A placebo-controlled randomized clinical trial of perioperative administration of gabapentin, rofecoxib and their combination for spontaneous and movement-evoked pain after abdominal hysterectomy

Through the Lens of Movement-Evoked Pain: A Theoretical Framework of the "Pain-Movement Interface" to Guide Research and Clinical Care for Musculoskeletal Pain Conditions

Over 120 million Americans report experiencing pain in the past 3 months. Among these individuals, 50 million report chronic pain and 17 million report pain that limits daily life or work activities on most days (ie, high-impact chronic pain). Musculoskeletal pain conditions in particular are a major contributor to global disability, health care costs, and poor quality of life. Movement-evoked pain (MEP) is an important and distinct component of the musculoskeletal pain experience and represents an emerging area of study in pain and rehabilitation fields. This focus article proposes the "Pain-Movement Interface" as a theoretical framework of MEP that highlights the interface between MEP, pain interference, and activity engagement. The goal of the framework is to expand knowledge about MEP by guiding scientific inquiry into MEP-specific pathways to disability, high-risk clinical phenotypes, and underlying individual influences that may serve as treatment targets. This framework reinforces the dynamic nature of MEP within the context of activity engagement, participation in life and social roles, and the broader pain experience. Recommendations for MEP evaluation, encompassing the spectrum from high standardization to high patient specificity, and MEP-targeted treatments are provided. Overall, the proposed framework and recommendations reflect the current state of science in this emerging area of study and are intended to support future efforts to optimize musculoskeletal pain management and enhance patient outcomes. PERSPECTIVE: Movement-evoked pain (MEP) is a distinct component of the musculoskeletal pain experience and emerging research area. This article introduces the "Pain-Movement Interface" as a theoretical framework of MEP, highlighting the interface between MEP, pain interference, and activity engagement. Evaluating and treating MEP could improve rehabilitation approaches and enhance patient outcomes.

Efficacy of prolonged intravenous lidocaine infusion for postoperative movement-evoked pain following hepatectomy: a double-blinded, randomised, placebo-controlled trial

BACKGROUND

The analgesic effect of intravenous lidocaine varies with the duration of lidocaine infusion and surgery type. We tested the hypothesis that prolonged lidocaine infusion alleviates postoperative pain in patients recovering from hepatectomy over the first 3 postoperative days.

METHODS

Patients undergoing elective hepatectomy were randomly assigned to receive prolonged i.v. lidocaine treatment or placebo. The primary outcome was incidence of moderate-to-severe movement-evoked pain at 24 h postoperatively. The secondary outcomes included incidence of moderate-to-severe pain during movement and at rest throughout the first 3 postoperative days, postoperative opioid consumption, and pulmonary complications. Plasma lidocaine concentration was also monitored.

RESULTS

We enrolled 260 subjects. Intravenous lidocaine lowered the incidence of moderate-to-severe movement-evoked pain at 24 h and 48 h postoperatively (47.7% vs 67.7%, P=0.001; 38.5% vs 58.5%, P=0.001) and reduced movement-evoked pain scores (3.7 [1.7] vs 4.2 [1.6]; mean difference 0.5 [95% confidence interval {CI}: 0.1-0.9]; P=0.018) and morphine equivalent consumption (47.2 [16.7] mg vs 52.6 [19.2] mg; mean difference 5.4 mg [95% CI: 1.0-9.8]; P=0.016) at 24 h postoperatively. Lidocaine also lowered the incidence of postoperative pulmonary complications (23.1% vs 38.5%; P=0.007). Median plasma lidocaine concentrations were 1.5, 1.9, and 1.1 μg ml^-1 (inter-quartile ranges: 1.1-2.1, 1.4-2.6, and 0.8-1.6, respectively) after bolus injection, at the end of the surgery, and 24 h postoperatively.

CONCLUSIONS

Prolonged intravenous lidocaine infusion reduced the incidence of moderate-to-severe movement-evoked pain for 48 h after hepatectomy. However, the reduction in pain scores and opioid consumption by lidocaine was below the minimal clinically important difference.

CLINICAL TRIAL REGISTRATION

NCT04295330.

Effectiveness of combined pregabalin and celecoxib for treatment of acute postoperative pain: A meta-analysis and systematic review

OBJECTIVE

To estimate the acute analgesic efficacy of combined Pregabalin and Celecoxib after operation via a systematic review and meta-analysis.

METHODS

Studies for inclusion were randomized controlled trials, reporting on relevant outcomes (0-6 hours, 24 hours, 7 days pain scores) with treatment with combined Pregabalin and Celecoxib.

RESULTS

The pooled results from meta-analysis demonstrated that compared with placebo, combined Pregabalin and Celecoxib reduced pain scores at 0 to 6 hours in 3 articles, 24 hours in 5 articles, 7 days in 2 articles (standard mean difference [SMD], -3.10 at 0-6 hours, -2.80 at 24 hours, -1.32 at 7 days, respectively). Combined Pregabalin and Celecoxib could significantly reduce the postoperative narcotic consumption in 3 studies (SMD, -1.99 at 36 hour).

DISCUSSION

This work suggested that combined Pregabalin and Celecoxib were efficacious in reduction of postoperative pain and narcotic requirements after surgery, whereas more trials are needed to further identify the efficacy of combined Pregabalin and Celecoxib in the management of acute postoperative pain.

A Multimodal Pain Management Regimen for Open Treatment of Distal Radius Fractures: A Randomized Blinded Study

BACKGROUND

Adequate pain control is critical after outpatient surgery where patients are not as closely monitored. A multimodal pain management regimen was compared to a conventional pain management method in patients undergoing operative fixation for distal radius fractures. We hypothesized that there would be a decrease in the amount of narcotics used by the multimodal group compared to the conventional pain management group, and that there would be no difference in bone healing postoperatively.

METHODS

Forty-two patients were randomized into 2 groups based on pain protocols. Group 1, the control, received a regional block, acetaminophen, and oxycodone. Group 2 received a multimodal pain regimen consisting of daily doses of pregabalin, celecoxib, and acetaminophen up until postoperative day (POD) #3. They also received a regional block with oxycodone for breakthrough pain.

RESULTS

From POD#3 to week 1, there was a significant increase in oxycodone use in the study group correlating with the point in time when the multimodal regimen was discontinued. The shortened Disabilities of the Arm, Shoulder, and Hand Questionnaire (QuickDASH) scores taken at 2 weeks postoperation showed a significantly lower average score in the study group compared to the control. There was no difference in bone healing.

CONCLUSIONS

The 2 regimens yielded similar pain control after surgery. The rebound increase in narcotic use after the multimodal regimen was discontinued, and significant difference in QuickDASH scores seen at 2 weeks postoperatively supported that multimodal regimens may not necessarily lead to decreased narcotic use in outpatient upper extremity surgery, but in the short term are shown to improve functional status.

Effect of pregabalin on postoperative pain and instrumentation-induced dysuria in patients undergoing percutaneous nephrolithotomy: A prospective randomized, double-blinded placebo-controlled study

Background and Aims

The manipulation of urinary tract, the mandatory requirement of ureteral stenting, and bladder catheterization in patients undergoing percutaneous nephrolithotomy (PCNL) produces significant pain and dysuria postoperatively. The present study compared the efficacy of pregabalin with placebo in attenuation of these symptoms in patients undergoing PCNL.

Material and Methods

This randomized controlled study was conducted in 110 patients of either sex, aged 18-65 years undergoing elective PCNL requiring nephrostomy tube under general anesthesia. Group G (n: 53) received pregabalin 150 mg and Group P received placebo (n: 49) orally 1 h before the anesthetic induction. All the patients received standard anesthetic protocol. Pain at the site of nephrostomy, instrumentation-induced dysuria (IID), anxiety, and sedation scores were recorded at 0 min, 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h, 24 h postoperatively. Hemodynamics, total requirement of rescue analgesia, and incidence of any adverse effects were also noted.

Results

Patients were demographically comparable between the two groups. There is no difference in nephrostomy site pain between the groups at different points of measurements. IID was less with pregabalin at 0 min, 15 min, 30 min, 1 h, and 2 h after extubation (P value < 0.05, 43% in Group G vs. 68% in group P). Severe urgency was seen in 4%, moderate in 31%, and mild in 33% of patients in placebo group. No patient in pregabalin had severe grade of instrumentation-induced dysuria score (P < 0.05). Patients in Group P required more rescue analgesic (P: 0.009). Anxiety scores, sedation scores, and hemodynamic parameters were comparable.

Conclusion

A single dose of 150 mg pregabalin as oral premedication given 1 h before surgery reduced the incidence and intensity of IID compared to placebo in patients undergoing PCNL without significant adverse effects.

Effect of Sufentanil Combined with Gabapentin on Acute Postoperative Pain in Patients Undergoing Intraspinal Tumor Resection: Study Protocol for a Randomized Controlled Trial

Purpose

Patients undergoing intraspinal tumor resection usually experience severe postoperative pain. Inadequate postoperative analgesia usually leads to severe postsurgical pain, which could cause patients to suffer from many other related complications. Recently, an increasing number of studies have found that gabapentin can relieve hyperalgesia, postoperative pain, and postoperative inflammation. However, there have been no reports on the use of gabapentin combined with sufentanil preoperatively for acute pain following intraspinal tumor resection.

Study Design and Methods

This is a protocol for a randomized, placebo-controlled, and double-blinded trial. One-hundred and sixty-eight participants with chronic pain related to the intraspinal tumor will be randomized into the gabapentin and placebo groups in a 1:1 ratio. In the gabapentin group, patients will be given 300 mg gabapentin orally 36 h, 24 h, and 12 h before surgery; the placebo group will receive a placebo orally at the same time points preoperatively. To estimate the efficacy and safety endpoints, all the researchers and patients will be blinded until the completion of this study. The primary outcome will be the consumption of sufentanil within 48 h postoperatively. The secondary outcomes include the visual analog scale pain score and Von Frey mechanical pain threshold 36 h and 24 h before and 24 h and 48 h after surgery, the incidence of postoperative nausea, vomiting, and drowsiness, the length of hospital stay and medical expenses.

Discussion

This trial is to evaluate the efficacy and safety of gabapentin combined with sufentanil for postoperative analgesia in patients who complain of pain before intraspinal tumor resection. The findings will provide a new strategy for multimode perioperative analgesia management in these patients.

Impact of Gabapentin on PACU Length of Stay and Perioperative Intravenous Opioid Use for ERAS Hysterectomy Patients

We investigated the impact of preoperative gabapentin on perioperative intravenous opioid requirements and post anesthesia care unit length of stay (PACU LOS) for patients undergoing laparoscopic and vaginal hysterectomies within an Enhanced Recovery After Surgery (ERAS) pathway. A multidisciplinary team retrospectively examined 2,015 patients who underwent laparoscopic or vaginal hysterectomies between October 2016 and January 2020 at a single academic institution. The average PACU LOS was 168 min among patients who did not receive gabapentin vs. 180 min both among patients who received ≤ 300 mg of gabapentin and patients who received > 300 mg of gabapentin. After adjusting for demographics and medical comorbidities, PACU LOS for patients given ≤ 300 mg gabapentin was 6% longer (rate ratio (RR) = 1.06, 95% CI = 1.01-1.11) than for patients who were not given gabapentin, and for patients who received > 300 mg of gabapentin was 7% longer (RR = 1.07, 95%CI = 1.01-1.13) than for those who did not receive gabapentin. Patients who received ≤ 300 mg gabapentin received 9% less perioperative intravenous hydromorphone than patients who did not receive gabapentin (RR = 0.91, 95% CI = 0.86 - 0.97); patients who received > 300 mg of gabapentin received 12% less perioperative intravenous hydromorphone than patients who did not receive gabapentin (RR = 0.88, 95% CI = 0.82 - 0.95). These findings represent an absolute difference of 0.09 mg intravenous hydromorphone. There were no statistically significant differences in total intravenous fentanyl received. Preoperative gabapentin given as part of an ERAS pathway is associated with statistically but not clinically significant increases in PACU LOS and decreases in total perioperative intravenous opioid use.

Effect of Pregabalin on the Median Effective Plasma Concentration of Intravenous Alfentanil in Capsaicin-Induced Pain

OBJECTIVE

To apply the sequential up-down method to a human experimental pain model in order to examine the opioid-sparing effect of oral pregabalin on intravenous alfentanil.

DESIGN

Double-blind, randomized, crossover.

SETTING

Academic university medical center.

SUBJECTS

Thirty-one healthy males.

METHODS

The median effective plasma concentration of intravenous alfentanil was determined under two conditions: alfentanil alone (phase I) and alfentanil+ pregabalin (300 mg orally) (phase II). The alfentanil plasma level (after a computer-controlled infusion) producing a success criterion (at least 30% intradermal capsaicin-induced pain reduction compared with placebo) was used to determine higher or lower doses for each sequential subject. The median dose producing a success criterion and its confidence interval were determined.

RESULTS

On the basis of the t test for a difference across phase and regression coefficients across groups, there was no opioid-sparing effect of pregabalin on alfentanil. Four subjects in phase I and five subjects in phase II did not complete the study. Two in phase I were technical failures, with the rest in both phases stopped because of side effects. Of the subjects who completed the study, six of 19 subjects in phase I and 11 of 12 subjects in phase II reported side effects.

CONCLUSIONS

When the intradermal capsaicin-induced pain model was used in healthy volunteers, oral pregabalin had no opioid-sparing effects on intravenous alfentanil. This experimental model may be useful in studying analgesic interactions.

What's New in Pain Management for Pediatric Orthopaedic Surgery

BACKGROUND

Improving pain control and decreasing opioid prescription and usage continue to be emphasized across both pediatric and adult populations. The purpose of this review is to provide a comprehensive assessment of recent literature and highlight new advancements pertaining to pain control in pediatric orthopaedic surgery.

METHODS

An electronic search of the PubMed database was performed for keywords relating to perioperative pain management of pediatric orthopaedic surgery. Search results were filtered by publication date for articles published between January 1, 2015 and December 1, 2020 and yielded 404 papers.

RESULTS

A total of 32 papers were selected for review based upon new findings and significant contributions in the following categories: risk factors for increased opioid usage, opioid overprescribing and disposal, nonpharmacologic interventions, nonsteroidal anti-inflammatory drugs, peripheral nerve blocks, spine surgery specific considerations, surgical pathway modifications, and future directions.

CONCLUSIONS

There have been many advances in pain management for pediatric patients following orthopaedic surgery. Rapid recovery surgical care pathways are associated with shorter length of stay and improved pain control in pediatric spine surgery. Opioid overprescribing continues to be common and information regarding safe opioid disposal practices should be routinely provided for pediatric patients undergoing surgery.

LEVEL OF EVIDENCE

Level IV-literature review.

Toward Understanding Movement-evoked Pain (MEP) and its Measurement: A Scoping Review

OBJECTIVE

Individuals with chronic pain conditions often report movement as exacerbating pain. An increasing number of researchers and clinicians have recognized the importance of measuring and distinguishing between movement-evoked pain (MEP) and pain at rest as an outcome. This scoping review maps the literature and describes MEP measurement techniques.

MATERIALS AND METHODS

The scoping review utilized 6 databases to identify original studies that targeted pain or movement-related outcomes. Our search returned 7322 articles that were screened by title and abstract by 2 reviewers. The inclusion criteria focused on the measurement of MEP before, during, and after movement tasks in adults with chronic pain. Studies of children below 18 years of age or with nonhuman animals, case studies, qualitative studies, book chapters, cancer-related pain, non-English language, and abstracts with no full publish text were excluded from the study.

RESULTS

Results from 38 studies revealed great variation in the measurement of MEP, while almost all of the studies did not provide an explicit conceptual or operational definition for MEP. In addition, studies collectively illuminated differences in MEP compared with rest pain, movement provocation methods, and pain intensity as the primary outcome.

DISCUSSION

These results have clinically significant and research implications. To advance the study of MEP, we offer that consistent terminology, standardized measurement (appropriate for pain type/population), and clear methodological processes be provided in research publications. On the basis of the findings, we have put forth a preliminary definition of MEP that may benefit from the continued scholarly dialog.

Preemptive Analgesia with a Second Dose of Pregabalin, Acetaminophen, Naproxen, and Dextromethorphan: A Comparative Clinical Trial in Major Surgeries

Background

Postoperative pain management can improve patients’ quality of life and decrease hospitalization rates. Preemptive analgesia may provide an effective approach for both pain control and opioid consumption decrease. A common approach for pain management after surgery is to relieve the pain that has already occurred.

Objectives

The aim of this clinical trial was to compare the preemptive analgesic effect of single-dose versus two-dose administration of pregabalin, acetaminophen, naproxen, and dextromethorphan (PAND) combination.

Methods

This study involved 60 patients who had undergone one surgery (including nephrectomy, cystectomy, prostatectomy, colectomy, Whipple, and RPLND). They were randomly divided into two groups: The first group received a single dose of PAND, while the other group received a second dose within 6 hours after discharge from recovery. Pain intensity was assessed by the Universal Pain Assessment Tool (UPAT) in both groups 2, 4, 6, 8, 12, 24, and 48 hours postoperatively. The postoperative morphine dose in both groups was also recorded. Data were analyzed using SPSS version 25.

Results

Mean pain scores were significantly different between the two groups at 2, 12, 24, and 48 hours after surgery (P < 0.05). There was a statistically significant difference between the two groups in terms of opioid consumption (P < 0.001). The total opioid consumption in the second group (with the second administration of PAND) was lower than the first group.

Conclusions

Preemptive analgesia with a second dose of PAND is an effective method for reducing pain and morphine consumption after surgery.

The effect of a single 75 mg preoperative dose of pregabalin on postoperative pain in rhinoplasty: A double-blinded, placebo-controlled randomized clinical trial

The goal of this study was to evaluate the effect of a single preoperative dose of 75 mg of pregabalin on postoperative pain in rhinoplasty. Volunteers with a physical status of ASA I were included in our study after informed written consent. This was a randomized, double-blinded, placebo-controlled clinical trial. All pregabalin and placebo capsules were given to patients orally 1 h prior to surgery. A standard open rhinoplasty procedure was performed on all patients. All patients underwent the same general anesthesia and postoperative analgesic protocol, with the only difference between the two studied groups being the use of a single dose of pregabalin prior to surgery. Finally, pain intensity was measured at 2, 4, 6, 12, and 24 h after surgery, using a horizontal visual analogue scale (VAS), and was analyzed statistically. 128 volunteers - 33 men (25.8%) and 95 women (74.2%) - with a mean age of 26.23 ± 7.16 were included in this study. Pain intensity scores were consistently lower in patients who received pregabalin preoperatively (p = 0.002); however, the incidence of nausea, drowsiness, difficulty in concentrating, dry mouth, and constipation showed no differences between the two study groups (p > 0.05). In conclusion, the administration of pregabalin should be added to the perioperative protocol whenever appropriate.

Postoperative pain management in obstetrics and gynecology

The efficiency and quality of postoperative pain management may be considered unsatisfactory in Europe, as well as in the United States. Notwithstanding our better understanding of the physiology of pain and the development of new analgesia procedures, the improvement in satisfaction of patients has not be enhanced to the same degree. Obstetrics and gynecology are no exception to this statement. In fact, obstetrics and gynecology are surgical departments in which patients experience the greatest severity of postoperative pain. Current concepts of postoperative pain management are largely based on the administration of systemic non-opioid and opioid analgesics, supplemented with regional analgesia procedures and/or peripheral nerve blockades and, in some cases, the administration of other pain-relieving pharmaceutical agents. Based on the existing body of evidence, it would be appropriate to develop procedure-related concepts of analgesia. The concepts are based on the special circumstances of the respective department, and the scheme of analgesia is aligned to the respective interventions. Generally, however, a surgeon’s individual experience in dealing with the procedures and substances could be more significant than the theoretical advantages demonstrated in preceding investigations.

Safety in Acute Pain Medicine-Pharmacologic Considerations and the Impact of Systems-Based Gaps

Objective

In the setting of an expanding prevalence of acute pain medicine services and the aggressive use of multimodal analgesia, an overview of systems-based safety gaps and safety concerns in the setting of aggressive multimodal analgesia is provided below.

Setting

Expert commentary.

Methods

Recent evidence focused on systems-based gaps in acute pain medicine is discussed. A focused literature review was conducted to assess safety concerns related to commonly used multimodal pharmacologic agents (opioids, nonsteroidal anti-inflammatory drugs, gabapentanoids, ketamine, acetaminophen) in the setting of inpatient acute pain management.

Conclusions

Optimization of systems-based gaps will increase the probability of accurate pain assessment, improve the application of uniform evidence-based multimodal analgesia, and ensure a continuum of pain care. While acute pain medicine strategies should be aggressively applied, multimodal regimens must be strategically utilized to minimize risk to patients and in a comorbidity-specific fashion.

Current Status and Future Directions of Pain-Related Outcome Measures for Post-Surgical Pain Trials

Background: Clinical trials remain vital in order to: A) develop new treatment interventions, and also, B) to guide optimal use of current interventions for the treatment and prevention of acute and chronic postsurgical pain. Measures of pain (e.g. intensity and relief) and opioid use have been validated for the settings of postsurgical pain and continue to effectively guide research in this field..

Methods: This narrative review considers needs for innovation in postsurgical pain trial outcomes assessment.

Results: Future improvements are needed and include: A) more widespread measurement of movement-evoked pain with validation of various procedure-relevant movemen-tevoked pain maneuvers; B) new validated analytical approaches to integrate early postoperative pain scores with opioid use; and, C) closer attention to the measurement of postoperative opioid use after hospital discharge. In addition to these traditional measures, consideration is being given to the use of new pain-relevant outcome domains that include: 1) other symptoms (e.g. nausea and vomiting), 2) recovery of physiological function (e.g. respiratory, gastrointestinal, genitourinary and musculoskeletal), 3) emotional function (e.g. depression, anxiety) and, 4) development of chronic postsurgical pain. Also, there is a need to develop pain-related domains and measures for evaluating both acute and chronic post-operative pain. Finally, evidence suggests that further needs for improvements in safety assessment and reporting in postsurgical pain trials is needed, e.g. by using an agreed upon, standardized collection of outcomes that will be reported as a minimum in all postsurgical pain trials.

Conclusions: These proposed advances in outcome measurement methodology are expected to improve the success by which postsurgical pain trials guide improvements in clinical care and patient outcomes.

The use of 5% lidocaine medicated plaster for acute postoperative pain after gynecological surgery: A pilot randomized controlled feasibility trial

OBJECTIVES

To examine the feasibility and potential efficacy of 5% lidocaine medicated plaster for acute postoperative pain in a parallel, blinded, randomized controlled pilot trial.

METHODS

Twenty-eight women undergoing elective gynecological surgery with midline incisions were randomly allocated 5% lidocaine medicated patch (Lignopad) or placebo plasters. Postoperative pain at rest and on movement at 24 hours were the primary study endpoints, with secondary endpoints of postoperative pain within the first 48 hours, cumulative morphine consumption (mg), predicted peak flow rate (PFR) (%) and adverse effects. We assessed pain scores at rest and on movement using the visual analogue scale (0-100).

RESULTS

The lidocaine patch group had lower postoperative pain scores at rest at 24 hours (mean difference [MD] -15.1, 95% confidence interval [95% CI] -28.3 to -2.0; P = .024) but not on movement at 24 hours (MD -6.4, 95% CI -22.7 to 9.9; P = .445). Compared to placebo, lidocaine may slightly lower cumulative morphine consumption (mg) over time (MD -3.4, 95% CI -6.9 to 0.2; group*time interaction P = .065). The difference in improvement in the PFR over time after surgery between groups appeared small (group*time P = .0980). No adverse effects occurred.

CONCLUSIONS

Lidocaine patch may provide a clinically important reduction in postoperative pain intensity. A larger trial to confirm the efficacy and safety of lidocaine patch is feasible after modifying the inclusion criteria and collecting patient-centered outcomes, such as quality of recovery and patient satisfaction.

Utility of gabapentin in meeting physical therapy goals following posterior spinal fusion in adolescent patients with idiopathic scoliosis

OF BACKGROUND DATA

Posterior spinal fusion surgery for scoliosis requires extensive postoperative analgesic care. In 2014, we initiated the use of gabapentin as an adjunct for multimodal pain management in spine fusion patients. The effect of gabapentin on postoperative recovery in scoliosis patients was evaluated using the time to meet postoperative physical therapy goals. This measure was chosen because the actions required to achieve the goals are specific and reproducible. Secondary outcomes included morphine equivalents and maximum pain scores.

AIMS

The purpose of this study was to evaluate the effects of gabapentin on time to achieve physical therapy goals following posterior spinal fusion in adolescents with scoliosis.

METHODS

A retrospective chart review was performed and patients treated perioperatively with gabapentin were compared with those who did not receive gabapentin. Outcome measures included the postoperative day that physical therapy goals were met, days to discharge, morphine equivalents, and maximum pain scores. The 4 physical therapy goals included logroll, transition from lying to sitting, ambulate 250 feet, and ascend/descend at least 3 stairs.

RESULTS

There were 50 patients in the gabapentin group and 51 patients in the control group. In the gabapentin group, there was a statistically significant decrease in the time required to meet physical therapy goals. Notably, gabapentin was independently associated with a 5.34 times higher odds of completion of the most challenging physical therapy goal (stairs) within 1 day (P = .04; 95% CI=1.24-37.44). There was not a statistically significant difference in length of hospital stay between the groups (P = .116; 95% CI=0-1).

CONCLUSION

In this retrospective analysis, the use of perioperative gabapentin is associated with a statistically significant decrease in time to completing physical therapy goals after spinal fusion for adolescent idiopathic scoliosis.

Current methods and challenges for acute pain clinical trials

This article reviews current methods and challenges and provides recommendations for future design and conduct of clinical trials of interventions to treat acute pain.

Introduction:

The clinical setting of acute pain has provided some of the first approaches for the development of analgesic clinical trial methods.

Objectives:

This article reviews current methods and challenges and provides recommendations for future design and conduct of clinical trials of interventions to treat acute pain.

Conclusion:

Growing knowledge about important diverse patient factors as well as varying pain responses to different acute pain conditions and surgical procedures has highlighted several emerging needs for acute pain trials. These include development of early-phase trial designs that minimize variability and thereby enhance assay sensitivity, minimization of bias through blinding and randomization to treatment allocation, and measurement of clinically relevant outcomes such as movement-evoked pain. However, further improvements are needed, in particular for the development of trial methods that focus on treating complex patients at high risk of severe acute pain.

Comparison of ultrasound-guided posterior transversus abdominis plane block and lateral transversus abdominis plane block for postoperative pain management in patients undergoing cesarean section: a randomized double-blind clinical trial study

Background

Due to the importance of pain control after abdominal surgery, several methods such as transversus abdominis plane (TAP) block are used to reduce the pain after surgery. TAP blocks can be performed using various ultrasound-guided approaches. Two important approaches to do this are ultrasound-guided lateral and posterior approaches. This study aimed to compare the two approaches of ultrasound-guided lateral and posterior TAP blocks to control pain after cesarean section.

Materials and methods

In this double-blind clinical trial study, 76 patients scheduled for elective cesarean section were selected and randomly divided into two groups of 38 and underwent spinal anesthesia. For pain management after the surgery, one group underwent lateral TAP block and the other group underwent posterior TAP block using 20cc of ropivacaine 0.2% on both sides. Pain intensity was evaluated based on Numerical Analog Scale (NAS) at rest and when coughing, 2, 4, 6, 12, 24 and 36 hours after surgery.

Results

The pain at rest in the posterior group at all hours post surgery was lower than the lateral group, especially at 6, 12 and 24 hours after the surgery and the difference was statistically significant (p=0.03, p<0.004, p=0.001).

Conclusion

The results of this study show that ultrasound-guided posterior TAP block compared with the lateral TAP block was more effective in pain control after cesarean section.

Dose-related beneficial and harmful effects of gabapentin in postoperative pain management - post hoc analyses from a systematic review with meta-analyses and trial sequential analyses

Background

During the last 15 years, gabapentin has become an established component of postoperative pain treatment. Gabapentin has been employed in a wide range of doses, but little is known about the optimal dose, providing the best balance between benefit and harm. This systematic review with meta-analyses aimed to explore the beneficial and harmful effects of various doses of gabapentin administered to surgical patients.

Materials and methods

Data in this paper were derived from an original review, and the subgroup analyses were predefined in an International Prospective Register of Systematic Reviews published protocol: PROSPERO (ID: CRD42013006538). The methods followed Cochrane guidelines. The Cochrane Library’s CENTRAL, PubMed, EMBASE, Science Citation Index Expanded, Google Scholar, and FDA database were searched for relevant trials. Randomized clinical trials comparing gabapentin versus placebo were included. Four different dose intervals were investigated: 0–350, 351–700, 701–1050, and >1050 mg. Primary co-outcomes were 24-hour morphine consumption and serious adverse events (SAEs), with emphasis put on trials with low risk of bias.

Results

One hundred and twenty-two randomized clinical trials, with 8466 patients, were included. Sixteen were overall low risk of bias. No consistent increase in morphine-sparing effect was observed with increasing doses of gabapentin from the trials with low risk of bias. Analyzing all trials, the smallest and the highest dose subgroups demonstrated numerically the most prominent reduction in morphine consumption. Twenty-seven trials reported 72 SAEs, of which 83% were reported in the >1050 mg subgroup. No systematic increase in SAEs was observed with increasing doses of gabapentin.

Conclusion

Data were sparse, and the small number of trials with low risk of bias is a major limitation for firm conclusions. Taking these limitations into account, we were not able to demonstrate a clear relationship between the dosage of gabapentin and opioid-sparing or harmful effects. These subgroup analyses are exploratory and hypothesis-generating for future trialists.

Perioperative Gabapentin Does Not Reduce Postoperative Delirium in Older Surgical Patients: A Randomized Clinical Trial

BACKGROUND

Postoperative pain and opioid use are associated with postoperative delirium. We designed a single-center, randomized, placebo-controlled, parallel-arm, double-blinded trial to determine whether perioperative administration of gabapentin reduced postoperative delirium after noncardiac surgery.

METHODS

Patients were randomly assigned to receive placebo (N = 347) or gabapentin 900 mg (N = 350) administered preoperatively and for the first 3 postoperative days. The primary outcome was postoperative delirium as measured by the Confusion Assessment Method. Secondary outcomes were postoperative pain, opioid use, and length of hospital stay.

RESULTS

Data for 697 patients were included, with a mean ± SD age of 72 ± 6 yr. The overall incidence of postoperative delirium in any of the first 3 days was 22.4% (24.0% in the gabapentin and 20.8% in the placebo groups; the difference was 3.20%; 95% CI, 3.22% to 9.72%; P = 0.30). The incidence of delirium did not differ between the two groups when stratified by surgery type, anesthesia type, or preoperative risk status. Gabapentin was shown to be opioid sparing, with lower doses for the intervention group versus the control group. For example, the morphine equivalents for the gabapentin-treated group, median 6.7 mg (25th, 75th quartiles: 1.3, 20.0 mg), versus control group, median 6.7 mg (25th, 75th quartiles: 2.7, 24.8 mg), differed on the first postoperative day (P = 0.04).

CONCLUSIONS

Although postoperative opioid use was reduced, perioperative administration of gabapentin did not result in a reduction of postoperative delirium or hospital length of stay.

Preemptive analgesia for postoperative hysterectomy pain control: systematic review and clinical practice guidelines

OBJECTIVE

The objective of the study was to investigate the effectiveness of preemptive analgesia at pain control in women undergoing total abdominal hysterectomy.

DATA SOURCES

Eligible studies, published through May 31, 2016, were retrieved through Medline, Cochrane Central Register for Controlled Trials, and Cochrane Database of Systematic Reviews.

STUDY ELIGIBILITY

We included randomized controlled trials with the primary outcome of pain control in women receiving a preemptive medication prior to total abdominal hysterectomy. Comparators were placebo, different doses of the same medication as intervention, or other nonnarcotic or narcotic medication.

STUDY APPRAISAL AND SYNTHESIS METHODS

Study data were extracted by one reviewer and confirmed by a second reviewer. For each outcome we graded the quality of the evidence. Studies were classified by the type of medication used and by outcome type.

RESULTS

Eighty-four trials met eligibility, with 69 included. Among nonnarcotic medications, paracetamol, gabapentin, and rofecoxib combined with gabapentin resulted in improvements in pain assessment compared with placebo and other nonnarcotic medications. Patient satisfaction was higher in patients who were given gabapentin combined with paracetamol compared with gabapentin alone. Use of preemptive paracetamol, gabapentin, bupivacaine, and phenothiazine resulted in less narcotic usage than placebo. All narcotics (ketamine, morphine, fentanyl) resulted in improved pain control compared with placebo. Narcotics had a greater reduction in pain assessment scores compared with nonnarcotics, and their use resulted in lower total narcotic usage.

CONCLUSION

Preemptive nonnarcotic and narcotic medications prior to abdominal hysterectomy decrease total narcotic requirements and improve patient postoperative pain assessment and satisfaction scores.

Decreasing postoperative narcotics in reconstructive pelvic surgery: a randomized controlled trial

BACKGROUND

Postoperative pain control is crucial to any successful recovery plan. Many currently used medication regimens are narcotic-focused.

OBJECTIVE

The objective of our study was to evaluate the efficacy of a multimodal pain regimen after pelvic reconstructive surgery.

STUDY DESIGN

The primary outcome measure was narcotic use. Secondary outcomes included pain, nausea, and constipation. Patients were randomized to either usual care postoperative treatment or multimodal pain regimen. Usual care included no specific preoperative or intraoperative medications, and postoperative narcotics with ibuprofen. Multimodal pain regimen included preoperative and postoperative celecoxib, gabapentin, intraoperative and postoperative intravenous and oral acetaminophen and ibuprofen, and narcotics as needed. All narcotics were converted to milligram equivalents of oral morphine for standardization according to Centers for Disease Control and Prevention guidelines where conversion factors for oral hydrocodone = 1, oral oxycodone = 1.5, and oral hydromorphone = 4. Patients were given the validated Brief Pain Inventory survey preoperatively (baseline), at postoperative day 1, and 1 week postoperatively. At 1 week, bowel function and narcotics usage was assessed.

RESULTS

Seventy patients were randomized to the usual care arm and 68 to the multimodal pain regimen arm. Patients in the multimodal pain regimen arm used significantly fewer intravenous narcotics in the operating room (90.7 ± 39.1 mg vs 104.6 ± 33.5 mg; P = .026) and while in the hospital (10.8 ± 15.1 mg vs 31.2 ± 29.6 mg; P < .001) and were more likely to use 0 oral narcotics after discharge to home (34.8% of patients vs 10.6%; P = .001). Of the patients who did use oral narcotics after discharge to home, there was no difference in amount used between groups (121.3 ± 103.7 mg in the multimodal pain regimen arm vs 153.0 ± 113.8 mg in the usual care arm; P = .139). Total narcotic usage (operating room + hospital + home) was significantly less in the multimodal pain regimen arm of the study (195.5 ± 147.2 mg vs 304.0 ± 162.1 mg; P < .001). There were no significant differences in pain scores between the 2 arms of the study on either postoperative time point. There were no significant differences in antiemetic use while in hospital, consistency of first bowel movement, length of stay, or number of telephone calls to nurses in first 3 weeks postoperatively.

CONCLUSION

A multimodal pain regimen in pelvic reconstructive surgery was found to decrease postoperative opioid requirements, while providing equivalent pain control.

Comparison of patient-controlled intravenous analgesia with sufentanil versus tramadol in post-cesarean section pain management and lactation after general anesthesia - a prospective, randomized, double-blind, controlled study

Introduction

Acute pain is a common complication following cesarean section under general anesthesia. Post–cesarean section pain management is important for both the mother and the newborn. This study compared the effects of patient-controlled intravenous analgesia (PCIA) using sufentanil or tramadol on postoperative pain control and initiation time of lactation in patients who underwent cesarean section under general anesthesia.

Methods

Primiparas (n=146) scheduled for cesarean section under general anesthesia were randomized to receive PCIA with sufentanil or tramadol. Movement-evoked and rest-pain intensity were assessed by the Numerical Rating Scale (NRS) postoperatively. The number of PCIA attempts, amount of drug consumed, initiation time of lactation, and Quality of Recovery Score 40 (QoR-40) were recorded at 4, 8, 12, and 24 h postoperatively. Pre- and postoperative serum prolactin levels were recorded.

Results

No between-group difference existed in the NRS at rest at any time point postoperatively. Patients on sufentanil had more movement-evoked pain and a higher sedation score at 4, 8, and 12 h postoperatively, as compared with the tramadol group. At 24 h, the QoR-40 was higher in the tramadol group compared with the sufentanil group. No significant between-group differences were present in patient satisfaction and nausea/vomiting scores. Postpartum prolactin levels were significantly higher in the tramadol group versus the sufentanil group, corresponding with a significant delay in initiation of lactation in the latter.

Conclusion

PCIA with tramadol may be preferred due to lower movement-evoked pain, higher quality of recovery, and earlier lactation in patients following cesarean section under general anesthesia.

Gabapentin in procedure-specific postoperative pain management - preplanned subgroup analyses from a systematic review with meta-analyses and trial sequential analyses

Background

It has been argued that postoperative pain treatment should be “procedure-specific”, since different analgesics may have specific effects dependent on the surgical procedure. The aim of the present subgroup analysis was to compare the beneficial and harmful effects of perioperative gabapentin treatment in different surgical procedures.

Methods

Relevant databases were searched for randomized clinical trials (RCTs) comparing gabapentin versus placebo. Two authors independently screened titles and abstracts, extracted data and assessed risk of bias. The primary outcomes were differences in 24-h morphine consumption, and serious adverse events (SAE) between surgical procedures. These subgroup analyses were predefined in a PRISMA compliant systematic review registered at PROSPERO (ID: CRD42013006538). It was predefined that conclusions should primarily be based on trials classified as overall low risk of bias.

Results

Seventy-four RCTs with 5645 patients were included, assessing benefit and harm in cholecystectomy, hysterectomy, mastectomy, and arthroplasty surgery, spinal surgery, and thoracic surgery.

Only eight of 74 trials were classified as overall low risk of bias limiting our ability to conclude on the estimates in most meta-analyses. The differences between surgical procedures in these trials were not statistically significant when tested for subgroup differences. Fifteen trials with 1377 patients reported a total of 59 SAEs, most of which were observed in the thoracic surgery group.

Conclusion

Both beneficial and harmful effects in these subgroup analyses were influenced by bias and insufficient data, limiting conclusions. With these limitations, we could not adequately test for differences in beneficial or harmful outcomes between six surgical subgroups undergoing perioperative gabapentin treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0373-8) contains supplementary material, which is available to authorized users.

The Effect of Gabapentin on Delayed Discharge from the Postanesthesia Care Unit: A Retrospective Analysis

BACKGROUND

Enhanced recovery after surgery programs has incorporated gabapentin as part of a multimodal analgesia protocol. The preemptive use of gabapentin was found to be beneficial due to its opioid-sparing effect. However, excessive sedation and delayed discharge from postanesthesia recovery units are of concern. The aim of this study was to investigate whether preoperative gabapentin increased the length of stay in the recovery unit.

METHODS

This retrospective cross-sectional study was carried out over a period of 2 months in the postanesthesia care unit (PACU) of a tertiary care hospital in Canada. Two hundred and twenty-eight consecutive patients who underwent elective surgical procedures and who required a longer than 2-hour stay in the PACU were included. Prolonged stays caused by respiratory inadequacy, hemodynamic instability, nausea, vomiting, pain, and loss of consciousness were recorded. The data were collected from patients' charts and nursing flow sheets.

RESULTS

All patients were grouped into those who received 300 mg gabapentin (n = 108), 600 mg gabapentin (n = 41), and no gabapentin (n = 139). No significant difference was observed between the groups in terms of opioid consumption, respiratory inadequacy, nausea, vomiting, and hemodynamic parameters. Gabapentin administration groups had significantly lower postoperative pain scores (P < 0.001). Decreased level of consciousness occurred significantly more often in a dose-dependent fashion in the gabapentin groups and led to a longer stay in the PACU (P < 0.001).

CONCLUSION

In the setting of enhanced recovery after surgery, gabapentin did reduce pain scores, but at the cost of delayed discharge from the recovery room. Future studies are needed to evaluate the efficacy of gabapentin in this setting.

Methodology for self-report of rest pain (or spontaneous pain) vs evoked pain in chronic neuropathic conditions: a prospective observational pilot study

This pilot study provides evidence supporting the feasibility and validity of new self-report methodology for the assessment of rest vs evoked pain in chronic neuropathic conditions. Future confirmatory studies will further expand this field and facilitate important improvements in the research and development of new treatments for chronic pain.

Introduction:

The distinction between pain at rest and pain evoked by touch or movement has important clinical implications and may be associated with different mechanisms. However, current methods of clinical pain assessment pay little attention to directly distinguishing between these contrasting components of symptom burden.

Objectives:

We developed the 10-item “Functional Impact of Neuropathic Evoked and Spontaneous Symptom Evaluation” questionnaire designed to distinguish between rest and evoked pain.

Methods:

A prospective observational pilot study of this questionnaire was conducted in 78 participants with neuropathic pain diagnoses. Other study measures included the self-report version of the Leeds Assessment of Neuropathic Symptoms and Signs questionnaire and a modified Brief Pain Inventory. Exploratory analyses were conducted to evaluate the validity of the Functional Impact of Neuropathic Evoked and Spontaneous Symptom Evaluation questionnaire.

Results:

Pain symptoms often/very often/always (1) evoked by touch or movement, and (2) occurring at rest without tactile stimulation were reported by 81% and 65%, respectively. Evoked pain was associated with walking (64%) and standing (35%); and rest pain was associated with watching television (47%), reading (37%), and sitting (36%). Participants reporting both rest and evoked pain tended to report higher levels of pain interference compared to those reporting evoked pain only.

Discussion:

These results provide support for the feasibility and validity of new patient-report methods to distinguish between rest pain and evoked pain in chronic neuropathic conditions. Future studies are needed to confirm the reliability and validity of these methods, which may facilitate important improvements in the research and development of new treatments for chronic pain.

Gabapentin Does Not Appear to Improve Postoperative Pain and Sleep Patterns in Patients Who Concomitantly Receive Regional Anesthesia for Lower Extremity Orthopedic Surgery: A Randomized Control Trial

In recent years, gabapentin has gained popularity as an adjuvant therapy for the treatment of postoperative pain. Numerous studies have shown a decrease in pain score, even with immediate postoperative activity, which is significant for early post-op ambulation and regaining functionality sooner. However, studies have been in conclusive in patients undergoing lower extremity orthopedic surgery. For this reason, we hoped to study the effect of gabapentin on postoperative pain in patients undergoing total knee arthroplasty, total hip arthroplasty, or a hip fracture repair. This was done in the setting of ensuring adequate postoperative analgesia with regional blocks and opioid PCA, as is protocol at our institution. Given the sedative effects of gabapentin and the potential for improving postoperative sleep patterns, we also studied the drug's effect on this aspect of our patient's postoperative course. We utilized the Pittsburg Sleep Quality Index and Visual Analog Scale for pain to obtain a more objective standardized score amongst our study population. Our results indicate that gabapentin does not offer any additional relief in pain or improve sleep habits in patients who have received either a femoral or lumbar plexus block for lower extremity orthopedic surgery. This trial is registered with NCT01546857.

Combination of gabapentin and celecoxib for analgesia after major orthopedic surgery: a randomized, controlled trial

Background: The use of analgesics with different mechanism of action enhances post-operative pain relief by opioids. Both celecoxib and gabapentin have opioid-sparing effect, but it is unclear whether combination of the two drugs accentuates postoperative analgesia and further reduced opioid requirement.

Objective: Determine whether the perioperative use of celecoxib in combination with gabapentin reduces the amount of post-operative opioid consumption in comparison to celecoxib alone or gabapentin alone in patients that have major orthopedic surgery.

Materials and methods: Randomized double-blinded placebo controlled trial was done in 99 patients underwent major orthopedic surgery. They were randomly allocated into four groups. One to two hours before anesthesia, they received midazolam 7.5 mg plus study drugs. Group P received placebo plus placebo at 12 and 24 hours later. Group C received celecoxib 400 mg plus celecoxib 200 mg at 12 and 24 hour later. Group G received gabapentin 400 mg plus gabapentin 300 mg at 12 and 24 hour later. Finally, group CG received celecoxib 400 mg + gabapentin 400 mg plus celecoxib 200 mg + gabapentin 300 mg at 12 and 24 hour later. The patients underwent surgery under general anesthesia. Post-operative pain was treated by intravenous morphine patient-controlled analgesia.

Results: Median morphine consumption (minimum-maximum) in twenty-four hours was 18.0, 15.0, 15.5, and 8.0 mg, in group P, C, G, and CG, respectively. The group CG significantly consumed less morphine (41%) in 24 hour than group G, but not significantly less (38%) than group C. Pain score, sedation score, and nausea/vomiting at postoperative hour 1, 4, 8, 12, 16, 20, and 24 was not significantly different.

Conclusion: Combination of celecoxib and gabapentin further accentuated post-operative analgesia by morphine comparing to celecoxib or gabapentin alone without change in pain score and other side effects of the medications.

Gabapentin for post-operative pain management - a systematic review with meta-analyses and trial sequential analyses

BACKGROUND

Perioperative pain treatment often consist of combinations of non-opioid and opioid analgesics, 'multimodal analgesia', in which gabapentin is currently used. The aim was to document beneficial and harmful effects of perioperative gabapentin treatment.

METHODS

Randomized clinical trials comparing gabapentin vs. placebo or active placebo in adult surgical patients receiving gabapentin perioperatively were included. This review was conducted using Cochrane standards, trial sequential analysis (TSA), and Grading of Recommendations Assessment, Development, and Evaluation (GRADE). The primary outcomes were 24-h opioid consumption and incidence of serious adverse events (SAE).

RESULTS

One hundred and thirty-two trials with 9498 patients were included. Thirteen trials with low risk of bias reported a reduction in 24-h opioid consumption of 3.1 mg [0.5, 5.6] [corrected]. In the analysis of gabapentin as add-on analgesic to another non-opioid analgesic regimen found a mean reduction in 24-h morphine consumption of 1.2 mg [-0.3, 2.6; TSA-adjusted CI: -0.3, 2.6] in trials with low risk of bias. [corrected]. Nine trials with low risk of bias reported a risk ratio of SAEs of 1.61 [0.91; 2.86; TSA-adjusted CI: 0.57, 4.57].

CONCLUSION

Based on GRADE assessment of the primary outcomes in trials with low risk of bias, the results are low or very low quality of evidence due to imprecision, inconsistency, and in some outcomes indirectness. Firm evidence for use of gabapentin is lacking as clinically relevant beneficial effect of gabapentin may be absent and harm is imminent, especially when added to multimodal analgesia.

Adverse event assessment and reporting in trials of newer treatments for post-operative pain

BACKGROUND

Assessment and reporting of adverse events (AEs) in studies of perioperative interventions is critical given the potential for unintended and preventable iatrogenic morbidity and mortality. This focused review evaluated the quality of AE assessment and reporting in acute post-operative pain treatment trials. Since older analgesics (e.g., opioids, NSAIDs) already have a well-characterized safety profile, we concentrated on trials of pregabalin and gabapentin as a representative sample of studies where the perioperative safety profile was relatively unknown.

METHODS

We reviewed primary reports of trials of pregabalin and gabapentin for treatment of acute post-operative pain for: (1) adherence to the 10 recommendations from the 'CONSORT Extension for Harms,' (2) AE assessment method, (3) timing of AE assessment and reporting, and (4) assessment and reporting of AE severity.

RESULTS

We identified 31 trials of pregabalin and 59 of gabapentin. The median number of CONSORT harms recommendations that were satisfied was 7 of 10. The most common (41%) method of AE assessment was direct questioning about specific AEs by investigators. However, AE assessment method was not described in 18% of trials. AE assessments were reported for specified perioperative time points in only 24% of trials. Of greatest concern, no AE data were reported whatsoever in 8 of the included publications.

CONCLUSIONS

Considerable widespread improvements are needed in AE reporting for post-operative pain treatment trials. In addition to heightened awareness among clinical investigators, mandatory journal editorial policies may further facilitate improvements in safety assessment and reporting.

The Effect of Preoperative Gabapentin on Postoperative Nausea and Vomiting: A Meta-Analysis

BACKGROUND

Preoperative gabapentin has been shown to improve postoperative pain and limit reliance on opioid analgesia. On the basis of an alternative mechanism, our group investigated the ability of preoperative gabapentin to prevent postoperative nausea and vomiting (PONV).

METHODS

We performed a meta-analysis of trials that reported outcomes on the effect of preoperative gabapentin on PONV end points in patients undergoing general anesthesia. In our primary analysis, we calculated the pooled antiemetic effects of preoperative gabapentin in studies with PONV as the primary end point. In our secondary analysis, we calculated the pooled effects in trials involving preoperative gabapentin that reported on the side effects, nausea and vomiting.

RESULTS

Among the trials designed with PONV as a primary end point (8 trials; n = 838), preoperative gabapentin was associated with a significant reduction in PONV (risk ratio [RR] = 0.60; 99% confidence interval [CI], 0.50-0.72; P < 0.0001), nausea (RR = 0.34; 99% CI, 0.20-0.56; P < 0.0001), and vomiting (RR = 0.34; 99% CI, 0.19-0.61; P = 0.0002) at 24 hours. Among all included trials (44 trials; n = 3489) that reported on the side effects, nausea and vomiting, similar reductions were noted in PONV with preoperative gabapentin administration. Subgroup analysis of trials excluding repeat dosing, thiopental induction, and nitrous oxide maintenance and including high-risk surgery resulted in similar PONV efficacy. Preoperative gabapentin is also associated with significantly increased rates of postoperative sedation (RR = 1.22; 95% CI, 1.02-1.47; P = 0.03) compared with control.

CONCLUSIONS

Preoperative gabapentin is associated with a significant reduction in PONV among studies designed to investigate this end point. Preoperative gabapentin should be considered not only as part of a multimodal approach to postoperative analgesia, but also for prevention of PONV.

Opioid-sparing effect of selective cyclooxygenase-2 inhibitors on surgical outcomes after open colorectal surgery within an enhanced recovery after surgery protocol

AIM: To evaluate the opioid-sparing effect of selective cyclooxygenase-2 (COX-2) inhibitors on short-term surgical outcomes after open colorectal surgery.

METHODS: Patients undergoing open colorectal resection within an enhanced recovery after surgery protocol from 2011 to 2015 were reviewed. Patients with combined general anesthesia and epidural anesthesia, and those with acute colonic obstruction or perforation were excluded. Patients receiving selective COX-2 inhibitor were compared with well-matched individuals without such a drug. Outcome measures included numeric pain score and morphine milligram equivalent (MME) consumption on postoperative day (POD) 1-3, gastrointestinal recovery (time to tolerate solid diet and time to defecate), complications and length of postoperative stay.

RESULTS: There were 75 patients in each group. Pain score on POD 1-3 was not significantly different between two groups. However, MME consumption and MME consumption per kilogram body weight on POD 1-3 was significantly less in patients receiving a selective COX-2 inhibitor (P < 0.001). Median MME consumption per kilogram body weight on POD 1-3 was 0.09, 0.06 and nil, respectively in patients receiving a selective COX-2 inhibitor and 0.22, 0.25 and 0.07, respectively in the comparative group (P < 0.001), representing at least 59% opioid reduction. Patients prescribing a selective COX-2 inhibitor had a shorter median time to resumption of solid diet [1 (IQR 1-2) d vs 2 (IQR 2-3) d; P < 0.001] and time to first defecation [2 (IQR 2-3) d vs 3 (IQR 3-4) d; P < 0.001]. There was no significant difference in overall postoperative complications between two groups. However, median postoperative stay was significantly 1-d shorter in patients prescribing a selective COX-2 inhibitor [4 (IQR 3-5) d vs 5 (IQR 4-6) d; P < 0.001].

CONCLUSION: Perioperative administration of oral selective COX-2 inhibitors significantly decreased intravenous opioid consumption, shortened time to gastrointestinal recovery and reduced hospital stay after open colorectal surgery.

Multi-Modal Preemptive Analgesia With Pregabalin, Acetaminophen, Naproxen, and Dextromethorphan in Radical Neck Dissection Surgery: A Randomized Clinical Trial

Background

Preemptive analgesia may be considered as a method not only to alleviate postoperative pain but also to decrease analgesic consumption. Different regimens are suggested, but there is currently no standard.

Objectives

The aim was to measure the efficacy of preemptive analgesia with pregabalin, acetaminophen, naproxen, and dextromethorphan in radical neck dissection surgery for reducing the intensity of pain and morphine consumption.

Patients and Methods

This study was conducted as a randomized double-blind clinical trial. Eighty adult patients (18 to 60 years of age) under the American society of anesthesiologists (ASA) physical status I and II undergoing elective radical neck dissection were enrolled. Patients were randomized into two groups of 40 with a simple randomization method. The case group received a combination of 15 mg/kg acetaminophen, 2.5 mg/kg pregabalin, 7 mg/kg naproxen, and 0.3 mg/kg dextromethorphan administered orally one hour prior to surgery. Postoperative pain was assessed with the universal pain assessment tool (UPAT) at 0, 2, 4, 6, 12, and 24 hours after surgery. Subjects received morphine based on postoperative pain control protocol. Total administered morphine doses were noted.

Results

Postoperative pain rates at 0, 2, 4, 6, 12, and 24 hours after surgery were significantly lower for the case group than the control group (P values = 0.014, 0.003, 0.00, 0.00, and 0.00, respectively). Total morphine doses for the preemptive analgesia group were 45% lower than those of the other group. Side effects were similar for both groups.

Conclusions

A single preoperative oral dose of pregabalin, acetaminophen, dextromethorphan, and naproxen one hour before surgery is an effective method for reducing postoperative pain and morphine consumption in patients undergoing radical neck dissection.

Three -Agent Preemptive Analgesia, Pregabalin-Acetaminophen-Naproxen, in Laparotomy for Cancer: A Randomized Clinical Trial

Background

Pain management after abdominal surgery is a critical issue in cancer patients undergoing laparotomy. Opioid analgesics commonly used postoperatively have significant side effects and can postpone restoring normal life. Administration of analgesics before the surgery by inhibiting pain cascades may be an effective method for more efficient pain control.

Objectives

This study aimed to investigate the effect of the preemptive use of oral pregabalin-acetaminophen-naproxen on pain control and morphine consumptions in cancer patients undergoing laparotomy.

Patients and Methods

A total of 40 cancer patients scheduled for open abdominal surgery were randomized into the two groups. one group received combination of pregabalin 150 mg, acetaminophen 1 g and naproxen 250 mg (the PAN group) an hour before laparotomy. Following the surgery, morphine was administered on a protocolized schedule based on patients’ demand for pain control. Postoperative pain level was assessed using universal pain assessment tool (UPAT) at 0, 2, 4, 6, 12, 24 and 48 hours after the operation. The postoperative morphine dose and complications were noted. Data were analyzed using SPSS version 16.

Results

Patients in the PAN group had significantly lower UPAT scores at 0, 2, 4, 6, 12, 24 and 48 hours after the surgery than those in the control group (P = 0.008, 0.021, 0.008, 0.047, 0.004, 0.001, and 0.001). The mean dose of postoperative morphine consumption in the PAN group was 37% less than the control group (P = 0.001). The complications were not significantly different between the two groups.

Conclusions

Preemptive use of pregabalin-acetaminophen-naproxen decreases intensity of pain and morphine consumption in the cancer patients after laparotomy without significant complications.

Preoperative Gabapentin to Prevent Postoperative Shoulder Pain After Laparoscopic Ovarian Cystectomy: A Randomized Clinical Trial

BACKGROUND

Patients undergoing gynecology laparoscopy frequently experience shoulder pain as a common postoperative complication. Considering diaphragm stimulation in its pathophysiology, there are some advice to prevent or control this special form of referral pain.

OBJECTIVES

The current study aimed to assess the prophylactic effect of preoperative administration of oral gabapentin to prevent Post Laparoscopic Shoulder Pain (PLSP) after laparoscopic ovarian cystectomy.

PATIENTS AND METHODS

In a randomized, double blind, placebo controlled trial 40 female patients who were candidates to have elective laparoscopic ovarian cystectomy, received uniformed capsules containing gabapentin 600 mg or placebo 30 minutes before anesthesia induction. All patients had the American Society of Anesthesiologists (ASA) Physical Status of I-II and none had pervious abdominal surgery. Thereafter, the presence of side effects and PLSP and its severity was assessed by Visual Analog Scale (VAS) in the beginning of surgery and 2, 6, 12 hours after the surgery.

RESULTS

Comparing the gabapentin (n = 20) and placebo (n = 20) groups, basic characteristics including age (P = 0.446), Body Mass Index (BMI) (P = 0.876), pregnancy history (P = 0.660), and surgery time (P = 0.232) were statistically similar. PLSP occurrence was less frequent in the gabapentin group (45%) compared with the placebo group (75%) (P = 0.053), while In gabapentin group the VAS scores were lower in 2(P = 0.004), 6 (P = 0.132), and 12 (P = 0.036) hours, post operatively.

CONCLUSIONS

Prophylactic gabapentin administration could be considered as an effective and safe intervention to reduce occurrence and severity of PLSP after gynecologic laparoscopic cystectomy.

Gabapentin as an adjuvant for postoperative pain management in dogs undergoing mastectomy

This study aimed to evaluate the analgesic efficacy of gabapentin as an adjuvant for postoperative pain management in dogs. Twenty dogs undergoing mastectomy were randomized to receive perioperative oral placebo or gabapentin (10 mg/kg). All dogs were premedicated with intramuscular acepromazine (0.03 mg/kg) and morphine (0.3 mg/ kg). Anesthesia was induced with propofol (4 mg/kg) intravenously and maintained with isoflurane. Intravenous meloxicam (0.2 mg/kg) was administered preoperatively. Postoperative analgesia was evaluated for 72 hr. Rescue analgesia was provided with intramuscular morphine (0.5 mg/kg). Dogs in the Placebo group received significantly more morphine doses than the Gabapentin group (P=0.021), despite no significant differences in pain scores. Perioperative gabapentin reduced the postoperative morphine requirements in dogs after mastectomy.

Development and characterization of a novel, anatomically relevant rat model of acute postoperative pain

Acute postoperative pain remains a significant health care issue. Development of anatomically relevant animal models of postoperative pain, with improved predictive validity, would advance understanding of postoperative pain mechanisms and improve treatment outcomes. This study aimed to develop, characterize, and validate a rat model of acute postoperative pain associated with inguinal hernia repair based on the Lichtenstein inguinal hernia repair procedure (without hernia induction). We hypothesized that the surgery would result in reduced spontaneous locomotor activity, which would represent a pain-related phenotype. Postsurgical characterization involved extensive monitoring of home cage and open field locomotor activity, as well as mechanical hypersensitivity and assessment of c-Fos expression in the dorsal horn of the spinal cord. In pharmacologic validation studies, rats received morphine, carprofen, or paracetamol 1 hour before, and/or immediately after, surgery. Rats that underwent hernia repair surgery exhibited significantly lower horizontal and vertical activities in the home cage and open field in the early postsurgical period, compared with sham rats or rats that underwent skin incision only. Morphine, carprofen, and paracetamol attenuated the surgery-induced reductions in locomotor activity, to varying degrees. Surgery was associated with significantly increased c-Fos expression in the ipsilateral dorsal horn of the spinal cord, an effect attenuated by carprofen treatment. These results support the development and characterization of a novel, anatomically relevant animal model of acute postoperative pain that may facilitate development of improved treatment regimens.

PERSPECTIVE

Acute pain following inguinal hernia repair can be difficult to treat. Here we report, for the first time, the development of a novel, anatomically relevant rat model to facilitate improved understanding and treatment of acute postoperative pain following inguinal hernia repair.

Analgesic effects of gabapentin after scoliosis surgery in children: a randomized controlled trial

BACKGROUND

Postoperative pain remains an important challenge after scoliosis surgery in children. Opioids are the mainstay of treatment, and adult studies demonstrate gabapentin as a useful adjunct to opioids in the management of postoperative pain.

METHOD

Adolescent patients undergoing idiopathic scoliosis surgery were randomized to receive a single preoperative dose of gabapentin 600 mg or placebo. The primary outcome measure was total morphine consumption in mg·kg(-1) between 0 and 24 h postoperatively. Secondary outcome measures included time to first rescue analgesia, pain intensity scores at rest and with movement, incidence of nausea, vomiting, pruritus, sedation, dizziness, presence of persisting pain symptoms, and patient satisfaction. Cumulative opioid consumption was calculated at each time point: 1, 4, 8, 12, 24, 48, and 72 h.

RESULTS

The gabapentin group used 0.087 ± 0.06 mg·kg(-1) of morphine at 1 h, 0.24 ± 0.12 mg·kg(-1) at 4 h, 0.44 ± 0.17 mg·kg(-1) at 8 h, and 1.29 ± 0.44 mg·kg(-1) at 24 h. The placebo group used 0.121 ± 0.06 mg·kg(-1) of morphine at 1 h, 0.35 ± 0.16 mg·kg(-1) at 4 h, 0.56 ± 0.27 mg·kg(-1) at 8 h, and 1.46 ± 0.68 mg·kg(-1) at 24 h. There was no statistically significant reduction in opioid consumption in the patients receiving gabapentin. There were no significant differences in secondary outcomes.

CONCLUSION

A single preoperative dose of gabapentin did not show a significant difference in opioid consumption or pain scores in adolescents undergoing idiopathic scoliosis surgery. This study is the first pediatric randomized controlled trial to assess the effectiveness of a single dose of gabapentin on morphine consumption and analgesia following major surgery.