Anatomical variations of the common carotid artery bifurcation.

BACKGROUND: The correlation of the common carotid artery (CCA) bifurcation and its surrounding structures is poorly described. The aim of this study was to describe the anatomy of the CCA bifurcation relative to its surrounding structures. METHOD: We dissected a total of 67 carotid specimens from 36 embalmed cadavers. CCA bifurcation occurred at the superior border of thyroid cartilage in 39% and at the body of hyoid bone in 40% of specimens. RESULTS: The superior thyroid artery arose more commonly from the CCA (52.3%) than the external carotid artery (46.2%). The vagus nerve was posterior to the carotid bifurcation in 40 (60%), posterior-lateral in 24 (36%), posterior-medial in 2 (3%) and anterior-lateral in 1 specimen (1.5%). The hypoglossal nerve was closer to the CCA bifurcation when the CCA bifurcated at the level of the hyoid bone than when it bifurcated at the superior border of the thyroid cartilage (P < 0.05). The correlation of the common facial vein and the carotid artery was highly variable. CONCLUSION: The presence of a high CCA bifurcation should caution surgeons that the hypoglossal nerve lies in closer proximity and is more vulnerable. Preoperatively documenting the level of the CCA bifurcation may be helpful in identifying those patients at increased risk of iatrogenic injury.

Effectiveness of beta lactam antibiotics compared with antibiotics active against atypical pathogens in non-severe community acquired pneumonia: meta-analysis.

OBJECTIVE: To systematically compare beta lactam antibiotics with antibiotics active against atypical pathogens in the management of community acquired pneumonia. DATA SOURCES: Medline, Embase, Cochrane register of controlled trials, international conference proceedings, drug registration authorities, and pharmaceutical companies. Review methods Double blind randomised controlled monotherapy trials comparing beta lactam antibiotics with antibiotics active against atypical pathogens in adults with community acquired pneumonia. Primary outcome was failure to achieve clinical cure or improvement. RESULTS: 18 trials totalling 6749 participants were identified, with most patients having mild to moderate community acquired pneumonia. The summary relative risk for treatment failure in all cause community acquired pneumonia showed no advantage of antibiotics active against atypical pathogens over beta lactam antibiotics (0.97, 95% confidence interval 0.87 to 1.07). Subgroup analysis was undertaken in those with a specific diagnosis involving atypical pathogens. We found a significantly lower failure rate in patients with Legionella species who were treated with antibiotics active against atypical pathogens (0.40, 0.19 to 0.85). Equivalence was seen for Mycoplasma pneumoniae (0.60, 0.31 to 1.17) and Chlamydia pneumoniae (2.32, 0.67 to 8.03). CONCLUSIONS: Evidence is lacking that clinical outcomes are improved by using antibiotics active against atypical pathogens in all cause non-severe community acquired pneumonia. Although such antibiotics were superior in the management of patients later shown to have legionella related pneumonia, this pathogen was rarely responsible for pneumonia within the included trials. beta lactam agents should remain the antibiotics of initial choice in adults with non-severe community acquired pneumonia.