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Abstract
Objective To determine which locoregional techniques are effective in managing post-operative pain in major open oncologic gynecologic surgery in terms of pain scores and opioid consumption when epidural analgesia is not a feasible option.
Methods A systematic review of the literature, based on the Preferred Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, was conducted. The ROB-2 assessment was used to assess bias. The primary outcomes were opioid consumption and post-operative pain scores. Secondary outcomes included post-operative markers such as time to mobilization and bowel movement.
Results A total of nine studies (n=714) were included in the analysis. Eight studies had a low risk of bias. Five different forms of locoregional analgesia were described. Eight studies compared with placebo and one study compared rectus sheath block with epidural analgesia. Three of the five studies investigating transversus abdominis plane (TAP) blocks showed an improvement in pain scores and opioid consumption when compared with the placebo group. One study investigating rectus sheath blocks and another investigating paravertebral blocks demonstrated significantly less opioid consumption and improved pain scores at certain time points. The studies investigating continuous wound infiltration and superior hypogastric plexus block found no significant effect. No adverse effects of locoregional anesthesia were found.
Conclusion Our study showed that TAP blocks, rectus sheath blocks, and paravertebral blocks may decrease opioid consumption and improve pain scores in patients undergoing open abdominal surgery for gynecologic cancer. Additionally, these techniques might serve as a viable alternative for patients with contraindications to epidural analgesia.
- Pain
- Anesthesia, General
- Surgical Oncology
- Gynecologic Surgical Procedures
- Gynecology
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, an indication of whether changes were made, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Current literature acknowledges the opioid-sparing benefits of locoregional anesthesia. While various techniques have been introduced, their comparative efficacy remains largely unexplored.
WHAT THIS STUDY ADDS
Transversus abdominis plane blocks, rectus sheath blocks, and paravertebral blocks can be useful additions to multimodal analgesia, offering a viable alternative for epidural analgesia.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
Current Enhanced Recovery After Surgery (ERAS) guidelines support the routine use of epidural analgesia. The decreased availability of epidural analgesia following gynecologic malignancy surgeries necessitates the integration of opioid-sparing locoregional analgesic methods. Alternative analgesia methods are essential for future research and align with the current trend towards optimizing post-operative recovery/mobilization and pain management.
Introduction
The management of post-operative pain is a crucial aspect of Enhaced Recovery After Surgery (ERAS). It is one of the factors that impacts the length of stay and patient satisfaction.1 2 Surgery for gynecologic malignancies often consists of major abdominal procedures resulting in significant post-operative pain.3 4 Although epidural analgesia is considered the current gold standard for laparotomy, its use has decreased in the past years due to potential adverse effects such as (post-operative) hypotension, urinary retention, and delayed mobilization.5 Furthermore, there is a growing patient population with a contraindication for epidural analgesia, mainly due to the use of anticoagulants.
When epidural analgesia is not feasible, systemic opioids in combination with other analgesics are commonly used peri-operatively. The current trend for post-operative pain management is the use of multimodal post-operative analgesia.6 However, the opioid epidemic and post-operative opioid-related complications have prompted us to be critical and careful when prescribing opioids. All these factors have resulted in a search for opioid-sparing locoregional techniques such as continuous wound infiltration and various abdominal wall blocks (rectus sheath blocks and transversus abdominis plane (TAP) blocks).7 These techniques may be useful alternatives as a contribution to multimodal systemic analgesia. However, the optimal block with regard to pain scores and opioid consumption in this patient category has not yet been extensively researched.
This study aims to determine which locoregional technique is effective in managing post-operative pain in major open oncologic gynecologic surgery in terms of pain scores and opioid consumption when epidural analgesia is not a feasible option or preferred by the patient.
Methods
A systematic review of the literature, based on the Preferred Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, was conducted. The checklist is shown in Online Supplemental File 18 The protocol for this review was registered in PROSPERO (CRD42023460486). The search was conducted in Medline, Embase, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and Google Scholar (100 top-ranked) and was executed in September 2023 using the following keywords: Laparotomy, Gynecological cancer, and Anesthesia. The inclusion criteria were: randomized controlled trial, adult patients scheduled for laparotomy for gynecologic oncologic surgery, receiving locoregional analgesia compared with epidural anesthesia or placebo. The full search for each database is shown in Online Supplemental File 2.
Supplemental material
Supplemental material
The title and abstract of the obtained records as well as subsequently full-text articles were independently screened for eligibility by two researchers (LAD and MSV) using Endnote. Disagreements were resolved through consultation with a third researcher (MD). The quality assessment of eligible studies was independently conducted by both researchers (LAD and MSV) using the Risk-of-bias version 2 (ROB-2) assessment. Data extraction was executed by two researchers (LAD and MSV). Extracted data included various aspects including sample size, age, type of locoregional anesthesia, pain scores, opioid consumption, and secondary outcomes.
The primary outcomes evaluated were opioid consumption and post-operative pain scores. Secondary outcomes included time to mobilization, bowel mobility, and patient satisfaction.
Results
The search resulted in a total of 828 articles, which was reduced to 538 articles after de-duplication. Of these, 460 were excluded based on title and abstract. The remaining 78 articles were assessed for eligibility for inclusion based on full text. A total of nine articles met all the inclusion criteria and are included in this review (Figure 1). The nine included studies were published between 2005 and 2023 and resulted in a total sample size of 714 patients. Five studies included surgery using midline laparotomy, two studies using mostly midline laparotomy and a small percentage Pfannestiel incision and two studies did not specify the surgical approach (Table 1).
Flowchart showing the inclusion process for the articles identified in the search, detailing the stages and reasons for exclusion. After extensive screening, a total of nine studies were included in the review.
Study characteristics of included studies
Using the ROB-2 assessment, eight of the nine studies showed a low risk of bias. One study showed some concerns due to uncertainty about the allocation of intervention concealment and carers being aware of the intervention given (Table 2).
Risk of bias (ROB)-2 assessment
Locoregional Analgesia Techniques
Five different forms of locoregional analgesia were described (TAP blocks, paravertebral blocks, rectus sheath blocks, continuous wound infiltration, and superior hypogastric blocks). Five studies described the use of TAP blocks compared with placebo.9–13 Melnikov et al compared either thoracic paravertebral blocks or TAP blocks with placebo.11 Two studies reported on the effect of continuous rectus sheath blocks, comparing them with either epidural analgesia or placebo.14 15 Kushner et al described the efficacy of continuous wound infiltration compared with placebo and Subramanian et al compared the efficacy of a superior hypogastric plexus block with placebo.16 17
Pain
Eight of the nine studies described the outcome of pain using the numeric rating scale (NRS), while one study reported on this using the Wisconsin Brief Pain Inventory.16 Three of five studies reporting on TAP blocks compared with placebo found a significant decrease in NRS.11–13 In the study by Melnikov et al, the assessment of NRS at various intervals during rest and during coughing showed a significant reduction in both TAP block and paravertebral block across all time points, except at rest at 48 hours where only the paravertebral block had a significantly lower NRS.11 Zhang et al compared different local anesthetics and concentrations with placebo and found lower NRS at rest at 3 hours in the 0.375% ropivacaine group versus placebo. They also found that the use of 0.4% and 0.6% compound lidocaine led to reduced NRS at rest until 12 hours post-operatively.12 Yoshida et al found significantly reduced pain scores in the intervention group during coughing at 1 hour and 24 hours after catheter placement,13 while Bernard et al and Griffiths et al found no significant decrease in pain scores compared with placebo (Table 3).9 10
Primary outcomes pain and opiod consumption of included studies
Bakshi et al compared rectus sheath blocks with placebo and found a significant decrease in worst median NRS at 48 hours at rest and during movement.14 Kuniyoshi et al found that, compared with epidural analgesia, rectus sheath blocks demonstrated non-inferiority at rest up to 36 hours and even superiority at 24 hours post-operatively. Moreover, they found that rectus sheath blocks were neither inferior nor non-inferior to epidural analgesia at movement at different time points.15
Subramanian et al compared superior hypogastric plexus block plus continuous wound infiltration with continuous wound infiltration alone and found significantly lower pain scores up to 24 hours post-operatively.17 Kushner et al compared continuous wound infiltration with placebo and found no significant differences in mean 5-day Wisconsin Brief Pain Inventory scores nor in the least or worst pain experienced.16
Opioid Consumption
Three studies found a significant reduction in opioid consumption.11–13 Melnikov et al found that patients receiving TAP blocks required significantly less ketobemidon (an opioid with N-methyl-D-aspartate antagonist properties) at 6 hours post-operatively, as well as in both intervention groups at 24 and 48 hours.11 Similarly, Yoshida et al found lower cumulative morphine consumption 24 hours after catheter placement in the intervention group.13 Furthermore, Zhang et al reported that all intervention groups needed significantly less sufentanil than the placebo group at different time intervals.12 However, two studies did not find any significant decrease in opioid consumption.9 10
Bakshi et al found a significant reduction in the mean morphine consumption in the intervention group at both 24 hours and 48 hours.14 Kuniyoshi et al found that, compared with epidural analgesia, there was no significant difference in the effective frequency of use of rescue analgesics (IV patient-controlled anesthesia).15 Subramanian et al found a significant decrease in morphine consumption in the group receiving superior hypogastric plexus block up to 48 hours post-operatively,17 and Kushner et al found no significant differences in opioid consumption with the use of continuous wound infiltration.16
Secondary Outcomes
Secondary outcomes, including length of stay, time to mobilization, and adverse analgesic events are shown in Table 4. Not all studies reported on these outcomes. Two studies found a significantly earlier time to mobilization,14 17 two studies showed improved bowel motility and a decrease in post-operative nausea and vomiting,12 14 and three studies showed higher patient satisfaction in the block groups.11 12 14 No serious adverse events related to locoregional techniques were reported.
Secondary outcomes of included studies between intervention and control group
Discussion
Summary of Main Findings
We found five studies reporting a positive result regarding pain and opioid consumption with the use of locoregional techniques in patients undergoing major open surgery for gynecologic malignancies. TAP blocks, rectus sheath blocks, and paravertebral block showed a significant improvement in pain scores and decreased opioid use when compared with placebo, and rectus sheath block was non-inferior compared with epidural analgesia.11–15 No significant effect of continuous wound infiltration was found.16 Furthermore, two studies indicated a significantly earlier time to mobilization,14 17 two showed improved bowel motility and a decrease in post-operative nausea and vomiting,12 14 and three studies demonstrated higher patient satisfaction in the block groups.11 12 14
Results in the Context of Published Literature
Three studies have described a positive outcome with the use of TAP blocks compared with placebo as either a single-shot technique, continuous block, or the use of a long-acting local anesthetic.11–13 Each of these demonstrated a significant decrease in opioid consumption and pain scores, Yoshida et al being the only study uing the oblique sub-costal TAP approach and Zhang et al using different concentrations of compound lidocaine (a long-acting local anesthetic mixture of lidocaine, menthol, and glycerin) only registered for use in China.
The aim of using catheters or long-acting local anesthetics is to ensure a prolonged analgesic effect. Catheter-related problems such as displacement can, however, deter the use of them.18 Liposomal bupivacaine is a long-acting local anesthetic registered in the USA since 2011, the EU since 2020, and the UK since 2021, and may be a viable alternative to locoregional catheters.19 20 However, none of the included studies have investigated the effect of liposomal bupivacaine.21 Meyer et al did study the use of liposomal bupivacaine versus standard bupivacaine in wound infiltration in open gynecologic surgery and found no significant effect on opioid use,22 neither was the effect of continuous wound infiltration in our review. More research is warranted on the use of liposomal bupivacaine in locoregional blocks, since it is more widely registered than compound lidocaine, before conclusions can be drawn. There is insufficient data from this review to support the use of locoregional catheters as the follow-up of outcomes was too short to demonstrate a benefit over the single-shot technique.
In two studies the effect of single-shot TAP block versus placebo was investigated and produced no significant results.9 10 In both studies the accuracy of block placement could have influenced the outcome. Bernard et al investigated the use of surgically placed TAP blocks via a transperitoneal approach using the fascial ‘pop’ technique without ultrasound guidance.9 As demonstrated by Bakshi et al, ultrasound guidance can be used to verify and correct needle placement in blocks.14 The negative outcome of single-shot TAP blocks by Griffiths et al was not surprising as its effect is not expected to be present at 24 hours post-operatively. Furthermore, the placement as described by Griffiths et al might not have been accurate enough for optimal analgesia. As described by Tsai et al, the posterior approach to the TAP block anesthetizes the lateral cutaneous branches of the main thoracolumbar nerves and thereby improves analgesia of the lateral and paramedian abdominal wall.23 This effect could be missed if the needle position is too ventral and might have an impact on analgesia and opioid consumption.
Melnikov et al found that thoracic paravertebral blocks were superior to TAP blocks with regard to opioid consumption. This superiority could be accounted for by the possible visceral analgesia provided by paravertebral blocks.24 Ultrasound-guided rectus sheath blocks are indicated for umbilical surgery or midline laparotomy.25 Needle placement and injection of local anesthetic just ventral to the posterior rectus sheath provides analgesia in the midline from T7 to T12.25 Bakshi et al described the use of surgically placed rectus sheath catheters, whose needle position was verified and corrected by ultrasound guidance, with significant effect on pain and opioid consumption. This study highlights the importance of correct catheter placement.14 The other study investigating rectus sheath catheters demonstrated non-inferior pain scores when compared with epidural analgesia with similar opioid consumption in both groups,15 which could be seen as an advantage and make rectus sheath catheters a viable alternative when epidural analgesia is not feasible. Subramanian et al described the use of a superior hypogastric plexus block as an alternative to a neuraxial technique and demonstrated a significant decrease in opioid consumption and a reduction in pain scores. This technique is usually used for the management of chronic pelvic pain and is not usually part of the armamentarium of the peri-operative anesthesiologist.17
Severe acute post-operative pain occurring within 2 weeks after surgery is a predictor for the development of chronic post-surgical pain.26 27 However, the included studies had a maximum follow-up of 5 days and did not encompass opioid use or NRS scores during the first 2 weeks post-operatively. Consequently, these studies could not provide insights into the role of these analgesic techniques in chronic post-surgical pain. Furthermore, none of the included studies assessed pre-operative pain or opioid use. Future research incorporating a follow-up period of 2 weeks and assessment of pre-operative pain and opioid use could support the use of locoregional analgesic techniques and determine its role in chronic post-surgical pain.
As not all studies reported on the secondary outcomes, no definite conclusions of the advantage of locoregional techniques over placebo or epidural analgesia concerning length of stay, incidence of post-operative nausea and vomiting, opioid-related adverse events, or bowel motility could be made. However, the available data suggest that locoregional techniques may have a positive effect on bowel mobility, time to mobilization, and a decrease in post-operative nausea and vomiting which can have an enhanced effect on recovery in the post-operative period, adding to the positive effect of reduced pain and opioids.
Strength and Weaknesses
The study population has been limited to women undergoing oncologic gynecologic surgery, which limits the generalizability of the results. However, this focused approach can be considered a strength as it provides robust evidence specifically for this patient group. We did not include studies comparing different locoregional techniques or studies comparing different local anesthetic compositions if they did not include either an epidural group or a placebo group, so we could have missed important findings. Furthermore, standardized pain management changed within the timeframe of the selected papers. Moreover, meta-analysis was not possible since data were heterogenous and some data needed were not presented in the published studies. Efforts to obtain the information from authors proved unsuccessful.
Implications for Further Research
More research is needed to confirm the positive effect of TAP, rectus sheath, and paravertebral blocks and to compare these techniques with each other in order to determine the best locoregional analgesia technique. It is recommended to incorporate a follow-up period of at least 2 weeks and to consider assessing pre-operative pain and opioid use in further research to strengthen the evidence supporting the use of locoregional analgesic techniques and to determine their role in chronic post-surgical pain.
Conclusion
This review found that TAP, rectus sheath, and paravertebral blocks, when placed correctly, can decrease opioid consumption and improve pain scores. It also showed that these locoregional techniques, as part of a multimodal analgesic regime, may enhance recovery during the early post-operative period in patients undergoing open abdominal surgery for gynecologic cancer. Additionally, these techniques might serve as a viable alternative for patients with contraindications for epidural analgesia. Further research is warranted to strengthen and prove these results and to compare these modalities with each other.
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
Ethics statements
Patient consent for publication
Ethics approval
Not applicable.
Acknowledgments
The authors wish to thank MFM Engel from the Erasmus MC Medical Library for developing and updating the search strategies.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Contributors All authors contributed to the realization and conceptualization of this paper. LAD and MSV performed the search, screened the articles, extracted the data and did the quality assessment and wrote down the results. All authors have thoroughly read, revised, and approved several versions of the manuscript and agreed to this submission. The guarantor of this paper is LAD.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.