Curtis Brown

Systematic review of observational studies reveals no association between low back pain and lumbar spondylolysis with or without isthmic spondylolisthesis

PurposeThe hypothesis that spondylolysis (SL) and/or isthmic spondylolisthesis (IS) cause low back pain (LBP) is widely accepted representing surgical indication in symptomatic cases. If SL/IS cause LBP, individuals with these conditions should be more prone to LBP than those without SL/IS. Therefore, the goal of the study was to assess whether the published primary data demonstrate an association between SL/IS and LBP in the general adult population.MethodsSystematic review of published observational studies to identify any association between SL/IS and LBP in adults. The methodological quality of the cohort and case–control studies was evaluated using the Newcastle-Ottawa scale.ResultsFifteen studies met inclusion criteria (one cohort, seven case–control, seven cross-sectional). Neither the cohort study nor the two highest-quality case–control studies detected an association between SL/IS and LBP; the same is true for the remaining studies.ConclusionsThere is no strong or consistent association between SL/IS and LBP in epidemiological studies of the general adult population that would support a hypothesis of causation. It is possible that SL/IS coexist with LBP, and observed effects of surgery and other treatment modalities are primarily due to benign natural history and nonspecific treatment effects. We conclude that traditional surgical practice for the adult general population, in which SL/IS is assumed to be the cause of non-radicular LBP whenever the two coexist, should be reconsidered in light of epidemiological data accumulated in recent decades.

The necessary a posteriori: A response to Tichý

ConclusionSome of Tichýs conclusions rest on an assumption about substitutivity which Kripke would not accept. If we grant the assumption, then Tichý successfully shows that we can discover true identity statements involving names a priori, but not that we can discover a priori what properties things have essentially. Many of Tichýs arguments require an implausible rejection of the possibility of indirect belief as described in Section III. 25Are there necessary a posteriori propositions? I have argued that we certainly can discover necessary propositions a posteriori, but have left it an open question whether there are necessary propositions which we can only discover a posteriori.What effect do the considerations here presented have on the positivist doctrine that the a priori and the necessary coincide? My explanation of how we discover necessary propositions a posteriori involves our believing them indirectly, in virtue of believing contingent propositions. I would argue that Kripkes examples of the contingent a priori involve, similarly, our believing the contingent propositions in directly, in virtue of believing necessary propositions.This suggests that a reformulation of the positivist thesis along something like the following lines may well be correct. Let us say that someone directly believes a proposition just in case he could not fail to believe it without being in a different cognitive state. Then perhaps one can directly believe a proposition on the basis of a priori evidence only if it is necessary, and can directly believe a proposition on the basis of a posteriori evidence only if it is contingent.