Percent spinal canal compromise on MRI utilized for predicting the need for surgical treatment in single-level lumbar intervertebral disc herniation

BACKGROUND CONTEXT: There is limited information describing the correlation between the initial quantitative measurements on magnetic resonance imaging (MRI) scans of disc herniation area, canal cross-section areas, percent canal compromise, and disc herniation location to the need for surgery. PURPOSE: Our aim is to determine if the size of disc herniation area, canal cross-section area, percent canal compromise, and disc herniation location taken from MRI images of patients with symptomatic single-level lumbar herniated intervertebral discs upon initial presentation to a spine surgeon, were predictive of the need for surgical treatment. STUDY DESIGN/SETTING: This is a retrospective case matched study of patient MRI images in the senior author's private practice. PATIENT SAMPLE: From a pool of 332 patients with sciatica caused by lumbar intervertebral disc herniations at our institution, 65 patients had surgery, of which MRI images were available and analyzed on 44 patients. Forty-four additional patients were randomly selected from the remaining 267 original group as nonoperative controls. METHODS: The axial MRI image showing the largest canal compromise by the herniated disc was selected for measurements. Using T1- and T2-weighted images, the areas of interest were digitally scanned at high resolution. The canal area and disc herniation area measurement were calculated from the total number of pixels per cross-sectional area, multiplied by a scan correction factor, mm(2) /pixel. Disc herniation locations were classified into either central or paracentral. The percent canal compromise was obtained by disc herniation area divided by canal cross-section area and multiplied by 100. RESULTS: The surgical group's overall mean herniated disc area was 219.6 square millimeter (mm(2)), 179.8 at L4-5, and 267.4 at L5-S1. The nonoperative group's overall mean herniated disc area was 178.4 mm(2), 135.1 at L2-3, 160.3 at L4-5, and 207.4 at L5-S1. The surgical group's overall mean canal cross-sectional area was 471.8 mm(2), 418.6 at L4-5, and 535.6 at L5-S1. The nonoperative group's overall mean canal cross-sectional area was 541.3 mm(2), 518.1 at L2-3, 446.8 at L4-5, and 669.9 at L5-S1. The overall percent canal compromise ratio in the surgery group was 46.7%, 44.1% at L4-5, and 49.8% at L5-S1. The overall percent canal compromise in the nonoperative group was 34.2%, 34.1% at L2-3, 36.1% at L4-5, and 31.8% at L5-S1. The percent canal compromise in central herniations at L4-5 level was 53.0% in the surgical group, and 32.8% in the nonoperative group; at the L5-S1 level surgical group percent canal compromise was 64.1% and in the nonoperative group canal compromise was 27%. L4-L5 level paracentral herniations canal compromise was 36.7% in the surgical group compared with 42.5% canal compromise in the nonoperative group. At the L5-S1 level the canal compromise was 45% in the surgical group and 34.8% in the nonoperative group. CONCLUSIONS: Our findings show a trend for patients treated with surgery to have larger disc herniation areas and smaller canal cross-section areas, corresponding to larger percent canal compromise than the nonoperative group. Centrally located herniations followed this trend closely at all levels studied. However, the paracentral herniation at the L4-5 level does not follow this trend, possibly because paracentral disc herniation clinical course is determined more by herniation location rather than the overall herniation size.     

Responses to questions by medical students about family practice

Medical students frequently have questions about the specialty of family practice. Responses to 30 questions commonly asked about family practice are presented with a review of recent literature. These responses may assist medical students and their advisors in considering the choice of family practice as a career.     

Herpetic croup: two case reports and a review of the literature

Croup is an acute infectious illness usually occurring in children; it is characterized by brassy cough and stridor. The main pathogens include mainly parainfluenza and influenza viruses. Recently there have been reports of prolonged croup caused by the herpes simplex viruses. We report two cases of prolonged croup due to herpes simplex types 1 and 2. We also review and summarize the reported pediatric cases of herpetic croup.     

Allele-specific differential expression of a common adiponectin gene polymorphism related to obesity

Adiponectin gene polymorphisms have recently been reported to be associated with obesity, insulin sensitivity, and the risk of type 2 diabetes. We examined a T94G polymorphism of the adiponectin gene in 245 ostensibly normal nondiabetic subjects. The G allele frequency was lower among subjects with higher BMI (> or =27) than in those with lower BMI. BMI was inversely correlated with the dose of G allele. Multivariate linear regression analyses showed that the adiponectin genotypes were significantly related to BMI after adjusting for age and gender. The dose of the G allele was associated with a reduction of approximately 1.12 kg/m(2) in BMI. We further found that the relative mRNA levels of G allele were consistently higher than those of T allele in the omental adipose tissue from 21 heterozygous subjects. Finally, we observed that the expression levels of adiponectin affected insulin-stimulated glucose uptake in differentiated 3T3-L1 adipocytes. In conclusion, the allele-specific differential expression of this common polymorphism could be responsible for its biological effects observed in this and the other studies.     

IMMUNOHISTOCHEMICAL DISTRIBUTION OF CANNABINOID CB 1 RECEPTOR IN THE RAT CENTRAL NERVOUS SYSTEM

IMMUNOHISTOCHEMICAL DISTRIBUTION OF CANNABINOID CB 1 RECEPTOR IN THE RAT CENTRAL NERVOUS SYSTEM@邹冈     

Suppression of noxious stimulus-evoked expression of Fos protein-like immunoreactivity in rat spinal cord by a selective cannabinoid agonist

In rats, cannabinoids inhibit behavioral responses to noxious stimulation with a potency and efficacy similar to that of morphine. However, because cannabinoids depress motor function, it has not been possible to state beyond any doubt that these effects were related to a dampening of noxious sensory input. Therefore, c-fos immunocytochemistry was used to explore the possibility that cannabinoids reduce behavioral responses to noxious stimuli by decreasing spinal processing of nociceptive inputs. Rats received systemic injections of the potent and selective cannabinoid agonist WIN 55,212-2, the receptor-inactive enantiomer WIN 55,212-3 or vehicle prior to observations in a model of tonic pain, the formalin test. As demonstrated previously, plantar injections of formalin led to lifting and licking of the injected paw, with two peaks of activity occurring at 5 and 30 min after injection. The cannabinoid agonist suppressed these pain responses and produced a reduction in mobility. Immunocytochemical processing of sections with an antibody to the Fos protein revealed that the cannabinoid markedly suppressed pain-evoked c-fos expression in the superficial and neck regions of the spinal dorsal horn, but not in the nucleus proprius. Decreased expression of c-fos also occurred in the ventral horn. The specificity of this effect and its probable mediation by cannabinoid receptors are suggested by three findings: (i) the suppression by the drug of both behavioral and immunocytochemical responses to pain was dose-dependent; (ii) neither the behavioral nor the immunocytochemical response to the noxious stimulus was significantly affected by the receptor-inactive enantiomer of the agonist; (iii) animals rendered tolerant to cannabinoids by repeated injections of the agonist showed reduced responses to the drug. These findings suggest that cannabinoids inhibit the spinal processing of nociceptive stimuli and support the notion that endogenous cannabinoids may act naturally to modify pain trnasmission within the central nervous system.     

Primitive Neuroectodermal Tumors of the Central Nervous System

Controversial issues relating to the pathobiology and classification of central nervous system primitive neuroectodermal tumors (PNETs) have plagued neuropathologists for more than 70 years. Hypotheses advanced in the mid-1920's have remained as fixed concepts in contemporary literature, largely consequent to repetitious support by a small number of neuropathologists despite a growing body of information discrediting these ideas from neuroembryologists, oncologists, neuroscien-tists and pathologists.
Attention has largely focused upon PNETs arising in the cerebellum (commonly known as medul-loblastomas [MBs]), because about 80% of central nervous system (CNS) PNETs originate in this site. It has been asserted that the 20% which do not are biologically different, although most individuals agree that the histological features of PNETs that occur in different sites throughout the CNS are indistinguishable from those growing in the cerebellum.
The historical aspects of this controversy are examined in the face of evidence that there is, in fact, a unique class of CNS tumors which should appropriately be regarded as primitive neuroectodermal in nature. Specifically, a number of different approaches to the problem have yielded data supporting this hypothesis. These approaches include the identification of patterns of expression among a variety of cellular antigens (demonstrated by the use of immunopathological techniques), molecular analyses of cell lines derived from these tumors, experimental production of PNETs and molecular genetic analyses.
Differences of opinion among surgeons, oncologists and radiotherapists are typically resolved by conducting cooperative studies of patients with these tumors who are diagnosed and treated at multiple centers.