Intercostal nerve blocks take the lead: rethinking regional analgesia for video-assisted thoracic surgery

Video-assisted thoracoscopic surgery (VATS) is an established and reliable approach for segmentectomy and lobectomy within the domain of thoracic surgery. Nonetheless, while uniportal VATS techniques have demonstrated reductions in pain and opioid consumption relative to multiportal approaches and traditional open thoracotomy, patients undergoing the former may still encounter considerable postoperative discomfort (1).

In a recent manuscript published in Anesthesiology (2), Coppens et al. hypothesized that thoracoscopy-guided intercostal nerve blocks (ICNBs) would result in superior analgesic effects compared to erector spinae plane blocks (ESPBs). In their study, 100 adult patients undergoing uniportal VATS were equally allocated into two groups: one group of patients received an active thoracoscopy-guided ICNB (with 30 mL of 0.5% ropivacaine) and a placebo ESPB (with 30 mL of saline), while the other group received an active ESPB (with 30 mL of 0.5% ropivacaine) and a placebo ICNB (with 30 mL of saline). The authors demonstrated that the group receiving active ICNBs experienced a statistically significant and clinically relevant reduction in morphine consumption (10.9 vs. 17.6 mg, P=0.0015) 12 hours after surgery compared to those receiving active ESPBs. Secondary endpoints also showed that the active ICNB group fared better with reduced patient-reported pain scores from 30 minutes to 2 hours postoperatively and lower need for rescue pain medications in the post-anesthesia care unit (PACU) (16% vs. 44%, P=0.0033). Notably, the authors observed low median pain scores in both groups at 12 (ICNB: 1 vs. ESPB: 0, P=0.213) and 24 hours after surgery (ICNB: 1.5 vs. ESPB: 1, P=0.912). However, patients in the active ESPB group still showed a greater 24-hour morphine consumption (26.7 vs. 18.7 mg, P=0.018) and required more adjuvant analgesic management the day after surgery (76% vs. 52%, P=0.0178). Patient satisfaction and postoperative safety outcomes were similar between groups, as was hospital length of stay (ICNB: 2 days vs. ESPB: 3 days, P=0.546).

The ESPB exerts its analgesic effects through the cranio-caudal spread of local anesthetics beneath the erector spinae fascia and to the anterior and dorsal rami. In contrast, thoracoscopy-guided ICNB involves direct visualization and injection of the local anesthetics around the neurovascular bundle. We agree with the authors that variability in the spread and diffusion of the local anesthetic through fascial planes can limit ESPB efficacy, which explains the superior analgesia observed in the ICNB arm. Cadaveric anatomical studies have demonstrated the variable distribution of the ESPB within fascial planes, often not reaching the paravertebral space and anterior rami spinal nerves (3,4).

Coppens’ work has several strengths, including its methodological design, which included an active (ropivacaine) and placebo (saline) block for each arm, thereby specifically assessing the analgesic effects of the active treatments. Additionally, both the surgeon and anesthesiologist were blinded to the assigned intervention, decreasing the risk of bias. Another strength is that ICNBs were performed by multiple surgeons, thereby making the results generalizable and less reliant on a specific technique.

Coppens’ work also highlights aspects related to the pain management of patients undergoing uniportal VATS, regardless of nerve block technique. First, patient satisfaction was high in both cohorts. This suggests that even when the study showed immediate, statistically and clinically relevant differences in pain relief, satisfaction with care was not compromised—most likely because pain intensity remained mild in both groups, as reported. Second, the study’s findings suggest that rebound pain—although not studied—was not a clinical problem. While pain scores increased after 24 hours, they remained within the mild intensity range, likely related to the use of a multimodal analgesic approach. Third, although the ICNB achieved greater pain relief in the PACU—as median pain scores were virtually zero at all assessment points—it remains unclear whether the analgesic effects of the blocks were short-lived (5).

Clinical studies have shown wide variability in analgesic duration for ICNBs and ESPBs, ranging from 4 to 12 hours with the intercostal approach and up to 24 hours with ESPBs (6-8). In Coppens’ work, both groups required opioids over 24 hours to manage postoperative pain, but no information was provided about the timing or frequency of individual doses, which would shed light on when the block’s effect began to fade. Additionally, it is essential to note that pain after thoracic surgery is not solely derived from incisional trauma per se. Diaphragm, pleural, and muscle irritation can result in the development of ipsilateral shoulder pain, affecting approximately one-third of patients undergoing VATS, and two-thirds of open thoracotomy patients (9). Ipsilateral shoulder pain is challenging to treat and persists in approximately 8% of patients 12 months after thoracic surgery (9). Recent studies suggest that regional anesthetic techniques such as phrenic and interscalene nerve blocks could improve ipsilateral shoulder pain (10,11); however, ICNBs and ESPBs have shown limited benefit (12).

We are optimistic that Coppens et al.’s work will change clinical practice, but its impact remains unknown. The American Society of Anesthesiologists (ASA) and the procedure-specific postoperative pain management (PROSPECT) guidelines do not recommend incorporating ICNB into perioperative analgesic management in VATS (13,14). It is worth noticing that the ASA strongly recommends the use of fascial plane blocks, including the ESPB, for minimally invasive thoracic procedures. This is based on a 1-point reduction in pain scores, which is considered a minimal clinically important difference. However, Coppens’ results demonstrating favorable findings with ICNBs were not included in the ASA guidelines, likely due to their publication at nearly the same time as the ASA recommendations.

Coppens’ work and the findings of three other randomized controlled trials invite us to revisit the role of ICNBs as an effective technique following thoracoscopic surgery (6,7,15). Dai et al. (6) conducted a study including 60 patients undergoing uniportal VATS and reported that thoracoscopy-guided ICNBs provided superior early analgesic effects at four and eight hours postoperatively compared with ESPBs, but the clinical benefit disappeared at 24 hours. Turhan et al. (7) investigated the analgesic efficacy of thoracic paravertebral blocks (n=37), ultrasound-guided ESPBs (n=37), and surgeon-guided ICNBs (n=37) in patients undergoing VATS. Patients in the ICNB group exhibited slightly lower, but not clinically relevant, morphine requirements 24 hours postoperatively compared with the ESPB group (27.42 vs. 29.39 mg, P<0.017). Additionally, participants in the ICNB group had lower static (ICNB: 2 vs. ESPB: 3, P<0.017) and dynamic pain scores (ICNB: 3 vs. ESPB: 4, P<0.017) at 12 hours, and lower static pain scores 24 hours postoperatively (ICNB: 1 vs. ESPB: 2, P=0.017). Sung et al. (15) conducted a study (n=100) investigating the analgesic effects of ESPBs and surgeon-performed ICNBs in patients who underwent VATS. The interventions were performed at the beginning of surgery with 20 mL of 0.5% levobupivacaine, and postoperative pain was managed with a multimodal analgesic approach. The authors found no differences in postoperative pain scores. However, the median 24-hour morphine consumption was lower in the ICNB arm (0 mg) than in the ESPB arm (3 mg), but the difference was not statistically significant (P=0.051) nor clinically relevant.

One crucial question cannot be ignored, considering Coppens’ results: Is a surgeon-guided ICNB preferable to an ultrasound-guided ICNB? In a randomized controlled trial, Li et al. (16) compared the analgesic effects of surgeon-performed ICNB and ultrasound-guided ICNB in 60 patients undergoing uniportal VATS. The authors reported that surgeon-performed ICNB resulted in earlier opioid requirements compared to the ultrasound-guided approach (18.3 vs. 22.6 hours, P<0.001). However, there were no differences in cumulative opioid consumption 24 hours postoperatively, and pain intensity was comparable between groups up to 48 hours postoperatively. No differences in adverse effects or block-related complications were reported between groups. Notably, surgeon-guided ICNB required less surgical time and achieved a higher success rate on the first attempt at needle placement in the target intercostal space. Consequently, in patients undergoing uniportal VATS, we could consider surgeon-performed ICNBs a more efficient approach, with analgesic effects and safety outcomes similar to those of ultrasound-guided ICNBs.

As noted by Coppens et al., plasma ropivacaine concentrations were significantly higher in the active ESPB group up to 1 hour after the block; however, no instances of local anesthetic systemic toxicity were reported in either group. Studies in humans suggest that systemic local anesthetic absorption may also explain the analgesic effects of ESPBs (17). Nonetheless, further research is needed to determine whether differences in plasma ropivacaine levels after ESPBs vs. ICNBs translate into systemic analgesic effects.

The work by Coppens et al. has some limitations. First, both centers in this study were based in Belgium and shared the same enhanced recovery after thoracic surgery protocol. Therefore, it is unknown whether these blocks would have the same efficacy in centers with variations in their enhanced recovery programs. Second, the study was designed to assess 12-hour morphine consumption as the primary outcome and 24-hour morphine consumption as the secondary outcome. The study was underpowered to assess safety outcomes such as local anesthetic systemic toxicity and length of hospital stay. Lastly, the long-term impact of surgeon-guided ICNB in chronic postsurgical pain remains to be elucidated, as patients were not followed beyond hospital discharge.

In conclusion, surgically guided ICNBs appear to be superior to ultrasound-guided ESPBs in many respects, but both provide adequate analgesia after minimally invasive thoracic surgery when combined with multimodal analgesia. Hence, in centers where surgically guided ICNBs cannot be performed, ultrasound-guided fascial plane blocks, such as ESPBs or paravertebral blocks, are a good analgesic strategy. Less is known about the efficacy of other blocks, such as the different versions of serratus blocks. Future anesthesia guidelines should consider the inclusion of surgically guided ICNBs in patients undergoing thoracic surgery, particularly uniportal VATS, for management of postoperative analgesia.

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