Hyperacute spinal subdural haematoma as a complication of lumbar spinal anaesthesia: MRI

We report two cases of hyperacute spinal subdural haematoma secondary to lumbar spinal anaesthesia, identified with MRI. Prompt diagnosis of this infrequent, potentially serious complication of spinal anaesthesia is essential, as early surgical evacuation may be needed. Suggestive MRI findings in this early phase include diffuse occupation filling of the spinal canal with poor delineation of the spinal cord on T1-weighted images, and a poorly-defined high-signal lesion with a low-signal rim on T2-weighted images. Received: 10 November 1998 Accepted: 6 April 1999     

Cavernous Haemangiomas of the Spinal Cord. A Review of 117 Cases

 The data of 48 studies (published between 1903 and 1996), presenting information of all together 107 patients (108 lesions) regarding pre-treatment clinical and radiological factors, treatment strategies, and the outcome, plus our own experience of nine patients were retrospectively re-analyzed. The prognostic influence of pre-treatment factors was estimated with the chi-square statistics. Clinical evaluation before/after treatment was performed using the Frankel scale. The average bleeding rate was obtained from the ratio of percentage of first bleeding events in the population to the mean age of the population.  There were 47 males and 69 females (aged from twelve to 88 years). Thirty nine percent of the lesions were found in the cervical, 54% in the thoracic (30% upper, 24% lower) and 7% in the lumbar cord. The peak age of presentation was in the fourth decade, the median duration of symptoms was 32 months. Clinical symptoms before treatment were progressive in all cases. Three patterns of clinical presentation could be identified: a) episodes of stepwise clinical deterioration (30%), b) slow progression of neurological decline (41%), c) acute onset with rapid or gradual decline over weeks or months (26%). 58% of the lesions showed clinical or radiological signs of haemorrhage. In 66% of surgical patients (91 efficiently documented cases), clinical improvement was achieved, 28% remained unchanged and 6% deteriorated. Whereas age, sex and lesion location had no influence on the results, duration of symptoms (<three years) correlated significantly to a better outcome (p<0.02).  Surgical management in symptomatic patients is recommended. Once clinical signs caused by the malformation have appeared, the patients tend to experience progressive neurological deterioration.     

Ondansetron versus placebo for the control of nausea and vomiting during Caesarean section under spinal anaesthesia

This prospective, randomised, placebo-controlled, double-blind study was performed to evaluate the effects of ondansetron on nausea and vomiting during elective Caesarean section under spinal anaesthesia. Seventy-four full-term parturients were studied. After umbilical-cord clamping, ondansetron 4 mg or 0.9% saline was injected intravenously and the study period continued for 2 h. The severity of nausea was graded from 0 = none to 10 = maximum, while that of vomiting was graded from single = once per min to continuous = multiple per min. The incidence of vomiting was lower following ondansetron (36%) compared with the control group (58%, p < 0.028). Neither the severity of vomiting nor the incidence of nausea was influenced by ondansetron. However, for those who experienced nausea, ondansetron reduced its severity (p = 0.05). We conclude that the intra-operative administration of 4 mg ondansetron intravenously during Caesarean section under spinal anaesthesia significantly reduces the incidence of vomiting and the severity of nausea.     

MRI findings in Hirayama’s disease: flexion-induced cervical myelopathy or intrinsic motor neuron disease?

Hirayama’s disease is a benign juvenile form of focal amyotrophy affecting the upper limbs. Previous studies have suggested that the disorder is a neck flexion induced cervical myelopathy. We report clinical and magnetic resonance imaging findings in nine patients with Hirayama’s disease. Cervical imaging of seven patients revealed spinal cord changes consisting of focal atrophy and foci of signal alterations. On neck flexion a forward movement and mild reduction in the anteroposterior diameter of the lower cervical cord against the vertebral bodies was noted in affected individuals as well as in five normal controls. In contrast to earlier reports, none of our patients showed complete obliteration of the posterior subarachnoid space. Measurement of the anteroposterior spinal cord diameter in each vertebral segment (C4–C7) revealed no significant differences in the degree of spinal cord flattening between the two groups. Furthermore, two of our patients had significant degenerative changes in the cervical spine (disc herniation, retrospondylosis) contralateral to the clinically affected side. These degenerative changes resulted in a marked cord compression on neck flexion but were not associated with ipsilateral clinical abnormalities or spinal cord alterations. Our results argue against a flexion-induced cervical myelopathy and support the view that Hirayama’s disease is an intrinsic motor neuron disease. Received: 15 March 1999 Received in revised form: 25 May 1999 Accepted: 1 June 1999     

Selective up-regulation of P- and R-type Ca2+ channels in rat embryo motoneurons by BDNF

Cultured spinal cord motoneurons from day 15 rat embryos (E15) represent a useful model to study Ca2+ channel diversities and their regulation by neurotrophins. Besides the previously identified L-, N- and P-type channels, E15 rat motoneurons also express high densities of R-type channels. We have previously shown that the P-type channel is nearly absent in 60% of these cells, while the R-type contributes to approximately 35% of the total current. Here, we show that chronic preincubation of cultured rat motoneurons with high concentrations (20-100 ng/mL) of brain-derived neurotrophic factor (BDNF) caused a selective up-regulation of the P- and R-type current density available after blocking N- and L-type channels, with no changes to cell membrane capacitance. N- and L-type channels were either not affected or slightly down-modulated by the neurotrophin. The onset of BDNF up-regulation of P/R-type currents had a half-time of 12 h and reached maximal values of approximately 80%. High concentrations of nerve growth factor (NGF; 50-100 ng/mL) had no effect on P/R currents, while BDNF action was prevented by the kinase inhibitor K252a and by the protein synthesis inhibitor anisomycin. These results suggest that chronic applications of BDNF selectively up-regulates the Ca2+ channel types which are most likely to be involved in the control of neurotransmitter release in mammalian neuromuscular junctions. The signal transduction mechanism is probably mediated by TrkB receptors and involves the synthesis of newly functionally active P- and R-type channels. Our data furnish a rationale for a number of recent observations in other laboratories, in which prolonged applications of neurotrophins were shown to potentiate the presynaptic response in developing synapses.     

CNS pattern of metabolic activity during tonic pain: evidence for modulation by beta-endorphin

CNS correlates of acute prolonged pain, and the effects of partial blockade of the central beta-endorphin system, were investigated by the quantitative 2-deoxyglucose technique in unanaesthetized, freely moving rats. Experiments were performed during the second, tonic phase of the behavioural response to a prolonged chemical noxious stimulus (s.c. injection of dilute formalin into a forepaw), or after minor tissue injury (s.c. saline injection). During formalin-induced pain, local glucose utilization rates in the CNS were bilaterally increased in the grey matter of the cervical spinal cord, in spinal white matter tracts and in several supraspinal structures, including portions of the medullary reticular formation, locus coeruleus, lateral parabrachial region, anterior pretectal nucleus, the medial, lateral and posterior thalamic regions, basal ganglia, and the parietal, cingulate, frontal, insular and orbital cortical areas. Pretreatment with anti-beta-endorphin antibodies, injected i.c.v., led to increased metabolism in the tegmental nuclei, locus coeruleus, hypothalamic and thalamic structures, putamen, nucleus accumbens, diagonal band nuclei and dentate gyrus, and in portions of the parietal, cingulate, insular, frontal and orbital cortex. In formalin-injected rats, pretreated with anti-beta-endorphin, behavioural changes indicative of hyperalgesia (increased licking response) were found, which were paralleled by a significant enhancement of functional activity in the anterior pretectal nucleus and in thalamo-cortical systems. A positive correlation was found between the duration of the licking response and metabolic activity of several forebrain regions. These results provide a map of the CNS pattern of metabolic activity during tonic somatic pain, and demonstrate a modulatory role for beta-endorphin in central networks that process somatosensory inputs.     

Morphological analysis of the cervical spinal canal,dural tube and spinal cord in normal individuals using CT myelography

To verify the conventional concept of developmental stenosis of the cervical spinal canal, we performed a morphological analysis of the relations of the cervical spinal canal, dural tube and spinal cord in normal individuals. The sagittal diameter, area and circularity of the three structures, and the dispersion of each parameter, were examined on axial sections of CT myelograms of 36 normal subjects. The spinal canal was narrowest at C4, followed by C5, while the spinal cord was largest at C4/5. The area and circularity of the cervical spinal cord were not significantly correlated with any parameter of the spinal canal nor with the sagittal diameter and area of the dural tube at any level examined, and the spinal cord showed less individual variation than the bony canal. Compression of the spinal cord might be expected whenever the sagittal diameter of the spinal canal is below the lower limit of normal, that is about 12 mm on plain radiographs. Thus, we concluded that the concept of developmental stenosis of the cervical spinal canal was reasonable and acceptable.     

Transpedicular reduction and stabilization for postlaminectomy lumbar instability

Summary This study retrospectively reviewed the outcomes of 17 patients with postlaminectomy lumbar instability treated by transpedicular reduction and stabilization. The criteria of instability were defined strictly by both the clinical symptom of instability catch and the radiological findings that fulfilled Nachemson's criteria. Low back pain and/or sciatica that interfered largely with the patients' work or quality of life were the indications for this treatrment. All the operations were performed by one surgeon with the same spinal instrumentation system — AO internal fixator. The follow-up period was between 16 and 36 months (mean 24 months).Face to face questionnaire revealed that this treatment modality is encouraging. Fourteen patients (82%) had complete or nearly complete relief from all the pre-operative symptoms. Two (12%) had partial relief of the symptoms that required a subsequent discectomy or wider laminectomy. Only one case (6%) with osteoporosis remained unchanged after the operation. On the follow-up radiographs, sixteen patients (94%) showed good alignment and solid arthrodesis of the treated motion segment. These radiological findings correlated quite well with the absence of the clinical symptom of instability catch.A common, but acceptable, complication found in this series was a variable degree of low back stiffness secondary to the instrumentation. Fracture of the screw was found in one patient and pull out of the screw was found in another patient. However, they did not elicit detectable symptoms.Osteoporosis, concomitant disc herniation and persistent spinal stenosis at/or adjacent to the operated level were the three main factors that may contribute to unsatisfactory results secondary to this treatment. These problems remain to be resolved in thp future.     

Primary spinal column sarcomas

Summary Five cases of primary spinal column sarcomas are presented. Sarcomas primarily originating from paravertebral soft tissues were excluded. Patients' age ranged from 1 to 14 years (mean 8.4 years). The male: female ratio was 23. Two patients had Ewing's sarcoma (ES) originating from L5-S1 and L4-5 pedicles, respectively; two patients had mesenchymal chondrosarcoma (MCS) originating from L1-2 pedicles and L5 body, respectively; and one patient had osteogenic sarcoma (OS) of C4 body. All patients clinically presented with pain and progressive weakness of the extremities. The time that elapsed between the onset of symptoms and diagnoses ranged from one to five months. All cases were treated with chemotherapy, radiotherapy and subtotal tumour resection with spinal canal decompression. Two cases received posterior spinal fusion operations. Three patients were alive 10 to 98 months following diagnosis. Only the case with ES of L5-S1 pedicles was in complete remission and off therapy at the 98th postoperative month. The two MCS cases were in partial remission, and were receiving chemoterapy at the time of analysis. These tumours caused similar clinical findings and prognoses, and required combined treatment, which consisted of surgery, radiotherapy and chemotherapy; histologically three different types of malignant tumours are presented in the same category. We preferred surgical decompression and stabilization procedures especially for neurologically symptomatic patients, even if they had extensive tumours with high grades. By spinal canal decompression and stabilisation, we did not intend to cure the disease; however, we intended to provide neurological improvement, spinal stabilisation, improved quality of life, early mobilisation of the patient, and cytoreduction by means of surgical tumour ablation, which could render the chemotherapy more effective.     

Spinal accessory nerve palsy due to neurovascular compression. Report of a case diagnosed by magnetic resonance imaging and magnetic resonance angiography

The case of a young patient with left accessory nerve paralysis is reported. He had slight tilting of the head to the right side, developed over a period of about 6 months. On neurological examination hypotrophy of the left sternocleidomastoid and trapezius muscles was observed. MRI and MR-angiography imaged the presence of a neurovascular compression between the medulla oblungata, at the level of the nerve entry zone, and a vessel loop of an elongated left vertebral artery. In spite of the absence of a surgical demonstration it is our opinion that the neurovascular conflict is the cause of the accessory nerve palsy.