Biomedical subjects
Publications and source records attributed to R Braakman.
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Two cases of traumatic bilateral locked facets in the thoracic spine are reported. Both patients had only minor neurological signs. They both made a full neurological recovery after surgical reduction of the locked facets. Bilateral locked facets are very uncommon in the thoracic spine. The diagnosis should be considered in any patient with a fracture-dislocation of the thoracic spine. In these cases additional lateral tomographs are required. Early open reduction of bilateral locked facets and internal fixation are mandatory.
This study was performed to characterise a vascular bed in terms of pressure-flow relationships. Steady state and instantaneous relationships were obtained in the flow perfused isolated femoral beds of six mongrel dogs. The steady state pressure-flow relations were obtained by applying a series of stepwise changes of flow in random order. The relations were found to be straight and to have a zero-flow pressure intercept (P0). The slope of this relation is the differential resistance (Rd). On each steady state flow level a ramp-flow was superimposed. The pressure response was measured between 1.5 and 5 s after the start of the ramp-flow, to exclude compliance effects and (auto) regulatory effects, respectively. In this way instantaneous pressure-flow relations were obtained, the slope of this relation is the instantaneous resistance (Ri). The instantaneous resistance expresses the true physical resistance value at a working point of the steady state pressure-flow relation before the bed has performed its (auto)regulatory adaptation after a change in flow. Instantaneous resistance therefore characterises the vascular state that exists at that particular working point. After this particular vascular state has been modified by (auto)-regulation the steady state pressure-flow relation is reached again. Instantaneous resistance increases with increasing flow thereby approximating the value of the differential resistance. At the same flow a vasodilator decreases and a vasoconstrictor increases instantaneous resistance. The gain (G) of the system, that characterises the (auto)regulatory capability, was calculated as G = 1--Ri/Rd and was found to decrease with increasing flow. The (partial) reflection of travelling waves depends on both the characteristic impedance (Zc) and the instantaneous resistance rather than on differential or peripheral resistance. Furthermore it is the product of the instantaneous resistance (Ri) and vascular compliance (C) that determines the time constant of a vascular bed.
Ten consecutive patients with arachnoid cysts in the middle cranial fossa, diagnosed by CT, were studied. They were divided into three clinical groups: (1) four patients with progressive symptoms caused by secondary bleeding, (2) five patients with non-progressive symptoms of headache or epilepsy, and (3) one asymptomatic patient. The nine symptomatic patients were operated upon and eight showed clinical improvement. Measurements of the CT scans revealed equal brain volumes on the affected and normal sides, refuting the hypothesis that the cyst is caused by agenesis of the temporal lobe. The hemicranium on the affected side was larger, accommodating both the cyst and a normal brain volume. The progressive symptoms after bleeding were caused by brain shift and increased CSF pressure. The cause of the non-progressive symptoms has not yet been established: two mechanisms are suggested: (1) expansion of the cyst accompanied by compression of surrounding structures, and (2) disturbed CSF dynamics without increased intracystic pressure. Removal of the membranes of the cyst with an opening to the basal cisterns should resolve both problems. After surgery a residual cyst may remain.
This study describes inter-observer agreement between physicians and consistency of one observer on repeated scoring in the assessment of outcome 6 to 12 months after severe head injury. Observer agreement is expressed by Kappa, taking chance agreement into account. The study was conducted in "live" and "non-live" situations, using five- and eight-category outcome scales. Kappa values were considerably higher when the five-category scale was used. However, even with the five-category scale, disagreement was considerable, and the results indicate that accurate predictions of the quality of survival will be difficult to attain. Observer agreement should be taken into account in prognosis studies, and when different therapeutic regimens are evaluated on the basis of outcome.
A prospective double-blind clinical trial was performed on 161 patients to determine the effectiveness of high-dose steroid therapy in patients admitted comatose after a non-missile-related head injury. Patients were randomized into a high-dose dexamethasone phosphate group and a placebo group. The initial dose of 100 mg of dexamethasone was administered within 6 hours of the accident. For statistical analysis, a sequential test was chosen, using survival at 1 month as a basic criterion of effectiveness. No significant difference was found in the 1-month survival rate or in the distribution of outcome after 6 months, either within the group as a whole, or in subgroups with varying severity of brain damage on admission. The authors conclude that dexamethasone in high doses has no statistically significant effect on morbidity or mortality in head-injured patients who are comatose on admission.
A comparison is made between the outcome distributions of two Dutch series of patients with severe head injuries. Both series are taken from the same study and cover the same period (1974 to 1977). There is a large difference in survival rate between the series: 45% versus 63%. The authors present a possible method for assessing the influence of differences in initial severity of injury on outcome. It is estimated that, of the 18% difference in survival rate, 10.5% is due to differences in severity of injury on admission. The remaining 7.5% difference in survival rate is not explained, but may have been caused by unmeasured variations in the initial determination of severity of injury or by differences in effectiveness of management. The higher survival rate was achieved at the center with the more conservative management regimen. An evaluation of recent literature suggests that reports that do not find aspects of "aggressive" management beneficial are more reliable in comparing series than are those that claim improved outcome after aggressive therapy.
In a series of 121 comatose head-injured patients, computerized tomography (CT) scans were obtained at various intervals after onset of coma. The scans were classified without knowledge of previous scans or of the patient's clinical state, and predictions as to outcome at 1 year were made based on clinical features and CT findings. The state of the basal cisterns as seen on CT scans proved to be a very powerful prognosticator. Subsets of features with the greatest prognostic weight were selected systematically for CT features, clinical features, and for a combination of CT and clinical features. With these features, probability statements were made about death or survival at 1 year. The quality of the predictions was established by comparing them with actual outcome. The percentage of accurate predictions was markedly higher with a combination of clinical and CT features than with clinical or CT features alone.
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Thirty-seven patients treated for os odontoideum are reviewed. In 20 patients the treatment was conservative and in 17 consisted of occipitocervical or atlanto-axial fusion. Two patients died after the operation and another, who lived abroad, was lost to follow-up. The remaining 34 patients were followed up for an average of eight years: 19 improved, 14 were unchanged and one deteriorated. In the subgroup of 25 patients without cord signs, there were no significant differences between the two modes of treatment. Analysis of the radiological features of the upper cervical spine in 21 patients revealed a minimal sagittal diameter of less than 13 millimetres to be associated with a high risk of permanent cord damage. There was no correlation with the degree of instability per se. On the basis of this analysis, guidelines are suggested for the management of patients with an os odontoideum.
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The literature of the last decade concerning the management and outlook of paraplegia has been focused on traumatic or other 'benign' causes. This paper describes a series of 74 patients with paraplegia due to malignant disease, one of the other most common causes of paraplegia.
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Difficulties in establishing the value of certain treatments for head injury are reviewed. An analysis of 1000 severely head injured patients, managed by varying methods in three different countries, showed that certain treatments were more often used in the most severely injured patients. Even when the severity of injury was taken account of, it appeared that the use of steroids and tracheostomy did not affect outcome; but that patients undergoing mechanical ventilation had outcomes which were worse than expected. The value of treatments proposed for severe head injury needs rigorous scrutiny.
Ninety-seven of a consecutive series of 225 head-injured patients who were in coma for at least 6 hours survived for 12 months or more. Seventy-nine underwent computed tomography (CT) 1 to 4 years after the injury. Ct findings such as infratentorial and focal and diffuse supratentorial atrophy were correlated with overall social outcome, persistent neurological deficit, operations, and prognostic features. Coma lasting longer than 24 hours, ataxia, and severe disability show a high correlation with infratentorial atrophy, alone or in combination with supratentorial atrophy. Patients who came out of coma within 24 hours after injury and those who ultimately recovered well usually had a normal CT scan or focal supratentorial atrophy only. Most patients who had undergone operation for space-occupying extra- or intradural hematomas or contusions had focal atrophy on the operated side.
In this study small sets of clinical features were identified that, when combined, yield high quality predictions of long term outcome. The study is based on a series of 305 consecutive head-injured Dutch patients, all of whom had been in coma for at least 6 hours. The overall social outcome was assessed after 6 months using the Glasgow outcome scale. Predictions of outcome were made by assigning probabilities to each possible outcome category. The prognostically most promising features recorded during the early post-traumatic course were identified, and powerful combinations of prognostic features were selected on admission and 1, 3, 7, 14, and 28 days after the start of coma by an appropriate statistical method. At each time point, optimal prediction required sets of only three to five features, typically including age in decades, depth and duration of coma as assessed by the Glasgow coma scale, pupil reactivity to light, and spontaneous and reflex eye movements. The method described allows bedside predictions in individual patients and provides a tool for comparing the severity of injury between series of patients.
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