***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: Background : Nonsteroidal antiinflammatory drugs are commonly used to treat postoperative and chronic pain . Animal studies suggest that these drugs act , in part , by blocking prostagl and in production in the spinal cord . The authors tested intrathecal ketorolac in patients with chronic or postoperative pain . Methods : After approval of the institutional review board and the Food and Drug Administration , three clinical studies were performed . First , 15 patients receiving chronic intrathecal morphine  received 0.5–2.0 mg of intrathecal ketorolac . Second , 12 patients receiving chronic intrathecal morphine  received , in a double-blinded , r and omized , cross-over design , intrathecal saline or 2.0 mg of ketorolac , with pain intensity as the primary outcome measure . Third , 30 patients undergoing total vaginal hysterectomy received , in a double-blinded , r and omized , controlled design , intrathecal saline or 2.0 mg of ketorolac , with bupivacaine with time to first morphine dose after surgery as the primary outcome measure . Results : Patients with chronic pain had many symptoms before intrathecal injection , without worsening of these symptoms from ketorolac .  Pain intensity was reduced by intrathecal ketorolac , but this did not differ from placebo . In the first study , pain was reduced by intrathecal ketorolac in patients with high cerebrospinal fluid prostagl and in E2 concentrations but not in those with normal concentrations . Intrathecal ketorolac did not alter time to first morphine after surgery . Conclusions : Intrathecal ketorolac did not relieve chronic pain or extend anesthesia or analgesia from intrathecal bupivacaine administered at the beginning of surgery . Under the conditions of these studies , it seems that spinal cylcooxygenase activity does not contribute to chronic or postoperative pain The efficacy of bupivacaine instillation into preperitoneal space following laparoscopic herniorrhaphy for postoperative pain reduction is still in controversy . A r and omized controlled trial was conducted to determine the efficacy of bupivacaine instillation . The 40 patients , who had an inguinal hernia with no complication , unilateral or bilateral and recurrence or no recurrence after previous hernia repair , were r and omly assigned to receive bupivacaine ( n = 19 ) and normal saline ( n = 21 ) . The intervention or placebo was instilled into the preperitoneal space after total extraperitoneal laparoscopic herniorrhaphy .  Pain intensity was assessed by using a visual analogue scale and verbal rating scale after the 1st , 2nd , 6th , 12th , and 24th hour postoperatively . For the bupivacaine and placebo group , mean pain scores were 3.5 versus 5.2 ( P = .059 ) , 2.9 versus 4.5 ( P = .117 ) , 2.1 versus 3.2 ( P = .101 ) , 1.5 versus 2.7 ( P = .145 ) , and 1.6 versus 2.0 ( P = .672 ) after the 1st , 2nd , 6th , 12th , and 24th hour , respectively . Complications developed in 4 patients in the bupivacaine group and 7 patients in the placebo group after 3 months follow-up time . There is no strong evidence to confirm that bupivacaine instillation into preperitoneal space after laparoscopic herniorrhaphy can reduce postoperative pain Objective : To characterize the beneficial effects of perioperative systemic lidocaine on length of hospital stay , gastrointestinal motility , and the inflammatory response after colorectal surgery . Summary Background Data : Surgery-induced stimulation of the inflammatory response plays a major role in the development of several postoperative disorders . Local anesthetics possess anti-inflammatory activity and are thought to positively affect patients ' outcome after surgery . This double-blinded , r and omized , and placebo-controlled trial aim ed to evaluate beneficial effects of systemic lidocaine and to provide insights into underlying mechanisms . Methods : Sixty patients undergoing colorectal surgery , not willing or unable to receive an epidural catheter , were r and omly assigned to lidocaine or placebo treatment . Before induction of general anesthesia , an intravenous lidocaine bolus ( 1.5 mg/kg ) was administered followed by a continuous lidocaine infusion ( 2 mg/min ) until 4 hours postoperatively . Length of hospital stay , gastrointestinal motility , and pain scores were recorded and plasma levels or expression of pro- and anti-inflammatory mediators determined . Results : Lidocaine significantly accelerated return of bowel function and shortened length of hospital stay by one day . No difference could be observed in daily pain ratings . Elevated plasma levels of IL-6 , IL-8 , complement C3a , and IL-1ra as well as expression of CD11b , l- and P-selectin , and platelet-leukocyte aggregates were significantly attenuated by systemic lidocaine . Conclusions : Perioperative intravenous lidocaine not only improved gastrointestinal motility but also shortened length of hospital stay significantly . Anti-inflammatory activity modulating the surgery-induced stress response may be one potential mechanism . Systemic lidocaine may thus provide a convenient and inexpensive approach to improve outcome for patients not suitable for epidural anesthesia OBJECTIVES To test the hypotheses that lidocaine 5 % patches decrease the severity of acute pain and incidence of persistent incisional pain after robotic cardiac valve surgery . DESIGN A r and omized , placebo-controlled , double-blind trial . SETTING Tertiary care academic medical center . SUBJECTS Patients having robotic cardiac valve surgery . METHODS Patients having robotic cardiac valve surgery were r and omly assigned to 5 % lidocaine patches or identical-appearing placebo patches . Patches were applied around each incision 12 hours/day until pain resolved , or for 6 months . Supplemental opioid was provided by patient-controlled analgesia or orally . Pain was initially evaluated with a Visual Analog Scale , and subsequently by telephone with a Verbal Response Scale and the Pain Disability Index ( our primary outcome ) after 1 week , 1 month , 3 months , and 6 months . Global Perceived Effect , a measure of patient satisfaction , was simultaneously recorded . Repeated- measures analysis of variance and generalized estimating equations were our primary statistical tools . RESULTS Acute pain scores and opioid use were low , as was the incidence of persistent pain .  Lidocaine 5 % patches did not influence any measure of acute or persistent incisional pain . Estimated difference ( 95 % CI ) in mean Pain Disability Index for Lidocaine patch minus placebo was -2.5 ( 95 % CI -7.1 , 2.1 ) , P = 0.28 . CONCLUSIONS Lidocaine 5 % patches did not reduce acute or persistent pain in patients having robotic thoracic surgery , though pain scores were low in both treatment groups . Clinicians should choose alternative analgesic approaches in these patients Iliac crest bone graft remains the gold st and ard in achieving spinal arthrodesis , but chronic pain from graft harvest occurs in up to 39 % of patients . Studies have shown that a single administration of local anesthetic reduces short-term pain , but they have not adequately investigated possible longer-term benefits . The goal of this study was to determine whether local administration of bupivacaine after iliac crest bone graft harvesting reduces pain and improves patient-reported outcomes . In this prospect i ve , r and omized , controlled , and blinded clinical study , 40 patients were identified who underwent posterior spine fusion with iliac crest bone graft and were r and omized to receive either bupivacaine ( treatment group , n=20 ) or saline ( control group , n=20 ) at the iliac crest bone graft site . Pain at the harvest site was determined by a series of 12 visual and numeric pain scale assessment s. Short Form-12 mental and physical component scores , EuroQol-5D , and Oswestry Disability Index assessment s were made , along with determination of patient satisfaction and self-reported outcome of surgery . Baseline pain and outcome assessment s were statistically similar ( P>.05 ) . Average pain scores were lower for all 12 assessment s in the treatment group at mean follow-up of 5 weeks ( significant differences in 6 assessment s ) and 20 weeks ( significant differences in 2 assessment s ) . No significant differences were found in Short Form-12 and EuroQol-5D scores . For patients who underwent lumbar fusion , the treatment group had significantly improved Oswestry Disability Index scores ( mean±SD=10.8±7.1 vs 18.7±5.9 , P=.012 ) . Significantly more patients in the treatment group reported that surgery met all expectations ( 90 % vs 50 % , P=.016 ) . This study is the 1st to show that a single administration of bupivacaine at the iliac crest bone graft harvest site during posterior spine fusion surgery can result in improved outcomes and reduced pain far beyond the anesthetic duration of activity Summary Background . A r and omized prospect i ve double-blinded study was conducted in 100 patients suffering from mono- or bisegmental cervical retrospondylosis or disc herniation . Method . In group I , 50 patients were treated by injection of 10 ml Ropivacaine 7,5 % at the iliac crest bonegraft donorsite . Local anaesthetic ( LA ) was injected through the wound drainage after closure of the muscle fascia , the suction drainage was opened after closure of the skin . Group II was treated with 0,9 % saline . Operator and patient were blinded to the injected substance . Daily controls of pain intensity were made with the 10 cm visual analog scale from 0 ( no pain ) to 10 ( severe pain ) for 5 days . All patients were question ed regarding pain character and movement provoking pain . Additional pain medication was st and arized . Findings . Statistical analysis of mean pain intensity over the whole hospital stay showed a significant difference in pain intensity between the two groups ( p = 0,017 , Chi-Square test ) . The comparison between pain intensity with LA and without LA showed a gradual increase in statistical significance from day 1 to day 5 ( day 1 : p = 0,54 , not significant ; day 2 : p = 0,026 ; day 3 : p = 0,008 ; day 4 : p = 0,004 ; day 5 : p = 0,002).Interpretation . This data shows that intra-operative blockage of peripheral nociceptive structures results in decreased pain at later time points . We conclude that wound infiltration with 7,5 % Ropivacaine after bonegraft removal at the iliac crest is effective in reducing postoperative pain Surgical field infiltration with adrenaline is common practice for quality surgical field during cleft lip and palate repair in children . Intravascular absorption of adrenaline infiltration often leads to adverse haemodynamic responses . In this prospect i ve , double-blinded , r and omised study the haemodynamic effects , quality of surgical field and postoperative analgesia following surgical field infiltration with different concentrations of adrenaline with and without lignocaine were compared in 100 American Society of Anesthesiologists physical status I children aged six months to seven years undergoing cleft lip/palate surgery . A st and ard anaesthesia protocol was used and they were r and omised into four groups based on solution for infiltration : adrenaline 1:400000 ( group A ) , adrenaline 1:200,000 ( group B ) , lignocaine + adrenaline 1:400,000 ( group C ) and lignocaine + adrenaline 1:200,000 ( group D ) . Statistically significant tachycardia and hypertension occurred only in group B as compared to other groups ( P < 0.001 ) . The peak changes in heart rate and mean arterial pressure following infiltration occurred at 4.3±2.4 , 3.8±1.5 , 5.7±3.2 and 5.9±4.9 minutes in groups A , B , C and D respectively . Surgical field was comparable among all groups . Postoperative pain scores and rescue analgesic requirements were lesser in the groups where lignocaine was added to the infiltrating solution ( P < 0.05 ) . We found that 1:400000 or 1:200000 adrenaline with lignocaine 0.5 to 0.7 % is most suitable for infiltration in terms of stable haemodynamics , quality of surgical field and good postoperative analgesia in children Background : Postoperative pain mostly results from sensitization of afferent fibers at injury sites driving central sensitization . Recently , peripheral processes have gained attention as mechanisms of hyperalgesia , and prostagl and ins are among highly sensitizing agents . To date , perioperative administration of a single local dose of nonsteroidal antiinflammatory drugs has shown inconclusive efficacy . Rather than a single bolus , the current study evaluates the postoperative analgesic effect of diclofenac continuous intrawound infusion after elective cesarean delivery . Methods : Ninety-two parturients were r and omly allocated to receive a 48-h continuous intrawound infusion with 240 ml containing 300 mg diclofenac , 0.2 % ropivacaine , or saline . In the ropivacaine and sal 
    Output:
    
We conclude that there is moderate- quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section .
There is low- quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery .
On a caution ary note , we can not extend our conclusions to other surgical interventions or regional anaesthesia techniques , for example we can not conclude that paravertebral block reduces the risk of PPP after thoracotomy .