Single-shot Peripheral Nerve Block Research Articles

Does Liposomal Bupivacaine Injectable Suspension Peripheral Nerve Block Further Aid in Decreasing At-home Narcotic Utilization in Children and Adolescents After Anterior Cruciate Ligament Reconstruction

Background: Opioid misuse and addiction among children and adolescents is an increasingly concerning problem. This study sought to determine whether liposomal bupivacaine injectable suspension admixture administered as a single-shot adductor canal peripheral nerve block (SPNB+BL) would decrease utilization of at-home opioid analgesics after anterior cruciate ligament reconstruction (ACLR) in adolescents compared with single-shot peripheral nerve block with bupivacaine (SPNB+B) alone. Methods: Consecutive ACLR patients with or without meniscal surgery by a single surgeon were enrolled. All received a preoperative single-shot adductor canal peripheral nerve block with either admixture of liposomal bupivacaine injectable suspension with 0.25% bupivacaine (SPNB+BL) or 0.25% bupivacaine alone (SPNB+B). Postoperative pain management included cryotherapy, oral acetaminophen, and ibuprofen. A prescription for 10 doses of hydrocodone/acetaminophen (5/325 mg) was provided in a sealed envelope with instructions to only use in the case of uncontrolled pain. Pain using the visual analog scale; number of consumed narcotics, acetaminophen, ibuprofen, and pain treatment satisfaction for the first 3 postoperative days were recorded. Statistical analysis was performed. Results: Fifty-eight patients were enrolled, the average age was 15±1.5 years (SPNB+B=32 patients, SPNB+BL=26 patients). Forty-seven patients (81%) did not require home opioids postoperatively. A significantly lower proportion of patients in the SPNB+BL group required opioids compared with control patients (7.7% vs. 28.1%, P=0.048). Average opioid use was 2 morphine milligram equivalents (MME), 0.4 pills (range, 0 to 20 MME). There were no differences in the visual analog scale or pain treatment satisfaction scores, other demographics, or other operative data. Inverse probability of treatment weighting analysis that was performed to account for any potential group differences revealed home opioid use between groups is significantly different (P<0.001). Conclusions: Liposomal bupivacaine injectable suspension admixture administered as an adductor canal nerve block in adolescents undergoing ACLR effectively reduces home opioid usage postoperatively compared with bupivacaine alone. Level of Evidence: Level II—prospective comparative study.

Analgesic Efficacy of Multiple Single-Shot Peripheral Nerve Blocks on Postoperative Short-Term Opioid Usage and Clinical Outcomes in a Suburban Hospital Setting.

BackgroundPreoperative single-shot peripheral nerve blocks (sPNBs) represent promising candidates for controlling postoperative pain, reducing dependence on opioid medications, and reducing postoperative constipation and ileus. However, there is not yet complete consensus regarding their efficacy. The primary aim of this study was to assess the impact of various sPNBs on patient short-term opioid demands and pain management parameters.MethodsThis single-center study retrospectively reviewed a cohort of 94 adult, elective surgery inpatients (ASA physical status I-III) scheduled for different operations. Sixty-four (68.1%) were selected for sPNB administration (group 1) and compared to the untreated group (group 0) for different clinical parameters.ResultsContrary to the starting hypothesis, a higher proportion of group 1 patients experienced increasing pain intensities during the immediate postoperative period (P < 0.05, Fisher’s exact test), while requiring more bowel care medications (P < 0.05, χ2 test). Multiple linear regression modeling, however, showed that recovery time positively correlated with the opioid amount consumed (P < 0.01). Although limited, the results obtained in this study do not support an analgesic efficacy for sPNBs.ConclusionIn conclusion, even though our data must be viewed within the limitations of our retrospective study and small group size, we did not find any compelling evidence for the efficacy of sPNB administration in the perioperative period.

Locoregional anesthesia for post-operative pain management in microsurgical reconstruction of the lower extremities: A retrospective study

ObjectiveOpioid-based analgesia is often used in the management of postoperative pain in arthroplasty cases. This article analyses the safety of single-shot peripheral nerve block (PNB) and potential analgesic benefits in patients undergoing lower limb free flap reconstruction. MethodsA retrospective review including all patients undergoing lower limb reconstruction with free flaps between October 2017 and April 2020 was performed. Patients were divided into two groups based on PNB utilization. The use of oral opioids, post-operative pain scores, flap-related outcomes, patient morbidity, and length of hospital stay (LOS) were compared between groups. ResultsThirty-one patients who underwent lower limb reconstruction with free flaps, were finally included in the study. Preoperative PNB was performed on 14 patients, while 17 patients received general anesthesia (GA) alone. Pain at rest, measured using the visual analog scale (VAS) score, was significantly lower (2.2 ± 1.7 vs. 4.9 ± 1.7) in the PNB group on postoperative day 1 (POD). The mean [median]±SD amounts of opioids consumed in morphine milligram equivalent (MME) were significantly lower in the PNB group on both POD1 (33.5 [22.5] ± 33.9 vs. 61.6 [48.0] ± 39.0), POD2 (29.0 [15.0] ± 29.2 vs. 58.0 [52.5] ± 37.0) and cumulatively over 7 days (164.0 [197.0] ± 132.8 vs. 315.4 [225] ± 203.2). Complication rates and LOS were not statistically different between groups, although trending toward lower take-back procedures and major complications in the PNB group. ConclusionPreoperative single-shot PNB significantly reduced postoperative opioid use and patient-reported pain severity and was not associated with an increase in complication rates.

Do Continuous Peripheral Nerve Blocks Decrease Home Opioid Use Following Anterior Cruciate Ligament Reconstruction in Children and Adolescents? The Envelope Please.

Levels of opioid misuse and addiction among children and adolescents have reached alarming proportions. Exposure to opioids after surgery for anterior cruciate ligament reconstruction (ACLR), which is commonly performed in young athletes, increases this risk. This study was designed to evaluate whether continuous peripheral nerve block (CPNB) with placement of an elastomeric reservoir ball, compared with single-shot peripheral nerve block (SPNB), would decrease the need for home opioid analgesia and improve pain control after ACLR in children and adolescents. Prospectively collected data from a consecutive cohort that underwent ACLR by a single surgeon were retrospectively reviewed. Patients who received ACLR with 72-hour CPNB were assigned to Group 1. Patients who received ACLR with SPNB were assigned to Group 2. Postoperative pain management included cryotherapy, oral acetaminophen, and ibuprofen. A prescription for 10 doses of hydrocodone/acetaminophen (5/325 mg) was provided in a sealed envelope with instructions that the prescription should only be used in the case of uncontrolled pain. Reports of no opioid use were corroborated by the unopened envelope and unfilled prescription. One hundred and ninety-six patients were enrolled in the study (SPNB=114 patients, CPNB=82 patients). Average age was 15±1.5 years (115 female). A total of 138 patients (70%) did not need home opioid analgesia after surgery. Of the 58 patients (30%) that did there were 35 (30.7%) in the SPNB group and 23 (28.0%) in the CPNB group (P=0.659). There were no differences between groups in demographics, operative data, or visual analog scale scores on any postoperative day. The findings of this study demonstrate equivalent pain control and opioid consumption in children and adolescents undergoing ACLR treated with either a CPNB or a SPNB. At-home opioid analgesia use can be negated after ACLR in 70% of children and adolescents. For the patients in this study who required opioids, average use was only 2 pills of 5 mg hydrocodone/325 mg acetaminophen, with no child using more than 10 pills. Level II-therapeutic.

Adjuvant Drugs for Peripheral Nerve Blocks: The Role of Alpha-2 Agonists, Dexamethasone, Midazolam, and Non-steroidal Anti-inflammatory Drugs.

Adjuvant drugs for peripheral nerve blocks are a promising solution to acute postoperative pain and the transition to chronic pain treatment. Peripheral nerve blocks (PNB) are used in the brachial plexus, lumbar plexus, femoral nerve, sciatic nerve, and many other anatomic locations for site-specific pain relief. However, the duration of action of a PNB is limited without an adjuvant drug. The use of non-opioid adjuvant drugs for single-shot peripheral nerve blocks (sPNB), such as alpha-2 agonists, dexamethasone, midazolam, and non-steroidal anti-inflammatory drugs, can extend the duration of local anesthetics and reduce the dose-dependent adverse effects of local anesthetics. Tramadol is a weak opioid that acts as a central analgesic. It can block voltage-dependent sodium and potassium channels, cause serotonin release, and inhibit norepinephrine reuptake and can also be used as an adjuvant in PNBs. However, tramadol’s effectiveness and safety as an adjuvant to local anesthetic for PNB are inconsistent. The effects of the adjuvants on neurotoxicity must be further evaluated with further studies to delineate the safety in their use in PNB. Further research needs to be done. However, the use of adjuvants in PNB can be a way to help control postoperative pain.

DOES A CONTINUOUS PERIPHERAL NERVE BLOCK REDUCE HOME OPIOID USE IN CHILDREN AND ADOLESCENTS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION? THE ENVELOPE PLEASE.

Background:Anterior cruciate ligament reconstruction (ACLR) is commonly performed in youth athletes. Opioid misuse and addiction have reached alarming proportions.Purpose:To evaluate whether a continuous peripheral nerve block (CPNB) with placement of an elastomeric reservoir ball would decrease the need for home opioid analgesia when compared to a single-shot peripheral nerve block (SPNB) following ACLR in children and adolescents.Methods:A continuous cohort was analyzed via retrospective review of prospectively collected data following ACLR by a single surgeon. Group 1 had ACLR at our in-patient hospital and received a 72-hour CPNB. Group 2 had ACLR at our outpatient surgery centers and received a SPNB.Post-operative pain management included cryotherapy, oral acetaminophen and ibuprofen. A prescription for 10 doses of hydrocodone/acetaminophen (5/325mg) was provided in a sealed envelope with instructions to only be used for uncontrolled pain. On a three-day written log all children recorded their post-op Visual Analog Scale (VAS), amount of ibuprofen, acetaminophen and hydrocodone taken. Those reporting no narcotics needed to provide the unopened envelope and unfilled prescription. Hydrocodone utilization was converted to morphine milligram equivalents (MME). 1 mg hydrocodone = 1 MME. A state Controlled Substance Utilization Review and Evaluation System (CURES) inquiry was made on all participants in the peri-operative period.Demographic and operative data were collected. This study was powered to detect a difference of 20% in rate of narcotic consumption, should one exist, at beta=0.80, alpha<0.05. All analyses were performed using SPSS v. 26 with alpha set at p<0.05 to declare significance.Results:One hundred ninety-six patients were included in the study with an average age of 15 years (range 10-19y). 58 (30%) took hydrocodone/acetaminophen post ACLR, 39 female (67.2%) 19 male (32.8%). The CPNB group consumed 4.7 MME 95 % Confidence Interval (CI) 2.5-6.9 vs 6.5 MME 95 % CI 4.3-8.7 in the SPNB group (p=0.427) There were no significant differences in demographics, operative data or VAS scores. (Table).Conclusion:Home narcotic use can be negated in 70% of children and adolescents following ACLR regardless of duration of peripheral nerve block. In those requiring narcotics, the average utilization was only 1.3 pills of hydrocodone/acetaminophen with no child using more than 10 pills. The MME can be diminished with a CPNB however not significant enough to recommend routine use. We postulate the sealed envelope was as a barrier and psychological deterrent to filling the opioid prescription.

Enhanced Post-Operative Recovery with Continuous Peripheral Nerve Block After Lower Extremity Amputation

Despite progress in perioperative care standards, there has not been a significant risk reduction in morbidity and mortality rates of lower extremity amputations, an intermediate risk surgery performed on high risk patients. The single-shot peripheral nerve block has shown equivocal impact on postoperative course following lower extremity amputation. Hence, we assessed the potential of preemptive use of continuous catheter-based peripheral nerve block in lower extremity amputations for reduction in pulmonary complications, acute post-operative pain scores, and opioid use in post-operative period. A retrospective review of a quality improvement project initiated in 2018 was conducted to compare outcomes amongst general anesthesia in combination with a catheter-based peripheral nerve block (catheter group) and general anesthesia alone in patients receiving lower extremity amputation. The rate of postoperative pulmonary complications was identified as a primary endpoint. The secondary outcomes assessed were acute post-operative pain scores and opioid consumption up to 48 hours. Our analysis was adjusted for potential confounding variables inclusive of demographics, medical comorbidities, type of surgical procedure and smoking status. Ninety-six patients were included in the study (61 in the general anesthesia group, 35 in the catheter group). After adjusting for baseline demographics, comorbidities, surgical technique and smoking status, the odds of postoperative pulmonary complications were significantly lower with catheter-based peripheral nerve block in comparison to general anesthesia alone, OR 0.11 [95% CI, 0.01- 0.88] (P = 0.048). The decrease in acute pain scores was also observed in the catheter group when compared to general anesthesia alone, OR 0.72 [95% CI, 0.56 - 0.93] (P = 0.012). Similarly, the opioid consumption was also lower in the catheter group in comparison to general anesthesia alone, OR 0.97 [95% CI, 0.95 - 0.99] (P = 0.025). Preemptive use of continuous peripheral nerve block in patients undergoing lower extremity amputation reduces the incidence of pulmonary complications, acute postoperative pain scores and narcotic use in post-operative period.

The effect of perineural dexamethasone on rebound pain after ropivacaine single-injection nerve block: a randomized controlled trial

BackgroundRebound pain after a single-shot nerve block challenges the real benefit of this technique. We aimed to investigate whether perineural dexamethasone addition decreased the incidence of rebound pain after a single-shot nerve block.MethodsWe randomly allocated 132 patients scheduled for open reduction internal fixation of an upper extremity closed fracture under single-shot peripheral nerve block and sedation into two groups. Patients in the dexamethasone group received nerve block with 0.375% ropivacaine and 8 mg dexamethasone, while those in the control group received ropivacaine only. Sixty-three patients in the dexamethasone group and 60 patients in the control group were analyzed for the incidence of rebound pain 48 h after block administration, which was the primary outcome. The secondary outcomes included the highest self-reported numeric rating scale (NRS) pain score, and NRS at 8, 12, 24, and 48 h after the block, sufentanil consumption, sleep quality on the night of surgery, patient satisfaction with the pain therapy, blood glucose at 6 h after the block, pain and paresthesia at 30 days after surgery.ResultsThe incidence of rebound pain was significantly lower in the dexamethasone group (7 [11.1%] of 63 patients) than in the control group (28 [48.8%] of 60 patients [RR = 0.238, 95% CI (0.113–0.504), p = 0.001]. Dexamethasone decreased opioid consumption in 24 h after surgery (p < 0.001) and improved the sleep quality score on the night of surgery (p = 0.01) and satisfaction with pain therapy (p = 0.001). Multivariate logistic regression analysis showed that only group allocation was associated with the occurrence of rebound pain [OR = 0.062, 95% CI (0.015–0.256)]. Patients in the dexamethasone group reported later onset pain (19.7 ± 6.6 h vs 14.7 ± 4.8 h since block administration, mean ± SD, p < 0.001) and lower peak NRS scores [5 (3, 6) vs 8 (5, 9), median (IQR), p < 0.001] than those in the control group.ConclusionsThe perineural administration of 8 mg dexamethasone reduces rebound pain after a single-shot nerve block in patients receiving ORIF for an upper limb fracture.Trial registrationThis study was retrospectively registered in the Chinese Clinical Trial Registry (ChiCTR-IPR-17011365) on May 11th, 2017.

The use of the Panda-Nerve Block pain app in single-shot peripheral nerve block patients: a feasibility study.

Peripheral nerve blocks (PNBs) provide excellent perioperative analgesia but can increase the risk of severe postoperative pain once the block wears off. Poor adherence to discharge instructions may increase this risk. Panda-Nerve Block(Panda) is an app that alerts the patient to assess their PNB, score their pain, and take scheduled pain medication. We assessed the usability and feasibility of Panda for assisting patients after receiving a PNB. Twenty-nine patients tested Panda in three rounds, for two to seven days, postoperatively to assess and manage their pain and PNB. Feedback was provided via phone interview and the Computer System Usability Questionnaire (CSUQ). Additionally, each user's usage log was analyzed for parameters such as alert response times. Feasibility was determined by alert responses that occurred before the next alert, with a goal of greater than 50%. User adherence was measured as percentage compliance with alerts within one hour; usability and user satisfaction were determined from the CSUQ and interviews. A median [interquartile range (IQR)] of 68 [34-93]% responded before the next alert during the first 48 hr of app use, and 83 [54-92]% responded before the next alert with 87 [75-96]% of these within one hour. There were no significant differences in usage between rounds. Ninety-three percent of patients reported Panda to be easy to use and helpful, and 79% of patients would use Panda again. Critical themes included changes to the layout and appearance, clarification of the language of the PNB check, and requests for dynamic adjustments to the medication schedule based on user responses. Panda-Nerve Block is a feasible method for PNB patients to manage postoperative pain with a high response rate. Future work should include providing two-way communication for patients and clinicians and assessing its effect on pain outcomes. www.clinicaltrials.gov (NCT03369392); registered 5 December 2017.

Catheter use in regional anesthesia: pros and cons.

Continuous peripheral nerve blocks refer to a local anesthetic solution administered via perineurally placed catheters in an effort to extend the benefits of a single-shot peripheral nerve block. They offer several advantages in the postoperative period including excellent analgesia, reduced opioid consumption and associated side effects, enhanced rehabilitation and improved patient satisfaction. The current trend towards less invasive, one-day surgery and enhanced recovery programs may decrease the requirement of catheter use. Prolonged motor block in particular is associated with undesirable outcomes. Should we routinely use continuous peripheral nerve blocks in our daily practice? This PRO-CON debate aims at answering the question from the experts' perspectives. Fascial compartment and wound catheters are outside the scope of this debate.

An Assessment of Long-Term Opioid Use Following Tibial Plateau Fracture Repair

Objectives: Is there a difference in percentage of opioid use at 3 and 6 months among different races/ethnicities following tibial plateau fracture repair after controlling for potential confounders? Methods: Retrospective secondary data analysis of 18- to 65-year-old patients with operative tibial plateau fractures between 2006 and 2015 at a level-I trauma center. Exclusion criteria included preinjury opioid use or history of opioid dependence, American Society of Anesthesiologists class ≥3, renal or lower extremity neurological impairment, and/or rheumatoid arthritis. Three hundred fifteen operative tibial plateau fractures were identified and, following application of our exclusion criteria, final sample size was 211. Intervention included single-shot peripheral nerve block (PNB) vs. no PNB. Main outcome measurements were opioid use at 3 or 6 months compared among all race/ethnicities. Results: Black patients were less likely to be on prescription opioids than whites at both 3 months (p = 0.015, odds ratio [OR] = 0.396 [0.188 to 0.835]) and 6 months (p = 0.027, OR = 0.239 [0.067 to 0.852]). Hispanic patients did not differ statistically from white patients in having an opioid prescription at 3 or 6 months. Smokers were independently more likely to be on prescription opioids than nonsmokers at 6 months (p = 0.013, OR = 2.874 [1.245 to 6.635]). Conclusions: Disparities exist with regard to opioid use among white and black patients following lower extremity surgery, regardless of PNB status. White patients are at risk for long-term opioid use following tibial plateau fracture repair and black patients may not be receiving adequate pain control postoperatively. Smoking was found to be associated with long-term opioid use.

Comparison of Continuous Adductor Canal Catheters and Single-shot Peripheral Nerve Blocks Providing Analgesia After Unicondylar Knee Replacement, as Part of an Enhanced Recovery After Surgery Program

With the current trend toward ambulatory joint replacements, it is important to identify the approach to postoperative analgesia which best balances comfort and mobility. Adductor canal blocks provide analgesia after unicondylar knee replacement and can be performed with either an infusion catheter [adductor canal block catheter (ACB-C)] or as a single-shot injection [adductor canal block single-shot injection (ACB-SS)]. We conducted a retrospective analysis comparing the perceived quality of analgesia achieved by the 2 techniques, hypothesizing that patients receiving ACB-Cs would have less opioid consumption and lower pain scores than those who received ACB-SSs. After Institutional Review Board approval, we identified patients who underwent unicondylar knee arthroplasty between August and December 2015. Patients designated American Society of Anesthesiologists physical status 1 to 3 were included. Those discharged home on postoperative day (POD) 0 or provided an alternative nerve block were excluded. The primary outcome was opioid consumption over POD 1. Morning and afternoon pain scores were also evaluated. Of the 125 patients identified, there were 17 exclusions. Of those remaining, 69 received an ACB-C and 38 received an ACB-SS. The median amount of opioid use was lower in the ACB-C group than in the ACB-SS group [12 mg (8, 16) vs. 26 mg (20, 31.5), P&lt;0.0001]. Patients treated with ACB-Cs had lower pain scores in the morning [0 (0, 1) vs. 3.5 (0, 5), P&lt;0.0001] and afternoon [0 (0, 0) vs. 4 (0, 5), P&lt;0.0001] on POD 1. Our data suggest an association between adductor canal catheters and both lower opioid consumption and pain scores. A prospective randomized trial is required to confirm this finding and help determine the optimal intervention.

Liposomal bupivacaine versus indwelling interscalene nerve block for postoperative pain control in shoulder arthroplasty: a prospective randomized controlled trial

Pain management strategies following shoulder arthroplasty vary significantly. Liposomal bupivacaine (LB) is an extended-release delivery of a phospholipid bilayer encapsulating bupivacaine that can result in drug delivery up to 72 hours. Prior studies in lower extremity surgery demonstrated efficacy of LB in comparison to a single-shot peripheral nerve block; however, no study has investigated LB in a total shoulder arthroplasty population. Therefore, this study compared LB vs. an indwelling interscalene nerve block (IINB). This is a prospective, randomized study of 83 consecutive shoulder arthroplasty patients; 36 patients received LB and a "bridge" of 30 mL of 0.5% bupivacaine, and 47 patients received an IINB. Postoperative visual analog scale pain levels, opiate consumption measured with oral morphine equivalents, length of hospital stay, and postoperative complications were recorded. Continuous variables were compared using an analysis of variance with significance set at P < .05. Visual analog scale pain scores were statistically higher in the LB cohort immediately postoperatively in the postanesthesia care unit (7.25 vs. 1.91; P = .000) as well as for the remainder of postoperative day 0 (4.99 vs. 3.20; P = .005) but not for the remainder of admission. Opiate consumption was significantly higher among the LB cohort in the postanesthesia care unit (31.79 vs. 7.47; P = .000), on postoperative day 0 (32.64 vs. 15.04; P = .000), and for the total hospital admission (189.50 vs. 91.70, P = .000). Complication numbers and length of stay were not statistically different. Use of an IINB provides superior pain management in the immediate postoperative setting as demonstrated by decreased narcotic medication consumption and lower subjective pain scores.

Combination of general anesthesia and peripheral nerve block with low-dose ropivacaine reduces postoperative pain for several days after outpatient arthroscopy: A randomized controlled clinical trial.

Background:Effective methods for postoperative pain relief are an important concern in outpatient surgery. For arthroscopies we combine a single-shot peripheral nerve block using low-volume, low-concentration ropivacaine with general anesthesia. We hypothesized that the patients would have less postoperative pain and be more rapidly home ready than after general anesthesia alone.Methods:Patients (American Society of Anesthesiologists I–III, 18–80 years old) scheduled for outpatient arthroscopy on the upper or lower extremity were randomized to have either a combination of peripheral nerve block and general anesthesia (NB + GA, study group) or general anesthesia alone (GA, control group). The relevant nerve was localized by ultrasound and 10 mL ropivacaine 0.2% was injected. General anesthesia was with propofol and remifentanil. Numeric rating scales were used to assess pain and patient satisfaction in the recovery room, on the evening of surgery, and on the following 2 days.Results:A total of 120 patients participated in the study (NB + GA: 61; GA: 59). The percentage of patients reporting relevant pain in the recovery room were 0% versus 44% (P < 0.001), on the evening after surgery 3% versus 80% (P < 0.001), and on days 1 and 2 postsurgery 12% versus 73% and 12% versus 64% (NB + GA vs GA, respectively). Median time to home discharge was NB + GA 34.5 min (range 15–90) versus GA 55 min (20–115) (P < 0.001).Conclusions:The combination of a peripheral nerve block with low-dose ropivacaine and general anesthesia reduced postoperative pain compared with general anesthesia alone for several days after outpatient arthroscopy. It also shortened the time to home discharge.

Case Scenario: Compartment Syndrome of the Forearm in Patient with an Infraclavicular Catheter

Case Scenario: Compartment Syndrome of the Forearm in Patient with an Infraclavicular Catheter

Effect of a Preemptive Femoral Nerve Block on Cytokine Release and Hyperalgesia in Experimentally Inflamed Skin of Human Volunteers

Tissue injury is associated with the local release of inflammatory and nociceptive mediators and the development of hyperalgesia. It is unclear whether interrupting neuronal signaling using regional anesthetic techniques at the time of the injury modifies local nociceptive and inflammatory processes. The aim of this study was to determine whether a peripheral nerve block at the time of tissue injury could modify the development of wound hyperalgesia and the local release of inflammatory and nociceptive mediators. Twelve healthy volunteers participated in this controlled, crossover, randomized study. A femoral nerve block or a sham block was established before inducing an experimental UVB burn on the thigh. Twenty-four hours later, the interstitial wound fluid was sampled, and mechanical and heat pain thresholds were assessed. Wound fluid concentrations of an array of cytokines, chemokines, nerve growth factor, prostaglandin E2, and substance P were determined. Skin inflammation was associated with the release of inflammatory and nociceptive mediators and resulted in significant tissue hyperalgesia (P < 0.001). However, the presence of a fully established peripheral nerve block at the time of tissue injury did not alter the development of hyperalgesia after regression of the block. Similarly, the presence of a peripheral nerve block did not modify the release of inflammatory or nociceptive mediators. These findings suggest that a preemptive, single-shot peripheral nerve block minimally affects wound hyperalgesia and inflammation. Continuous nerve block techniques may be better suited to alter nociceptive and inflammatory events in wounds beyond the duration of the block.

Peripheral nerve catheter techniques

The placement of a catheter in the sheath of a nerve plexus or close to a peripheral nerve allows the anaesthetist to provide continuous regional anaesthesia and analgesia. The main benefit to the patient is excellent analgesia that can be prolonged for days. The anaesthetist needs experience and expertise in single-shot peripheral nerve blocks, specialized equipment and the courage to fail.

Regional Anesthesia; Volume 18, Number 2 of Anesthesiology Clinics of North America

Regional Anesthesia; Volume 18, Number 2 of Anesthesiology Clinics of North America