ObjectThe authors performed exploratory meta-analyses of observational cohort studies, evidence level III, examining whether earlier surgery makes a difference in outcome in terms of urinary function once cauda equina syndrome (CES) from a herniated lumbar disc has progressed to urinary retention (CESR).MethodsLiterature search identified 27 studies of CESR patients with clear definition of surgical timing. Relative risk (RR) could not be calculated in 11 studies, leaving 16 for meta-analysis. Urinary retention related to surgical timing at 5 breakpoints: 12, 24, 36, 48, or 72 hours. Urinary outcome was classified as Normal, Fair, or Poor. Meta-analysis was performed for “Event = Fair/Poor” or “Event = Poor.” Eight studies allowed separation into CESR and incomplete CES (CESI), and 5 of these had enough data for meta-analysis to compare CESR and CESI. A random effects meta-analysis model was used because of heterogeneity across the studies. A best-evidence synthesis was performed for the 4 largest studies that had 24- and 48-hour breakpoints.ResultsFor “Event = Fair/Poor,” meta-analyses using the 5 breakpoints predicted a more likely Fair/Poor outcome for later surgery (RR range 1.77–2.19). The RR for later timing of surgery was statistically significant for 24-and 72-hour breakpoints and was elevated but not statistically significant for the other 3. For “Event = Poor,” the RR range was 1.09–5.82, statistically significant for the 36 hour breakpoint only. Meta-analysis comparing CESR patients with CESI patients predicted a Fair/Poor result for CESR (RR 2.58, 95% confidence interval 0.59–11.31). The best-evidence synthesis did not disclose reasons for differences in the results of the 4 studies.ConclusionsThis study supports early surgery for CES and indicates that CESR and CESI cases should not be analyzed together.
Nineteen out of 23 middle cerebral arterial specimens had as the first major branch of the middle cerebral artery a sizable anterior temporal artery; a trunk forming the anterior and middle temporal branches; a trunk forming the anterior, middle, and posterior temporal arteries; or a trunk forming temporal and angular arterial branches.
Patients harboring middle cerebral stenoses or occlusions who have correlating cerebral ischemic symptoms may be considered as candidates for microsurgical cerebral revascularization. However, if such patients undergo intracranial surgery, the superficial temporal artery should probably be joined to a supra-Sylvian arterial branch, rather than to a temporal arterial branch, in order to avoid delivering the new blood supply proximal to the stenotic or occluded segment.
The vulnerability of as-welded or improperly heat-treated unstabilized austenitic stainless steels to intergranular corrosion in certain types of corrosive media is well known. Several laboratory testing methods have been developed which have been employed for detecting susceptibility to intergranular corrosion. The use of such evaluation procedures permits prediction in advance as to whether or not the material represented by the test specimen will fail through intergranular corrosion when in service environments capable of attacking susceptible material in this manner. The three principal methods currently employed are the boiling 65 per cent nitric acid test, the acidified copper sulfate solution test, and the nitric-hydrofluoric acid test.
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