Jonna S. Fomsgaard

A Randomized Study of the Effects of Single-dose Gabapentin versus Placebo on Postoperative Pain and Morphine Consumption after Mastectomy

BACKGROUND The anticonvulsant gabapentin has proven effective for neuropathic pain in three large placebo-controlled clinical trials. Experimental and clinical studies have demonstrated antihyperalgesic effects in models involving central neuronal sensitization. It has been suggested that central neuronal sensitization may play an important role in postoperative pain. The aim of the study was to investigate the effect of gabapentin on morphine consumption and postoperative pain in patients undergoing radical mastectomy. METHODS In a randomized, double-blind, placebo-controlled study, 70 patients received a single dose of oral gabapentin (1,200 mg) or placebo 1 h before surgery. Patients received patient-controlled analgesia with morphine at doses of 2.5 mg with a lock-out time of 10 min for 4 h postoperatively. Pain was assessed on a visual analog scale at rest and during movement, and side effects were assessed on a four-point verbal scale 2 and 4 h postoperatively. RESULTS Thirty-one patients in the gabapentin group and 34 patients in the placebo group completed the study. Gabapentin reduced total morphine consumption from a median of 29 (interquartile range, 21-33) to 15 (10-19) mg (P< 0.0001). Pain during movement was reduced from 41 (31-59) to 22 (10-38) mm at 2 h postoperatively (P < 0.0001) and from 31 (12-40) to 9 (3-34) mm at 4 h postoperatively (P = 0.018). No significant differences between groups were observed with regard to pain at rest or side effects. CONCLUSION A single dose of 1,200 mg oral gabapentin resulted in a substantial reduction in postoperative morphine consumption and movement-related pain after radical mastectomy, without significant side effects. These promising results should be validated in other acute pain models involving central neuronal sensitization.

Adductor canal block versus femoral nerve block for analgesia after total knee arthroplasty: a randomized, double-blind study.

Background and Objectives Femoral nerve block (FNB), a commonly used postoperative pain treatment after total knee arthroplasty (TKA), reduces quadriceps muscle strength essential for mobilization. In contrast, adductor canal block (ACB) is predominately a sensory nerve block. We hypothesized that ACB preserves quadriceps muscle strength as compared with FNB (primary end point) in patients after TKA. Secondary end points were effects on morphine consumption, pain, adductor muscle strength, morphine-related complications, and mobilization ability. Methods We performed a double-blind, randomized, controlled study of patients scheduled for TKA with spinal anesthesia. The patients were randomized to receive either a continuous ACB or an FNB via a catheter (30-mL 0.5% ropivacaine given initially, followed by a continuous infusion of 0.2% ropivacaine, 8 mL/h for 24 hours). Muscle strength was assessed with a handheld dynamometer, and we used the percentile change from baseline for comparisons. The trial was registered at clinicaltrials.gov (Identifier: NCT01470391). Results We enrolled 54 patients, of which 48 were analyzed. Quadriceps strength as a percentage of baseline was significantly higher in the ACB group compared with the FNB group: (median [range]) 52% [31–71] versus 18% [4–48], (95% confidence interval, 8–41; P = 0.004). There was no difference between the groups regarding morphine consumption (P = 0.94), pain at rest (P = 0.21), pain during flexion of the knee (P = 0.16), or adductor muscle strength (P = 0.39); neither was there a difference in morphine-related adverse effects or mobilization ability (P > 0.05). Conclusions Adductor canal block preserved quadriceps muscle strength better than FNB, without a significant difference in postoperative pain.

Effects of Adductor-Canal-Blockade on pain and ambulation after total knee arthroplasty: a randomized study

Total knee arthroplasty (TKA) is associated with intense post‐operative pain. Besides providing optimal analgesia, reduction in side effects and enhanced mobilization are important in this elderly population. The adductor‐canal‐blockade is theoretically an almost pure sensory blockade. We hypothesized that the adductor‐canal‐blockade may reduce morphine consumption (primary endpoint), improve pain relief, enhance early ambulation ability, and reduce side effects (secondary endpoints) after TKA compared with placebo.

Analgesic efficacy of ultrasound-guided adductor canal blockade after arthroscopic anterior cruciate ligament reconstruction: a randomised controlled trial.

CONTEXT Anterior cruciate ligament (ACL) reconstruction surgery is associated with moderate to severe postoperative pain, which may be ameliorated by peripheral nerve blocks. The adductor canal block (ACB) is an almost exclusively sensory nerve block that has been demonstrated to reduce pain and opioid consumption after major knee surgery. OBJECTIVES To investigate the analgesic effect of ACB in patients receiving a basic analgesic regimen of paracetamol and ibuprofen after arthroscopic ACL reconstruction under general anaesthesia. DESIGN Randomised, double-blind, placebo-controlled, parallel groups. SETTING Day Case Surgery, University of Copenhagen, Glostrup Hospital, Denmark, June 2010 to March 2012. PATIENTS Fifty patients, aged 18 to 70 years, scheduled for arthroscopic ACL reconstruction. INTERVENTIONS Patients were randomised to receive ACB with either 30 ml ropivacaine 7.5 mg ml−1 (n = 25) or 30 ml 0.9% saline (n = 24). MAIN OUTCOME MEASURES Primary outcome was pain score (0 to 100 mm) during standing at 2 h after surgery. Secondary outcomes were pain at rest, during standing and after walking 5 m, opioid consumption and opioid-related side effects for 24 h after surgery. RESULTS Median (interquartile range) pain scores for the primary outcome were 20 (12 to 36) mm in the ropivacaine and 20 (10 to 44) mm in the control group (P = 0.84, 95% confidence interval for difference of −9 to 12 mm). No significant differences were observed in any of the secondary outcomes. CONCLUSION An analgesic regimen with paracetamol and ibuprofen provides acceptable postoperative pain control after arthroscopic ACL reconstruction. ACB did not confer further benefit in our patients. TRIAL REGISTRATION Clinicaltrials.gov Identifier: NCT01212666.

Intraoperative ketamine reduces immediate postoperative opioid consumption after spinal fusion surgery in chronic pain patients with opioid dependency: a randomized, blinded trial

Abstract Perioperative handling of surgical patients with opioid dependency represents an important clinical problem. Animal studies suggest that ketamine attenuates central sensitization and hyperalgesia and thereby reduces postoperative opioid tolerance. We hypothesized that intraoperative ketamine would reduce immediate postoperative opioid consumption compared with placebo in chronic pain patients with opioid dependency undergoing lumbar spinal fusion surgery. Primary outcome was morphine consumption 0 to 24 hours postoperatively. Secondary outcomes were acute pain at rest and during mobilization 2 to 24 hours postoperatively (visual analogue scale), adverse events, and persistent pain 6 months postoperatively. One hundred fifty patients were randomly assigned to intraoperative S-ketamine bolus 0.5 mg/kg and infusion 0.25 mg·kg−1·h−1 or placebo. Postoperatively, patients received their usual opioids, paracetamol and IV patient-controlled analgesia with morphine. In the final analyses, 147 patients were included. Patient-controlled analgesia IV morphine consumption 0 to 24 hours postoperatively was significantly reduced in the ketamine group compared with the placebo group: 79 (47) vs 121 (53) mg IV, mean difference 42 mg (95% confidence interval −59 to −25), P < 0.001. Sedation was significantly reduced in the ketamine group 6 and 24 hours postoperatively. There were no significant differences regarding acute pain, nausea, vomiting, hallucinations, or nightmares. Back pain at 6 months postoperatively compared with preoperative pain was significantly more improved in the ketamine group compared with the placebo group, P = 0.005. In conclusion, intraoperative ketamine significantly reduced morphine consumption 0 to 24 hours after lumbar fusion surgery in opioid-dependent patients. The trend regarding less persistent pain 6 months postoperatively needs further investigation.

Preoperative dexamethasone reduces acute but not sustained pain after lumbar disk surgery: a randomized, blinded, placebo-controlled trial.

Abstract Glucocorticoids have attracted increasing attention as adjuvants in the treatment of acute postoperative pain. Furthermore, anecdotal reports may support glucocorticoids for preventing sustained postoperative pain. We explored preoperative dexamethasone combined with paracetamol and ibuprofen on acute and sustained pain after lumbar disk surgery. In this blinded study, 160 patients undergoing lumbar disk surgery were randomly assigned to 16 mg IV dexamethasone or placebo. All patients received perioperative paracetamol and ibuprofen, and postoperative IV patient-controlled analgesia with morphine. Primary outcome was pain during mobilization (visual analog scale) 2 to 24 hours postoperatively. Secondary outcomes were acute pain at rest, morphine consumption, nausea, vomiting, ondansetron consumption, sedation, and quality of sleep. Patients were followed up by written questionnaire 3 months postoperatively. Acute pain during mobilization (weighted average area under the curve, 2-24 hours) was significantly reduced in the dexamethasone group: 33 (22) mm vs placebo 43 (18) mm, (95% confidence interval [CI] 3-16) P = 0.005. Vomiting 0 to 24 hours postoperatively was reduced in the dexamethasone group (17 episodes) vs placebo (51 episodes) P = 0.036. No other differences were observed. However, 6.5% (95% CI 2-15) in the dexamethasone group vs placebo 0% had an antibiotically treated wound infection (P = 0.13). Sixteen percent (95% CI 7-26) vs 8% (95% CI 0-17) reported new weakness/paralysis of the legs in the dexamethasone and placebo groups, respectively, 3 months postoperatively (P = 0.20). In conclusion, preoperative dexamethasone significantly reduced pain during mobilization and vomiting, after lumbar disk surgery. No significant effects were observed 3 months postoperatively.

Intraoperative S-ketamine for the reduction of opioid consumption and pain one year after spine surgery: A randomized clinical trial of opioid-dependent patients

We aimed to explore the effect of intraoperative S‐ketamine on analgesic consumption and pain one year after spine surgery in chronic opioid‐dependent patients undergoing spinal fusion surgery.

The effect of chlorzoxazone on acute pain after spine surgery. A randomized, blinded trial

Chlorzoxazone is a muscle relaxant administered for musculoskeletal pain, and as an analgesic adjunct for post‐operative pain. Chlorzoxazone for low back pain is currently not advised due to the lack of placebo‐controlled trials. We explored the effect of chlorzoxazone on acute pain after spine surgery.