Search

Chronic pain after surgery, also known as chronic postsurgical pain (CPSP), is recognized as a significant public health issue with serious medical and economic consequences. Current research on CPSP underscores the significant roles of both peripheral and central sensitization in pain development and maintenance. Peripheral sensitization occurs at the site of injury, through the hyperexcitability of nerve fibers due to surgical damage and the release of inflammatory mediators. This leads to increased expression of pronociceptive ion channels and receptors, such as transient receptor potential and acid-sensing ion channels (ASIC), enhancing pain signal transmission. Central sensitization involves long-term changes in the central nervous system, particularly in the spinal cord. In this context, sensitized spinal neurons become more responsive to pain signals, driven by continuous nociceptive input from the periphery, which results in an enhanced pain response characterized by hyperalgesia and/or allodynia. Key players in this process include N-methyl-D-aspartate receptor and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, along with proinflammatory cytokines and chemokines released by activated glia. These glial cells release substances that further increase neuronal excitability, maintaining the sensitized state and contributing to persistent pain. The activation of antinociceptive systems is required for the resolution of pain after surgery, and default in these systems may also be considered as an important component of CPSP. In this review, we will examine the clinical factors underlying CPSP in patients and the mechanisms previously established in preclinical models of CPSP that may explain how acute postoperative pain may transform into chronic pain in patients., Competing Interests: Competing interests: PR received honoraria as a consultant and to give educational lectures not related to the present review, from the following companies: Medasense, Abbvie, Medtronic-Covidien, BioSyent, and Merck. AT and CR declare no conflict of interests related to the current investigation., (© American Society of Regional Anesthesia & Pain Medicine 2025. No commercial re-use. See rights and permissions. Published by BMJ Group.)

The American Society of Regional Anesthesia and Pain Medicine (ASRA) 2012 survey of meeting attendees showed that existing ASRA anticoagulation guidelines for regional anesthesia were insufficient for their needs. Those surveyed agreed that procedure-specific and patient-specific factors required separate guidelines for pain and spine procedures. In response, a guidelines committee was formed. After preliminary review of published complications reports and studies, the committee stratified interventional spine and pain procedures according to potential bleeding risk: low-, intermediate-, and high-risk procedures. The ASRA regional anesthesia anticoagulation guidelines were largely deemed appropriate for the low- and intermediate-risk categories, but the high-risk category required further investigation. The first guidelines specific to interventional spine and pain procedures were published in 2015. Recent reviews evaluating bleeding complications in patients undergoing specific interventional pain procedures, the development of new regional anesthesia and acute pain guidelines, and the development of new anticoagulants and antiplatelet medications necessitate complementary updated guidelines. The authors desired coordination with the authors of the recently updated regional and acute pain anticoagulation guidelines. The latest evidence was sought through extensive database search strategies and the recommendations were evidence based when available and pharmacology driven otherwise. We could not provide strength and grading of these recommendations because there are not enough well-designed large studies concerning interventional pain procedures to support such grading. Although the guidelines could not always be based on randomized studies or on large numbers of patients from pooled databases, it is hoped that they will provide sound recommendations and the evidentiary basis for such recommendations. This publication is intended as a living document to be updated periodically with consideration of new evidence.

Background and Objectives: We aimed to investigate the effect of therapeutic ultrasound (TU) on pain sensitivity and the concentration inflammatory cytokines in a thoracotomy rat model., Methods: Rats were distributed randomly into 4 groups: (1) sham operated, (2) thoracotomy and rib retraction (TRR), (3) TRR rats that received TU (TRR + TU-1), and (4) TRR rats that received TU with the ultrasound turned off (TRR + TU-0). Ultrasound was set at 1-MHz frequency (1.0-W/cm intensity and 100% duty cycle for 5 minutes), began on postoperative day (POD) 10, and then continued once per day, 5 days a week for 3 weeks., Results: The TRR and TRR + TU-0 rats encountered tactile hypersensitivity from PODs 10 to 28. Mechanical withdrawal thresholds were increased (all P < 0.05) following 5 days of TU, but thresholds remained significantly lower than baseline values. Therapeutic ultrasound increased the subcutaneous, but not body temperature. All groups receiving TRR demonstrated an increase in concentration of interleukin 1β and tumor necrosis factor α (TNF-α) on POD 14; however, the rise in TNF-α concentration was less in the TU-treated group than in the others. The decrease in concentration was greatest in the TRR + TU-1 group and similar between the TRR and TRR + TU-0 groups., Conclusions: Mechanical allodynia was partially resolved with TU. Tissue temperature increased with ultrasound, while TU restricted the up-regulation of interleukin 1β and TNF-α around the injured intercostal nerve.

Background and Objectives: Effective postoperative analgesia may enhance early rehabilitation after orthopedic surgery. This randomized double-blind trial investigates the relative contributions of adductor canal block and low-dose intrathecal morphine (ITM) to postoperative analgesia and functional recovery after total knee arthroplasty., Methods: Two-hundred one patients undergoing elective unilateral total knee arthroplasty under spinal anesthesia were randomized to 3 groups. All patients received standardized intraoperative local infiltration analgesia and postoperative oral analgesics. Patients in group 1 received a "sham" adductor canal block with 30 mL of normal saline. Patients in group 2 received an adductor canal block with 30 mL of ropivacaine 0.5% with 1:400,000 epinephrine, whereas patients in group 3 received the adductor canal block with the active drug and 100 μg of ITM. The primary outcome measure was the Timed Up and Go (TUG) test on the second postoperative day. Secondary outcomes included postoperative pain scores and opioid requirements, distance walked, time to hospital discharge, and self-reported functional outcomes at 3 months., Results: All 3 groups had similar values of TUG test on postoperative day (POD) 2 (46 [36-62], 45 [33-61], and 52 [41-69]; P = 0.166) as well as other short-term and 3-month functional outcomes. Patients in group 3 showed a favorable analgesic profile as evidenced by 3 positive secondary outcomes. These positive outcomes were lower pain scores 12 hours postoperatively both at rest (4 [2-6.3], 4 [2.3-6], and 3 [1-4]; P = 0.007) and on movement (6 [4-8], 6 [3-8], and 4 [2-6]; P = 0.002), a lower incidence of "rescue" intravenous patient-controlled analgesia (42%, 34%, and 20%; P = 0.031), and the lowest cumulative opioid requirements for the first 48 hours postoperatively (86 ± 71, 68 ± 46, and 59 ± 39; P < 0.005, group 3 compared with group 1)., Conclusions: Our data suggest that there is no difference in either the primary outcome of TUG test on POD 2, other immediate functional secondary outcomes, or in global functional outcome at 3 months postoperatively across all 3 groups. Our data also suggest an improved analgesic profile in the first 48 hours postoperatively when both adductor canal block and low-dose ITM (100 μg) are added to local infiltration analgesia as evidenced by several positive secondary outcomes of lower pain scores and opioid requirements., Clinical Trial Registration: This study was registered at ClinicalTrials.gov, identifier NCT02411149.

Background and Objectives: Management of postoperative pain after laparoscopic segmental colonic resections remains controversial. We compared 2 methods of analgesia within an Enhanced Recovery After Surgery (ERAS) program. The goal of the study was to investigate whether administration of intrathecal bupivacaine/morphine would lead to an enhanced recovery., Methods: A single-center, randomized, double-blind controlled trial was performed (NL43488.101.13). Patients scheduled for laparoscopic segmental intestinal resections were considered. Exclusion criteria were patients in whom contraindications to spinal anesthesia were present, conversion to open surgery, and gastric and rectal surgery. The intervention group received single-shot intrathecal bupivacaine/morphine (12.5 mg/300 μg), with an altered dose for older patients. The control group received a sham procedure and a bolus of piritramide (0.1 mg/kg). Both groups received standardized general anesthesia and a patient-controlled intravenous analgesia pump as postoperative analgesia. All patients were treated according to an ERAS protocol. A decrease in days to "fit for discharge" was the primary outcome., Results: Fifty-six patients were enrolled. Intervention group patients were fit for discharge earlier (median of 3 vs 4 days, P = 0.044). Furthermore, there was a significant decrease in opioid use and lower pain scores on the first postoperative day in the intervention group. There were no differences in adverse events (except for more pruritus), time to mobilization, fluid administration, or patient satisfaction., Conclusions: This randomized controlled trial shows that intrathecal morphine is a more effective method of postoperative analgesia in laparoscopic surgery than intravenous opioids within an ERAS program. Recovery is faster and less painful with intrathecal morphine. Other studies have confirmed these results, although data on faster recovery are new and require confirmation in future trials., Clinical Trial Registration: This study was registered at ClinicalTrials.gov, identifier NCT02284282.

Objective: Historically, regional anesthesia for surgery on the posterior thoracic wall has been limited to neuraxial and paravertebral nerve blocks. The erector spinae plane (ESP) block is a novel technique that anesthetizes the dorsal rami of the spinal nerves innervating the posterior thoracic wall. We report the use of the ESP block for this clinical application in a pediatric patient., Case Report: A healthy 3-year-old girl was scheduled for resection of a giant paraspinal lipoma extending over the T4-T7 dermatomes. She received a preoperative single-shot ESP block at the level of the T1 transverse process; this level was chosen to avoid the lipoma and cover the planned surgical incision over the T2-T8 dermatomes. Hemodynamic stability and excellent pain control perioperatively were obtained with minimal anesthetic requirements and no systemic analgesics apart from fentanyl administered for induction of anesthesia. Return to normal function (ambulation, feeding, and communication) was achieved within 2 hours after surgery. A pain score of 0 on the FLACC (Face, Legs, Activity, Cry, Consolability) scale was maintained until discharge from the hospital 4 hours after the surgery. First analgesic use was 18 hours after hospital discharge. No complications were reported., Conclusions: The ESP block is an effective option for surgery on the posterior thoracic wall. The opioid- and anesthetic-sparing effects exhibited in this case facilitated rapid postoperative recovery and early discharge.

Transversus abdominis plane (TAP) catheters are increasingly being used as an opioid-sparing analgesic technique following abdominal surgery. The aim of this systematic review is to evaluate the efficacy and safety of TAP catheters for postoperative analgesia following abdominal surgery in adults. The authors searched electronic databases and relevant reference lists for randomized controlled trials published between inception and January 2017. Twelve randomized controlled trials were identified, comprising 661 participants, with several trials showing either an equivalence or superiority in analgesia compared with the alternative modality. Because of the extremely heterogeneous nature of the studies, a specific consensus regarding their results, or the ability to construct a meta-analysis, is unviable. Although there are promising indications for the benefit of TAP catheter techniques, extrapolation/comparison of results and application to patient care will be better elucidated when there is more standardization of TAP catheter techniques and the methodology for measuring efficacy.

Background and Objectives: Adductor canal blocks (ACBs) are associated with improved analgesia, preserved quadriceps strength, and decreased length of hospitalization after total knee arthroplasty (TKA). However, controversy remains regarding the ideal location of a continuous block within the adductor canal, and it remains unclear whether similar clinical benefits are obtained irrespective of block location. In this randomized, double-blind, noninferiority study, we hypothesized that a continuous proximal ACB provides postoperative analgesia that is no worse than a continuous distal ACB., Methods: Subjects presenting for unilateral TKA were randomized in a 1:1 ratio to either a continuous proximal or distal ACB group. The primary outcome of this noninferiority study was opioid consumption within the first 24 hours following surgery. Secondary outcomes included quadriceps strength, pain scores, distance ambulated, and patient satisfaction., Results: Seventy-three subjects, 36 from the proximal group and 37 from the distal group, completed the study per protocol. The intention-to-treat analysis demonstrated a cumulative mean intravenous morphine equivalent consumption difference between the proximal and distal groups of -7.2 mg (95% confidence interval, -14.8 to 0.4; P < 0.001), demonstrating noninferiority of the proximal approach. The per-protocol analysis yielded similar results: -6.2 mg (95% confidence interval, -14.1 to 1.6; P < 0.001). No secondary outcomes showed statistically significant differences between the proximal and distal groups., Conclusions: This study demonstrates that a continuous proximal ACB offers noninferior postoperative analgesia compared with a distal continuous ACB in the first 24 hours after TKA., Clinical Trial Registration: ClinicalTrials.gov (NCT02701114).

In the gluteal and thigh region, the arteria comitans accompanies the sciatic nerve for a short distance, then penetrates the nerve and runs to the lower part of the thigh. There is no study that recognizes this artery as a guide to the location of the sciatic nerve. In this report, we describe a series of 6 knee arthroplasty patients in whom ultrasound-guided sciatic nerve block was successfully performed using color Doppler and pulsed wave Doppler to visualize the arteria comitans as a guide to the location of the sciatic nerve. We have found that detecting the arteria comitans as a landmark is novel and may offer an additional tool with the existing methods for sciatic nerve block.

Background and Objectives: Cannabinoids have an expanding presence in medicine. Perioperative patients' perceptions of the effectiveness of these compounds, and acceptance if prescribed for pain, have not been previously described. Our primary objective was to describe patients' beliefs regarding the potential effectiveness of cannabinoids for the treatment of acute and chronic pain, as well as gauge patient acceptance of these compounds if prescribed by a physician. In addition, demographic and pain history data were collected to elucidate the predictors of the aforementioned patient attitudes. Secondarily, we sought to characterize the subgroup of patients who reported marijuana use. Predictors of marijuana use, effectiveness, and adverse effects were also reported for this subgroup., Methods: An anonymous questionnaire was administered to 501 patients in the preoperative registration area at Mount Sinai Hospital, New York, New York. The questionnaire was designed to collect data on patient demographics, presence of pain, pain severity, use of pain medication, history of illicit-drug use, tobacco use, cannabis use, patient beliefs about the potential effectiveness of marijuana for acute and chronic pain and their willingness to use cannabis for pain, if prescribed by a physician. Normality of distributions for continuous variables was assessed with skewness and kurtosis measures. A logistic regression model was used to assess the demographic and medical characteristics of marijuana users compared with nonusers. The effectiveness of marijuana in dealing with pain and adverse effects associated with its use were examined using exploratory principal component analysis., Results: More than 80% of this cohort of preoperative patients believed that marijuana could be at least somewhat effective for the treatment of pain after surgery and would be willing to use cannabinoid compounds if prescribed by their physician. Predictors of positive attitudes toward marijuana included history of marijuana use, pain history, and being a marijuana nonuser of white race. Approximately 27% of the respondents reported a history of marijuana use. Younger patients, those with higher levels of pain in the last 24 hours, and those who found standard therapies to be less effective for their pain were more likely to use marijuana., Conclusions: Patients generally believe that marijuana could be at least somewhat effective for the management of pain and are willing to use cannabinoid compounds for this indication, if prescribed by a physician.

Background: Multiple animal studies suggest that ondansetron ameliorates opioid-induced hyperalgesia and tolerance. In this study, we aimed to determine if the administration of ondansetron prior to spinal anesthesia would have an effect on intrathecal opioid-induced acute opioid tolerance, postoperative pain, and analgesic requirements in patients undergoing cesarean delivery with spinal anesthesia., Methods: Eighty-six patients undergoing elective cesarean delivery were recruited and randomly allocated to receive either 8 mg intravenous ondansetron (n = 44) or placebo (n = 42) in a prospective, double-blind design. All patients received spinal anesthesia consisting of 15 mg bupivacaine, 20 μg of fentanyl, and 100 μg of preservative-free morphine. We used linear mixed-effects models to assess the difference in pain and opioid consumption in the first 24 hours after surgery between the 2 groups., Results: No differences between the 2 groups were found in age, body mass index, American Society of Anesthesiologists physical status scores, duration of surgery, or sensory and motor block characteristics. There was no difference between the 2 groups in postoperative pain scores (P = 0.95) or opioid consumption (P = 0.68)., Conclusions: In patients undergoing cesarean delivery under spinal anesthesia with intrathecal opioids, the administration of ondansetron prior to spinal anesthesia did not significantly affect postoperative pain scores or opioid consumption. Thus, the administration of ondansetron did not have an effect on acute opioid tolerance in our study.

Background and Objectives: A relatively new technique to reduce postoperative pain for total knee arthroplasty is to inject a mixture of 266 mg of liposomal bupivacaine and 125 mg of 0.25% bupivacaine HCl with epinephrine 1:300,000 around the knee joint at the time of surgery. Currently, no publications report serum bupivacaine concentrations over time after periarticular injection of liposomal mixed with free bupivacaine. This information is important to ensure safe serum bupivacaine concentrations are maintained especially when considering supplemental or rescue peripheral nerve blocks., Methods: A total of 40 subjects scheduled for primary unilateral total knee arthroplasty with intraoperative periarticular injection of the liposomal bupivacaine and bupivacaine HCl mixture were included. Total serum bupivacaine concentrations were measured after the last injection at selected time points and calculated by gas chromatography. Quantile regression techniques were used to analyze the data over time. This study is registered with ClinicalTrials.gov (ID NCT02626559)., Results: Peak serum concentration ranged from 0.17 to 1.2 μg/mL and occurred from 10 minutes to 48 hours. Across all time points, the 48-hour interval had the highest mean concentration of total serum bupivacaine at 0.55 μg/mL (SD, 0.27). Quantile regression showed total serum bupivacaine concentrations increased over the 48 hours measured. None of the participants demonstrated signs or symptoms of local anesthetic toxicity., Conclusions: Total serum concentrations of bupivacaine after periarticular administration of liposomal bupivacaine mixed with bupivacaine HCl remained below the described toxicity threshold (2.5 μg/mL) within the first 48 hours, and no patients demonstrated signs or symptoms of toxicity. However, peak serum concentration time was not achieved within the 48-hour interval. Additional studies are needed to describe the course of serum bupivacaine levels after 48 hours and to ascertain the risk of toxicity when combining this method of periarticular injection with peripheral nerve blocks.

Background and Objectives: The objective of this study was to investigate the extent of dermatomal spread following an ultrasound-guided thoracic paravertebral block (PVB) when equal volumes of local anesthetic are injected at 1 versus 5 vertebral levels., Methods: Seventy patients undergoing a unilateral mastectomy were randomized to receive either single or multiple injections of a PVB under real-time ultrasound guidance using a parasagittal approach. The patients in the single-injection group received a PVB at T3-T4 level with 25 mL of 0.5% ropivacaine and 4 subcutaneous sham injections. Patients in the multiple-injection group received 5 injections of a PVB from T1 to T5 level. Five milliliters of 0.5% ropivacaine was injected at each level. Evaluation of the sensory block was carried out 20 minutes following the completion of the PVB., Results: The median (interquartile range) dermatomal spread was not significantly different for the single-injection group (5 [4-6]) compared with the multiple-injection group (5 [5-6]), with a median difference of 0 segments (95% confidence interval, -1 to 0 segments; P = 0.22). The median time to performance of the single-injection PVB was shorter compared with the multiple-injection group (10 minutes), with a mean difference of -4 minutes (95% confidence interval, -6 to -3 minutes; P < 0.001)., Conclusions: An ultrasound-guided single-injection PVB provides equivalent dermatomal spread and duration of analgesia compared with a multiple-injection PVB. The single-injection technique takes less time to perform and hence may be preferred over a multiple-injection technique.The trial was registered prospectively at ClinicalTrials.gov (NCT02852421) on July 15, 2016.

Breast surgery is exceedingly common and may result in significant acute as well as chronic pain. Numerous options exist for the control of perioperative breast pain, including several newly described regional anesthesia techniques, but anesthesiologists have an insufficient understanding of the anatomy of the breast, the anatomic structures disrupted by the various breast surgeries, and the theoretical and experimental evidence supporting the use of the various analgesic options. In this article, we review the anatomy of the breast, common breast surgeries and their potential anatomic sources of pain, and analgesic techniques for managing perioperative pain. We performed a systematic review of the evidence for these analgesic techniques, including intercostal block, epidural administration, paravertebral block, brachial plexus block, and novel peripheral nerve blocks.

Background and Objectives: Truncal blocks have a place within multimodal analgesia techniques in abdominal surgery. The quadratus lumborum block is a new abdominal truncal block used for somatic analgesia of both the upper and lower abdomen. In this prospective, double-blind, randomized study, we aimed to compare quadratus lumborum block and transversus abdominis plane block in pediatric patients undergoing lower abdominal surgery., Methods: Fifty-three children undergoing unilateral inguinal hernia repair or orchiopexy surgery were randomized into 2 groups: transversus abdominis plane block and quadratus lumborum block. All blocks were performed under general anesthesia before surgery. Pain levels were assessed using an FLACC (Face, Legs, Activity, Cry, Consolability) scale., Results: The study included 50 patients, after excluding 3 patients who were not eligible. The number of patients who required analgesia in the first 24 hours postoperatively was significantly lower in the quadratus lumborum block group (P < 0.05). In the quadratus lumborum block group, the postoperative 30-minute and 1-, 2-, 4-, 6-, 12-, and 24-hour FLACC scores were lower compared with those of the transversus abdominis plane block group (P < 0.05). Parent satisfaction scores were higher in the quadratus lumborum block group (P < 0.05)., Conclusions: The results of this study showed that in pediatric patients undergoing unilateral inguinal hernia repair or orchiopexy the quadratus lumborum block provided longer and more effective postoperative analgesia compared with the transversus abdominis plane block., Clinical Trials Registration: The trial was registered prospectively at clinicaltrials.gov (NCT02715999).

Background and Objectives: The placement of thoracic epidurals can be technically challenging and requires a thorough understanding of neuraxial anatomy. Although ultrasound imaging of the thoracic spine has been described, no outcome studies on the use of this imaging have been performed. We evaluated whether preprocedural ultrasound of the thoracic spine would facilitate the process of epidural catheterization., Methods: Subjects undergoing thoracic or upper abdominal surgery with planned thoracic epidural placement at T10 or higher were enrolled in this randomized double-blind study. Subjects were allocated into 1 of 2 groups for preoperative epidural placement: ultrasound guidance (group US) or palpation (group Palp). Subjects randomized to group US had a preprocedural ultrasound examination to identify pertinent spinal anatomy and make appropriate marks on the skin identifying midline and interlaminar spaces for targeted Tuohy needle insertion. Subjects in group Palp had a skin marking performed by palpation alone. Using the skin markings, all epidurals were performed using a loss of resistance to saline technique. Block levels were assessed with ice and pain scores obtained by a blinded nurse in the postanesthesia care unit. The primary outcome was procedural time from needle insertion to loss of resistance in the epidural space., Results: Seventy subjects were recruited and completed the study protocol. The median time for epidural needle placement to achieve loss of resistance in group US and group Palp was 188.5 seconds (interquartile range [IQR], 79.0-515.0) and 242.0 seconds (IQR, 87.0-627.0), respectively (P = 0.188). Using ultrasound to mark the skin overlying the targeted epidural space took a median time of 85 seconds (IQR, 69-113) for group US and 35 seconds (IQR, 27-51) for group Palp (P < 0.001). The number of needle passes was not significantly different between the 2 groups (P = 0.31). The use of ultrasound assistance resulted in a decreased number of needle skin punctures to achieve loss of resistance (P = 0.005). Mean pain scores after surgery were lower in group US compared to group Palp: 3.0 versus 4.7, respectively (P = 0.015)., Conclusions: This is the first randomized study to evaluate the efficacy of preprocedural ultrasound marking for placement of thoracic epidural catheters. We observed that preprocedural ultrasound did not significantly reduce the time required to identify the thoracic epidural space via loss of resistance., Clinical Trials Registration: NCT02785055 (https://clinicaltrials.gov/).

Background and Objectives: Dexmedetomidine has been thought to be an effective adjuvant to local anesthetics in brachial plexus blockade. We sought to clarify the uncertainty that still exists as to its true efficacy., Methods: A meta-analysis of randomized controlled trials was conducted to assess the ability of dexmedetomidine to prolong the duration and hasten the onset of motor and sensory blockade when used as an adjuvant to local anesthesia for brachial plexus blockade versus using local anesthesia alone (control). A search strategy was created to identify eligible articles in MEDLINE, EMBASE, and The Cochrane Library. The methodological quality for each included study was evaluated using the Cochrane Tool for Risk of Bias., Results: Eighteen randomized controlled trials were included in this meta-analysis (n = 1092 patients). The addition of dexmedetomidine significantly reduced sensory block time onset time by 3.19 minutes (95% confidence interval [CI], -4.60 to -1.78 minutes; I = 95%; P < 0.00001), prolonged sensory block duration by 261.41 minutes (95% CI, 145.20-377.61 minutes; I = 100%; P < 0.0001), reduced the onset of motor blockade by 2.92 minutes (95% CI, -4.37 to -1.46 minutes; I = 96%, P < 0.0001), and prolonged motor block duration by 200.90 minutes (CI, 99.24-302.56 minutes; I = 99%; P = 0.0001) as compared with control. Dexmedetomidine also significantly prolonged the duration of analgesia by 289.31 minutes (95% CI, 185.97-392.64 minutes; I = 99%; P < 0.00001). Significantly more patients experienced intraoperative bradycardia with dexmedetomidine (risk difference [RD], 0.06; 95% CI, 0.00-0.11; I = 72%; P = 0.03); however, there was no difference in the incidence of intraoperative hypotension (RD, 0.01; 95% CI, -0.02 to 0.04; I = 3%; P = 0.45). It is important to note that all studies reported that intraoperative bradycardia was either transient in nature or reversible, when needed, with the administration of intravenous atropine., Conclusions: Dexmedetomidine has the ability to hasten the onset and prolong the duration of blockade when used as an adjuvant to local anesthesia for brachial plexus blockade. Considering an analgesic effect to be either decreased pain, a longer duration of analgesic block, or decreased opioid consumption, the addition of dexmedetomidine to local anesthetics for brachial plexus blockade was found to significantly improve analgesia in all 18 included studies. However, patients receiving dexmedetomidine should be continuously monitored for the potentially harmful but reversible adverse effect of intraoperative bradycardia., Level of Evidence: Therapeutic, level I.

Background and Objectives: Patients undergoing major elective ankle surgery often experience pain from the saphenous nerve territory persisting beyond the duration of a single-injection saphenous nerve block. We hypothesized that perineural dexamethasone as an adjuvant for the saphenous nerve block prolongs the duration of analgesia and postpones as well as reduces opioid-requiring pain., Methods: Forty patients were included in this prospective, randomized, controlled study. All patients received a continuous sciatic catheter and were randomized to receive a single-injection saphenous nerve block with 10 mL of 0.5% bupivacaine with 1:200,000 epinephrine with addition of 1 mL of saline or 1 mL of 0.4% (ie, 4 mg) dexamethasone. The primary outcome was duration of saphenous nerve block estimated as the time until the first opioid request. Secondary outcomes were opioid consumption and pain., Results: The mean (SD) duration of the saphenous nerve block until first opioid request was 29.4 (8.4) hours in the dexamethasone group and 23.2 (10.3) hours in the control group (P = 0.048). The median opioid consumption [interquartile range] during the first 24 hours was 0 mg [0-0] versus 1.5 mg [0-14.2] in the dexamethasone and control groups, respectively. Nonparametric comparison of opioid consumption from 0 to 24 hours was statistically significant. The opioid consumption was similar in the two groups in the time interval 24 to 48 postoperative hours., Conclusion: Perineural dexamethasone as an adjuvant for the single-injection subsartorial saphenous nerve block can prolong analgesia and reduce opioid-requiring pain after major ankle surgery.

Abdominal wall blocks rely on the spread of local anesthetic within musculofascial planes to anesthetize multiple small nerves or plexuses, rather than targeting specific nerve structures. Ultrasonography is primarily responsible for the widespread adoption of techniques including transversus abdominis plane and rectus sheath blocks, as well as the introduction of novel techniques such as quadratus lumborum and transversalis fascia blocks. These blocks are technically straightforward and relatively safe and reduce pain and opioid requirements in many clinical settings. The data supporting these outcomes, however, can be inconsistent because of heterogeneity of study design. The extent of sensory blockade is also somewhat variable, because it depends on the achieved spread of local anesthetic and the anatomical course of the nerves being targeted. The blocks mainly provide somatic analgesia and are best used as part of a multimodal analgesic regimen. This review summarizes the anatomical, sonographic, and technical aspects of the abdominal wall blocks in current use, examining the current evidence for the efficacy and safety of each.

Introduction: Postmastectomy pain syndrome (PMPS) is a significant burden for breast cancer survivors. Although multiple therapies have been described, an evolving field of serratus anterior plane blocks has been described in this population. We describe the addition of the deep serratus anterior plane block (DSPB) for PMPS., Methods: Four patients with history of PMPS underwent DSPB for anterior chest wall pain. A retrospective review of these patients' outcomes was obtained through postprocedure interviews., Results: Three of the patients previously had a superficial serratus anterior plane block, which was not as efficacious as the DSPB. The fourth patient had a superficial serratus anterior plane that was difficult to separate with hydrodissection but had improved pain control with a DSPB., Conclusions: We illustrate 4 patients who have benefitted from a DSPB and describe indications that this block may be more efficacious than a superficial serratus plane block. Further study is recommended to understand the intercostal nerve branches within the lateral and anterior muscular chest wall planes.

Background and Objectives: Effective use of postoperative incentive spirometry improves patient outcomes but is limited by pain after thoracic and upper abdominal surgery. Thoracic epidurals are frequently used to provide analgesia and attenuate postoperative pulmonary dysfunction. We hypothesized that, in patients with thoracic epidurals for thoracic and abdominal surgery, high pain scores would be associated with poorer incentive spirometry performance, even when accounting for other variables., Methods: Retrospective study of 468 patients who underwent upper abdominal or thoracic surgery using postoperative thoracic epidural analgesia between June 1, 2009, and August 31, 2013, at a single tertiary academic center. The association between incentive spirometry performance and pain was assessed as the primary outcome. Other independent predictors of incentive spirometry performance were also identified., Results: Postoperative incentive spirometry performance was found to be inversely proportional to pain score, which correlated significantly stronger with deep breathing pain compared with pain at rest (-0.33 vs -0.14 on postoperative day 1; -0.23 vs -0.12 on postoperative day 2). Pain with deep breathing was independently associated with poorer incentive spirometry performance in the multivariable linear regression model (P < 0.0001), as was increasing age, female sex, thoracic surgery, and higher American Society of Anesthesiologists (ASA) physical status score., Conclusions: The present study suggests that pain with deep breathing is more indicative of thoracic epidural efficacy than is pain at rest. Furthermore, incentive spirometry performance could be used as another indicator of thoracic epidural efficacy. This may be particularly useful in patients reporting high pain scores postoperatively.

Background: Exercise creates a variety of psychophysical effects, including altered pain perception. We investigated whether physical exercise reduces postincisional pain and cytokine and N-methyl-D-aspartate receptor 1 (NR1) expression in a rat model of skin/muscle incision and retraction (SMIR)-evoked pain., Methods: Male Sprague-Dawley rats were divided randomly into 4 groups: sham operated, SMIR-sedentary (SS), SMIR-exercise, and sham operated-exercise. On postoperative day 8, trained rats started to run on a treadmill 55 min/d with an intensity of 18 meter/minute (m/min), 5 days per week for 4 weeks. NR1, tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) expressions in the spinal cord as well as mechanical hypersensitivity following SMIR surgery were assessed for 6 to 35 days., Results: On postoperative day 6, SMIR-sedentary rats exhibited a marked hypersensitivity to von Frey stimuli. By contrast, SMIR-operated rats undergoing exercise demonstrated a quick recovery of mechanical hypersensitivity. The levels of TNF-α, IL-6, and NR1 in the spinal cord were significantly increased in SS rats when compared with sham-operated rats on postoperative days 6, 21, and 35 after SMIR surgery. After the 4-week exercise intervention, the SMIR-exercise group showed lower NR1, TNF-α, and IL-6 expression in the spinal cord than those in the SS group., Conclusions: These results suggest that exercise training decreases persistent postsurgical pain caused by SMIR surgery. There appears to be a protective effect, probably relating to the decrease of NR1, TNF-α, and IL-6 expression in the spinal cord of SMIR rats, after exercise intervention.

Background: Epidural analgesia can result in perioperative hypotension in patients having thoracotomy. This randomized prospective study assessed the effects of epidural and paravertebral analgesia on hemodynamics during thoracotomy., Methods: Thirty-two patients were randomized to receive either epidural analgesia (n = 16, 0.25% levobupivacaine and 30 μg/kg morphine) or paravertebral block (n = 16; 0.5% levobupivacaine and 30 μg/kg morphine). Oxygen delivery, stroke volume and systemic vascular resistance indices, heart rate, and mean arterial pressure measurements were performed before administration of local anesthetic, after induction of general anesthesia, institution of 1-lung ventilation, first skin incision, retractor placement, lung-inflation maneuver, and at last skin suture. The primary end point was the volume of the colloid infusion necessary to maintain oxygen delivery index of 500 mL/min per squared meter or higher. Postoperative analgesia was provided immediately after surgery by an infusion of 0.125% levobupivacaine and 20 μg/mL morphine in epidural/paravertebral infusion. Pain, rescue-analgesia consumption, arterial pressure, and heart rate were recorded at 6, 24, and 48 hrs after surgery. Administration of anesthesia and data collection were done by research staff blinded to the regional analgesia technique., Results: The groups did not differ significantly in heart rate, mean arterial blood pressure, or systemic vascular resistance indices. However, to maintain the targeted oxygen delivery index, a greater volume of colloid infusion and phenylephrine were required, respectively, in the epidural than in the paravertebral group (554 ± 50 vs 196 ± 75 mL, P = 0.04; and 40 ± 10 vs 17 ± 4 μg, P = 0.04). Pain intensity before and after respiratory physiotherapy as well as 24 hr rescue piritramide consumption was similar in the epidural (4.1 ± 3.1 mg) and the paravertebral (2.5 ± 1.5 mg) groups (P = 0.14). Systolic blood pressure after 24 and 48 hrs was lower in the epidural group., Conclusions: Under the conditions of our study, continuous paravertebral block resulted in similar analgesia but greater hemodynamic stability than epidural analgesia in patients having thoracotomy. Paravertebral block also required smaller volume of colloids and vasopressors to maintain the target oxygen delivery index (DO2I).

Background: Previously, we have demonstrated that extending a continuous femoral nerve block (cFNB) from overnight to 4 days after total knee arthroplasty (TKA) provides clear benefits during the infusion, but not subsequent to catheter removal. However, there were major limitations in generalizing the results of that investigation, and we subsequently performed a very similar study using a multicenter format, with many health care providers, in patients on general orthopedic wards, thus greatly improving inference of the results to the general population. Not surprisingly, the perioperative/short-term outcomes differed greatly from the first, more limited study. We now present a prospective follow-up study of the previously published, multicenter, randomized controlled clinical trial to investigate the possibility that an extended ambulatory cFNB decreases long-term pain, stiffness, and functional disability after TKA, which greatly improves inference of the results to the general population., Methods: Subjects undergoing TKA received a cFNB with ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to continue either perineural ropivacaine (n=28) or normal saline (n=26). Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis Index preoperatively and then at 7 days, as well as 1, 2, 3, 6, and 12 months after surgery. This index evaluates pain, stiffness, and physical functional disability. For inclusion in the analysis, we required a minimum of 4 of the 6 time points, including day 7 and at least 2 of months 3, 6, and 12., Results: The 2 treatment groups had similar Western Ontario and McMaster Universities Osteoarthritis scores for the mean area-under-the-curve calculations (point estimate for the difference in mean area under the curve for the 2 groups [overnight infusion group - extended infusion group]=3.8; 95% confidence interval, -3.8 to +11.3; P=0.32) and at all individual time points (P>0.05)., Conclusions: This investigation found no evidence that extending an overnight cFNB to 4 days improves (or worsens) subsequent pain, stiffness, or physical function after TKA in patients of multiple centers convalescing on general orthopedic wards., (Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine)

Background: The aim of this study was to determine the minimum effective volume of lidocaine 1.5% with epinephrine 5 μg/mL in 90% of patients (MEV(90)) for single-injection ultrasound-guided infraclavicular block (ICB)., Methods: Using an in-plane technique, a single-injection ultrasound-guided ICB was performed: a 17-gauge, 8-cm Tuohy needle was advanced until the tip was located dorsal to the axillary artery. Volume assignment was carried out using a biased coin design up-and-down sequential method, where the volume of local anesthetic administered to each patient depended on the response of the previous one. In case of failure, the next subject received a higher volume (defined as the previous volume with an increment of 2.5 mL). If the previous patient had a successful block, the next subject was randomized to a lower volume (defined as the previous volume with a decrement of 2.5 mL), with a probability of b=0.11, or the same volume, with a probability of 1-b=0.89. Lidocaine 1.5% with epinephrine 5 μg/mL was used in all subjects. Success was defined, at 30 mins, as a minimal score of 14 of 16 points using a composite scale encompassing sensory and motor block. Patients undergoing surgery of the elbow, forearm, wrist, or hand were prospectively enrolled until 45 successful blocks were obtained., Results: Fifty-five patients were included in the study. Using isotonic regression and bootstrap confidence interval (CI), the MEV(90) for single-injection ultrasound-guided ICB was estimated to be 35 mL (95% CI, 30-37.5 mL). The probability of a successful response at 35 mL was estimated to be 0.91 (95% CI, 0.8-1.0). All patients with a minimal composite score of 14 points at 30 mins achieved surgical anesthesia intraoperatively., Conclusions: For single-injection ultrasound-guided ICB, the MEV(90) of lidocaine 1.5% with epinephrine 5 μg/mL is 35 mL. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents as well as techniques involving multiple injections, a more medial approach to ICB, or precise location of all 3 cords of the brachial plexus., (Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine)

Background and Objectives: Previous data suggest that movement-evoked pain is more closely correlated with pulmonary performance than rest pain beyond 24 hours following lower abdominal surgery. Because adverse alterations in lung physiology are initiated intraoperatively and impact upon pulmonary morbidity, this study tests the hypothesis that movement-evoked pain correlates negatively with pulmonary performance in the immediate postoperative period., Methods: We measured pain at rest and pain evoked by sitting, forced expiration, and coughing as well as peak expiratory flow (PEF), forced expiratory volume in 1 second, and forced vital capacity for the first 3 hours after laparoscopic cholecystectomy in 65 patients., Results: Immediately after surgery, all pain measures were significantly correlated with PEF with a medium effect size. Also, sitting-evoked pain and cough-evoked pain were significantly more intense than rest pain. Pain intensity improved significantly over the first 3 postoperative hours., Conclusions: Considering these and previous results, pulmonary function tests such as PEF should be considered for more routine use as functional surrogates of movement-evoked pain in analgesic trials of thoracic and abdominal surgery. Mechanisms of immediate postoperative movement-evoked pain may differ from those in effect at later time points after which tissue inflammation and spinal sensitization develop. Because pain adversely impacts upon postoperative rehabilitation, these results further imply that aggressive treatment of movement-evoked pain could improve the outcome of postoperative rehabilitation measures if both are implemented very early after surgery.

Background and Objectives: It is unclear whether the severity of postoperative pain may affect patients' quality of recovery in the immediate postoperative period (within 2 weeks of surgery)., Methods: This was a prospective, observational study in patients undergoing elective radical retropubic prostatectomy. All patients received a standardized intraoperative general or spinal anesthetic followed by intravenous patient-controlled analgesia. Visual analog scores for pain at rest, pain with activity, and nausea along with the QoR, an instrument validated to assess quality of recovery in the postoperative period, and Brief Fatigue Inventory were assessed on postoperative days 1 to 3, 7, and 30. The Epworth Sleepiness Scale was assessed on postoperative days 7 and 30., Results: We found that the severity of pain both at rest and with activity correlated with a decrease in quality of recovery as assessed by the QoR., Conclusions: Our findings suggest that an increase in postoperative pain is correlated with a decrease in a patient's quality of recovery in the immediate postoperative period.

Background and Objectives: Schizophrenic patients may have less sensitivity to pain; however, pain insensitivity in schizophrenia has not been adequately evaluated. We investigated current perception threshold (CPT) and postoperative pain intensity in patients with long-standing and treated schizophrenia and control patients., Methods: We measured CPTs for 2,000 Hz, 250 Hz, and 5 Hz and postoperative pain intensity using a visual analogue scale (VAS) in 50 chronic schizophrenic patients who were on chronic phenothiazine derivatives (> 10 years) and for 25 control patients., Results: CPTs for 2,000 Hz, 250 Hz, and 5 Hz in schizophrenic patients were 334.2 +/- 112.2, 303.9 +/- 117.1, and 165.0 +/- 72.3, respectively. CPTs for 2,000 Hz, 250 Hz, and 5 Hz in schizophrenic patients were significantly higher than those of control patients. VAS pain scores of schizophrenic patients were 4.0 +/- 1.7 at 2 hours post-operatively and 3.8 +/- 1.5 at 5 hours postoperatively, which were significantly (P < .05) lower than those (5.0 +/- 1.6 and 5.1 +/- 1.9) of the control group., Conclusions: Chronic schizophrenic patients have increased current perception threshold and lower VAS pain scores in postoperative pain compared with control patients.

Background and Objectives: We aimed to determine the following in an experimental acute pain model in sheep: (1) whether multimodal analgesia with intravenous fentanyl and ketorolac was more effective than fentanyl alone; (2) whether secondary hyperalgesia (central sensitization) occurred in adjacent (foreleg) dermatomes after thoracic surgery; (3) whether ketorolac used preemptively influenced the development of secondary hyperalgesia after surgery., Methods: Changes in primary nociception were measured by increases to tolerated pressure, applied to the foreleg by a blunt pin, before foreleg withdrawal occurred. Changes to breath-to-breath interval and estimated end-tidal CO2 were used as indices of respiratory effects. Study 1 (n = 6) compared the paired responses to acute nociception after ketorolac (90 mg) or saline (control) pretreatment, followed by fentanyl (graded, 0 mg to 1.5 mg). Study 2 (n = 6) used a cross-over of ketorolac (90 mg) or saline (control) 24 hours and 1 hour, respectively, before a standardized thoracotomy incision, followed by antinociceptive testing with ketorolac (90 mg) and fentanyl (0.6 mg) daily over 4 days., Results: In study 1, fentanyl produced naloxone-antagonizable antinociception and respiratory depression. Ketorolac did not affect fentanyl antinociception, except for prolonging antinociception at the highest dose; it did not affect the respiratory effects. In study 2, preemptive ketorolac had no effect on the postoperative antinociceptive or respiratory effects of fentanyl. The pharmacokinetics of fentanyl were unaltered by ketorolac., Conclusions: The results obtained in this acute pain model found no significant evidence of a fentanyl-ketorolac interaction, of central sensitization as shown by secondary hyperalgesia, or of a preemptive analgesic effect.