Primary amyloidoma of the thoracic spine causing paraparesis.

A 52-year-old lady presented with progressive paraparesis. MRI revealed collapse of D9 vertebrae which was infiltrated by a low signal lesion both on T1 and T2. She underwent vertebrectomy and insertion of moss cage. The histology came back as amyloidoma. The presentation, investigation and management of primary amyloidoma of the spine is discussed along with a review of the literature.

Lumbar canal stenosis presenting with acute bilateral foot drop.

We present a case of bilateral foot drop of acute onset related to lumbar canal stenosis in the absence of an acute disc prolapse, either on imaging or at surgery. The clinical and radiological findings in this case are discussed. Possible mechanisms for this occurrence are discussed and the relevant literature is reviewed.

Depolarisation phenomena in traumatic and ischaemic brain injury.

1. Cortical spreading depression is a non-physiological global depolarisation of neurones and astrocytes that can be initiated with varying degrees of difficulty in the normally perfused cerebral cortex in the experimental laboratory. Induction is typically with electrical stimulation, needling of the cerebral cortex, or superfusion of isotonic or more concentrated potassium chloride solution. The phenomenon propagates across the cerebral cortex at a rate of 2-5 mm per minute, and is accompanied by marked but transient increases in cerebral blood flow, in local tissue oxygen tension, and most probably in metabolic rate. 2. Peri-infarct depolarisation is also a depolarisation event affecting neurones and glia, with an electrophysiological basis similar or identical to CSD, but occurring spontaneously in the ischaemic penumbra or boundary zone in focal cerebral cortical ischaemia. Most such events arise from the edge of the ischaemic core, and propagate throughout the penumbra, at a rate similar to that of cortical spreading depression. 3. Cortical spreading depression in the normally perfused cortex does not result in histological damage whereas peri-infarct depolarisations augment neuronal damage in the penumbra, and are believed by many authors to constitute an important, or the principal, mechanism by which electrophysiological penumbra progressively deteriorates, ultimately undergoing terminal depolarisation and thus recruitment into an expanded core lesion. 4. There is some experimental evidence to suggest that under some circumstances induction of episodes of cortical spreading depression can confer protection against subsequent ischaemic insults. 5. Although cortical spreading depression and peri-infarct depolarisations have been extensively studied in the experimental in vivo models, there is now clear evidence that depolarisations also occur and propagate in the human brain in areas surrounding a focus of traumatic contusion. 6. Whether such events in the injured human brain represent cortical spreading depression or peri-infarct depolarisation is unclear. However, invasive and probably non-invasive monitoring methods are available which may serve to distinguish which event has occurred. 7. Much further work will be needed to examine the relationship of depolarisation events in the injured brain with outcome from cerebral ischaemia or head injury, to examine the factors which influence the frequency of depolarisation events, and to determine which depolarisation events in the human brain augment the injury and should be prevented.

Posterior lumbar interbody fusion for revision disc surgery: review of 50 cases in which carbon fiber cages were implanted.

OBJECT: The authors undertook a study to assess the value of posterior lumbar interbody fusion (PLIF) in which carbon fiber cages (CFCs) were placed in patients undergoing revision disc surgery for symptoms suggesting neural compression with low-back pain. METHODS: The authors followed their first 50 patients for a maximum of 5 years and a minimum of 6 months after implantation of the CFCs. Patients in whom magnetic resonance (MR) imaging demonstrated "simple" recurrent herniation did not undergo PLIF. Surgery was performed in patients with symptoms of neural root compression, tension signs, and back pain with focal disc degeneration and nerve root distortion depicted on MR imaging compatible with clinical signs and symptoms. In 40 patients (80%) pedicle screws were not used. Clinical outcome was assessed using the Prolo Functional Economic Outcome Rating scale. Fusion outcome was assessed using an established classification. Symptoms in 46 patients (92%) improved after surgery, and given their outcomes, 45 (90%) would have undergone the same surgery again. Two thirds of patients experienced good or excellent outcomes (Prolo score > or = 8) at early and late follow up. There was no difference in clinical outcome between those in whom pedicle screws were and were not implanted (p = 0.83, Mann-Whitney U-test). The fusion rate at 2 years postsurgery was 95%. There were minimal complications, and no patients fared worse after surgery. No patient has undergone additional surgical treratment of the fused intervertebral space. CONCLUSIONS: In this difficult group of patients the aim remains to improve symptoms but not cure the disease. A high fusion rate is possible when using the CFCs. Clinical success depends on selecting patients in whom radiological and clinical criteria accord. Pedicle screws are not necessary if facet joints are preserved, and high fusion rates and clinical success are possible without them.

A cost-benefit evaluation of helicopter transfers to the Beaumont neurosurgical unit.

A retrospective analysis of all consecutive helicopter transfers to the Beaumont neurosurgical unit was performed over a two year period from January 1994 to December 1996. There were 55 transfers, 55% of which were for trauma patients. Sixty two per cent were intubated prior to transfer. The mean length of stay at the referring hospital prior to transfer was 12.25 hours (range 3-98 hours). Twenty five per cent underwent a neurosurgical operation within 2 hours of arrival at the unit. Seventy eight per cent of patients either made a full recovery or were left with mild to moderate disability. Whilst helicopters do not seem to result in a marked reduction in total transfer time compared with 'blue light' ambulances, they do result in a shorter time being spent in the unstable transfer environment and this, in turn, might be associated with improved patient outcome.

Cluster analysis of diffusion tensor magnetic resonance images in human head injury.

OBJECTIVE: Issues surrounding the nature of the edema associated with traumatic brain injury in humans, and its evolution in the acute phase, remain unresolved. This study aimed to characterize the topographical nature of the pathophysiological changes in human traumatic brain injury with diffusion tensor magnetic resonance imaging. METHODS: Multislice diffusion-weighted magnetic resonance imaging data were acquired from five patients undergoing elective ventilation for management of traumatic focal contusion or hematomas. The diffusion tensor and the T2-weighted intensity were then computed for every voxel in the image data set for each patient. The topographical distribution of abnormalities in the trace of the diffusion tensor and T2-weighted images were characterized by cluster analysis. RESULTS: In four patients with technically satisfactory data, a narrow band of tissue was observed in the periphery of focal lesions, which was characterized by selective reduction in the trace of the diffusion tensor, without any associated increase in the T2-weighted signal intensity. CONCLUSION: This change is interpreted as indicating either a partial redistribution of water from the extra- to intracellular compartment, or a reduction in the diffusivity of water in the intracellular or cytosolic environment. These diffusion and T2-weighted characteristics are also found in early ischemic change, hence, such regions may represent potentially salvageable tissue at risk of permanent damage. The study illustrates the advantage of using information contained within the diffusion tensor in addition to more conventional imaging sequences.

Cost-effectiveness analysis of end-stage renal disease treatments.

The cost-effectiveness of various end-stage renal disease (ESRD) treatments was compared using two different cost measures. The first measure, gross social costs, excluded output gains due to treatment, whereas the second measure, net social costs, included output gains from both market and nonmarket activities. The cost-effectiveness criterion was the cost-per-life year gained or the implicit value of a year of life. The lower the cost-per-life year gained, the more cost-effective the treatment was. Four ERSD treatments were evaluated over 20 years. Home dialysis and transplantation were more cost-effective than in-center dialysis, regardless of whether gross or net social costs were used. However, lower values were obtained in the case of net social costs reflecting a provision for output gains due to treatment. The use of net social costs also resulted in greater variations in costs-per-life year gained by age. Changes in survival probabilities affected the results for transplant patients and dialysis patients differently.