Levels of MMP-9 in patients with intracranial aneurysm: Relation with risk factors, size and clinical presentation.

BACKGROUND: Intracranial aneurysms are arterial anomalies affecting 2% to 3% of the general population in the world and these ruptures are associated with a high mortality. Some risk factors, such as age, gender, smoking, alcohol, hypertension and familial history are associated with the number of aneurysms and their size. In addition, inflammatory processes within the blood vessels of the brain can activate matrix metalloproteinase-9 (MMP-9), which degrades various components of the extracellular matrix, such as elastin. Thereby, this work has aimed at evaluating the relationship between plasma MMP-9 levels and the risk factors that are associated with intracranial aneurysm, as well as investigating the aneurysm statuses (ruptured and unruptured) and comparing them with the control volunteers. METHODS: Between August 2014 to June 2016, blood samples were collected from 282 patients (204 ruptured and 78 unruptured saccular intracranial aneurysms) and 286 control volunteers. The MMP-9 plasma levels were measured by ELISA. Statistical analyzes were performed with SPSS software when using parametric or nonparametric tests, after the normality tests. RESULTS: Higher levels of MMP-9 were found in the aneurysm groups as a whole and when they were stratified by rupture status, then compared with the control group (p < 0.0001). When stratifying them by diameter, those smaller than 7 mm presented high levels of MMP-9 (p < 0.0001), especially in the ruptured ones. As for risk factors, hypertension and smoking were the most important. However, hypertension was mostly associated with the ruptured aneurysms (p < 0.0001). CONCLUSIONS: High levels of MMP-9 were found in smaller ruptured and unruptured intracranial aneurysms (<7 mm) with strongest statistical associations than other sizes, especially when associated with smoking and hypertension.

First olfactory fiber as an anatomical landmark for frontal sinus surgery.

OBJECTIVES/HYPOTHESIS: Access to the frontal sinuses is technically challenging owing to their anterosuperior location, diverse anatomy, close proximity to critical structures and the need to work in a relatively narrow space with angled-lens endoscopes and instruments. This study attempts to study the relationship of the first olfactory fiber with the frontal sinus posterior wall, assessing its fidelity as a surgical landmark during frontal sinus surgery. STUDY DESIGN: Anatomic study. METHODS: Fifteen cadaveric specimens were studied. Measurements were obtained bilaterally using the data from individual CT scans. Median A-P was defined as the anteroposterior (A-P) diameter measured just lateral to the intersinus septum, paramedian A-P was measured 5 mm lateral to the septum, and maximum A-P was defined as the maximum anteroposterior diameter on axial images. A surgical navigation device was used to calculate the distance between the first olfactory fiber and the posterior table of the frontal sinus. RESULTS: The mean distance between the first olfactory fiber and the posterior wall of the frontal sinus was (4.03 ± 2.7) mm on the right side and (4.2 ± 2.9) mm on the left. This distance strongly correlated with the maximum A-P diameter of the sinus. CONCLUSIONS: In a cadaveric model, the first olfactory fiber was found to be an average of 4.0 mm posterior to the frontal sinus. The significant variability of this distance should be considered when using the first olfactory fiber to establish the posterior boundary of a frontal sinusotomy. Drilling no further posterior than 7 mm rostral to the first olfactory fiber would be safe in 91% of patients. LEVEL OF EVIDENCE: NA Laryngoscope, 126:1039-1045, 2016.