Evaluation of ultrasound-guided erector spinae plane block for postoperative management of video-assisted thoracoscopic surgery: a prospective, randomized, controlled clinical trial

Abstract

Background: Video-assisted thoracoscopic surgery (VATS) is a commonly performed minimally invasive procedure that has led to lower levels of pain, as well as procedure-related mortality and morbidity. However, VATS requires analgesia that blocks both visceral and somatic nerve fibers for more effective pain control. This randomized controlled trial evaluated the effect of erector spinae plane block (ESPB) in the postoperative analgesia management of patients undergoing VATS.

Methods: We performed a prospective, randomized, single-center study between December 2018 and December 2019. Fifty-four patients were recruited to two equal groups (ESPB and control group). Following exclusion, 46 patients were included in the final analysis. Patients were randomly assigned to receive preoperative ultrasound-guided ESPB with either ropivacaine or saline. The primary outcome was the numeric rating scale (NRS) score, assessed 12 hours postoperatively. Secondary outcomes were the Riker Sedation-Agitation Scale (SAS) score for emergence agitation, postoperative cumulative opioid consumption, length of post-anesthesia care unit (PACU) stay, incidence of postoperative nausea and vomiting (PONV) and dizziness, and ESPB-related adverse events.

Results: The NRS in the ESPB group during the postoperative period immediately after PACU admission was significantly lower than that in the control group (5.96±1.68 and 7.59±1.18, respectively; P<0.001) and remained lower until 6 hours postoperatively (P=0.001 at 1 hour and P=0.005 at 6 hours). At 12 hours postoperatively, NRS scores were not significantly different between groups (P=0.12). The median [interquartile range (IQR)] of the postoperative rescue pethidine consumption in PACU was significantly lower [25 mg (25 mg)] in the ESPB group than that in the control group [50 mg (56.2 mg); P=0.006]. The median (IQR) of PACU residual time was significantly lower [25 min (10 min)] in the ESPB group than that in the control group [30 min (15 min); P=0.034]. The median (IQR) Riker SAS was also lower in the ESPB group [4 (1.0)] than that in the control group [5 (1.25); P<0.001] in PACU.

Conclusions: A single preoperative injection of ESPB with ropivacaine may improve acute postoperative analgesia and emergence agitation in patients undergoing VATS.

Keywords: Video-assisted thoracoscopic surgery (VATS); erector spinae plane block; paravertebral block; thoracic epidural blockade; ultrasound.

Figure 1

Schematic diagram of erector spinae plane block. A needle was inserted into the interfascial plane between the erector spinae muscle and transverse process of the vertebra.

Figure 2

Sonoanatomy and technique of the erector spinae plane block. (A) The ultrasound transducer is placed longitudinally, 2 to 3 cm lateral to the T5 transverse process, under aseptic conditions. The needle is inserted in a cranial-to-caudal direction in-plane; (B) correct needle tip placement is identified by hypoechoic local anesthetic under the erector spinae muscle, setting it apart from the transverse processes.

Figure 3

CONSORT flow diagram. ESPB, erector spinae plane block.

Figure 4

Comparison of postoperative NRS scores, for ESPB Group and Control Group at various time points of follow up. (A) Data in which the 7 patients with conversion of VATS to open thoracotomy were excluded; (B) all patient data including 7 patients with conversion of VATS to open thoracotomy. **P<0.001, *P<0.05. ESPB, erector spinae plane block; PACU, post-anesthesia care unit; NRS, numeric rating scale; VATS, video-assisted thoracoscopic surgery.