Preventing pain after breast surgery: A systematic review with meta-analyses and trial-sequential analyses

Interpectoral nerve blocks may lower postoperative narcotic use after mastectomy

BACKGROUND

Pain management following mastectomy is a significant challenge often requiring opioids. Nonopioid pain management utilizing nerve blocks has been shown in other fields to reduce postoperative opioid use and may be effective for postoperative pain in mastectomy patients. The primary purpose of this study was to compare postoperative opioid use, measured in morphine milligram equivalents (MME), between mastectomy patients who underwent interpectoral nerve block (IPNB) and a historical control group. Secondary outcomes included length of stay (LOS) and postoperative pain scores.

METHODS

This is a single-center, retrospective cohort study. The charts of women who underwent mastectomy for cancer without immediate reconstruction from 10/2017-12/2019 were reviewed. Wilcoxon rank sum test was used for unadjusted analysis and multiple linear regression for adjusted analysis.

RESULTS

There were 105 patients included in this study, of which 37 (35%) underwent IPNB. In unadjusted analysis, median MME use was significantly lower in patients that received IPNB compared to the control group (IPNB = 5, controls = 17, p = 0.03). Patients that received IPNB had an observed reduction in LOS and postoperative pain, though these results failed to reach statistical significance. There were no IPNB-related complications.

CONCLUSIONS

IPNB may be an effective strategy to decrease postoperative opioid use in mastectomy patients. Larger, prospective studies are needed to further investigate the effectiveness of IPNB.

Basic analgesic use in randomised trials assessing local and regional analgesic interventions for mastectomy: a critical appraisal and clinical implications

Regional analgesia is a core component of an optimal multimodal analgesia technique. Several advanced regional analgesic techniques have been evaluated for mastectomy; however, the optimal choice remains unclear. Many randomised clinical trials (RCTs) evaluating various local/regional analgesic techniques do not include basic analgesics (i.e. paracetamol, non-steroidal anti-inflammatory drugs, cyclooxygenase-2 specific inhibitors, and dexamethasone) which precludes objective evaluation of their efficacy. The aim of this scoping review was to assess the use of basic analgesics in RCTs evaluating efficacy of local and regional analgesic techniques in patients undergoing mastectomy. PubMed was searched to identify relevant articles from January 1, 2010 to May 31, 2023. The key finding of this study is that almost 90% (n=82/92) of the RCTs evaluating local/regional analgesic techniques in patients undergoing mastectomy did not administer well accepted basic analgesics in the comparator groups. Consequently, the conclusions of the RCTs assessing local/regional analgesic techniques for mastectomy should be interpreted with caution. Also, clinical guidelines based on meta-analyses of these RCTs could be inadequate or inappropriate.

Improving well-being for individuals with persistent pain after surgery for breast cancer, lobular carcinoma in situ, or ductal carcinoma in situ: A randomized clinical trial

>276,000 Americans will be diagnosed with invasive breast cancer, lobular carcinoma in situ, or ductal carcinoma in situ this year and most will undergo breast surgery as part of their care. Although prognosis is excellent, many patients experience persistent post-surgical pain (PSP), which has no satisfactory pharmacological treatment. The causal contributions of pain-associated psychological factors (e.g., catastrophic thoughts about pain, psychological flexibility, self-efficacy) to the continuing burden of PSP have not yet been determined and may be opportune intervention targets. The randomized trial described here will compare the benefits of three manualized behavioral interventions for individuals with PSP. Participants will receive either: 1) self-guided health education (SGHE); 2) interventionist-guided health education (IGHE); or 3) interventionist-guided pain coping skills training with elements of acceptance and commitment therapy that specially target catastrophic thoughts about pain, self-efficacy, and psychological flexibility (CST-PSP). Participants will prospectively complete validated assessments of primary outcomes (PSP severity and interference) at baseline (pre-intervention) and 3-, 6-, and 12-months later. Validated measures of emotional distress and cancer-specific distress will be assessed as secondary outcomes. To test their roles as drivers of PSP, catastrophic thoughts about pain, self-efficacy, and psychological flexibility, will be assessed and statistically analyzed as mediators of hypothesized beneficial effects. The interventions' impacts on pain sensitivity and central sensitization will be investigated to test these physiological pathways as proximal drivers of PSP. To better characterize the patient experience, additional validated measures will be explored for associations with PSP, along with demographic and clinical factors. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04225585, registered January 13, 2020.

Quality of meta-analyses of non-opioid, pharmacological, perioperative interventions for chronic postsurgical pain: a systematic review

Background

In an attempt to aggregate observations from clinical trials, several meta-analyses have been published examining the effectiveness of systemic, non-opioid, pharmacological interventions to reduce the incidence of chronic postsurgical pain.

Objective

To inform the design and reporting of future studies, the purpose of our study was to examine the quality of these meta-analyses.

Evidence review

We conducted an electronic literature search in Embase, MEDLINE, and the Cochrane Database of Systematic Reviews. Published meta-analyses, from the years 2010 to 2020, examining the effect of perioperative, systemic, non-opioid pharmacological treatments on the incidence of chronic postsurgical pain in adult patients were identified. Data extraction focused on methodological details. Meta-analysis quality was assessed using the A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) critical appraisal tool.

Findings

Our search yielded 17 published studies conducting 58 meta-analyses for gabapentinoids (gabapentin and pregabalin), ketamine, lidocaine, non-steroidal anti-inflammatory drugs, and mexiletine. According to AMSTAR 2, 88.2% of studies (or 15/17) were low or critically low in quality. The most common critical element missing was an analysis of publication bias. Trends indicated an improvement in quality over time and association with journal impact factor.

Conclusions

With few individual trials adequately powered to detect treatment effects, meta-analyses play a crucial role in informing the perioperative management of chronic postsurgical pain. In light of this inherent value and despite a number of attempts, high-quality meta-analyses are still needed.

PROSPERO registration number

CRD42021230941.

Preoperative Paravertebral Block and Chronic Pain after Breast Cancer Surgery: A Double-blind Randomized Trial

BACKGROUND

The effectiveness of paravertebral block in preventing chronic pain after breast surgery remains controversial. The primary hypothesis of this study was that paravertebral block reduces the incidence of chronic pain 3 months after breast cancer surgery.

METHODS

In this prospective, multicenter, randomized, double-blind, parallel-group, placebo-controlled study, 380 women undergoing partial or complete mastectomy with or without lymph node dissection were randomized to receive preoperative paravertebral block with either 0.35 ml/kg 0.75% ropivacaine (paravertebral group) or saline (control group). Systemic multimodal analgesia was administered in both groups. The primary endpoint was the incidence of chronic pain with a visual analogue scale (VAS) score greater than or equal to 3 out of 10, 3 months after surgery. The secondary outcomes were acute pain, analgesic consumption, nausea and vomiting, chronic pain at 6 and 12 months, neuropathic pain, pain interference, anxiety, and depression.

RESULTS

Overall, 178 patients received ropivacaine, and 174 received saline. At 3 months, chronic pain was reported in 93 of 178 (52.2%) and 83 of 174 (47.7%) patients in the paravertebral and control groups, respectively (odds ratio, 1.20 [95% CI, 0.79 to 1.82], P = 0.394). At 6 and 12 months, chronic pain occurred in 104 of 178 (58.4%) versus 79 of 174 (45.4%) and 105 of 178 (59.0%) versus 93 of 174 (53.4%) patients in the paravertebral and control groups, respectively. Greater acute postoperative pain was observed in the control group 0 to 2 h (area under the receiver operating characteristics curve at rest, 4.3 ± 2.8 vs. 2.9 ± 2.8 VAS score units × hours, P < 0.001) and when maximal in this interval (3.8 ± 2.1 vs. 2.5 ± 2.5, P < 0.001) but not during any other interval. Postoperative morphine use was 73% less in the paravertebral group (odds ratio, 0.272 [95% CI, 0.171 to 0.429]; P < 0.001).

CONCLUSIONS

Paravertebral block did not reduce the incidence of chronic pain after breast surgery. Paravertebral block did result in less immediate postoperative pain, but there were no other significant differences in postoperative outcomes.

EDITOR’S PERSPECTIVE