this indicates that back pain may be associated with local trauma and nerve injury caused by the epidural needle , leading to aseptic periosteitis , tendonitis , ligamentous inflammation and/or osteochondritis , which result in lumbar pain . in 2009 .   found that local administration of nonsteroidal anti - inflammatory drugs significantly relieved post - epidural low back pain . because of its anti - inflammatory effects , dexamethasone has been used to treat post - epidural lumbar pain and to reduce the consumption of postoperative analgesics . some studies have shown that epidural injection of dexamethasone could reduce back pain [ 79 ] . therefore , we hypothesized that prophylactic dexamethasone infiltration along the needle insertion pathway can decrease the incidence of lumbar pain after spinal - epidural anesthesia . the aim of this prospective , double - blinded , randomized study was to evaluate the effect of local dexamethasone infiltration on incidence and severity of lumbar pain during the first 3 days and 6 months postoperatively . the study protocol and informed consent form were reviewed and approved by the ethics committee of the second affiliated hospital of harbin medical university . from march 17 , 2011 to may 17 , 2012 , 160 consecutive patients , asa i  ii , aged 2060 years and scheduled for abdominal gynecologic surgery were randomly allocated by random number table , into a lidocaine group ( l ) and a local dexamethasone plus lidocaine group ( dl ) . patients were excluded if they had a history of chronic lumbar pain , a history of lumbar injury or surgery , analgesic or anticoagulant usages within the 2 weeks before surgery , hypersensitivity to nsaids or local anesthetics , or a history of systemic disorders such as diabetes mellitus or a disease affecting the liver , heart , or kidney . moreover , patients with history of drug or alcohol abuse , psychiatric disorders , or surgical complications were excluded . patients in whom spinal - epidural needle was inserted at a different space were excluded . three anesthesiologists participated in this study . only the first anesthesiologist who prepared the local infiltration drugs for the second anesthesiologist administered anesthesia to all patients , and the third anesthesiologist observed and assessed patients conditions in wards post - operatively and by telephone after discharge from hospital . the patients in group l received 4 ml of 1% lidocaine for local infiltration , and patients in group dl received 4 ml of a mixture containing 1% lidocaine and 5 mg of dexamethasone . local infiltrations with a 27-gauge ( 3 cm ) needle of the skin , subcutaneous tissue , interspinal ligaments , and muscle with either 1% lidocaine alone or with dexamethasone added was performed . the anesthesiologist introduced the epidural needle ( 17-gauge ) at the l2 - 3 or l3 - 4 interspace via the midline approach . after identification of the epidural space by loss of resistance to air , the spinal needle ( 25-gauge ) was inserted to puncture the dura , and 15 mg of 0.5% bupivacaine were injected when free flow of cerebrospinal fluid was observed . after injection of bupivacaine , 5 cm of the epidural catheter was inserted into the epidural space . if the bp and hr were 30% below their baseline values , ephedrine and atropine were administered intravenously . in case of failure of spinal - epidural anesthesia after the operation , epidural morphine 20 gkg was given for postoperative analgesia , and then the epidural catheter was removed . in the ward , patients were placed in a supine position without a pillow to prevent postoperative headaches . when patients complained of wound pain and the visual analog scale ( vas ) was greater than 4 , 1 g / kg fentanyl intravenously was given . the third anesthetist assessed acute back pain in the ward on the 1 , 2 and 3 day ( d1 , d2 and d3 timepoints , respectively ) . during assessment , the patients were placed in the knee - chest position and asked whether they felt back pain . the score of pain was assessed by a 10-point vas , where 0 equals to  no pain  and 10 equals to  the worst pain  . if vas score was greater than 4 , 1 g / kg of intravenous fentanyl was prescribed for the patient . however , when the patients reported that they were suffered back pain at anytime during postoperative 3 days , even though not at the assessment time point ( 24 , 48 and 72 hour ) , the third anesthetist would assess the back pain and inject the fentanyl ( 1 gkg ) . when this happened at the time of back pain evaluation , assessment of lumbago was delayed for 2 hours following fentanyl injection . total consumption of fentanyl in each patient within 72 hours postoperatively was recorded . in the postoperative 1 , 2 and 6 month , the third anesthesiologist assessed the back pain of patients by telephone with the same method during 3 postoperative days ( asking the following questions : 1 . have you suffered from any other discomforts such as localized or lower limb paresthesias and unilateral or bilateral sciatic leg pain ? ) . any analgesic used for back pain after discharge from hospital the incidence and score of lumbar pain were assessed with the same ways used in ward . during the first month , the patients were forbidden to engage in heavy exercise and labor to avoid aggravating back pain . patients were divided into 2 categories ; chronic back pain accompanied with and without acute back pain . headaches , lower limb paresthesia , and unilateral or bilateral sciatic leg pain were recorded in wards during the first 3 postoperative days . puncture site infection was monitored at the 1 , 2 , and 6 months in the hospital . sample size was based on previous studies that indicate that the incidence of lumbar pain on the first day after epidural anesthesia in non - obstetric patients was approximately 20% . to achieve a statistical power of more than 80% , with a significance criteria (  ) of 0.05 , seventy - one patients were needed in each group to detect a difference of 15% in the incidence of back pain between the two groups ( pass , 2008 , 2008 , kaysville , utah ) all the data were analyzed using the spss 13.0 ( ibm , armonk , ny , usa ) . normally distributed data including age , weight , height , operation time , anesthesia puncture time were presented as the mean ( sd ) and analyzed using unpaired t - test . the non - normally distributed data ( number of punctures ) was analyzed by kruskal - wallis h test . the incidence ( percentage ) and severity of back pain ( vas score ) were analyzed using the kruskal - wallis h test and the p value was calibrated with the benjamini & hochberg method . sample size was based on previous studies that indicate that the incidence of lumbar pain on the first day after epidural anesthesia in non - obstetric patients was approximately 20% . to achieve a statistical power of more than 80% , with a significance criteria (  ) of 0.05 , seventy - one patients were needed in each group to detect a difference of 15% in the incidence of back pain between the two groups ( pass , 2008 , 2008 , kaysville , utah ) all the data were analyzed using the spss 13.0 ( ibm , armonk , ny , usa ) . normally distributed data including age , weight , height , operation time , anesthesia puncture time were presented as the mean ( sd ) and analyzed using unpaired t - test . the non - normally distributed data ( number of punctures ) was analyzed by kruskal - wallis h test . the incidence ( percentage ) and severity of back pain ( vas score ) were analyzed using the kruskal - wallis h test and the p value was calibrated with the benjamini & hochberg method . the demographic data , data of anesthesia puncture and surgeries , fentanyl requirements for wound pain and dosage of epidural bupivacaine are shown in table 1 . the incidence and severity of acute and chronic back pain in both study groups is shown in figures 2 and 3.the incidence of pain was significantly lower in the dl group at all observation timepoints . table 2 shows the incidence of chronic back pain in patients without acute back pain between groups , which was significantly lower in the dl group at all observation timepoints . regarding pain severity , at d1 and d2 timepoints , the vas scores were significantly lower in group dl . at d3 , the vas score in group dl was lower than in group l , but the difference was not significant . at m1 and m2 timepoints , the vas scores were significantly lower in group dl but there was no significant difference at m6 . during the first post - operative day , there were 11 patients in group l and 4 patients in group dl who requested fentanyl for lumbar pain . in the second post - operative day , there were 4 patients in group l who requested fentanyl for lumbar pain . in this study , the third anesthetist injected fentanyl for back pain in the 2 groups at any time when vas score was over 4 , not only at the postoperative 24 , 48 , or 72 hour timepoint . therefore , the vas score was lower than 4 when we assessed the patients at postoperative hours24 , 48 , or 72 hour . the total consumption of fentanyl was significantly lower in group dl than group l during the postoperative 3 days ( figure 4 ) . eleven patients ( 5 patients in group l and 6 patients in group dl ) reported lower limb paresthesia , and 5 patients ( 2 patients in group l and 3 patients in group dl ) reported unilateral sciatic leg pain during the first 3 post - operative days . in post - operative months 16 , there were 5 patients ( 2 patients in group l and 3 patients in group dl ) who reported lower limb paresthesia and 2 patients ( 2 patients in group dl ) with unilateral paresthesia in the 2 groups . there were no significant differences in the incidence of adverse events between the 2 groups . secondary outcomes were lumbar pain as measured by the vas score and analgesic consumption for back pain . this study demonstrated that prophylactic local dexamethasone could decrease the incidence of acute and chronic back pain , and also lower vas for back pain following combined spinal - epidural anesthesia . we also found that dexamethasone for local infiltration can decrease the incidence of chronic back pain in patients without acute back pain . spinal - epidural anesthesia is commonly used in gynecological surgery , but low back pain after epidural anesthesia is a common and significant problem . low back pain is multifactorial and is associated with local trauma caused by the epidural needle , the body mass index , surgical position and time , and number of epidural attempts . local tissue trauma causes local pain , tissue edema , and the release of pro - inflammatory factors , chemokines , substance p , and vasoactive intestinal peptide . additionally , acute nociception of puncture site leads to release of tnf- , il-1 and il-8 , which in turn contributes to the release of peripheral hyperalgesic mediators . for example , induction of cyclo - oxygenase-2 and activation of phospholipase a2 leads to intraspinal prostaglandin synthesis , which results in a peripheral and central hyperalgesic state . muslu et al .   in 2009 and wang et al .   in 1998 found that local administration of nonsteroidal anti - inflammatory drug with lidocaine could reduce the incidence and severity of post - epidural backache better than lidocaine alone . muslu et al .   in 2009 locally administered lornoxicam to lessen the incidence of back pain , but the authors could not evaluate its effect on chronic back pain because the half - life of lornoxicam is less than 4 hours . a local dexamethasone infiltration can inhibit the inflammation of local trauma and the release of inflammatory factors for over 36 hours . therefore , dexamethasone can significantly decrease the incidence of acute back pain in the first 3 postoperative days . the analgesic effect of dexamethasone for local infiltration may be associated with the direct inhibition of local inflammation . inflammation plays a key role in pain , and many studies have reported that inflammatory cytokines may be involved in pain processes [ 1921 ] . dexamethasone , a well - known anti - inflammatory drug , is widely used to treat inflammation . additionally , dexamethasone can inhibit phospholipase a2 and the expression of cyclo - oxygenase-2 during inflammation , reducing the synthesis of prostaglandins , which play a major role in pain . we investigate the effect of dexamethasone on acute and chronic back pain and found that dexamethasone reduced the incidence of both acute and chronic back pain . this effect may be associated with anti - inflammation and inhibition of peripheral hyperalgesic state . inflammatory mediators can modulate nociception and contribute to the amplification and persistence of pain [ 21,2427 ] . local dexamethasone infiltration can inhibit the peripheral hyperalgesic state via inhibition of pro - inflammatory factors and cytokines . interestingly , we found dexamethasone significantly decreased the incidence of chronic back pain in patients without acute back pain . we could not understand the mechanism of how these patients without preoperative back pain and acute back pain experienced chronic back pain after combined spinal - epidural anesthesia . these patients might have had local trauma caused by the epidural needle , needed to resume work or other physical labor resulting in chronic back pain , or due to dexamethasone s effects of anti - inflammation and inhibition of phospholipase a2 and cyclo - oxygenase-2 to reduce the incidence of chronic back pain in patients without acute back pain . in this study , the incidence of lumbar pain was significantly higher than that reported by hakim et al . in 2012 , this may be due to differences in methods of pain assessment , in our study , the pain was evaluated in knee - chest position , which was not used in study of hakim . in this study , we did not compare the effect of different methods of administration of dexamethasone , including intravenous injection and epidural injection . further research is needed to compare the effect of different administration methods of dexamethasone on postoperative lumbar pain . in the future , we also will focus on the mechanism in patients suffering chronic back pain without acute back pain . in addition , this method is suitable for laparotomy but not minimally invasive surgery such as laparoscopic surgery and robotic surgery , which are currently widely used in gynecological surgery . in this study , we did not compare the effect of different methods of administration of dexamethasone , including intravenous injection and epidural injection . further research is needed to compare the effect of different administration methods of dexamethasone on postoperative lumbar pain . in the future , we also will focus on the mechanism in patients suffering chronic back pain without acute back pain . in addition , this method is suitable for laparotomy but not minimally invasive surgery such as laparoscopic surgery and robotic surgery , which are currently widely used in gynecological surgery . the addition of dexamethasone to local lidocaine infiltration decreases the incidence and vas score of lumbar pain after gynecological non - laparoscopic surgery . it also reduces the dosage of supplementary analgesics required after combined spinal - epidural anesthesia .
backgroundthe aim of this study was to evaluate the effect of dexamethasone added to local lidocaine infiltration on incidence and severity of backache after combined spinal - epidural anesthesia for gynecological surgery.material/methodswe randomly allocated 160 patients to receive either local lidocaine infiltration along the pathway of the spinal - epidural needle ( group l ) or local dexamethasone and lidocaine infiltration ( group dl ) . 
 the incidence and scores for back pain were evaluated on the first , second , and third day ( acute lumbago ) and first , second , and sixth month ( chronic lumbago ) after surgery . 
 fentanyl consumption for management of back pain was recorded.resultsthe incidence of acute , subacute , and chronic back pain was significantly lower in the dl group than the l group ( p<0.05 for all comparisons ) . 
 the vas score for back pain on the first and second day and first and second month , were significantly lower in the dl group than the l group ( p=0.0028 , p=0.017 ; p<0.001 , both ) , but there were no significant differences on the third day and sixth month . 
 fentanyl consumption in the first 3 postoperative days was significantly lower in the dl group than in the l group ( p<0.001 ) . 
 the incidence of back pain during the first , second , and sixth month in patients who did not have preoperative lumbago were significantly lower in the dl group than in the l group ( p<0.001 , both).conclusionsaddition of dexamethasone to local lidocaine infiltration effectively decreases the incidence and severity of back pain after combined spinal - epidural anesthesia implemented for gynecological surgery .