The Pharmacokinetics and Efficacy of Ropivacaine Continuous Wound Instillation After Spine Fusion Surgery Margherita Bianconi, MD*, Luca Ferraro, PharmD†, Riccardo Ricci, MD*, Gustavo Zanoli, MD‡, Tiziana Antonelli, MD†§, Bighetti Giulia, MD‡, Aurelia Guberti, MD*, and Leo Massari, MD‡ Departments of *Anesthesiology and Intensive Care and §Clinical Pharmacology, St. Anna Hospital, Ferrara, Italy; and Departments of †Clinical and Experimental Medicine, Section of Pharmacology, and ‡Biomedical Sciences and Advanced Therapies, Section of Orthopaedics and Traumatology, University of Ferrara, Ferrara, Italy Because local anesthetic continuous wound instillation has not been evaluated after spine fusion surgery, we designed this study to determine whether this tech- nique could enhance analgesia and improve patient outcome after posterior lumbar arthrodesis. Thirty- eight patients undergoing spine stabilization were ran- domly divided into two groups. The M group received a postoperative baseline IV infusion of morphine plus ketorolac for 24 h, and the R group received IV saline. In both groups, a multihole 16-gauge catheter was placed subcutaneously; in the R group, the wound was infil- trated with a solution of ropivacaine 0.5% 200 mg/ 40 mL, and infusion of ropivacaine 0.2% 5 mL/h was maintained for 55 h. In the M group, saline infusion was given at the same rate. Pain scores were taken at rest and on passive mobilization by nurses blinded to pa- tient analgesic treatment. The total plasma ropivacaine concentration was evaluated. Pain scores and rescue medication requirements (diclofenac and tramadol) were significantly less in the R group than in the M group. Postoperative blood loss was less and the length of hospital stay was shorter in the R group. The ropiva- caine peak total plasma concentration occurred at 24 h during infusion and was within safe limits; no toxic lo- cal anesthetic side effects were observed. These results suggest that wound infiltration and continuous instilla- tion of ropivacaine 0.2% is effective for pain manage- ment after spine stabilization surgery. (Anesth Analg 2004;98:166 –72) P ostoperative pain after posterior lumbar stabili- zation surgery is related to soft tissue and mus- cle dissection and to manipulations and removal at the operation site. Most patients complain of severe pain at rest during the first 12 h after surgery. This pain increases considerably with mobilization because of the reflex spasm of paraspinal muscles that is trig- gered by the primary wound pain (1). During the following 48 –72 h, postoperative back pain is gener- ally moderate at rest, whereas it remains severe on movement and produces discomfort that can interfere with patient mobilization and, possibly, with dis- charge time. Reuben et al. (2) found that continuous systemic administration of nonsteroidal antiinflamma- tory drugs (NSAIDs) is effective in controlling pain after lumbar stabilization surgery. Moreover, when associated with centrally acting drugs such as opioids, NSAIDs have an opioid-sparing effect (3,4). Despite the favorable effects of analgesia in the early postoperative period, this drug association may pro- duce a number of well-known side effects, such as nausea, vomiting, respiratory depression, sedation, re- nal abnormality, and upper gastrointestinal and oper- ative site bleeding (5). Finally, NSAID administration might have an inhibitory effect on the spinal fusion rate (6,7). Local anesthetic infiltration of the surgical wound is a useful method in the treatment of postop- erative pain after various surgical procedures (8 –12), but, at present, there is no clinical evidence of real effectiveness and safety of continuous wound perfu- sion after spinal surgery. The major limitations of currently available local anesthetics are the relatively short duration of action and the potential risk of systemic toxicity. Further- more, studies performed so far have not provided definitive data concerning either the evaluation of the optimal method and time for infiltration or the opti- mal dosage/volume of local anesthetic, particularly regarding its systemic absorption and toxicity (13), which may increase during the large surgical incisions Supported by AstraZeneca SpA, Basiglio, Milano, Italy. Accepted for publication August 13, 2003. Address correspondence and reprint requests to Tiziana An- tonelli, MD, Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44100, Ferrara, Italy. Address e-mail to ant@unife.it. DOI: 10.1213/01.ANE.0000093310.47375.44 ©2003 by the International Anesthesia Research Society 166 Anesth Analg 2004;98:166–72 0003-2999/03