R软件网状meta节点劈裂法不一致性检验报错

R语言行网状meta分析，有闭合环，节点劈裂法检验不一致性。

执行mtc.nodesplit.comparisons(network)命令后出现错误提醒，如下：

<0 行> (或0-长度的row.names)

> mtc.nodesplit(network, comparisons=mtc.nodesplit.comparisons(network))

Error in mtc.nodesplit(network, comparisons = mtc.nodesplit.comparisons(network)) : 

 There are no comparisons to assess for inconsistency. See https://doi.org/10.1002/jrsm.1167 for how this is determined.

求大神赐教，不甚感激