***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 
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    ***EXAMPLES*** 
    Input: BACKGROUND Pain control after thoracotomy prevents postsurgical complications and improves respiratory function . The gold st and ard for post-thoracotomy analgesia is the epidural catheter . The aim of this study was to compare it with a new technique that involves placement of a catheter in the paravertebral space at the end of surgery under a surgeon 's direct vision . METHODS From November 2011 to June 2012 , 52 patients were r and omized into 2 groups depending on catheter placement : an epidural catheter for group A and a paravertebral catheter for group B. At 12 , 24 , 48 , and 72 hours after surgery , the following parameters were recorded : ( 1 ) pain control using the patient 's completion of a visual analog scale module , ( 2 ) respiratory function using forced expiratory volume in 1 second and ambient air saturation , and ( 3 ) blood cortisol values as an index of systemic reaction to pain . RESULTS Statistically significant differences ( P < .05 ) were found in favor of group B for both cough and rest pain control ( P = .002 and .002 , respectively ) and respiratory function in terms of forced expiratory volume in 1 second and ambient air saturation levels ( P = .023 and .001 , respectively ) . No statistically significant differences were found in blood cortisol trends between the 2 groups ( P > .05 ) . Collateral effects such as vomiting , nausea , low pressure , or urinary retention were observed only in group A. No collateral effects were recorded in the paravertebral group . CONCLUSIONS According to our data , drugs administered through a paravertebral catheter are very effective . Moreover , it does not present contraindications to its positioning or collateral effects . More studies are necessary to confirm data we collected AIM Epidural analgesia is considered to be the best method of pain relief after major surgery despite its side-effects , which include hypotension , respiratory depression , urinary retention , incomplete or failed block , and , in rare cases , paraplegia . Paravertebral block is an alternative technique that may offer a comparable analgesic effect and a better side-effect profile . This study measured postoperative pain and respiratory function in patients r and omized to receive either paravertebral block or epidural analgesia for pain control after thoracic surgery . METHODS Twenty-four adult patients undergoing thoracic surgery were enrolled in a prospect i ve and r and omized clinical study . Patients were r and omly allocated to receive either postoperative continuous paravertebral analgesia ( N=12 ) or epidural analgesia ( N=12 ) starting at pleura closure . Postoperative use of morphine , visual analogue scores , and spirometer data were collected for 72 hours after surgery as markers of pain relief . RESULTS There was a statistically significant ( P=0.003 ) increase in median ( 25th-75th percentiles ) patient-controlled use of morphine , with values of 36 ( 22 - 42 ) mg in the paravertebral group vs. 9 ( 2 - 22 ) mg in the epidural group . This increase in morphine usage in the paravertebral group was statistically significant at 6 , 24 , 48 , and 72 hours after surgery . Postoperative pain measured with the visual analogue score was not significantly different in the two groups . Spirometer values at 72 h were better in the epidural group than in the paravertebral group ( P=0.03 ) . CONCLUSIONS Epidural analgesia is more efficient than paravertebral continuous block at reducing pain after thoracic surgery OBJECTIVE To compare the results of continuous epidural bupivacaine analgesia with and without hydromorphone to continuous paravertebral analgesia with bupivcaine in patients with post-thoracotomy pain . DESIGN A prospect i ve , r and omized , double-blinded trial . SETTING A teaching hospital . PARTICIPANTS Patients at a tertiary care teaching hospital undergoing throracotomy for lung cancer . INTERVENTIONS Subjects were assigned r and omly to receive a continuous thoracic epidural or paravertebral infusion . Patients in the epidural group were r and omized to receive either bupivacaine alone or in combination with hydromorphone .  Visual analog scores as well as incentive spirometery results were obtained before and after thoracotomy . METHODS AND MAIN RESULTS Seventy-five consecutive patients presenting for thoracotomy were enrolled in this institutional review board-approved study . On the morning of surgery , subjects were r and omized to either an epidural group receiving bupvicaine with and without hydromorphone or a paravertebral catheter-infused bupvicaine .  Postoperative visual analog scores and incentive spirometry data were measured in the postanesthesia care unit , the evening of the first operative day , and daily thereafter until postoperative day 4 . Analgesia on all postoperative days was superior in the thoracic epidural group receiving bupivacaine plus hydromorphone .  Analgesia was similar in the epidural and continuous paravertebral groups receiving bupivacaine alone . No significant improvement was noted by combining the continuous infusion of bupivacaine via the paravertebral and epidural routes . Incentive spirometry goals were best achieved in the epidural bupivacaine and hydromorphone group and equal in the group receiving bupivacaine alone either via epidural or continuous paravertebral infusion . CONCLUSIONS The current study provided data that fill gaps in the current literature in 3 important areas . First , this study found that thoracic epidural analgesia ( TEA ) with bupivacaine and a hydrophilic opioid , hydromorphone , may provide enhanced analgesia over TEA or continuous paravertebral infusion ( CPI ) with bupivacaine alone . Second , in the bupivacaine-alone group , the increased basal rates required to achieve analgesia result ed in hypotension more frequently than in the bupivacaine/hydromorphone combination group , underscoring the benefit of the synergistic activity . Finally , in agreement with previous retrospective studies , the current data suggest that CPI of local anesthetic appears to provide acceptable analgesia for post-thoracotomy pain Background : The aim of this prospect i ve , r and omized , blinded study was to compare analgesic efficacy of continuous paravertebral and epidural analgesia for  post‐thoracotomy pain . Methods : Forty‐two ASA physical status II – III patients undergoing lung resection surgery were r and omly allocated to receive post‐thoracotomy analgesia with either a thoracic epidural ( group EPI , n = 21 ) or paravertebral ( group PVB , n = 21 ) infusion of 0.2 % ropivacaine ( infusion rate : 5–10 mL h−1 ) . The degree of pain at rest and during coughing , haemodynamic variables and blood gas analysis were recorded every 12 h for the first 48 h. Results : The area under the curve of the visual analogue pain score during coughing over time was 192 ( 60–444 ) cm h−1 in group EPI and 228 ( 72–456 ) cm h−1 in group PVB ( P = 0.29 ) . Rescue morphine analgesia was required in four patients of group EPI ( 19 % ) and five patients of group PVB ( 23 % ) ( P = 0.99 ) . The PaO2/FiO2 ratio reduced significantly from baseline values in both groups without between‐group differences . The median ( range ) percentage reduction of systolic arterial pressure from baseline was −9 ( 0 to −9)% in group PVB and −17 ( 0 to −38)% in group EPI ( P = 0.02 ) ; while clinical ly relevant hypotension ( systolic arterial pressure decrease > 30 % of baseline ) was observed in four patients of group EPI only ( 19 % ) ( P = 0.04 ) . Patient satisfaction with the analgesia technique was 8.5 ( 8–9.8 ) cm in group EPI and 9 ( 7.5–10 ) cm in group PVB ( P = 0.65 ) . Conclusions : Continuous thoracic paravertebral analgesia is as effective as epidural blockade in controlling post‐thoracotomy pain , but is associated with less haemodynamic effects Context Thoracic epidural and paravertebral blocks provide adequate analgesia for postoperative thoracotomy pain . Both procedures are usually performed percutaneously with considerable failure rates . A subpleural catheter placed in the space posterior to the parietal pleura and alongside the paravertebral area may provide superior postoperative pain relief . Objective To compare subpleural analgesia with thoracic epidural analgesia in patients undergoing thoracotomy . Design R and omised , double-blind study . Setting A tertiary care University Medical Centre between 26 June 2008 and 21 March 2011 . Patients Forty-two patients scheduled for elective posterolateral thoracotomy . Patients with American Society of Anesthesiologists physical status ≥4 , with a previous history of thoracotomy , on chronic pain medications or with a contraindication to receiving local anaesthetics or thoracic epidural block were excluded from the study . Interventions Patients were r and omised to receive either subpleural analgesia or thoracic epidural analgesia for 24-h post-thoracotomy pain control . Main outcome measures A visual analogue scale was used to assess pain at rest and on coughing during the first 24 h postoperatively and the incidence of hypotension was recorded . Results Patients who received subpleural analgesia had higher visual analogue scores at rest and on coughing than those who received thoracic epidural analgesia . Seven patients who started with subpleural analgesia were treated with thoracic epidural analgesia at a mean ( SD ) of 3.9 ( 4.8 ) h. The remaining 14 patients had a median ( IQR [ range ] ) visual analogue score of 5 cm ( 4–5 [ 3–6 ] ) at rest and were maintained on subpleural analgesia until the end of the study . The visual analogue score at rest was < 7 cm in all 21 patients who received thoracic epidural analgesia and none was switched to subpleural analgesia during the study . None of the patients in the subpleural analgesia group experienced hypotension compared with five of the 21 patients in the thoracic epidural analgesia group ( P = 0.047 ) . Conclusion Thoracic epidural analgesia is superior to subpleural analgesia in relieving post-thoracotomy pain OBJECTIVE Long-term pain is a common sequela of thoracotomy , occurring in approximately 50 % of patients 2 years after thoracic surgery . Despite this alarming statistic , little is known about the factors responsible for the transition of acute to chronic pain . The aim of the present study is to identify predictors of long-term post-thoracotomy pain . DESIGN Follow-up was for 1.5 years for patients who had participated in a prospect i ve , r and omized , controlled trial of preemptive , multimodal analgesia .  SETTING Subjects were recruited from a tertiary care center . PATIENTS Thirty patients who had undergone lateral thoracotomy  were followed up by telephone , administered a structured interview , and classified according to long-term pain status . MAIN OUTCOME MEASURES Present pain status was measured by a verbal rating scale ( VAS ) . Measures obtained within the first 48 h after surgery were compared between patients with and without pain 1.5 years later . These include VAS pain scores at rest and after movement , McGill Pain Question naire data , patient-controlled morphine consumption ( mg ) , and pain thresholds to pressure applied to a rib contralateral to the thoracotomy incision . RESULTS Fifty-two percent of patients reported long-term pain . Early postoperative pain was the only factor that significantly predicted long-term pain . Pain intensity 24 h after surgery , at rest , and after movement was significantly greater among patients who developed long-term pain compared with pain-free patients . A significant predictive relationship was also found at 24 and 48 h using the McGill Pain Question naire . Cumulative morphine was comparable for the two groups . Pain thresholds to pressure applied to a rib contralateral to the incision did not differ significantly between the groups . CONCLUSION Aggressive management of early postoperative pain may reduce the likelihood of long-term post-thoracotomy pain Background In order to assess the short term risks of pneumonectomy for lung cancer in contemporary practice a one year prospect i ve observational study of pneumonectomy outcome was made . Current UK practice for pneumonectomy was observed to note patient and treatment factors associated with major complications . Methods A multicentre , prospect i ve , observational cohort study was performed . All 35 UK thoracic surgical centres were invited to su bmi t data to the study . All adult patients undergoing pneumonectomy for lung cancer between 1 January and 31 December 2005 were included . Patients undergoing pleuropneumonectomy , extended pneumonectomy , completion pneumonectomy following previous lobectomy and pneumonectomy for benign disease , were excluded from the study .The main outcome measure was suffering a major complication . Major complications were defined as : death within 30 days of surgery ; treated cardiac arrhythmia or hypotension ; unplanned intensive care admission ; further surgery or inotrope usage . Results 312 pneumonectomies from 28 participating centres were entered . The major complication incidence was : 30-day mortality 5.4 % ; treated cardiac arrhythmia 19.9 % ; unplanned intensive care unit ad 
    Output:
    
OBJECTIVES To compare the two regional techniques of TEB and PVB in adults undergoing elective thoracotomy  with respect to:1 .
AUTHORS ' CONCLUSIONS Paravertebral blockade reduced the risks of developing minor complications compared to thoracic epidural blockade .
Paravertebral blockade was as effective as thoracic epidural blockade in controlling acute pain .
There was a lack of evidence in other outcomes .
There was no difference in 30-day mortality , major complications , or length of hospital stay .