years and it was performed via periodic magnetic resonance imaging (MRI) and functional assessments (Karnofsky Performance Scale [KPS] and modified McCormick [MC] grading system). Results In all, 78.5% were low-grade tumors (or benign lesions) and 21.5% were high-grade tumors. Sixty-one percent underwent median suboccipital approach, 18% a posterolateral approach, and 21% a posterior cervical approach. Gross total resection was achieved in 54% of cases, near-total resection (>90%) in 14%, and subtotal resection (50–90%) in 32% of cases. Early postoperative morbidity was 25%, but late functional evaluation in 79% of the patients showed KPS > 70 and MC grade I; only 21% of cases showed KPS < 70 and MC grades II and III at late follow-up. Mean overall survival was 7 years in low-grade tumors or cavernomas and 11.7 months in high-grade tumors. Progression-free survival at the end of follow-up was 71% (evaluated mainly on low-grade tumors). Conclusions The surgical goal should be to achieve maximal cytoreduction and minimal postoperative neurologic damage. Functional outcome is influenced by the presence of a POD, radicality, histology, preoperative status, and employment of advanced neuroimaging planning and intraoperative monitoring.

Endoscopic Endonasal Transclival Odontoidectomy for Basilar Invagination: Operative Video and Technical Nuances

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.

Far-Lateral Transcondylar Approach to a Right Cervicomedullary Dural Arteriovenous Fistula of the Posterior Fossa

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.

Pediatric ganglioglioma of the brainstem and cervicomedullary junction: a retrospective cohort study

OBJECTIVEGanglioglioma is a low-grade central nervous system neoplasm with a pediatric predominance, accounting for 10% of all brain tumors in children. Gangliogliomas of the cervicomedullary junction (GGCMJs) and brainstem (GGBSs) present a host of management challenges, including a significant risk of surgical morbidity. At present, understanding of the prognostic factors—including BRAF V600E status—is incomplete. Here, the authors report a single-institution GGCMJ and GGBS experience and review the pertinent literature.METHODSA prospectively maintained neurosurgical database at a large tertiary care academic referral center was retrospectively queried for cases of GGCMJ pathologically confirmed in the period from 1995 to 2015; appropriate cases were defined by diagnosis codes and keywords. Secondary supplemental chart review was conducted to confirm or capture relevant data. The primary study outcome was treatment failure as defined by evidence of radiographic recurrence or progression and/or clinical or functional decline. A review of the literature was conducted as well.RESULTSFive neurosurgically managed GGBS patients were identified, and the neoplasms in 4 were classified as GGCMJ. All 5 patients were younger than 18 years old (median 15 years, range 4–16 years) and 3 (60%) were female. One patient underwent gross-total resection, 2 underwent aggressive subtotal resection (STR), and 2 underwent stereotactic biopsy only. All patients who had undergone STR or biopsy required repeat resection for tumor control or progression. Progressive disease was treated with radiotherapy in 2 patients, chemotherapy in 2, and chemoradiotherapy alone in 1. Immunostaining for BRAF V600E was positive in 3 patients (60%). All 5 patients experienced at least one major complication, including wound infection, foot drop, hemiparesis, quadriparesis, cranial neuropathy, C2–3 subluxation, syringomyelia, hydrocephalus, aspiration, and coma. Overall mortality was 20%, with 1 death observed over 11 years of follow-up.CONCLUSIONSGGBS and GGCMJ are rare, benign posterior fossa tumors that carry significant perioperative morbidity. Contemporary management strategies are heterogeneous and include combinations of resection, radiotherapy, and chemotherapy. The BRAF V600E mutation is frequently observed in GGBS and GGCMJ and appears to have both prognostic and therapeutic significance with targeted biological agents.