STUDIES in SPINA BIFIDA CYSTICA I GENERAL SURVEY and REASSESSMENT of the PROBLEM by PATRICIA ANNE DORAN and A
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J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.24.4.331 on 1 November 1961. Downloaded from J. Neurol. Neurosurg. Psychiat., 1961, 24, 331. STUDIES IN SPINA BIFIDA CYSTICA I GENERAL SURVEY AND REASSESSMENT OF THE PROBLEM BY PATRICIA ANNE DORAN and A. N. GUTHKELCH From the Royal Manchester Children's Hospital, Pendlebury, near Manchester Nicolai Tulp, the physician whose features are these tissue with the skin or the external body surface immortalized in Rembrandt's painting 'The School itself. The second part of this definition is added so of Anatomy', first suggested the name 'spina bifida' as to include those cases, sometimes termed (Tulpius, 1652), though the condition was known to myelocoele, in which, although the abnormal spinal Hippocrates, and the mediaeval Arab physicians cord is lying exposed in the mid-line of the back, are said (Denuce, 1906) to have specifically re- there is no actual cystic protrusion. Rarely, of cognized the absence of the spinous processes in the course, one may see examples of 'anterior spina affected area. Ruysch (1691) distinguished between bifida' in which the protrusion is through a cleft in the paralytic and non-paralytic forms of spina one or more of the vertebral bodies, usually in the guest. Protected by copyright. bifida cystica and came near to discovering its sacral region, but no such case occurred in the association with hydrocephalus when he remarked present series. that the two, allowing for the difference in site, were Classification of the various forms of spina bifida almost the same disorder. The clear recognition of cystica is far from easy. From the point of view of this association, however, had to wait for Morgagni morbid anatomy, it is perhaps most satisfactory to (1769), and detailed description of the many varieties divide the cases according to the constituents of the of spina bifida only began in the later nineteenth sac, and the simplest division is into simple menin- century (Marsh, Gould, Clutton, and Parker, 1885; gocoele, in which the swelling is composed simply of von Recklinghausen, 1886). a herniation of dura and arachnoid filled with The literature on the subject of spina bifida is cerebrospinal fluid (C.S.F.), and myelomeningocoele, already vast (for bibliography, see Ingraham, Swan, in which the sac also contains parts of the spinal Hamlin, Lowrey, Matson, and Scott, 1943), and it is cord and nerve roots. This is the classification which not without trepidation that we set out to increase it. will be adopted in this paper, though it has the We do so because not only is spina bifida cystica a limitations of having no direct relationship to common cause ofdisability in infancy and childhood, function in the neurological sense. Even when the but also, as improved medical care allows more cyst itself contains no neural elements, it may none crippled children to survive into adult life, it may the less be associated with the presence of abnormal well become in the future an even greater medical neurological signs and of weakness of the limbs and and social problem than it is now (Nash, 1956). It sphincters. This is due to an underlying maldevelop- http://jnnp.bmj.com/ was therefore decided to review a series of cases of ment of the spinal cord itself, and in the course of spina bifida cystica seen during the years 1948-58. removing these innocent swellings, we have on several All but 10 ofthese have been traced and the minimum occasions verified the existence of an underlying period of follow-up of the survivors is two and a hydromyelia or diastematomyelia. Similarly, al- half years. though the majority of cases of myelomeningocoele are associated with partial or complete paralysis, Definition and Classification yet elements of the cord and nerve roots may enter We define spina bifida cystica as a congenital into the composition of the swelling without any on September 23, 2021 by anomaly of development in which there is a defect of functional disability resulting. An interesting ex- fusion of the posterior neural arch of one or more ample of this is seen in the variety of spina bifida vertebrae accompanied by a protrusion of the cystica which involves the cervical or thoracic regions membranes of the spinal theca, with or without the of the cord, and which in the past has sometimes cord and nerve roots, beyond the expected limits of been termed a syringocoele. Here, there is a hydro- the spinal canal, or with an abnormal contiguity of myelia of the cord which usually extends for several 33 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.24.4.331 on 1 November 1961. Downloaded from 332 PATRICIA ANNE DORAN AND A. N. GUTHKELCH segments above and below the spina bifida deformity the primary disturbance may sometimes be related itself. At the level of the defective fusion of the to the time of closure of the blastopore. Extreme neutral arches there protrudes a swelling which can retardation of this event under the influence of be shown by careful dissection to be composed of x-radiation can lead, in amphibia, to monsters with two different sacs. The outer sac is lined by the dura two spinal cords and rumps, while lesser degrees and contains cerebrospinal fluid. Inside this there is of retardation result in diastmatomyelia and spina a thin, red, more delicate swelling, which proves to bifida. Barry, Patten, and Stewart (1957) have be protruding from the mid-line of the posterior shown that in the grosser degrees of spina bifida aspect of the cord, between the posterior columns cystica associated with the Arnold-Chiari mal- themselves. It is made up of ependyma with a small formation there is an overgrowth of the tissue of the number of ganglion cells in its walls. It is continuous central nervous system, relative to its coverings, with the dilated central canal of the cord but can which they have identified early in intrauterine life safely be amputated without causing any damage to in human foetuses. They consider that this over- the latter. This lesion is not seen at lower levels, growth so broadens the embryonic spinal cord that although the large and complicated myelomeningo- the neural tube cannot completely close during the coeles of the lumbar region often contains cystic period in which the organizer which determines this spaces which are undoubtedly hydromyelic dilata- closure is still operative. tions of the malformed cord. Browne (1955) suggested that the spinal mal- formation was a result of an insufficient quantity of Developmental Considerations liquor amnii, the foetus being therefore subjected to During the second week of foetal life the neural abnormal mechanical pressures from the uterine tube develops from surface ectoderm, the meninges wall. This would cause it to assume an attitude of from a mesodermal anlage, and the spinal column hyperflexion with consequent malunion of the spinalguest. Protected by copyright. by a condensation of scleroderm around the noto- laminae with or without herniation of the spinal chord. 'The neural ectoderm detaches itself from the contents but Browne's hypothesis cannot account superficial ectoderm and gives rise through a for all cases ofrachischisis since there is an 11 to 12 % thickening of its walls to the brain and spinal cord. incidence of hydramnios in all pregnancies in which The latter is formed by a process of uniform the infant is born with spina bifida and hydro- thickening in the walls of the caudal portion of the cephalus (Stevenson, 1960). It is a priori difficult to tube while the former results from the more rapid believe that insufficiency of the liquor in early preg- but uneven growth of the rostral portion. The trans- nancy is followed by an excess of it later on. formation of groove into tube begins near the middle Table I shows the anatomical distribution of the of the embryonic body, and from this point closure spina bifida deformity in all our cases and shows no proceeds in both directions. The last points to close material differences from the findings of other work- are situated at either end and are known as neuro- ers. The much greater frequency with which pores' (Ranson, 1959). This process is complete by the fourth week of intra-uterine life and the verte- TABLE I bral laminae are developed and fused by the eleventh SITUATION OF SPINA BIFIDA CYSTICA IN 307 CASES week. Simple Myelo- It is agreed that spina bifida is a result of a mal- Site Meningocoele meningocoele Total development at this early stage of foetal life, and Cervical 6* 6 12 that it is a manifestation of some disturbance in the Thoracic 7 13 20 Thoracolumbar 3 29 32 http://jnnp.bmj.com/ mechanism of closure of the neural tube, either of Thoraco-lumbo-sacral 0 10 10 Lumbar 23* 77 100 chromosomal origin or due to a noxious stimulus Lumbosacral 13 83 96 acting upon the organizer which determines its final Sacral 13 25 38 form. The administration of massive doses of Totals 65 243 308 vitamin A to pregnant rats causes the appearance of a large number of offspring with congenital *One case had both a cervical and a lumbar meningocoele. malformations, among these anencephaly and spina bifida (Cohlan, 1954), and craniorachischisis can spina bifida cystica affects the lower as against the on September 23, 2021 by also be produced in the same species by salicylate upper parts of the spinal column is clearly shown. poisoning (Warkany and Takacs, 1959). In the The ratio of simple meningocoeles to myelomenin- rat, the critical time for the administration of the gocoeles is about 1: 3 7 which represents a higher toxic substance, if spina bifida is to result, appears incidence of myelomeningocoeles than in the series to be the tenth day after mating (Kalter and reported by Ingraham and Matson (1954), but this Warkany, 1961).