Continuous Peripheral Nerve Blocks

Continuous femoral nerve block as pain management following total knee arthroplasty: a systematic review

INTRODUCTION

The present systematic review evaluated the current level of I evidence on continuous femoral nerve block (FNB) as pain management following total knee arthroplasty (TKA), comparing different drugs.

MATERIALS AND METHODS

This study followed the 2020 PRISMA guidelines. PubMed, Embase and Web of Science were accessed in November 2024. All clinical studies concerning continuous FNB for pain management following TKA were considered.

RESULTS

Data from 22 RCTs were retrieved. The drugs included in the analyses were levobupivacaine, bupivacaine and ropivacaine in isolation or combined with prilocaine or dexmedetomidine. A statistically significant difference was found in VAS at rest in postoperative day (POD) 0 (p < 0.01): the bupivacaine group demonstrated the highest values, and the ropivacaine combined with dexmedetomidine group had the lowest values. No other statistically significant difference in VAS at rest was found for any group in POD 1, 2, and 3 (p = 0.1, p = 0.1, and p = 0.4, respectively). The groups receiving ropivacaine combined with dexmedetomidine and prilocaine had the lowest values of VAS during activity in POD2 (p < 0.01), while in POD3 the groups receiving ropivacaine combined with prilocaine and the bupivacaine one had the lowest values (p < 0.01). No significant difference was found in VAS during activity between any group in POD 0 (p = 0.4) and POD 1 (p = 0.3).

CONCLUSION

Ropivacaine combined with dexmedetomidine might be the best compound for continuous femoral nerve block to manage pain following TKA during the first PODs. Further high-quality investigations are necessary to validate these findings in clinical settings.

Effect of dexmedetomidine combined with ropivacaine block on flap blood flow and patient satisfaction after flap transfer for hand trauma: a randomized controlled trial

The purpose of this study was to assess the effect of dexmedetomidine as a local anaesthetic adjuvant on flap blood flow and patient satisfaction regarding postoperative analgesia anterolateral thigh free flap transfer for hand trauma. A total of 66 patients were randomized into two groups. One group was treated with intermittent 1.0 µg/mL dexmedetomidine + 0.125% ropivacaine bolus at 8 mL/2 h and the other with intermittent 0.2% ropivacaine bolus at 8 mL/2 h, administered via continuous infraclavicular brachial plexus block. Dexmedetomidine had no significant effect on the flap blood supply and had a good safety profile. Moreover, 1.0 µg/mL dexmedetomidine + 0.125% ropivacaine provided similar satisfactory postoperative analgesia as 0.2% ropivacaine (p > 0.05), reduced hand numbness and motor block, and improved patient satisfaction (p < 0.05). All the flaps in the dexmedetomidine + ropivacaine group and 30 of 31 flaps in the ropivacaine group survived. The addition of dexmedetomidine to the local anaesthetic infusion appears to be a safe method of improving postoperative symptoms.Level of evidence:I.

Percutaneous auricular neuromodulation for postoperative analgesia

INTRODUCTION

Postoperative pain is often severe, with many patients still experiencing significant pain upon discharge. While opioids are effective for pain relief, they have numerous side effects and carry a high risk for misuse and dependence. Auricular electric stimulation, a form of neuromodulation, offers a promising alternative by electrically stimulating nerves of the auricle to modulate central pain pathways, potentially reducing postoperative pain and opioid requirements.

AREAS COVERED

This review, based on a search of the MEDLINE/PubMed, Scopus, and Cochrane review online sources from 1980 to 2024, discusses the use of auricular electric stimulation as a form of neuromodulation for management of postoperative pain focusing on the available evidence and future avenues for research.

EXPERT OPINION

Percutaneous auricular nerve stimulation offers a promising neuromodulation technique for managing postoperative pain. By modulating central pain processing through peripheral stimulation, this approach may reduce pain during recovery. Small pilot studies have suggested that auricular stimulation may lower pain intensity and reduce opioid consumption after surgery; however, further research is needed regarding both potential benefits and risks. As a minimally invasive technique, percutaneous auricular stimulation may provide a valuable adjunct to multimodal analgesia, especially in patients at risk of opioid-related complications.

Indocyanine green-mediated photothermal release of lidocaine from genipin-crosslinked gelatin hydrogel in nerve block

Local anesthetic (LA)-induced peripheral nerve block (PNB) is an important part of multimodal analgesia to reduce postoperative pain, accelerate postoperative recovery, and improve clinical prognosis. The duration of LA depends on anesthetics, and the repeated nerve positioning, puncture injection or indwelling catheter is often required to prolong the effect of PNB. In this study, the genipin, was used to crosslink gelatin-based hydrogel, and then co-loaded with indocyanine green (ICG) and lidocaine as an LA-controlled release system (ICG@Lido/Gel and ICG@Lido/gGel). The viscosity of the genipin-crosslinked gelatin hydrogel (gGel) could be controlled by the genipin/gelatin ratio to achieve the slow release of lidocaine. The ICG@Lido/Gel and ICG@Lido/gGel were biocompatible, and could reduce the instant concentration of lidocaine to minimize its direct cytotoxicity. The ICG@Lido/Gel and ICG@Lido/gGel could increase the PNB period to 70.8 min and 77.8 min, respectively. After NIR exposure, the PNB was introduced again and sustained to 20.8 min for ICG@Lido/Gel and 31.7 min for ICG@Lido/gGel. Therefore, the ICG@Lido/gGel could significantly prolong the PNB duration via increasing the residence time of lidocaine at the injection site, slowing the lidocaine release, and triggering the lidocaine release by NIR exposure. The ICG@Lido/gGel may expresses potential as a photothermal-triggered release system for PNB.

Analgesic Efficacy of Repeated Daily Injections Versus Continuous Adductor Canal Block After Total Knee Arthroplasty: An Open-Label, Randomized Clinical Trial

BACKGROUND

Total knee arthroplasty is frequently associated with postoperative pain. Continuous adductor canal blocks are widely used for postoperative analgesia. However, the high dislocation rate of nerve block catheters often leads to ineffective pain control. This study aimed to compare the analgesic effectiveness of repeated daily injections of adductor canal block up to postoperative day (POD) 2 and continuous adductor canal block in patients who underwent total knee arthroplasty.

METHODS

Seventy-six patients who underwent total knee arthroplasty under spinal anesthesia were randomized to receive repeated daily adductor canal blocks at the end of surgery and in the morning of POD1 and POD2 (n = 39) or continuous adductor canal block with a patient-controlled bolus (n = 37). All patients received perioperative multimodal analgesia. The primary outcome was the time-weighted average numeric rating scale pain score at rest, measured from the end of surgery to 14:00 on POD2. Pain scores over time were also compared using generalized estimating equations.

RESULTS

There was no significant difference in the time-weighted average pain score at rest (from POD0 to POD2) between the repeated injection group (2.9 ± 1.9) and the continuous group (3.1 ± 2.1; mean difference 0.09, 95% confidence interval [CI], -0.81 to 0.99; P = .842). Repeated daily injections did not reduce pain at rest or pain during movement after adjusting for time. In the continuous group, the cumulative occurrence of nerve block catheter dislocation was 48.6% (18/37) on POD1 and 62.2% (23/37) on POD2, as assessed using ultrasonography.

CONCLUSIONS

This study was unable to determine whether repeated daily injections or continuous adductor canal block provided superior analgesia in terms of the average pain score during the first 2 days after total knee arthroplasty. However, considering the high dislocation rate of nerve block catheters, reducing catheter dislodgement may improve the analgesic effectiveness of continuous adductor canal blocks.

Advanced Hydrogel Systems for Local Anesthetic Delivery: Toward Prolonged and Targeted Pain Relief

Local anesthetics (LAs) have been indispensable in clinical pain management, yet their limitations, such as short duration of action and systemic toxicity, necessitate improved delivery strategies. Hydrogels, with their biocompatibility, tunable properties, and ability to modulate drug release, have been extensively explored as platforms for enhancing LA efficacy and safety. This narrative review explores the historical development of LAs, their physicochemical properties, and clinical applications, providing a foundation for understanding the integration of hydrogels in anesthetic delivery. Advances in thermoresponsive, stimuli-responsive, and multifunctional hydrogels have demonstrated significant potential in prolonging analgesia and reducing systemic exposure in preclinical studies, while early clinical findings highlight the feasibility of thermoresponsive hydrogel formulations. Despite these advancements, challenges such as burst release, mechanical instability, and regulatory considerations remain critical barriers to clinical translation. Emerging innovations, including nanocomposite hydrogels, biofunctionalized matrices, and smart materials, offer potential solutions to these limitations. Future research should focus on optimizing hydrogel formulations, expanding clinical validation, and integrating advanced fabrication technologies such as 3D printing and artificial intelligence-driven design to enhance personalized pain management. By bridging materials science and anesthetic pharmacology, this review provides a comprehensive perspective on current trends and future directions in hydrogel-based LA delivery systems.

Socioeconomic disparities and trends in the utilization of regional and neuraxial anesthesia for pediatric femur fracture repair

Pediatric femur fractures often necessitate surgical intervention, with pain management being critical for both immediate and long-term outcomes. Peripheral nerve blocks (PNBs) and neuraxial techniques are effective in providing targeted pain relief while minimizing systemic opioid exposure. Despite their benefits, the utilization of these anesthesia techniques in pediatric orthopedic surgeries is limited, particularly among socioeconomically disadvantaged patients. This study aims to evaluate the association between socioeconomic status (SES) and the use of regional and neuraxial anesthesia in pediatric femur fracture repairs, focusing on healthcare resource utilization (HRU) outcomes such as hospital length of stay (LOS), total hospital charges, and discharge disposition. Using the 2016-2020 NIS database, we identified 43,605 pediatric patients who underwent femur fracture repair. Only 1 % received PNB, and 0.1 % received spinal block (SB). Our analysis revealed that PNB was less likely to be administered to patients from lower SES backgrounds, those with subtrochanteric fractures, or those requiring delayed repair. Conversely, PNB was associated with reduced HRU, while SB was linked to increased HRU. The findings underscore significant disparities in the application of regional anesthesia, influenced by socioeconomic factors. Our study highlights the need for standardized guidelines and interventions to address these disparities, ensuring equitable access to effective pain management techniques in pediatric orthopedic care. Further research is warranted to understand the barriers to the utilization of PNB and to develop strategies to enhance its adoption, particularly among underserved populations.

Principles of the Orthogeriatric Model of Care: A Primer

It is well known that over the last few decades, there has been significant growth of the aging population worldwide and especially in Europe, with an increase of more than two years per decade since the 1960's. Currently, in Europe, people aged over 65 years old represent 20% of the population, creating many new and complex challenges for national healthcare systems. In many countries, geriatric medicine is an established medical specialty, integrated into the primary and secondary care of the older population. In some countries, such as Portugal, specialist training in geriatric medicine is not available, even though the life-expectancy in Portugal is currently 81 years due to a decrease in fertility and mortality, and people aged over 60 currently represent nearly a third of the population. There is strong evidence in the medical literature that a fracture following a fall, and especially a neck of femur fracture, is one of the most serious events that can happen in an older person's lifetime. These fractures have been associated with increased morbidity, loss of independence, a high rate of institutionalization, and mortality. Rates of mortality after a year from femoral fractures have been proven to be three to four times higher than the expected in the general population, ranging between 15% to 36%. This emphasizes the importance of developing well-organized care pathways for these patients, which combine specialized geriatric care (also known as orthogeriatric care). This narrative review will focus on the core principles of orthogeriatric care and how medical professionals, including those who are not specialized in geriatric care, can effectively use them.

A Narrative Review of Ultrasound-Guided and Landmark-based Percutaneous Cryoneurolysis for the Management of Acute and Chronic Pain

PURPOSE OF REVIEW

Cryoneurolysis refers to the process of reversibly ablating peripheral nerves with extremely cold temperatures to provide analgesia for weeks to months. With ultrasound-guidance or landmark-based techniques, it is an effective modality for managing both acute and chronic pain. In this review, we summarize the reported literature behind its potential applications and efficacy.

RECENT FINDINGS

Here, we summarize several studies (from case reports to clinical trials) describing the use of ultrasound-guided and landmark-based cryoneurolysis for acute and chronic pain. Acute pain indications included pain related to knee arthroplasty, limb amputations, mastectomies, shoulder surgery, rib fractures, and burn. Chronic pain indications included chronic knee pain (due to osteoarthritis), shoulder pain, painful neuropathies, postmastectomy pain syndrome, phantom limb pain, facial pain/headaches, foot/ankle pain, inguinal pain, and sacroiliac joint pain. For both acute and chronic pain indications, more high quality randomized controlled clinical trials are needed to definitively assess the efficacy of cryoneurolysis versus other standard therapies for a multitude of pain conditions.

S-ketamine Infusion on Chronic Postoperative Pain Following Breast Cancer Surgery: A Randomized Double-Blind Placebo-Controlled Trial

BACKGROUND

Chronic postoperative surgical pain (CPSP) is a frequent complication following breast surgery and poses a challenge in terms of treatment. We hypothesized that the incidence of CPSP would be reduced at 3 months post-breast surgery with the administration of S-ketamine compared to a placebo.

PATIENTS AND METHODS

Participants were recruited and randomly assigned to either the S-ketamine group (S) or the control group (C). In group S, S-ketamine was administered as a 1.5 mg kg-1 bolus followed by 2 mg kg-1h-1 infusion, while in group C, a placebo of 0.9% saline was administered in the same volume and rate as S-ketamine. The primary outcome was the incidence of CPSP, measured using a 0-10 numeric rating scale (NRS), at 3 months postsurgery.

RESULTS

A total of 72 patients scheduled for mastectomy were enrolled (group S, n = 33; group C, n = 32). The incidence of CPSP at 3 months postsurgery was significantly lower in group S compared to group C (18.2% vs. 48.3%, P < .05). There was no statistical difference between the 2 groups in terms of the incidence of moderate to severe pain. NRS scores for postoperative pain at rest and during movement were significantly lower at 4 h and 24 h post-surgery (P < .05, respectively). Patients in Group S had lower Patient Health Questionnaire-9 (PHQ-9) scores at one week and 3 months post-surgery compared to Group C (P < .05, respectively).

CONCLUSION

S-ketamine infusion reduces the incidence of CPSP 3 months after breast surgery.

Defining the optimal local anaesthetic infusion regimen for erector spinae plane block catheters: the devil is in the details

Ni Eochagain and colleagues report that programmed intermittent bolus and continuous infusion regimens in continuous erector spinae plane (ESP) block catheters produced similar quality of recovery (QoR-15) scores, pain scores, and use of rescue opioids after video-assisted thoracic surgery. This is a reassuring finding for practitioners without access to pumps with programmed intermittent bolus functionality. Nevertheless, it remains plausible that the benefit of one regimen over another might vary depending on the specific infusion parameters. There continues to be scope for research into optimising programmed intermittent bolus delivery and dosing regimens and identifying the most appropriate clinical applications for this mode of infusion.

Efficacy of locoregional analgesic techniques after laparotomy for gynecologic cancer: a systematic review

OBJECTIVE

To determine which locoregional techniques are effective in managing post-operative pain in major open oncologic gynecologic surgery in terms of pain scores and opioid consumption when epidural analgesia is not a feasible option.

METHODS

A systematic review of the literature, based on the Preferred Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, was conducted. The ROB-2 assessment was used to assess bias. The primary outcomes were opioid consumption and post-operative pain scores. Secondary outcomes included post-operative markers such as time to mobilization and bowel movement.

RESULTS

A total of nine studies (n=714) were included in the analysis. Eight studies had a low risk of bias. Five different forms of locoregional analgesia were described. Eight studies compared with placebo and one study compared rectus sheath block with epidural analgesia. Three of the five studies investigating transversus abdominis plane (TAP) blocks showed an improvement in pain scores and opioid consumption when compared with the placebo group. One study investigating rectus sheath blocks and another investigating paravertebral blocks demonstrated significantly less opioid consumption and improved pain scores at certain time points. The studies investigating continuous wound infiltration and superior hypogastric plexus block found no significant effect. No adverse effects of locoregional anesthesia were found.

CONCLUSION

Our study showed that TAP blocks, rectus sheath blocks, and paravertebral blocks may decrease opioid consumption and improve pain scores in patients undergoing open abdominal surgery for gynecologic cancer. Additionally, these techniques might serve as a viable alternative for patients with contraindications to epidural analgesia.

Bedside percutaneous cryoneurolysis technique for management of acute rib fracture pain in adult trauma patients

Background

Acute pain due to rib fractures causes significant in-hospital morbidity and impacts patients' quality of life after discharge. Intraoperative transthoracic cryoneurolysis of the intercostal nerves can improve postoperative pain; however, non-surgical patients are provided limited analgesia options. Here, we describe our experience with a bedside cryoanalgesia technique for management of acute rib fracture pain.

Methods

Five patients at a single level I trauma center completed bedside intercostal nerve cryoneurolysis (INC) using a handheld cryotherapy device and ultrasound guidance. Relative pain ratings (scale 0-10/10) and maximal incentive spirometry (ISmax) volumes were taken prior to the procedure as a baseline. Patients were observed for 24 hours after procedure, with relative pain ratings and ISmax recorded at 1, 8, 16, and 24 hours after procedure.

Results

Our patients were 29-88 years old and had one to five single-sided rib fractures. At baseline, they had high pre-procedure pain ratings (7-10/10) and ISmax volumes of 800-2000 mL. Many had improvements in their pain rating but little change in their ISmax at 1 hour (1-5/10 and 1000-2000 mL, respectively) and 8 hours (1-5/10 and 1250-2400 mL, respectively). ISmax volumes improved by 16 hours (1500-2400 mL) with comparable pain ratings (0-5/10). At 24 hours, pain ratings and ISmax ranged from 0 to 8/10 and from 1500 mL to 2400 mL, respectively. Each patient had improved pain control and ISmax volumes compared with their pre-procedure values. All patients reported the procedure as an asset to their recovery at discharge.

Conclusions

Our study demonstrates patients with rib fractures may experience improved pain ratings and ISmax values after INC. Percutaneous INC appears to be a viable adjunct to multimodal pain control for patients with rib fractures and should be considered in patients with difficult pain control. Further studies are required to fully assess INC safety, efficacy, post-discharge outcomes, and utility in patients with altered mental status or on mechanical ventilation.

Level of evidence

Level V, case series.

Ultrasound-guided erector spinae plane block for postoperative analgesia in patients undergoing minimally invasive direct coronary artery bypass surgery: a double-blinded randomized controlled trial

PURPOSE

Minimally invasive direct coronary artery bypass (MIDCAB) surgery is associated with significant postoperative pain. We aimed to investigate the efficacy of ultrasound-guided erector spinae plane block (ESPB) for analgesia after MIDCAB.

METHODS

We conducted randomized controlled trial in 60 patients undergoing MIDCAB who received either a single-shot ESPB with 30 mL of ropivacaine 0.5% (ESPB group, n = 30) or normal saline 0.9% (control group, n = 30). The primary outcome was numerical rating scale (NRS) pain scores at rest within 48 hr postoperatively. The secondary outcomes included postoperative NRS pain scores on deep inspiration within 48 hr, hydromorphone consumption, and quality of recovery-15 (QoR-15) score at 24 and 48 hr.

RESULTS

Compared with the control group, the ESPB group had lower NRS pain scores at rest at 6 hr (estimated mean difference, -2.1; 99% confidence interval [CI], -2.7 to -1.5; P < 0.001), 12 hr (-1.9; 99% CI, -2.6 to -1.2; P < 0.001), and 18 hr (-1.2; 99% CI, -1.8 to -0.6; P < 0.001) after surgery. The ESPB group also showed lower pain scores on deep inspiration at 6 hr (-2.9; 99% CI, -3.6 to -2.1; P < 0.001), 12 hr (-2.3; 99% CI, -3.1 to -1.5; P < 0.001), and 18 hr (-1.0; 99% CI, -1.8 to -0.2; P = 0.01) postoperatively. Patients in the ESPB group had lower total intraoperative fentanyl use, lower 24-hr hydromorphone consumption, a shorter time to extubation, and a shorter time to intensive care unit (ICU) discharge.

CONCLUSION

Erector spinae plane block provided early effective postoperative analgesia and reduced opioid consumption, time to extubation, and ICU discharge in patients undergoing MIDCAB.

TRIAL REGISTRATION

www.chictr.org.cn (ChiCTR2100052810); registered 5 November 2021.

Continuous Catheter Techniques

Continuous peripheral nerve block catheters are simple in concept: percutaneously inserting a catheter adjacent to a peripheral nerve. This procedure is followed by local anesthetic infusion via the catheter that can be titrated to effect for extended anesthesia or analgesia in the perioperative period. The reported benefits of peripheral nerve catheters used in the surgical population include improved pain scores, decreased narcotic use, decreased nausea/vomiting, decreased pruritus, decreased sedation, improved sleep, and improved patient satisfaction.

Ultrasound‑guided erector spinae plane block in posterior lumbar surgery (Review)

The erector spinae plane block (ESPB) is a novel fascial planar block technique, which is used to reduce postoperative pain in several surgical procedures, including breast, thoracic, spine and hip surgery. Due to its recognizable anatomy and low complication rate, the application of ESPB has been significantly increased. However, it is rarely used in clinical practice for postoperative analgesia after posterior lumbar spine surgery, while the choice of adjuvant drugs, block levels and drug doses remain controversial. Based on the current literature review, ropivacaine and dexmedetomidine could be considered as the best available drug combination. The present review aimed to analyze the currently available clinical evidence and summarize the benefits and challenges of ESPB in spinal surgery, thus providing novel insights into the application of ESPB in the postoperative management of posterior lumbar surgery.

Local anesthetic delivery systems for the management of postoperative pain

Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs), including amide-type LAs, ester-type LAs, and other potential ion-channel blockers, are emerging as drugs for POP management because of their effectiveness and affordability. However, LAs typically exhibit short durations of action and prolonging the duration by increasing their dosage or concentration may increase the risk of motor block or systemic local anesthetic toxicity. In addition, techniques using LAs, such as intrathecal infusion, require professional operation and are prone to catheter displacement, dislodgement, infection, and nerve damage. With the development of materials science and nanotechnology, various LAs delivery systems have been developed to compensate for these disadvantages. Numerous delivery systems have been designed to continuously release a safe dose in a single administration to ensure minimal systemic toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia according to changes in the external trigger conditions, achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this review, we summarize POP pathways, animal models and methods for POP testing, and highlight LAs delivery systems for POP management. STATEMENT OF SIGNIFICANCE: Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs) are emerging as drugs for POP management because of their effectiveness and affordability. However, they exhibit short durations and toxicity. Various LAs delivery systems have been developed to compensate for these disadvantages. They have been designed to continuously release a safe dose in a single administration to ensure minimal toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia to achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this paper, we summarize POP pathways, animal models, and methods for POP testing and highlight LAs delivery systems for POP management.

Single-bolus injection of local anesthetic, with or without continuous infusion, for interscalene brachial plexus block in the setting of multimodal analgesia: a randomized controlled unblinded trial

INTRODUCTION

Previous trials favored a continuous interscalene brachial plexus block over a single injection for major shoulder surgery. However, these trials did not administer a multimodal analgesic regimen. This randomized, controlled unblinded trial tested the hypothesis that a continuous infusion of local anesthetic for an interscalene brachial plexus block still provides superior analgesia after major shoulder surgery when compared with a single injection in the setting of multimodal analgesia, inclusive of intravenous dexamethasone, magnesium, acetaminophen and ketorolac.

METHODS

Sixty patients undergoing shoulder arthroplasty or arthroscopic rotator cuff repair were randomized to receive a bolus of ropivacaine 0.5%, 20 mL, with or without a continuous infusion of ropivacaine 0.2% 4-8 mL/hour, for an interscalene brachial plexus block. Patients were provided with intravenous morphine patient-controlled analgesia. The primary outcome was cumulative intravenous morphine consumption at 24 hours postoperatively. Secondary outcomes included pain scores at rest and on movement, and functional outcomes, measured over 48 hours after surgery.

RESULTS

Median (IQR) cumulative intravenous morphine consumption at 24 hours postoperatively was 10 mg (4-24) in the continuous infusion group and 14 mg (8-26) in the single injection group (p=0.74). No significant between-group differences were found for any of the secondary outcomes.

CONCLUSIONS

A continuous infusion of local anesthetic for an interscalene brachial plexus block does not provide superior analgesia after major shoulder surgery when compared with a single injection in the setting of multimodal analgesia, inclusive of intravenous dexamethasone, magnesium, acetaminophen and ketorolac. The findings of this study are limited by performance and detection biases.

TRIAL REGISTRATION NUMBER

NCT04394130.

Evaluation and Treatment of Entrapped Peripheral Nerve Catheters: A Case Report and Review

Methods to remove retained peripheral nerve catheters range from non-invasive techniques to open surgical procedures. This study reviews two cases requiring surgical intervention for catheter remnant removal after catheter breakage and presents a systematic review describing the diagnosis and treatment of retained perineural catheters. While still very rare, our case report and systematic review demonstrate that retained nerve catheters can occur as the result of kinking or knotting, but also from catheter breakage. We recommend risk mitigation strategies for providers placing or caring for patients with regional nerve catheters.

Dexamethasone versus Dexmedetomidine as Adjuvants in Ultrasound Popliteal Sciatic Nerve Block for Hallux Valgus Surgery: A Mono-Centric Retrospective Comparative Study

Background and Aim

Ultrasound popliteal sciatic nerve block (UPSNB) is commonly performed in foot and ankle surgery. This study aims to assess the use of dexmedetomidine and dexamethasone as adjuvants in UPSNB for hallux valgus (HV) surgery, comparing their efficacy in producing motor and sensory block and controlling postoperative pain. The adverse event rate was also evaluated.

Methods

This mono-centric retrospective study included 62 adult patients undergoing HV surgery: 30 patients received lidocaine 2% 200 mg, ropivacaine 0.5% 50 mg and dexamethasone 4 mg (Group 1), whereas 32 patients received lidocaine 2% 200 mg, ropivacaine 0.5% 50 mg, and dexmedetomidine 1 mcg/Kg (Group 2). At first, the visual analogue scale (VAS) was evaluated after 48 hours. The other outcomes were time to motor block regression, evaluation of the first analgesic drug intake, analgesic effect, adverse effects (hemodynamic disorders, postoperative nausea and vomiting (PONV)) and patient satisfaction. The continuous data were analyzed with student's t-test and the continuous one with χ2. Statistical significance was set at a p-value lower than 0.05.

Results

No significant difference was found in VAS after 48 hours (4.5 ± 1.6 vs 4.7 ± 1.7, p = 0.621) to motor block regression (18.9 ± 6.0 vs 18.7 ± 6, p = 0.922). The number of patients that took their first analgesic drug in the first 48 h (p = 0.947 at 6 hours; p = 0.421 at 12 hours; p = 0.122 at 24 hours and p = 0.333 at 48 hours) were not significant. A low and similar incidence of intraoperative hemodynamic disorders was recorded in both groups (hypotension p = 0.593; bradycardia p = 0.881). Neither PONV nor other complication was found. Patients in Group 1 reported a lower degree of interference with sleep (p = 0.001), less interference with daily activities (P = 0.002) and with the affective sphere (P = 0.015) along with a more satisfactory postoperative pain management (p < 0.001) as compared to Group 2.

Conclusion

No significant differences were observed in the duration of motor and sensory blockade between patients in both groups. Additionally, both groups showed good pain control with a low rate of adverse effects, even if there was no clinical difference between the groups. However, patients who received dexamethasone reported experiencing less interference with their sleep, daily activities and overall emotional well-being, and overall pain control.

Dislodgment of continuous suprascapular nerve block catheters after physiotherapy: A cadaver study

BACKGROUND

Continuous peripheral nerve blocks are commonly used for pain management. However, the incidence of catheter dislodgement or migration is unclear, and may be underestimated and underreported. Our objective was to assess suprascapular catheter tip positioning before and after routine simulated shoulder physiotherapy manipulation in an anatomical cadaver model.

METHOD

Eight ultrasound-guided continuous suprascapular nerve block catheters were placed in cryopreserved fresh cadavers. Computed tomography (CT) confirmed the location of the catheter tip after injection of 1 ml of contrast medium. We performed a series of standardized shoulder movements during a simulated shoulder physiotherapy session in cadavers. Following this, we administered 1 ml of methylene blue through the catheters, and then performed anatomical dissections to accurately identify the location of the catheter tips and compare them to their placement prior to the 'physiotherapy'.

RESULT

CT imaging confirmed the location of the catheter tips at the suprascapular notch in all cases. However, following physiotherapy, 2 catheters (25%) were found to have migrated - specifically, 1 was located in the supraspinatus muscle, and the other was located in the trapezius muscle.

CONCLUSION

Our findings suggest that catheter dislodgement may occur in approximately 25% of cases following simulated physiotherapy manipulation. However, further research is needed to determine the read incidence of catheter dislodgement in clinical practice.

Continuous stellate ganglion block for ventricular arrhythmias: case series, systematic review, and differences from thoracic epidural anaesthesia

AIMS

Percutaneous stellate ganglion block (PSGB) through single-bolus injection and thoracic epidural anaesthesia (TEA) have been proposed for the acute management of refractory ventricular arrhythmias (VAs). However, data on continuous PSGB (C-PSGB) are scant. The aim of this study is to report our dual-centre experience with C-PSGB and to perform a systematic review on C-PSGB and TEA.

METHODS AND RESULTS

Consecutive patients receiving C-PSGB at two centres were enrolled. The systematic literature review follows the latest Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Our case series (26 patients, 88% male, 60 ± 16 years, all with advanced structural heart disease, left ventricular ejection fraction 23 ± 11%, 32 C-PSGBs performed, with a median duration of 3 days) shows that C-PSGB is feasible and safe and leads to complete VAs suppression in 59% and to overall clinical benefit in 94% of cases. Overall, 61 patients received 68 C-PSGBs and 22 TEA, with complete VA suppression in 63% of C-PSGBs (61% of patients). Most TEA procedures (55%) were performed on intubated patients, as opposed to 28% of C-PSGBs (P = 0.02); 63% of cases were on full anticoagulation at C-PSGB, none at TEA (P < 0.001). Ropivacaine and lidocaine were the most used drugs for C-PSGB, and the available data support a starting dose of 12 and 100 mg/h, respectively. No major complications occurred, yet TEA discontinuation rate due to side effects was higher than C-PSGB (18 vs. 1%, P = 0.01).

CONCLUSION

Continuous PSGB seems feasible, safe, and effective for the acute management of refractory VAs. The antiarrhythmic effect may be accomplished with less concerns for concomitant anticoagulation compared with TEA and with a lower side-effect related discontinuation rate.

Arthroscopic assisted brachial plexus catheter placement: an alternative to the percutaneous interscalene approach

Background

Brachial plexus catheter placement at the interscalene level is beneficial for shoulder analgesia but presents logistical challenges due to the superficial nature of the plexus at this level, increased patient movement in the neck, and therefore higher likelihood for catheter dislodgement.

Methods

Patients requiring shoulder arthroscopy and suprascapular nerve decompression were identified. Under arthroscopic guidance, a catheter was placed percutaneously into the scalene medius muscle next to the suprascapular nerve and the upper trunk of the brachial plexus. Patients were followed postoperatively for perioperative analgesic outcomes.

Results

Ten patients were identified and consented for intraoperative brachial plexus catheter placement. Patient demographics and surgical details were determined. Postoperative adjunctive pain management and pain scores were variable. Two patients required catheter replacement using ultrasound guidance in the perioperative anesthesia care unit due to poorly controlled pain. There were no incidents of catheter failure due to dislodgement.

Discussion

This study presents the first description of arthroscopically-assisted brachial plexus catheter placement. This method may present an alternative to traditional ultrasound guided interscalene catheter placement. Further study is needed to determine if analgesic outcomes, block success, and dislodgement rates are improved with this method.

Ultrasound-Guided Percutaneous Cryoneurolysis for Perioperative Analgesia Following Major Lower Extremity Amputation: A Randomized, Participant- and Observer-Masked, Sham-Controlled Pilot Study

BACKGROUND

Extremity amputations are associated with pain in both the residual limb and the phantom limb. This pain, which is often debilitating, may be prevented by excellent perioperative pain control. Ultrasound-guided percutaneous cryoneurolysis is an analgesic modality offering pain control for weeks or months following surgery. This treatment has not been compared to the sham procedure for large nerves (e.g., femoral and sciatic) to provide preoperative analgesia. We therefore conducted a randomized, controlled pilot study to evaluate the use of this modality for the treatment of pain following amputation to (1) determine the feasibility of and optimize the study protocol for a subsequent definitive clinical trial; and (2) estimate analgesia and opioid reduction within the first postoperative weeks.

METHODS

A convenience sample of seven patients undergoing lower extremity amputation were randomized to receive either active cryoneurolysis or a sham procedure targeting the sciatic and femoral nerves in a participant-masked fashion. This was a pilot study with a relatively small number of participants, and therefore the resulting data were not analyzed statistically.

RESULTS

Compared to the participants who received sham treatment (n=3), those who underwent active cryoneurolysis (n=4) reported lower pain scores and decreased opioid consumption at nearly all time points between days one and 21 following amputation.

CONCLUSIONS

Ultrasound-guided percutaneous cryoneurolysis of the femoral and sciatic nerves prior to lower extremity amputation appears feasible and potentially effective. The data from this pilot study may be used to power a definitive randomized clinical trial.

Anterior quadratus lumborum catheters for elective cesarean section: A double-blind, randomized, placebo-controlled trial

BACKGROUND

Optimizing pain management following cesarean section is crucial for the well-being of both mother and infant. Various types of quadratus lumborum blocks have exhibited reduced opioid consumption and pain scores after cesarean section. However, duration of block effect is relatively short. The aim of this study was to investigate the analgesic efficacy of the anterior quadratus lumborum catheters for cesarean section.

METHODS

All 32 enrolled participants were allocated to postoperative bilateral ultrasound-guided anterior quadratus lumborum catheter placement with injection of 60 mL ropivacaine 0.375% after cesarean section. Randomization at 2 h resulted in either 60 mL ropivacaine 0.2% or 60 mL isotonic saline injected through the catheters, with subsequent 22-h infusion of either ropivacaine 0.2% or isotonic saline with an infusion rate of 4 mL h-1 per catheter. Participants in the active group received a total of 697 mg ropivacaine during the first 24 h. All participants received the standard postoperative multimodal pain regimen, and a final bilateral injection at 24-h post-catheter placement of 60 mL ropivacaine 0.375% in total. The primary outcome was time to first opioid administration. Secondary outcomes were pain scores, time to first ambulation, nausea and vomiting, accumulated opioid consumption, and catheter displacement rates.

RESULTS

No significant intergroup differences were observed following the randomized intervention. Median time to first opioid (IQR) was (active vs. placebo) 414 (283, 597) vs. 428 (245, 552) minutes, with a median difference (CI) of -14 (-184 to 262) min, p = .32.

CONCLUSION

Bilateral anterior quadratus lumborum catheters with continuous infusion did not prolong time to first opioid after elective cesarean section.

Liposomal bupivacaine for ultrasound-guided rectus sheath blocks after midline laparotomy

Optimal pain management after open abdominal surgery is essential but can be difficult to achieve. The effects of inadequate analgesia go beyond the first few postoperative days; severe acute postoperative pain may contribute to the development of chronic postsurgical pain. Thoracic epidural analgesia is a traditional approach to the management of acute pain after open abdominal surgery but has multiple possible contraindications and can be technically challenging. In our hospital, we typically offer ultrasound-guided rectus sheath blocks with catheters when epidural analgesia is not feasible. However, the recent registration of long-acting liposomal bupivacaine in the Netherlands as well as logistical and equipment-related issues have led us to consider liposomal bupivacaine as an alternative to the use of catheters. Here, we present a short case series to describe our first clinical experiences with the use of liposomal bupivacaine in ultrasound-guided rectus sheath blocks after midline laparotomy for three patients in whom epidural insertion was contraindicated.

Reconceptualizing Acute Pain Management in the 21st Century

Acute pain can have many etiologies that include surgical procedures, trauma (motor vehicle accident), musculoskeletal injuries (rib fracture) and, burns among others. Valuable components of a multimodal approach to acute pain management include both opioid and non-opioid medications, procedure specific regional anesthesia techniques (peripheral nerve blocks and neuraxial approaches), and interventional approaches (eg, peripheral nerve stimulation and cryo-neurolysis). Overall, successful acute perioperative pain management requires a multimodal, multidisciplinary approach that involves a coordinated effort between the surgical team, the anesthesia team, nursing, and pharmacy staff using Enhanced Recovery After Surgery (ERAS) protocols.

Comparative retrospective review of perioperative analgesia using ultrasound-guided programmed intermittent erector spinae plane block for video-assisted thoracoscopic lobectomy

BACKGROUND

The retrospective cohort study was conducted to estimate the opioid-sparing anesthesia and limited side-effects with ultrasound (US)-guided ESPB using programmed intermittent bolus (PIB) or continuous infusion (CI) and standard opioid-based anesthesia in patients undergoing video-assisted thoracoscopic lobectomy (VATS).

METHODS

Patients underwent VATS were stratified into either control group or one of the two ESPB groups in a 1:2:2 ratio depending on whether PIB was implemented or not. The primary endpoint was intra- and post-operative opioids consumption over the first 48 h following surgery.

RESULTS

A total of 180 cases were included in the analysis. Cumulative perioperative opioid administration was found to be significantly different between PIB, CI and control group (both p < 0.001), and between PIB and CI group (p = 0.028). More specifically, the mean was 305.30 ± 51.35 mg, 339.68 ± 56.07 mg and 468.91 ± 79.84 mg in PIB, CI and control group. NRS scores at rest across all postoperative times were comparable in two ESPB groups, while significantly lower than control group, however, scores during exercising at postoperative 3, 6, 12 h were significantly lower in PIB group as compared to CI group. A wider anesthetized dermatomes with PIB was observed at 6, 24 and 48 h as opposed to the CI. The mean of levobupivacaine plasma concentration was significantly lower for PIB at postoperative 0.5, 12, 24 and 48 h after initiation than CI. However, local anesthetic toxicity was not observed in any of the two ESPB groups.

CONCLUSIONS

When US-guided ESPB using PIB was performed preoperatively, it contributed to the minimization of intra- and post-operative opioid consumption due to better analgesia with a wider anesthetic dermatome opposed to conventional CI, whereas, it was also associated with lower risk of local anesthetic toxicity because of lower plasma concentration of levobupivacaine.

Intercostal cryonerve block versus elastomeric infusion pump for postoperative analgesia following surgical stabilization of traumatic rib fractures

OBJECTIVE

Patients with blunt thoracic trauma requiring surgical stabilization of rib fractures (SSRF) frequently experience severe pain. Further, a rising prevalence of opioid-tolerant patients sustain traumatic injuries. The optimal pain management adjunct for concurrent use with SSRF remains uncertain. This study compared outcomes in patients undergoing SSRF with concomitant cryonerve block (CryoNB) or ropivacaine 0.2% elastomeric infusion pump (EIP).

METHODS

A single-center retrospective comparative analysis was performed at a level II trauma center. A query of our institution's trauma registry of consecutive patients undergoing SSRF from October 2017 to November 2020 with either intercostal CryoNB or ropivacaine 0.2% EIP was conducted. Opioid consumption in oral morphine equivalents (OME), patient-reported pain scores by numerical rating scale, and pulmonary function measured by incentive spirometry effort (mL) were collected at baseline and on postoperative days 1-3. Results were analyzed using a linear-mixed-effects model. Length of stay (LOS), complications, and hospital charges were assessed as secondary outcomes.

RESULTS

Twenty-six patients meeting inclusion criteria were evaluated. Patient demographics, injury, and surgical variables were similar between groups. The estimated effect for patients treated with CryoNB (n = 14) compared to EIP (n = 12) demonstrated a 25% (estimated -1.37 OME, 95% CI, -2.411 to -0.335, p = 0.01) reduction in hospital opioid requirements, fewer discharge opioids (41.3 mg (37.5-45) versus 175 mg (150- 200), p = 0.03), 22% (estimated -1.506, 95% CI, -2.722 to -0.290, p = 0.02) reduction in pain scores, and shorter postoperative LOS (4 days (4-5) versus 6 days (5-9.5), p = 0.04). Pulmonary function (estimated -48.8 mL, 95% CI, -312.74 to 215.05, p = 0.71), total hospital costs (CryoNB: $90,224 ± 34,633; EIP: $131,498 ± 73,072, p = 0.07), and complications were no different between cohorts.

CONCLUSION

The addition of intercostal CryoNB as an adjunct to multimodal pain management in trauma patients undergoing surgical fixation of rib fractures may be of benefit. Based on our early data, this technique appears to be promising in reducing opioid requirements and providing an extended duration of pain control without increased costs or complications.

Perineural low dexamethasone dose as adjuvant in supraclavicular brachial plexus block for arteriovenous fistula creation in end stage renal disease: a randomized controlled trial

BACKGROUND AND AIMS

Dexamethasone as adjunct to local anesthetic solution improves the quality of brachial plexus block (BPB). However, evidence for its efficacy at low doses (< 4 mg) is lacking. This study was designed to evaluate the duration of analgesia attained with low dose dexamethasone as adjuvant to local anesthetic for creation of arteriovenous fistula (AVF) under BPB.

METHODS

Sixty-six patients scheduled for AVF creation were randomly allocated to receive either saline (control) or 2 mg dexamethasone, together with 0.5% ropivacaine and 0.2% lignocaine. The primary outcome was duration of analgesia, defined as time from performing the block to the first analgesic request. The secondary outcomes were time from injection to complete sensory block, time from injection to complete motor block, duration of motor block, postoperative analgesic consumption, and fistula patency at three months.

RESULTS

All the blocks were effective. In the group that received dexamethasone, the time to first analgesic request was significantly delayed (432 ± 43.8 minutes vs. 386.4 ± 40.2 minutes; p < 0.01). The onset of sensory and motor blockade occurred faster in dexamethasone group and overall analgesic consumption was also reduced. However, dexamethasone addition did not prolong the duration of motor block. There was no statistically significant difference in the patency of fistulas between the two groups at three months. (p = 0.34).

CONCLUSION

Addition of low-dose perineural dexamethasone to local anesthetic solution significantly prolonged the duration of analgesia. Further trials are warranted to compare the adverse effects between dexamethasone doses of 4 mg and lower.

Peripheral neuropathy associated with monomethyl auristatin E-based antibody-drug conjugates

Since the successful approval of gemtuzumab ozogamicin, antibody-drug conjugates (ADCs) have emerged as a pivotal category of targeted therapies for cancer. Among these ADCs, the use of monomethyl auristatin E (MMAE) as a payload is prevalent in the development of ADC drugs, which has significantly improved overall therapeutic efficacy against various malignancies. However, increasing clinical observations have raised concerns regarding the potential nervous system toxicity associated with MMAE-based ADCs. Specifically, a higher incidence of peripheral neuropathy has been reported in ADCs incorporating MMAE as payloads. Considering the increasing global use of MMAE-based ADCs, it is imperative to provide an inclusive overview of diagnostic and management strategies for this adverse event. In this review, we examine current information and what future research directions are required to better understand and manage this type of clinical challenge.

Pain relief after major ankle and hindfoot surgery with repetitive peripheral nerve blocks: A feasibility study

BACKGROUND

Major ankle and hindfoot surgery (e.g., ankle, triple and subtalar arthrodesis) typically causes severe postoperative pain, especially the first two postoperative days. Current modalities of postoperative analgesic treatment often include continuous peripheral nerve blocks of the saphenous and sciatic nerves via catheters in order to extend the duration of pain- and opioid-free nerve blockade to 48 h. Unfortunately, the 48 h-efficacy of continuous infusion via a catheter is reduced by a high displacement rate. We hypothesised that one-time repetition of the single injection peripheral nerve blocks would provide effective analgesia with a low opioid consumption the first 48 postoperative hours.

METHODS

Eleven subjects preoperatively received a popliteal sciatic and a saphenous single injection nerve block with a protracted local anaesthetic mixture. Surgery was performed under general anaesthesia. The one-time repetition of the single injection nerve block was carried out approximately 24 h after the primary nerve block. The main outcomes were pain and cumulative opioid consumption during the first 48 postoperative hours.

RESULTS

Nine of the 11 (82%) patients had effective analgesia without opioids during the first 48 postoperative hours. Two patients each required a single dose of 7.5 mg of oral morphine equivalents after 43 h.

CONCLUSION

One-time repetition of single injection saphenous and sciatic nerve blocks consistently provided effective analgesia practically without opioids for 48 h after major elective ankle and hindfoot surgery.

The Emerging Role of Peripheral Nerve Stimulation in Postoperative Analgesia

PURPOSE OF REVIEW

Though peripheral nerve stimulation has long been utilized in the field of chronic pain management, its use in acute pain management in the postoperative period is relatively novel and warrants further consideration.

RECENT FINDINGS

In the postsurgical period, peripheral nerve stimulation may offer an additional low-risk, opioid-sparing analgesic option, which is particularly pertinent in the setting of the ongoing opioid epidemic, as inadequate postsurgical analgesia has been shown to increase the risk of developing persistent or chronic postsurgical pain. In this review, we discuss the current literature that illustrate the emerging role of peripheral nerve stimulation as an effective treatment modality in the postoperative period for the management of acute pain, as various studies have recently been conducted evaluating the feasibility of utilizing percutaneous peripheral nerve stimulation as an adjunct in postsurgical analgesia. Nonetheless, future studies are necessary to continue to elucidate the short- and long-term impacts of peripheral nerve stimulation use in acute postsurgical analgesia.

Analgesic Trends in the Management of Pain Following Total Knee Arthroplasty: A Comparison of Peri-Articular Infiltration, Adductor Canal Block, and Adjuvant Treatment for Posterior Knee Pain

The rising number of total knee arthroplasties (TKA's) in the United States increases demand for perioperative pain modalities, which can promote early mobilization and discharge. Over the decades, a focus has shifted from opioid-dominant regimens to motor-sparing multimodal protocols, which have not only improved pain scores and reduced opioid consumption but also improved overall patient outcomes. In this article, we briefly review the evolution of post-operative pain management in patients undergoing TKA and summarize the literature on the most popular modalities currently used including periarticular injections, adductor canal blocks, distal selective nerve blocks, as well as liposomal bupivacaine as part of a multimodal approach.

Pain Management and Opioid Use with Long-Acting Peripheral Nerve Blocks for Hand Surgery: A Descriptive Study

Background

Peripheral nerve blocks (PNBs) are used in multiple surgical fields to provide a high level of regional pain relief with a favorable adverse effect profile. Peripheral nerve blocks aim to decrease overall perioperative pain and lower systemic analgesic requirements. Short-acting anesthetic agents are commonly given as single-injection PNBs for pain relief, typically lasting less than 24 hours. Liposomal bupivacaine is a newer anesthetic formulation lasting up to 72 hours as a single-injection PNB and may allow patients to recover postoperatively with a lower need for opioid analgesics.

Objectives

This study investigates peri- and postoperative pain and opioid use in patients receiving a long-acting brachial plexus PNB for hand surgery.

Methods

A retrospective review of patients who underwent a long-acting PNB using liposomal bupivacaine in the brachial plexus for minor hand operations was performed between July 2020 and May 2023 in Florida, USA. Patients were administered a ten-question survey regarding perioperative pain levels, post-operative symptoms, patient satisfaction, postoperative opioid use, and postoperative non-opioid analgesics.

Results

One hundred three patients, including 21 males and 82 females with an average age of 68.3 ± 15.8 years, completed a survey (34.2% response rate). Patients reported a considerable reduction in pain from 7.9 ± 2.2 out of ten before the PNB to 1.6 ± 1.8 in the perioperative period, 4.3 ± 2.7 in postoperative days zero to three, and 3.8 ± 2.4 in postoperative days four and five. Nerve block effects lasted a mean of 2.2 ± 2.0 days and patients reported a high level of satisfaction regarding their pain management plan with a score of 9.4 ± 1.4 out of ten. 20.4% of patients were prescribed opioids and 41.7% used NSAIDs postoperatively.

Conclusions

Liposomal bupivacaine PNBs effectively reduced peri- and postoperative pain with pain relief lasting 2.2 ± 2.0 days. Patients were highly satisfied with their pain management and there was a low rate of postoperative opioid prescription. Given these results, long-acting PNBs have the potential to significantly improve patient satisfaction, reduce anesthesia use, and reduce postoperative opioid prescription.

Continuous peripheral nerve blocks for analgesia following painful ambulatory surgery: a review with focus on recent developments in infusion technology

PURPOSE OF REVIEW

Continuous peripheral nerve blocks (cPNB) decrease pain scores and opioid consumption while improving patient satisfaction following ambulatory surgery. This review focuses on the history and evolution of ambulatory cPNBs, recent developments in infusion technology that may prolong the duration of analgesia, optimal choice of cPNB for various surgical procedures, and novel analgesic modalities that may prove to be alternatives or supplements to cPNBs.

RECENT FINDINGS

The primary factor limiting the duration of an ambulatory cPNB is the size of the local anesthetic reservoir. Recent evidence suggests the use of automated boluses, as opposed to continuous infusions, may decrease the rate of consumption of local anesthetic and, thereby, prolong the duration of analgesia. Utilizing a long-acting local anesthetic (e.g. ropivacaine) for initial block placement and an infusion start-delay timer may further increase this duration.

SUMMARY

Patients undergoing painful ambulatory surgery are likely to have less pain and require fewer opioid analgesics when receiving a cPNB for postoperative analgesia. Advances in electronic pumps used for cPNBs may increase the duration of these benefits.

Patient-centered results from a multicenter study of continuous peripheral nerve blocks and postamputation phantom and residual limb pain: secondary outcomes from a randomized, clinical trial

INTRODUCTION

We previously reported that a 6-day continuous peripheral nerve block reduces established postamputation phantom pain. To provide patients and providers with the information to best inform treatment decisions, here we reanalyze the data and present the results in a more patient-centered format. We also provide information on patient-defined clinically relevant benefits to facilitate evaluation of available studies and guide future trial design.

METHODS

The original trial enrolled participants with a limb amputation and phantom pain who were randomized to receive a 6-day continuous peripheral nerve block(s) of either ropivacaine (n=71) or saline (n=73) in a double-masked fashion. Here we calculate the percentage of each treatment group that experienced a clinically relevant improvement as defined by previous studies as well as present what the participants of our study defined as small, medium, and large analgesic improvements using the 7-point ordinal Patient Global Impression of Change scale.

RESULTS

Among patients who were given a 6-day ropivacaine infusion, 57% experienced at least a 2-point improvement on the 11-point numeric rating scale in their average and worst phantom pain 4 weeks postbaseline as compared with 26% (p<0.001) for average and 25% (p<0.001) for worst pain in patients given a placebo infusion. At 4 weeks, the percentage of participants rating their pain as improved was 53% for the active vs 30% for the placebo groups (95% CI 1.7 (1.1, 2.7), p=0.008). For all patients combined, the median (IQR) phantom pain Numeric Rating Scale improvements at 4 weeks considered small, medium, and large were 2 (0-2), 3 (2-5), and 5 (3-7), respectively. The median improvements in the Brief Pain Inventory interference subscale (0-70) associated with small, medium, and large analgesic changes were 8 (1-18), 22 (14-31), and 39 (26-47).

CONCLUSIONS

Among patients with postamputation phantom pain, a continuous peripheral nerve block more than doubles the chance of a clinically relevant improvement in pain intensity. Amputees with phantom and/or residual limb pain rate analgesic improvements as clinically relevant similarly to other chronic pain etiologies, although their smallest relevant improvement in the Brief Pain Inventory was significantly larger than previously published values.

TRIAL REGISTRATION NUMBER

NCT01824082.

Perineural dexmedetomidine in femoral nerve blocks increases the duration of postoperative analgesia for anterolateral thigh flap donor sites in patients with oral cancer

Although the duration of analgesia provided by a single-shot nerve block is limited, perineural dexmedetomidine significantly enhances nerve blocks during extremity surgery. This study aimed to investigate the role of dexmedetomidine added to ropivacaine in femoral nerve blocks for postoperative analgesia of the anterolateral thigh (ALT) flap donor site in patients with oral cancer. Fifty-two participants scheduled for maxillofacial tumor resection and reconstruction using an anterolateral thigh flap were randomly allocated to either the Ropi group (femoral nerve block with ropivacaine) or the Ropi + Dex group (femoral nerve block with ropivacaine plus dexmedetomidine). The primary outcome was the duration of the sensory block, while the secondary outcomes were 24 h postoperative sufentanil use, number of patients using rescue analgesics, vital signs, postoperative pain score, incidence of agitation, and presence of adverse effects. Dexmedetomidine plus ropivacaine significantly prolonged the duration of sensory block compared with ropivacaine alone (10.4 ± 0.9 h vs 14.0 ± 1.3 h; P < 0.001). Age was positively correlated with increased duration of sensory block (r = 0.300; P = 0.033). Postoperative pain scores at the donor sites were lower in the Ropi + Dex group than in the Ropi group, at 12 h after surgery (P < 0.001). Although there were no statistically significant differences in the incidence of bradycardia between the two groups, four patients treated with dexmedetomidine experienced episodes of bradycardia. Perineural dexmedetomidine prolonged the duration of femoral nerve block and reduced postoperative pain scores at the ALT flap donor sites in patients with oral cancer.

Pupillary Pain Index Predicts Postoperative Pain but Not the Effect of Peripheral Regional Anaesthesia in Patients Undergoing Total Hip or Total Knee Arthroplasty: An Observational Study

Background and Objectives: The pupillary pain index (PPI) allows the evaluation of intraoperative nociception by measuring pupillary reaction after a localized electrical stimulus. It was the objective of this observational cohort study to investigate the pupillary pain index (PPI) as a method to evaluate the fascia iliaca block (FIB) or adductor canal block (ACB) sensory areas during general anaesthesia in orthopaedic patients with lower-extremity joint replacement surgery. Materials and Methods: Orthopaedic patients undergoing hip or knee arthroplasty were included. After anaesthesia induction, patients received an ultrasound-guided single-shot FIB or ACB with 30 mL and 20 mL of 0.375% ropivacaine, respectively. Anaesthesia was maintained with isoflurane or propofol/remifentanil. The first PPI measurements were performed after anaesthesia induction and before block insertion, the second at the end of surgery. Pupillometry scores were evaluated in the area of the femoral or saphenous nerve (target) and C3 dermatome (control). Primary outcomes were differences between PPIs before and after peripheral block insertion as well as the relationship between PPIs and postoperative pain scores; secondary outcomes were the relationship between PPIs and opioid requirements after surgery. Results: PPI decreased significantly from the first to the second measurement (4.17 ± 2.7 vs. 1.6 ± 1.2, p < 0.001 for target; 4.46 ± 2.7 vs. 2.17 ± 2.1, p < 0.001 for control). Control and target measurements did not show significant differences. A linear regression analysis showed that early postoperative pain scores could be predicted with intraoperative piritramide with improved prediction after adding PPI scores, PCA opioids and surgery type. Forty-eight-hour pain scores at rest and in movement were correlated with intraoperative piritramide and control PPI after the PNB in movement and with second-postoperative-day opioids and target PPI scores before block insertion, respectively. Conclusions: While the effect of an FIB and ACB could not be shown with PPI postoperative pain scores due to a large effect of opioids, perioperative PPI was shown to be associated with postoperative pain. These results suggest that preoperative PPI may be used to predict postoperative pain.

The applications of cryoneurolysis for acute and chronic pain management

BACKGROUND

Cryoneurolysis is a term used to describe the application of extreme cold to targeted nerve tissue. The primary goal of the application of a thermal neurolytic technique is to disrupt the conduction of pain signals from the periphery to the central nervous system and eliminate or diminish the experience of pain. Recent advancements in ultrasound technology coupled with the development and approval of handheld devices specifically designed to deliver cryoneurolysis has expanded the use of this modality in the perioperative setting.

APPLICATION

Surgical procedures including total knee arthroplasties, shoulder arthroplasties, thoracotomies, and mastectomies have all demonstrated long-term pain relief benefits when cryoneurolysis has been administered days to weeks prior to the planned procedure. In addition, the newly designed handheld device allows for office-based clinical use and has been utilized for various chronic pain conditions including neuropathic and phantom limb pain.

CONCLUSION

The evidence clearly demonstrates that cryoneurolysis has a low risk profile and when administered appropriately, provides prolonged analgesia without promoting motor blockade. This narrative review article describes the unique mechanism of action of cryoneurolysis for prolonged pain relief and provides emerging evidence to support its applications in both acute and chronic pain management.

Cost comparison between spinal versus general anesthesia for hip and knee arthroplasty: an incremental cost study

PURPOSE

Wait list times for total joint arthroplasties have been growing, particularly in the aftermath of the COVID-19 pandemic. Increasing operating room (OR) efficiency by reducing OR time and associated costs while maintaining quality allows the greatest number of patients to receive care.

METHODS

We used propensity score matching to compare parallel processing with spinal anesthesia in a block room vs general anesthesia in a retrospective cohort of adult patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). We compared perioperative costs, hospital costs, OR time intervals, and complications between the groups with nonparametric tests using an intention-to-treat approach.

RESULTS

After matching, we included 636 patients (315 TKA; 321 THA). Median [interquartile range (IQR)] perioperative costs were CAD 7,417 [6,521-8,109], and hospital costs were CAD 10,293 [9,344-11,304]. Perioperative costs were not significantly different between groups (pseudo-median difference [MD], CAD -47 (95% confidence interval [CI], -214 to -130; P = 0.60); nor were total hospital costs (MD, CAD -78; 95% CI, -340 to 178; P = 0.57). Anesthesia-controlled time and total intraoperative time were significantly shorter for spinal anesthesia (MD, 14.6 min; 95% CI, 13.4 to 15.9; P < 0.001; MD, 15.9; 95% CI, 11.0 to 20.9; P < 0.001, respectively). There were no significant differences in complications.

CONCLUSION

Spinal anesthesia in the context of a dedicated block room reduced both anesthesia-controlled time and total OR time. This did not translate into a reduction in incremental cost in the spinal anesthesia group.

Extending Perioperative Analgesia with Ultrasound-Guided, Percutaneous Cryoneurolysis, and Peripheral Nerve Stimulation (Neuromodulation)

The use of regional anesthesia is key to a successful approach to improving postoperative analgesia, which involves local anesthetic deposition either around peripheral nerves or within a fascial plane. Unfortunately, the realistic duration even with continuous peripheral nerve blocks usually does not match the duration of surgical pain, comprising a major limitation. Here, the use of 2 interventional modalities-ultrasound-guided percutaneous cryoneurolysis and peripheral nerve stimulation-is discussed, both of which may be used to treat acute and subacute pain and may therefore have a positive impact on the incidence and severity of chronic pain development.

Preparation and evaluation of liposome with ropivacaine ion-pairing in local pain management

Local analgesia is one of the most desirable methods for postoperative pain control, while the existing local anesthetics have a short duration of analgesic effect. Nano-drug carriers have been widely used in various fields and provide an excellent strategy for traditional drugs. Although the existing liposomes for local anesthetics have certain advantages, their instability and complexity of the preparation process still cannot be ignored. Here, we developed novel ropivacaine hydrochloride liposomes with improved stability and sustained release performance by combining ropivacaine hydrochloride with sodium oleate in liposomes via hydrophobic ion-pairing (HIP). The liposomes are easy to prepare, inexpensive, and suitable for mass production. The infrared (IR), particle size, and Zeta potential measurements adequately characterized the complex, which showed a diameter of 81.09 nm and a zeta potential of -83.3 mV. Animal behavioral experiments, including the hot plate test and von Frey fiber test, demonstrated that the liposome system had a prolonged analgesic effect of 2 h versus conventional liposome preparations, consistent with the results of in vitro release experiments. In addition, in vitro cytotoxicity evaluations in RAW264.7 cells and in vivo evaluations revealed the biocompatibility and safety of the ropivacaine-sodium oleate ion-paired liposome (Rop-Ole-Lipo) system as a suitable local anesthetic for local pain management. Our findings provide a new idea for the preparation of local anesthetics.

Patient Safety During Anesthesia: 100 Years of Progress Documented in Anesthesia & Analgesia

Anesthesiology has evolved to be a leader in addressing patient safety. Our specialty has overcome serious morbidities including explosions, fires, organ toxicity, fatal arrhythmias, and hypoxic brain damage. Anesthesia safety has been significantly improved due to modern drug development, technical advances, and a strong leadership willing to apply human factors and systems' research strategies, but patient safety concerns remain at the forefront as we strive to improve patient care even further. This year marks the centennial year since the publication of the first issue of Anesthesia & Analgesia. Today, the International Anesthesia Research Society (IARS) and Anesthesia & Analgesia continue to advance the boundaries of patient safety by disseminating practice standards, serving as a forum for novel ideas, and supporting research advancements. This review will discuss several topics published in Anesthesia & Analgesia that exemplify steady changes leading to the safe practices that we rely on currently as well as other IARS activities that have advocated and elevated patient safety within the specialty.

Controlled activation of cortical astrocytes modulates neuropathic pain-like behaviour

Chronic pain is a major public health problem that currently lacks effective treatment options. Here, a method that can modulate chronic pain-like behaviour induced by nerve injury in mice is described. By combining a transient nerve block to inhibit noxious afferent input from injured peripheral nerves, with concurrent activation of astrocytes in the somatosensory cortex (S1) by either low intensity transcranial direct current stimulation (tDCS) or via the chemogenetic DREADD system, we could reverse allodynia-like behaviour previously established by partial sciatic nerve ligation (PSL). Such activation of astrocytes initiated spine plasticity to reduce those synapses formed shortly after PSL. This reversal from allodynia-like behaviour persisted well beyond the active treatment period. Thus, our study demonstrates a robust and potentially translational approach for modulating pain, that capitalizes on the interplay between noxious afferents, sensitized central neuronal circuits, and astrocyte-activation induced synaptic plasticity.

Astrocytes may contribute to synaptic remodelling in the cortex in chronic pain states. Here the authors describe modulation of astrocyte activity to drive circuit reorganization in somatosensory cortex in mice, along with peripheral nerve block, which could be a potential therapeutic approach for the treatment of chronic pain.