INTERFASCIAL PLANE BLOCKS IN OBSTETRIC AND GYNECOLOGIC SURGERY

Abstract

Introduction

Interfascial plane blocks (IPB) are truncal blocks with local anesthetic injected into space between two muscle layers. IPBs are easy to learn, simple to perform, provide satisfactory analgesia up to 24 hours, having a minimal risk of complications.

Methods

We present a retrospective analysis of the patients who had IPB as a part of postoperative pain management plan following either CD or hysterectomy in Leskovac General Hospital, Serbia during the period April 2017 – February 2022.

Results

We had 131 patients who had IPB perioperatively. Bilateral QLB type 1 was performed in 53 patients after CD and in 68 patients after hysterectomy. Bilateral ESPB T10-11 was done following one CD case and in 9 patients before hysterectomy. Patients had both acetaminophen and nonsteroidal anti-inflammatory drug for postoperative pain control. Decreased usage of fentanyl and sevoflurane was noticed in the cases where IPB was performed preoperatively. Almost all patients had well-controlled pain, and were very satisfied with pain score of 0-4/10 at numeric rating scale during 24 hours after surgery, with no opioid use. There were no complications regarding block performance.

Conclusion

QLB and ESPB have great potential to improve and facilitate postoperative pain management in obstetric and gynecologic surgery.

Introduction

Regional anesthesia/analgesia (RA) techniques are integral to a preemptive analgesia strategy. These techniques prevent the development of persistent postoperative pain. (1) The current guidelines for postoperative nausea and vomiting prophylaxis and treatment (2) also support the usage of RA techniques. Neuraxial anesthesia/analgesia (NA), paravertebral block, peripheral nerve blocks, or interfascial plane blocks (IPB), all support an opioid minimizing approach. NAtechniques are known as the gold standard procedures that provide surgical anesthesia and postoperative analgesia for various surgeries. However, a growing number of patients on anticoagulant therapy limits the use of both NA and paravertebral block in everyday clinical practice. These situations influence the development of alternative analgesic solutions such as IPBs. IPBs are local anesthetic injections into interfacial plane routinely performed under ultrasound guidance. IPBs have become a part of useful skills/tools in a growing number of anesthesiologists. IPBs are truncal blocks with local anesthetic injected into space between two muscle layers. IPBs are easy to learn, simple to perform, provide satisfactory analgesia up to 24 hours, having a minimal risk of complications. (3)

The quadratus lumborum block (QLB) (4) and the erector spinae plane block (ESPB) (5) are newly developed ultrasound-guided IPBs that provide good postoperative analgesia following Cesarean delivery (CD) (6-12) and gynecologic procedures. (6, 7, 11, 12) They were not a part of clinical practice in Serbia before April 2017, when QLB was introduced in Leskovac General Hospital (LGH) thanks to the international teaching Kybele Inc. program. (13, 14)Their use had started as a part of perioperative multimodal pain management following general surgery cases in adults. (13) Furthermore, QLB and ESPB were included in pain treatment in CD, hysterectomy, urologic, and orthopedic cases, and also in pediatric patients. (15)

Methods

We present a retrospective analysis of the patients who had IPB as a part of postoperative pain management plan following either CD or hysterectomy in LGH during the period April 2017 – February 2022. All CD and hysterectomy cases utilizing either QLB or ESPB were obtained from the anesthesia databases of LGH.

Results:

We had 131 patients who had IPB perioperatively (table 1). Bilateral QLB type 1 was performed in 53 patients after CD. Thirty seven cases were done under general anesthesia (GA), and 16 cases were done under spinal anesthesia (SA). Bilateral QLB type 1 was also performed in 68 patients after hysterectomy (63 cases done under GA, 5 cases done under SA). Bilateral ESPB T10-11 was done following one CD case and in 9 patients before hysterectomy (all cases done under GA). IPBs were performed either in the operating room (before the surgery, or at the end of the surgery during emergence from GA) or in the intensive care unit after recovery from spinal anesthesia.

Table 1. Demographic and clinical data.

Procedure	Anesthesia	Patients			QLB	ESPB
		Number	Age#	ASA II /ASAIII
Hysterectomy	GA	72	51.1	60 / 12	63	9
	SA	5	47.4	4 / 1	5	0
Cesarean Delivery	GA	38	28.7	29 / 9	37	1
	SA	16	27.4	4 / 12	16	0
In total		131	42.4	97 / 34	121	10

GA – general anesthesia; SA – spinal anesthesia; QLB – quadratus lumborum block; ESPB – erector spinae plane block; # mean.

All patients that had IPB were checked for pain relief immediately after surgery and at several intervals during the first 24 hours postoperatively.

Parturients were healthy, 20 to 40 years old, with no previous medical history. Some of them had in vitro fertilization (IVF) and lowmolecularweightheparin (LMWH) in prophylactic regiment. One of the parturients had IVF, prophylactic regiment of LMWH and preeclampsia with severe features. Since a dose of LMWH has been given 5 hours before urgent CD was indicated, surgery was done under GA. She had ESPB postoperatively in the intensive care unit as a rescue analgesic treatment.

The patients who had hysterectomy were 29 to 84 years old. They were ASA status II or III.

The majority of both CD cases (38/54) and hysterectomy cases (72/77) were done under GA. Anesthesia induction was done using propofol 1.5-2.5 mg/kg. Fentanyl 1-2 mcg/kg was given at induction, and repeated if needed. In CD cases fentanyl was started after childbirth. Sevoflurane in a 50% air / 50% oxygen mixture with an end-tidal of 1-2 vol% was used as the maintenance agent. Rocuronium was used in intubation dose of 0.6 mg/kg and repeated if necessary to maintain a paralysis.

The rest of the cases (16/54 CD and 5/77 hysterectomy) were done under SA provided using 12.5 mg of 0.5% bupivacaine or levobupivacaine in combination with 20 mcg of fentanyl.

Patients had both acetaminophen and nonsteroidal anti-inflammatory drug (NSAID) for postoperative pain control around a clock. The first dose was injected during the last 30 minutes of surgery done under GA or postoperatively, after recovery from SA. All patients had acetaminophen at dose of 1 g Q6H or Q8H. The other analgesic was ketorolac (30 mg Q6H or Q8H), ketoprofen (100 mg Q6H or Q8H), or metamizole (2.5 g Q12H or Q8H). Tramadol was available as a rescue analgesic.

QLB was done after surgery, during emergence from GA (110 patients), or after recovery from SA (21 patients). ESPB was done preoperatively, before induction of GA in 9 hysterectomy cases. One CD case had ESPB performed after surgery in the ICU. We used 0.25% bupivacaine or levobupivacaine at dose of 20 ml per side for ESPB or 30 ml per side for QLB. All patients had bilateral blocks, so they had 40 or 60 ml of local anesthetic solution in total. Everyone had 4 mg dexamethasone in injected solution. We also used 22-gauge 50, 100 or 150 mm needles for the peripheral nerve block, and the linear ultrasound probe as a guidance.

Decreased usage of fentanyl and sevoflurane was noticed in the cases where IPB was performed preoperatively.

Almost all patients (128/131) had well-controlled pain, and were very satisfied with pain score of 0-4/10 at numeric rating scale (NRS) during 24 hours after surgery, with no opioid use. Only 3 patients (that had QLB after hysterectomy) requested for more analgesics, and needed opioids postoperatively.

There were no complications regarding block performance.

Discussion

QLB is a posterior abdominal wall block that is performed by injecting local anesthetic into the interfascial plane around quadratus lumborum muscle. Although Akerman et al. describe clear sonographic landmarks that allow QLB to be easily performed, (7) El-Boghdadly et al. see QLB as a time-consuming, advanced block that is technically challenging to perform.¹⁶However, both groups of authors agree that QLB is less invasive, safer and quicker alternative to the epidural technique. We believe that “easiness” of QLB performance depends on the type of QLB that is chosen. At least for our service, QLB type 1 and 2 are easier to perform than QLB type 3.

ESPB was described as a local anesthetic injection into the interfascial plane between the erector spinae muscle (ESM) and transverse process of the vertebra.⁵Depending on the site of local anesthetic injection, ESPB can provide analgesia in the cervical, thoracic, abdominal and lumbar regions. Local anesthetic injection at the level of thoracic vertebra T9-11 will provide satisfying perioperative analgesia following CD and gynecologic surgery. (11)

The mechanism of action of IPBs is still not clear. Radiological imaging in cadavers and live patients confirms that injectate (after both QLB and ESPB performance) spreads extensively in the fascial sheath around the ESM, epidural and paravertebral space resulting in parietal and visceral analgesia. (16-20) Chin et al. suggest that an increased likelihood of local anesthetic penetration to the paravertebral space could be provided by injecting closer to the neuraxial mid-line, choosing ESPB instead of QLB whenever it is possible, and depositing local anesthetic deep to the ESM.²¹Our service prefers ESPB over QLB, except in situations when the patient has to stay in the supine position or has too much pain to turn to lateral or prone position. They also emphasize that intramuscular injection should be avoided by confirming local anesthetic spread between two distinct hyperechoic layers under ultrasound.

QLB attracted anesthesiologists by its great analgesic potential in post-Cesarean pain treatment that Blanco et al. had shown. (21-23) Many randomized controlled trials (RCT), meta-analyses, and trial sequential analyses (TSA) have shown QLB benefits in CD. (8-10, 22-28)

A working Group of the European Society of Regional Anaesthesia and Pain Therapy (ESRA) and a working group of the Society for Obstetric Anesthesia and Perinatology (SOAP) published their recommendations for perioperative pain management after CD at the same time (May 2021). Both groups included QLB in their recommendations. It was suggested that multimodal perioperative pain management should be based on intrathecal (or epidural) long-acting opioid (usually morphine) supplemented by scheduled paracetamol and NSAID use. Analgesics should be started in the operating room, before the onset of pain and not upon first pain request. Truncal wall block (the transversus abdominis plane (TAP) or QL) should be provided if neuraxial morphine cannot be given, or as a rescue technique when severe breakthrough pain develops despite the use of neuraxial morphine. (29, 30)

TAP block was the first IPB used as postoperative analgesic tool following gynecologic procedures and CD. According to many studies, TAP block has analgesic benefits compared to placebo. However, new data suggest no analgesic benefits if TAP block was used as a part of multimodal postoperative pain management. The TAP block added to combination of paracetamol and NSAID does not improve pain control compared to effects provided by combination of paracetamol and NSAID alone. (31, 32)

QLB significantly reduces perioperative opioid use after CD, (8, 22-24, 26-28, 33) laparoscopic hysterectomy (LH), (34-36)and total abdominal hysterectomy (TAH), (37, 38) and consequently a frequency of postoperative nausea and vomiting. (35) QLB as a part of multimodal pain management, given in combination with paracetamol and NSAID, also prolongs time to first request for breakthrough pain following CD, (8, 22-24, 27, 33) LH, (34, 35, 39) and TAH. (38) QLB provides larger filed of analgesia and more lasting analgesia (up to 24-36 hours) compering to TAP block (up to 10 hours) after CD, (23, 27, 28, 33) LH (34, 39, 40) and TAH, (37, 38) decreasing a number of breakthrough pain requests. Having a skin injection point more lateral of surgical incision than TAP block, QLB minimizes a risk for surgical site contamination. QLB significantly reduces a risk of local anesthetic systemic toxicity (LAST) comparing to TAP block. (34) However; El-Boghdadly et al. (27) concluded in their meta-analysis that QLB was not significantly superior to TAP in multimodal analgesia management after CD. Almost all authors agree that clinical utility of both QLB and TAP block seems limited to situations in which intrathecal morphine is not used. (10, 25, 27)

RCT had shown that QLB, as a component of multimodal post-caesarean section analgesia, was associated with lower 24-h opioid consumption and longer time to first analgesic request compared to wound infiltration effects.⁴⁰Mieszkowski M et al. show that patients who had QLB in multimodal postoperative management plan were more satisfied than patients who had only paracetamol and NSAID. They also show a tendency for a lower incidence of chronic pain when QLB was provided. (41)

Contrary to abundance of data for QLB use in obstetric and gynecologic surgery, there are only few RCTs and several case series on the use of ESPB for these cases. RCTs showed that ESPB added to paracetamol and NSAID in multimodal perioperative pain management had significant analgesic effects reducing both opioid use and postoperative pain score after CD (42, 43) and TAH. (44, 45) Furthermore, comparative RCTs shows that ESPB induces more effective pain relief, longer lasting analgesia, and longer time to first rescue analgesic request than TAP block. (42, 43, 45, 46)

We did not have any IPB-related complications. The complications associated with QLB and ESPB are quite rare. Since needle trajectory and point of injection are far away from peritoneal cavity, visceral abdominal organs, large vessels, and large nerves, QLB performance has not been associated with serious complications (unintentional peritoneal, bowel or kidney puncture). Using the transverse process as a target increases an ease and safety of ESPB performance. The right needle tip position is confirmed by the visual end-point as a linear spread of injectate in both a cranial and caudal direction from the point of injection. Despite of this Ueshima published unintentional pneumothorax during ESPB performance.⁴⁶Furthermore, the rules of ultrasound-guidance had to be followed. Mandatory monitoring of the needle tip prior to injecting the drug, and drug injection in aliquots of 3-5 ml after negative aspiration test under eye-control significantly increase the level of safety and efficiency of the technique. These rules also decrease a risk of LAST. LAST prophylaxis strategy also includes adequate local anesthetic dosing, adding epinephrine to local anesthetic solution, patient monitoring for 30-45 min after block performance, and “rescue kit” with checklist and 20% lipid emulsion available if LAST is developing. (47)

QLB and ESPB are likely safe in patients with coagulation disorders, and are associated with a much lower risk of nerve damage compared with epidural analgesia and paravertebral blocks. There are no data on neurological damage since the local anesthetic is not injected into the immediate proximity of the large nerve, but is injected into the space rich in small nerve endings. It is therefore generally accepted that QLB and ESPB can be performed both under general and regional anesthesia. (7)

An unwanted quadriceps weakness is cited as a possible complication of QLB 3 and low thoracic or lumbar ESPB. (48, 49) Having this in mind, a careful patient ambulation is advisable. We did not have any motor weakness although we did QLB and ESPB in almost 600 cases in LGH since 2017. However, we do not use QLB type 3, only QLB type 1 and 2.

Conclusion

QLB and ESPB have great potential to improve and facilitate postoperative pain management in obstetric and gynecologic surgery.