Eosinophilic meningitis following suboccipital craniotomy without bovine dural graft: illustrative case

BACKGROUND Eosinophilic meningitis is a rare known complication after brain surgery associated with duraplasty using artificial bovine graft. However, eosinophilic meningitis after craniotomy without bovine dural graft has not been reported. OBSERVATIONS A 48-year-old female presented with lateral medullary infarction caused by a vertebral artery dissecting aneurysm incorporating the posterior inferior cerebellar artery (PICA). The authors performed occipital artery–PICA anastomosis and repaired the dura by primary suture without bovine graft. Thereafter, endovascular internal trapping using coils was conducted. Severe headache developed at postoperative day 17, and the patient was diagnosed with eosinophilic meningitis. After administration of a high-dose corticosteroid for 2 weeks, her symptoms and laboratory findings were improved. LESSONS Postoperative eosinophilic meningitis is rarely related to craniotomy without using bovine graft. Neurosurgeons should consider the possibility of eosinophilic meningitis after craniotomy without a xenogeneic dural material.

Late recurrence of primary cerebellar germinoma at unusual site after complete response to radiotherapy

Background: The primary cerebellar germinoma is exceptional and difficult to diagnose preoperatively. Its recurrence at the middle cranial fossa after complete response to radiotherapy is unique and associated with a poor prognosis. This article aims to report the successful management of the late recurrence of primary cerebellar germinoma at an unusual site after 4 years of complete response to radiotherapy. Case Description: A 22-year-old male was admitted to our hospital with complaints of severe headache and loss of balance. Brain magnetic resonance imaging (MRI) showed a triventricular hydrocephalus due to a 45x50mm cerebellar mass. Our preliminary diagnosis was medulloblastoma. First, we placed a ventriculoperitoneal shunt with the medium-pressure valve, and then we used midline suboccipital craniotomy to remove the tumor completely. The histopathology was germinoma. The patient received 24 Gy craniospinal irradiation (CSI) with a 16 Gy boost to the primary site and had an MRI follow-up every six months. After a 4-year follow-up, he complained of recurrent severe headaches. The brain MRI illustrated a 62 × 61 mm temporal mass. We extirpated this tumor, and histopathology again revealed germinoma. After that, the patient received induction radiotherapy. The 1-year postoperative MRI showed no tumor remnant. At the time of writing, the patient had no headache and no neurological deficits. Conclusion: Regular follow-ups with routine neuroaxis MRI should be recommended to detect recurrence early for all patients with intracranial germinomas. Surgical resection, if possible, and subsequent CSI are the most effective salvage treatment for recurrent germinoma.

Presentation, diagnosis, and treatment of a cerebellar tuberculoma: illustrative case

BACKGROUND Central nervous system (CNS) tuberculomas are a feared complication of tuberculosis (TB) infection. These lesions can present in varying manners and are associated with significant morbidity and mortality. Prompt diagnosis and treatment of the lesion and the underlying infection are critical in the care of these patients. The authors presented a case of a 45-year-old Yemeni immigrant presenting with a 3-month history of severe right temporo-occipital headaches with photophobia and night sweats. Imaging showed a rim-enhancing lesion in the right cerebellar hemisphere. OBSERVATIONS Laboratory tests were unremarkable and within normal limits. QuantiFERON testing was negative, ruling out latent TB infection. The patient received a suboccipital craniotomy, and resection of the cerebellar lesion showed caseating granuloma formation, which was positive for acid-fast bacilli and Fite stain. LESSONS CNS tuberculomas are an important differential to consider in patients with a history of primary TB, regardless of active disease or immunocompetent status. Resection of these lesions remains a viable treatment option that is safe and effective.

Microsurgical Resection of Dorsal Pontine Cavernous Malformation: The Telovelar Approach Augmented by the Tonsillouvular Fissure Exposure: 2-Dimensional Operative Video

Surgical approaches to lesions of the fourth ventricle (FV) have been modified over the years to reduce the complications associated with splitting the inferior cerebellar vermis (ICV) and disrupting the brainstem and critical surrounding structures.1-4 Two common approaches to lesions of this region include the transvermian approach (TVA) and telovelar approach (TeVA).2 The TVA was initially considered the conventional route of access to lesions of the FV1 but has been associated with significant risks, including possible gait ataxia and dysarthria.3 The TeVA is advantageous, as it involves dissection along natural clefts and division of non-neural tissue and provides good exposure of the superolateral recess with modest exposure of the rostral FV. The TeVA approach can be augmented by opening the tonsilouvular fissures (TUFs). This added dissection allows greater lateral and superior exposure with less need for retraction. In this operative video, we demonstrate a case in which we augmented the TeVA with a TUF dissection to access a dorsal pontine cavernous malformation. We performed a midline suboccipital craniotomy with a C1 posterior laminectomy. TUF dissection was followed by division of the tela choroidea (TC), which allowed for more lateral exposure of the FV and excellent visualization of the cavernous malformation without the need to traverse neural tissue. TeVA augmented by TUF dissection provided adequate access to the dorsal pons for complete resection of the cavernous malformation. The patient consented to the procedure as shown in this operative video and gave informed written consent for use of her images in publication. Anatomic images provided by courtesy of © The Rhoton Collection. http://rhoton.ineurodb.org/. Video © Mayo Foundation for Medical Education and Research, 2021. Used with permission.

Resection of a Medulla Oblongata Hemangioblastoma: 2-Dimensional Operative Video

Hemangioblastomas are benign vascular tumors that can be sporadic or multiple, as part of Von Hippel-Lindau disease. They develop at any level of the central nervous system, with a predilection for the dorsal medulla among brainstem locations. Radical resection of the solid portion of the tumor is the best treatment option.1,2 The resection should be en bloc to avoid uncontrollable intraoperative hemorrhage hindering safe dissection. Preservation of the venous drainage during the progressive dissection of the tumor of the surrounding structures and interruption of numerous small arterial feeders is a tenet for safe surgical resection.3 Once the tumor is completely disconnected, the large draining veins can be coagulated, and the tumor removed. We demonstrate these technical principles in the surgery of a 30-yr-old female with an exophytic hemangioblastoma from the dorsal medulla obstructing the fourth ventricle outflow. We demonstrate the resection of this lesion through a suboccipital craniotomy in a sitting position.4 The patient consented to the surgery and publication of images. Image at 1:26 from Kadri and Al-Mefty,4 by permission from the Congress of Neurological Surgeons.

Management of a Persistent Oblique Occipital Sinus with Staged Ligation in a Case of Medulloblastoma: A Case Report

<b><i>Introduction:</i></b> A patent persistent occipital sinus (OS) can be seen in 10% of adults. The presence of such a dominant draining OS can present as a challenge for posterior fossa surgeries. Occlusion or division of the sinus can cause venous hypertension, causing a cerebellar bulge or increased intra-op bleeding. <b><i>Case report:</i></b> A 3-and-a-half-year-old female child presented with a vermian medulloblastoma with hydrocephalus. MR venography (MRV) revealed a large patent OS draining from the torcula to the right sigmoid sinus. She underwent a left Frazier’s point VP shunt followed by a midline suboccipital craniotomy for the lesion. The OS was divided during a “Y”-shaped durotomy. Following the sinus ligation, there was a significant cerebellar bulge and excessive bleeding from the lesion. We released cisternal CSF and punctured the tumor cysts to allow the brain bulge to settle. Hemostasis was secured, and surgery was deferred, an augmented duroplasty was done, and bone flap was removed to allow for intracranial pressure decompression. The patient was electively ventilated for 24 h and weaned off gradually. A repeat MRV at 7 days showed the reorganization of the venous outflow at the torcula. Reexploration with tumor resection was done on post-op day 10. The patient recovered well from the surgery and was referred for adjuvant therapy. <b><i>Conclusion:</i></b> Surgeons should carefully analyze venous anatomy before posterior fossa surgeries. The persistent dominant OS, when present, should be taken care of while planning the durotomy. A hypoplastic but persistent transverse sinus allowed us to ligate and divide the OS. By doing a staged division of the sinus, reorganization of the venous outflow from the torcula can be allowed to occur, and the lesion can be resected.

Lateral Suboccipital Craniotomy With C1-C2 Hemilaminectomies and C1-C3 Fusion for the Treatment of a C1-C2 Synovial Cyst Causing Spinal Cord Compression: 2-Dimensional Operative Video

Atlantoaxial synovial cysts are a rare cause of cervical myelopathy. Here we describe a case of a 26-yr-old woman who presented with progressively decreasing right arm and leg strength and associated gait imbalance. On examination, she had diffuse weakness in the right upper and lower extremities, a positive right-sided Hoffman sign, and clonus in the right lower extremity. Computed tomography demonstrated an os odontoideum and a retro-odontoid cyst. Magnetic resonance imaging demonstrated a T1 hypointense, T2 hyperintense, slightly rim-enhancing retro-odontoid cyst causing a marked narrowing of the spinal canal, with resultant flattening and leftward deviation of the spinal cord. The patient consented to undergo cyst fenestration via a right suboccipital craniotomy and right C1-C2 hemilaminectomies, along with a C1-C3 instrumented posterior spinal fusion. This approach was chosen because it allows for cyst fenestration and instrumentation of the hypermobile cervical spine within the same incision. After the dura was opened and the arachnoid was dissected, the cyst was visualized compressing the spinal cord. The cyst was fenestrated just inferior to the C1 nerve rootlets, resulting in immediate egress of a gelatinous content; thereafter, all accessible cyst wall portions were removed. Fusion was performed with lateral mass screws at C1 and C3 and pars screws at C2. Pathological analysis described the cyst content as reactive fibrovascular tissue with cholesterol deposition. There were no complications associated with the procedure, and the patient's right-sided weakness had nearly resolved by postoperative day 1. Patient consent was granted for publication.

Infratentorial abscess secondary to dermal sinus associated with dermoid cyst in children: Review of the literature and report of a rare case

Background: Dermal sinus is usually located at either end of neural tube but most commonly lumbosacral. When occipital, it extends caudally and is mostly localized in the midline position or in the cavity of the fourth ventricle. It could communicate with the skin through a fistula with potential risk of deeper abscesses. Posterior fossa abscess secondary to dermal sinus associated with intracranial dermal cyst is an uncommon pathology. Case Description: A 24-month-old girl was admitted to our institution with a cutaneous fistula in the midline of the occipital region. Brain imaging showed an infratentorial intradiploic cyst with peripheral enhancement to contrast medium. The mass showed hyperintensity on T1-weighted sequences, with the lower signal on T2-weighted images. A suboccipital craniotomy was performed with evacuation of the abscess and excision of the capsule. Contextually a 3 cm whitish and encapsulated cystic mass with hair component was extracted. Histology confirmed the diagnosis of abscess associated with dermal cyst and dermal sinus. The patient condition improved and 15 days after excision, was discharged. The postoperative MRI showed total removal of the lesion. A 36-month follow-up highlighted no evidence of recurrence. Conclusion: Posterior fossa dermoid cyst should be considered in all children with a cutaneous fistula. Early neurosurgical treatment of these benign tumors should be performed to prevent the development of severe intracranial infection. Best results are associated with early diagnosis and complete removal of the abscess. The present work further reviews the few similar cases that have been reported in the literature confirming the need for future research.

Endoscopic-Assisted Resection of Anterior Foramen Magnum Meningiomas through a Midline Suboccipital Subtonsillar Approach

Objective This study was aimed to demonstrate the resection of anterior foramen magnum meningiomas through an endoscopic-assisted posterior midline suboccipital subtonsillar approach. Design This study was designed with illustration of the surgical steps and safety of this approach. Setting Evidence of cerebrospinal fluid (CSF) cleft between the tumor and brainstem on MRI was studied (Fig. 1A and B). Preoperative tracheotomy was considered in cases of preoperative dysphagia to prevent any further neurological deterioration due to the bilateral access through the lower cranial nerves corridors. Semisitting position with extensive electrophysiological neuromonitoring and transesophageal echocardiogram was adopted. A standard midline incision with bilateral suboccipital craniotomy and C1-laminotomy was performed (Fig. 2A). After partial resection and elevation of the tonsils, tumor was debulked unilaterally around the lower cranial nerves and the vertebral artery, devascularized from the clival dura and then dissected from the brainstem (Fig. 2B, C). Endoscopic-assisted removal of its anterior portion followed. The same procedure was repeated from the opposite site for the contralateral portion, before approaching the purely anterior part with endoscope assistance (Fig. 2D). Participants Four consecutive patients were included in the study. Main Outcome Measures Grade of tumor resection and outcome (mRS) were primary measurement of this study. Results Clinical outcome and grade of resection are comparable to other series of patient treated with other foramen magnum approaches (Fig. 1C and D). Conclusion Anterior foramen magnum meningiomas can be safely removed through this relatively faster midline suboccipital approach with bilateral exposure of lower cranial nerves (CNs) and vertebral arteries and lower approach-related morbidity (no condyle drilling). The surgical corridor is created by the tumor during debulking reducing need for brain retraction and the removal of the anterior dural attachment coagulated under the microscope is verified and completed endoscopically with pituitary curettes (Simpson's grade II) (Fig. 1C and D).The link to the video can be found at: https://youtu.be/9eACAJVwQBs.