Acute Pain Management for Gynecologic Surgery and a Succinct Guide to Regional Anesthesia,Including Nerve Blocks

Abstract

Effective and safe acute-pain management practices are imperative for patients undergoing gynecologic surgery. Well-managed perioperative pain is associated with fewer postoperative complications, decreased hospital lengths of stay, lower readmission rates, better functional capacity, and improved health-related quality of life. This article reviews the available analgesic modalities used to provide high-quality acute pain control for patients undergoing gynecologic surgery. These modalities include topical agents, wound and intraperitoneal infusions, regional anesthetics, neuraxial blocks, peripheral nerve stimulation, and opioid and nonopioid analgesics. This article focuses on when each technique can be practically integrated into clinical practice, based on a thorough review of the current evidence. (J GYNECOL SURG 39:271)

Introduction

Gynecologic surgeries are among the most-common procedures for adult women, and postoperative pain control remains a significant concern for surgical patients. Poorly managed acute postsurgical pain is associated with increased morbidity, functional impairment, health care cost, length of stay, and risk of developing chronic pain.

Opioids have long been a mainstay of pain control, despite their multifarious side-effects. Therefore, one of the pillars of Enhanced Recovery After Surgery (ERAS) protocols is multimodal postsurgical pain management and minimizing opioids. Strategies to reduce the use of opioids and achieve better pain control after surgery can improve patient care and reduce the development of chronic postsurgical pain and associated sequelae.

Regional anesthesia plays a significant role in pain control, and reduction of opioid requirements but is often poorly understood by clinical teams. This review provides a concise and easy guide to regional anesthesia techniques for maximizing their benefits in gynecologic surgery to improve pain management and reduce opioid usage. For a summary of different modalities of pain control, see Table 1.

Table 1.

Modalities of Pain Control by Mechanism

Pain-control modality	Mechanism	Summary of current evidence
Transduction of pain stimulus at site of injury
Topical agents/local	Blocking nociceptive signal at origin	Recommended bupivacaine or liposomal bupivacaine incision infiltration as a part of multimodal analgesia to minimize opioid use¹
Peritoneal local infusion	Blocking nociceptive signal at origin	Slight reduction of pain scores (at 6 & 24 hrs), compared to saline placebo & no reduction in LOS among patients who underwent laparoscopic gynecologic surgery³
Anti-inflammatory agents	Systemic, blocking nociceptive signal at origin	Recommended as a part of multimodal analgesia to minimize opioids¹
Para-aortic ganglia
SHP/presacral nerve	Blocking visceral nociceptive signals from pelvic & perineal organs	Largest published RCT did not show a significant reduction of pain scores or morphine equivalents among patients undergoing laparoscopic surgery⁷
Transmission of pain stimulus—regional anesthesia
TAP blocks	Blocking transmission of nociceptive signals from the abdominal wall	Meta-analysis of RCTs comparing TAP blocks to placebo or no block in laparoscopic or robotic hysterectomy patients showed no changes in VAS pain scores or opioid use (MED)⁹ For open procedures, TAP blocks may add to analgesia but should be performed under ultrasound guidance by experienced provider^10,11
QLB	Blocking transmission of nociceptive signals from the abdominal wall	Meta-analysis of 36 RCTs for open TAH for benign lesions reported that QLB results in lower pain scores at 6–8 hrs and 24 hrs but no change in 24-hr opioid consumption, compared to control or no block¹³
ESP block	Blocking transmission of nociceptive signals from the abdominal wall	Meta-analysis of 36 RCTs for open TAH for benign lesions found that ESP block results in lower 24-hr opioid consumption but no change in pain scores at 6–8 hrs & 24 hrs, compared to control or no block¹³
Pudendal block	Blocking transmission of nociceptive signals from the lower vagina, posterior perineum, & vulva	RCT of women undergoing pelvic reconstruction found no difference in pain scores, & opioid consumption was lower but not significant when comparing pudendal block to sham¹⁷ A small study of patients undergoing colporrhaphy was found to have slightly lower VAS pain scores, lower analgesic consumption (tramadol + ketoprofen), quicker return to regular activity, & great satisfaction, compared to a sham block¹⁶
Paracervical block	Blocks sympathetic, parasympathetic, & visceral sensory signals from the upper vagina, cervix, & lower uterus	Meta-analysis of 3 RCTs evaluating paracervical block for laparoscopic hysterectomy found a significant reduction in VAS pain scores and opioid requirement but no changes in LOS¹⁸
Epidural	Blocks sympathetic, parasympathetic, & visceral sensory signals in a dermatomal fashion.	Open procedures: A systematic review of RCTs of open abdominal surgery (colorectal, hepatic, aortic; no gynecologic surgery included) reported superior pain control in the epidural group & quicker return of bowel function, but no significant differences in LOS, compared to PCA or wound infiltration^a Laparoscopic procedures: A systematic review demonstrated superior pain control in the epidural group in laparoscopic colorectal surgery. No significant differences were found among groups in LOS^b Overall: Comparison of epidural vs TAP blocks for patients undergoing abdominal surgery (colorectal, gynecologic, urologic, open & laparoscopic) showed in a multicenter RCT similar pain scores, but lower opioid consumption in the epidural group (60% less than TAP group). There was no significant difference in LOS or opioid-related complications^c Meta-analysis showed epidural analgesia, compared to TAP blocks, decreased pain scores & opioid requirement²¹
Level of CNS
Opioid analgesics	Interact with μ-, ∂-, κ-, γ-receptors	Multimodal analgesia to minimize opioids due to their side-effects (nausea, vomiting, ileus, respiratory depression, & risk of dependence & abuse) per ERAS protocol¹
Nonopioid analgesics	—	Acetaminophen, dexamethasone, anticonvulsants, & ketorolac have positive opioid-sparing effects & are recommended per ERAS protocol¹
General anesthesia	Suppression of central processing (loss of consciousness)	General anesthesia accomplishes loss of consciousness to where noxious stimuli do not get interpreted by the brain as pain; sympathetic response & inflammation are not blocked by general anesthesia but could be reduced by adjuncts, such as steroids, lidocaine, and ß-blockade.

Hughes MJ, Ventham NT, McNally S, et al. Analgesia after open abdominal surgery in the setting of enhanced recovery surgery: A systematic review and meta-analysis. JAMA Surg 2014;149(12):1224–1230; doi: 10.1001/jamasurg.2014.210

Levy BF, Tilney HS, Dowson HM, et al. A systematic review of postoperative analgesia following laparoscopic colorectal surgery. Colorectal Dis 2010;12(1):5–15; doi: 10.1111/j.1463-1318.2009.01799.x

Turan A, Cohen B, Elsharkawy H, et al. Transversus abdominis plane block with liposomal bupivacaine versus continuous epidural analgesia for major abdominal surgery: The EXPLANE randomized trial. J Clin Anesth 2022;77:110640; doi: 10.1016/j.jclinane.2021.110640

hr(s), hour(s); LOS, length of stay; SHP, superior hypogastric plexus; RCT, randomized controlled trial; TAP, transversus abdominis plane; VAS, visual analogue scale; MED, morphine-equivalent dose; QLB, quadratus lumborum block; TAH, total abdominal hysterectomy; ESP, erector spinae plane; PCA, patient-controlled analgesia; CNS, central nervous system; ERAS, enhanced recovery after surgery.

Local Anesthetic

One of the most-accessible adjunct modalities of surgical pain control is the administration of local anesthetic (LA) at the incision. LA blocks the nociceptive signal at its origin and is recommended as a part of ERAS protocols.¹ The surgeon's use of local incision infiltration in combination with nonsteroidal anti-inflammatory drugs (NSAIDs) can result in reduced morphine consumption during the early hours following surgery.²

Intraperitoneal (i.p.) LA infusion is another modality for blocking the nociceptive signal close to its origin. A systematic review by Marchand et al. showed a small reduction in pain scores with i.p. bupivacaine infusion versus placebo in 8 clinical trials on laparoscopic gynecologic surgery.³

The ERAS guidelines incorporate perioperative intravenous (i.v.) lidocaine infusions as part of a multimodal approach to pain management. In a study by Taiym et al., the researchers showed a significant reduction in opioid consumption by patients receiving lidocaine infusions post planned laparotomy for oncologic surgery.⁴ However, overall literature on the efficacy of lidocaine infusions is very heterogeneous, making meta-analysis comparison impossible because of differences in dosing, duration, and types of procedures.⁵ Furthermore, because of the potential for severe complications associated with inappropriate dosing, the most-recent guideline from the Royal College of Anaesthetists supported by the European Society of Regional Anaesthesia recommends lidocaine infusions only for selected patients with appropriate monitoring.⁶

Anti-Inflammatory Agents

Anti-inflammatory agents also target the nociceptive signal at its origin by reducing inflammation at the site of the surgery. NSAIDs are recommended as a part of ERAS protocols.¹ NSAIDs overall have a low rate of side-effects, but dosing needs to account for renal function. Interestingly, lidocaine also has shown an anti-inflammatory effect in the reduction of inflammatory markers.⁶

Autonomic System Nerve Block

The visceral sensory pain signals originating from the pelvis are transmitted through different pathways, including the para-aortic ganglia, hypogastric plexus, or presacral nerves. Attempts to block acute visceral postsurgical pain have not been as promising. The largest randomized controlled trial (RCT) did not significantly reduce pain scores or morphine-equivalent doses (MEDs) for patients undergoing laparoscopic surgery.⁷

Transverse Abdominis Plane Block

The most-common nerve block for gynecologic surgery is the transverse abdominis plane (TAP) block because of its technical ease and low-risk profile. TAP blocks hinder the transmission of nociceptive sensation to the anterior and lateral abdominal wall and parietal peritoneum, providing somatic but not visceral coverage. TAP blocks, in the form of single-shot and continuous-infusion catheters, have been extensively used in gynecologic surgeries; however, evidence is mixed on their effectiveness for pain control.

Initially, in 2016, Brogi et al. published a large systematic review and meta-analysis of 51 RCTs that compared TAP blocks to placebo. The researchers found that TAP blocks reduced the patients' visual analogue (VAS) pain scores at 6 hours by 1.4 points (of 10), at 12 hours by 2.0, and at 24 hours by 1.2. Similarly, compared to placebo, TAP blocks reduced morphine consumption 24 hours after surgery.⁸ Both open and laparoscopic procedures were included in this analysis.

Yet, an updated systematic review and meta-analysis by Shin et al. in 2020 comparing TAP blocks to a control group for laparoscopic and robotic hysterectomies showed no significant improvement in VAS pain scores at 24 hours post operation and no reduction in 24-hour opioid use.⁹ The likely explanations for the discrepancies in these studies are the difference in the technique (open versus minimally invasive) and the rise of ERAS protocols with increased utilization of multimodal systemic agents, decreasing the impact of TAP blocks alone.

Furthermore, a recent prospective double-blinded RCT (2023) by Bernard et al. of surgeon-administered TAP blocks for 79 patients undergoing open gynecologic surgery compared TAP blocks to placebo, and this RCT showed no significant reduction in opioid consumption, time-to-bowel function, and length of stay among patients who had midline laparotomy.¹⁰ The researchers concluded that a surgeon-performed TAP block “should not be considered standard of care in postoperative multimodal analgesia.”¹⁰ This may be caused by a landmark approach or laparoscopic guidance lacking the final confirmation that the local anesthetic is placed in the correct fascial plane.

Interestingly, another RCT published in the same year involved 80 patients undergoing open gynecologic surgery. This study compared experienced anesthesiologist–administered TAP blocks to a saline placebo in a setting of all patients receiving multimodal analgesia (dexamethasone, acetaminophen, flurbiprofen, and celecoxib). The researchers found a small but statistically significant reduction in pain scores and opioid requirements.¹¹

Of note, it is well-known that laparoscopic techniques are associated with less pain, compared to open abdominal procedures; thus, open approaches have entirely different pain-control needs. Based on the current evidence, TAP blocks do not provide additional benefits for patients undergoing gynecologic surgery via minimally invasive approaches in the context of robust multimodal analgesics. Patients undergoing open procedures may benefit from TAP blocks if no other blocks (including epidural) are available or germane.

Paravertebral Block

Paravertebral blocks (PVBs) target similar pain generators as do TAP blocks. However, because PVBs are done more proximally, they result in numbness of the chest and abdominal wall in a dermatomal fashion based on the specific level of injection. Melnikov et al. analyzed data of 58 patients in a prospective, randomized, controlled, observer-blinded study to compare the effectiveness of TAP block versus PVB among women undergoing major gynecologic surgery.¹² The researchers found that both blocks were associated with significant reductions in opioid consumption and pain scores compared to the control group. The PVBs are technically more challenging, even with ultrasound guidance, and pose an increased risk of pneumothorax, hypotension from sympathectomy, and possible epidural spread.

Quadratus Lumborum Block

The quadratus lumborum block (QLB) is a fascial-plane block that anesthetizes nerves that provide sensory and some visceral coverage to the anterior and lateral abdominal wall. A 2022 systematic review and meta-analysis examined 36 RCTs for open total abdominal hysterectomies (TAHs). The researchers reported that the QLB prolonged time to the first analgesia requests and significantly improved resting pain scores.¹³

Erector Spinae Plane Block

The erector spinae plane (ESP) block involves injection of LA deep into the erector spinae muscle overlying the transverse process of the spine. In a 2022 study by Warner et al. comparing ESP and TAP blocks for laparoscopic hysterectomy, the researchers showed no additional benefits for reducing pain scores or opioid consumption, therefore concluding that there are no additional analgesic benefits of using the ESP block.¹⁴

Rectus-Sheath Block

The rectus-sheath block is another regional technique that can be used for gynecologic surgeries with midline incisions. Bakshi et al. placed bilateral rectus-sheath catheters in 74 female patients undergoing gynecologic oncology surgeries with midline laparotomies under general anesthesia.¹⁵ At 24 hours, patients randomized to receive an infusion of LA had lower morphine consumption, compared to a group of patients who had received normal saline. The researchers also found a significant reduction in opioid-related side-effects at 48 hours in the LA-infusion group. The researchers concluded that intermittent LA boluses through rectus-sheath catheters provided effective morphine-sparing pain management.

Paracervical and/or Pudendal Nerve Block

Surgery in the lower pelvis and pelvic floor warrants a separate set of blocks because of different innervation pathways. The obstetrician or gynecologist may perform a paracervical and/or pudendal nerve block, which is frequently a 1-time injection of LA adjacent to the sacral plexus. The duration and density of the block depend on the dose, concentration, and pharmacology of the LA of choice. A small study of patients undergoing colporrhaphy showed the potential benefit of a pudendal block with slightly lower VAS pain scores, lower analgesic consumption, and quicker return to activity, compared to a sham block.¹⁶ However, an RCT of women undergoing pelvic reconstruction found no difference in pain scores; opioid consumption was lower but not significantly when comparing pudendal block versus sham.¹⁷

The paracervical block can also be used for patients undergoing gynecologic procedures involving cervical dilation and uterine intervention. Meta-analysis of 3 RTCs evaluating paracervical block for laparoscopic hysterectomy found a significant reduction in VAS pain scores and opioid requirements but no change in length of stay.¹⁸

Neuraxial Anesthesia

One of the oldest regional anesthesia modalities is neuraxial anesthesia. Neuraxial techniques for gynecologic surgery can be used as a primary anesthetic or in combination with general anesthesia. These blocks can range from intrathecal opioids to epidural catheters. Intrathecal opioids, in combination with general anesthesia, can reduce postoperative opioid consumption. Hein et al. reported that intrathecal morphine supplementation among women undergoing abdominal hysterectomy under general anesthesia significantly reduced the first 24-hour patient-controlled morphine consumption.¹⁹

In a meta-analysis by Wu et al. comparing epidural analgesia versus i.v. patient-controlled analgesia with opioids, they reported that an epidural provided superior postoperative analgesia compared to i.v. opioids.²⁰ In a systematic review of TAP blocks versus epidural catheters for abdominal surgeries, Desai et al. found epidural analgesia to be statistically superior to TAP blocks for postoperative pain scores at rest, i.v. morphine-equivalent consumption at an 0- to 24-hour interval, and time to first ambulation.²¹ While neuraxial anesthesia techniques can be effective, patient refusal, altered coagulation profile, improper discontinuation of anticoagulant medication, and spine deformities may warrant exploring alternatives, such as peripheral nerve blocks, for postoperative pain control.

Opioid and Multimodal Analgesics

Opioids have long been a mainstay of pain control since the first use of morphine in the early nineteenth century. Opioid analgesics have systemic effects through their interaction with μ-, ∂-, κ-, and γ-receptors and thus also result in undesirable side-effects such as nausea, emesis, ileus, and respiratory depression. ERAS protocols lean on utilization of multimodal analgesia to minimize the disagreeable side-effects of opioids. Examples of medications that can facilitate the reduction of opioid requirements include acetaminophen, NSAIDs, dexamethasone, anticonvulsants, n-methyl-d-aspartate (NMDA) receptor antagonists, and α-2 receptor agonists. The benefits of acetaminophen and NSAIDs are well-known and recommended by ERAS protocols.¹.

Ketamine has an established history as an analgesic. A 2021 meta-analysis by Wang et al. showed a reduction in opioid consumption at 4 and 12 hours after surgery and no significant difference at 24 and 48 hours; however, these findings have to be interpreted cautiously because of the high degree of heterogeneity among the studies.²² Clinicians also must consider the risk of psychotomimetic symptoms associated with ketamine. Consensus guidelines by the American Society of Regional Anesthesia and Pain Medicine recommend careful patient selection and subanesthetic doses (up to 1 mg/kg per hour).²³

Another NMDA agonist is magnesium, which can be used as an adjunct in pain control. A meta-analysis by De Oliveira et al. in 2013 showed a reduction in pain scores and opioid consumption; however, those results need to be interpreted very cautiously because of the very high level of heterogeneity among the studies.²⁴ Furthermore, with the widespread implementation of ERAS in the past decade, the effectiveness and role of magnesium are yet to be determined, and, at this time, no updated meta-analysis has been performed.

Dexmedetomidine is an α-2 receptor agonist that has been used in pain control. A Cochrane Review in 2016 reviewed 7 studies involving 492 participants and found low-quality evidence that i.v. morphine-equivalent consumption was reduced with dexmedetomidine at 4 and 24 hours after surgery.²⁵ Similarly, the quality of evidence was low for reduction of pain scores at 4, 6, 12, and 24 hours after surgery, and this reduction was not clinically significant.²⁵ Meta-analysis was not possible because of the substantially high heterogeneity of the studies.

Conclusions

For an optimal pain-control plan, multimodal analgesics need to be considered according to each case together with their side-effects to achieve the best combination for specific patient needs.

Pain after gynecologic surgery is common, especially with large abdominal incisions and extensive tissue manipulation. Optimal pain management should be considered in all phases of perioperative care (see Fig. 1) —more specifically, preemptive treatment with oral multimodal analgesics as a part of an ERAS protocol and postoperative pain management that facilitates return to function. Long-term recovery should focus on the restoration of quality of life.

FIG. 1.

Phases of perioperative care and pain control. pre-op, pre-operation; ERAS, Enhanced Recovery After Surgery.

An ideal pain-management plan uses multiple modalities of analgesics, targeting pain relief from the distal nerve endings to the pain-processing center in the brain (see Table 1). The benefits of systemic anti-inflammatory agents targeting the pain signal's transduction have been well-demonstrated and widely accepted as part of ERAS protocols. Successful blockade of pain signals through the peripheral and central nervous system hinges on selecting an appropriate target location and the extent of surgical manipulation.

Postoperative pain management should reduce or eliminate the need for opioids with minimal interference with mobilization, enteral intake, and other avenues of enhanced recovery. While no regional-block technique is superior for patients undergoing all types of gynecologic surgery, it is recommended that regional anesthesia should be offered to provide effective acute postsurgical pain relief. Pain management is an interdisciplinary effort in which the collaborating teams select specific modalities to maximize benefits and minimize side-effects specific to the patients and types of surgery.

Footnotes

Acknowledgments

The authors thank Gerard Hebert, MA, for editorial assistance through the Moffitt Cancer Center's Office of Scientific Publishing.

Authors' Contributions

Dr. Jones conceptualized and visualized the study, conducted a literature review with Ms. Quach and Dr. Tanios, and curated the data. All of the authors participated in the writing and editing of the original draft of this article. Dr. Jones worked on manuscript revisions.

Author Disclosure Statement

No financial conflicts of interest exist.

Funding Information

There was no funding for this research and writing.

References

Nelson

, Bakkum-Gamez

, Kalogera

, et al. Guidelines for perioperative care in gynecologic/oncology: Enhanced Recovery After Surgery (ERAS) Society recommendations—2019 update. Int J Gynecol Cancer, 2019; 29(4):651–668; doi: 10.1136/ijgc-2019-000356

Bamigboye

, Hofmeyr

. Local anaesthetic wound infiltration and abdominal nerves block during caesarean section for postoperative pain relief. Cochrane Database Syst Rev, 2009; 3:CD006954; doi: 10.1002/14651858.CD006954.pub2.

Marchand

, Ware

, Govindan

, et al. A Systematic review and meta-analysis of intraperitoneal bupivacaine in laparoscopic gynecologic surgery. J Pain Res, 2021; 14:2699–2707; doi: 10.2147/JPR.S326145

Taiym

, Cowan

, Nakamura

, et al. Effect of continuous post-operative lidocaine infusion in an enhanced recovery program on opioid use following gynecologic oncology surgery. J Gynecol Oncol, 2023; 34(5):e61; doi: 10.3802/jgo.2023.34.e61

Weibel

, Jelting

, Pace

, et al. Continuous intravenous perioperative lidocaine infusion for postoperative pain and recovery in adults. Cochrane Database Syst Rev, 2018; 6:CD009642; doi: 10.1002/14651858.CD009642.pub3

Foo

, Macfarlane

AJR

, Srivastava

, et al. The use of intravenous lidocaine for postoperative pain and recovery: International consensus statement on efficacy and safety. Anaesthesia, 2021; 76(2):238–250; doi: 10.1111/anae.15270

Clark

, Moore

, Maghsoudlou

, et al. Superior hypogastric plexus block to reduce pain after laparoscopic hysterectomy: A randomized controlled trial. Obstet Gynecol, 2021; 137(4):648–656; doi: 10.1097/AOG.0000000000004329

Brogi

, Kazan

, Cyr

, et al. Transversus abdominal plane block for postoperative analgesia: A systematic review and meta-analysis of randomized-controlled trials. Can J Anaesth, 2016; 63(10):1184–1196; doi: 10.1007/s12630-016-0679-x

Shin

, Balk

, Gritsenko

, et al. Transversus abdominis plane block for laparoscopic hysterectomy pain: A meta-analysis. JSLS, 2020; 24(2):e2020.00018; doi: 10.4293/JSLS.2020.00018

10.

Bernard

, Lavecchia

, Trepanier

, et al. A double-blinded, randomized trial comparing surgeon-administered transversus abdominis plane block with placebo after midline laparotomy in gynecologic oncology surgery. Am J Obstet Gynecol, 2023; 228(5):553e1–551e8; doi: 10.1016/j.ajog.2023.02.010

11.

Geng

, Zhang

, Bi

, et al. Addition of preoperative transversus abdominis plane block to multimodal analgesia in open gynecological surgery: A randomized controlled trial. BMC Anesthesiol, 2023; 23(1):21; doi: 10.1186/s12871-023-01981-w

12.

Melnikov

, Bjoergo

, Kongsgaard

. Thoracic paravertebral block versus transversus abdominis plane block in major gynecological surgery: A prospective, randomized, controlled, observer-blinded study. Local Reg Anesth, 2012; 5:55–61; doi: 10.2147/LRA.S35858

13.

Tsai

M-C

, Bai

G-H

, Hung

T-Y

, et al. Comparison of the efficacy of single-injection regional analgesia techniques for total abdominal hysterectomy: A systematic review and network meta-analysis. Pain Physician, 2022; 25(8):543–553.

14.

Warner

, Yeap

, Rigueiro

, et al. Erector spinae plane block versus transversus abdominis plane block in laparoscopic hysterectomy. Pain Manag, 2022; 12(8):907–916; doi: 10.2217/pmt-2022-0037

15.

Bakshi

, Mapari

, Shylasree

. REctus Sheath block for postoperative analgesia in gynecological ONcology Surgery (RESONS): A randomized-controlled trial. Can J Anaesth, 2016; 63(12):1335–1344; doi: 10.1007/s12630-016-0732-9

16.

Khalil

, Itani

, Naja

, et al. Nerve stimulator–guided pudendal nerve block vs general anesthesia for postoperative pain management after anterior and posterior vaginal wall repair: A prospective randomized trial. J Clin Anesth, 2016; 34:668–675; doi: 10.1016/j.jclinane.2016.07.024

17.

Slopnick

, Sears

, Chapman

, et al. Pudendal nerve block analgesia at the time of vaginal surgery: A randomized, double-blinded, sham-controlled trial. Urogynecology (Phila), 2023; 29(10):827–835; doi: 10.1097/SPV.0000000000001351

18.

Badran

, Abdelhakim

, Labib

, et al. Role of paracervical block in reducing postoperative pain after laparoscopic hysterectomy: A systematic reivew and meta-analysis of randomized controlled trials. J Gynecol Obstet Hum Reprod, 2021; 50(9):102156; doi: 10.1016/j.jogoh.2021.102156

19.

Hein

, Rosblad

, Gillis-Haegerstrand

, et al. Low dose intrathecal morphine effects on post-hysterectomy pain: A randomized placebo-controlled study. Acta Anaesthesiol Scand, 2012; 56(1):102–109; doi: 10.1111/j.1399-6576.2011.02574.x.

20.

, Cohen

, Richman

, et al. Efficacy of postoperative patient-controlled and continuous infusion epidural analgesia versus intravenous patient-controlled analgesia with opioids: A meta-analysis. Anesthesiology, 2005; 103(5):1079–1088; quiz: 109–110; doi: 10.1097/00000542-200511000-00023

21.

Desai

, El-Boghdadly

, Albrecht

. Epidural vs. transversus abdominis plane block for abdominal surgery—a systematic review, meta-analysis and trial sequential analysis. Anaesthesia, 2021; 76(1):101–117; doi: 10.1111/anae.15068

22.

Wang

, Lin

, Lan

, et al. Perioperative intravenous S-ketamine for acute postoperative pain in adults: A systematic review and meta-analysis. J Clin Anesth, 2021; 68:110071; doi: 10.1016/j.jclinane.2020.110071

23.

Schwenk

, Viscusi

, Buvanendran

, et al. Consensus guidelines on the use of intravenous ketamine infusions for acute pain management from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists. Reg Anesth Pain Med, 2018; 43(5):456–466; doi: 10.1097/AAP.0000000000000806

24.

De Oliveira

Jr , Castro-Alves

, Khan

, et al. Perioperative systemic magnesium to minimize postoperative pain: A meta-analysis of randomized controlled trials. Anesthesiology, 2013; 119(1):178–190; doi: 10.1097/ALN.0b013e318297630d

25.

Jessen Lundorf

, Korvenius Nedergaard

, Moller

. Perioperative dexmedetomidine for acute pain after abdominal surgery in adults. Cochrane Database Syst Rev, 2016; 2:CD010358; doi:10.1002/14651858.CD010358.pub2