Enhanced recovery with bilateral external oblique intercostal block in elderly patients undergoing extensive abdominal surgery: a case report

Abstract

Introduction

Major open abdominal surgery is often associated with significant post-operative pain. The external oblique intercostal (EOI) block is a thoracic plane block [1] that provides analgesia to the upper abdominal wall incisions without the sympathetic blockade associated with a thoracic epidural. The current PROSPECT guidelines recommend either a thoracic epidural or bilateral transverse abdominal plane (TAP) blocks for open liver resection. However, epidural analgesia has associated complications and side effects which can limit recovery, whilst TAP blocks or other abdominal fascial plane blocks, provide limited coverage of upper abdominal incisions. In the context of enhanced recovery after surgery, the EOI block provides good analgesia to upper abdominal incisions without the sympathetic blockade or motor effects seen with an epidural. We describe two cases in which bilateral continuous EOI block catheters provided effective analgesia for extensive upper abdominal incisions.

Case 1

An 87-year-old man [63.6 kg, body mass index (BMI) 23.7 kg/m²] with a pancreatic body tumour and moderate pericardial effusion presented for laparotomy, distal pancreatectomy, splenectomy. Bilateral EOI catheters were placed under anaesthesia. A Sonosite PX linear 13–6 MHz ultrasound probe was placed on the chest wall in the parasagittal orientation, between the midclavicular line and the anterior axillary line at the level of the 6th rib. Anatomical structures identified from superficial to deep include subcutaneous tissue, external oblique muscle, intercostal muscles, ribs, pleura, and lungs. The plane between the external oblique and intercostal muscles was identified (Fig. 1a) and hydrodissected with normal saline (Fig. 1b). Bilateral catheters were inserted and secured at 10 cm mark at the skin, with 7 cm in the EOI plane on the left and 6 cm on the right. An initial bolus of 0.2% Ropivacaine 25 mL per side was administered. Anaesthesia was maintained with sevoflurane (mean alveolar concentration 0.8-0.9), target-controlled infusion remifentanil up to 2 ng/mL, and dexmedetomidine 0.5 mcg/kg/h. Additional intraoperative analgesia comprised ketamine 10 mg and morphine 2 mg at wound closure. Surgical duration was 1 h 44 min, and no further EOI boluses were given intraoperatively.

Figure 1

An ultrasound image of an EOI plane block. A linear ultrasound probe was placed in the sagittal oblique plane, with the probe’s cranial end rotated slightly medially, at the level of the sixth rib, between the mid-clavicular and anterior axillary lines. The surrounding structures, including the sixth and seventh ribs, external oblique muscle, intercostal muscles and pleura, are labelled. (a) The highlighted line indicates the appropriate fascial plane (b) Ultrasound image showing local anaesthetic spread following the EOI injection. The blue line indicates the space between the external oblique and the intercostal muscle.

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In the post-anaesthesia care unit, the patient reported severe pain ~3 h after the initial EOI bolus. Breakthrough analgesia with 1% lignocaine 5 mL per catheter rapidly relieved pain, followed by 0.2% Ropivacaine 10 mL per side. Subsequently the patient was placed on a programmed intermittent bolus regimen of 0.2% Ropivacaine 20 mL every 3.5 h, without patient-controlled boluses. On the first postoperative day (POD), he was able to mobilize independently with only IV paracetamol as supplemental analgesia. At 24 h postoperatively, pain scores were 1 at rest and 5 with movement. At 48 h, pain scores were 1 at rest and 4 on movement. Daily sensory testing revealed reduced pinprick sensation from T6–T9 bilaterally. He did not require any rescue opioids the first 48 h, after which he was started on regular Tramadol 50 mg three times a day for 3 days (opioid morphine equivalents (OME): 30 mg per day) until he was discharged home. He was continued on programmed intermittent boluses of 20mls Ropivacaine 0.2% until the EOI catheters were removed on POD 4, and he was discharged home on POD 5.

Case 2

A 65-year-old man (92 kg, BMI 31.6 kg/m²) with chronic hepatitis B underwent left hepatectomy, middle hepatic vein tumour thrombus evacuation, lymphadenectomy, and intraoperative microwave ablation via an upper midline incision with right subcostal extension (Fig. 2). After induction, bilateral EOI catheters were inserted using the same ultrasound-guided approach. Initial boluses of 0.2% Ropivacaine 30 mL per side were administered.

Figure 2

Right upper midline incision with subcostal extension.

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During right subcostal extension, haemodynamic lability required remifentanil escalation to 2.5 ng/mL, esmolol 60 mg, and nitroglycerin 585 mcg. Further EOI boluses were deferred until specimen retrieval at 6.5 h, given anticipated hemodynamic swings. At which point, 20 mL of 0.2% ropivacaine via the right catheter reduced remifentanil requirement from 1.5 to 0.1 ng/mL within 20 min. Surgical time was 10 h with blood loss of 1200 mL. He was started on an intermittent bolus regimen of 20mls 0.2% Ropivacaine every 4 h, with a staggered duration of 2 h between each catheter.

In the Post Anaesthetic Care Unit, the patient was comfortable and denied pain. On POD 1, his pain score at rest was 0, but reported 5/10 pain on movement. However, he declined all rescue tramadol doses. Sensory testing showed reduced pinprick sensation over T2–T8 bilaterally. At 48 h his pain score at rest was 1, his pain score on movement was 4. He ambulated 80 m. EOI catheters were removed on POD 5 and he was discharged on POD 9. He only required 1 dose of rescue tramadol 50 mg on POD5, after the catheters were first removed. Opioid consumption at 24 h and 48 h were 0 mg OME. Patient was discharged home on POD 9.

Discussion

These cases illustrate that bilateral continuous EOI catheters can provide effective somatic analgesia for extensive upper abdominal incisions with minimal systemic opioids and early mobilization in high-risk patients. Postoperative pain after major abdominal surgery is associated with higher rates of respiratory complications [2], and upper abdominal incisions compromise diaphragmatic excursion [3]. Whilst thoracic epidural analgesia remains the gold standard for pain relief and reduction of respiratory morbidity [4, 5], its complications limit use in patients with anticipated coagulopathy or haemodynamic instability [6, 7].

Alternative fascial plane blocks such as TAP and erector spinae plane blocks carry lower neuraxial risk but inadequately cover the upper abdominal dermatomes [8], missing the lateral cutaneous branches supplying the upper anterior abdominal wall [9]. Rhomboid intercostal serratus blocks predominantly cover lateral cutaneous branches from T3–T9 but spares anterior branches [10]. Cadaveric studies of the EOI block demonstrate spread deep to the external oblique and serratus anterior muscles, enveloping anterior and lateral cutaneous branches from T6/7–T10 [11], matching the requirements of subcostal and rooftop incisions.

The EOI block is performed supine, is technically straightforward, and is distant from the hepatobiliary operative field [11, 12]. Its superficial, compressible location makes it attractive when postoperative anticoagulation or coagulopathy is anticipated [12]. In our cases, these advantages permitted safe catheter placement without neuraxial instrumentation.

Both patients had low opioid requirements and favourable functional recovery, in keeping with previous case reports [13, 14]. In Case 1, early breakthrough pain ~3 h after the initial bolus suggests limited single-shot duration, likely reflecting high vascular absorption in this plane, supporting preferential use of continuous catheter techniques. In Case 2, reduced remifentanil requirements after a right-sided EOI bolus illustrates intraoperative utility for attenuating nociception from subcostal retraction. Neither patient had any catheter related complications, nor had complications from local anaesthetic systemic toxicity (LAST).

Principal risks include pneumothorax given pleural proximity, and LAST given the volumes used; no toxicity has been reported at 30–40 mL per side, but careful dosing remains essential [9, 13, 14]. The EOI block does not provide visceral analgesia and should be integrated into a multimodal regimen. Opioid-sparing effects are also seen in laparoscopic surgery, with one randomized trial reporting 46.4% lower postoperative opioid consumption with EOI blockade [14].

Evidence for the EOI block remains limited to case reports, small series, and one trial. Larger comparative studies with thoracic epidural, TAP, and other fascial plane blocks, and further work defining optimal local anaesthetic dosing and infusion strategies for open surgery, are needed.

The EOI block provided excellent analgesia for extensive upper abdominal incisions in a high-risk elderly patients, enabling early mobilization and enhanced recovery. It presents a viable alternative to epidural analgesia, particularly when neuraxial techniques are contraindicated, though further studies are needed to confirm efficacy and optimal dosing.

Author contributions

B.J. provided major contribution the manuscript. S.C. performed the anaesthetic management of the case and contributed to manuscript editing. C.C.H. supervised the project and critically revised the manuscript. All authors read and approved the final manuscript.

Conflicts of interest

The authors declare there are no conflicts of interest and have nothing to disclose.

Funding

The authors declare there was no funding received.

Data availability

Not applicable.

Consent for publication

Authors declare that informed consent was obtained from the patient.

References