Diagnostic value of computed tomography in recurrent pain after discectomy.

Intravenously enhanced computed tomography (CT) was used in patients in whom the differential diagnosis between recurrent herniated disc and postoperative scar was considered. Enhanced CT images demonstrated postoperative herniated discs more accurately than clinical criteria, myelography, or plain or postmetrizamide CT. The scar tissue shows contrast enhancement, but recurrent disc herniation does not. Therefore, contrast-enhanced CT is considered to be a valuable aid in distinguishing between recurrent disc herniation and hypertropic scar formation.

Recurrent post-discectomy pain. CT--surgical correlation.

Diagnostic evaluation of the patient with recurrent lumbosacral radiculopathy following lumbar laminectomy and discectomy represents a difficult task for the radiologist. Neither non-enhanced CT nor myelography have permitted reliable differentiation between postoperative extradural fibrosis (scarring) and recurrent disc herniation. However, CT following intravenous contrast infusion has been reported by several investigators to allow differentiation of these two entities. A series of 13 patients is reported with correlation between the findings on postcontrast CT and at reoperation. In 5 patients who exhibited variable contrast enhancement of an extradural soft tissue mass without a discreet lucent component on postcontrast CT, operative reexploration revealed only scar tissue. In 8 patients in whom postcontrast CT demonstrated a discreet non-enhancing extradural mass (partially surrounded by a thin enhancing rim of soft tissue in all but one), recurrent disc herniation together with an overlying band of scar was found and resected at reoperation. The strong positive correlation between CT and operative findings in this series suggests that postcontrast CT may well prove to be a reliable method for preoperative differentiation of recurrent disc herniation from extradural scarring.

Spinal vascular tumors: dilemmas in diagnosis and management.

Three case reports of spinal vascular tumors illustrate the need for well-organized and thorough neuroradiological and neurosurgical planning to achieve an initial cure without delay and to avoid inadequate operative procedures.

Dynamic computed tomography: intracranial applications.

Rapid sequential computed tomography of the brain after the bolus injection of contrast material provides invaluable information as to the characteristic blood flow of intracranial lesions in a noninvasive manner. Plotted dynamic curves permit accurate diagnosis of particularly difficult cases of infarcts and neoplasms. Dynamic computed tomographic (CT) scanning has become a part of the CT work-up for infarcts, which has allowed their earlier demonstration, detected as areas of hypoperfusion not clearly evident on an initial conventional CT study. Quantitative assessment of vasogenic edema and hypoperfusion are helpful in establishing the diagnosis of infarction and neoplasia. Orbital and parasellar neoplasms can be distinguished accurately from vascular lesions. Dynamic CT studies complemented conventional film screen arteriography in the evaluation of three cases of intracavernous internal carotid artery aneurysm, defining thrombus formation and wall thickness and thus influencing the therapeutic approach. In addition, this modality is useful in differentiating jugular fossa neoplasm from vascular malformation. This review elaborates on the technique involved in dynamic CT scanning and the subsequent results.

Intracerebral hematoma after evacuation of chronic extracerebral fluid collections.

Among 140 cases of chronic extracerebral fluid collections treated surgically, 7 cases (5%) of intracerebral hematoma occurring immediately after drainage were encountered. In none of the patients was a preoperative intracerebral clot or contusion identified by either computed tomographic scan or angiography. One patient had pre-existing systemic hypertension. Five of the patients had chronic subdural hematomas, 1 had a subdural hygroma and had been previously radiated for medulloblastoma, and 1 patient had a middle fossa arachnoid cyst. Four of the group had had craniotomies and three had undergone trephination for the primary lesion. The postoperative intracerebral hematomas were manifest by rapid deterioration of consciousness and focal neurological findings occurring usually immediately (but, in 2 cases, a few days after) the original procedure. Five patients underwent secondary craniotomy and 2 had external drainage. Despite rapid treatment, 2 of the patients died, 4 were left with severe disability, and only 1 survived intact. None of the patients had identifiable coagulopathy, and only 1 patient was hypertensive in the immediate postoperative period. The factors that all of the patients had in common were preoperative increased intracranial pressure and shift of the midline structures, as well as rapid surgical decompression of the initial lesion. Possible pathogenic mechanisms include hemorrhage into previously undetected areas of contusion, a sudden increase in cerebral blood flow combined with faulty autoregulation, and damage to parenchymal vessels secondary to rapid intra- or postoperative shift of the intracranial contents. Perhaps this devastating complication can be avoided if closed system drainage is used for the treatment of chronic surface collections.

"Subacute" postoperative subdural empyema.

Although subdural empyema (SDE) has long been a recognized postoperative complication, little has been written to suggest that SDE's following operative procedures are different from those occurring in patients who have not had previous surgery. Four cases of postoperative SDE are reported which seem to have several distinguishing features and are grouped under the title of "subacute" subdural empyemas. These include: occurrence in a previous craniotomy site, a prolonged course, the insidious onset of symptoms, and the absence of signs of constitutional illness. The presence of an inner subdural membrane which limits the size of the empyema and separates it from the underlying brain is thought to be the reason for the relatively benign nature of the presenting symptoms and the extremely good prognosis. Computerized tomography scanning was not able to provide a preoperative diagnosis of empyema in any case.

Long term cognitive effects of stereotactic thalamotomy on non-parkinsonian dyskinetic patients.

Pre- and postoperative neuropsychological evaluation focusing on processing, memory, attentional and emotional deficits was performed on 10 non-parkinsonian dyskinetic patients undergoing single radiofrequency ventralateral (VL) unilateral thalamotomy. Patients carried a diagnosis of either familial tremor or multiple sclerosis and it was found that only in the cases of familial tremor was there no residual loss on long-term evaluation with consistent improvement postoperatively.

Successful treatment of a single cerebral metastasis from bronchogenic carcinoma.

Three patients with long-term survival after operations for a single cerebral metastasis from pulmonary cancer are reported as exceptions to the poor prognosis commonly associated with this disease. Evaluations at nine, five, and six years, respectively, after surgical treatment showed no evidence of recurrence. The pathology and the ramifications of computerized tomography and radiotherapy with respect to management of cerebral metastasis are discussed. In selected cases, aggressive treatment of both the primary and secondary lesions may result in prolonged and useful survival and even permanent cure.

Hemiballismus complicating stereotactic thalamotomy.

The pathology of poststereotactic hyperkinesis has been rarely documented and the pathophysiology is still poorly understood. In a case of hemiballismus following thalamotomy for parkinsonism, detailed anatomical studies showed bilateral cortical pseudolaminar necrosis and no involvement of the subthalamic nuclei by the thalamic lesions. The structural and functional effects of surgical lesions upon the preexisting pharmacological abnormalities present in parkinsonism probably constitute the substrate necessary for occurrence of hemiballismus following stereotactic surgery.

Sphenoethmoidal encephalocele: a case report with review of the literature.

A rare case of sphenoethmoidal encephalocele with detailed pathological studies is reported. Only a few cases have been documented and were reviewed. The etiology and embryology of the congenital malformation remains speculative with an agreement on their development at an early embryonic stage. The mass presenting in the nasopharyngeal cavity remains often undetected unless causing respiratory embarrassment and is frequently misdiagnosed. Thorough radiological investigations detect the bone defect and outline the extent of the herniated mass and associated cerebral abnormalities. Small lesions have been successfully repaired. Larger ones prove less amenable to surgery and carry a high mortality.

Meningiomas causing spontaneous intracranial hematomas.

Four cases of spontaneous intracranial hematomas caused by unsuspected meningiomas are reported. Nine previous cases were found in the literature and the entire series of 13 cases is reviewed. Because of their unusual clinical presentation, these cases were not diagnosed correctly prior to radiological studies. Hypertension, trauma, and blood dyscrasia played no significant pathogenetic role. The histological features of these hemorrhagic meningiomas are described, and the importance of adequate radiological investigations and early radical surgery is stressed.

Sensory and nonsensory portions of the nucleus "ventralis posterior" thalami of chimpanzee and man.

In man and chimpanzee, the large-celled region in the posteroinferior portion of the lateroventral thalamic mass, commonly called the nucleus ventralis posterior thalami, is separated cytoarchitecturally into two regions. The anterior portion is called the nucleus ventrointermedius (Vim) and the posterior part, the nucleus ventrocaudalis (Vc). In the chimpanzee it was found that most of the fibers from the superior cerebellar peduncle entered Vim on the way to distribution in the anterior half of the lateroventral thalamic mass. Fibers from the posterior spinal column (medial lemniscus) entered the Vc. No overlap was evident in the radiations from the two sources. An unusual human case is presented suporting the sensory function of Vc since a lesion in this nucleus resulted in persistent contralateral paresthesia. On the other side, a discrete lesion in Vim caused no sensory disturbance.