***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Patients with biliary obstruction due to malignant disease , and judged unfit for open operation , were r and omised to have a biliary stent inserted either endoscopically via the papilla of Vater or percutaneously . Analysis after 75 patients had been entered showed that the endoscopic method had a significantly higher success rate for relief of jaundice ( 81 % versus 61 % , p = 0.017 ) and a significantly lower 30-day mortality ( 15 % versus 33 % , p = 0.016 ) . The higher mortality after percutaneous stents was due to complications associated with liver puncture ( haemorrhage and bile leaks ) . When stenting is indicated in elderly and frail patients the endoscopic method should be tried first BACKGROUND The necessity for drainage of both liver lobes in tumors arising at the biliary bifurcation is controversial . The aim of this study was to compare the outcome of unilateral versus bilateral drainage in patients with biliary obstruction at the hilum . METHODS One hundred fifty-seven consecutive patients with primary cholangiocarcinoma , gallbladder cancer , or periportal lymph node metastases were r and omly allocated to unilateral ( group A ) or bilateral ( group B ) hepatic duct drainage . RESULTS In intention-to treat analysis , group A had a significantly higher rate of successful endoscopic stent insertion  than group B ( 88.6 % vs. 76.9 % , p = 0.041 ) . Group B had a significantly higher rate of complications than group A ( 26.9 % vs. 18.9 % , p = 0.026 ) because of the higher rate of early cholangitis ( 16.6 % vs. 8.8 % , p = 0.013 ) . In per- protocol analysis the rate of successful drainage , complications , and mortality did not differ between the two groups . Median survival did not differ between the two groups but was significantly different for patients with cholangiocarcinoma and those with gallbladder cancer versus patients with metastatic tumors ( p = 0.0247 ) . CONCLUSION The insertion of more than one stent would not appear justified as a routine procedure in patients with biliary bifurcation tumors The development of non-surgical techniques for the relief of malignant low bileduct obstruction has cast doubt on the best way of relieving jaundice , particularly in patients fit for surgery whose life expectancy is more than a few weeks . We did a r and omised prospect i ve controlled trial comparing endoscopic stent insertion and surgical biliary bypass in patients with malignant low bileduct obstruction . 204 patients were r and omised ( surgery 103 , stent 101 ) ; 3 subsequently proved to have benign disease and were excluded , leaving 101 surgical and 100 stented patients for assessment .  Technical success was achieved in 94 surgical and 95 stented patients , with functional biliary decompression obtained in 92 patients in both groups . In stented patients , there was a lower procedure-related mortality ( 3 % vs 14 % , p = 0.01 ) , major complication rate ( 11 % vs 29 % , p = 0.02 ) , and median total hospital stay ( 20 vs 26 days , p = 0.001 ) . Recurrent jaundice occurred in 36 stented patients and 2 surgical patients . Late gastric outlet obstruction occurred in 17 % of stented patients and 7 % of the surgical group . Despite the early benefits of stenting there was no significant difference in overall survival between the two groups ( median survival : surgical 26 weeks ; stented 21 weeks ; p = 0.065 ) . Endoscopic stenting and surgery are effective palliative treatments with the former having fewer early treatment-related complications and the latter fewer late complications 
    Output:
    
Bilateral metal stenting seems to have lower odds of overall complications when compared to unilateral metallic stenting .
Bilateral metal stents seem to have higher odds of lowering bilirubin than unilateral metal stents , but the 30-day mortality was no different .
For metal stents , bilateral metal stents are superior in palliating symptoms due to hyperbilirubinemia .
Unilateral plastic stenting seems to have similar odds of overall complications , cholangitis , and 30-day mortality when compared to bilateral plastic stenting for malignant hilar strictures .
In patients with malignant hilar stricture , unilateral plastic stenting is comparable to bilateral plastic stenting for adverse events