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Biomedical subjects

J Klekamp

Publications and source records attributed to J Klekamp.

35 records · Page 2Linked to original sources
PubMed1996

The surgical treatment of Chiari I malformation.

A retrospective study was undertaken on 133 patients with a Chiari I malformation treated within the last 16 years at the Departments of Neurosurgery at the Nordstadt Hospital Hannover, Germany, and the University of California, Los Angeles, U.S.A. Ninety-seven patients presented with symptoms related to accompanying syringomyelia and 4 with associated syringobulbia. They underwent 149 surgical procedures and were followed for a mean of 39 +/- 52 months. A decompression at the foramen magnum was performed in 124 patients, while 22 of those with syringomyelia were treated by shunting (7 syringosubarachnoid shunts, 15 syringoperitoneal or -pleural shunts), and 3 by ventriculoperitoneal shunts for hydrocephalus. Except for ventriculoperitoneal shunting, at least a short-term decrease in size of an associated syrinx was observed for all procedures in the majority of cases. However, no long-term benefit was observed for syrinx shunting operations. The best clinical long-term results were obtained with decompression of the foramen magnum in patients with (86% free of a clinical recurrence) and without syringomyelia (77% free of a clinical recurrence). We advise against syrinx shunting, a large craniectomy, and obex plugging which are associated with higher recurrence rates. Instead, surgery should consist of a small craniectomy, opening of the dura, archnoid dissection to establish normal cerebrospinal fluid (CSF) outflow from the 4th ventricle, and a fascia lata dural graft.

Adult↗
PubMed1996

Surgical results for meningiomas of the craniocervical junction.

OBJECTIVE: We have undertaken a retrospective analysis of 38 patients who were operated on for 40 meningiomas of the craniocervical junction between September 1977 and August 1995 to determine which factors influenced resectability, complications, and postoperative outcomes. METHODS: Radiological examinations, clinical data, and operation notes were evaluated, and additional follow-up information was obtained from outpatient examinations, telephone calls, and questionnaires. RESULTS: Four groups could be distinguished according to dural attachment as follows: 1) 15 spinocranial meningiomas originated from the spinal canal and extended intracranially; 25 craniocervical meningiomas of intracranial origin were divided into 2) meningiomas of the lower clivus (10 patients with 11 tumors), 3) lateral meningiomas (11 patients with 12 tumors), and 4) posterior meningiomas (2 patients). Standard midline or lateral suboccipital approaches with opening of the foramen magnum and laminectomy of the involved cervical segments were sufficient for the great majority of tumors. In seven instances only, drilling the posterior third of an occipital condyle was needed. Twelve of 15 spinocranial meningiomas and 13 of 25 craniocervical meningiomas could be removed totally. One patient underwent ventriculoperitoneal shunting only. With a rate of 63% of totally removed and 30% of subtotally removed meningiomas in this region, we observed clinical recurrences for two patients only. Complications were encountered in 30% of patients, predominantly with recurrent and/or infiltrative or en plaque meningiomas. Whereas motor weakness and gait ataxia tended to improve postoperatively, cranial nerve deficits usually remained unaltered. CONCLUSION: The relationship of the tumor to neighboring structures, i.e., the vertebral artery in particular, determines its resectability. We recommend using extreme caution with recurrent or en plaque meningiomas and tumors associated with extensive arachnoid scarring.

Adolescent↗
PubMed1995

Syringomyelia in association with tumours of the posterior fossa. Pathophysiological considerations, based on observations on three related cases.

In this report we describe 3 patients with syringomyelia in association with tumours of the posterior fossa. In each patient the syrinx was demonstrated on pre-operative magnetic resonance imaging (MRI). After total or partial removal of the tumour the syrinx collapsed. It is concluded that the pathogenesis of syrinx formation in this entity requires interference with normal cerebrospinal fluid (CSF) flow at the foramen magnum. We suggest that the obstruction to the flow of CSF causes alterations in the passage of extracellular fluid (ECF) in the spinal cord which lead to syringomyelia.

Adolescent↗
PubMed1994

Occult dysraphism in adulthood: clinical course and management.

We present a series of 23 patients with dysraphic malformations and adult onset of symptoms (4 meningoceles, 19 spinal hamartomas). Mean age at presentation was 39 +/- 21 years (range 23-67 years). Patients were followed up for a mean period of 19 months (range 0.5-68 months). Only patients with progressive neurological disease were operated on (3 meningoceles and 16 spinal hamartomas). The remaining patients were treated conservatively and continue to be observed clinically. Two of three patients operated for meningoceles improved without recurrence of symptoms. Patients with spinal hamartomas could be divided into two groups according to their main symptom: paraparesis (group A, n = 8) or pain (group B, n = 11). Malformations in group B were typically associated with a tethered cord and tended to be more complex than in group A. The majority of patients in group A showed better long-term results than patients in group B, due to their considerably lower rate of recurrence.

Adult↗
PubMed1994

Arteriographic incidence of coronary artery disease in black men with chest pain.

To determine the incidence of arteriographically proven coronary artery disease in black men evaluated for chest pain, we retrospectively reviewed the charts of 208 black men, aged 20 to 60, who had coronary arteriography at the Medical Center of Central Georgia (MCCG) from 1985 through January 1990. Age, type of chest pain, and risk factors commonly accepted as associated with coronary disease (hypertension, family history, left ventricular hypertrophy, diabetes, smoking, and hypercholesterolemia) were identified for each patient. Patients were categorized by previous evidence of coronary disease: 145 were studied to evaluate suspected disease and 63 to evaluate previously proven (prior catheterization) or presumptive (prior myocardial infarction) disease. Chest pain groups (typical and atypical angina) were analyzed by Pearson chi-square goodness of fit using the Diamond and Forrester age and chest pain tables as a model. Risk factors were analyzed using a maximum likelihood chi-square test. Coronary artery disease was common in the study group (48.6% of all patients) but significantly less than predicted by the Diamond and Forrester tables. Risk factors were highly prevalent, but only age and smoking were associated with catheterization-proven coronary artery disease in this group. We conclude that coronary artery disease is common in black men evaluated for chest pain but less frequent than would be expected from comparison with findings in white men presenting similar clinical features. Risk factors other than age and smoking were not associated with increased incidence of disease. A prospective study is needed to delineate a more effective means of evaluating black male patients with chest pain.

Adult↗
PubMed1994

Surgical results of 100 intramedullary tumors in relation to accompanying syringomyelia.

During the period from 1977 to August 1992, 100 intramedullary tumors in 94 patients were operated on in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany. Of these, 45% presented with associated syringes. A syrinx was more likely to be found above (49%) than below (11%) the tumor level. In 40%, a syrinx could be identified above and below the tumor level. Ependymomas and hemangioblastomas were the most common tumor types to be associated with syringes. Astrocytomas tended to demonstrate syringes less often. Regardless of histology, the higher the spinal level, the more likely a syrinx was encountered. In general, the presence of an associated syrinx favored the resectability of the tumor, because it indicated a displacing rather than an infiltrating tumor. Patients with syringomyelia tended to recover from surgery sooner. However, surgical results and long-term prognosis were not influenced significantly by an associated syrinx. The most important factor determining long-term outcome was the preoperative level of neurological function. We propose that factors independent of the tumor, disturbances of cerebrospinal fluid and extracellular fluid flow in particular, have major roles in the pathogenesis of syrinx formation associated with intramedullary tumors.

Adolescent↗
PubMed1993

Introduction of a score system for the clinical evaluation of patients with spinal processes.

To facilitate statistical analysis of the clinical course of patients with spinal lesions such as tumours, dysraphic malformations, inflammation, or syringomyelia, we have developed a score system for each of the following symptoms and signs: sensory deficits, dysaesthesiae, pain, motor weakness, gait, bladder and bowel function. For each a score between 0 and 5 is given. The grading is designed in such a way that levels of functional significance receive separate scores: 0 = no function, 1 = severely disabled, 2 = disabled, 3 = severely compromised but function preserved, 4 = slightly compromised, and 5 = normal function. In general, scores between 0 and 2 indicate insufficient functional capacity and an unsatisfactory condition. Scores between 3 and 5 represent levels of function which should be the aim of treatment. We have used this scoring system for evaluation of almost 500 patients with spinal lesions both retrospectively and prospectively with good results in terms of reproducibility and validity.

Disability Evaluation↗
PubMed1991

Morphometric study on the postnatal growth of the hippocampus in Australian Aborigines and Caucasians.

In an autopsy study on Australian Aborigines (29 males, 27 females) and Caucasians (57 males, 37 females) the postnatal growth of the hippocampus was studied and described by mathematical growth functions. For male adults no significant difference in hippocampal volume was found. In contrast, hippocampal volume was significantly smaller for Aboriginal females compared to Caucasian females. Growth analysis showed slower growth rates and later half-value times for Aborigines compared to Caucasians. These results are discussed in relation to secular changes of growth parameters of the human brain during the last century, the socioeconomic and health status of Aborigines, and sexual differences in development and plasticity of the hippocampus.

Adolescent↗
PubMed1991

Quantitative changes during the postnatal maturation of the human visual cortex.

Postnatal development of the human visual cortex is characterized by an overshooting growth pattern of its volume with a maximum at 8 postnatal months and by loss of a substantial proportion of its neurons. The highest rate of reduction in neuronal numbers is observed in layers II-IVa, with other layers showing a more gradual postnatal decrease.

Adolescent↗
PubMed1989

Morphometric study on the postnatal growth of the cerebellum of Australian aborigines and Caucasians.

In an autopsy study on 29 male Aborigines and 57 male Caucasians, macroscopic and microscopic parameters of postnatal cerebellar development were determined and described by mathematic growth functions. For the whole cerebellum and its cortical layers volume measurements revealed delayed maturation for Aborigines compared to Caucasians. Despite the slower development in childhood, significantly smaller values for adult Aborigines compared to Caucasians were observed only for the whole cerebellum and the Purkinje cell sheet. Similarly, postnatal changes in Purkinje cell size showed prolonged growth phases in Aborigines compared to Caucasians. Calculations of absolute cell numbers for individual layers demonstrated later half-value times and slower growth rates for cell numbers in the internal granular and molecular layers consistent with the findings for the corresponding layer volumes. For Caucasians, the growth curve for the absolute cell number in the internal granular layer showed a maximum about 21 months postnatally and subsequently decreased towards adulthood by about 18%. No such overshoot could be demonstrated for Aborigines. In relation to absolute cell numbers in adulthood, this could indicate a smaller number of granule cells migrating from the external to the internal granular layer as well as less pronounced granule cell death in Aborigines compared to Caucasians. The external granular layer of Caucasians increased in volume postnatally to reach a maximum at about 4 months and subsequently decreased until its disappearance at approximately 2 years of age. The number Purkinje cells decreased marginally postnatally in both populations. These results were discussed in relation to secular changes of growth parameters of the cerebellum during the last century and the socioeconomic and health status of Aborigines.

Adolescent↗
PubMed1989

Morphometric study on the postnatal growth of non-cortical brain regions in Australian aborigines and Caucasians.

In an autopsy study on 29 male and 27 female Aborigines and 57 male and 37 female Caucasians the volumes of a large number of brain regions were determined and fitted to logistic growth functions. For Aboriginal adults significantly smaller values were found for weight and volume of the whole brain, cerebrum, and cerebellum and for the volumes of cerebral white matter, thalamus, amygdaloid body (females only), and globus pallidus (males only). No significant differences were found for caudate nucleus, putamen, amygdaloid body (males only), and globus pallidus (females only). Almost every region studied showed later half-value times, slower growth rates, and prolonged growth phases for Aborigines compared to Caucasians. These results are discussed in relation to secular changes of growth parameters of the human brain during the last century, timing of growth phases for each area, and the socioeconomical and health status of Aborigines.

Adolescent↗
PubMed1987

The morphology of Australian aboriginal brains--documentation of eight cases.

Cortical morphology of the brains of eight Western Australian Aboriginals was documented. Sulcal patterns permitted classification of the brains into separate groups. Characteristic patterns were found for the shape of the prosencephalon and for the insular, parietooccipital, and frontal cortex in the aboriginal group. The length of the frontal, parietal, and occipital lobes and the width of the temporal lobes was measured. Length, width, and height of the Aboriginal prosencephalons were compared to measurements of eleven Caucasian brains. Postmortem changes, genetic differences, and factors influencing brain development were discussed.

Adult↗
PubMed1987

A quantitative study of Australian aboriginal and Caucasian brains.

The brain volumes of 8 male Australian Aborigines and 11 male Caucasians were determined. Total brain volume was significantly smaller for Aborigines (1199 +/- 84 ml) compared to Caucasians (1386 +/- 98 ml). Significantly smaller volumes were also found for cerebellum, prosencephalon-mesencephalon unit, cerebral cortex, frontal cortex, parieto-occipitotemporal cortex, and hippocampus. Volumes of ponsmedulla oblongata unit (21 +/- 3 ml for Aborigines and 22 +/- 3 ml for Caucasians) and visual cortex (14.9 ml +/- 2.6 ml and 14.6 +/- 2.2 ml, respectively) did not differ significantly. The striate cortex extended further onto the lateral surface of the occipital lobe in Aboriginal brains. The frontal portion of cerebral cortex was larger in Aboriginal than in Caucasian brains. According to the specific growth periods for the areas studied, these differences could be explained by the higher incidence of malnutrition and infectious diseases for Aboriginals during the development of the brain in early childhood, especially after the 6th postnatal month. However, genetic influences cannot be excluded. The results for the visual cortex of Aborigines might represent an adaptation to living conditions in the bush and desert regions of Australia.

Adult↗
PubMed1985

A new embedding and sectioning technique (macrovibratome) for macroscopic and morphometric examinations especially of the human brain.

The macrovibratome is a newly developed sectioning apparatus designed especially for the preparation of human brain material subject to macroscopic and morphometric examinations. The brain is embedded in an aqueous agar solution and cut into slices with a minimum thickness of 2 mm. Using a 20% or 40% gelatin solution as the embedding material results in an average shrinkage of the tissue blocks of 9.8 or 31.7% in volume, respectively. With a 3% agar solution the volume shrinkage lies on the average at 1.0% for smaller brain pieces and 4.5% for cerebra.

Agar↗