Surgical results of 100 intramedullary tumors in relation to accompanying syringomyelia

Disturbances of cerebrospinal fluid flow attributable to arachnoid scarring cause interstitial edema of the cat spinal cord

OBJECTIVE

Spinal arachnoid scarring may be caused by trauma, inflammation, surgery, spinal instability, degenerative diseases, or malformations and may lead to progressive neurological deficits and syringomyelia. We wanted to investigate the effects of focal arachnoid scarring in the cervical spinal canal of cats on pressures in the subarachnoid space and spinal cord tissue, as well as on spinal cord histological features.

METHODS

Twenty-nine adult cats were used for this study. Nine animals served as control animals, whereas 20 animals received a focal arachnoid scar at C1-C2, which was produced by placement of a kaolin-soaked fibrin sponge on the posterior surface of the spinal cord. After 4 months, pressure recordings above and below the scar, in the subarachnoid space and spinal cord, were performed. Elasticity measurements were performed with small bolus injections. Morphometric analyses of brain and ventricle volumes, sizes of the central canal, and sizes of the perivascular spaces in gray and white matter were also performed.

RESULTS

No animal developed clinical or neurophysiological evidence of neurological symptoms at any time. In the kaolin-treated group, pressure recordings revealed a significant increase in the subarachnoid pressure at C1, because of the cerebrospinal fluid flow obstruction. Pressure gradients tended to increase at all measuring points. A significant difference was detected between the spinal cord and subarachnoid space at C2, where the intramedullary pressure exceeded the subarachnoid pressure. Elasticity was significantly increased in the spinal cord at C2. Intracranially, no evidence of hydrocephalus was observed. In the spinal cord, perivascular spaces were significantly enlarged in the posterior white matter above the arachnoid scar and in the central gray matter below the area of scarring in the cervical cord.

CONCLUSION

Arachnoid scarring at C1-C2 produces an interstitial type of edema in the central gray matter below the area of scarring in the cat cervical cord, because of altered cerebrospinal fluid and extracellular fluid flow dynamics. These changes may be interpreted as the initial stage in the development of syringomyelic cavities.

Neoplasms of the spinal cord and filum terminale: radiologic-pathologic correlation

Intramedullary spinal cord neoplasms are rare, accounting for about 4%10% of all central nervous system tumors. Despite their rarity, these lesions are important to the radiologist because magnetic resonance (MR) imaging is the preoperative study of choice to narrow the differential diagnosis and guide surgical resection. On contrast materialenhanced MR images, intramedullary spinal tumors almost always manifest as expansion of the spinal cord and show enhancement. Syringohydromyelia and cystic lesions are frequently associated with intramedullary tumors. Nontumoral cysts tend to be located at the poles of the tumors and do not enhance on contrast-enhanced MR images, whereas cysts within the substance of the tumor are considered tumoral cysts and typically demonstrate peripheral enhancement. Spinal cord ependymomas are the most common type in adults, and cord astrocytomas are most common in children. Both entities constitute up to 70% of all intramedullary neoplasms. A central location within the spinal cord, presence of a cleavage plane, and intense homogeneous enhancement are imaging features that favor an ependymoma. Intramedullary astrocytomas are usually eccentrically located within the cord, are ill defined, and have patchy enhancement after intravenous contrast material administration. Even with these characteristics, it may not be possible to differentiate these two entities on the basis of imaging features alone. Cord hemangioblastomas are the third most common type of intramedullary spinal tumor. Gangliogliomas commonly extend over more than eight vertebral segments. Paragangliomas and primitive neuroectodermal tumors have an affinity for the filum terminale and cauda equina. Other spinal cord tumors include metastatic disease, which is characterized by prominent cord edema for the size of the enhancing portion, and primary lymphoma.

Pediatric intramedullary spinal cord tumors: special considerations

Intramedullary spinal cord tumors (IMSCTs) of the pediatric population are rare and comprise thirty-five percent of intraspinal neoplasms. Low-grade astrocytomas predominate; ependymomas increase in frequency with ascending age and become the most frequent IMSCT in adults. Gangliogliomas are very rare in adults but comprise nearly thirty percent of tumors in children under three years of age. The cervical spine is the region of the spine most affected. Pain is the most common presenting symptom with weakness, gait deterioration, torticollis also frequently reported. Hydrocephalus occurs with greater frequency than in adult patients and often requires a shunt. Motor and sensory evoked potential monitoring is routinely utilized. Osteoplastic laminotomy is performed to forestall the development of progressive spinal deformity. Gross total resection is feasible in most ependymomas and results in surgical cure. Astrocytomas are infiltrating neoplasms and gross total resection is occasionally possible only in the pediatric population. However, the role of radical resection of low-grade fibrillary astrocytomas of the spinal cord in children has not been definitively demonstrated in the literature. Outcome for low-grade astrocytomas is better in children than adults, but not as favorable as that for ependymomas. Malignant tumors have dismal outcomes and surgery in these patients serves only to provide a diagnosis.

Spinal cord astrocytomas: presentation, management and outcome

Intramedullary spinal cord astrocytomas are uncommon tumors. They are the most common spinal cord tumor in children and in adults are second only to ependymomas in frequency of occurrence. Low-grade histology predominates with high-grade lesions comprising only ten to fifteen percent of pediatric tumors and a slightly higher proportion in adults. Presenting symptoms typically evolve over months to years with regional back pain the most commonly reported initial complaint. Malignant tumors produce rapid neurological deterioration. MRI is the diagnostic modality of choice: spinal cord astrocytomas are iso- to slightly hypointense on T1, hyperintense on T2 and commonly have associated cysts. They enhance less intensely and are more eccentric than ependymomas. The goals of surgical intervention are to obtain a tissue diagnosis and resect as much tumor as possible without adversely affecting neurological function. Astrocytomas are infiltrating neoplasms and total resection is not generally possible. Somatosensory and motor evoked potential monitoring are routinely used but it is unclear if they improve outcomes. The operating microscope and bipolar cautery are essential surgical tools; the ultrasound and ultrasonic surgical aspirator are useful surgical adjuncts. Laminectomy is performed on adults while laminoplasty is favored for pediatric patients. Outcome for low-grade astrocytomas is less favorable than that of ependymomas with regard to both recurrence and function though many have prolonged survival. There is no correlation of extent of resection and recurrence. Outcome for high-grade tumors is extremely poor; tumor progression is relentless; median survival is thirteen months in children and six months in adults.

Intramedullary ependymomas: clinical presentation, surgical treatment strategies and prognosis

Intramedullary ependymomas are rare tumors but comprise the majority of intramedullary glial neoplasms in the adult. These tumors are benign, slow-growing lesions which are optimally treated with gross-total surgical resection without adjuvant therapy. This objective can be attained safely in a majority, of patients. Post-operative functional outcome is related to pre-operative functional status. Hence, early diagnosis, prior to symptomatic progression, is critical to the successful treatment of these tumors. Adjuvant therapy is indicated for the rare malignant or disseminated tumor or following sub-total resection.

Hemangioblastomas and other uncommon intramedullary tumors

Astrocytoma and ependymoma make up 90% of intramedullary tumors between them. However, a host of less common tumors form the remaining 10%: these include hemangioblastomas, subependymomas, gangliogliomas and other neuronal variants, metastases from extraneural cancers, and a host of other lesions that typically occur intracranially but which present on rare occasions in the intramedullary location. Most neurosurgeons will encounter the unusual tumors of the spinal cord described in this review only a few times during their professional careers, but it is nevertheless important to recognize the distinct radiological and intraoperative features of those for which significant series of patients have been accumulated. Metastases and germinomas aside, the other neoplasms described here are relatively benign in their clinical and histological behavior, and can be meaningfully resected by careful microsurgical technique.

Surgical results for spinal meningiomas

Among a series of 782 spinal tumors, 130 spinal meningiomas in 117 patients were operated in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany, between 1977 and 1998. Patients were followed postoperatively for up to 13 years (mean 20 +/- 33 months). Comparing the period of 1977 through 1987, before magnetic resonance imaging (MRI) was available, to the period of 1988 to 1998 revealed that the average history until diagnosis shortened by about 6 months during the second decade of this study (24 +/- 33 to 18 +/- 29 months; not significant). Consequently, the preoperative Karnofsky Score increased significantly (59 +/- 15 and 66 +/- 16; p < 0.05). The rates of complete resection and the postoperative neurological outcome, however, remained unchanged. Even though the overall prognosis of neurological deficits is favorable after complete resection of a meningioma, a subset of 18 patients had either en plaque growing or recurrent tumors that were more likely to be removed incompletely and to cause postoperative neurological problems, with a significantly worse Karnofsky Score after 1 year (57 +/- 12 and 77 +/- 12, respectively; p < 0.01) and a significantly higher recurrence rate after 5 years (86.7% and 20.4%, respectively; log rank test p = 0.0014). In conclusion, a favorable postoperative neurological outcome requires complete resection of the spinal meningioma. The advent of MRI has shortened the time until diagnosis and made it possible to perform surgery before severe deficits have occurred, but did not have a major impact on postoperative results. En plaque and recurrent meningiomas remain surgical challenges, as infiltration of surrounding structures and associated arachnoid scarring may render complete resection difficult to achieve.

Results of microsurgical treatment for intramedullary spinal cord ependymomas: analysis of 36 cases

OBJECTIVE

Although intramedullary spinal cord ependymomas are amenable to surgical total resection, some ependymomas have been associated with severe surgical morbidity. The aim of this study is to determine what factors affect surgical morbidity.

METHODS

Thirty-six consecutive patients who underwent surgical removal of an intramedullary spinal cord ependymoma between September 1980 and June 1998 were studied retrospectively. This series includes 19 women and 17 men between the age of 12 and 67 years (mean age, 41.2 yr). The location of the tumors was cervical in 24 cases, cervicothoracic in 3 cases, thoracic in 7 cases, and conus in 2 cases. At surgery, complete removal was achieved in 34 patients and subtotal removal was performed in the remaining 2.

RESULTS

There has been no tumor recurrence in any patient except one who had an anaplastic ependymoma after a mean follow-up period of 56 months. The surgery improved neurological status in 14 of the 36 patients (39%). However, five patients (14%) experienced persistent deteriorations in clinical grade caused by surgery. Four of the five patients harbored benign ependymomas in the thoracic cord and characteristically demonstrated arachnoid scarring and cord atrophy at surgery, indicating that tumors had been present for a long time.

CONCLUSION

Surgical removal of intramedullary ependymomas is beneficial to patients. However, the thoracic cord may be susceptible to surgical manipulations for intramedullary ependymomas. In addition, intraoperative findings of arachnoid scarring and cord atrophy are ominous for surgical morbidity.

Radical excision of intramedullary cavernous angiomas

OBJECTIVE

This is a retrospective study of patients with surgically treated, intramedullary cavernous malformations. We conducted the study to elucidate the outcomes of the patients, as well as potential pitfalls in their care.

METHODS

A series of 12 patients underwent radical excision of intramedullary cavernous malformations between 1986 and 1996. All lesions were diagnosed by magnetic resonance imaging. Although seven patients experienced recurrent episodes of pain and sensorimotor disturbances, the histories of the other five patients were relevant for slowly progressing deficits (mostly sensory).

RESULTS

All cavernomas were completely resected. No deaths were recorded. In follow-up examinations (5-102 mo after discharge), there was no evidence of recurrence, either clinically or in control magnetic resonance imaging scans. In follow-up examinations, two patients demonstrated sensory deficits that were slightly more pronounced than the preoperative deficits. The postoperative neurological status of 3 of 12 patients was unchanged, compared with the preoperative status. The status of the remaining seven patients had improved. For four patients there was effective functional improvement, and for three others there was complete postoperative relief of pain. Deficits of the long tracts were less prone to recover.

CONCLUSION

The clinical course of cavernous malformations may be difficult to distinguish from that of spinal dural arteriovenous malformations or focal demyelinating disease. In the latter case, even magnetic resonance imaging results could be deceptive. Radical resection of these malformations is feasible, with relatively low surgical morbidity, provided that the preoperative deficits of the patients are limited. Given the generally progressive course of the illness and the few acute catastrophic myelopathies, complete excision is advocated whenever malformations are symptomatic.

Secondary syringomyelia due to intramedullary spinal cord metastasis. Case report and review of literature

Intramedullary spinal cord metastasis is relatively rare. We describe a patient having intramedullary spinal cord metastasis associated with syringomyelia, confirmed by magnetic resonance imaging, in a patient who had poorly differentiated carcinoma of the lung. The patient responded to treatment with steroids and radiotherapy, with complete resolution of neurologic symptoms and syringomyelia.

Surgery of intramedullary spinal cord tumors

The diagnosis and management of intramedullary spinal cord tumors have been significantly influenced by new diagnostic and surgical tools such as MRI, ultrasonic aspiration, intraoperative ultrasound, and evoked potential monitoring. In this study we compared the surgical results of our earlier cases using conventional methods with more recent cases using these new methods. We report our experience based on 44 adult cases. Histologic diagnosis revealed ependymoma (20 cases), astrocytoma (15 cases), glioblastoma multiforme (1 case), and other histologic diagnoses (8 cases). We performed 20 gross total resections, 19 partial resections, and 5 biopsies. The mean follow-up period was 25.8 months (3 months-10 years). Surgical results were improvement in 11 patients (25%), stabilization in 24 (54%), and deterioration in 9 (20%). The first 28 cases (group A) were diagnosed using conventional myelography and CT myelography. The more recent 16 cases (group B) were diagnosed with MRI and operated on using techniques such as ultrasonic aspiration, intraoperative monitoring and ultrasound imaging. Radical surgery (total excision) was performed in 36% (n = 10) of group A, while it was possible in 62% (n = 10) of group B. Deterioration after operation was noted in 28% (n = 8) of group A, but only 6.2% (n = 1) of group B. These results stress the importance of a preoperative MRI scan and the positive effects of intraoperative ultrasound imaging, ultrasonic aspiration, and evoked potential monitoring on surgical results. With the help of these tools, most intramedullary spinal cord tumors may be diagnosed and treated surgically with significantly decreased risk. Radical surgery was possible in as many as 62% of our more recent patients. Partial resection with radiotherapy should be confined to patients with high-grade astrocytomas.

Intramedullary tuberculoma of the spinal cord with syringomyelia

We describe a patient with a presumed intramedullary tuberculoma treated only with antituberculous therapy. MRI showed a ring-enhancing annular lesion in the thoracic spinal cord with a distant syringomyelic cavity, which improved after therapy. MRI in this case allowed us not only to achieve a presumptive diagnosis but also to assess the therapeutic response, making surgical exploration unnecessary.

Hemangioblastomas of the spinal cord and the brainstem: diagnostic and therapeutic features

Hemangioblastomas of the spinal cord and the brainstem make up 4% of all spinal tumors and are less common than cerebellar hemangioblastomas. CT and MRI are essential for preoperative diagnosis. Nevertheless, cerebral and spinal angiography are also mandatory, since they allow a detailed study of the vascular situation, which is decisive for exact planning of a surgical strategy. The purpose of this study was to evaluate the diagnostic and therapeutic factors which influence surgical morbidity and postoperative outcome. Twelve patients harbouring spinal(8 cases) or medullary (4 cases) hemangioblastomas, all symptomatic with sensorimotor deficits corresponding to the level of the lesion were evaluated. All patients were treated in our department between December 1989 and September 1994. Complete resection of the lesion was achieved in each case. Postoperatively, none of the patients showed deterioration. Nine patients had immediate postoperative improvement of neurological signs and symptoms; in three patients the initial neurological deficits remained unchanged during the in-patient period. Late postoperative outcome demonstrated a clear improvement; in only one patient was there no change of the clinical signs, while in the other 11 patients a significant improvement of pre-existing neurological deficits was experienced. We conclude that microsurgical resection of spinal and medullary hemangioblastomas with low morbidity is feasible.

Surgical results of spinal meningiomas

We report on 94 spinal meningiomas in 88 patients operated between September 1977 and August 1994 which were followed for up to 13 years (mean 24 +/- 35 months). Complete tumour resection led to postoperative improvement of every preoperative deficit or symptom. En plaque, recurrent, anterior, and low thoracic or lumbar meningiomas were likely to be resected incompletely. Partial tumour removal, arachnoid scarring, primary dural suture, recurrent meningiomas, and male sex were independent factors predisposing to clinical recurrence. Cauterization instead of resection of the tumor matrix was not associated with a higher recurrence rate.