Quest for the Elusive Mechanism of Action for the Thoracic Paraspinal Nerve Block Techniques. Are We Ignoring the Anatomy of the "Retro Superior Costotransverse Ligament Space?"

Comparison of Ultrasound-Guided Thoracic Paravertebral Block Versus Thoracic Paravertebral Block Combined With Serratus Anterior Plane Block or Erector Spinae Block Following Video-Assisted Thoracoscopic Lobectomy

Purpose

Compared the efficacy of ultrasound-guided thoracic paravertebral block (TPVB) and thoracic paravertebral combined with serratus anterior plane block (SAPB) or erector spinae block (ESPB) following video-assisted thoracoscopic lobectomy(VATL).

Patients and Methods

This retrospective study analyzed the medical records of 295 patients who underwent VATL surgery between August 2021 and January 2023. Patients were divided into three groups: TPVB (92 patients), TPVB combined with SAPB (106 patients), and TPVB combined with ESPB (97 patients). The primary outcomes were postoperative pain levels, measured using an 11-point visual analogue scale (VAS) both at rest and during coughing at 2, 6, 12, 24, and 48 hours postoperatively, as well as cumulative oxycodone consumption within 24 and 48 hours postoperatively.

Results

Postoperative cumulative oxycodone consumption within 24 and 48 hours was significantly lower in the TPVB+SAPB and TPVB+ESPB groups compared to the TPVB group (P < 0.001), with no significant difference between the TPVB+SAPB and TPVB+ESPB groups. The TPVB group exhibited higher VAS pain scores both at rest and during coughing at 2 and 6 hours postoperatively compared to the other two groups (P < 0.005). Within 24 hours postoperatively, the Area Under Curve (AUC) for VAS scores at rest was significantly lower in the TPVB+SAPB group than in the other two groups (P < 0.05), while the AUC for coughing pain was significantly lower in the TPVB+ESPB group compared to the TPVB group (P = 0.049). Nausea or vomiting occurred more frequently in the TPVB group compared to the other groups (P = 0.016).

Conclusion

TPVB combined with SAPB or ESPB provides superior analgesic effects compared to TPVB alone after video-assisted thoracoscopic lobectomy, with both techniques showing comparable analgesic efficacy. However, TPVB+SAPB may offer slightly better analgesia at rest, while TPVB+ESPB may have a potential advantage in reducing postoperative nausea and vomiting.

Comparison between ultrasound-guided intertransverse process and erector spinae plane blocks for breast cancer surgery: A randomised controlled trial

BACKGROUND

Clinical comparisons between intertransverse process block (ITPB) and erector spinae plane block (ESPB) are lacking.

OBJECTIVE

This study aimed to compare their blocking profile and clinical efficacy in breast cancer surgery.

DESIGN

Randomised, blinded, active-controlled superiority trial.

SETTING

A tertiary hospital in China from 20 February to 31 July 2023.

PATIENTS

Sixty-eight females undergoing unilateral breast cancer surgery.

INTERVENTION

Patients were randomised to receive either ITPB performed at T2-6 (5 ml of 0.5% ropivacaine per level) or ESPB at T4 (25 ml of 0.5% ropivacaine). General anaesthesia and postoperative analgesia were standardised.

MAIN OUTCOME MEASURES

The primary outcome was the number of blocked dermatomes at anterior T2-7, assessed 45 min after block completion, with a predefined superiority margin of 1.5 dermatomes. The important secondary outcome was the worst resting pain scores (11-point numerical rating scale) within 30 min in the recovery room, which was tested following a gatekeeping procedure. Other secondary outcomes included resting pain scores at various time points, use of rescue analgesics, opioid consumption, patient satisfaction, recovery quality score, and adverse effects within 24 h postoperatively.

RESULTS

The ITPB group showed a median [q1, q3] of 5 [4, 6] blocked dermatomes at anterior T2-7, whereas the ESPB group had 1 [0, 4], with a median difference of 4 (95% confidence interval (CI), 3 to 4); the lower 95% CI limit exceeded the predefined superiority margin of 1.5 (superiority P  < 0.001). Worst resting pain scores within 30 min in the recovery room in the ITPB group were 1 [0, 2] vs. 3 [1, 4] in the ESPB group, with a median difference of -1 (95% CI, -2 to 0; P  = 0.004). Patients in the ITPB group required fewer rescue analgesics within 30 min in the recovery room than did those in the ESPB group. No other clinically relevant results were observed in the secondary outcomes.

CONCLUSIONS

Although ITPB demonstrated more consistent anterior dermatomal spread and improved immediate postoperative analgesia compared to ESPB, no additional benefits were identified for breast cancer surgery. Future studies may investigate the potential of ITPB for surgical anaesthesia.

TRIAL REGISTRATION

www.chictr.org.cn (ChiCTR2300068454).

Intertransverse process block (ITPB) at the retro-superior costotransverse ligament (retro-SCTL) space: Evaluation of local anesthetic spread using MRI and sensory blockade in healthy volunteers

BACKGROUND

This study evaluated the spread of a local anesthetic, using MRI and sensory blockade, after an intertransverse process block (ITPB) at the medial aspect of the retro-superior costotransverse ligament (retro-SCTL) space - the medial retro-SCTL space block.

METHODS

Ten healthy volunteers received a single-injection ultrasound-guided medial retro-SCTL space block at the T4-T5 level using a mixture of 10 ml 0.5 % bupivacaine with 0.5 ml gadolinium. At 15 min, they underwent a high resolution, fat suppressed, T1 weighted MRI scan of the cervicothoracic spine. Loss of sensation to cold was assessed at 15 and 60 min, and then hourly for 5-h, after the block.

RESULTS

MRI showed consistent (100 %) spread of local anesthetic to the intercostal and paravertebral spaces, anterolateral aspect of the vertebral body (sympathetic chain), costotransverse space, neural foramina, and epidural space in all participants. However, sensory blockade was variable across the ipsilateral hemithorax. Hypoesthesia was more common than anesthesia in both the anterior (median [IQR], 3.5 [2-5] vs 0 [0-1.25], p < 0.001) and posterior (median [IQR], 6[3-7] vs 2[1-3], p < 0.001) hemithorax. Additionally, more dermatomes exhibited anesthesia in the posterior compared to the anterior hemithorax (median [IQR], 2[1-3] vs 0[0-1.25], p = 0.01). A variable number of contralateral dermatomes were also affected in 3 (30 %) volunteers. There was no statistically significant correlation between the local anesthetic spread and the number of hypoesthetic (r = 0.53, p = 0.11) or anesthetic (r = 0.09, p = 0.78) dermatomes on the ipsilateral hemithorax.

CONCLUSIONS

A single-injection medial retro-SCTL space block, at the T4-T5 level with 10.5 ml of local anesthetic, consistently spreads to the ipsilateral intercostal and paravertebral spaces, sympathetic chain, costotransverse space, neural foramina and epidural space, but produces ipsilateral sensory blockade that is variable and wider over the posterior than anterior hemithorax.

Retro superior costotransverse ligament space block as an effective analgesia after laparoscopic gastrectomy -a case report

BACKGROUND

The retro superior costotransverse ligament space (RSS) block, reported as a novel target in paraspinal block, involves the spreading of local anesthetics into the thoracic paravertebral space through slits around the superior costotransverse ligament . This blocks not only the dorsal rami but also the ventral rami, achieving a reliable complete sensory blockade.

CASE

We performed an RSS block at the T5, T7, and T9 levels on both sides for postoperative analgesia in two patients who underwent laparoscopic gastrectomy. Both patients showed complete sensory blockade from T4 to L1 on the anterior, lateral, and posterior chest walls in the recovery room. The resting and dynamic pain scores were 0 at 30 min and 6 h postoperatively. The pain score consistently remained below 3 throughout postoperative period.

CONCLUSIONS

The RSS block provided effective postoperative analgesia in laparoscopic gastrectomy through definitive complete sensory blockade.

Differential nerve blockade to explain anterior thoracic analgesia without sensory blockade after an erector spinae plane block may be wishful thinking

Ultrasound-guided erector spinae plane block (ESPB) is currently used as a component of multimodal analgesic regimen in a multitude of indications but the mechanism by which it produces anterior thoracic analgesia remains a subject of controversy. This is primarily the result of ESPB's failure to consistently produce cutaneous sensory blockade (to pinprick and cold sensation) over the anterior hemithorax. Nevertheless, ESPB appears to provide 'clinically meaningful analgesia' in various clinical settings. Lately, it has been proposed that the discrepancy between clinical analgesia and cutaneous sensory blockade could be the result of differential nerve blockade at the level of the dorsal root ganglion. In particular, it is claimed that at a low concentration of local anesthetic, the C nerve fibers would be preferentially blocked than the Aδ nerve fibers. However, the proposal that isolated C fiber mediated analgesia with preserved Aδ fiber mediated cold and pinprick sensation after an ESPB is unlikely, has never been demonstrated and, thus, without sufficient evidence, cannot be attributed to the presumed analgesic effects of an ESPB.