Preventing Persistent Postsurgical Pain: A Systematic Review and Component Network Meta-analysis

Preoperative Gabapentin for Pain Control: A Randomized, Placebo-controlled Clinical Trial in Patients Undergoing Inguinal Hernioplasty

PURPOSE

The perioperative use of gabapentin has been suggested to reduce postoperative pain and opioid consumption. However, there is a variation in clinical practice, the type of surgery and the administration time seem to be distinct between the available studies. We assess whether gabapentin administered before surgery reduces postoperative pain in patients who have undergone inguinal hernioplasty.

DESIGN

This is a double-blind, randomized, and placebo-controlled trial.

METHODS

Seventy-seven patients scheduled for inguinal hernioplasty were randomized in two groups to receive gabapentin (900 mg) or placebo in the perioperative period. The primary outcome was analgesia measured by visual analog scale up to 30 days after surgery. The secondary outcomes such as morphine consumption, nausea, headache, and sedation have been also described.

FINDINGS

Patients who received gabapentin had lower postoperative pain scores compared to the control group, P < .001. The postoperative morphine use was significantly lower in the gabapentin (5.3%) versus placebo group (74.4%), P < .001. No significant difference between groups was observed for the occurrence of adverse events.

CONCLUSIONS

The perioperative administration of gabapentin was effective in reducing postoperative pain and had an important effect in decreasing morphine use. Together, our data reveal a long-lasting opioid-sparing effect of gabapentin in patients who underwent inguinal hernioplasty.

Mechanisms and Preventative Strategies for Persistent Pain following Knee and Hip Joint Replacement Surgery: A Narrative Review

Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.

Efficacy and safety of perioperative ketamine for the prevention of chronic postsurgical pain: A meta-analysis

STUDY OBJECTIVE

Assessment of the efficacy and safety of perioperative intravenous ketamine in reducing incidence and severity of chronic postsurgical pain.

STUDY DESIGN

A systematic review and meta-analysis of randomized controlled trials (RCTs).

DATA SOURCES

The following data sources were systematically searched: MEDLINE, CENTRAL, and EMBASE (till 02/2021).

PATIENTS

Adult patients undergoing any surgery.

INTERVENTIONS

Perioperative use of intravenous ketamine as an additive analgesic drug compared to placebo, no active control treatment, and other additive drugs.

MEASUREMENTS

Primary outcomes were number of patients with chronic postsurgical pain after 6 months and ketamine related adverse effects. Secondary outcomes were chronic postsurgical pain incidence after 3 and 12 months, chronic postsurgical neuropathic pain incidence, chronic postsurgical moderate to severe pain incidence, intensity of chronic postsurgical pain at rest, and during movement, oral morphine consumption after 3, 6, and 12 months and incidence of opioid-related adverse effects.

MAIN RESULTS

Thirty-six RCTs were included with a total of 3572 patients. Ketamine compared to placebo may result in no difference in the number of patients with chronic postsurgical pain after 6 months (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.71-1.05; I2  = 34%; 16 studies; low-certainty evidence). Ketamine may reduce the incidence of chronic postsurgical neuropathic pain after 3 months in comparison to placebo (RR 0.78, 95% CI 0.62-0.99, I2  = 31%, seven trials, low-certainty evidence). Ketamine compared to placebo may increase the risk for postoperative nystagmus (RR 9.04, 95% CI 1.15-70.90, I2 30%, two trials, low-certainty evidence) and postoperative visual disturbances (RR 2.29, 95% CI 1.05-4.99, I2 10%, seven trials, low-certainty evidence).

CONCLUSIONS

There is low-certainty evidence that perioperative ketamine has no effect on chronic postsurgical pain in adult patients. Low-certainty evidence suggests that ketamine compared to placebo may reduce incidence of chronic postsurgical neuropathic pain after 3 months. Questions like ideal dosing, treatment duration and more patient-related outcome measures remain unanswered, which warrants further studies.

PROTOCOL REGISTRATION

Prospero CRD42021223625, 07.01.2021.

Personalized medicine: Somatosensory phenotyping in musculoskeletal pain conditions

BACKGROUND

Current clinical phenotyping of musculoskeletal pain provides very limited evidence- based support to personalized medicine. This paper discusses the potential of somatosensory phenotyping to contribute to personalized medicine for prognosis and prediction of treatment effects.

METHODS

Highlight of definitions and regulatory requirements for phenotypes and biomarkers. Appraisal of the literature on somatosensory phenotyping in musculoskeletal pain.

RESULTS

Somatosensory phenotyping can identify clinical conditions and manifestations that may affect treatment decisions. However, studies have shown inconsistent associations of phenotyping measures with clinical outcomes, and the strength of association is mostly weak. Most somatosensory measures have been developed for research, are too demanding to find large acceptance in clinical settings, and have uncertain clinical usefulness.

CONCLUSIONS

Current somatosensory measures will unlikely be validated as strong prognostic or predictive biomarkers. However, they still have the potential to support personalized medicine. Including somatosensory measures in biomarker signatures, that is, a set of measures that are collectively associated with outcomes, is potentially more useful than aiming to the identification of single biomarkers. Furthermore, somatosensory phenotyping may be introduced as part of patient's evaluation to contribute to better-informed and personalized treatment decisions. To this purpose, a change in the way research currently approaches somatosensory phenotyping is warranted. A pathway is proposed that involves: (1) the identification of clinically applicable measures that are specific to clinical conditions; (2) the association of somatosensory phenotypes with outcomes; (3) multi-site replication; and (4) the determination of clinical benefits in randomized controlled trials.

SIGNIFICANCE

Somatosensory phenotyping has the potential to support personalized medicine. However, current measures do not seem to meet the criteria for being strong prognostic or predictive biomarkers, most of them are too demanding to find large acceptance in clinical settings, and their clinical usefulness has not been proven. The value of somatosensory phenotyping can be more realistically determined by re-orienting research to the development of simplified testing protocols, applicable to large-scale clinical practice, and tested for clinical usefulness in randomized controlled trials.

Benefits versus harm of intraoperative glucocorticoid for postoperative nausea and vomiting prophylaxis

Intraoperative use of glucocorticoids is effective for postoperative nausea and vomiting prophylaxis and can also provide early postoperative analgesic effects, but the consequences for chronic post-surgical pain are debatable. In a secondary analysis of the large pragmatic Perioperative Administration of Dexamethasone and Infection trial (n=8478), the primary outcome of pain at the surgical wound at 6 months after surgery was increased in subjects receiving dexamethasone 8 mg i.v. for postoperative nausea and vomiting prophylaxis, a dose not associated with the detrimental effect of surgical site infection in the original study. In contrast, a more detailed assessment of chronic post-surgical pain after exclusion of patients with preoperative pain at the surgical site showed no differences with or without intraoperative dexamethasone regarding chronic post-surgical pain characteristics (intensity and neuropathic features). Because of several confounding factors especially regarding surgical details, these unexpected findings call for more well-designed studies about the potential risk of intraoperative treatments, such as glucocorticoids, on late post-surgical pain.

Nurses' Assessments Versus Patients' Self-Assessments of Postoperative Pain: Knowledge and Skills of Nurses for Effective Pain Management

Postoperative pain is the most common form of acute pain. Nurses contribute to effective pain management with their knowledge and skills. The aims of this research were to examine differences between nurses' assessments and patients' self-assessments of postoperative pain, differences in the mentioned (self) assessments with respect to characteristics of both groups of respondents, and the correlation between the NRS and the VRS scale. The study included 103 nurses employed at a hospital and 103 patients treated in the surgical departments after the surgical procedures. Data were collected using the standardized Numerical rating scale (NRS) and Verbal rating score (VRS). The median of patients' self-assessments of pain intensity on the NRS scale was 4, while the nursing assessment of patients' pain was 3, with no significant difference (p = 0.083). No significant differences were found on the VRS scale between nurse assessments and patient self-assessments of current pain intensity. The pain was described as moderate by 35% of participants, including 35.9% nurses and 35% patients. Significant positive correlations were recorded between values on the VRS and NRS scales for nurses (Rho = 0.812; p < 0.001) and patients (Rho = 0.830; p < 0.001). The results of this study may have implications for the improvement of postoperative pain management protocols, with regular use of pain assessment scales and individualization of analgesic prescriptions.

Non-opioid analgesics for the prevention of chronic postsurgical pain: a systematic review and network meta-analysis

BACKGROUND

Chronic postsurgical pain is common after surgery. Identification of non-opioid analgesics with potential for preventing chronic postsurgical pain is important, although trials are often underpowered. Network meta-analysis offers an opportunity to improve power and to identify the most promising therapy for clinical use and future studies.

METHODS

We conducted a PRISMA-NMA-compliant systematic review and network meta-analysis of randomised controlled trials of non-opioid analgesics for chronic postsurgical pain. Outcomes included incidence and severity of chronic postsurgical pain, serious adverse events, and chronic opioid use.

RESULTS

We included 132 randomised controlled trials with 23 902 participants. In order of efficacy, i.v. lidocaine (odds ratio [OR] 0.32; 95% credible interval [CrI] 0.17-0.58), ketamine (OR 0.64; 95% CrI 0.44-0.92), gabapentinoids (OR 0.67; 95% CrI 0.47-0.92), and possibly dexmedetomidine (OR 0.36; 95% CrI 0.12-1.00) reduced the incidence of chronic postsurgical pain at ≤6 months. There was little available evidence for chronic postsurgical pain at >6 months, combinations agents, chronic opioid use, and serious adverse events. Variable baseline risk was identified as a potential violation to the network meta-analysis transitivity assumption, so results are reported from a fixed value of this, with analgesics more effective at higher baseline risk. The confidence in these findings was low because of problems with risk of bias and imprecision.

CONCLUSIONS

Lidocaine (most effective), ketamine, and gabapentinoids could be effective in reducing chronic postsurgical pain ≤6 months although confidence is low. Moreover, variable baseline risk might violate transitivity in network meta-analysis of analgesics; this recommends use of our methods in future network meta-analyses.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42021269642.