Prevention of Post-Mastectomy Pain Syndrome: A Review of Recent Literature on Perioperative Interventions

PURPOSE OF REVIEW

Up to 60% of breast cancer patients continue to experience pain three months or more after surgery, with 15 to 25% reporting moderate to severe pain. Post-mastectomy pain syndrome (PMPS) places a high burden on patients. We reviewed recent studies on perioperative interventions to prevent PMPS incidence and severity.

RECENT FINDINGS

Recent studies on pharmacologic and regional anesthetic interventions were reviewed. Only nine of the twenty-three studies included reported a significant improvement in PMPS incidence and/or severity, sometimes with mixed results for similar interventions. Evidence for prevention of PMPS is mixed. Further investigation of impact of variations in dosing is warranted. In addition, promising newer interventions for prevention of PMPS such as cryoneurolysis of intercostal nerves and stellate ganglion block need confirmatory studies.

Prevention of persistent pain with lidocaine infusions in breast cancer surgery (PLAN): study protocol for a multicenter randomized controlled trial

BACKGROUND

Persistent pain is a common yet debilitating complication after breast cancer surgery. Given the pervasive effects of this pain disorder on the patient and healthcare system, post-mastectomy pain syndrome (PMPS) is becoming a larger population health problem, especially as the prognosis and survivorship of breast cancer increases. Interventions that prevent persistent pain after breast surgery are needed to improve the quality of life of breast cancer survivors. An intraoperative intravenous lidocaine infusion has emerged as a potential intervention to decrease the incidence of PMPS. We aim to determine the definitive effects of this intervention in patients undergoing breast cancer surgery.

METHODS

PLAN will be a multicenter, parallel-group, blinded, 1:1 randomized, placebo-controlled trial of 1,602 patients undergoing breast cancer surgery. Adult patients scheduled for a lumpectomy or mastectomy will be randomized to receive an intravenous 2% lidocaine bolus of 1.5 mg/kg with induction of anesthesia, followed by a 2.0 mg/kg/h infusion until the end of surgery, or placebo solution (normal saline) at the same volume. The primary outcome will be the incidence of persistent pain at 3 months. Secondary outcomes include the incidence of pain and opioid consumption at 1 h, 1-3 days, and 12 months after surgery, as well as emotional, physical, and functional parameters, and cost-effectiveness.

DISCUSSION

This trial aims to provide definitive evidence on an intervention that could potentially prevent persistent pain after breast cancer surgery. If this trial is successful, lidocaine infusion would be integrated as standard of care in breast cancer management. This inexpensive, widely available, and easily administered intervention has the potential to reduce pain and suffering in an already afflicted patient population, decrease the substantial costs of chronic pain management, potentially decrease opioid use, and improve the quality of life in patients.

TRIAL REGISTRATION

This trial has been registered on clinicaltrials.gov (NCT04874038, Dr. James Khan. Date of registration: May 5, 2021).

The analgesic effectiveness of perioperative lidocaine infusions for acute and chronic persistent postsurgical pain in patients undergoing breast cancer surgery: a systematic review and meta-analysis

BACKGROUND

Breast cancer is the most common cancer among women and tumour resection carries a high prevalence of chronic persistent postsurgical pain (CPSP). Perioperative i.v. lidocaine infusion has been proposed as protective against CPSP; however, evidence of its benefits is conflicting. This review evaluates the effectiveness of perioperative lidocaine infusions for breast cancer surgery.

METHODS

Randomised trials comparing perioperative lidocaine infusions with parenteral analgesia in breast cancer surgery patients were sought. The two co-primary outcomes were the odds of CPSP at 3 and 6 months after operation. Secondary outcomes included rest pain at 1, 6, 12, and 24 h; analgesic consumption at 0-24 and 25-48 h; quality of recovery; opioid-related side-effects; and lidocaine infusion side-effects. Hartung-Knapp-Sidik-Jonkman (HKSJ) random effects modelling was used.

RESULTS

Thirteen trials (1039 patients; lidocaine: 518, control: 521) were included. Compared with control, perioperative lidocaine infusion did not decrease the odds of developing CPSP at 3 and 6 months. Lidocaine infusion improved postoperative pain at 1 h by a mean difference (95% confidence interval) of -0.65 cm (-0.73 to -0.57 cm) (P<0.0001); however, this difference was not clinically important (1.1 cm threshold). Similarly, lidocaine infusion reduced oral morphine consumption by 7.06 mg (-13.19 to -0.93) (P=0.029) over the first 24 h only; however, this difference was not clinically important (30 mg threshold). The groups were not different for any of the remaining outcomes.

CONCLUSIONS

Our results provide moderate-quality evidence that perioperative lidocaine infusion does not reduce CPSP in patients undergoing breast cancer surgery. Routine use of lidocaine infusions for perioperative analgesia and CPSP prevention is not supported in this population.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42023420888.

Opioid-free anesthesia: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate all available evidence thus far on opioid based versus opioid-free anesthesia and its effect on acute and chronic postoperative pain.

DESIGN

Systematic review and meta-analysis of randomized clinical trials.

SETTING

Operating room, postoperative recovery room and ward.

PATIENTS

Patients undergoing general anesthesia.

INTERVENTIONS

After consulting MEDLINE, EMBASE and Cochrane database, studies which compared opioid free anesthesia (OFA) with opioid based anesthesia (OBA) were included (last search April 15th 2022).

MEASUREMENTS

Primary outcomes were acute and chronic pain scores in NRS or VAS. Secondary outcomes were quality of recovery and postoperative opioid consumption. Risk of bias was assessed using the RoB2 tool and a random effects model for the meta-analysis was conducted.

MAIN RESULTS

We identified 1245 citations, of which 38 studies met our inclusion criteria. There is moderate quality evidence showing no clinically relevant difference of Numeric Rating Scale (NRS) scores or opioid consumption in the postoperative period (pooled mean difference of 0.39 points with a CI of 0.19-0.59 and 4.02 MME with a CI of 1.73-6.30). We found only one small-sized study reporting no effect of opioid-free anesthesia on chronic pain. The quality of recovery was superior in patients with opioid-free anesthesia (mean difference of 8.26 points), however, this pooled analysis was comprised of only two studies. Postoperative nausea and vomiting (PONV) occurred less in opioid-free anesthesia, but bradycardia was more frequent.

CONCLUSIONS

We concluded that we cannot recommend one strategy over the other. Future studies could focus on quality of recovery as outcome measure and adequately powered studies on the effects of opioid-free anesthesia on chronic pain are eagerly awaited.

Non-Surgical Site Pain in Women following Breast Cancer Surgery: A Systematic Review and Meta-Analysis

Background

Chronic pain after breast cancer surgery affects up to 60% of patients. Evidence supports the fact that pain outwith the surgical site is a significant issue. This systematic review and meta-analysis sought to evaluate the prevalence of non-surgical site pain (NSSP) in women after breast cancer surgery at 6 months post-operatively.

Methods

Adult women with a confirmed breast cancer diagnosis who had undergone breast cancer surgery were identified. The outcome pursued was pain outwith the surgical site measured on either NRS/VRS or VAS rating scale. CENTRAL, Embase, PubMed, MEDLINE, CINAHL, PsycInfo, Web of Science, and Scopus were searched to identify studies that examined NSSP after breast cancer surgery at 6 months. Data were gathered via pre-piloted Excel forms and analysed both quantitively and qualitatively. Meta-analysis was carried out using a random-effects model to assess risk difference with 95% confidence interval (CI).

Results

A total of sixteen studies were identified for inclusion. Eleven studies failed to provide sufficient data and consequently were analysed qualitatively. Five studies were adequate for quantitative analysis, including a total of 995 patients. Meta-analysis identified a risk difference of 18% (95% CI: 5-31%) between patients who had breast cancer surgery and a reference, however, this is low-quality evidence.

Conclusion

This review has highlighted that breast cancer surgery increases the risk of pain outwith the surgical site postoperatively. It was additionally identified that NSSP data are often gathered in research yet rarely presented in results or highlighted as a primary outcome. As the quality of evidence was low, research specifying NSSP as a primary outcome is required to provide more certainty.

Perioperative intravenous lidocaine for postoperative pain in patients undergoing breast surgery: a meta-analysis with trial sequential analysis of randomized controlled trials

Background

The effectiveness of intravenous lidocaine infusion in managing acute and chronic pain following breast surgery has been a topic of debate. This meta-analysis aims to assess the impact of perioperative intravenous lidocaine on the relief of postoperative pain among patients undergoing breast surgery.

Methods

A systematic search of databases was conducted to identify randomized controlled trials (RCTs) that compared the effects of intravenous lidocaine infusion with placebo or routine care in patients undergoing breast surgery. The primary outcome of interest was the occurrence of chronic post-surgical pain (CPSP) at the longest follow-up. Meta-analyses, incorporating trial sequential analysis, were performed using a random-effects model to assess the overall effect.

Results

A total of twelve trials, involving 879 patients, were included in the analysis. Perioperative intravenous lidocaine demonstrated a significant reduction in the incidence of CPSP at the longest follow-up (risk ratio [RR] 0.62, 95% confidence interval [CI] 0.48-0.81; P = 0.0005; I2 = 6%). Trial sequential analysis (TSA) indicated that the cumulative z curve crossed the trial sequential monitoring boundary for benefit, providing sufficient and conclusive evidence. Furthermore, intravenous lidocaine was associated with decreased opioid consumption and a shorter length of hospital stay.

Conclusion

Perioperative intravenous lidocaine is effective in relieving acute and CPSP in patients undergoing breast surgery.

Systematic review registration

https://inplasy.com/, identifier INPLASY2022100033.

Effect of intravenous lidocaine on pain after head and neck cancer surgery (ELICO trial): A randomised controlled trial

BACKGROUND

Treatment of postoperative pain after ear, nose and throat (ENT) cancer surgery is mainly morphine administration. Additional systemic lidocaine has shown promising results in some surgical procedures.

OBJECTIVE

The main objective was to evaluate morphine consumption in the first 48 postoperative hours after intra-operative lidocaine infusion during major ENT cancer surgery.

DESIGN

A randomised, double-blind, placebo-controlled trial.

SETTING

Bicentric study including a university hospital and a major cancer centre, conducted from December 2016 to December 2019.

PATIENTS

A total of 144 patients undergoing major ENT cancer surgery were included.

INTERVENTION

The patients were randomly assigned to receive intravenous lidocaine or placebo during surgery and in the recovery room.

MAIN OUTCOME MEASURES

Endpoints were postoperative morphine consumption in the first 24 and 48 h postoperatively, intra-operative remifentanil consumption, adverse events occurrence and assessment 3 to 6 months after surgery with the McGill pain questionnaire.

RESULTS

A total of 118 patients were included (lidocaine n  = 57; placebo n  = 61, 26 patients were excluded). There was no significant difference in morphine consumption during the first 48 postoperative hours in the lidocaine group compared with the placebo group with a median [IQR] of 0.60 [0.30 to 1.03] mg kg -1 vs. 0.57 [0.37 to 0.96] mg kg -1 , total dose 44 [21 to 73.3] mg vs. 38 [23.3 to 56.5] mg, P  = 0.92.There was no significant difference between the two groups in any of the other endpoints, including at follow up 3 to 6 months after surgery.

CONCLUSION

Intravenous lidocaine in ENT cancer surgery did not show any additional analgesic or morphine-sparing effect 48 h after surgery. Three to six months after surgery, there was no significant difference in pain scores or consumption of analgesics. Patients treated pre-operatively with opioids were not evaluated in the study.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02894710 and EUDRACT number 2015-005799-90.

Effect of lidocaine perioperative infusion on chronic postsurgical pain in patients undergoing thoracoscopic radical pneumonectomy

BACKGROUND

Thoracoscopic radical pneumonectomy is associated with a high incidence of postoperative chronic pain. Studies on the benefits of lidocaine intravenous infusion during the perioperative period were still controversial in thoracoscopic surgery.

METHODS

Sixty-four lung cancer patients scheduled for thoracoscopic radical pneumonectomy were randomly divided into two groups: normal saline group (control group) or lidocaine group. In the lidocaine group, 1.5 mg/kg lidocaine was administered during the anesthesia induction, and 2 mg·kg^-1·h^-1 lidocaine was continuously intravenous infused until the end of the surgery. After the surgery, a mixture of 2 μg/kg sufentanil and 10 mg/kg lidocaine was continuously intravenous infused by postoperative patient-controlled intravenous analgesia pump (100 ml). In the control group, the same volume of normal saline was administered according to the calculation of lidocaine during anesthesia induction, maintenance and postoperative patient-controlled intravenous analgesia. The primary outcome was the incidence of chronic postoperative pain at 3 months after the surgery. The secondary outcomes include the incidence of chronic postoperative pain at 6 months after the surgery; the effect of lidocaine on postoperative pain within the first 24 and 48 h; total amount of sufentanil administered during entire procedure and the number of PCA triggers within 48 h after surgery.

RESULTS

Compared with the control group, the incidence of chronic pain at 3 months after the surgery was significantly lower (13 cases, 46.4% vs. 6 cases, 20.7%, p < 0.05), but no significant difference at 6 months between two group. The cumulative dosage of sufentanil in perioperative period was significantly lower (149.64 ± 18.20 μg vs. 139.47 ± 16.75 μg) (p < 0.05), and the number of PCA triggers (8.21 ± 4.37 vs. 5.83 ± 4.12, p < 0.05) was significantly greater in the control group. The NRS pain scores at 24 h (1.68 ± 0.72 vs. 1.90 ± 0.86) and 48 h (1.21 ± 0.42 vs. 1.20 ± 0.41) after the operation were no significant difference.

CONCLUSION

Perioperative infusion lidocaine significantly reduced the number of PCA triggers and the incidence of chronic postoperative pain at 3 months after the thoracoscopic radical pneumonectomy.

TRIAL REGISTRATION

http://www.chictr.org.cn : ChiCTR1900024759, frist registration date 26/07/2019.

Influence of Deep Serratus Anterior Plane Block on Chronic Pain at 3 Months After Breast-Conserving Surgery: Prospective, Cohort Study

OBJECTIVES

In 2015, we evaluated our practices regarding pain after breast-conserving surgery. Thereafter, we have adapted our practices by performing a systematic deep serratus plane block before the surgical incision. In 2019, we assessed the impact of these changes in terms of chronic pain. The main objective of this study was to evaluate the prevalence of chronic pain 3 months after this type of surgery.

MATERIALS AND METHODS

All patients treated with breast-conserving surgery as outpatients were included in this prospective study between April and July 2019. After inducing general anesthesia, 20 mL of ropivacaine 3.75 mg/mL were injected under the serratus muscle. Morphine titration was performed in the recovery room according to pain scores. A pain and quality of life questionnaire was sent 3 months after surgery. A backward logistic regression model was applied to calculate the adjusted odds ratios.

RESULTS

The final analysis involved 137 patients. Three months after surgery, 43 patients (31%) reported persistent pain related to the surgery. Maximum pain in the last 24 hours was moderate to severe in 60% of cases, 16 patients (35%) took painkillers. Morphine titration in the recovery room was required in 25 patients (18%). Younger age and the use of lidocaine to prevent after injection of propofol during general anesthesia induction appeared to be protective factors for the risk of pain at 3 months (secondary endpoints).

DISCUSSION

No persistent pain at 3 months was reported in 69% of cases. Furthermore, the use of a deep serratus anterior plane block before the surgical incision has limited the need for morphine titration in the recovery room to <1 patient in 5. These evaluations of professional practices should be encouraged.

Individualized multidisciplinary analgesia to prevent persistent postsurgical pain

PURPOSE OF REVIEW

Persistent postsurgical pain as outcome of surgery has reached more attention in the past years. In the first place because of related disability, long-term use of (opioid)analgesics and impact on the quality of life of individual patients. In addition, the individual and societal socio-economic burden of PPSP is high and increasing in the light of increasing numbers of surgery world-wide.

RECENT FINDINGS

Actual studies identified risk factors for persistent postsurgical pain in relevant patient populations. Astonishingly, most of predicting factors seem unrelated to surgery.

SUMMARY

Future perioperative practice will have to focus on identifying patients at risk for PPSP before surgery and develop/offer suitable individually tailored preventive interventions.

Perioperative Breast Analgesia: a Systematic Review of the Evidence for Perioperative Analgesic Medications

PURPOSE OF REVIEW

Breast surgery is common and may result in significant acute as well as chronic pain. A wide range of pharmacologic interventions is available including opioids, non-steroidal anti-inflammatory drugs (NSAIDs), N-methyl-D-aspartate (NMDA) receptor antagonists, anticonvulsants, and other non-opioids with analgesic properties. We present a review of the evidence for these pharmacologic interventions. A literature search of the MEDLINE database was performed via PubMed with combined terms related to breast surgery, anesthesia, and analgesia. Articles were limited to randomized controlled trial (RCT) design, adult patients undergoing elective surgery on the breast (not including biopsy), and pharmacologic interventions only. Article titles and abstracts were screened, and risk of bias assessments were performed.

RECENT FINDINGS

The search strategy initially captured 7254 articles of which 60 articles met the full inclusion criteria. Articles were organized according to intervention: 6 opioid agonists, 14 NSAIDs and acetaminophen, 4 alpha-2 agonists, 7 NMDA receptor antagonists, 6 local anesthetics, 7 steroids, 15 anticonvulsants (one of which also discussed an NMDA antagonist), 1 antiarrhythmic, and 2 serotonin reuptake inhibitors (one of which also studied an anticonvulsant). A wide variety of medications is effective for perioperative breast analgesia, but results vary by agent and dose. The most efficacious are likely NSAIDs and anticonvulsants. Some agents may also decrease the incidence of chronic postoperative pain, including flurbiprofen, gabapentin, venlafaxine, and memantine. While many individual agents are well studied, optimal combinations of analgesic medications remain unclear.

Perioperative Dexmedetomidine or Lidocaine Infusion for the Prevention of Chronic Postoperative and Neuropathic Pain After Gynecological Surgery: A Randomized, Placebo-Controlled, Double-Blind Study

Introduction

The transition of acute to chronic postoperative pain (CPP) remains a significant burden to the rehabilitation of patients. The research for adjuvants to prevent CPP continues; among others, dexmedetomidine and lidocaine seem promising agents.

Methods

This is a long-term follow-up of a randomized, placebo-controlled, double-blind study on women who underwent open abdominal gynecological surgery and received dexmedetomidine or lidocaine or placebo infusion perioperatively (n = 81). The effect of these adjuvants on the development of CPP and neuropathic pain was assessed during a 12-month follow-up. Eighty-one (81) women ASA I–II, aged between 30 and 70 years, were randomly assigned to receive either dexmedetomidine (DEX group) or lidocaine (LIDO group) or placebo (CONTROL group) perioperatively. Before anesthesia induction, all patients received a loading intravenous dose of either 0.6 μg/kg dexmedetomidine or 1.5 mg/kg lidocaine or placebo, followed by 0.6 μg/kg/h dexmedetomidine or 1.5 mg/kg/h lidocaine or placebo until last suture. Patients were followed up to obtain the long-term outcomes at 3, 6, and 12 months. At these time-points, pain intensity was assessed with the Numerical Rating Scale, (NRS: 0–10) and the development of neuropathic elements with the Douleur Neuropathique 4 (DN4) score. Prognostic parameters that could affect chronic pain and its components were also identified.

Results

Data from 74 women were analyzed. Dexmedetomidine significantly reduced NRS scores comparing to placebo at 3 months (p = 0.018), while at 6 months, lidocaine was found superior to placebo (p = 0.02), but not to dexmedetomidine, in preventing neuropathic pain (DN4 < 4). Regarding secondary endpoints, higher NRS cough scores at 48 h were associated with statistically significant NRS and DN4 scores at 3, 6, and 12 months (p < 0.02). At 6 months, a statistically significant correlation was also found between higher NRS values and older age (p = 0.020).

Conclusions

Dexmedetomidine was superior to placebo regarding the duration and severity of CPP, while lidocaine exhibited a protective effect against neuropathic elements of CPP.

Trial registration

ClinicalTrials.gov identifier, NCT03363425.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-022-00361-5.

"Post Mastectomy Pain Syndrome: A Systematic Review of Prevention Modalities"

Background

Post-mastectomy pain syndrome (PMPS) is a surgical complication of breast surgery characterized by chronic neuropathic pain. The development of PMPS is multifactorial and research on its prevention is limited. The objective of this systematic review is to synthesize the existing evidence on interventions for lowering the incidence of persistent neuropathic pain after breast surgery.

Methods

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we performed a comprehensive search of the electronic databases of MEDLINE, Cochrane Library, Embase, CINAHL, PsycINFO, Web of Science, and ClinicalTrials.gov using a combination of database-specific controlled vocabulary and keyword searches. Two reviewers independently screened all unique records. Publications on chronic (>3-month duration) pain after breast cancer-related surgery were included. Studies were classified by modality.

Results

Our literature search yielded 7092 articles after deduplication. We identified 45 studies that met final inclusion criteria for analysis, including 37 randomized-controlled trials. These studies revealed seven major intervention modalities for prevention of PMPS: physical therapy, mindfulness-based cognitive therapy, oral medications, surgical intervention, anesthesia, nerve blocks, and topical medication therapy.

Conclusion

High-quality data on preventative techniques for PMPS are required to inform decisions for breast cancer survivors. We present a comprehensive assessment of the modalities available that can help guide breast and reconstructive surgeons employ effective strategies to lower the incidence and severity of PMPS. Our review supports the use of multimodal care involving both a peripherally targeted treatment and centrally acting medication to prevent the development of PMPS.

Association between perioperative intravenous lidocaine and subjective quality of recovery: A meta-analysis of randomized controlled trials

STUDY OBJECTIVE

To evaluate the impact of perioperative intravenous lidocaine on the quality of recovery (QoR) following surgery.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

SETTING

Postoperative care.

INTERVENTION

Intravenous lidocaine during perioperative period.

PATIENTS

Adults undergoing surgery under general anesthesia.

MEASUREMENTS

The primary outcome was postoperative QoR measured with QoR-40 questionnaire, while the secondary outcomes included five individual dimensions (i.e., emotional, state, physical comfort, psychological support, physical independence, and pain) of QoR-40, intraoperative opioid consumption, and risk of chronic postsurgical pain (CPSP).

MAIN RESULTS

Medline, Cochrane Library, Google scholar, and EMBASE databases were searched from inception to June 2021. Fourteen RCTs involving 1148 patients in total undergoing elective surgery published from 2012 to 2021 were included. QoR-40 scores were evaluated at postoperative 24 h (12 trials), 72 h (one trial), and Day 5 (one trial), respectively. Pooled results revealed significantly higher global [mean difference (MD) = 9.65, 95% confidence interval (CI): 6.33 to 12.97; I² = 97%; 13 RCTs; n = 1085] and individual dimension QoR-40 scores in the lidocaine group than those in placebo group. Subgroup analysis demonstrated no significant impact of the type of surgery, age, gender, surgical time, anesthetic technique, lidocaine dosage, and time of assessment on global QoR-40 scores. The use of intravenous lidocaine was associated with a significant reduction in intraoperative remifentanil consumption compared with that in the placebo group (standardized MD = -0.91, 95%CI: -1.32 to -0.51; I² = 86%; 10 RCTs; n = 799). There was no difference in risk of CPSP between the two groups [relative risk (RR) = 0.65, 95%CI: 0.33 to 1.25; I² = 58%; 4 RCTs; n = 309].

CONCLUSION

Our results verified the efficacy of intravenous lidocaine for enhancing postoperative quality of recovery by using a validated subjective tool and reducing intraoperative remifentanil consumption in patients receiving elective surgery under general anesthesia. Further studies are warranted to verify its efficacy in the acute care setting.

Local Anesthetic Lidocaine and Cancer: Insight Into Tumor Progression and Recurrence

Cancer is a leading contributor to deaths worldwide. Surgery is the primary treatment for resectable cancers. Nonetheless, it also results in inflammatory response, angiogenesis, and stimulated metastasis. Local anesthetic lidocaine can directly and indirectly effect different cancers. The direct mechanisms are inhibiting proliferation and inducing apoptosis via regulating PI3K/AKT/mTOR and caspase-dependent Bax/Bcl2 signaling pathways or repressing cytoskeleton formation. Repression invasion, migration, and angiogenesis through influencing the activation of TNFα-dependent, Src-induced AKT/NO/ICAM and VEGF/PI3K/AKT signaling pathways. Moreover, the indirect influences are immune regulation, anti-inflammation, and postoperative pain relief. This review summarizes the latest evidence that revealed potential clinical benefits of lidocaine in cancer treatment to explore the probable molecular mechanisms and the appropriate dose.

Pharmacotherapy for the Prevention of Chronic Pain after Surgery in Adults: An Updated Systematic Review and Meta-analysis

BACKGROUND

Chronic postsurgical pain can severely impair patient health and quality of life. This systematic review update evaluated the effectiveness of systemic drugs to prevent chronic postsurgical pain.

METHODS

The authors included double-blind, placebo-controlled, randomized controlled trials including adults that evaluated perioperative systemic drugs. Studies that evaluated same drug(s) administered similarly were pooled. The primary outcome was the proportion reporting any pain at 3 or more months postsurgery.

RESULTS

The authors identified 70 new studies and 40 from 2013. Most evaluated ketamine, pregabalin, gabapentin, IV lidocaine, nonsteroidal anti-inflammatory drugs, and corticosteroids. Some meta-analyses showed statistically significant-but of unclear clinical relevance-reductions in chronic postsurgical pain prevalence after treatment with pregabalin, IV lidocaine, and nonsteroidal anti-inflammatory drugs. Meta-analyses with more than three studies and more than 500 participants showed no effect of ketamine on prevalence of any pain at 6 months when administered for 24 h or less (risk ratio, 0.62 [95% CI, 0.36 to 1.07]; prevalence, 0 to 88% ketamine; 0 to 94% placebo) or more than 24 h (risk ratio, 0.91 [95% CI, 0.74 to 1.12]; 6 to 71% ketamine; 5 to 78% placebo), no effect of pregabalin on prevalence of any pain at 3 months (risk ratio, 0.88 [95% CI, 0.70 to 1.10]; 4 to 88% pregabalin; 3 to 80% placebo) or 6 months (risk ratio, 0.78 [95% CI, 0.47 to 1.28]; 6 to 68% pregabalin; 4 to 69% placebo) when administered more than 24 h, and an effect of pregabalin on prevalence of moderate/severe pain at 3 months when administered more than 24 h (risk ratio, 0.47 [95% CI, 0.33 to 0.68]; 0 to 20% pregabalin; 4 to 34% placebo). However, the results should be interpreted with caution given small study sizes, variable surgical types, dosages, timing and method of outcome measurements in relation to the acute pain trajectory in question, and preoperative pain status.

CONCLUSIONS

Despite agreement that chronic postsurgical pain is an important topic, extremely little progress has been made since 2013, likely due to study designs being insufficient to address the complexities of this multifactorial problem.

EDITOR’S PERSPECTIVE

Lidocaine infusion, basics and clinical issues

Optimum pain management, minimizing chronic complications and ensuring a good safety profile, is growing in importance day by day. Lidocaine infusion has an adequate safety profile and several desirable characteristics in the clinical setting. This review describes the characteristics of this drug, as well as its potential indications. Moreover, it describes the basic concepts around lidocaine use, mechanisms of action and clinical applications, as well as the use of infusions in acute pain and repercussions in chronic pain. A review of the literature in English and Spanish was conducted in several databases, with no publication date limit. Articles considered relevant, without including the grey literature, were selected independently. Lidocaine infusion is an option for acute postoperative pain control in major surgery and contributes to opioid sparing and reduced length of stay, with ample evidence in abdominal surgery, rendering it an option to recommend in various protocols. It has an acceptable safety profile in special populations and it is considered useful to diminish the incidence of persistent, chronic and neuropathic pain related to the surgical procedure.

A pilot multicentre randomised controlled trial of lidocaine infusion in women undergoing breast cancer surgery

Chronic postoperative pain is common after breast cancer surgery. Peri-operative lidocaine infusion may prevent the development of chronic postoperative pain, but a large-scale trial is required to test this hypothesis. It is unclear whether a pragmatic, multicentre trial design that is consistent with expert guidance, addresses the limitations of previous studies, and overcomes existing translational barriers is safe, effective and feasible. We conducted a double-blind, randomised controlled pilot study in 150 patients undergoing breast cancer surgery across three hospitals in Western Australia. Patients received lidocaine, or equivalent volumes of saline, as an intravenous bolus (1.5 mg.kg^-1 ) and infusion (2 mg.kg^-1 .h^-1 ) intra-operatively, and a subcutaneous infusion (1.33 mg.kg^-1 .h^-1 ) postoperatively for up to 12 h on a standard surgical ward, with novel safety monitoring tools in place. The co-primary outcomes were: in-hospital safety events; serum levels of lidocaine during intravenous and subcutaneous infusion; and annualised enrolment rates per site with long-term data capture. In-hospital safety events were rare, and similar in the placebo and lidocaine arms (3% vs. 1%). Median (IQR [range]) serum lidocaine levels during intravenous (2.16 (1.74-2.83 [1.12-6.06]) µg.ml^-1 , n = 41) and subcutaneous (1.52 (1.28-1.83 [0.64-2.85]) µg.ml^-1 , n = 48) infusion were comparable with previous trials reporting improved pain outcomes. Annualised enrolment approximated 50 patients per site per year, with high levels of protocol adherence and ≥ 99% capture of outcomes at 3 and 6 months. The adjusted odds ratio (95%CI) for postoperative pain at 6 months in the lidocaine arm was 0.790 (0.370-1.684). We conclude that this trial, as designed, is safe, effective and feasible in patients undergoing breast cancer surgery, and a larger-scale trial is planned.

Influence of volatile anesthesia versus total intravenous anesthesia on chronic postsurgical pain after cardiac surgery using the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials criteria: study protocol for a prospective randomized controlled trial

Background

Many patients develop chronic postsurgical pain (CPSP) after cardiac surgery, which interferes with their sleep, mood, and quality of life. Studies have suggested that propofol improves postoperative analgesia compared with volatile anesthetics, but its preventive effect on CPSP following cardiac surgery is still unknown. This study compares the incidence of CPSP following cardiac surgery for those receiving volatile anesthesia and those receiving propofol-based total intravenous anesthesia (TIVA) using criteria recommended by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT).

Methods/design

This is a prospective randomized controlled trial. In total, 500 adults undergoing cardiac surgery will be randomly allocated to the volatile or the TIVA group. The volatile group will receive sevoflurane or desflurane during surgery as general anesthesia. The TIVA group will receive propofol-based intravenous agents and no volatile agents during surgery. The primary outcomes will be the frequency of CPSP at 3 months, 6 months, and 1 year after surgery. In this case, CPSP is sternal or thoracic pain. It is defined as either (1) numerical rating scale (NRS) > 0 or (2) meeting all six IMMPACT criteria for CPSP. The IMMPACT criteria are validated pain instruments.

Discussion

To our knowledge, this is the first prospective randomized controlled trial to investigate the prevention of CPSP following cardiac surgery for patients receiving volatile anesthesia compared to those receiving propofol-based TIVA using validated pain instruments in accordance with the IMMPACT recommendations. This study will provide important information on which of these two anesthetic regimens is better for preventing CPSP after cardiac surgery.

Trial registration

Chictr.org.cn, ChiCTR1900020747. Registered on 16 January 2019.

Chronic postsurgical pain and cancer: the catch of surviving the unsurvivable

PURPOSE OF REVIEW

Chronic postsurgical pain (CPSP) is an important and well recognized cause of much long-term suffering, which in some cases may be preventable and affects many people living with cancer. Unfortunately, general consensus is lacking as to how best reduce the risk of developing CPSP.

RECENT FINDINGS

Cancer is now not always a short-lived, fatal disease and is now moving towards a chronic illness. Poorly managed perioperative pain is the greatest risk factor for CPSP. Recent trials have examined preventive strategies for CPSP associated with breast surgery and thoracotomy, two operations used in cancer treatment. Standard antinociceptive drugs, 5% lidocaine patches and ketamine do not prevent CPSP. The evidence for gabapentinoids is conflicting. Intravenous lidocaine and, separately, regional anaesthesia appear beneficial.

SUMMARY

Well-managed pain, irrespective of technique, reduces the risk of CPSP. The literature is inconclusive regarding an 'optimal approach.' Regional anaesthesia, intravenous lidocaine and the aggressive management of perioperative pain using multimodal analgesia including antineuropathic pain agents such as gabapentinoids and certain antidepressants are recommended. Clinicians should not rely on general anaesthesia, opioids, NSAIDs and ketamine to prevent CPSP. A blanket approach using gabapentinoids for all patients undergoing major surgery is not indicated. Instead, the presence of perioperative neuropathic pain should be checked for regularly.

Chronified Pain Following Operative Procedures

BACKGROUND

Over 18 million operative procedures are performed each year in Germany alone. Approximately 10% of surgical patients develop moderate to severe chronic post-surgical pain (CPSP), which can severely impair their quality of life. The pain must persist for at least three months to be called chronic; pain that arises after a symptom-free interval is not excluded. The perioperative use of local anesthetic agents may lessen the incidence of CPSP.

METHODS

We selectively reviewed the pertinent literature, including two current Cochrane Reviews. Local and regional anesthetic techniques are discussed, as is the intravenous administration of lidocaine.

RESULTS

The main risk factors for CPSP are pre-existing (preoperative) chronic pain, opioid intake, a pain-related catastrophizing tendency, intraoperative nerve injury, and severe acute postoperative pain. CPSP is reported to be especially common after thoracic surgery, breast surgery, amputations, and orthopedic procedures. Local and regional anesthetic techniques have been shown to significantly lower the incidence of CPSP after thoracotomy (number needed to treat for an additional beneficial outcome [NNTB] = 7), breast cancer surgery (NNTB = 7), and cesarean section (NNTB = 19). Intravenous lidocaine also lowers the incidence of CPSP after various types of procedures.

CONCLUSION

Local and regional anesthetic techniques and intravenous lidocaine lower the incidence of CPSP after certain types of operative procedures. The intravenous administration of lidocaine to prevent CPSP is off label and requires the patient's informed consent. The evidence for the measures presented here is of low to medium quality.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 39 studies, enrolling a total of 3027 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Continuous intravenous perioperative lidocaine infusion for postoperative pain and recovery in adults

BACKGROUND

The management of postoperative pain and recovery is still unsatisfactory in a number of cases in clinical practice. Opioids used for postoperative analgesia are frequently associated with adverse effects, including nausea and constipation, preventing smooth postoperative recovery. Not all patients are suitable for, and benefit from, epidural analgesia that is used to improve postoperative recovery. The non-opioid, lidocaine, was investigated in several studies for its use in multimodal management strategies to reduce postoperative pain and enhance recovery. This review was published in 2015 and updated in January 2017.

OBJECTIVES

To assess the effects (benefits and risks) of perioperative intravenous (IV) lidocaine infusion compared to placebo/no treatment or compared to epidural analgesia on postoperative pain and recovery in adults undergoing various surgical procedures.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and reference lists of articles in January 2017. We searched one trial registry contacted researchers in the field, and handsearched journals and congress proceedings. We updated this search in February 2018, but have not yet incorporated these results into the review.

SELECTION CRITERIA

We included randomized controlled trials comparing the effect of continuous perioperative IV lidocaine infusion either with placebo, or no treatment, or with thoracic epidural analgesia (TEA) in adults undergoing elective or urgent surgery under general anaesthesia. The IV lidocaine infusion must have been started intraoperatively, prior to incision, and continued at least until the end of surgery.

DATA COLLECTION AND ANALYSIS

We used Cochrane's standard methodological procedures. Our primary outcomes were: pain score at rest; gastrointestinal recovery and adverse events. Secondary outcomes included: postoperative nausea and postoperative opioid consumption. We used GRADE to assess the quality of evidence for each outcome.

MAIN RESULTS

We included 23 new trials in the update. In total, the review included 68 trials (4525 randomized participants). Two trials compared IV lidocaine with TEA. In all remaining trials, placebo or no treatment was used as a comparator. Trials involved participants undergoing open abdominal (22), laparoscopic abdominal (20), or various other surgical procedures (26). The application scheme of systemic lidocaine strongly varies between the studies related to both dose (1 mg/kg/h to 5 mg/kg/h) and termination of the infusion (from the end of surgery until several days after).The risk of bias was low with respect to selection bias (random sequence generation), performance bias, attrition bias, and detection bias in more than 50% of the included studies. For allocation concealment and selective reporting, the quality assessment yielded low risk of bias for only approximately 20% of the included studies.IV Lidocaine compared to placebo or no treatment We are uncertain whether IV lidocaine improves postoperative pain compared to placebo or no treatment at early time points (1 to 4 hours) (standardized mean difference (SMD) -0.50, 95% confidence interval (CI) -0.72 to -0.28; 29 studies, 1656 participants; very low-quality evidence) after surgery. Due to variation in the standard deviation (SD) in the studies, this would equate to an average pain reduction of between 0.37 cm and 2.48 cm on a 0 to 10 cm visual analogue scale . Assuming approximately 1 cm on a 0 to 10 cm pain scale is clinically meaningful, we ruled out a clinically relevant reduction in pain with lidocaine at intermediate (24 hours) (SMD -0.14, 95% CI -0.25 to -0.04; 33 studies, 1847 participants; moderate-quality evidence), and at late time points (48 hours) (SMD -0.11, 95% CI -0.25 to 0.04; 24 studies, 1404 participants; moderate-quality evidence). Due to variation in the SD in the studies, this would equate to an average pain reduction of between 0.10 cm to 0.48 cm at 24 hours and 0.08 cm to 0.42 cm at 48 hours. In contrast to the original review in 2015, we did not find any significant subgroup differences for different surgical procedures.We are uncertain whether lidocaine reduces the risk of ileus (risk ratio (RR) 0.37, 95% CI 0.15 to 0.87; 4 studies, 273 participants), time to first defaecation/bowel movement (mean difference (MD) -7.92 hours, 95% CI -12.71 to -3.13; 12 studies, 684 participants), risk of postoperative nausea (overall, i.e. 0 up to 72 hours) (RR 0.78, 95% CI 0.67 to 0.91; 35 studies, 1903 participants), and opioid consumption (overall) (MD -4.52 mg morphine equivalents , 95% CI -6.25 to -2.79; 40 studies, 2201 participants); quality of evidence was very low for all these outcomes.The effect of IV lidocaine on adverse effects compared to placebo treatment is uncertain, as only a small number of studies systematically analysed the occurrence of adverse effects (very low-quality evidence).IV Lidocaine compared to TEAThe effects of IV lidocaine compared with TEA are unclear (pain at 24 hours (MD 1.51, 95% CI -0.29 to 3.32; 2 studies, 102 participants), pain at 48 hours (MD 0.98, 95% CI -1.19 to 3.16; 2 studies, 102 participants), time to first bowel movement (MD -1.66, 95% CI -10.88 to 7.56; 2 studies, 102 participants); all very low-quality evidence). The risk for ileus and for postoperative nausea (overall) is also unclear, as only one small trial assessed these outcomes (very low-quality evidence). No trial assessed the outcomes, 'pain at early time points' and 'opioid consumption (overall)'. The effect of IV lidocaine on adverse effects compared to TEA is uncertain (very low-quality evidence).

AUTHORS' CONCLUSIONS

We are uncertain whether IV perioperative lidocaine, when compared to placebo or no treatment, has a beneficial impact on pain scores in the early postoperative phase, and on gastrointestinal recovery, postoperative nausea, and opioid consumption. The quality of evidence was limited due to inconsistency, imprecision, and study quality. Lidocaine probably has no clinically relevant effect on pain scores later than 24 hours. Few studies have systematically assessed the incidence of adverse effects. There is a lack of evidence about the effects of IV lidocaine compared with epidural anaesthesia in terms of the optimal dose and timing (including the duration) of the administration. We identified three ongoing studies, and 18 studies are awaiting classification; the results of the review may change when these studies are published and included in the review.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 41 studies, enrolling a total of 3143 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.