This small, pilot study suggests that isoflurane may be more commonly associated with post-operative cognitive dysfunction than desflurane in older patients.
Nice summary, seems like common sense with very useful number needed to harm data, though from personal experience surprising the NNH for itching was lower for Fentanyl than Morpine
In the publicly available version no mention of risks. Locally this technique was popular a while ago but abandonded after a few total spinals and such