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Weekly UpdatesAbstract: Autogenous iliac crest bone grafts are often used for persons undergoing anterior cervical fusion (ACF). Study findings have shown that pain at the iliac crest donor site can often be more severe than that at the primary operation site. A method used to eliminate pain after bone harvesting involves infiltration of a local anesthetic directly into the site. This study examined the efficacy of local anesthetic infiltration in the control of donor site pain, utilizing a randomized, double-blind, placebo-controlled design. All participants received standard postoperative intravenous and oral analgesic. Those in the study group also received six injections of bupivacaine hydrochloride 0.25% into the donor site, while participants in the placebo group received normal saline injections. Participants receiving bupivacaine (n = 14) consistently reported lower hip pain scores than participants receiving the placebo (n = 8), with significant differences noted 3 hours after the first and second doses of the study drug. The bupivacaine group's mean morphine intake for the first 24 hours after surgery was found to be lower (32 mg; placebo 44 mg), whereas participants younger than 49 years who received bupivacaine were found, on average, to have stayed in the hospital one day less (3.6 days) than placebo group participants (4.5 days). Younger participants receiving bupivacaine required less morphine and had, on average, a reduced length of stay. The clinical implication of using local anesthetic for the relief of donor site pain suggests that it is a safe and efficacious technique.
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Autologous iliac crest bone grafts are often used for persons undergoing anterior cervical fusion (ACF). Pain is generally experienced in the iliac crest following graft procurement. Patients often complain of experiencing more pain in the donor site region than at the recipient site (Brull, Lieponis, Murphy, Garcia, & Silverman, 1992; Chester, Ravindranath, White, Shanahan, & Lloyd-Williams, 1989; Goulet, Senunas, DeSilva, & Greenfield, 1997; Kalk, Raghoebar, Jansma, & Boering, 1996). The purpose of this randomized controlled study (RCT) was to determine the efficacy of local anesthetic infiltration in the control of postoperative iliac crest donor site pain.
Background
Procurement of bone from the iliac crest is a common procedure (Robertson & Wray, 2001; Russell & Block, 2000; Seiler & Johnson, 2000). Donor site pain has been reported as the major morbidity of bone harvesting (Goulet et al., 1997; Kalk et al., 1996; Laurie, Kaban, Mulliken, & Murray, 1984; Robertson & Wray, 2001). Todd & Reed (1991) noted that for differing orthopedic procedures, the iliac bone graft site pain was more severe and often worse than the primary operation site. Similar findings were reported for bone harvesting of patients undergoing maxillofacial procedures (Kennedy & Hiranaka, 1995). In addition, during the postoperative phase patients have reported difficulty walking due to donor site pain (Goulet et al., 1997; Kalk et al., 1996). This finding is supported by Summers and Eisenstein (1989), who in a study of 81 patients undergoing lumbar spinal fusions reported that 69% of patients stated that walking aggravated their donor site. A further 87% of the patients were unable to lie on the affected side due to donor site pain.
Although research is available on the complications resulting from bone graft harvesting, there is a paucity of literature on donor site pain management, particularly with regard to ACF procedures. One method used to eliminate pain from the iliac crest following donor bone harvesting involves infiltration of a local anesthetic directly into the site via a catheter (Kennedy & Hiranaka, 1995). The local anesthetic commonly used is bupivacaine hydrochloride, which has a rapid onset; anesthesia occurs within 4-17 minutes of administration. The duration of action ranges from 3 to 7 hours. The elimination of bupivacaine is triphasic, with the mean half life ranging from 1.5 to 5.5 hours in adults (McEvoy, 2000).
Other techniques of delivering the bupivacaine have been investigated, including regular intermittent injections, single infiltration on wound closure, or continuous infusion at wound or donor site via a pump or syringe driver (Brull et al., 1992; Kennedy & Hiranaka, 1995; Wilson, 1995). The infiltration of bupivacaine via a catheter into the surgical wound during the early postoperative period has been proven to be an effective pain relief measure and is a useful adjunct to other common analgesic practices (Laurie et al., 1984; Rickards, 1993; Scott, 1992; Todd & Reed, 1991).
Brull et al. (1992) claimed that patients receiving bupivacaine locally into the iliac crest donor site had a reduction in their postoperative pain, as measured by lower donor site pain scores and the concomitant reduction in morphine usage. Anecdotal evidence cited by Rickards (1993) supports these findings.
Kennedy and Hiranaka (1995) studied 30 patients who received bupivacaine into the iliac crest donor site via a catheter at 8-to 12-hour intervals. The patients' responses to the relief of pain were reported as being very positive, and early ambulation on the first postoperative day occurred in the majority of cases. Kennedy and Hiranaka (1995) and Brull et al. (1992) stated that there were no adverse local anesthetic reactions or wound complications with the infiltration of bupivacaine via a catheter. This finding was reiterated by Kennedy and Hiranaka (1995), who reported that none of the patients experienced infection, hematoma, or seroma associated with the donor site due to catheter insertion. The current literature thus supports the use of intermittent use of bupivacaine as an effective means of providing donor site pain relief.
To date, research focusing on the effectiveness of local analgesic relief specific to the iliac crest donor area for patients undergoing vertebral fusion has consisted of a small number of studies that have utilized historical controls, or retrospective designs or consisted of samples with fewer than 10 patients. For this reason a double-blind RCT design was chosen to evaluate the efficacy of this technique. Because there is a paucity of literature on the effectiveness of this technique in reducing donor site pain, results from this study will add to the body of literature in this area.
Although the primary concern was to provide maximum pain relief for the patient, the economic ramifications of utilizing an effective pain relief technique also were under review. It was proposed that increasing a patient's mobility and independence could reduce their length of stay in hospital and, thus, costs.
Method
Study Design
A randomized, double-blind, placebo-controlled study examining the effect of local anesthetic infiltration versus a saline placebo infiltration for the control of iliac crest donor site pain following a single-level ACF was conducted in the neuroscience surgical unit of a major Australian teaching hospital over an 18-month period.
Sampling
Approval from the Medical and Allied Subcommittee and the Human Research Ethics Committee of the hospital was sought prior to implementation of this study. The participants for this study were obtained utilizing a consecutive sampling process. All English-speaking participants undergoing a single-level ACF with allograft were considered for the study. Time period for data collection was to be 12 months. The data collection period was extended by 6 months because an insufficient number of participants were recruited due to fewer elective ACF operations being performed. Participants who had the procedure as a result of acute trauma or malignancy were excluded. Any patient with a known allergy to local anesthetic also was excluded from the study.
Participants were randomized into a placebo or study group. The placebo group (n = 8) received a saline infiltration for donor site pain as well as the standard intravenous (IV) opioid analgesic (morphine). The study group (n = 14) received local bupivacaine infiltration for donor site pain as well as the standard IV opioid analgesic.
Procedure and Data Collection
A detailed informed consent sheet was given to potential participants at their pre-admission appointment or on the ward the day prior to surgery. After consent was obtained, participants were randomized to the appropriate group.
After the iliac crest graft was harvested, a percutaneous wound drain was placed alongside a percutaneous catheter for infiltration of the study/placebo treatment. Once in the recovery room, the participant was given a low dose (0.25%) of bupivacaine hydrochloride (10 ml) or normal saline (10 ml) as prepared by the pharmacy department. This injection was administered over 5 minutes with the wound drain closed for 15 minutes to facilitate absorption.
In view of bupivacaine's pharmacokinetics, wound infiltration with local anesthetic or normal saline (placebo) occurred routinely every 6 hours for the first 24-48 hours. After 48 hours the iliac crest catheter was then removed. All registered nurses were educated to administer the local anesthetic or normal saline via the catheter at the iliac crest donor site.
The participants also received IV morphine delivered by a patient-controlled analgesic (PCA) pump. The usual dose was 1 mg with a lock-out interval of 5 minutes. The pumps were read every hour to obtain the cumulative analgesic dose. Oral analgesic consisting of 1 g paracetamol was given routinely every 6 hours. The PCA ceased at 24 or 48 hours after surgery if the patient did not require this form of analgesic. The oral paracetamol continued until discharge. Pain was assessed hourly for the first 24 hours and every 3 hours for the next 24 hours by using the Verbal Numerical Scale. Participants were asked to clearly delineate donor site pain from neck or other pain experienced.
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