Intercostal administration of liposomal bupivacaine as a prognostic nerve block prior to phenol neurolysis for intractable chest wall pain

Intercostal liposomal bupivacaine injection for rib fractures: A prospective randomized controlled trial

BACKGROUND

Blunt chest wall injury accounts for 15% of trauma admissions. Previous studies have shown that the number of rib fractures predicts inpatient opioid requirements, raising concerns for pharmacologic consequences, including hypotension, delirium, and opioid dependence. We hypothesized that intercostal injection of liposomal bupivacaine would reduce analgesia needs and improve spirometry metrics in trauma patients with rib fractures.

METHODS

A prospective, double-blinded, randomized placebo-control study was conducted at a Level I trauma center as a Food and Drug Administration investigational new drug study. Enrollment criteria included patients 18 years or older admitted to the intensive care unit with blunt chest wall trauma who could not achieve greater than 50% goal inspiratory capacity. Patients were randomized to liposomal bupivacaine or saline injections in up to six intercostal spaces. Primary outcome was to examine pain scores and breakthrough pain medications for 96-hour duration. The secondary endpoint was to evaluate the effects of analgesia on pulmonary physiology.

RESULTS

One hundred patients were enrolled, 50 per cohort, with similar demographics (Injury Severity Score, 17.9 bupivacaine 17.6 control) and comorbidities. Enrolled patients had a mean age of 60.5 years, and 47% were female. Rib fracture number, distribution, and targets for injection were similar between groups. While both groups displayed a decrease in opioid use over time, there was no change in mean daily pain scores. The bupivacaine group achieved higher incentive spirometry volumes over Days 1 and 2 (1095 mL, 1063 mL bupivacaine vs. 900 mL, 866 mL control). Hospital and intensive care unit lengths of stay were similar and there were no differences in postinjection pneumonia, use of epidural catheters or adverse events bet ween groups.

CONCLUSION

While intercostal liposomal bupivacaine injection is a safe method for rib fracture-related analgesia, it was not effective in reducing pain scores, opioid requirements, or hospital length of stay. Bupivacaine injection transiently improved incentive spirometry volumes, but without a reduction in the development of pneumonia.

LEVEL OF EVIDENCE

Therapeutic/care management, Level II.

A randomized clinical trial of single dose liposomal bupivacaine versus indwelling analgesic catheter in patients undergoing surgical stabilization of rib fractures

INTRODUCTION

Locoregional analgesia (LRA) remains underused in patients with chest wall injuries. Surgical stabilization of rib fractures (SSRF) offers an opportunity to deliver surgeon-directed LRA under direct visualization at the site of surgical intervention. We hypothesized that a single-dose liposomal bupivacaine (LB) intercostal nerve block provides comparable analgesia to an indwelling, peripheral nerve plane analgesic catheter with continuous bupivacaine infusion (IC), each placed during SSRF.

METHODS

Noninferiority, single-center, randomized clinical trial (2017-2020) was performed. Patients were randomized to receive either IC or LB during SSRF. The IC was tunneled into the surgical field (subscapular space), and LB involved thoracoscopic intercostal blocks of ribs 3 to 8. The primary outcome was the Sequential Clinical Assessment of Respiratory Function score, measured daily for 5 days postoperatively. Secondary outcomes included daily narcotic equivalents and failure of primary LRA, defined as requiring a second LRA modality.

RESULTS

Thirty-four patients were enrolled: 16 IC and 18 LB. Age, Injury Severity Score, RibScore, Blunt Pulmonary Contusion Score, and use of nonnarcotic analgesics was similar between groups. Duration of IC was 4.5 days. There were three failures in the IC group versus one in the LB group (p = 0.23). There was no significant difference in Sequential Clinical Assessment of Respiratory Function score between the IC and LB groups. On postoperative days 2 to 4, narcotic requirements were less than half in the LB, as compared with the IC group; however, this difference was not statistically significant. Average wholesale price was US $605 for IC and US $434 for LB.

CONCLUSION

In this noninferiority trial, LB provided at least comparable and potentially superior LRA as compared with IC among patients undergoing SSRF.

LEVEL OF EVIDENCE

Therapeutic, level II.

Intercostal Nerve Block Using an Innovative Intraneedle Ultrasound Transducer: A Proof-of-Concept study

Intercostal nerve block is a widely used and effective approach to providing regional anesthesia in the thoracic region for pain relief. However, during ultrasound-guided intercostal nerve block, inaccurate identification of the anatomic structures or suboptimal positioning of the needle tip may result in complications and blockade failure. In this study, we designed an intraneedle ultrasound (INUS) system and validated its efficacy in identifying anatomic structures relevant to thoracic region anesthesia. The 20-MHz INUS transducer comprised a single lead magnesium niobate-lead titanate crystal, and gain was set to 20 dB. It fit into a regular 18G needle and emitted radiofrequency-mode ultrasound signals at 1 mm from the needle tip. One hundred intercostal punctures were performed in 10 piglets. Intercostal spaces were identified by surface ultrasound or palpation and located by inserting and advancing the INUS transducer needle until the appropriate anatomy was identified. Blockade success was defined by ideal saline and dye spreading and confirmed by dissection. The pleura had a distinctive ultrasound signal, and successful detection of the intercostal muscles, endothoracic fascia and double-layered parietal and visceral pleura was achieved in all 100 puncture attempts. INUS allows real-time identification of intercostal structures and facilitates successful intercostal nerve blocks.

Neurotoxicity of perineural vs intraneural-extrafascicular injection of liposomal bupivacaine in the porcine model of sciatic nerve block

Liposomal bupivacaine is a prolonged-release local anaesthetic, the neurotoxicity of which has not yet been determined. We used quantitative histomorphometric and immunohistochemical analyses to evaluate the neurotoxic effect of liposomal bupivacaine after perineural and intraneural (extrafascicular) injection of the sciatic nerve in pigs. In this double-blind prospective randomised trial, 4 ml liposomal bupivacaine 1.3% was injected either perineurally (n = 5) or intraneurally extrafascicularly (n = 5). Intraneural-extrafascicular injection of saline (n = 5) was used as a control. After emergence from anaesthesia, neurological examinations were conducted over two weeks. After harvesting the sciatic nerves, no changes in nerve fibre density or myelin width indicative of nerve injury were observed in any of the groups. Intraneural injections resulted in longer sensory blockade than perineural (p < 0.003) without persistent motor or sensory deficit. Sciatic nerve block with liposomal bupivacaine in pigs did not result in histological evidence of nerve injury.

Interventional modalities to treat cancer-related pain

Cancer-related pain is a significant cause of morbidity in those affected by both primary and metastatic disease. Although oral, transdermal, and parenteral opioid medications are an integral part of the World Health Organization's analgesic ladder, their use may be limited by side effects. Fortunately, there are advanced interventional pain management strategies effective in reducing pain in the cancer patient while mitigating the aforementioned side effects. Celiac plexus blocks and neurolysis have been proven effective in treating cancers of the abdominal viscera (ie, pancreas). Transversus abdominis plane blocks, neurolysis, and catheter placement can be used to treat cancer pain associated with the abdominal wall. Peripheral nerve blocks and catheter placement at the brachial and lumbosacral plexus or peripheral nerves treat cancer pain associated with the upper and lower limbs, whereas paravertebral and intercostal blocks treat cancer pain associated with the chest wall and ribs. Finally, alternate drug delivery methods such as intrathecal drug delivery systems concentrate medication at central opioid receptors without affecting the peripheral receptors implicated in unwanted side effects. This article provides an overview of these interventions, including indications, contraindications, and potential complications of advanced interventional pain management options available for the treatment of intractable cancer-related pain.