Intradural Component Research Articles

Concurrent spinal nerve root schwannoma and meningioma mimicking single‐component schwannoma

We present a first case of concurrent tumors consisting of schwannoma and meningioma arising at the same spinal level in a patient without neurofibromatosis. A 49-year-old man without clinical evidence of neurofibromatosis presented with a 5-month history of right neck pain. MRI demonstrated an extradural tumor involving the right-sided C2 nerve root with a small intradural component. T1- and T2-weighted and contrast-enhanced MRI could not differentiate the intradural tumor as different from the extradural tumor. Total removal of the tumors was performed. No contiguity of the extradural tumor with the intradural tumor was seen. The intradural tumor attached strongly to the dura mater around the C2 nerve root exits. Intraoperative pathological diagnosis confirmed the extradural tumor as schwannoma and the intradural tumor as meningioma. We therefore thoroughly coagulated the dura mater adjacent to the intradural tumor and resected the dura mater around the nerve root exits together with the tumor. Pathological examination revealed that the resection edge of the extradural component consisted of a spinal nerve with thickened epineurium and was free of neoplastic cells. No schwannoma component was evident in the intradural tumor. No obvious transition thus existed between the extra- and intradural tumors. Distinguishing these tumors prior to surgery is critical for determining an optimal surgical plan, as schwannoma and meningioma require different surgical procedures. We therefore recommend a careful review of preoperative imaging with the possibility of concurrent tumors in mind.

Management of complex tympanojugular paragangliomas including endovascular intervention

To identify complex cases of tympanojugular paraganglioma (TJP) and to analyze their management and surgical outcome. To present strategy and guidelines on how to deal with the perioperative complicating factors. Retrospective analysis. We retrospectively studied 212 TJP patients to identify the complex cases and analyzed their management and surgical outcome. The criteria for complex TJP are: 1) very large size; 2) large intradural extension (IDE); 3) extension to the cavernous sinus, foramen magnum, and clivus; 4) significant involvement of the internal carotid artery (ICA); 5) a solitary ICA on the lesion side; 6) involvement of the vertebral artery; 7) dominant or unilateral sigmoid sinus on the lesion side; 8) bilateral or multiple paragangliomas; and 9) recurrence. Sixty patients were classified as complex. Forty-five patients had tumors with IDE. Twenty patients with tumor involving ICA underwent preoperative endovascular intervention. Two patients had a solitary ICA and two others unilateral sigmoid sinus on the lesion side. Thirteen patients had multicentric tumors, and three patients had bilateral ones. The main procedure was the infratemporal fossa approach type A. Total removal was achieved in 46 patients, and five of them experienced recurrence. It is essential to carefully investigate the hemodynamics of the brain in planning surgery. A proper preoperative endovascular intervention facilitates gross total tumor removal. In bilateral paragangliomas, lower cranial nerves' function should be preserved at least unilaterally. Staged removal is recommended for a tumor with a large intradural component.

Editorial: Gamma Knife and meningiomas

Editorial: Gamma Knife and meningiomas

Endoscopic Endonasal Anatomy and Approaches to the Anterior Skull Base

The objective of this study was to review the endoscopic anatomy of the anterior skull base, defining the pitfalls of endoscopic endonasal approaches to this region. Recently, these approaches are gaining popularity among neurosurgeons, and the details of the endoscopic anatomy and approaches are highlighted from the neurosurgeons' point of view, correlated with demonstrative cases. Twelve fresh adult cadavers were studied (n = 12). We used Karl Storz 0 and 30 degrees, 4 mm, 18- and 30-cm rod lens rigid endoscope in our dissections. After preparation of the cadaveric specimens, we approached the anterior skull base by the extended endoscopic endonasal approach. After resection of the superior portion of the nasal septum, bilateral middle and superior turbinates, and bilateral anterior and posterior ethmoidal cells, we could obtain full exposure of the anterior skull base. The distance between optic canal and the posterior ethmoidal artery ranged from 8 to 16 mm (mean, 11.08 mm), and the distance between posterior ethmoidal artery and the anterior ethmoidal artery ranged from 10 to 17 mm (mean, 13 mm). After resecting the anterior skull base bony structure and the dura between the 2 medial orbital walls, we could visualize the olfactory nerves, interhemispheric sulcus, and gyri recti. With dissecting the interhemispheric sulcus, we could expose the first (A1) and second (A2) segments of the anterior cerebral artery, anterior communicating artery, and Heubner arteries. This study showed that extended endoscopic endonasal approaches are sufficient in providing wide exposure of the bony structures, and the extradural and intradural components of the anterior skull base and the neighboring structures providing more controlled manipulation of pathologic lesions. These approaches need specific skill and learning curve to achieve more minimally invasive interventions and less postoperative complications.

Intradural Involvement of Multicentric Myxoid Liposarcoma

Liposarcomas are malignant tumors of the soft tissue, with myxoid liposarcoma being the second most common subtype, tending to occur in the limbs, particularly in the thighs. Myxoid liposarcomas have an intermediate prognosis between well-differentiated and pleomorphic tumors. Spinal metastasis is usual but intradural involvement is extremely rare. We present an unusual case of a multicentric myxoid liposarcoma with intradural involvement. A 41-year-old woman complained of tingling sensation on her left arm. Radiological evaluation revealed multiple masses in her cervical spine, abdominal wall, liver, heart and right thigh, all of which were resected. She was histologically diagnosed with small round cell myxoid sarcoma and underwent adjuvant chemotherapy. However, magnetic resonance imaging analysis after 1 year revealed a large metastatic mass with bony invasion at the C6-T1 level. This mass consisted of extradural and intradural components causing severe compression of the spinal cord. She underwent resection via a posterior facetectomy of C6-7 and an anterior C7 corpectomy. However, the patient died of multiple metastases 18 months after the first diagnosis.

Surgical Management of Jugular Foramen Meningiomas: A Series of 13 Cases and Review of the Literature

Primary meningiomas occurring within the jugular foramen are exceedingly rare lesions presumed to originate from arachnoid-lining cells situated within the jugular foramen. The objective of this study is to analyze the management and outcome in a series of 13 primary jugular foramen meningiomas collected at a single center. Retrospective study. Quaternary referral otology and skull base private center. Charts belonging to 13 consecutive patients with pathologically confirmed jugular foramen meningioma surgically treated between September 1991 and May 2005 were examined retrospectively. The follow-up of the series ranged from 12 to 120 (mean, 42.8 +/- 27.5) months. Four (28.5%) patients underwent single-stage tumor removal through the petro-occipital transigmoid (POTS) approach. In two patients with preoperative unserviceable hearing, a combined POTS-translabyrinthine approach was adopted. Two patients underwent a combined POTS-transotic approach because of massive erosion of the carotid canal. A modified transcochlear approach type D with posterior rerouting of the facial nerve and transection of the sigmoid sinus and jugular bulb was performed in two patients with a huge cerebellopontine angle tumor component with extension to the prepontine cistern together with massive involvement of the petrous bone and middle ear and encasement of the vertical and horizontal segments of the intrapetrous carotid artery. In one patient with evidence of a dominant sinus on the site of the tumor, a subtotal tumor removal via an enlarged translabyrinthine approach (ETLA) was planned to resect the intradural component of the tumor. Two patients in our series underwent a planned staged procedure on account of a huge tumor component in the neck. One of these patients underwent a first-stage infratemporal fossa approach type A to remove the tumor component in the neck; the second-stage intradural removal of the tumor was accomplished via an ETLA. The last patient underwent a first-stage modified transcochlear type D approach to remove the intradural tumor component followed by a second-stage transcervical procedure for removal of the extracranial component. Gross total tumor removal (Simpson grade I-II) was achieved in 11 (84.6%) cases. Subtotal removal of the tumor was accomplished in two patients. Good facial nerve function (grades I and II) was achieved in 46.1% of cases, whereas acceptable function (grade III) was achieved in the remaining cases 1 year after tumor removal. Hearing was preserved at the preoperative level in all four patients who underwent surgery via the POTS approach. After surgery, no patient recovered function of the preoperatively paralyzed lower cranial nerves. A new deficit of one or more of the lower cranial nerves was recorded in 61.5% of cases. Surgical resection is the treatment of choice for jugular foramen meningiomas. Among the various surgical techniques proposed for dealing with these lesions, we prefer the POTS approach alone or combined with the translabyrinthine or transotic approaches. Despite the advances in skull base surgery, new postoperative lower cranial nerve deficits still represent a challenge.

Giant dumbbell foramen magnum neurinomas presenting as posterior neck masses: Single-stage removal by posterior midline approach

Two patients with giant dumbbell foramen magnum neurinomas are reported. The intradural component was located anterior to the cervicomedullary junction while the extradural and extraspinal portion of the tumor had grown large enough to present as a neck swelling. In both patients total surgical removal was achieved by a single-stage posterior midline approach. Both patients had complete neurological recovery.

Solitary Fibrous Tumor Arising from Cranial Nerve VI in the Prepontine Cistern: Case Report and Review of a Tumor Subpopulation Mimicking Schwannoma

The authors present a report of a solitary fibrous tumor (SFT) arising from the intradural component of the VIth cranial nerve as it travels through the prepontine cistern. SFTs of the central nervous system are extremely rare entities that clinically masquerade as dural-based lesions, such as meningiomas or hemangiopericytomas. Because of their infrequency and clinical similarity to other central nervous system (CNS) lesions, diagnosis is largely dependent on pathological features. In this study, the authors define a subpopulation of SFTs that seem to arise directly from nerve, rather than meninges, and clinically mimic the appearance of a schwannoma. The patient was a 29-year-old woman with a several-month history of progressive right arm and leg numbness and mild hemiparesis, with the development of diplopia 2 weeks before admission. Outside imaging revealed a 3.9-cm mass in the prepontine cistern with extension into Meckel's cave and the cavernous sinus, resulting in significant brainstem compression. The patient underwent preoperative angiography with embolization of feeding vessels off of the left meningohypophyseal trunk. The patient was then taken to the operating room by a combined neurosurgical and ear, nose, and throat team, where the patient underwent a retrolabyrinthine/subtemporal craniotomy for tumor resection. During resection of the prepontine component, the tumor was identified as originating from the left Cranial Nerve VI as it traversed through the prepontine cistern. Resection of the tumor component involving the cavernous sinus and Meckel's cave was deferred for follow-up treatment with intensity-modulated radiation therapy. Pathological examination revealed tissue consistent with the diagnosis of SFT. SFTs involving the CNS are rare entities that are almost always diagnosed after tissue is obtained because of their clinical and radiographic similarity to meningiomas. This patient had an SFT masquerading as a VIth cranial nerve schwannoma. Although the natural history of SFTs in the CNS is not completely understood, correct diagnosis is important, given the rate of recurrence found in the more common pleural-based SFT and examples of CNS SFTs with malignant features.

Intradural Disc Herniation at L5-S1 Mimicking an Intradural Extramedullary Spinal Tumor: A Case Report

Intradural lumbar disc herniation is a rare pathological entity. The pathogenesis of intradural lumbar disc herniation is not known clearly. Intradural disc herniations usually occurred at the L4-L5 levels but have also been reported at other levels. However, intradural disc herniation at L5-S1 is quite rare. There are approximately nine reports in the English literature of intraradicular disc herniation at L5-S1. We described a 61-yr-old man with suspected intradural mass at the level of L5-S1 space. The patient presented with pain in the lower back and both lower legs for 4 months and a sudden exacerbation of the symptoms for 3 days. Gadolinium-enhanced magnetic resonance imaging (MRI) demonstrated a large disc herniation at the L5-S1 level with an intradural component. L5 and S1 laminectomy was performed, and dura was swollen and immobile. Subsequent durotomy was performed and an intradural disc fragment was removed. The patient had full recovery in 3 months. Intradural lumbar disc herniation must be considered in the differential diagnosis of mass lesions in the spinal canal. Contrast-enhanced MRI scans are useful to differentiate a herniated disc from a disc space infection or tumor.

Intradural cranial congenital dermal sinuses: diagnosis and management

The congenital dermal sinus (CDS) is a benign tumor-like entity that has unique anatomical and clinical features. We retrospectively examined our data to determine factors associated with adverse outcomes for cranial-based dermal sinuses. We retrospectively examined our data obtained from patients presenting between 1975 and 2002. Sixty-seven patients with a CDS were found. Of these, 20 cases of a cranial CDS were identified, 15 of which had evidence of an intradural component. Surgical treatment of congenital dermal sinuses was accompanied with, in general, excellent results. Poor outcomes were most strongly associated with delays in diagnosis. The most common complications were infection at the surgical site (five patients) and hydrocephalus necessitating ventriculoperitoneal shunt placement (two patients). Permanent neurological deficits were rare. Cranial CDSs are unusual lesions found in children. A majority of these lesions may penetrate the dura and lead to significant complications if not promptly identified and treated in an appropriate and timely fashion.

Cervical Dumbbell Intra-extradural Hemangioblastoma: Total Removal through the Lateral Approach: Technical Case Report.

Extradural hemangioblastomas account for 8 to 12% of all spinal hemangioblastomas. Among them, intra-extradural forms with a dumbbell extension are extremely rare. We report a case of intra-extradural hemangioblastoma involving the C6 cervical nerve root. The patient was a 31-year-old woman presenting with signs of myelopathy and C6 radiculopathy on the right side. A computed tomographic scan and magnetic resonance imaging demonstrated a dumbbell tumor that had developed through the C5-C6 intervertebral foramen. Angiography revealed a well-circumscribed mass with feeders from the vertebral artery and the deep cervical artery. The tumor was totally removed through the lateral approach, with control of the vertebral artery and sacrifice of the C6 cervical nerve root. Limited bone drilling to enlarge the foramen permitted us to reach and resect the intradural component. Histopathological examination confirmed the diagnosis of hemangioblastoma. Follow-up was uneventful. This is the sixth reported case of a cervical dumbbell hemangioblastoma investigated by computed tomographic scanning and MRI but the first one resected via the lateral approach. The lateral approach seems appropriate for surgical resection because it provides primary control of the vascular feeders and access to the extradural and intradural components.

Clinical Characteristics of Spinal Nerve Sheath Tumors: Analysis of 149 Cases

Spinal nerve sheath tumors arise from the spinal nerve root and grow along it. There are two sites at which the growth of a tumor is restricted: the dural aperture for the spinal nerve root and the intervertebral foramen. This article describes the growth pattern of a spinal nerve sheath tumor along the spinal nerve root at various spinal levels. We retrospectively reviewed the records for 149 patients with spinal nerve sheath tumors who were treated between 1980 and 2001. Of these, 176 resected tumors were classified into five groups according to the relationship to the dura mater and/or the intervertebral foramen. Strictly intradural tumors compose 8% of nerve sheath tumors of the first two cervical nerve roots. The percentage of these tumors increased gradually from the high cervical region to the thoracolumbar region, where it was more than 80%. In contrast, the percentage of strictly extradural tumors gradually decreased from the rostral portion to the caudal portion. Similarly, a percentage of tumors extending outside the spinal canal decreased from the rostral portion to the caudal portion. These changes of the growth pattern may be explained by the anatomic features of the spinal nerve roots, which have a longer intradural component at the more caudal portion of the spinal axis. The anatomic relationship of a nerve sheath tumor with the dura mater and the intervertebral foramen varies depending on the level of the tumor. This knowledge may help us to create a strategy for total resection of a nerve sheath tumor.

Anatomy of the combined retrolabyrinthine–middle fossa craniotomy

The goal of combined retrolabyrinthine-middle fossa craniotomy is to provide exposure of both the middle and posterior cranial fossae via a partial petrosectomy and division of the tentorium. Its major benefits over others are that hearing and facial nerve function are preserved and only minimal brain retraction is required. The retrolabyrinthine approach involves a presigmoid posterior fossa craniotomy that preserves the structures of the inner ear. Additionally, a middle fossa craniotomy, extending to the zygomatic root, is performed to gain access to the superior aspect of the temporal bone in the middle cranial fossa. This approach works well in cases of lesions involving the petroclival junction, including petroclival meningiomas, trigeminal schwannomas, epidermoids, and large chondrosarcomas or chordomas with intradural components. The authors describe the surgical technique of this approach.

Cervical neuromas with extradural components: surgical management in a series of 57 patients.

Cervical neuromas with extradural components (intraextradural or strictly extradural forms) are rare. Their resection raises the problems of nerve root preservation, vertebral artery (VA) control, and spinal stability. A series of 57 patients with neuromas (29 neurofibromas, 23 schwannomas, 4 neurofibrosarcomas, and 1 plexiform neurofibroma) was treated during the period of 1980 to 1995, using one of the lateral approaches (antero- or posterolateral approach). The VA was always controlled before resection of the tumor. In cases of intraextradural forms, the intradural component was removed by a complementary laminectomy (three patients) in the early period and then by an oblique corpectomy through the same lateral approach (five patients) in the late period. A laminectomy had been performed in 15 other patients (11 patients with intraextradural neuromas) before they were referred to us. These patients included seven with recurrent neuromas, occurring after an average period of 4.1 years (1-9 yr). Complete resection was achieved in all except two patients, in whom the nerve root reacted positively to intraoperative stimulation and could not be separated from the tumor. One of the patients was subsequently operated on after 2 years. Another recurrence was observed in another patient at 1 year. The four patients with sarcomas died from recurrence within 2 years. The rate of root preservation included an average of 28%, including 43.5% for schwannomas, 18% for neurofibromas, 44% for lower cervical neuromas (C4-C8), and 4.5% for upper cervical neuromas (C1-C3). Worsening of preoperative neurological deficits was observed in only two patients. The VA was always preserved, except in one patient with a sarcoma that was preoperatively occluded. No instability was observed in any of the patients. Complete resection with good neurological results can be achieved in most patients harboring cervical neuromas each with an extradural component by using a lateral approach and VA control. If the root cannot be separated from the tumor, especially in patients with neurofibromas, intraoperative stimulation can help decide whether the root may be divided without incurring postoperative deficit. The lateral approach permits the resection of the extradural as well as the intradural component by a complementary oblique corpectomy. There was no morbidity in relation to VA control as well as no postoperative instability.

Spinal Arteriovenous Malformation

The authors discuss a patient with a large (15 x 10 x 12 cm), bony soft tissue intradural arteriovenous malformation (AVM) who presented with a 20-year history of back pain. Plain radiographs revealed a destructive lesion. Magnetic resonance imaging showed serpentine vascular structures within the thecal sac and lytic bone lesions with multiple level involvement. A Craig needle biopsy by the referring physician, as well as an open biopsy by the authors, caused severe bleeding. There was no evidence of neoplasm. Selective spinal angiography demonstrated a metameric juvenile type AVM whose intradural component was fed by the artery of Adamkiewicz. Because the patient had no neurological deficit on presentation, the options of embolization and then surgery were considered too risky. The patient is being followed conservatively.

Membranous nephropathy associated with spinal schwannoma

Clinical cure was effected in a patient with biopsy-proven membranous nephropathy associated with spinal schwannoma. The renal manifestation of nephrotic syndrome antedated the clinical presentation of the spinal tumor. The proteinuria and edema subsided 4 mths after the complete resection of the intradural component and partial removal of the extradural component of the schwannoma. Careful workup in patients with membranous nephropathy should include not only malignant but also benign tumors.

Intraoperative ultrasound imaging of the spinal cord: Syringomyelia, cysts, and tumors — A preliminary report

Dynamic intraoperative imaging of the spinal cord was done using a real-time ultrasound scanner. Prior to opening the dura mater the neurosurgeon is able to “explore” the intradural space and with a 7.5 MHz transducer visualize the normal spinal cord, including the central canal and the dentate ligaments. Anterior and posterior spinal arteries may be seen in certain patients. In syringomyelia the fluid-filled cavities may be visualized with ultrasound and drained or shunted with intraoperative ultrasound guidance. Spinal cord cysts or cystic components of tumors can be precisely identified and drained using ultrasound. Intramedullary tumors can be demonstrated sonographically, as can the location and extent of intradural extramedullary tumors and tumors that have both extradural and intradural components. Experience to date with intraoperative imaging of the spinal cord and with the real-time ultrasound scanner is very encouraging, and in the future it should allow for a more precise characterization of and operative approach to lesions of the spinal cord.