Combination of Bilateral Erector Spinae Plane Block and a Continuous Low-Dose Epidural Morphine Infusion for Perioperative Analgesia Following Major Lumbar Spine Surgery—A Case Series

Abstract

Pain management utilizing appropriate regional techniques is vital to enhance recovery following major spine surgery. Regional techniques are increasingly used for analgesia following major lumbar spine surgery. This preliminary study describes a combination of two regional techniques for perioperative analgesia following major lumbar spine surgery. Thirteen patients underwent lumbar decompressive surgery with fusion using a standard anesthesia technique. All patients received bilateral single-shot erector spinae plane block (ESPB) using ropivacaine with dexmedetomidine before the surgical incision for intraoperative analgesia and continuous low-dose epidural morphine via an intraoperatively placed epidural catheter at the end of surgery for postoperative analgesia. The total intraoperative fentanyl and morphine requirement was very low. The postoperative pain score (Numerical Rating Scale) ranged from 0 to 4 at various points during the first 48 hours after surgery. The mean ambulation time and duration of hospital stay were 2.07 ± 0.34 and 4.84 ± 2.07 days, respectively. Three out of 13 patients (23%) developed postoperative nausea and vomiting. The combination of bilateral single-shot ESPB and continuous low-dose epidural opioid infusion via an intraoperatively placed epidural catheter provides excellent perioperative analgesia for patients undergoing major lumbar spine surgery.

Keywords

epidural analgesia - erector spinae plane block - lumbar spine surgery - opioids - postoperative analgesia

Introduction

Pain after the major lumbar spine surgery is considered moderate to severe in intensity.[1] The intensity of pain negatively correlates with recovery. Patients often need potent opioids during the first 48 hours after surgery. Large doses of systemic morphine can increase opioid-related side effects and can delay recovery.[2] On the other hand, inadequate pain management delays ambulation, increases the incidence of deep venous thrombosis and respiratory complications, and can lead to chronic pain syndrome.[3]

Appropriate regional analgesia techniques have been utilized for lumbar spine surgery, which provides adequate analgesia while avoiding the use of large-dose systemic opioids and their side effects. Single-shot bilateral erector spinae plane block (ESPB) and thoracolumbar interfascial plane block are increasingly utilized to provide perioperative analgesia following lumbar spine surgery.[4] [5] [6] [7] The single-shot ESPB provides adequate intraoperative analgesia. The postoperative analgesia by single-shot ESPB lasts only 8 to 10 hours after major lumbar spine fusion surgery.[8] Epidural analgesia using local anesthetics via an intraoperatively placed epidural catheter is a feasible, safe, and cost-effective option for postoperative analgesia for 48 to 72 hours following major lumbar spine fusion surgery.[9] The combination of bilateral single-shot ESPB before the surgical incision and continuous epidural analgesia with low-dose morphine via an intraoperatively placed epidural catheter for perioperative analgesia for major lumbar spine surgery is not reported in the literature. This case series describes a combination of two regional analgesia techniques for perioperative analgesia following major lumbar spine surgery.

Case Series

The perioperative details of 13 patients who underwent one to two levels of decompression with transforaminal lumbar interbody fusion for degenerative disease of the lumbar spine (12 patients)/traumatic lumbar spine fracture (1 patient) were collected retrospectively after the institutional review board (IRB) approval (IRB-15023 dated November 23, 2022). As per the institutional protocol, all patients were explained in detail about anesthesia and perioperative analgesia plan during the preoperative visit, and informed consent was taken the day before surgery. The demographic data, diagnosis and surgical procedure, and the necessary intraoperative and postoperative data were collected.

Methods

In the operating room, after connecting the standard American Society of Anesthesiologists (ASA) monitors, all patients were induced with fentanyl (2 μg/kg) and propofol (2–3 mg/kg). Orotracheal intubation was performed with an appropriate-size endotracheal tube under atracurium (eight patients) or vecuronium (five patients). Eight patients received total intravenous anesthesia (TIVA) using propofol (80–100 µg/kg/min) and fentanyl infusion (0.5 µg/kg/h), titrated to BIS (Bispectral Index) of 40 to 60 for maintenance of anesthesia. The remaining five patients received air, oxygen, and sevoflurane (0.8–1 MAC) for maintenance (Sevoflurane). Neuromuscular blocking agent was deferred in patients receiving TIVA (8 patients). However, incremental doses of vecuronium were administered in patients (5 patients) receiving sevoflurane for maintenance of anesthesia. All the patients were catheterized to monitor urine output. Surgeons marked the levels of surgical instrumentation (two lumbar levels) using an image intensifier. An ultrasound-guided (2–5 MHz, curvilinear probe) bilateral ESPB was performed at two lumbar levels corresponding to the surgical marking. At each level, 10 to 12.5 mL of 0.3–0.375% ropivacaine was administered with a total volume of 40 to 50 mL (20–25 mL on each side). Twelve patients received dexmedetomidine (50 μg), and one patient received dexamethasone (8 mg) as an adjuvant. With the volume injected, we noted the drug spread both cranially and caudally to the adjacent levels (ultrasound confirmation). Baseline motor-evoked potential (MEP) responses were recorded for eight patients after transcranial electrical stimulation (electrode placement at C1/C2, according to the international 10–20 system). A train of four pulse stimulations with an intensity of 90 to 120 V, a pulse width of 300 to 400 milliseconds, and interstimulus interval of 3 ms was used to obtain the baseline MEP. Five lower limb muscles were monitored bilaterally, with the right or left thenar muscles serving as controls.

At the end of spinal fusion, after achieving hemostasis and ensuring that there is no cerebrospinal fluid (CSF) leak, the surgeon placed a 20G epidural catheter under direct vision via the cranial end of the laminectomy defect. Roughly 5 cm length of the catheter was inserted into the epidural space cranially. After ensuring the negative aspiration for CSF, 2 mL of 0.9% normal saline was injected to confirm the correct placement of an epidural catheter. While injecting the saline, the surgeon ensured that the saline did not appear in the surgical field and there was no resistance during the saline injection; both confirmed the correct placement of an epidural catheter. The epidural catheter was brought out separately and was fixed away from the surgical incision. All patients received 1 mg of epidural morphine except one who received 1.5 mg morphine as a bolus. After the surgical closure, patients were turned supine and extubated. For those who received intermittent doses of vecuronium (five patients—sevoflurane group), the residual relaxant effect was reversed with neostigmine (0.05 mg/kg) and glycopyrrolate (0.01 mg/kg). Those who received TIVA did not receive reversal agents. Soon after extubation, 7 mg morphine (7 mL) in 58 mL of 0.9% normal saline was loaded into the elastomeric pump (total volume: 65 mL) and was connected to the epidural catheter and started at 140 μg/h (1.3 mL/h) for 48 hours. All patients received intravenous paracetamol 650 to 1,000 mg every 6th hour and intramuscular ketorolac (30 mg) every 8th hour as part of the multimodal analgesia. The urinary catheter was removed on the second postoperative day. The epidural catheter was removed at the end of 48 hours.

Results

The mean age of patients was 48.54 ± 8.3 years (range: 33–63), and the body mass index was 27.77 ± 4.59 (range: 20–33) kg/m², with a male:female ratio of 6:7 and ASA-1:ASA-2 ratio 6:7. All patients presented with back pain with or without radiculopathy for varying durations, without any neurological deficits ([Table 1]).

Table 1 Demographics details, diagnosis, and surgery

Case No.	Age in years (mean ± SD)	Gender/ASA grade	BMI (Kg/m2) (Mean ± SD)	Diagnosis	Surgery
TIVA maintenance
1	40	F/2	29	L5–S1 listhesis	L5, S1 laminectomy and TLIF
2	63	M/1	25	L4–L5 listhesis	L4, L5 laminectomy and TLIF
3	52	F/1	33	L4–L5, L5–S1 listhesis	L4–S1 laminectomy and L4–L5 and L5–S1 TLIF
4	33	M/1	20	L4–L5 listhesis	L4, L5 laminectomy and TLIF
5	49	F/ 2	30	L5–S1 listhesis	L5, S1 laminectomy and TLIF
6	56	F/2	33	L4–L5 listhesis	L4–L5 laminectomy and TLIF
7	46	M/1	22	L2–l3 central disc bulge	L2–l3 laminectomy + TLIF
8	51	F/2	29	L3–L4, L4–L5 central disc bulge	L3–4, L4–5 laminectomy + L4–L4 TLIF
Sevoflurane maintenance
9	45	F/1	33	L4–5 listhesis	L4, L5 laminectomy and TLIF
10	42	M/1	23	L1 burst fracture	L1 laminectomy T10–L3 instrumentation
11	51	M/2	33	L2–L3 retrolisthesis	L2–L3 laminectomy and TLIF
12	43	M/2	25	L4–L5, L5–S1 central disc prolapse	L4– L5 laminectomy L4–S1 post-fixation + L5–S1 TLIF
13	60	F/2	26	L4–L5 listhesis	L4–L5 laminectomy + TLIF

Abbreviations: ASA, American Society of Anesthesiologists; BMI, body mass index; Dexmed, dexmedetomidine; F, female; M, male; SD, standard deviation; TIVA, total intravenous anesthesia; TLIF, transforaminal lumbar interbody fusion.

The mean dose of systemic fentanyl used for intraoperative analgesia was 3.77 ± 0.77 µg/kg. Seven patients did not receive systemic morphine, while the other six patients received a small dose (<0.05 mg/kg) during surgery. The mean blood loss was 654 ± 355 mL (range: 200–1,300 mL). The mean volume of crystalloid administration was 2,600 ± 537 mL. All patients except one received 500 mL of colloid (tetrastarch). Four out of 13 patients received 1 unit of packed red blood cells. The mean duration of anesthesia and surgery was 313 ± 68.4 and 239 ± 69 minutes, respectively. MEP monitoring was feasible in all eight patients who received TIVA and bilateral ESPB with 0.3 to 0.375% ropivacaine with dexmedetomidine. The intraoperative details were divided into those who received TIVA and sevoflurane maintenance, as depicted in [Table 2].

Table 2 Perioperative details

Case No.	Maintenance of anesthesia	Details of ESPB	Intraop fentanyl (ug/kg)/morphine (mg/kg)	PACU morphine (mg/kg)	Anesthesia duration (min)	Surgery duration (min)	Epidural analgesia morphine (bolus + infusion)	Time of oral fluid intake (h)	Time of ambulation (days)	Hospital stay, duration (days)	Post-op complications
TIVA maintenance
1	TIVA- propofol + fentanyl	40 mL of 0.375% Ropi + 50 µg Dexmed	3.9/0	0	240	180	1 mg bolus + 140 µg/h for 48 hours	5	2	4	Nil
2	TIVA- propofol + fentanyl	40 mL of 0.375% Ropi + 50 µg Dexmed	3.3/0	0	270	180	1 mg bolus + 140 µg/h for 48 hours	4	2.5	4	Nil
3	TIVA- propofol + fentanyl	40 mL of 0.3% Ropi + 50 µg Dexmed	3.4/0.04	0.0	360	300	1.5 mg bolus + 140 µg/h for 48 hours	3	2	6	Nil
4	TIVA- propofol + fentanyl	40 mL of 0.3% Ropi + 50 µg Dexmed	4.5/0.05	0	240	180	1 mg bolus + 140 µg/h for 48 hours	3	2	4	Nil
5	TIVA- propofol + fentanyl	40 mL of 0.3% Ropi + 50 µg Dexmed	4.7/0	0	240	180	1 mg bolus + 140 µg/h for 48 hours	2	2.5	4	Post-op vomiting treated with ondansetron
6	TIVA- propofol + fentanyl	40 mL of 0.3% Ropi + 50 µg Dexmed	4.4/0	0	300	240	1 mg bolus + 140 µg/h for 48 hours	2	2	11	Nil
7	TIVA- propofol + fentanyl	40 mL of 0.3% Ropi + 50 µg Dexmed	5/0.07	0.06	390	345	1 mg bolus + 140 µg/h for 48 hours	4	2.5	3	Nil
8	TIVA- propofol + fentanyl	40 mL of 0.3% Ropi + 50 µg Dexmed	3/0	0	440	330	1 mg bolus + 140 µg/h for 48 hours	5	2	4	Post-op vomiting treated with ondansetron
Sevoflurane maintenance
9	Air + O2 Sevo (0.8–1 MAC)	50 mL of 0.3% Ropi + Dexa 8 mg	3/0	0	270	180	1 mg bolus + 140 µg/h for 48 hours	2.5	1.5	5	Post-op vomiting treated with ondansetron
10	Air + O2 Sevo (0.8–1 MAC)	40 mL of 0.3% Ropi + 50 µg Dexmed	3.6/0	0	360	240	1 mg bolus + 130 µg/h for 8 hours	10	1.5	6	Nil
11	Air + O2 Sevo (0.8–1 MAC)	40 mL of 0.3% Ropi + 50 µg Dexmed	2.7/0.02	0	240	150	1 mg bolus + 140 µg/h for 48 hours	6	2.5	5	Nil
12	Air + O2 Sevo (0.8–1 MAC)	40 mL of 0.3%Ropi + 50 µg Dexmed	3.5/0.07	0.06	360	300	1 mg bolus + 75 µg/h + 0.06% Ropi for 18 hours	1	2	3	Right-sided foot drop managed conservatively resolved within 2 days
13	Air + O2 Sevo (0.8–1 MAC)	40 mL of 0.3% Ropi + 50 µg Dexmed	3.5/0.03	0.03	360	300	1 mg bolus + 140 µg/h for 48 hours	3	2	4	Nil

Abbreviations: Dexmed, dexmedetomidine; ESPB, erector spinae plane block; MAC, minimum alveolar concentration; PACU, post-anesthesia care unit; Ropi, ropivacaine; Sevo, sevoflurane; TIVA, total intravenous anesthesia.

All patients stayed in the post-anesthesia care unit (PACU) for 2 hours. During the PACU stay, pain was assessed using the Numerical Rating Scale (NRS) every 30 minutes. Ten patients had an NRS of 0 to 1 at all time points, and one (TIVA group) had a pain score of 6 at the 30-minute time point, which was treated with 3 mg of intravenous morphine and at 60 minutes, the NRS score had decreased to 1. The other two patients (one in each group) had NRS scores of 3 and 4 at 30 minutes, which decreased to 0 to 1 at 60 minutes without administering analgesics. The details of NRS score at PACU stay are depicted in [Table 3].

Table 3 Numerical Rating Scale at various time points at PACU and in the ward during the first 48 hours after surgery

Patient number	Maximum NRS -PACU	NRS 2 h	NRS 6 h	NRS 12 h	NRS 24 h	NRS 36 h	NRS 48 h
TIVA maintenance
1	6	0	1	3	0	0	0
2	0	0	3	0	0	0	0
3	0	0	2	2	0	2	0
4	3	0	0	0	0	0	0
5	0	0	0	0	0	0	0
6	1	2	2	0	0	0	2
7	0	1	2	1	2	0	0
8	0	2	3	2	6	2	2
Sevoflurane maintenance
9	0	0	2	0	0	0	0
10	0	3	0	0	0	0	0
11	4	3	4	2	3	2	6
12	0	0	0	0	0	0	0
13	0	2	2	2	2	4	3

Abbreviations: NRS, Numerical Rating Scale; PACU, post-anesthesia care unit.

Postoperatively, 12 patients received epidural morphine (140 μg/h), and one patient received ropivacaine (0.06%) and morphine (75 μg/h) for 48 hours. Postoperative hemodynamics were stable during the first 48 hours. The mean time for oral fluid administration was 3.88 ± 2.31 hours. Patients were sitting up and moving around the bed the next day and were ambulated with a lumbar corset belt on the second postoperative day. The mean ambulation time was 2.07 ± 0.35 days ([Table 2]). All patients' pain scores (NRS) were <4 at all time points, except one whose pain score was 6 at 24 hours, which subsided with paracetamol and ketorolac administration. Postoperative NRSs at various time points during the first 48 hours, including PACU, are shown in [Table 3]. Three patients (3/13) developed postoperative nausea and vomiting (PONV; 2 in sevoflurane and 1 in TIVA maintenance), which was treated with ondansetron 4 mg every 8th hour for 48 hours. None of the patients had respiratory depression, excessive sedation, paralytic ileus or pruritus needing treatment, or a high dependency unit admission. The average length of hospital stay was 4.85 ± 2.08 (range: 3–11) days.

One patient who received ropivacaine (0.06%) with morphine (75 μg/h) developed right ankle weakness on the first postoperative day. Although the weakness was attributed to surgical handling, the epidural catheter was removed the next day after surgery. Postoperative computed tomography-lumbar spine revealed proper screw and cage placement. Electromyography revealed reduced compound muscle action potentials in the right peroneal and bilateral tibial nerves. The weakness slowly improved to normal power over the next 24 hours, and he was discharged on the fourth postoperative day.

Discussion

The result of this case series showed bilateral, single-shot ESPB before the surgical incision for intraoperative analgesia, followed by a continuous low-dose epidural morphine infusion via an intraoperatively placed epidural catheter at the end of the surgery, provided excellent perioperative analgesia with minimal side effects. This technique avoids the need for large doses of systemic morphine for perioperative analgesia, thereby avoiding side effects while maintaining hemodynamic stability. However, studies have shown that the addition of local anesthetics to morphine improves analgesia through its additive effect. We did not add ropivacaine to morphine except in one patient for analgesia, as it may cause hypotension, which is detrimental after spine surgery and can interfere with neurological examination.

Since single-shot administration of bilateral ESPB before surgery provides intraoperative analgesia, and the postoperative analgesia lasts only 8 to 10 hours after surgery, a bilateral ESPB catheter is needed to provide continuous postoperative analgesia.[8] Bilateral catheter placement for postoperative analgesia following major lumbar spine surgery has been described in the literature.[6] However, it is not very popular as this technique is not cost-effective, and there is a concern about local anesthetic-induced systemic toxicity, especially in small-built patients. Administration of large doses of systemic morphine can cause side effects, such as sedation, respiratory depression, and PONV. Intermittent bolus administration of epidural morphine (3–4 mg/every 24 hours) provides adequate analgesia, but it can also be associated with side effects. There are reports of continuous infusion of epidural morphine (100 μg/h) following cardiac and thoracic surgery, and they show that this technique is associated with a lower serum concentration of morphine and cortisol levels and fewer side effects compared with bolus epidural.[10] [11] The literature search did not reveal any study or anecdotal case report of continuous epidural morphine infusion for postoperative analgesia following major lumbar spine surgery using an elastomeric pump. This technique is simple, safe, and cost-effective while providing adequate analgesia.

In this era of enhanced recovery after surgery, maximal utilization of regional analgesic techniques is necessary to improve analgesia. This technique provides excellent analgesia, promotes early ambulation, and enhances recovery. It has some limitations; it cannot be used if there is a preoperative anatomical abnormality involving the lumbar spine, intraoperative CSF leak, and in patients who had previous lumbar spine surgery at the same or higher level.

Conclusion

This combined regional technique provides excellent analgesia in both intraoperative and postoperative periods, promotes early ambulation, and enhances recovery following major lumbar spine surgery. Randomized controlled trials are required to confirm these findings.

Conflict of interest

None declared.

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Publication History

Article published online:
25 April 2025