Surgical treatment of a syringomyelia associated with an idiopathic arachnoid malformation disclosed by preoperative MRI

BACKGROUND

We describe the very rare condition of an idiopathic spinal arachnoid malformation associated with syringomyelia (SM) and depicted on preoperative magnetic resonance imaging (MRI) whose features were confirmed at surgery.

CASE DESCRIPTION

A 34-year-old female suffered from progressive gait impairment because of lower limb palsy and sensory disturbances. MRI demonstrated a bulging membrane at the T6 level that was transversely stretched between the dorsal aspect of the spinal cord and the posterior dura mater. At this level, the spinal cord appeared atrophic and pushed anteriorly against the dura with enlargement of the posterior subarachnoid spaces (SAS) and focal collapse of an associated panmedullar SM. Surgery consisted in releasing the arachnoid malformation and opening the inferior segment of the syringomyelic cavity. Pathological examination revealed a fibro-sclerotic tissue with cellular areas of meningo-endothelial cells. Postoperative neurological status progressively improved but slightly. Three-months and 1 year postoperatively, MRI showed the collapse of the whole SM and restoration of cerebrospinal fluid (CSF) flow at the treated T6 level.

CONCLUSION

Spinal arachnoid malformations associated with SM are very rare and have never been described up to now on MRI. Surgical removal of the causative malformation allows spinal cord decompression and prevents the recurrence of the SM by restoring normal CSF circulation.

Delineation of lateral tentorial sinus with contrast-enhanced MR imaging and its surgical implications

BACKGROUND AND PURPOSE

The lateral tentorial sinus (LTS) has not been well described in the imaging literature. The aim of this study was to investigate the value of MR imaging in assessing the LTS, which may provide guidance for preoperative planning.

METHODS

Fifty-five adult patients underwent MR imaging of the brain. Four neuroradiologists evaluated the studies for delineation of the LTS and its branches. Presence of arachnoid granulation and dominance of the venous drainage also were reported.

RESULTS

An LTS was detected in 104 of 110 lobes. The LTS in each lobe was classified as type I (candelabra) in 30 (28.8%), type II (independent veins) in 22 (21.1%), and type III (venous lakes) in 37 (35.5%); in 15 (14.4%) of the lobes, the LTS was indeterminate. LTS branches were inconsistently detected, with the exception of the vein of Labbé (VL). Five of eight branches were seen in approximately half of the cases. The VL was identified in 94 (85.4%) lobes. Among these, 53 (56.4%) were draining into the LTS and 22 (23.4%) into the transverse sinus; in 19 (20.2%) cases, the terminal portion was not visualized. The right transverse sinus was dominant in 19 (34.5%) patients and the left in 18 (32.7%); codomination was present in 18 (32.7%) cases. At least one arachnoid granulation was seen in the transverse sinus in 27 (49.1%) patients.

CONCLUSION

In many instances, the LTS and VL drainage patterns were well delineated on routine MR images. For selected cases, this information may be crucial during lateral skull base surgery to avoid venous infarct.

Arachnoid veils and the Chiari I malformation

OBJECT

The literature contains scant data regarding variations in anatomy at the level of the foramen of Magendie in patients with Chiari I malformation and syringomyelia.

METHODS

Based on their operative experience and hospital data, the authors detailed the incidence of arachnoid veils found in juxtaposition to the foramen of Magendie in patients with hindbrain herniation. Additionally, radiological studies were retrospectively reviewed in cases in which such an anomaly was noted intraoperatively. Of 140 patients with Chiari I malformation who underwent decompressive surgery, an associated syrinx was demonstrated in 80 (57%). The foramen of Magendie was obstructed by an arachnoid veil in 10 (12.5%) of these patients; once the lesion was punctured, the cerebrospinal fluid drained freely from this median aperture. On retrospective review of imaging studies, none of these anomalous structures was evident. In all patients with an arachnoid veil and syringomyelia resolution of syringomyelia was revealed on postoperative imaging.

CONCLUSIONS

In the absence of a clear pathophysiology of syrinx production, the authors would recommend that patients with syringomyelia and Chiari I malformation undergo duraplasty so that, if present, these veils can be fenestrated.

Effect of craniocervical decompression on peak CSF velocities in symptomatic patients with Chiari I malformation

BACKGROUND AND PURPOSE

Peak CSF velocities detected in individual voxels in the subarachnoid space in patients with Chiari I malformations exceed those in similar locations in the subarachnoid space in healthy subjects. The purpose of this study was to test the hypothesis that the peak voxel velocities are decreased by craniocervical decompression.

METHODS

A consecutive series of patients with symptomatic Chiari I malformations was studied before and after craniocervical decompression with cardiac-gated, phase contrast MR imaging. Velocities were calculated for each voxel within the foramen magnum at 14 time points throughout the cardiac cycle. The greatest velocities measured in a voxel during the cephalad and caudad phases of CSF flow through the foramen magnum were tabulated for each patient before and after surgery. The differences in these velocities between the preoperative and postoperative studies were tested for statistical significance by using a single-tailed Student's t test of paired samples.

RESULTS

Eight patients with a Chiari I malformation, including four with a syrinx, were studied. Peak caudad velocity diminished after craniocervical decompression in six of the eight patients, and the average diminished significantly from 3.4 cm/s preoperatively to 2.4 cm/s postoperatively (P =.01). Peak cephalad velocity diminished in six of the eight cases. The average diminished from 6.9 cm/s preoperatively to 3.9 cm/s postoperatively, a change that nearly reached the significance level of.05 (P =.055).

CONCLUSION

Craniocervical decompression in patients with Chiari I malformations decreases peak CSF velocities in the foramen magnum. The study supports the hypothesis that successful treatment of the Chiari I malformation is associated with improvement in CSF flow patterns.

Intraventricular congenital lesions and colloid cysts

Intraventricular congenital lesions and colloid cysts comprise a rather large spectrum of different pathologic conditions. In most cases, treatment in not warranted unless there is progressive ventricular obstruction with hydrocephalus or growth of the lesion itself, making tissue biopsy and histopathologic diagnosis necessary. Accordingly, a precise neuroradiologic evaluation is of the utmost importance, because most lesions, if not symptomatic, only require clinical and radiologic follow-up.

Syringomyelia and the arachnoid web

Three cases of syringomyelia associated with arachnoid webs are reported. Each patient presented with progressive myelopathy and had thoracic syringes detected on magnetic resonance imaging (MRI). In one patient the web was also visible. At operation a thoracic arachnoid web was found, obstructing the subarachnoid compartment in each patient. One patient had intraoperative ultrasound, which demonstrated caudal web movement with each cardiac systole. The webs were divided and shunts inserted into the syringes. All patients improved clinically, and on follow-up MRI. Arachnoid webs are likely to represent a focal band of arachnoiditis and are difficult to visualise on standard preoperative MR imaging. A reduction in the subarachnoid space compliance with resultant increase in pulse pressure and potentiation of an arterial pulsation driven perivascular flow could explain the associated syringes. Treatment should be aimed at restoring compliance, and involve division of the web with or without shunt insertion.

Microsurgical anatomy of Liliequist's membrane

OBJECTIVE

To investigate the anatomic characteristics of Liliequist's membrane.

METHODS

Liliequist's membrane was studied in eight adult human cadavers under the microscope.

RESULTS

Liliequist's membrane gives rise to three separate arachnoidal sheets: the diencephalic leaf, the mesencephalic leaf, the diencephalic-mesencephalic leaf. The superior margin of the diencephalic leaf between the inferolateral border of the optic tracts and the temporal unci is free. The posterior margin of the diencephalic-mesencephalic leaf is free. The diencephalic leaf and the mesencephalic leaf attach laterally to the mesial temporal surfaces. Liliequist's membrane attaches closely to the hypothalamus. The diencephalic leaf is an accurate landmark which divides the cisterns of the skull base into two groups: pre-Liliequist group and post-Liliequist group. Liliequist's membrane should be opened sharply in order to avoid the injuries to the hypothalamus by blunt operations. In a pterion approach the diencephalic leaf of Liliequist's membrane can be determined according to the relationship with the posterior communicating artery.

CONCLUSIONS

Liliequist's membrane is an important landmark for the operations in the sellar area or skull base. Understanding the microanatomy of Liliequist's membrane may be helpful for us to improve the exposure and minimize the injuries during the operations.

Synchronous subarachnoid drop metastases from a pituitary adenoma with multiple recurrences. Case report

The authors report the case of a 49-year-old man with synchronous drop metastases from a multiply recurrent somatotroph pituitary adenoma. The metastatic lesions were found in the subarachnoid space of the cauda equina and foramen magnum 18 years after the initial diagnosis of the disease. Five transsphenoidal resections had previously failed to cure the sellar tumor. Two of these, performed 4 and 5 years before the patient's current presentation, had been complicated by cerebrospinal fluid rhinorrhea that necessitated lumbar drainage. Resections of the two subarachnoid lesions, separated by 14 months, removed pathologically aggressive pituitary adenomas. There were no signs of local recurrence or subarachnoid dissemination of disease during the postoperative follow-up periods, which lasted 18 and 4 months, respectively. Previous cases of subarachnoid spread of a pituitary adenoma have been associated with multiple intracranial metastases, multiple intraspinal metastases, or widely disseminated disease. This case demonstrates that subarachnoid metastasis of a pituitary adenoma, particularly when it follows multiple operations, is not invariably widely disseminated or associated with a very poor prognosis.

Cranio-cervical decompression for Chiari type I-malformation, adding extreme lateral foramen magnum opening and expansile duroplasty with arachnoid preservation. Technique and long-term functional results in 44 consecutive adult cases -- comparison with literature data

BACKGROUND

Posterior cranio-cervical decompression by opening at least foramen magnum and C1-lamina usually with corresponding dural and arachnoid opening, is the procedure most currently used for treating Chiari I malformation (alone or in association with syringomyelia). To optimize decompressive effects together with reducing risks, a procedure was developed which consists of a sub-occipital craniectomy and a C1 (or C1/C2) laminectomy, plus an extreme lateral Foramen Magnum opening, a "Y" shaped dural incision with preservation of the arachnoid membrane, and an expansile duroplasty employing autogenous periosteum. The purpose of the article is:1. to report the long-term functional results in a consecutive series of 44 adult patients affected by symptomatic Chiari Malformation type I (CM) using the procedure described.2. and to compare this technical modality with the other modalities reported in the literature.

METHOD

This series includes 44 patients harboring CM type I and operated on between 1990 and 2000. 15 patients had CM with syringomyelia (34%) and 29 CM alone (66%). Functional status was evaluated by using the Karnofsky disability scale. Before surgery 37 patients (84.1%) were independent (of whom 13 had syringomyelia) and 7 patients (15.9%) were dependent - i.e., they required assistance - (of whom 2 had syringomyelia). Outcomes were analized with follow-up ranging from 1 to 10 years (4 years on average).

FINDINGS

There was no operative mortality, and surgery did not provoke any neurological aggravation. After surgery all the patients were independent. For the patients with CM only, the averaged Karnofsky score was 90 at latest follow up, versus 76 before surgery. For the patients with syringomyelia, the averaged latest Karnofsky score was 89 after surgery, versus 74 before.

INTERPRETATION

The presented technique was compared with the other surgical modalities reported in the literature. This comparative study shows that cranio-cervical decompression with extreme lateral resection of the posterior rim of Foramen Magnum out to the level of the occipital condyles on either side, associated with an enlargement duroplasty with preservation of the arachnoid membrane, achieved the best results with minimal complications and side-effects.

Glossopharyngeal neuralgia caused by adhesive arachnoid

Glossopharyngeal neuralgia (GPN) is an uncommon disorder characterized by a severe lancinating pain commonly induced by swallowing. When the pain is resistant to medical management, surgical treatment such as microvascular decompression (MVD) or partial rhizotomy is performed. We report a case of glossopharyngeal neuralgia caused by adhesive arachnoid, in which pain disappeared solely by dissection of the peripheral arachnoid around the glossopharyngeal nerve.

Diffuse arachnoidal enhancement of a well differentiated choroid plexus papilloma

INTRODUCTION

The case of a 38-year old man with a histologically benign choroid plexus papilloma arising within the fourth ventricle with en plaque growth around the brain stem and medulla is described in detail. Up to this point this particular growth pattern has not been published and is a rare presentation for this tumour.

CLINICAL PRESENTATION

The patient presented with a 1.5 year history of headache, nausea, and vomiting in the morning. Additional symptoms like blurred vision and gait ataxia lead to hospital admission. MRI demonstrated a homogeneously contrast-enhancing tumour completely filling the fourth ventricle and subsequent obstructive hydrocephalus. In addition Gd enhancement encasing the brain stem, the lower aspect of the medulla and the conus medullaris was seen suggesting a disseminated ependymoma or medulloblastoma.

INTERVENTION

An extensive resection of the tumour in the fourth ventricle and CP angle was performed. Infiltrative growth into the structures of the left CP angle and into the rhomboid fossa hampered complete removal. Surprisingly histological examination revealed a well-differentiated papillary choroid plexus papilloma without signs of anaplasia. On follow up imaging the Gd enhancement encasing the pons vanished completely. A growing cyst adjacent to a small tumour residuum left behind on the floor of the fourth ventricle led to re-operation after 8 months with complete removal.

DISCUSSION

This case presents several biological, neuroradiological and surgical aspects which make it noteworthy and we hope that the informations provided add to the understanding of these tumours, expand the differential diagnostic thinking of lesions which present with diffuse arachnoid Gd enhancement upon first presentation.

Surgical indications and microsurgical anatomy of the transchoroidal fissure approach for lesions in and around the ambient cistern

OBJECTIVE

Opening the temporal part of the choroidal fissure (CF) makes it possible to expose the crural cistern, the ambient cistern, and the medial temporal lobe. We examined the microsurgical anatomy and the surgical indications for use of the trans-CF approach.

METHODS

The microsurgical anatomy encountered in the trans-CF approach for lesions in and around the ambient cistern was studied in three cadavers. On the basis of these cadaveric studies, the trans-CF approach was used during surgery in three live patients with such lesions.

RESULTS

The angiographic "plexal point," which indicates the entrance of the anterior choroidal artery as it enters the temporal horn of the lateral ventricle, was thought to be a key anatomic landmark of the trans-CF approach. A cortical incision for entry into the temporal horn should be made in the inferior temporal gyrus to minimize the potential damage to the optic radiations and to the speech centers. After the CF is opened posteriorly to the plexal point between the tenia fimbria and the choroid plexus, the posterior cerebral artery (PCA) in the ambient cistern can be observed with minimal caudal retraction of the hippocampus. In this study, surgical procedures using the trans-CF approach were successfully performed on patients with high-positioned P2 aneurysms whose PCA ran close to the plexal point or higher, whose medial temporal arteriovenous malformations were fed mainly by the PCA, and whose tentorial hiatus meningiomas protruded into the temporal horn through the CF, with no resulting postoperative visual or memory disturbances.

CONCLUSION

The trans-CF approach is especially useful in surgery for lesions in and around the ambient cistern.

Cranial base approaches for the surgical treatment of aggressive posterior fossa dural arteriovenous fistulae with leptomeningeal drainage: report of four technical cases

OBJECTIVE AND IMPORTANCE

Dural arteriovenous fistulae (DAVFs) with leptomeningeal drainage have an aggressive natural history. Urgent treatment is necessary to arrest neurological deterioration and to prevent the risk of intracranial hemorrhage. In many patients, a primary endovascular approach is the most appropriate and most successful treatment available. In some circumstances, however, surgical intervention is required for complete obliteration. Posterior fossa DAVFs are generally deep-seated and difficult to gain access to with standard surgical approaches. The advent of cranial base surgery allows 360-degree access to the draining venous complex or sinus via extradural bone removal.

CLINICAL PRESENTATION

Four patients with posterior fossa DAVFs presented to the neurosurgical service at our institutions. One DAVF was located at the craniocervical junction, and three were tentorial DAVFs of the superior petrosal sinus. All four patients were treated surgically with extradural bone removal.

INTERVENTION

Postoperative angiography documented complete obliteration of all four DAVFs. All patients had normal recoveries, with the exception of one patient who experienced persistent temporal lobe seizure activity as a result of the presenting hematoma. One patient died of unrelated causes 2 years after surgery. One postoperative temporal lobe hematoma required evacuation.

CONCLUSION

Recent advances in cranial base techniques have allowed the successful obliteration of aggressive posterior fossa DAVFs with acceptable morbidity. The use of these techniques should be considered in selected patients who cannot be treated with endovascular approaches.

Recurrence of convexity meningiomas: tumor cells in the arachnoid membrane

BACKGROUND

It remains open to debate why totally removed benign meningiomas recur. Two recurrent cases forced us to reconsider something corresponding to their recurrence that we had overlooked during Simpson grade I surgery.

METHODS

This study is based on 24 recent and 9 earlier cases in which benign convexity meningiomas were totally removed by Simpson's grade I surgery. Tough or thick arachnoid membranes continuing to normal arachnoid membranes and contiguous to meningiomas but different from dura mater were encountered in 11 recent and at least 2 earlier cases. Such thick arachnoid membranes were left in place or only partially resected in two earlier cases but extensively resected in all recent cases.

RESULTS

Light microscopy showed clusters of meningioma cells not in the removed dura mater but in the thick arachnoid membranes of an earlier case and 10 out of the 11 recent cases. Six and twelve years after initial surgery, recurrence of the 2 earlier cases was confirmed at subsequent surgery or diagnosed by neuro-imaging. By contrast, neuro-imaging from 30 to 132 months after initial surgery showed no recurrence in the 10 recent cases. A follow-up study over 5 years showed a significant difference in recurrence between Simpson's grade I surgery with and without extensive removal of surrounding thick arachnoid membranes (Fisher's exact test: p < 0.05).

CONCLUSION

This study emphasizes the possibility that thick arachnoid membranes contiguous to meningiomas and continuous to normal arachnoid membranes, involving clusters of tumor cells, may relate to meningioma recurrence.

Ectopic arachnoid granulomatosis: a case report

BACKGROUND

Arachnoid granulation can sometimes show hypertrophy, developing extensively apart from the venous sinus, and in that case, a differential diagnosis should be made between this granulation and tumors. In this case, we hypothesized that cerebrospinal fluid was absorbed in the region of abnormal stains revealed by angiography.

CASE DESCRIPTION

A 67-year-old female with headache was admitted to our hospital. A plain radiograph revealed accumulated numerous osteolytic lesions in the right frontal bone. T1-weighted magnetic resonance (MR) images demonstrated mixed-intensity lesions. On the T2-weighted MR images, we observed that the lesions were mixed, with areas of the same intensities as gray matter and cerebrospinal fluid. An abnormal vascular stain from the frontal branch of the middle meningeal artery was confirmed. After a craniotomy, numerous white granular masses were observed. These masses had penetrated the dura mater and adhered rigidly to the arachnoid membrane. Histological examination revealed them to be normal arachnoid granulations and villi.

CONCLUSION

This case was diagnosed as an ectopic arachnoid granulomatosis. No case report has previously been published describing numerous arachnoid granulations away from the venous sinuses.

Thoracic spine arachnoid ossification with and without cord cavitation. Report of three cases

Thoracic spine arachnoid ossification is a relatively rare disease that affects mainly women and causes sensory, motor, and sphinctal symptoms associated with inferior limb pain. Based on three cases, the authors comment on pathogenic and surgery-related aspects of the disease. The patient in Case 1 was followed over the course of 23 years. Spinal cavitation is highlighted in Case 2, and yellow, gross, half-ring ossification is described in Case 3. Calcium deposits usually occur in the middle and lower thoracic spine where the majority of trabeculated arachnoid cells are located. Operative treatment does not interrupt the ossification process, which continues over time, causing progressive deterioration in the patient. Spinal cavitation can occur due to spinal cord tethering, stretching, and central cord edema formation, accompanied by cerebrospinal fluid blockage and pulse pressure changes. The results of surgical intervention are poor, offering short-term recovery with later deterioration. Multiple pathogenic factors are involved in this clinical syndrome including metabolic changes.

Hypothalamic hamartoma associated with an arachnoid cyst

A hypothalamic hamartoma associated with an arachnoid cyst in an 8-year-old boy is reported herein. He presented with precocious puberty, and neuroimaging studies demonstrated a solid mass in the prepontine cistern and a huge arachnoid cyst in the left cranial fossa. The mass appeared isointense to the surrounding cerebral cortex on T1-weighted magnetic resonance images, hyperintense on T2-weighted images, and was not enhanced after administration of Gd-DTPA. The patient underwent a left frontotemporal craniotomy and a cyst-peritoneal shunt was inserted. Histological features of the cyst wall and the mass were characteristic of an arachnoid cyst and hamartoma, respectively. While a hypothalamic hamartoma associated with an arachnoid cyst is rare, such a case may help clarify the geneses of both anomalous lesions.

Liliequist's membrane is a fold of the arachnoid mater: study using sheet plastination and scanning electron microscopy

OBJECTIVE

The subarachnoid space consists of a number of distinct subarachnoid cisterns. They are separated from each other by trabecular walls, one of which is Liliequist's membrane. The aim of this study was to investigate the anatomic characteristics of Liliequist's membrane.

METHODS

The study used a combined approach, consisting of the modified E12 sheet plastination method for 3 adult cadavers and gross anatomic dissection for 35 cadavers, 2 of which were further examined using scanning electron microscopy.

RESULTS

The results from this study indicate that 1) Liliequist's membrane is an avascular fold of the arachnoid mater that lacks openings and spreads out laterally, being in direct continuity with the arachnoid mater covering the tentorium; 2) the carotid-chiasmatic walls, which separate the chiasmatic cistern and carotid cisterns and had been considered to be parts of Liliequist's membrane, are vascular and incomplete trabecular walls and should not be considered parts of Liliequist's membrane; and, 3) as a fold of the arachnoid mater, Liliequist's membrane is not directly attached to the temporal lobes and oculomotor nerves.

CONCLUSION

Liliequist's membrane is a double-layer fold of the arachnoid mater and has anatomic characteristics different from those of arachnoid trabecular walls.

Liliequist's membrane in minimally invasive endoscopic neurosurgery

Liliequist's membrane, an arachnoid condensation extending from the upper border of the dorsum sellae to the anterior edge of the mammillary bodies and formerly a relatively insignificant structure, has been found to be extremely important in the neuroendoscopic management of hydrocephalus. Failure to open this membrane can lead to the failure of third ventriculostomies.

MR imaging features of clear-cell meningioma with diffuse leptomeningeal seeding

Clear-cell meningioma is a rare disease entity showing a more aggressive nature, clinically, than those of other subtypes of meningioma. It occurs in younger persons and commonly in the spinal canal. The recurrence rate has been reported to be as high as 60%. We present a case of clear-cell meningioma in a 17-year-old man in whom initial MR imaging showed localized leptomeningeal enhancement that had progressed into the entire subarachnoid space after surgical resection of the primary tumor.

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.

Extensive arachnoid ossification with associated syringomyelia presenting as thoracic myelopathy. Case report and review of the literature

The authors present the case of progressive thoracic myelopathy caused by the extensive ossification of the arachnoid membrane and associated intramedullary syrinx. Based on their findings and results of the literature search, they describe a pathological basis for this rare condition, discuss its incidence and symptomatology, and suggest a simple classification for various types of the arachnoid ossification. They also discuss the magnetic resonance imaging features of arachnoid ossification and associated spinal cord changes. The particular value of plain computerized tomography, which is highly sensitive in revealing intraspinal calcifications and ossifications, in the diagnostic evaluation of patients with a clinical picture of progressive myelopathy is emphasized.