Finite Element Analysis: A Maxillofacial Surgeon’s Perspective

The science of finite element analysis (FEA) is purely a mathematical way of solving complex problems in the universe. In medical field, this is an innovation in biomedical research and development, as it gives easier mathematical solution to biological problems. This article deals with the understanding of various basic material properties of bone like Young’s modulus, yield strength, Bulk modulus, shear modulus, Poisson’s ratio and density from a maxillofacial surgeon’s perspective. Basic concepts in FEA, its application, advantages, disadvantages, and limitations in the field of maxillofacial surgery have been discussed. The importance of surgical fraternity to be in coordination with evolving technologies has been emphasized for the future of evidence based practice of oral and maxillofacial surgery.     

Gastrointestinal mucormycosis—four cases with different risk factors, involving different anatomical sites

Mucormycosis of the gastrointestinal tract is a rare infection that usually occurs in patients who are immunocompromised and carries a high mortality. We report four cases of gastrointestinal mucormycosis seen over a one year period with different presentations, risk factors and different anatomical sites of involvement. A preoperative diagnosis was made only in one patient. All underwent surgery, three survived and one died postoperatively from multiorgan failure.     

Dysregulation of innate immunity in hepatitis C virus genotype 1 IL28B-unfavorable genotype patients: impaired viral kinetics and therapeutic response

Recent studies have shown that a single-nucleotide polymorphism upstream of the interleukin-28B (IL28B) gene plays a major role in predicting therapeutic response in hepatitis C virus (HCV)-infected patients treated with pegylated interferon (PEG-IFN)/ribavirin. We sought to investigate the mechanism of the IL28B polymorphism, specifically as it relates to early HCV viral kinetics, IFN pharmacokinetics, IFN pharmacodynamics, and gene expression profiles. Two prospective cohorts (human immunodeficiency virus [HIV]/HCV-coinfected and HCV-monoinfected) completing treatment with IFN/ribavirin were enrolled. Patients were genotyped at the polymorphic site rs12979860. In the HIV/HCV cohort, frequent serum sampling was completed for HCV RNA and IFN levels. DNA microarray of peripheral blood mononuclear cells and individual expression of IFN-stimulated genes (ISGs) were quantified on IFN therapy. The IL28B-favorable (CC) genotype was associated with improved therapeutic response compared with unfavorable (CT or TT) genotypes. Patients with a favorable genotype had greater first- and second-phase viral kinetics (P = 0.004 and P = 0.036, respectively), IFN maximum antiviral efficiency (P = 0.007) and infected cell death loss (P = 0.009) compared with unfavorable genotypes. Functional annotation analysis of DNA microarray data was consistent with depressed innate immune function, particularly of natural killer cells, from patients with unfavorable genotypes (P <0.004). Induction of innate immunity genes was also lower in unfavorable genotypes. ISG expression at baseline and induction with IFN was independent of IL28B genotype. CONCLUSION: Carriers of the IL28B-favorable genotype were more likely to have superior innate immune response to IFN therapy compared with unfavorable genotypes, suggesting that the unfavorable genotype has aberrant baseline induction of innate immune response pathways resulting in impaired virologic response. IL28B genotype is associated with more rapid viral kinetics and improved treatment response outcomes independent of ISG expression.     

Coagulopathy Disproportionately Predisposes to Lobar Intracerebral Hemorrhage

Background

Anticoagulation increases the risk of intracerebral hemorrhage (ICH), yet whether different underlying disease processes are equally affected is unknown. We tested the hypothesis that coagulopathy, measured by admission international normalized ratio (INR), disproportionately increases the risk for lobar hemorrhages.

Methods

Patients with primary ICH were enrolled into a registry between December 2006 and February 2012 with prospective data acquisition and systematic follow up. Logistic regression was used to test whether lobar versus deep ICH location was independently associated with INR, and then whether INR had an influence on mortality. Spearman’s correlation coefficient was used to test for an association between INR and hematoma volume separately in the lobar and deep ICH groups.

Results

221 patients were studied. Patients with lobar ICH were older (71 vs. 62 years old, p < 0.001) and more likely to have prior ICH (10 vs. 0 %, p < 0.001). INR >1.4 was observed on admission more frequently in lobar versus deep ICH (19 vs. 8 %, p = 0.02). Lobar ICH location was independently associated with INR >1.4 (OR: 2.51, 95 % CI: 1.03–6.14, p = 0.043). ICH volume correlated with INR in lobar ICH (p = 0.009), but not deep ICH (p = 0.8). Death at 1 month was independently associated with INR >1.4 (OR: 7.6, 95 % CI: 2.4–24.1, p = 0.001) after correction for the ICH Score.

Conclusions

Abnormal coagulation occurs disproportionally in lobar versus deep ICH, and is associated with larger ICH volumes and higher mortality. These findings suggest a unique risk interaction between coagulopathy and underlying brain pathology due to cerebral amyloid angiopathy.     

Basic research: Issues with animal experimentations

In vivo studies using the animals are helpful in developing the treatment strategies as they are important link between the successful in vitro testing and safe human use. Various research projects in the field of fixation of fractures, development of newer biomaterials, chemotherapeutic drugs, use of stem cells in nonunion of fractures and cartilage defects etc., have hugely depended on animal experimentation. The employment of animals in experiments is both scientific and ethical issue. There must be reasonable reasons to show that it will significantly advance the present knowledge and lead to improvement in care. The regulatory bodies exist for humane use and care of animals used for experiments e.g., International Council for Laboratory Animal Science, Council for International Organizations of Medical Sciences, International Union of Biological Sciences, International Committee on Laboratory Animals. In India, Indian National Science Academy, Indian Council of Medical Research, National Centre for Laboratory Animal Sciences promote high standards of laboratory animal quality, care and health. The Committee for the Purpose of Control and Supervision on Experiments on Animals guidelines are well defined and is a must read document for any one interested to carry out research with animal facilities.     

The CT guided transoral approach: A biopsy technique for a poorly differentiated chordoma in a 5 year old

Mass lesions presenting at the craniocervical junction often present a unique challenge due to the complex anatomic arrangement limiting access for tissue diagnosis. The transoral approach has predominantly been used for percutaneous vertebroplasty of high cervical vertebrae with limited literature describing image guided biopsy for bony lesions in this region in the pediatric patient. We describe a technique of computed tomography guided transoral biopsy of a poorly differentiated chordoma located at the C1–C2 level in a 5-year-old child, and review this diagnosis.     

Temporal Trends,Practice Patterns,and Treatment Outcomes for Infected Upper Urinary Tract Stones in the United States

Background

The incidence of infected urolithiasis is unknown, and evidence describing the optimal management strategy for obstruction is equivocal.

Objective

To examine the trends of infected urolithiasis in the United States, the practice patterns of competing treatment modalities, and to compare adverse outcomes.

Design, setting, and participants

A weighted estimate of 396 385 adult patients hospitalized with infected urolithiasis was extracted from the Nationwide Inpatient Sample, 1999–2009.

Outcome measurements and statistical analysis

Time trend analysis examined the incidence of infected urolithiasis and associated sepsis, as well as rates of retrograde ureteral catheterization and percutaneous nephrostomy (PCN) for urgent/emergent decompression. Propensity-score matching compared the rates of adverse outcomes between approaches.

Results and limitations

Between 1999 and 2009, the incidence of infected urolithiasis in women increased from 15.5 (95% confidence interval [CI], 15.3–15.6) to 27.6 (27.4–27.8)/100 000); men increased from 7.8 (7.7–7.9) to 12.1 (12.0–12.3)/100 000. Rates of associated sepsis increased from 6.9% to 8.5% (p = 0.013), and severe sepsis increased from 1.7% to 3.2% (p < 0.001); mortality rates remained stable at 0.25–0.20% (p = 0.150). Among those undergoing immediate decompression, 113 459 (28.6%), PCN utilization decreased from 16.1% to 11.2% (p = 0.001), with significant regional variability. In matched analysis, PCN showed higher rates of sepsis (odds ratio [OR]: 1.63; 95% CI, 1.52–1.74), severe sepsis (OR: 2.28; 95% CI, 2.06–2.52), prolonged length of stay (OR: 3.18; 95% CI, 3.01–3.34), elevated hospital charges (OR: 2.71; 95%CI, 2.57–2.85), and mortality (OR: 3.14; 95%CI, 13–4.63). However, observational data preclude the assessment of timing between outcome and intervention, and disease severity.

Conclusions

Between 1999 and 2009, women were twice as likely to have infected urolithiasis. Rates of associated sepsis and severe sepsis increased, but mortality rates remained stable. Analysis of competing treatment strategies for immediate decompression demonstrates decreasing utilization of PCN, which showed higher rates of adverse outcomes. These findings should be viewed as preliminary and hypothesis generating, demonstrating the pressing need for further study.