Listening to music before, during, or after a surgical procedure is beneficial to patients and can significantly reduce pain and anxiety, and decrease the need for pain medication, according to the most comprehensive review of the evidence so far, involving almost 7000 patients, published in The Lancet.
A team of UK researchers from Brunel University and Queen Mary University of London conducted a systematic review and meta-analysis of all published randomised trials examining the impact of music compared with standard care or other non-drug interventions (eg, massage and relaxation) on postoperative recovery in adult patients undergoing any form of surgical procedure.
Analysis of data from 72 trials involving nearly 7000 patients found that patients were significantly less anxious after surgery (standardised mean difference from the start of the study [SMD] -0.68 ) and reported significantly more satisfaction (SMD 1.09) after listening to music (figure 3). They also needed less pain medication (SMD -0.37) and reported significantly less pain (SMD -0.77) compared with controls. Listening to music at any time seemed effective, although there was a trend for better outcomes if patients listened to music before surgery rather than during or after.
What is more, when patients selected their own music there was a slightly greater (but non-significant) reduction in pain and use of pain relief (figure 3).
Surprisingly, even listening to music while under general anaesthetic reduced patients' levels of pain, although the effects were larger when patients were conscious. However, music did not reduce length of hospital stay.
According to lead author Dr Catherine Meads from Brunel University, "More than 51 million operations are performed every year in the USA and around 4.6 million in England. Music is a non-invasive, safe, cheap intervention that should be available to everyone undergoing surgery. Patients should be allowed to choose the type of music they would like to hear to maximise the benefit to their wellbeing. However, care needs to be taken that music does not interfere with the medical team's communication." 
Writing in a linked Comment, Dr Paul Glasziou from Bond University, Queensland, Australia says, "Music is a simple and cheap intervention, which reduces transient discomforts for many patients undergoing surgery. A drug with similar effects might generate substantial marketing...The very high heterogeneity...of effects among trials in the accompanying study highlights a research opportunity--to identify how to maximise the effect."
NOTES TO EDITORS:
 The standardised mean difference is used in systematic reviews and meta-analyses when the studies all assess the same outcome but measure it in a variety of ways (for example, all studies measured anxiety but they used different psychometric scales). Therefore, it is necessary to standardise the results of the studies to a uniform scale before they can be combined.
 Quote direct from author and cannot be found in text of Article.