Comparison of analgesic efficacy between two approaches of paravertebral block for thoracotomy: A randomised trial

Although several approaches for ultrasound-guided thoracic paravertebral block have been introduced, little is known regarding the differences in analgesic efficacy. We conducted this prospective randomised trial to examine whether the type of approach for ultrasound-guided thoracic paravertebral block could affect analgesic quality in thoracotomy.

Patients scheduled for video-assisted thoracotomy were randomly allocated into two groups by block technique: the intercostal approach (group IC) or the paralaminar approach (group PL). At the start and end of surgery, 20 mL of 0.5% ropivacaine was injected, followed by a continuous infusion of 0.2% ropivacaine at 5 mL h^-1 . We also started intravenous fentanyl patient-controlled analgesia at 0.5 μg kg^-1  h^-1 and bolus dose of 15 μg. The main outcome was the number of rescue fentanyl use. We also evaluated postoperative pain scores and number of blocked dermatomes showing a reduced sensation.

Enrolment was ceased because of implementation of a minimally invasive surgical method. Overall, 42 subjects completed the trial for analysis. The number of rescue fentanyl use in group PL was significantly less than that in group IC at 3, 6, 12 and 24 hour postoperatively. The numerical rating scale (NRS) at rest in group PL was significantly lower at 1, 3, 6, and 12 hour postoperatively. Patients in Group PL developed significantly wider sensory block level (median (IQR [range]); 4 (4-5 [2-7])) than those in Group IC (3 (3-3 [2-9])).

We suggested that paralaminar approach provided superior analgesia for thoracotomy rather than the intercostal approach.