Open inguinal hernia repair is typically performed as an outpatient procedure under general, spinal, or local anesthesia (1). Postoperative pain can be severe, causing patient distress and delayed discharge, particularly if local anesthetic blocks are not used (2–8). In our institution, the most common regimen for pain control after herniorrhaphy performed under general anesthesia has been surgeon-administered local anesthetic in the wound at the end of surgery, followed by IV opioids in the recovery unit, and an oral opioid/acetaminophen combination after discharge (9).
Nonsteroidal antiinflammatory drugs (NSAIDs) have typically not been used because of concern that platelet function may be impaired by traditional NSAIDs that inhibit cyclooxygenase (COX)-1 and COX-2. Analgesic effects of NSAIDs are attributed to inhibition of COX-2, an inducible form of the COX enzyme generated in response to tissue trauma and surgery; inhibitory effects on platelet function are attributed to inhibition of COX-1, which is constitutively expressed and present in normal individuals (10). Newer selective COX-2 inhibitors (rofecoxib, valdecoxib, celecoxib), theoretically at least, offer an advantage in the perioperative setting, permitting preemptive administration without impairment of platelet function.
Several studies have demonstrated the efficacy of premedicating ambulatory surgery patients with selective COX-2 inhibitors (11,12). Similarly, local anesthetic blocks before surgery have been shown to reduce pain and analgesic requirements after herniorrhaphy (3,7,13). Thus, it would seem logical to combine the two modalities, even when general anesthesia is elected.
The goal of this study was to determine whether a local anesthetic field block before surgery, alone or in combination with a perioperative COX-2 inhibitor (rofecoxib), would alter the postoperative course of patients having inguinal herniorrhaphy under general anesthesia compared with a standard regimen. The standard regimen consisted of local anesthetic infiltration of the wound at the end of surgery followed by IV opioid and an oral opioid/acetaminophen combination (4). The end-points of the study were postoperative pain scores, analgesic use and side effects, duration of in-hospital recovery, and patient satisfaction.
This proposal was approved by the IRB at the University of Washington. All subjects gave written informed consent to participate. Subjects included 75 patients, aged 18–75 yr, undergoing open inguinal hernia repair under general anesthesia. Patients with a history of alcohol or drug abuse, chronic pain problems, or who had taken opioids or NSAIDs in the previous 24 h were excluded from the study.
Patients were randomly assigned to one of three treatment groups. Group 1 (CONT) was a “standard care” control group that received 10 mL of local anesthetic beneath the external oblique fascia at the end of surgery. Group 2 (PL) received a local anesthetic field block before incision by the technique of Lichtenstein (14). This block entailed a multilayered field block with 30 mL of local anesthetic in the inguinal region before surgery, and 10 mL of local anesthetic injected beneath the external oblique fascia at the end of surgery. There was no attempt to block specific peripheral nerves other than as might occur as part of widespread infiltration. Group 3 (PLR) received rofecoxib 50 mg per os (PO) 30–60 min before surgery and 50 mg PO each morning for 5 days after surgery, in addition to local anesthetic infiltration before and at the end of surgery as in PL. Patients in the CONT and PL groups received a placebo instead of rofecoxib, at comparable times before, and for 5 days after, surgery. The rofecoxib and placebo were prepared in identical gelatin capsules by the hospital pharmacy. The local anesthetic in all instances was a 2:1 mixture (by volume) of 0.5% bupivacaine and 2% lidocaine. The field block (groups PL and PLR) was performed with the aid of an illustrated diagram to ensure consistency of technique. Each group received oral analgesics (oxycodone 5 mg/acetaminophen 325 mg [Percocet®]) for pain after surgery.
All patients received a standardized general anesthetic consisting of premedication with midazolam, 1 mg IV, induction with propofol 3 mg/kg plus 0.5 μg/kg fentanyl, and maintenance by sevoflurane with 60% nitrous oxide. Additional fentanyl, approximately 0.4 μg/kg, was administered for arterial blood pressure increases >10% more than baseline, or heart rate >20% more than baseline. Sevoflurane was titrated to maintain a bispectral index (BIS) of 40–50. Sevoflurane end-tidal gas concentrations and BIS values were recorded at 15-min intervals. Ondansetron 4 mg IV was administered for antiemetic prophylaxis at the end of surgery. The majority of patients (n = 50) breathed spontaneously through a laryngeal mask airway. When tracheal intubation was required (n = 25), paralysis was achieved using succinylcholine 1 mg/kg. Neuromuscular block for surgery, when requested, was provided by vecuronium 0.05 mg/kg with reversal by neostigmine/glycopyrrolate. Postoperatively, pain was treated by IV fentanyl, in 25-μg increments, followed by a combination of oxycodone 5 mg with acetaminophen 325 mg PO (Percocet®). Patients were medicated to achieve a pain score of 3 of 10 or less, or until they reported being “comfortable,” as is routine in our institution. Criteria for discharge included that patients’ pain, nausea, and bleeding were controlled, patients were able to ambulate, and had voided or had their bladder emptied by catheterization. Pain after discharge was managed by Percocet® 1–2 tablets every 4–6 h as required for pain.
Pain scores, on a scale of 0–10 (where 0 = no pain, and 10 = worst pain imaginable), were obtained at 15 min, 30 min, and 30-min intervals thereafter until discharge. Maximum pain before discharge postanesthesia care unit ([PACU] maximum) was obtained by visual inspection of the data. Time to achieve maximum pain varied depending on the speed of awakening as well as other variables. Also recorded were analgesic use and total recovery duration (time to discharge). Data were obtained for the period after discharge by telephone interview at 24 h, 48 h, and 7 days. At least three attempts were made to contact patients at each interval. Information obtained included: 1) pain scores (0–10 scale): maximum (= worst pain), minimum, pain at rest, pain upon rising to a standing position, pain while walking, and pain while coughing; 2) analgesic use; 3) global activity levels (0–100 scale, expressed as a percent of normal); 4) incidence of side effects of surgery and/or analgesics; 5) distress attributed to each side effect (distress scores on a scale of 0–5, 0 = absent, 1 = not bothersome at all, 5 = as bothersome as could be imagined), with a maximum of 70 for all distress scores combined (= composite symptom distress score) (15). Side effects surveyed included pain, nausea, vomiting, dizziness or light-headedness, difficulty concentrating, drowsiness, constipation, diarrhea, abdominal discomfort, dry mouth, pruritus, rash, blurry vision, and difficulty voiding. Patients were also asked to report swelling (absent, mild, or marked) or bleeding at the wound site (absent, minor required no treatment, required dressing change without return to hospital, required return to hospital). Satisfaction scores were obtained at 48 h with regard to pain control in the hospital and at home, and with the overall recovery process (1–6 scale in which 1 = very dissatisfied and 6 = very satisfied). All participating patients, and nurses and research coordinators caring for the patients, were blinded to group assignment throughout the study.
The main end-points of the study were pain scores, rescue analgesic use, and duration of in-hospital recovery. Group means and standard deviations were computed for continuous data, and intergroup comparisons made using analysis of variance, with post hoc testing by Bonferroni-Dunn. An overall α value of 0.05 was set as the level of significance for the study. Nominal P values are reported in the tables for intergroup comparisons. The Kruskal-Wallis and Mann-Whitney tests were used for between-group comparisons of nonparametric data (symptom distress scores, satisfaction scores). Proportions were compared using χ2 or Fisher’s exact test as indicated. A previous study (13) indicated that 38 patients would be required (19 per group) to detect a 2-point difference in maximum pain score (a 34% difference) between treatment and the control group with 80% power at a significance level of 0.05. Therefore, the study was designed to include 25 patients per group.
Demographic factors and details of anesthesia are shown in Table 1. Surgery consisted of a tension-free hernia repair with mesh in all patients, 4 for recurrent hernias, and 71 for primary repair. Twenty attending surgeons participated in the study. Groups PL and PLR received 38% and 31% less fentanyl intraoperatively, respectively, than the CONT group. Time averaged end-tidal sevoflurane concentration was 21% less in the PLR group; BIS values were comparable in all 3 groups. The relationship of pain scores among groups in the PACU (Fig. 1) varied over the course of the first 120 min. Both PL and PLR groups reported lower pain scores than the CONT group in the first 30 min of recovery. Thereafter, pain scores did not differ between the PL and CONT groups. In contrast, pain scores continued to be lower throughout the in-hospital recovery period in the PLR group. Because patients varied in their speed of awakening and attainment of most severe (maximum) pain, the average pain scores in the PACU measured at serial time intervals (Fig. 1) were less than the maximum pain scores in the PACU (Table 2).
Statistical comparisons are shown in Table 2. The lower pain scores before discharge in the PLR group correlated with reduced time to discharge (149 min in PLR versus 187 min in CONT, P = 0.05, or versus 189 min in PL, P = 0.04) (Table 2).
Follow-up was successful in 91% of patients at 24 h, 88% at 48 h, and 75% at 7 days, with no difference among groups in the proportion of patients contacted. Maximum pain scores were lower, and opioid (Percocet®) use was reduced in the PLR group compared with the CONT group at 24 h after discharge, but not at 48 h or 7 days. The PLR group also reported lower symptom distress scores related to pain at 24 h (Table 2). Overall, there was a significant correlation between maximum pain scores and opioid use at 24 h (r = 0.48, P < 0.0001).
Although the PLR group reported lower pain scores and reduced opioid use compared with the CONT group, there were no corresponding differences between groups in the reported activity levels (expressed as a percent of normal) (Table 3). Overall, activity level correlated inversely with maximum pain score (r = −0.48 at 24 h, P < 0.0001; r = −0.55 at 48 h, P < 0.0001). The incidence of pain preventing sleep, and of drowsiness, was less in patients in the PLR group compared with the CONT group in the first 24 h after discharge. Satisfaction scores, surveyed at 48 h, in relation to pain control before and after discharge, and to the overall hospital experience, were higher in the PLR group than in the PL or CONT groups (Table 3).
Bleeding was minimal overall; 1 patient in the PL group required a new dressing application but did not require a return to the hospital. Eight patients had minor bleeding requiring no treatment (3 in CONT, 3 in PL, and 2 in PLR groups). Swelling at the wound site was reported in the majority of patients, but was slightly less common in the PLR group (81% in PLR versus 100% in CONT and 95% in PL groups, P = 0.04). Urinary retention, a relatively common side effect of hernia repairs (2) occurred in 4% of the CONT group, 12% of the PL group, and in none of the PLR group. Similarly, inability to empty the bladder fully at 24 h was reported in 18% of patients in each of CONT and PL groups, but in only 4% of the PLR group (P = 0.07). Neither of these differences in voiding variables was statistically significant.
This study demonstrated a reduction of pain scores and decreased Percocet® use in the first 24 hours after surgery in patients who received rofecoxib plus local anesthetic field block before surgery, as compared with a control group that received neither. Local anesthetic field block alone before surgery, with a combination of bupivacaine and lidocaine, conveyed only a short-term benefit in terms of postoperative pain relief and analgesic use (approximately 30 minutes). Evidence of an improved recovery profile with the combination of preoperative rofecoxib and a field block compared with the control group included a 30% reduction in maximum pain score in PACU, a 20% reduction in the duration of in-hospital stay (38 minutes) on the day of surgery, a 22% reduction in maximum pain score in the first 24 hours after discharge coupled with higher satisfaction scores surveyed at 48 hours. Patients also reported a less frequent incidence of difficulty going to sleep, and of drowsiness in the first 24 hours after surgery.
These results are very similar to those recently reported by Ma et al. (11). The latter group reported lower pain ratings, a shorter in-hospital recovery, and reduced need for rescue analgesics after inguinal hernia repair in patients who received preoperative and postoperative rofecoxib as compared with a placebo-treated control group. Both groups received a preincisional local anesthetic block. Our study differs from the latter in that we included a control group that received only local anesthetic infiltration of the wound at the end of surgery. This control group was included to allow us to evaluate whether improved pain control could be attributed to the preoperative local anesthetic field block alone, and whether rofecoxib contributed additional benefits superimposed on the effects of the local anesthetic block. The analgesic regimen used in the control group was the technique most frequently used before the study in our institution (9). We did not, for ethical reasons, include an untreated control group because almost all patients would normally have received at least some local anesthetic in the wound at the end of surgery. Because we did not include a group that received rofecoxib alone without a preoperative block, our study also does not permit determining how effective rofecoxib alone would be in the absence of local anesthetic.
The current study is somewhat at variance with a report by Tverskoy et al. (7) of superior pain relief for up to 10 days in patients who received a lidocaine field block before inguinal hernia repair. However, in the latter study, significant reduction of pain scores at 10 days was only demonstrable by exerting pressure on the wound (wound tenderness). Wound tenderness to pressure was not specifically assessed in our study. We observed no evidence, however, of reduced incident pain at 48 hours or 7 days using “pain on coughing, walking, or rising” as measures of incident pain.
In a review of the literature relating to pain relief after hernia repair, Callesen and Kehlet (16) concluded that local anesthetic blocks decreased early postoperative pain (for up to 6 hours) and decreased analgesic use. There are conflicting data regarding whether the timing of local anesthetic injection affects pain relief after surgery (17,18). Our study was not designed to compare the effects of preoperative versus postoperative local anesthetic block. The field block performed before surgery was a more complete block using larger volumes of local anesthetic in superficial and deep layers of the wound than the local anesthetic infiltration performed at the end of surgery, which consisted of injecting 10 mL of local anesthetic beneath the aponeurosis of the external oblique muscle.
The preoperative use of other nonselective NSAIDs (mixed COX-1/COX-2 inhibitors such as naproxen or ketorolac) has also been reported to be advantageous in patients having hernia repairs (19,20). In our study, we chose a selective COX-2 inhibitor as an antiinflammatory because of less likelihood, at least theoretically, of causing bleeding (21,22) in the postoperative period. Bleeding from the wound was minimal in all of our patients. Rofecoxib was chosen specifically because of its relatively long duration of action (t1/2 ≈ 17 hours) which permitted once-a-day dosing (23,28), and because preoperative rofecoxib had already been demonstrated to provide improved pain control after ambulatory surgery (24). The speed of onset of analgesic effects has been reported to be 0.7–1.5 hours after dosing (23). In this study, the benefits of rofecoxib were demonstrable only in the first 24 hours after surgery with no evidence of a sustained preemptive effect at 48 hours or 7 days. This may be in part because pain was less intense in all groups after the first 24 hours, making it difficult to show beneficial effects of any treatment beyond that point.
There was also some evidence of reduced requirements for anesthetic drugs (fentanyl and sevoflurane) in patients who received a preincisional block, particularly in the group that also received rofecoxib. The lesser quantities of anesthetic required to maintain apparently comparable depths of anesthesia (equivalent BIS) suggests another potential advantage of using a preoperative field block in addition to a perioperative COX-2 inhibitor. Possibly, the reduction in anesthetic use accounted in part for the more rapid recovery and discharge in the PLR group.
In summary, these data show that the duration of PACU stay, the postoperative pain scores, pain distress scores, and opioid use can be reduced in the first 24 hours after hernia repair by perioperative rofecoxib in patients who have received a preoperative local anesthetic field block in addition to general anesthesia. These improvements in recovery variables were associated with greater satisfaction with pain control and with the overall recovery process when surveyed 48 hours after surgery.
The authors express their gratitude to the following surgeons who graciously agreed to cooperate in the completion of this study: D. Byrd, P. Dellinger, M. Sinanan, G. Jurkovich, E. Bulger, H. Foy, L. Gentilello, T. Pohlman, C. Cornejo, G. Mann, A. Nathens, L. Kao, R. Yeung, W. Ellis, R. Maier, M. Mayo, G. O’Keefe, L. Chang, and to the Anesthesia personnel who agreed to participate in the study.
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