***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: We identified seven studies that met inclusion criteria for this review. Three were recorded as completed (or terminated) but no results were published. Of the remaining four studies (299 participants): two investigated liposomal bupivacaine transversus abdominis plane (TAP) block, one liposomal bupivacaine dorsal penile nerve block, and one ankle block. The study investigating liposomal bupivacaine ankle block was a Phase II dose-escalating/de-escalating trial presenting pooled data that we could not use in our analysis. The studies did not report our primary outcome, cumulative pain score between 0 and 72 hours, and secondary outcomes, mean pain score at 12, 24, 48, 72, or 96 hours. One study reported no difference in mean pain score during the first, second, and third postoperative 24-hour periods in participants receiving liposomal bupivacaine TAP block compared to no TAP block. Two studies, both in people undergoing laparoscopic surgery under TAP block, investigated cumulative postoperative opioid dose, reported opposing findings. One found a lower cumulative opioid consumption between 0 and 72 hours compared to bupivacaine hydrochloride TAP block and one found no difference during the first, second, and third postoperative 24-hour periods compared to no TAP block. No studies reported time to first postoperative opioid or percentage not requiring opioids over the initial 72 hours. No studies reported a health economic analysis or patient-reported outcome measures (outside of pain). The review authors sought data regarding adverse events but none were available, however there were no withdrawals reported to be due to adverse events. Using GRADE, we considered the quality of evidence to be very low with any estimate of effect very uncertain and further research very likely to have an important impact on our confidence in the estimate of effect. All studies were at high risk of bias due to their small sample size (fewer than 50 participants per arm) leading to uncertainty around effect estimates. Additionally, inconsistency of results and sparseness of data resulted in further downgrading of the quality of the data. A lack of evidence has prevented an assessment of the efficacy of liposomal bupivacaine administered as a peripheral nerve block. At present there is a lack of data to support or refute the use of liposomal bupivacaine administered as a peripheral nerve block for the management of postoperative pain. Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Output:

In January 2016, we found seven studies that assessed liposomal bupivacaine nerve block. Three studies were listed as completed but had not reported results. This left four studies involving 299 participants for this review. Two studies investigated liposomal bupivacaine given between two of the layers of abdominal muscles to block the nerves supplying sensation to that area (known as a transversus abdominus plane (TAP) block); one study investigated liposomal bupivacaine given around the nerves that supply sensation to the penis (dorsal penile nerve block); and one study investigated the ankle (ankle block). We did not identify any studies that reported our primary outcome cumulative pain score between 0 and 72 hours or pain-centred secondary outcomes. Two studies reported cumulative opioid (a strong painkiller) use with inconsistent results. We looked for results about side effects but none were reported, however no participants dropped out of the studies due to side effects. Overall, the lack of evidence, due to the small number of trials each reporting different outcomes, prevented a full assessment of the role of liposomal bupivacaine administered as a nerve block for the management of pain after surgery in adults. Due to the small number of trials, and small number of participants in these trials, the quality of evidence was very low. As such, further research is required to evaluate the role of liposomal bupivacaine as a nerve block to treat pain after surgery.