Background

The efficacy of serratus anterior plane block for treatment of pain after minimally invasive thoracic surgery remains unclear. This trial assesses the impact of serratus anterior plane block on postoperative opioid consumption and on measures of early recovery after thoracoscopic lung resection.

Methods

Patients undergoing minimally invasive anatomic lung resection at a single center were randomized to undergo serratus anterior plane block with 40 ml injectate containing bupivacaine 0.25%, clonidine 100 μg, and dexamethasone 4 mg (serratus anterior plane block group) or sham block with 40 ml normal saline (placebo group) at the conclusion of surgery. The primary outcome was cumulative intravenous morphine equivalents during the first 24 h postoperatively. Secondary outcomes were intravenous morphine equivalents, pain scores at rest and with cough, inspiratory volume on incentive spirometry, incidence of nausea or vomiting during the first 48 h postoperatively, Quality of Recovery–15 score on postoperative day 7, and length of stay.

Results

Using the protocol-specified intention-to-treat analysis, the median (interquartile range) intravenous morphine equivalents was 10.6 (5.0 to 27.1) mg in serratus anterior plane block patients (n = 46) versus 18.8 (9.9 to 29.6) mg in placebo patients (n = 46; 32% reduction; ratio, 0.68 [95% CI, 0.44 to 1.06]; P = 0.085). Of the secondary outcomes, only the composite pain with cough scores differed significantly in the serratus anterior plane block group by a coefficient of –0.41 (95% CI, –0.81 to –0.01; P = 0.044). A sensitivity as-treated analysis reported median (interquartile range) intravenous morphine equivalents of 10.0 (5.0 to 27.2) mg in serratus anterior plane block patients (n = 44) versus 19.9 (10.4 to 29.0) mg in placebo patients (n = 48; 36% reduction; ratio, 0.64 [95% CI, 0.41 to 1.00]; P = 0.048).

Conclusions

The protocol-specified intention-to-treat analysis demonstrated that serratus anterior plane block did not result in a significant reduction in opioid consumption when added to a multimodal analgesic regimen after thoracoscopic anatomic lung resection. The sensitivity as-treated analysis showed a significant and modest clinical reduction in the primary outcome that warrants further investigation.

Editor’s Perspective
What We Already Know about This Topic
  • Minimally invasive thoracic lung surgery (e.g., video-assisted or robotic-assisted thoracoscopic surgeries) is associated with fewer postoperative pulmonary complications and faster postoperative recovery when compared with patients who undergo thoracic lung surgery via open thoracotomy.
  • Patients who undergo minimally invasive thoracic surgery have multiple post-site incisions that may cause significant chest wall pain without intraoperative and postoperative pain management.
  • Enhanced recovery protocols for thoracic surgeries exist at many hospitals and typically include a multimodal approach to pain management. Some centers include placing a serratus anterior fascial plane block after surgery.
  • It remains unclear whether placing a serratus anterior plane block at the end of lung surgery adds significantly to pain control achieved with intraoperative intravenous medications and intercostal blocks placed at the end of surgery.
What This Article Tells Us That Is New
  • This study is a single-center prospective randomized clinical trial of 99 patients who underwent minimally invasive thoracic lung surgery.
  • All patients received intraoperative intravenous fentanyl, dexamethasone, dexmedetomidine, acetaminophen, and ketorolac and postoperative intercostal blocks. Patients were randomized to additionally receive a serratus anterior plane block at the end of surgery or to receive a placebo serratus anterior plane block.
  • The primary study outcome was cumulative intravenous morphine equivalents received in the first 24 h after surgery.
  • Intention-to-treat analysis found that 24-h postoperative intravenous morphine equivalents were not significantly increased for the placebo group compared with the intervention group. An additional as-treated analysis found that the intravenous morphine equivalents received by the placebo group were significantly but modestly higher at 24 h after surgery than the intravenous morphine equivalents received by the serratus anterior plane block group.
  • Future studies may be warranted to further explore potential benefit of serratus anterior plane blocks in minimally invasive thoracic lung surgery patients.