Intermittent Erector Spinae Plane Block for Postoperative Pain Control after Open Nephrectomy

Introduction

Postoperative pain management is a crucial aspect of patient care after major surgeries like open nephrectomy. Traditional methods often rely on systemic analgesics, which can have side effects. Recently, regional anesthesia techniques have gained attention for their potential to provide effective and targeted pain relief. One such technique is the erector spinae plane block (ESPB). This article presents a case report where intermittent ESPB was used as part of multimodal analgesia after open nephrectomy, highlighting its effectiveness and potential mechanisms.

Case Presentation

A 69-year-old female patient (height: 155 cm, weight: 54 kg) underwent a left open nephrectomy for renal cell carcinoma. The surgery was performed under general anesthesia with a 15-cm flank incision. After the surgery, ESPB was administered at the T7 level. The procedure involved injecting 20 mL of 0.375% ropivacaine with epinephrine (1:200,000) to prevent systemic toxicity, followed by catheter insertion. Postoperative pain control was multimodal, including 80 mg oral zaltoprofen twice daily, intermittent ESPB catheter injections (0.375% ropivacaine 20 mL with epinephrine 1:200,000 every 8 hours for 2 days), and intravenous patient-controlled analgesia (fentanyl 8 mg/mL, basal rate 1 mL/h, bolus 2 mL).

In the recovery room, the patient’s resting/dynamic (coughing, deep breathing) visual analogue scale (VAS) score was 2/3. On the pinprick test, there was complete sensory loss in the T2–T8 dermatome area and decreased sensation in T9–T10 dermatome compared to the contralateral side. Throughout the postoperative period, resting and dynamic (ambulation) VAS scores were maintained at 1 to 2 without additional analgesics. The patient was satisfied with the pain control and was discharged without complications.

Mechanisms of ESPB Analgesia

Dorsal and Ventral Ramus Blockade

The sensory blockade observed in the patient (T2–T10 dermatome) suggests that ESPB can block multiple dorsal and ventral rami. This blockade can effectively address the somatic pain component of the incision site. Even if sympathetic fibers are not blocked, the blockade of dorsal and ventral rami can provide sufficient analgesia. This is because the somatic pain from the incision is mainly carried by these rami. For example, in other regional anesthesia techniques targeting similar nerve structures, effective pain relief has been achieved for surgical incisions (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4540737/).

Differential Fiber Blockade

ESPB may lead to differential blockade mediated by unmyelinated C fibers rather than larger A-delta and A-gamma fibers. While the conventional pinprick test in this patient showed T2–T10 dermatome blockade, it’s possible that a wider range was affected. According to Adhikary et al. (https://journals.lww.com/rapm/Abstract/2018/08000/Erector_Spinae_Plane_Block_versus_Retrolaminar.25.aspx), differential loss to pinprick may not be elicited despite analgesia. This is because unmyelinated C fibers (which transmit nociception) are blocked, while larger A delta fibers (mediating cold and sharp pain) may not be fully blocked. This differential blockade can still result in effective pain relief as the nociceptive input is reduced.

Significance and Future Directions

This case demonstrates that ESPB as part of multimodal analgesia can effectively control postoperative pain after open nephrectomy. However, it’s important to note that the exact mechanisms are still not fully understood. Further studies are needed to clarify the precise neural pathways involved, optimize the technique (such as the optimal injection site and volume), and compare it with other regional anesthesia techniques in larger patient populations. Additionally, long-term follow-up studies could assess the impact on patient recovery and quality of life.

Conclusion

The use of intermittent ESPB in this case provided excellent postoperative pain control. The potential mechanisms include dorsal and ventral ramus blockade and differential fiber blockade. While more research is required, this case highlights the promise of ESPB as a valuable addition to multimodal analgesia for open nephrectomy. It offers a targeted approach to pain management, reducing the reliance on systemic analgesics and potentially improving patient outcomes.

doi.org/10.1097/CM9.0000000000000269

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