***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 : Pain following spinal cord injury ( SCI ) is a therapeutic challenge . Only a few treatments have been assessed in r and omized , controlled trials . The primary objective of the present study was to examine the analgesic effect of ketamine and lidocaine in a group of patients with neuropathic pain below the level of spinal cord injury . We also wanted to assess sensory abnormalities to see if this could help us to identify responders and if treatments result ed in changes of sensibility Background Several lines of evidence suggest that neuropathic pain ( including Complex Regional Pain Syndrome [ CRPS ] I and CRPS II ) is mediated in part by an increase in the density of voltage-sensitive sodium channels in injured axons and the dorsal root ganglion of injured axons . This study sought to characterize the effects of intravenous lidocaine ( a sodium channel blocker ) on acute sensory thresholds within the painful area and the size of the painful area in patients suffering from CRPS I and II . Methods This study used a r and omized , double-blind , placebo-controlled design in 16 subjects suffering from CRPS I and II with a prominent allodynia . Each subject received an intravenous infusion of lidocaine and diphenhydramine separated by 1 week . A computer-controlled infusion pump targeted stair-step increases in plasma levels of lidocaine of 1 , 2 , and 3 & mgr;g/ml . At baseline and at each plasma level , spontaneous and evoked pain scores and neurosensory testing within the painful area were measured . The neurosensory testing consisted of thermal thresholds , tactile thresholds and the area of allodynia to punctate , and stroking and thermal stimuli . Results Intravenous lidocaine and diphenhydramine had no significant effect on the cool , warm , or cold pain thresholds . However , lidocaine caused a significant elevation of the hot pain thresholds in the painful area . Intravenous lidocaine caused a significantly decreased response to stroking and cool stimuli in the allodynic area . There was also a significant decrease in pain scores to cool stimuli at all plasma levels and the spontaneous pain at the highest plasma level . Conclusions This study demonstrates that intravenous lidocaine affects pain in response to cool stimuli more than mechanical pain in subjects with neuropathic pain . There is a lesser effect on spontaneous pain and pain induced by stroking stimuli and no effect on the pain induced by punctate stimuli Background : The mechanisms underlying neuropathic pain are incompletely understood . Targeting specific molecular mechanisms in the pain signaling system may assist in underst and ing key features in neuropathic pains such as allodynia . This study examined the effect of systemically administered ketamine , an N-methyl-d-aspartate receptor antagonist and lidocaine , a sodium channel blocker , on spontaneous pain , brush-evoked pain , and pinprick-evoked pain in patients with nerve injury pain . Methods : Twenty patients participated in two r and omized , double-blinded , placebo-controlled , crossover experiments in which they , on four different days , received a 30-minute intravenous infusion of ketamine ( 0.24 mg/kg ) , lidocaine ( 5 mg/kg ) , or saline .  Ongoing pain , pain evoked by brush and repetitive pinprick stimuli , and acetone was measured before , during , and after infusion . Results : Ketamine significantly reduced ongoing pain and evoked pain to brush and pinprick , whereas lidocaine only reduced evoked pain to repetitive pinprick stimuli . In individual patients , there was no correlation between the pain-relieving effect of lidocaine and ketamine on ongoing or mechanically evoked pains . Conclusions : N-methyl-d-aspartate receptor-linked systems and sodium channels are involved in generation and maintenance of pain in patients with peripheral nerve injury . It is likely that ongoing pain as well as mechanical hyperalgesia in individual patients is dependent on several separate molecular mechanisms & NA ; In a double‐blind controlled design , 7 patients with painful diabetic neuropathy received lidocaine 5 mg/kg or saline intravenously over a period of 30 min . Thermal sensibility quantified by thermotest was not affected by lidocaine . In 3 of the patients nociceptive flexion reflex thresholds could be determined . The threshold was increased by lidocaine and returned to pre‐infusion level within 10 days . Lidocaine also increased the threshold in 4 healthy subjects , but did not affect the Hoffmann reflex . These results suggest that lidocaine exerts its pain‐relieving effect on the spinal level in diabetic neuropathy Background : Neuropathic pain in spinal cord injury is a common challenging therapeutic condition . The current study examines the analgesic effect of the sodium channel blocker lidocaine on neuropathic pain in patients with spinal cord injury and the predictive role of concomitant evoked pain on pain relief with lidocaine . Methods : Twenty-four spinal cord injury patients with neuropathic pain at or below the level of injury were r and omized and completed a double-blind crossover trial of 5 mg/kg lidocaine and placebo infused over 30 min . Twelve patients reported evoked pain , and 12 patients had no evoked pain . Spontaneous and evoked pains were assessed using a visual analog scale and quantitative sensory testing . Results : Lidocaine significantly reduced spontaneous pain in all patients ( P < 0.01 ) and in each of the two groups with ( P < 0.01 ) and without ( P = 0.048 ) evoked pain , with no difference in number of responders ( pain reduction ≥ 33 % ) between the patients with ( n = 6 ) and without ( n = 5 ) evoked pain . Lidocaine significantly relieved both at-level and below-level neuropathic pain and decreased brush-evoked dysesthesia but not cold allodynia , pinprick hyperalgesia , or pain evoked by repetitive pinprick . Conclusions : Lidocaine reduced neuropathic pain at and below the level of injury irrespective of the presence or absence of evoked pain . Results are consistent with a central -acting effect of sodium channel blockers acting on neuronal hyperexcitability . Agents ( such as anticonvulsants or antiarrhythmics ) with sodium channel – blocking properties may be a treatment option for spinal cord injury pain Background An intravenous infusion of lidocaine has been used on numerous occasions to produce analgesia in neuropathic pain . In the cases of failed back surgery syndrom , the pain generated as result of abnormal impulse from the dorsal root ganglion and spinal cord , for instance as a result of nerve injury may be particularly sensitive to lidocaine . The aim of the present study was to identify the effects of IV lidocaine on neuropathic pain items of FBSS . Methods The study was a r and omized , prospect i ve , double-blinded , crossover study involving eighteen patients with failed back surgery syndrome . The treatments were : 0.9 % normal saline , lidocaine 1 mg/kg in 500 ml normal saline , and lidocaine 5 mg/kg in 500 ml normal saline over 60 minutes . The patients underwent infusions on three different appointments , at least two weeks apart . Thus all patients received all 3 treatments . Pain measurement was taken by visual analogue scale ( VAS ) , and neuropathic pain question naire . Results Both lidocaine ( 1 mg/kg , 5 mg/kg ) and placebo significantly reduced the intense , sharp , hot , dull , cold , sensitivity , itchy , unpleasant , deep and superficial of pain . The amount of change was not significantly different among either of the lidocaine and placebo , or among the lidocaine treatments themselves , for any of the pain responses , except sharp , dull , cold , unpleasant , and deep pain . And VAS was decreased during infusion in all 3 group and there were no difference among groups . Conclusions This study shows that 1 mg/kg , or 5 mg/kg of IV lidocaine , and palcebo was effective in patients with neuropathic pain attributable to FBSS , but effect of licoaine did not differ from placebo saline & NA ; Ten patients with organic nerve injury causing chronic neuropathic pain were tested for the effects of intravenous lidocaine versus saline upon psychophysical somatosensory variables . The variables assessed were the subjective magnitude of pain , area of mechanical hyperalgesia and presence and magnitude of thermal heat/cold hyperalgesia . The study methods applied to evaluate these conditions were the conventional testing of somatosensory submodalities with area mapping and the subjective magnitude estimation of spontaneous pain . It was found that spontaneous pain and mechanical hyperalgesia were consistently improved , transiently , by intravenous administration of lidocaine in all 10 patients ; areas of hyperalgesia which extended beyond the territory of the nerve also improved transiently . Spontaneous pain and mechanical hyperalgesia , but not hypoesthesia , were transiently improved by injection of saline in only 1 of the 10 patients . This outcome is probably due to a placebo effect . This improvement is in keeping with the inhibition of anomalous neural impulses which can be generated anywhere along the sensory channels responsible for generating spontaneous pain and hyperalgesia . Thus , intravenous lidocaine is proposed as a diagnostic aid in the examination of patients complaining of complex sensory disorders associated with nerve injury . The transient pain relief may allow a fuller identification of the area of sensory loss BACKGROUND Herpes zoster ( HZ ) is associated with inflammation of the peripheral nerves , which is considered to be an important cause of postherpetic neuralgia ( PHN ) . Interventions aim ed at reducing this inflammation could prevent PHN . One option is the epidural administration of corticosteroid and local anesthetic . However , several authors have reported a risk of arachnoiditis with epidural corticosteroids . Subcutaneous injection in an outpatient setting is a safer option . However , there is limited evidence of the effectiveness of this alternative for preventing PHN . OBJECTIVES The aim of this study was to assess the effectiveness of subcutaneous injection of triamcinolone and lidocaine for the prevention of PHN in elderly HZ patients . STUDY DESIGN R and omized , single-center , clinical trial . SETTING Department of pain management of a teaching hospital in Beijing , China . METHODS Patients with acute HZ with rash < 7 days ( n = 100 ) were r and omly assigned to receive either st and ard therapy ( oral antivirals and analgesics ) alone or st and ard therapy plus subcutaneous injection of triamcinolone and lidocaine . The severity of pain was assessed using a numeric rating scale ( NRS ) at enrollment and at one , 3 , and 6 months after rash onset . Quality of life ( QoL ) was evaluated by the SF-36 before treatment and at 3 and 6 months after rash onset . The primary endpoint was the presence of zoster-associated pain ( ZAP ) at 3 months after rash onset . RESULTS At enrollment , all patients reported ZAP with average NRS scores of 6.64 ± 1.44 and 7.16 ± 1.22 in the st and ard group and subcutaneous group , respectively . At 3 and 6 months after rash onset , the pain had decreased in both groups , but the decrease was significantly greater in the subcutaneous injection group . At 3 months , 2 ( 4 % ) patients in the subcutaneous injection group vs. 10 ( 20 % ) patients in the st and ard group had ZAP with NRS > 3 ( P = 0.014 ) . Both groups showed significant improvement in QoL at 3 and 6 months . No patient had major adverse events related to the subcutaneous injection . LIMITATIONS The main limitation of the study was the absence of a placebo subcutaneous injection in the st and ard group . CONCLUSION Subcutaneous injection of triamcinolone and lidocaine in the acute phase of HZ can reduce ZAP more effectively than oral antivirals and analgesics alone , and may be a feasible method to prevent PHN . KEY WORDS Subcutaneous injection , lidocaine , triamcinolone , postherpetic neuralgia , prevention Objectives : This study evaluated the analgesic efficacy and emotional response to intravenous lidocaine infusion compared with placebo in patients with postherpetic neuralgia ( PHN ) . Methods : In this r and omized , double-blinded study , patients with PHN received 5 mg/kg intravenous lidocaine infusion or placebo . The primary outcome was pain measured by Visual Analogue Scale , Von Frey , and area of allodynia . Moreover , emotional status of anxiety and depression were evaluated by Self-rating Anxiety Scale ( SAS ) and Self-rating Depression Scale ( SDS ) . Quality of life was assessed by Short Form Health Survey 36 . Results : In total , 197 patients were enrolled and eligible data were collected from 183 of those patients . The Visual Analogue Scale scores were reduced to a minimum at 2 weeks ( 2.74 , 2.99 ) after infusion , but no significant difference was found between the lidocaine and placebo groups . Similar changes were also found in mechanical pain threshold and area of allodynia . However , the lidocaine group was associated with a statistically significant reduction in consumption of analgesics with a relative risk of 6.2 ( 95 % confidence interval [ CI ] , 2.24 - 17.16 ) . Lidocaine infusion also significantly improved the anxiety and depression status ; the values of mean change in anxiety and depression were 3.89 ( 95 % CI , 1.43 - 6.35 ) and 4.3 ( 95 % CI , 0.63 - 7.98 ) , respectively , at 2 weeks . Moreover , improvement was exhibited in Short 
    Output:
    
Conclusion : Our study indicates that while IV lidocaine is effective in pain control among patients with neuropathic pain in the immediate post-infusion period , it does not have a long-lasting , persistent effect .
IV infusions of the drug are associated with an increased risk of side effects compared to a placebo .
However , the risk of serious adverse events is negligible .