***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: Ketamine may prevent postoperative hyperalgesia . In patients undergoing arthroscopic meniscectomy using general anesthesia , we tested whether a single intraoperative dose of ketamine enhanced postoperative analgesia and improved functional outcome compared with a typical multimodal analgesic regimen . After the induction of anesthesia , 50 patients were r and omly assigned to ketamine ( 0.15 mg/kg IV just after the induction of anesthesia ) or a vehicle placebo . St and ardized general anesthesia included propofol , alfentanil , and nitrous oxide . Bupivacaine ( 0.5 % ) and morphine ( 5 mg ) were given intraarticularly at the end of surgery . Postoperative analgesia was initially provided with morphine and subsequently with naproxen sodium ( 550 mg orally twice daily ) and Di-Antalvic ® ( 400 mg acetaminophen and 30 mg dextropropoxyphene ) as needed . Pain scores , analgesic requirements , side effects , and ability to walk were assessed in the ambulatory unit and at home for three postoperative days . Times to awakening and to discharge were similar in the two groups . However , the Ketamine group had significantly less postoperative pain at rest and during mobilization on Days 0 , 1 , and 2 . Furthermore , they consumed significantly fewer Di-Antalvic ® tablets than the control group ( 13 [ 7–17 ] vs 27 [ 16–32 ] , median [ 25%–75 % interquartile range ] ) . Patients given ketamine were also able to walk for longer periods of time on the first postoperative day . In conclusion , adding small-dose ketamine to a multimodal analgesic regimen improved postoperative analgesia and functional outcome after outpatient knee arthroscopy Background Postamputation pain is highly prevalent after limb amputation with neuropathic nature ;  calcitonin may effectively relieve many neuropathic pain states . Design Double-blind r and omized multicenter study . Setting Our study hypothesis is to evaluate the preventive value of epidural calcitonin on postoperative pain , grade of phantom pain , and the development of allodynia and hyperalgesia in patients undergoing lower limb amputation . Patients A cohort of 60 diabetic patients of both genders suffering from vascular insufficiency of one or both lower limbs underwent minor or major lower limb amputation . Patients were divided r and omly into two equal groups : an epidural bupivacaine-calcitonin-fentanyl ( BCF ) group and a bupivacaine-fentanyl ( BF ) group . Methods Patients were instructed about the use of a 10 cm visual analog scale ( VAS ) . Phantom limb pain was grade d using a four- grade scale . Pin-prick hyperalgesia and allodynia were evaluated at one week , one month , three months , and six months after surgery . Results There were no significant differences between groups regarding patients ' characteristics . There was no significant difference in the VAS scale between groups . There was statically significant improvement in the grade of phantom pain in the BCF group at six and 12 months after surgery ( P = 0.033 and 0.001 , respectively ) . A significantly higher number of patients developed allodynia in the BF group at six ( P = 0.039 ) and 12 ( P = 0.013 ) months and hyperalgesia at 12 months ( P = 0.025 ) . Conclusion The preventive use of epidural calcitonin improved the grade of phantom pain and reduced the incidence of allodynia and hyperalgesia in patients undergoing lower limb amputation under combined spinal-epidural anesthesia during one year of follow-up Overwhelming evidence shows the quality of reporting of r and omised controlled trials ( RCTs ) is not optimal . Without transparent reporting , readers can not judge the reliability and validity of trial findings nor extract information for systematic review s. Recent method ological analyses indicate that inadequate reporting and design are associated with biased estimates of treatment effects . Such systematic error is seriously damaging to RCTs , which are considered the gold st and ard for evaluating interventions because of their ability to minimise or avoid bias . A group of scientists and editors developed the CONSORT ( Consoli date d St and ards of Reporting Trials ) statement to improve the quality of reporting of RCTs . It was first published in 1996 and up date d in 2001 . The statement consists of a checklist and flow diagram that authors can use for reporting an RCT . Many leading medical journals and major international editorial groups have endorsed the CONSORT statement . The statement facilitates critical appraisal and interpretation of RCTs . During the 2001 CONSORT revision , it became clear that explanation and elaboration of the principles underlying the CONSORT statement would help investigators and others to write or appraise trial reports . A CONSORT explanation and elaboration article was published in 2001 alongside the 2001 version of the CONSORT statement . After an expert meeting in January 2007 , the CONSORT statement has been further revised and is published as the CONSORT 2010 Statement . This up date improves the wording and clarity of the previous checklist and incorporates recommendations related to topics that have only recently received recognition , such as selective outcome reporting bias . This explanatory and elaboration document-intended to enhance the use , underst and ing , and dissemination of the CONSORT statement-has also been extensively revised . It presents the meaning and rationale for each new and up date d checklist item providing examples of good reporting and , where possible , references to relevant empirical studies . Several examples of flow diagrams are included . The CONSORT 2010 Statement , this revised explanatory and elaboration document , and the associated website ( www.consort-statement.org ) should be helpful re sources to improve reporting of r and omised trials The objective of this study was to assess the effectiveness of a previously described technique of regional analgesia ( continuous infusion of local anesthetic through a catheter placed at the time of amputation within the exposed sciatic or posterior tibial nerve ) on relieving the postoperative pain in a heterogeneous group of patients who underwent lower extremity amputations . A second objective was to determine the effect of such treatment on the incidence and characteristics of phantom limb pain 6 months or more after surgery in the same patients . The study design was retrospective , unblinded , controlled ( postoperative pain ) , and unblinded question naire and interview ( phantom pain ) were utilized . Subjects were in patients at Harborview Medical Center , University of Washington , Seattle , WA . Nineteen bupivacaine-treated and 40 nonbupivacaine-treated patients who underwent lower extremity amputation subsequent to trauma , infection , long-st and ing injury ( poor or no function ) , congenital deformity , or burns were evaluated in the postoperative pain management assessment . Nine treated and 12 untreated patients were interviewed in the phantom pain assessment . Bupivacaine 0.5 % 2 - 6 ml/h was infused through a polyamide 20-gauge catheter inserted into the sciatic or posterior tibial nerve sheath under direct vision at the time of surgery . All patients , treated and control , received opioid analgesics systemically during the 72-hour period of study . The postoperative opioid analgesic requirement of treated patients was compared with that of control patients who received opioid analgesics alone . A question naire was administered to assess presence , severity , and character of phantom pain . ( ABSTRACT TRUNCATED AT 250 WORDS UNLABELLED Although previous research suggests that preamputation pain is a risk factor for pain after amputation , little is known about the association between acute postsurgical pain and chronic amputation-related pain . The current prospect i ve study examined the associations of preamputation pain and acute postamputation pain with chronic amputation-related pain . The sample consisted of patients with lower limb amputation ( N = 57 ) who provided both preamputation and postamputation data during a 2-year study period .  Preamputation pain intensity and duration  were assessed before  amputation ; acute phantom limb pain ( PLP ) and residual limb pain ( RLP ) intensity were assessed on postsurgical days 4 and 5 . Acute PLP intensity was the only significant independent predictor of chronic PLP intensity at 6 and 12 months after amputation , whereas preamputation pain intensity was the only significant predictor of chronic PLP intensity at 24 months . Similarly , acute RLP was found to be the best overall predictor of chronic RLP . Other variables ( age , gender , level and etiology of amputation , amount of postsurgical pain medication , and duration of preamputation pain ) were not associated with chronic pain . These results suggest that higher levels of pain either before or soon after amputation might help to identify individuals at greatest risk for chronic pain problems and most in need of early , intensive pain interventions . PERSPECTIVE This study suggests that both preamputation pain and acute pain soon after amputation might be associated with bothersome chronic pain . The results support further research on acute pain mechanisms and the effectiveness of early interventions aim ed at preventing or managing amputation-related pain BACKGROUND : Recently , a prediction rule was developed to preoperatively predict the risk of severe pain in the first postoperative hour in surgical in patients . We aim ed to modify the rule to enhance its use in both surgical in patients and out patients ( ambulatory patients ) . Subsequently , we prospect ively tested the modified rule in patients who underwent surgery later in time and in another hospital ( external validation ) . METHODS : The rule was originally developed from the data of 1395 adult in patients . We modified the rule with the data of 549 out patients who underwent surgery between 1997 and 1999 in the same center ( Academic Medical Center Amsterdam , The Netherl and s ) . Furthermore , we tested the performance of the modified rule in 1035 in- and out patients who underwent surgery in 2004 , in the University Medical Center Utrecht , The Netherl and s ( external validation ) . Performance was quantified by the rule 's calibration ( agreement between observed frequencies and predicted risks ) and discrimination ( ability to distinguish between patients at high and low risk ) . RESULTS : Modification of the original rule to enhance prediction in out patients included reclassification of the predictor “ type of surgery , ” addition of the predictor “ surgical setting ” ( ambulatory surgery : yes/no ) and addition of interaction terms between surgical setting and the other predictors . One-third of the patients in the Utrecht cohort reported severe postoperative pain ( 36 % ) , compared to 62 % of the patients in the Amsterdam cohort . The distribution of most predictors was similar in the two cohorts , although the patients in the Utrecht cohort were slightly older , more often underwent ambulatory surgery and had large expected incision sizes less often than patients in the Amsterdam cohort . The modified prediction rule showed good calibration , when an adjusted intercept was used for the lower incidence in the Utrecht cohort . The discrimination was reasonable ( area under the Receiver Operating Characteristic curve 0.65 [ 95 % confidence interval 0.57–0.73 ] ) . CONCLUSIONS : A previously developed prediction rule to predict severe postoperative pain was modified to allow use in both in patients and out patients . By validating the rule in patients who underwent surgery several years later in another hospital , it was shown that the rule could be generalized in time and place . We demonstrated that , instead of deriving new prediction rules for new population s , a simple adjustment may be enough to recalibrate prediction rules for new population s. This is in line with the perception that external validation and updating of prediction rules is a continuing and multistage process Objective . The pathogenesis and risk of chronic pain after cholecystectomy are unknown . In this prospect i ve study of 150 consecutive patients undergoing laparoscopic cholecystectomy  , the preoperative clinical data , cold pressor test , state of neuroticism and early postoperative pain intensity were assessed . Material and methods . Follow-up question naires were sent to all patients 1 year after surgery . Patients with moderate/severe chronic pain were interviewed and invited to participate in a structured examination programme . Results . The question naire response rate was 100 % . Twenty patients reported moderate or severe chronic pain . The 1-year in-office interview revealed that two patients without chronic pain had misinterpreted the question naire . Sixteen patients were enrolled for the examination programme . Demonstrable pathology explained the aetiology of chronic pain in 8 patients ( 5 % ) ; another 8 patients with moderate ( n=6 ) or severe ( n=2 ) chronic pain were without pathological findings . In total , 132 patients had no chronic pain . Chronic pain patients suffered significantly more intense acute postoperative pain compared with those without chronic pain ( p≤0.05 ) . The incidence of chronic pain patients was higher in the group of patients with intense acute postoperative pain than in patients with low acute postoperative pain ( p = 0.030–0.063 ) . Development of chronic pain was not statistically related to a preoperative cold pressor nociceptive stimulus , preoperative state of neuroticism or to any other variables examined . Conclusions . The risk of significant chronic pain after laparoscopic cholecystectomy for symptomatic cholecystolithiasis is low but was significantly associated with the intensity of acute postoperative pain . Patients should be carefully examined to exclude somatic causes of chronic pain after laparoscopic cholecystectomy Postamputation pain ( PAP ) is highly prevalent after limb amputation but remains an extremely challenging pain condition to treat . A large part of its intractability stems from the myriad pathophysiological mechanisms . A state-of-art underst and ing of the pathophysiologic basis underlying postamputation phenomena can be broadly categorized in terms of supraspinal , spinal , and peripheral 
    Output:
    
Based on five RCTs ( n=268 ) and two observational studies ( n=49 ) , epidural analgesia decreased the intensity of acute stump pain as compared to systemic analgesics , during the first 24 h after the operation .
Based on one RCT ( n=21 ) and eight observational studies ( n=501 ) CPI seemed to decrease opioid consumption as compared to systemic analgesics only , on the first three postoperative days , and was well tolerated .
Ketamine did not decrease acute pain or opioid consumption after amputation as compared to other systemic analgesics .
Gabapentin did not decrease acute pain when combined to epidural analgesia as compared to epidural analgesia and opioid treatment , and caused adverse effects .
Conclusions : The main finding of this systematic review is that evidence regarding pain management after major limb amputation is very limited .
Epidural analgesia may be effective , but firm evidence is lacking .
Epidural causes more adverse effects than CPI .