Classification of injuries to the thoracolumbar spine

Significant advances have been made over the past 40 years in the understanding of the pathoanatomy, biomechanics, and neurophysiology of thoracolumbar injuries. These improvements are reflected in the sophisticated classifications currently in use. Yet, we remain in a transitional phase of our classification of these fractures. Future schemes will probably offer two precise classifications--one neurologic and one structural--for every injury.     

Differential etiology of posttraumatic stress disorder with conduct disorder and major depression in male veterans.

BACKGROUND: Epidemiologic studies reveal that posttraumatic stress disorder (PTSD) is highly comorbid with both conduct disorder and major depression in men. The genetic and environmental etiology of this comorbidity has not been examined. METHODS: Data were analyzed from 6744 middle-aged male-male monozygotic and dizygotic twins from the Vietnam Era Twin Registry. Conduct disorder, major depression, and PTSD were assessed via telephone interview using the Diagnostic Interview Schedule for the DSM-III-R in 1992. Structural equation modeling was used to estimate additive genetic, shared environmental, and individual-specific environmental effects common and specific to conduct disorder, major depression, and PTSD. RESULTS: The association between conduct disorder and PTSD was explained primarily by common shared environmental influences; these explained 10% (95% confidence interval: 6%-17%) of the variance in PTSD. The association between major depression and PTSD was largely explained by common genetic influences; these explained 19% (95% confidence interval: 11%-26%) of the variance in PTSD. CONCLUSIONS: Our findings suggest that different etiologic mechanisms explain the association of conduct disorder and major depression with PTSD in male veterans. If replicated in other populations, results suggest research aimed at identifying specific genetic and environmental factors that influence PTSD may benefit from starting with those that have been more consistently and strongly associated with major depression and conduct disorder.     

Halo vest versus spinal fusion for cervical injury: evidence from an outcome study

The indications for surgical fusion, as opposed to halo fixation, in the management of cervical spine injury are still unclear. At St. Louis University Medical Center a conservative protocol has been adopted to treat almost all cervical spine fractures with halo fixation. To determine what factors have contributed to failure of halo fixation, the records and radiographs of all patients with cervical spine injuries who were treated at that institution between 1984 and 1986 were reviewed. During this interval, 124 patients were treated, consisting of 93 men and 31 women between 6 and 94 years old. Of these, 15 (12%) had cervical fusion without preoperative halo device application. This group included eight patients with old injuries and delayed diagnosis, three with nonreducible locked facets, and four with miscellaneous indications. The remaining 109 patients were treated with halo vests. Four died before completing the 3-month standard treatment. Of those completing the treatment, 48 had C1-2 level injuries and 57 had C3-T1 level injuries. Sixteen patients (15%) failed their halo treatments and required surgical fusion: eight while still in halo fixation and eight after they had completed treatment with a halo device. Failure of halo treatment was indicated by recurrent dislocation in 13 patients and increased neurological deficit in three. Thirteen of the patients who failed treatment had C3-T1 injuries and three had C1-2 injuries. Of 27 patients with odontoid fractures, only two (7.4%) failed halo fixation. There were no failures in 11 patients with hangman's fractures. Of the 57 patients with C3-T1 injuries, 13 (23%) failed treatment, nine of whom had locked or "perched" facets. The factors causing failure of halo fixation were analyzed. The overall success rate was 85%, suggesting that the halo vest can be used to treat most patients with cervical spine injuries. Under certain circumstances (in the presence of old injuries, difficult reduction, or locked or "perched" facets), surgery may be indicated to avoid unnecessary delay in definitive management.     

Contributions of parental alcoholism, prenatal substance exposure, and genetic transmission to child ADHD risk: a female twin study

BACKGROUND: Genetic influences have been shown to play a major role in determining the risk of attention-deficit hyperactivity disorder (ADHD). In addition, prenatal exposure to nicotine and/or alcohol has also been suggested to increase risk of the disorder. Little attention, however, has been directed to investigating the roles of genetic transmission and prenatal exposure simultaneously. METHOD: Diagnostic telephone interview data from parents of Missouri adolescent female twin pairs born during 1975-1985 were analyzed. Logistic regression models were fitted to interview data from a total of 1936 twin pairs (1091 MZ and 845 DZ pairs) to determine the relative contributions of parental smoking and drinking behavior (both during and outside of pregnancy) as risk factors for DSM-IV ADHD. Structural equation models were fitted to determine the extent of residual genetic and environmental influences on ADHD risk while controlling for effects of prenatal and parental predictors on risk. RESULTS: ADHD was more likely to be diagnosed in girls whose mothers or fathers were alcohol dependent, whose mothers reported heavy alcohol use during pregnancy, and in those with low birth weight. Controlling for other risk factors, risk was not significantly increased in those whose mothers smoked during pregnancy. After allowing for effects of prenatal and childhood predictors, 86% of the residual variance in ADHD risk was attributable to genetic effects and 14% to non-shared environmental influences. CONCLUSIONS: Prenatal and parental risk factors may not be important mediators of influences on risk with much of the association between these variables and ADHD appearing to be indirect.     

Cancer of the colon in an egg donor: policy repercussions for donor recruitment

This paper describes the tragic case of a young woman who died of cancer of the colon after successfully donating eggs to her younger sister. Although there is no direct link between her operation and the subsequent development of bowel carcinoma, this case imparts a feeling of unease when seen in conjunction with other cases reported during the last few years. It is a reminder that little is known of the long-term consequences of some aspects of assisted conception. Women undergoing ovarian stimulation for themselves or a matched recipient have the right to be advised, in an agreed format, that there is some concern about unproven potential risks from the stimulatory drugs. The safety of egg donors must assume priority over all other considerations, including lack of donors or any moral position. The recent decision by the Human Fertilisation and Embryology Authority (HFEA) to withdraw any form of payment or recompense to egg donors does not seem to us to be based on a balance of scientific advances, patient needs and the ethics of gamete supply. They state that the intention to withdraw payments was implicit in the 1990 Human Fertilisation and Embryology (HFE) Act. However the Act was based on the Warnock report made 6 years earlier. Even in 1990 ovum donation was uncommon and fertility drugs had not yet caused any unease. The Act provided the HFEA with discretionary powers to issue directions so that the future policies would be consistent with any emerging new medical evidence. It is imperative that the HFEA provide convincing evidence on how the current policy of payment to donors harms society, donors or recipients, and how in the UK the new policy will improve medical practice in assisted conception. Successful pilot studies must precede the implementation of any new policy. Failure to do this could cause irreversible harm to the practice of assisted conception using donor gametes, which will ultimately be against the basic aims of the 1990 HFE Act.      

Mutations in the Ca(2+)-sensing receptor gene cause autosomal dominant and sporadic hypoparathyroidism

Parathyroid hormone secretion is negatively regulated by a 7- transmembrane domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that activating mutations in this receptor might cause autosomal dominant hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified, in two families with ADHP, heterozygous missense mutations in the Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of 50 normal controls had either mutation. We also identified a de novo, missense Ca(2+)-sensing receptor mutation in a child with severe sporadic hypoparathyroidism. The amino acid substitution in one ADHP family affected the N-terminal, extracellular domain of the receptor. The other mutations involved the transmembrane region. Unlike patients with acquired hypoparathyroidism, patients with these mutations had hypercalciuria even at low serum calcium concentrations. Their greater hypercalciuria presumably reflected activation of Ca(2+)-sensing receptors in kidney cells, where the receptor negatively regulates calcium reabsorption. This augmented hypercalciuria increases the risk of renal complications and thus has implications for the choice of therapy.