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Biomedical subjects

Mark S Dias

Publications and source records attributed to Mark S Dias.

5 recordsLinked to original sources

The Chiari II malformation: cause and impact.

INTRODUCTION: It is the Chiari II malformation and its effects that determine the quality of life of the individual born with spina bifida. DISCUSSION: The cause of this malformation has been a source of debate for many years. Understanding the cause enables strategies for the management of problems created by this malformation to be developed. An open neural tube defect allows fluid to escape from the cranial vesicles, altering the intracranial environment and leads to all of the brain changes seen in the Chiari II malformation. Decompression of the intracranial vesicles causes overcrowding, decrease in the size of the third ventricle, and changes in the fetal skull. It also permanently links the intracranial ventricular system to the spinal cord central canal.

Animals↗

Bilateral retro-auricular dermal sinus tracts with intradural extension. Case report.

The authors describe a previously unreported malformation involving paired, bilaterally symmetrical dermal sinus tracts in the retro-auricular area, both of which passed through the asterion and posterior fossa dura mater to end intracranially. Cranial dermal sinus tracts are congenital lesions that virtually always originate from the midline scalp posteriorly at the external occipital protuberance, anteriorly at the nasion or along the nasal dorsum, or in the posterior parietal midline. A lateral origin is extremely rare, and intracranial extension of a lateral dermal sinus tract has not been reported previously. The authors propose an embryological mechanism to explain the origin of this rare malformation and discuss its management.

Dura Mater↗

Inflicted head injury: future directions and prevention.

Although described only a quarter century ago, progress in this area is rapid and increasing at an accelerated rate. As a group, neurosurgeons, and particularly pediatric neurosurgeons, potentially have a lot to offer, both in the hospital, the courtroom, and the laboratory. As practitioners who see large numbers of brain injuries, both accidental and inflicted, they can provide a unique perspective to child abuse colleagues; unfortunately, neurosurgeons shy away from doing so for a variety of reasons: (1) they are too busy with clinical practice and cannot afford to devote the (largely uncompensated) time involved in keeping up with the literature on the subject, reviewing the case files in detail, and testifying in court; (2) they are reluctant to take the stand and potentially be subjected to the ridicule (and even abuse) hurled by attorneys in the defense of their clients; (3) they are uncertain in their minds about the validity of the evidence in some cases, especially when the evidence is not iron-clad; and (4) they perhaps fear later retribution from people they have helped convict for these crimes. Whatever the reasons, neurosurgeons need to be more involved in these cases and to be both knowledgeable and reasonable in assessments of the cause of injury. In no other area of neurosurgery is the truth so critical, because the lives of the infants for whom they care, and those who might be accused unjustly of perpetrating a crime that they did not commit, hang in the balance. Neurosurgeons must be unerringly accurate in obtaining and recording clinical information and physical findings. When asked, they must not shy away from providing an answer, but only if well enough versed in the literature to be capable of so doing, because to provide false or inaccurate information is a disservice; to do so may condemn an innocent person to prison, or an innocent infant to death. If there is uncertainty, it is probably in the best interests of the child to have the case analyzed and represented by an expert who knows the literature well; there are many excellent and objective child abuse experts who can do this. Finally, the author believes that this should be a much more active area of research for neurosurgeons. Although there has been much progress, there are also a number of uncertainties that remain to be answered, only a few of which have been touched on here. There is much to be done in this important field; neurosurgeons must concentrate on finding adequate answers for those questions that remain.

Child↗

Magnetic resonance imaging correlation in pediatric spinal cord injury without radiographic abnormality.

OBJECT: The authors conducted a study to determine correlations between clinical syndromes and early magnetic resonance (MR) imaging-documented findings in children with spinal cord injury without radiographic abnormality (SCIWORA). METHODS: The authors retrospectively reviewed the records obtained in 20 patients who presented with SCIWORA to the Children's Hospital of Buffalo between 1992 and 1999. Initial neurological syndromes, subsequent hospital course and outcome, and early MR imaging findings obtained using conventional sequences on a 1.5-tesla unit were recorded. Neurological syndromes on presentation were complete (Frankel Grade A) in two patients (10%), severe partial (Frankel Grade C) in one patient (5%), and mild partial (Frankel Grade D) in 17 patients (85%). Partial neurological deficits resolved in 14 (78%) of 18 patients within 72 hours and lasted more than 72 hours in four patients (22%). Magnetic resonance imaging was performed in both patients presenting with complete injuries and in 17 of 18 patients presenting with partial neurological deficits. The studies were obtained within 24 hours in 17 patients (85%). Neuroimaging revealed spinal cord swelling at the cervical level in one of the children with complete injury and cord edema with associated hemorrhage at cervical and thoracic levels in the other. Neural and extraneural elements were shown to be normal in all 17 patients with partial injuries who underwent MR imaging, including in the four patients with partial motor deficits lasting more than 72 hours. CONCLUSIONS: In this series, the predominant neurological presentation of SCIWORA was a mild, partial syndrome that resolved within 72 hours. Magnetic resonance imaging revealed abnormal features only in those patients with complete neurological deficits. These findings suggest that in the acute setting conventional MR imaging sequences may lack the sensitivity to demonstrate neural and extraneural abnormalities associated with partial or temporary neurological deficits of SCIWORA, even when those deficits persist beyond 72 hours.

Adolescent↗