title: Combination of nerve blockade and intravenous alfentanil is better than single treatment in relieving postoperative pain.
abstract: OBJECTIVE
  Multimodal analgesia can improve perioperative analgesia but knowledge of combination protocols is still incomplete. This study was designed to evaluate whether the combination of sciatic nerve blockade (SNB) and intravenous alfentanil (IVA) is more effective than either single treatment in relieving postoperative pain in rats.
  
  
  METHODS
  In a plantar incision model, withdrawal thresholds were evaluated by von Frey test before incision as baselines and for 7 days after incision. The animals were randomly allocated into various groups to receive SNB with 1% or 2% lidocaine, IVA of 50 or 150 μg/kg, or combined treatments (SNB 1% + 50 μg/kg IVA or SNB 2% + 150 μg/kg IVA) before incision. The results were compared with those of sham procedures--i.e., injections of peri-sciatic or intravenous saline, or a combination of both.
  
  
  RESULTS
  Plantar incision caused postoperative allodynia for 3 days. SNB with 2% lidocaine reduced allodynia at 1 hour, 3 hours, day 1, and day 2, but not at postoperative 5 hours or days 3-7, whereas 150 μg/kg IVA produced short analgesia for only 3 hours after surgery. Neither low-dose SNB nor low-dose IVA had a significant effect. When high-dose SNB and high-dose IVA were combined, a strong antiallodynic effect was shown in an additive manner. No synergism was evidently displayed by the combination.
  
  
  CONCLUSIONS
  Our results indicated that in an incisional pain model, multimodal analgesia is superior to single or no pretreatment; however, the combination of multimodal analgesic treatments should be individually discerned depending on nociceptive types and analgesic mechanisms.
authors.affiliation: School of Medicine, China Medical University, Taichung,Taiwan.
authors.forename: Yeong-Ray
authors.initials: YR
authors.lastname: Wen
authors.forename: Chih-Peng
authors.initials: CP
authors.lastname: Lin
authors.forename: Ming-Dar
authors.initials: MD
authors.lastname: Tsai
authors.forename: Jui-Yuan
authors.initials: JY
authors.lastname: Chen
authors.forename: Chih-Chun
authors.initials: CC
authors.lastname: Ma
authors.forename: Wei-Zen
authors.initials: WZ
authors.lastname: Sun
authors.forename: Chia-Chuan
authors.initials: CC
authors.lastname: Wang
mesh_terms: D015760:Alfentanil; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D000818:Animals; D004305:Dose-Response Relationship, Drug; D008012:Lidocaine; D008297:Male; D009407:Nerve Block; D010149:Postoperative Pain / Q000517:prevention & control*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve; D016896:Treatment Outcome
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D015760:Alfentanil; D008012:Lidocaine