Biomedical subjects
Publications and source records attributed to M R MacFarlane.
We report a case of malignant intraventricular meningioma with CSF drop metastases and an implantation metastatic subgaleal nodule in a 53-year-old woman. Malignant intraventricular meningiomas are rare with only seven cases being reported in the literature. These tumours can be very aggressive and one should consider immediate postoperative radiotherapy.
BACKGROUND: Recent evidence has highlighted the importance of the neurosurgeon in the management of secretory pituitary tumours, but most reports are from major centres. AIMS: To audit the surgical outcome of patients with acromegaly and Cushing's disease treated in a small centre (Christchurch, New Zealand) by a dedicated neurosurgeon with an interest in pituitary disease, and follow-up through an outpatient Department of Endocrinology. METHODS: All cases of acromegaly and Cushing's disease admitted for surgery in Christchurch Hospital between 1984 and 2000 were audited. Data concerning preoperative findings, surgical remission rate, complications and follow-up were obtained from 44 patients (28 acromegaly, 16 Cushing's disease). RESULTS: Of the 28 acromegalic patients, 14 patients (50%) had a mean growth hormone level <2.5 micro g/L within the first postoperative week. Of the 15 Cushing's disease patients in whom the pituitary fossa was explored, 13 patients (87%) entered a postoperative remission, defined as an 08.00 h cortisol <200 nmol/L (normal range 250-800 nmol/L). No perioperative deaths occurred. Two of the 43 patients (4.7%) developed permanent diabetes insipidus, while eight of the 28 patients who were operated on for acromegaly (29%) eventually required some replacement treatment for hypopituitarism during follow-up (one presented with apoplexy and seven were treated with postoperative radiotherapy). CONCLUSION: In a small centre with a dedicated pituitary surgeon, operative remission rates approach those obtained in larger, more specialized centres. However, given New Zealand's small, but geographically spread population, consideration should be given to establishing one or two units for the surgical management of secretory pituitary adenomas.
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OBJECTIVE: Diastematomyelia is a form of spinal dysraphia involving a sagittal cleft in the spinal cord with splaying of the posterior spinal elements. This may be an isolated abnormality or in association with more serious dysraphic conditions. In isolated diastematomyelia, the skin is intact and the prognosis excellent. This study aimed to determine the usefulness of prenatal sonography in diagnosing diastematomyelia and in predicting the isolated form. SUBJECTS AND METHODS: The usefulness of the sonographic findings of an extra posterior echogenic focus between the fetal spinal laminae and splaying of the posterior elements for the prenatal sonographic diagnosis of diastematomyelia was assessed in five cases prospectively and in one case retrospectively. The posterior echogenic focus was first seen on prenatal sonograms at a mean age of 19 weeks' gestation (range, 18-20 weeks). The final diagnosis of diastematomyelia was made at autopsy in two cases (one with an associated meningocele), at postmortem radiography in one, at surgery in one, and at CT myelography in two. Postnatal spinal sonograms were obtained in each case. The ability to detect fetal spinal widening on prenatal sonograms was compared with the postnatal radiologic appearance on spinal plain film radiographs. RESULTS: Diastematomyelia was confirmed in all five cases where the extra posterior echogenic focus was seen at prenatal sonography. The double spinal cord was within a single dural sheath in three cases, with no bony bar present. A double dural sheath with a bony bar was noted in a fourth case. In the fifth case, a bony bar was seen on a postmortem spinal X-ray, but a double dural sheath could not be confirmed because an autopsy was not performed. In the case where diastematomyelia was not suspected on prenatal sonograms, the dural sheath was single and no bony bar was present. Splaying of the posterior elements was seen on postnatal radiographs in all cases but was suspected in only four on prenatal sonograms. Prenatal sonography accurately predicted isolated diastematomyelia in four cases and complicated diastematomyelia in one case. The one case missed prenatally was of isolated diastematomyelia. CONCLUSION: A diagnosis of diastematomyelia can be made if an extra posterior echogenic focus is seen on prenatal sonography. Splaying of the posterior elements of the fetal spine is frequently present. The pregnancy should be managed differently depending on whether the diastematomyelia is isolated, with the skin intact, or is in association with more serious neural tube defects. This distinction is possible prenatally.
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Titanium is widely used as an implant material. This report describes its use for cranioplasty and malar defects and the technique used to fashion these prostheses in a centre which does not have the facility for producing computer-generated full-size craniofacial models. The use of these prostheses has produced very satisfactory results with minimal morbidity and no complications.
The role of the brain opioid system in the control of hypothalamic-pituitary-adrenal activity was studied in 10 conscious sheep with an indwelling cannula in a cerebral lateral ventricle. On separate days, sheep received infusions of artificial CSF (control) and the opiate antagonist, naloxone (100 micrograms/hr) before and during acute moderate hemorrhage (15 ml/kg over 10 min). Infusion of naloxone before hemorrhage raised plasma ACTH and resulted in a significant increase in cortisol compared to the control infusion. In contrast, ACTH and cortisol responses to hemorrhage tended to be blunted by central naloxone infusion. The responses of vasopressin, aldosterone and the catecholamines remained unaffected by naloxone. The fall in blood pressure and the rise in heart rate accompanying hemorrhage were likewise unaltered. These results suggest that brain opioid peptides have an inhibitory effect on basal ACTH secretion but do not play a major role in modulating the hemodynamic or pituitary-adrenal responses to acute moderate hemorrhage in conscious sheep.
Spinal cord compression from a metastasizing burn scar cancer has not previously been reported. A patient with rapidly progressive paraparesis associated with vertebral collapse and an extradural soft tissue mass of undetermined origin is presented. The clinical history, radiological diagnosis, and histological features of cicatrial carcinoma are discussed along with a brief review of the relevant literature.
The role of the brain renin-angiotensin system in mediating the peripheral hormone response to acute hemorrhagic stress (15 ml/kg over 10 min) was studied in 6 sheep during an intracerebroventricular infusion (2.8 micrograms/min) of the angiotensin-converting enzyme inhibitor, captopril. When compared with control experiments the plasma ACTH and vasopressin (AVP) response to hemorrhage was markedly reduced and delayed during icv captopril, which did not affect the response of plasma angiotensin II (AII). These results suggest that the normal and rapid response in ACTH and AVP secretion accompanying hemorrhagic stress is dependent on increased brain production of AII.
A Brindley-Finetech sacral anterior root stimulator has been placed intradurally in the spinal canal around the S2, 3, 4 nerve roots in six paraplegics at the Burwood Spinal Injuries Unit, Christchurch, New Zealand. The apparatus developed by Professor G. S. Brindley and the Medical Research Council in London, UK, has proved very useful in driving micturition, in achieving a dry device-free interval between electromicturitions, in reducing the incidence of urinary tract infections, and in some males in achieving a sustained erection. The clinical results are presented with a urodynamic analysis of the outcome.
Acute moderate hemorrhage (15 ml/kg withdrawn over 10 min) was used to study stress hormone changes in blood and cerebrospinal fluid (CSF) of conscious sheep with chronic indwelling intracerebroventricular catheters. Mean plasma arginine vasopressin (AVP) and ACTH rose 150- and 14-fold, respectively, above basal values to peak levels at 20 min after onset of hemorrhage. A smaller (4- to 5-fold) rise occurred in plasma angiotensin II (AII) to peak levels at 10 min. The corticosteroid response (cortisol and aldosterone) occurred later (peak at 45 min) and was consistent with the dependence of these steroids on plasma ACTH and AII changes. Increases in plasma epinephrine and norepinephrine were small and transient. Compared to changes in plasma, changes in CSF hormone levels after hemorrhage were small and independent of plasma concentrations. Mean CSF AVP increased to peak levels at 15 min whereas rises in CSF ACTH, AII-like immunoreactivity, and cortisol were slower and delayed in comparison with the patterns observed in plasma. Despite evidence of increased sympathetic activity, and rise in plasma catecholamines, CSF epinephrine fell after hemorrhage and CSF norepinephrine did not change. These results show that in conscious sheep rapid and major increases in plasma AVP, ACTH, and AII follow acute moderate hemorrhage. Concomitant changes in CSF hormone levels are small and delayed. With the possible exception of AVP it appears unlikely that the acute systemic hormone response to hemorrhage is determined by hormone changes in CSF.
Twenty-eight patients with aneurysms of the posterior circulation were managed by direct operations, 53.6% of these being done within 14 days of a subarachnoid hemorrhage. Transvenous cardiac pacing was used in 4 of the 13 patients with aneurysms of the basilar bifurcation in order to produce a short period of profound hypotension while final dissection and clip application was performed. There were nine patients with posterior-inferior cerebellar artery/vertebral-junction aneurysms, the only one dying having a large aneurysm. The operative technique used in the majority of the 13 patients with basilar bifurcation aneurysms involved subtotal temporal lobectomy, and the operative exposure so obtained was excellent. Five patients died, one of whom rebled from an aneurysm of the basilar artery origin that could only be wrapped, the total mortality being 17.9%. Seventeen (74%) of the 23 survivors were assessed as showing good results; 5 (22%) as showing fair results, and only 1 (4%) as showing a poor result.
A microsucker for use in microneurosurgery is described. It has a small-caliber tip, is of light weight, and has the special feature of infinitely variable suction from zero to maximum pressure, achieved by thumb movement only.