Table 3. AMSTAR ratings for included reviews.
| reference, year | AMSTAR questions1 | total Yes | overall quality2 | ||||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | |||
| exercise treatments: | |||||||||||||
| [51], 2003 (1/3)3 | N | CA | Y | N | N | Y | Y | Y | N | N | N | 4 | low |
| [52], 2008 (2/3)3 | Y | CA | Y | N | N | Y | Y | Y | Y | N | N | 6 | moderate |
| [53], 2011 (3/3)3 | Y | CA | N | N | N | Y | N4 | N5 | N | N | N | 2 | low |
| [54], 2012 | N | CA6 | N | N | N | Y | N | N | N | N | N | 1 | low |
| [33], 2012 | Y | Y | Y | Y | Y | Y | Y | Y | Y | N | N | 9 | high |
| manual therapy: | |||||||||||||
| [6], 2008 | N | CA | Y | N | N | Y | N | N5 | N | N | N | 2 | low |
| [55], 2012 | N | CA | Y7 | N | N | Y | Y | N8 | NA9 | N | N | 3 | low |
| [56], 2013 | N | Y | N | N | N | Y | Y10 | Y | N | N | N | 4 | low |
| [7], 2013 | N | Y | Y | N | N | Y | Y | Y | Y | N | Y | 7 | moderate |
| bracing: | |||||||||||||
| [25], 2007 | N | N | Y | N | N | Y | N | N5 | N | N11 | N | 2 | low |
| [16], 2010 | Y | Y | Y | Y | Y | Y | Y | Y | Y | N | N | 9 | high |
| [57], 2011 | N | CA | N | N | N | Y | Y | Y | N | N | N | 3 | low |
| [43] 12, 2011 | N | CA | CA13 | N | N | Y | N | N5 | Y | N | N | 212 | low12 |
| [36], 2012 | N | CA | N | N | N | N | N | N | N | N | N | 0 | low |
| different combinations of non-surgical interventions: | |||||||||||||
| [58], 1991 | N | Y | N | N | N | Y | Y | Y | N | N | N | 4 | low |
| [26], 1997 | N | CA14 | N | N15 | Y | N16 | N | N | Y | N | N | 2 | low |
| [37], 2005 | N | Y | N17 | N | N | Y | Y | Y | Y | N | N | 5 | moderate |
| [17], 2008 | N | N | Y | N | N | N | N | N | N | N | N | 1 | low |
| usual physical activity: | |||||||||||||
| [59], 2009 | N | Y | Y | Y | N | Y18 | N | N5 | N | N | N | 4 | low |
| adverse effects: | |||||||||||||
| [60], 2008 | N | CA19 | Y | N | N | Y | N | N | Y | N | N | 3 | low |
| [61], 2011 | N | Y | Y | N | N | N20 | N | N | N | N | N | 2 | low |
Y – yes, N – no, CA – cannot answer, NA – not applicable
questions [44], [46]: “1. Was an a priori design provided?, 2. Was there duplicate study selection and data extraction?, 3. Was a comprehensive literature search performed?, 4. Was the status of publication (i.e. grey literature) used as an inclusion criterion?, 5. Was a list of studies (included and excluded) provided? 6. Were the characteristics of the included studies provided?, 7. Was the scientific quality of the included studies assessed and documented?, 8. Was the scientific quality of the included studies used appropriately in formulating conclusions?, 9. Were the methods used to combine the findings of studies appropriate?, 10. Was the likelihood of publication bias assessed?, 11. Were potential conflicts of interest included?”; 2scores of 0–4 indicate that the review is of low quality, 5–8 of moderate quality and 9–11 of high quality [44]; 3the 2003 review and two updates; the reviews differed in methodology, thus analysed, as explained in Tables 1 and S2; 4one new study added and its quality not assessed; 5limitations of the included studies are reported, but item 8 cannot be scored “Y” if item 7 is scored “N”; 6methods of data extraction not reported; 7minimal criteria for a “Y” met, though hand searching was limited to reference lists of two reviews published at least 2 years earlier; 8quality of the included RCT in AIS patients was assessed, but not used in formulating conclusions; 9the review addresses different conditions and different outcomes; 10we gave a “Y”, but only 4 out of 10 included studies were assessed with a methodological quality tool (PEDro scale); all 10 papers were classified with levels of evidence; 11could not score a “Y” if no formal assessment of heterogeneity performed (despite narrative descriptions of potential sources of heterogeneity between the studies); 12the paper states that “the details regarding the methodology can be found in the web appendix at www.aospine.org/esbj”; however, the website does not offer access to that appendix; when the publisher’s website was browsed the paper was not supplemented with an appendix from that site (http://www.thieme.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=965&category_id=65&option=com_virtuemart&Itemid=53); similarly, the PubMed Central full text access is not supplemented with an appendix; finally, the first author was asked for this content, and, in reply, supplied the authors with a copy of the full text paper, and informed that the paper itself contains the information on methodology; thus, the AMSTAR analysis of the paper conducted without considering the appendix. 13 keywords and/or search strategy not available; 14three reviewers performed data extraction but it is not reported whether they worked independently; 15a thesis and unpublished report were included but they were not retrieved through searching for gray literature; 16some data from individual studies are provided, but description of participants and outcomes is lacking; 17the review meets the criterion of searching at least two sources, years and databases are reported, but there is no information on supplementary strategy (e.g. consulting current contents, textbooks, experts, reviewing reference lists [46]; 18scored a “Y” as included primary studies were characterised – the authors also included narrative reviews, which could not be characterised in terms of study participants or methodology; 19unclear whether one or more people independently conducted study search and selection process; 20this study was an extremely poor study which was very difficult to make sense of