Biomedical subjects
Publications and source records attributed to G Blaauw.
A patient is reported with unilateral intermittent pulsating eye caused by the combination of an orbital encephalocele and hydrocephalus, thirty four years after a head injury. Treatment of the hydrocephalus resulted in disappearance of the eye pulsations and encephalocele, as well as in improvement of the gait.
Visual function, endocrinological status, and radiological outcome are reported in 31 patients harboring a cystic craniopharyngioma, who underwent 35 intracavitary brachytherapy procedures with yttrium-90. In 26 of these patients intracavitary brachytherapy was the primary treatment. The follow-up period ranged from 2 to 80 months (41 +/- 22 months, mean +/- standard deviation). Five patients died from tumor-related causes. Endocrine recovery was modest. Prior to brachytherapy, visual acuity was diminished in 38 eyes and field defects were present in 46. Funduscopy before treatment revealed optic atrophy in 47% of the eyes. Visual acuity improved in 29% of the eyes studied, remained stable in 13%, and deteriorated in 58%. Visual field defects improved in 28% of the eyes studied, remained stable in 20%, and deteriorated in 52%. The possible causes for deterioration in visual function are discussed. Complete resolution of 10 cysts was noted. In 12 patients the size of the cyst decreased; however, in three of these patients new cyst formation took place. The cyst size stabilized in six cases and increased in three. Although there is still a substantial degree of visual function deterioration following intracavitary brachytherapy, morbidity is otherwise low, making this treatment modality a reasonable alternative to craniotomy.
A visual, a computer-assisted and a trigonometric method for obtaining coordinates for stereotaxis are compared. Each method had its own deficiencies and produced comparable results.
Pulsatile growth hormone secretion patterns were studied in relation to luteinizing hormone and estradiol release in 33 healthy (pre)pubertal girls. Plasma GH was determined every 10 min, plasma LH and E2 every hour. Night-time GH release was always higher than daytime GH release. During daytime, all GH secretion parameters, except for the basal GH level, increased significantly from the prepubertal stage to stage B4 before (m-) the menarche (p = 0.05) and decreased thereafter (p = 0.05). During night-time, mean GH level and the fraction of GH in pulses also tended to increase from stage B1 to stage B4m-. The number of high pulses (greater than 8 micrograms/l) during day and night together tended to increase until stage B4m- and decreased after the menarche (p = 0.05). Height velocity did not correlate with the number of high pulses (Kendall tau = 0.14, p = 0.14). From stage B1 to B4m- high correlations were observed between E2 levels and GH secretion parameters, particularly during the day (tau = 0.59-0.71, p less than or equal to 0.01). The correlations between LH levels and GH secretion were high as well (tau = 0.50-0.81, p less than or equal to 0.01), but equal during day and night. It is concluded that during puberty 1. spontaneous GH release in girls increases 2-3 fold until the menarche and decreases thereafter, primarily as the result of an increasing and decreasing GH pulse amplitude; 2. diurnally increasing estradiol levels correlated with increasing GH secretion.
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An immunohistochemical study was performed on three meningeal haemangiopericytomas and four cerebellar haemangioblastomas (paraffin embedded) in an attempt to elucidate the uncertain histogenesis of these tumours. The tumour cells of all meningeal haemangiopericytomas show no expression of alpha-smooth muscle actin and, thus, no immunohistochemical proof of their true pericytic nature can be obtained. The stromal cells of cerebellar haemangioblastomas show foci of positive staining for S-100 protein, neuron-specific enolase and synaptophysin, thereby clearly indicating their neuroectodermal origin. These results allow the conclusion that the present nomenclature of these tumours is at least arguable and probably incorrect.
The advantages of computed tomography-guided preoperative localization of brain lesions are illustrated in four cases of solitary tuberculoma and in one case of tuberculous abscess of both the cerebrum and the cerebellum. The role of stereotactic diagnostic techniques is emphasized. The clinical presentation and the computed tomography findings in these patients were equivalent to those from glial or metastatic tumors. Synchronous pulmonary tuberculosis was not present in these patients, but in three patients there was metachronous tuberculosis. Tuberculous meningitis had not developed in any of the patients.
Pulsatile growth hormone secretion patterns were studied in relation to LH and testosterone release in 30 healthy prepubertal boys and 2 adult men. Plasma GH was measured every 10 min, plasma LH and testosterone every hour. Night-time GH secretion parameters were 2-3 times higher than daytime values. During daytime, mean GH level and the fraction of GH in pulses increased from Tanner stage G2 to G4 (p = 0.01); during night-time these parameters increased as well (p less than or equal to 0.1) and decreased from stage G5 to adulthood (p = 0.05). GH pulse number did not increase; the number of high-amplitude (greater than 8 micrograms/l pulses, however, increased from stage G2 to G4 (p = 0.05) during the day. Height velocity correlated with their number of high pulses during day and night (tau = 0.39, p less than 0.003). From stage G2 to G4 significant correlations were observed between nocturnal testosterone levels and GH secretion parameters (tau = 0.53-0.57), in contrast to nocturnal LH levels. It is concluded that during puberty 1. GH secretion increases as a result of an increased pulse amplitude; 2. there is no consistent correlation between GH and LH levels; 3. increasing nocturnal testosterone levels are correlated with the increasing GH secretion; therefore GnRH does not seem to influence GH secretion directly, but an indirect effect via testosterone is more conceivable, and 4. height velocity is correlated with the number of high GH pulses.
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In 492 patients with a lumbosacral radicular syndrome caused by a lumbar intervertebral disc herniation or by a stenosis of the lumbar spinal canal, the situation 1 year after a root decompressing operation was compared with the situation before surgery. About 75% of the patients reported satisfactory improvement, while about 10% were not satisfied. The judgement of the physicians is somewhat more favourable: 80% and 5%, respectively. The best results are obtained in patients in whom the preoperative diagnosis of lumbar disc herniation is highly probable; the worst results are obtained in patients undergoing a second operation. Back pain, sometimes serious, persists after surgery in about 50% of the patients. Such persistent back pain occurs most frequently in patients with a lumbar canal stenosis; one-third even mention a postoperative increase in back pain. About 50% of the patients who were on sick leave before operation resumed work afterwards.
Results of neurological assessment one year after surgical treatment of herniated lumbar intervertebral disc and lumbar stenosis are reported in 443 patients. Follow-up was performed during one year after operation. Preoperatively, surgeons found motor loss more frequently than patients, (28 and 12% respectively) and, postoperatively, motor loss was still present in 25% and 24%, respectively, of these cases. The operation had caused motor loss in 5% and aggravated motor loss in 3%. Sensibility was reported as abnormal one year after surgery by both patients and surgeons in one-third of the cases. Sensory loss, considered by the patient to have been caused or aggravated by the operation, occurred in 15% of the cases and in 12% of these the surgeons agreed. Preoperatively, unilaterally diminished knee and Achilles tendon reflexes were found in 9% and 42% respectively; one year after surgery, these had recovered in 65% and 57%, respectively. Surgery caused or aggravated unilaterally diminished knee or ankle jerks in 3% and 10%, respectively.
In four men and in one woman we found an intracranial local tuberculous infection (4 tuberculomas and 1 tuberculous abscess) in the period 1982-1988. Clinical presentation and computer tomography do not allow discrimination of intracranial tuberculomas from other space-occupying lesions. The value of the stereotactic biopsy for the diagnosis is emphasized and some characteristics of this intracranial process are discussed.
Some of the problems and dangers inherent to stereotaxis are discussed in a series of 243 procedures. Neurological deterioration, either due to haemorrhage or to traumatic oedema, was rare. One fatal accident occurred. Infections were not present although the patient's head was not shaved. Provided he can manipulate the proper instruments accurately stereotaxis can nowadays be performed by any surgeon who can make a burr hole and perform simple arithmetic calculations. This procedure can be considered to lie within the scope of any neurosurgeon.
A chondroblastoma within the temporal bone in a 16-year-old boy is reported. The tumor recurred after intracapsular resection and curettage. After reoperation, radiotherapy was performed. The data from 137 cases of chondroblastoma are summarized.
Results of neurological assessment 1 year following surgical treatment of herniated lumbar intervertebral discs and lumbar stenosis are reported in 443 patients. The data were collected using separate series of questionnaires to be completed by the patient and the surgeon. Preoperatively, motor loss was reported by 12% of patients, while surgeons found motor weakness in 28%. Postoperative motor loss was still present in 24% and 25% of these cases, respectively; the operation had caused or aggravated motor loss in 5% and 3% of cases, respectively. Sensory phenomena were reported by 53% of the patients, while surgeons found sensory loss in 45%. Sensation was reported as abnormal 1 year after surgery both by patients and by surgeons in one-third of these cases. Sensory loss, considered by the patient to be caused or aggravated by operation, occurred in 15% of cases and in 12% of cases the surgeons agreed. Preoperatively, unilaterally diminished knee and Achilles tendon reflexes were found in 9% and 42%, respectively; at 1 year after surgery, these had recovered in 65% and 57% of cases, respectively. Surgery caused or aggravated unilaterally diminished knee or ankle jerks in 3% and 10% of cases, respectively.
The value of computed tomography (CT) and myelography as single investigations in the diagnostic evaluation of patients with radiating leg pain probably due to lumbar disk herniation (LDH) has been adequately demonstrated. However, the extent to which CT can replace myelography and the conditions in which the examinations should be combined and in which order are still uncertain. Results of CT scans and myelograms from 461 patients with symptoms of lumbar root compression, probably due to LDH, were evaluated and compared with surgical results, if available. The sensitivity of myelography exceeded that of CT (82% vs. 73%), but its specificity was lower (67% vs. 77%). The positive predictive value of myelography only slightly differed from that of CT (93% vs. 94%). These results were used to establish a sequential diagnostic workup for patients with radiating leg pain. If, in this population with a high prior probability for surgery, CT had been the investigation of first choice in patients suspected of having LDH, the number of myelographic procedures performed could have been reduced by two-thirds.
The effect of transsphenoidal hypophysectomy is presented in 60 patients with visual impairment due to a pituitary adenoma, derived from a total series of 194 patients. The preoperative visual acuity and visual fields were compared with those one year after operation. The visual field loss was estimated using a semi-quantitative method. Seventy-two eyes had diminished visual acuity, and this improved in 45 eyes (63%). Visual field loss was present in 102 eyes and this improved in 71 eyes (70%). Improvement of either visual acuity and/or visual field was found in 84 eyes (78%). In 16 patients (27%) vision became normal after operation. Improvement of the visual acuity was usually accompanied by an improvement in the visual fields.