Search

The fact that some brain tracts decussate accompanies medical students and neurologists and neurosurgeons during the whole period of their study, as well as in their work “careers”. We take the decussation of the pyramidal tract, anterolateral, lemniscal systems and visual pathways for granted and we describe contralateral hemipareses, hemiplegia, including alternating ones, Brown-Séquard’s spinal cord hemisyndrome and homonymous hemianopsia. We understand the central lesion of the facial nerve, presenting only with contralateral paresis of mouth muscles while the ability to close the eye is preserved. The other tracts which cross and in which we do not often realize this are for example the tracts of the dentate-rubro-olivary (Guillain-Mollaret’s) triangle, lemniscus lateralis (corpus trapezoideum) conducting hearing, tractus pontocerebellaris, and tractus dentatothalamicus (decussatio pedunculi cerebellaris superioris). The trochlear nerve, tectospinal tract (decussatio tegmenti dorsalis) and rubrospinal tract (decussation tegmenti ventralis) decussate in the mesencephalon, reticulospinal tracts are both crossed and also uncrossed and on the contrary the crossing of the interstitiospinal tract from the ncl. of Cajal and vestibulospinal tract from the ncl. of. Dieters are not present. We questioned this finding, so we conducted the review of the pertinent literature concerning the theories why the tracts cross, we added the mnemotechnic predator theory of the silur sea, and we concentrated on the phylogenetic differences in the architecture of vertebrate brains, with the help of dissection of brain cadavers from rabbit (Oryctolagus cuniculus), duck (Anas platyrhynchos domesticus) and carp (Cyprinus carpio). Based on our results, we are not able to answer all of the above-mentioned and further related questions, hence we present them to the reader in the form of a minimonography. [ABSTRACT FROM AUTHOR]

Chiasmal gliomas are rare brain tumors occurring especially in children. Their proper treatment is still controversial and consists of surgery, radiotherapy and chemotherapy. Surgical removal of these tumors can usually be only partial or subtotal and radiotherapy frequently follows. There are supporters of surgical approach, as well as its enemies. The author has been engaged in problems of optimal treatment of this entity for more than 10 years. He is offering a review of knowledge from the literature concerning surgical treatment of this disease in children. The great majority of articles in the literature are dealing with retrospective analysis of relatively small series of patients usually treated in single neurosurgical department and the surgical treatment is enclosed like a part of combined therapy. Articles dealing only with surgical treatment of chiasmal gliomas are few and reviews determining the contemporary role of surgery of this entity are also lacking. This was the main impulse for writing this compilation. The short history of surgical therapy is reviewed. Some new trends of this therapy are also mentioned (microsurgery, Cavitron Ultrasonic Surgical Aspirator and peroperative use of visual evoked potentials). Up to date criteria for surgical treatment of chiasmal gliomas in children are given-exploration of chiasmal region and performing a biopsy in all cases, radical surgery only in extrinsic gliomas of the chiasmal region and conservative surgical approach to intrinsic chiasmal gliomas. It is emphasized that the significance of obstructive hydrocephalus in this entity has not been fully estimated till now, as well as the role of shunting procedures. Surgical treatment remains, nevertheless, an important armamentarium in the management of chiasmal gliomas in children. (Ref. 20.)

Chiasmal gliomas are rare tumors occurring predominantly in children. Their treatment consists of surgery, radiotherapy and chemotherapy. Surgical removal can usually be only partial, and radiotherapy frequently follows. There are supporters of radiotherapy, as well as opponents. The author has been engaged in problems of optimal treatment of this entity for more than 10 years. He offers a review of knowledge provided by literature concerning radiotherapy of this disease in children. In the past he was enthusiastic for radiotherapy. Nevertheless after passing the Postgraduate course in paediatric neurosurgery in Bonn (1989), where J.F. Hirsch demonstrated very pessimistic progressive long-term harmful sequellae of irradiation of the developing child's brain, the author has re-evaluated his attitude to this therapy. The short history and basic physical principles of radiotherapy are reviewed. Some new trends of this therapy are also mentioned (hyperbaric oxygenation, radiosensitizing agents, hyperthermia etc.). Great attention is paid to the deleterious adverse effects of radiotherapy and to the possible technical parameters enabling to avoid them (optional daily fractions, optimal total dose, limiting age in infants etc.). Harmful effects of radiotherapy are reviewed in detail. The most frequent are chronic sequellae: brain atrophy, radiation-induced brain necrosis, progressive intellectual deterioration, growth retardation, panhypopituitarism, galactorea, learning disabilities, moya-moya syndrome, radiation-induced secondary brain tumors (especially gliomas). Risks of radiotherapy combined with chemotherapy are also emphasized. Nevertheless radiotherapy has remained an important therapeutical measure in the treatment of chiasmal gliomas in children with progressive disease in cases when surgery and chemotherapy have failed.

The authors analyse 200 visual fields (examine with automatic perimetry) of patients with the chiasmal syndrome. On the basis of their own results they recommend the use of quantitative perimetry for early diagnosis of visual field changes in the range of central visual field (0-30 degrees).

Chiasmal gliomas are rare tumors occurring predominantly in childhood. Their optimal treatment is still controversial. In the past only neurosurgeons (performing partial or subtotal removal of the tumor, biopsy or shunting procedure in hydrocephalus) and radiotherapeutists participated in their treatment. In the middle of the eighties there was only a single article dealing with chemotherapy of these tumors (Rosenstock, 1985). Since that time there was an increased number of articles about harmful effects of radiotherapy on the developing child's brain. Neurosurgeons are aware that they will not solve this problem alone. During the past 7 years we have observed gradual retreat from radiotherapy and an inclination to combined chemotherapy of the chiasmal gliomas in children. The author has been engaged in the research of this clinical entity for more than 10 years and he offers to readers a summary of the contemporary knowledge about chemotherapy of chiasmal gliomas in children. Despite the fact that there is lacking experience with long-term survivors after chemotherapy, which is extremely important especially in this disease, the preliminary short-term results of combined chemotherapy of chiasmal gliomas in children are promising. Rapid development of chemistry and pharmacology in the last few years is promising for the discovery of further, more effective anti-tumor drugs. Their new combinations could improve present non-satisfactory results of treatment of chiasmal gliomas in children. (Ref. 25.)