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Persistent and chronic pain after cancer surgery is a complex clinical problem. The etiology of pain in these cases is often multifactorial and, in addition to the surgery itself, can include or overlap with other painful syndromes such as direct effects of tumors, neuropathic pain, and pain syndromes secondary to chemotherapy and/or radiation.There is a growing body of literature which suggests that treating pain in the acute and subacute periods can prevent chronic pain, an important step in reducing the morbidity of this clinical problem. This review describes the incidence of persistent pain after cancer surgery, its pathophysiology, and treatment considerations. Additional research on diagnostic criteria, pathophysiology, and novel medications, restorative therapies, and interventional treatments will be essential to continue to reduce the clinical burden of persistent and chronic perioperative pain after cancer surgery.

BackgroundThere is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques.MethodsWe conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement.ResultsSixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified.ConclusionsHarmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice.

We previously reported that the duration of hospitalization was not different between isoflurane and sevoflurane. But more plausible consequences of using soluble volatile anesthetics are delayed emergence from anesthesia and prolonged stays in the postanesthesia care unit (PACU). We therefore compared isoflurane and sevoflurane on emergence time and PACU duration.We reanalyzed data from 1498 adults who participated in a previous alternating intervention trial comparing isoflurane and sevoflurane. Patients, mostly having colorectal surgery, were assigned to either volatile anesthetic in 2-week blocks that alternated for half a year. Emergence time was defined as the time from minimum alveolar concentration fraction reaching 0.3 at the end of the procedure until patients left the operating room. PACU duration was defined from admission to the end of phase 1 recovery. Treatment effect was assessed using Cox proportional hazards regression, adjusted for imbalanced baseline variables.A total of 674 patients were given isoflurane, and 824 sevoflurane. Emergence time was slightly longer for isoflurane with a median (quartiles) of 16 minutes (12-22 minutes) vs 14 minutes (11-19 minutes) for sevoflurane, with an adjusted hazard ratio of 0.81 (97.5% CI, 0.71-0.92; P.001). Duration in the PACU did not differ, with a median (quartiles) of 2.6 hours (2.0-3.6 hours) for isoflurane and 2.6 hours (2.0-3.7 hours) hours for sevoflurane. The adjusted hazard ratio for PACU discharge time was 1.04 (97.5% CI, 0.91-1.18; P = .56).Isoflurane prolonged emergence by only 2 minutes, which is not a clinically important amount, and did not prolong length of stay in the PACU. The more soluble and much less-expensive anesthetic isoflurane thus seems to be a reasonable alternative to sevoflurane.

Compare transversus abdominis plane (TAP) blocks with liposomal bupivacaine were to epidural analgesia for pain at rest and opioid consumption in patients recovering from abdominal surgery.ERAS pathways suggest TAP blocks in preference to epidural analgesia for abdominal surgery. However, the relative efficacies of TAP blocks and epidural analgesia remains unknown.Patients having major abdominal surgery were enrolled at six sites and randomly assigned 1:1 to thoracic epidural analgesia or bilateral/4-quadrant TAP blocks with liposomal bupivacaine. Intravenous opioids were used as needed. Non-inferiority margins were a priori set at 1 point on an 11-point pain numeric rating scale for pain at rest and at a 25% increase in postoperative opioid consumption.Enrollment was stopped per protocol at 3rd interim analysis after crossing an a priori futility boundary. 498 patients were analyzed (255 had TAP blocks and 243 had epidurals). Pain scores at rest in patients assigned to TAP blocks were significantly non-inferior to those given epidurals, with an estimated difference of 0.09 points (CI: -0.12, 0.30; noninferiority P 0.001). Opioid consumption during the initial 3 postoperative days in TAP patients was not non-inferior to epidurals, with an estimated ratio of geometric means of 1.37 (CI: 1.05, 1.79; non-inferiority P = 0.754). However, the absolute difference was only 21 mg morphine equivalents over the 3 days. Patients with epidurals were more likely to experience mean arterial pressures65 mmHg than those given TAP blocks: 48% versus 31%, P = 0.006.Pain scores at rest during the initial three days after major abdominal surgery were similar. Patients assigned to TAP blocks required more opioid then epidural patients but had less hypotension. Clinicians should reconsider epidural analgesia in patients at risk from hypotension.ClinicalTrials.gov Identifier: NCT02996227.

Background: Rhomboid intercostal block is a newer technique for chest wall analgesia and can be an effective alternative to thoracic epidurals and paravertebral blocks. We performed a rhomboid intercostal block after sternoclavicular joint reconstruction surgery. Case Report: A healthy 26-year-old male who had chronic right sternoclavicular joint instability was scheduled for right medial clavicle resection with sternoclavicular joint allograft reconstruction. We performed a right interscalene single-shot nerve block followed by a rhomboid intercostal block with catheter placement under ultrasound guidance. The patient's pain was well controlled postoperatively with minimal use of opioids. Conclusion: Rhomboid intercostal block with brachial plexus block is a potential option for analgesia after sternoclavicular joint reconstruction surgery.

Continuous blood pressure monitoring may facilitate early detection and prompt treatment of hypotension. We tested the hypothesis that area under the curve (AUC) mean arterial pressure (MAP)65 mm Hg is reduced by continuous invasive arterial pressure monitoring.Adults having noncardiac surgery were randomly assigned to continuous invasive arterial pressure or intermittent oscillometric blood pressure monitoring. Arterial catheter pressures were recorded at 1-minute intervals; oscillometric pressures were typically recorded at 5-minute intervals. We estimated the arterial catheter effect on AUC-MAP65 mm Hg using a multivariable proportional odds model adjusting for imbalanced baseline variables and duration of surgery. Pressures65 mm Hg were categorized as 0, 1-17, 18-91, and91 mm Hg × minutes of AUC-MAP65 mm Hg (ie, no hypotension and 3 equally sized groups of increasing hypotension).One hundred fifty-two patients were randomly assigned to arterial catheter use and 154 to oscillometric monitoring. For various clinical reasons, 143 patients received an arterial catheter, while 163 were monitored oscillometrically. There were a median [Q1, Q3] of 246 [187, 308] pressure measurements in patients with arterial catheters versus 55 (46, 75) measurements in patients monitored oscillometrically. In the primary intent-to-treat analysis, catheter-based monitoring increased detection of AUC-MAP65 mm Hg, with an estimated proportional odds ratio (ie, odds of being in a worse hypotension category) of 1.78 (95% confidence interval [CI], 1.18-2.70; P = .006). The result was robust over an as-treated analysis and for sensitivity analyses with thresholds of 60 and 70 mm Hg.Intraoperative blood pressure monitoring with arterial catheters detected nearly twice as much hypotension as oscillometric measurements.

Background and objectivesBoth posterior quadratus lumborum (QL) and erector spinae plane (ESP) blocks have been described as new truncal interfascial plane blocks. Distribution of injectate is influenced by fascial anatomy; therefore, different injection sites may produce similar spread. This anatomic study was designed to test the hypothesis that a posteromedial QL block at L2 level will more closely resemble a low thoracic ESP block when compared with the posterolateral approach at L2 level.MethodsLeft-sided ESP blocks were performed in six cadavers at T10–11. Three of these cadavers received right-sided posteromedial QL block at L2, while the other three received right-sided posterolateral QL block at L2. All injections were composed of 20 mL methylcellulose 0.5 % mixed with India ink and 10 mL of Omnipaque (Iohexol) 240 mg/mL. CT 24 hours after injection and cadaver dissection were used to evaluate injectate spread.ResultsCephalocaudal spread of injectate by CT and cadaveric dissection was highly correlated (r=0.85 [95% CI 0.51 to 0.95]). Cadaver dissection showed ESP injectate spread deep to the muscle (mean [SD]) 11.7 (2.3) levels compared with 7.3 (1.2) levels for posterolateral QL and 9.7 (1.5) for posteromedial QL (p=0.04 overall, with a statistically significant pairwise difference between ESP and posterolateral QL only). The subcostal nerve and dorsal rami were commonly involved in most blocks, but the paravertebral space and ventral rami had inconsistent involvement. The lumbocostal ligament limited cranial spread from the posterlateral QL block approach.ConclusionsThe posteromedial QL block at L2 produces more cranial spread beyond the lumbocostal ligament than the posterolateral QL block, and this spread is comparable with a low thoracic ESP block. Both posterior QL and ESP blocks show unreliable spread of injectate to the paravertebral space and ventral rami, but the dorsal rami were frequently covered.

Objective The anatomical landmarks method is currently the most widely used technique for epidural needle insertion and is faced with multiple difficulties in certain patient populations. Real-time ultrasound guidance has been recently used to aid in epidural needle insertion, with promising results. Our aim was to test the feasibility, success rate, and satisfaction associated with a novel real-time ultrasound-guided lumbar epidural needle insertion in the transverse interlaminar view. Design Prospective descriptive trial on a novel approach. Setting Operating room and preoperative holding area at a tertiary care hospital. Subjects Adult patients presenting for elective open prostatectomy and planned for surgical epidural anesthesia. Methods Consented adult patients aged 30–80 years scheduled for open prostatectomy under epidural anesthesia were enrolled. Exclusion criteria included allergy to local anesthetics, infection at the needle insertion site, coagulopathy, and patient refusal. A curvilinear low-frequency (2–5 MHz) ultrasound probe and echogenic 17-G Tuohy needles were used by one of three attending anesthesiologists. Feasibility of epidural insertion was defined as a 90% success rate within 10 minutes. Results Twenty-two patients were enrolled into the trial, 14 (63.6%) of whom found the process to be satisfactory or very satisfactory. The median time to perform the block was around 4.5 minutes, with an estimated success rate of 95%. No complications related to the epidural block were observed over the 48 hours after the procedure. Conclusions We demonstrate the feasibility of a novel real-time ultrasound-guided epidural with transverse interlaminar view.

The local anesthetic injectate spread with fascial plane blocks and corresponding clinical outcomes may vary depending on the site of injection. We developed and evaluated a supra-iliac approach to the anterior quadratus lumborum (QL) block and hypothesized that this single injection might successfully block the lumbar and sacral plexus in cadavers and provide analgesia for patients undergoing hip surgery. Ultrasound-guided bilateral supra-iliac anterior QL blocks were performed with 30 mL of India ink dye in six fresh adult cadavers. Cadavers were subsequently dissected to determine distribution of the dye. In five patients undergoing hip surgery, a unilateral supra-iliac anterior QL block with 25 mL ropivacaine 0.5% followed by a continuous catheter infusion was performed. Patients were clinically assessed daily for block efficacy. The cadaveric injections showed consistent dye involvement of the majority of the branches of the lumbar plexus, including the femoral nerve, lateral femoral cutaneous nerve, ilioinguinal nerve, and iliohypogastric nerve. The majority of cadaveric specimens (83%) also exhibited thoracic paravertebral spread of dye to the T10 level. No specimens showed L5 or sacral nerve root staining or caudal spread below L5. All patients had effective analgesia for total hip surgery and a T11–L3 sensory level following the initial bolus of local anesthetic as well as during the period of continuous catheter infusion. This cadaveric study and case series show that a supra-iliac approach to the anterior QL block involved T10-–L3 nerve territories and dermatomal coverage with no sacral plexus spread. This technique may have clinical utility for analgesia in hip surgery.

BACKGROUND Neuraxial anesthesia improves components of the Virchow's triad (hypercoagulability, venous stasis, and endothelial injury) which are key pathogenic contributors to venous thrombosis in surgical patients. However, whether neuraxial anesthesia reduces the incidence of venous thromboembolism (VTE) remain unclear. We therefore tested the primary hypothesis that neuraxial anesthesia reduces the incidence of 30-day VTE in adults recovering from orthopedic surgery. Secondarily, we tested the hypotheses that neuraxial anesthesia reduces 30-day readmission, 30-day mortality, and the duration of postoperative hospitalization. METHODS Inpatient orthopedic surgeries from American College of Surgeons National Surgical Quality Improvement Program database (2011-2015) in adults lasting more than 1 hour with either neuraxial or general anesthesia were included. Groups were matched 1:1 by propensity score matching for appropriate confounders. Logistic regression model was used to assess the effect of neuraxial anesthesia on 30-day VTE, 30-day mortality, and readmission, while Cox proportional hazard regression model was used to assess its effect on length of stay. RESULTS Neuraxial anesthesia decreased odds of 30-day VTE (odds ratio 0.85, 95% confidence interval, 0.78-0.95; P = .002) corresponding to number-needed-to-treat of 500. Although there was no difference in 30-day mortality, neuraxial anesthesia reduced 30-day readmission (odds ratio 0.90, 98.3% confidence interval, 0.85-0.95; P < .001) corresponding to number-needed-to-treat of 250 and had a shortened hospitalization (2.87 vs 3.11; P < .001). CONCLUSIONS Neuraxial anesthesia appears to provide only weak VTE prophylaxis, but can be offered as an adjuvant to current thromboprophylaxis in high-risk patients.

A review of anatomy, potential mechanisms of action, and techniques and summary of clinical evidence for quadratus lumborum block.

In the case of open urological surgeries, analgesic coverage at mid thoracic dermatomal levels is required. As shown in cadaveric studies, the site of QL block injection is an important determinant of the extent of dye spread and presumably local anesthetic dermatomal coverage. In this case series, we evaluated dermatomal blockade and analgesic efficacy of a subcostal approach to anterior QL block following open urological surgeries. Twenty-two adult patients undergoing renal transplant surgery (60%) and open nephrectomy (40%) received unilateral ultrasound-guided subcostal anterior QL block with catheter insertion. Sensory level, pain score (numeric rating scale, NRS), local anesthetic consumption, and opioid consumption (morphine equivalent dose, MED) were assessed daily for 3 days. The block achieved sensory blockade between T6-7 and L1-2. The most frequently affected dermatomes were T8 -T12 and the number of blocked segments was 3 (mean 2.8). The median (interquartile range Q1, Q3) of NRS pain score was 3.7 (2.8-5.5), 3.3 (2.4-4.7), 2.9 (1.9-3.6), and 2.3 (1.0-4.2) on POD0, POD1, POD2, and POD3, respectively. Our preliminary data showed that the subcostal approach to anterior QL block provides appropriate thoracic dermatome level needed for analgesia following open urological surgical procedures between T6-7 and L1-2.

Study Objective We report a modified block technique aimed at obtaining upper midline and lateral abdominal wall analgesia: the external oblique intercostal (EOI) block. Design A cadaveric study and retrospective cohort study assessing the potential analgesic effect of the EOI block. Setting Cadaver lab and operating room. Patients Two unembalmed cadavers and 22 patients. Interventions Bilateral ultrasound-guided EOI blocks on cadavers with 29 mL of bupivacaine 0.25% with 1 mL of India ink; single-injection or continuous EOI blocks in patients. Measurements Dye spread in cadavers and loss of cutaneous sensation in patients. Main Results In the cadaveric specimens, we identified consistent staining of both lateral and anterior branches of intercostal nerves from T7 to T10. We also found consistent dermatomal sensory blockade of T6–T10 at the anterior axillary line and T6–T9 at the midline in patients receiving the EOI block. Conclusions We demonstrate the potential mechanism of this technique with a cadaveric study that shows consistent staining of both lateral and anterior branches of intercostal nerves T7–T10. Patients who received this block exhibited consistent dermatomal sensory blockade of T6–T10 at the anterior axillary line and T6–T9 at the midline. This block can be used in multiple clinical settings for upper abdominal wall analgesia.

Chronic pain imposes a tremendous economic burden of up to US$635 billion per year in terms of direct costs (such as the costs of treatment) and indirect costs (such as lost productivity and time away from work). In addition, the initiation of opioids for pain is associated with a more than doubling of pharmacy and all-cause medical costs. The high costs of chronic pain are particularly relevant for anesthesiologists because surgery represents an inciting event that can lead to chronic pain and long-term opioid use. While the presence of risk factors and an individual patient’s postoperative pain trajectory may predict who is at high risk for chronic pain and opioid use after surgery, to date, there are few interventions proven to reduce these risks. One promising approach is the transitional pain service. Programs like this attempt to bridge the gap between acute and chronic pain management, provide continuity of care for complicated acute pain patients after discharge from the hospital, and offer interventions for patients who are on abnormal trajectories of pain resolution and/or opioid use. Despite awareness of chronic pain after surgery and the ongoing opioid epidemic, there are few examples of successful transitional pain service implementation in the USA. Key issues and concerns include financial incentives and the required investment from the hospital or healthcare system. We present an economic analysis and discussion of important considerations when developing a business plan for a transitional pain service.

Background Epidural block are often used for analgesia after open nephrectomy surgery. Subcostal anterior quadratus lumborum block may be an alternative. We therefore tested the hypothesis that the continuous subcostal anterior quadratus lumborum block is noninferior to epidural block for analgesia in patients having open partial nephrectomies. Methods Adults having open partial nephrectomies were randomly allocated to epidural or unilateral subcostal anterior quadratus lumborum block. The joint primary outcomes were opioid consumption measured in morphine equivalents and pain measured on a numeric rating scale (0-10) from postanesthesia care unit (PACU) until 72 hours after surgery. The noninferiority deltas were 30% for opioid consumption and 1 point on a 0-10 scale for pain. Secondary outcomes included patient global assessment of pain management on the third postoperative day, the number of antiemetic medication doses through the third postoperative day, duration of PACU stay, and postoperative duration of hospitalization. Results Twenty-six patients were randomized to anterior quadratus lumborum block and 29 to epidural analgesia. Neither pain scores nor opioid consumption in the quadratus lumborum patients were noninferior to epidural analgesia. At 72 hours, mean ± standard deviation pain scores in subcoastal anterior quadratus lumborum block and epidural group were 4.7 ± 1.8 and 4.1 ± 1.7, with an estimated difference in pain scores of 0.62 (95% confidence interval [CI], 0.74-1.99; noninferiority P = .21). The median [Q1, Q3] opioid consumption was more than doubled in quadratus lumborum patients at 70 mg [43, 125] versus 30 mg [18, 75] in the epidural group with an estimated ratio of geometric means of 1.69 (95% CI, 0.66-4.33; noninferiority P = .80). Patient global assessment and duration of PACU and hospital stays did not differ significantly in the 2 groups. Conclusions We were unable to show that subcostal anterior quadratus lumborum block are noninferior to epidural analgesia in terms of pain scores and opioid consumption for open partial nephrectomies. Effectiveness of novel blocks should be rigorously tested in specific surgical setting before widespread adoption.

Fascial plane blocks (FPBs) are regional anesthesia techniques in which the space (“plane”) between two discrete fascial layers is the target of needle insertion and injection. Analgesia is primarily achieved by local anesthetic spread to nerves traveling within this plane and adjacent tissues. This narrative review discusses key fundamental anatomical concepts relevant to FPBs, with a focus on blocks of the torso. Fascia, in this context, refers to any sheet of connective tissue that encloses or separates muscles and internal organs. The basic composition of fascia is a latticework of collagen fibers filled with a hydrated glycosaminoglycan matrix and infiltrated by adipocytes and fibroblasts; fluid can cross this by diffusion but not bulk flow. The plane between fascial layers is filled with a similar fat-glycosaminoglycan matric and provides gliding and cushioning between structures, as well as a pathway for nerves and vessels. The planes between the various muscle layers of the thorax, abdomen, and paraspinal area close to the thoracic paravertebral space and vertebral canal, are popular targets for ultrasound-guided local anesthetic injection. The pertinent musculofascial anatomy of these regions, together with the nerves involved in somatic and visceral innervation, are summarized. This knowledge will aid not only sonographic identification of landmarks and block performance, but also understanding of the potential pathways and barriers for spread of local anesthetic. It is also critical as the basis for further exploration and refinement of FPBs, with an emphasis on improving their clinical utility, efficacy, and safety.

For decades, the catheter through needle technique has been used for regional anesthesia. The catheter over needle (CON) technique was recently introduced for peripheral nerve[1 2][1] but has not been described for epidural placement. Using CON technique, the needle is removed from the assembly and

Background: Renal autotransplantation is a complex procedure performed for various indications such as treatment of renal vascular and urologic lesions and loin pain hematuria syndrome (LPHS). Because of the rarity of the procedure, few reports have been published, and little is known about anesthetic management and postoperative outcomes of patients with LPHS. The goal of this study was to review and describe all cases of renal autotransplantation performed at Cleveland Clinic during a specified period, focusing on anesthetic management and postoperative 30-day outcomes. Methods: We performed a retrospective review of the records of all patients who underwent renal autotransplantation from 2005 to 2014 at the Cleveland Clinic and collected demographic, anesthetic, surgical, and postoperative data. Results: A total of 64 patients underwent renal autotransplantation from 2005 to 2014. The most frequent indications were nephrolithiasis and LPHS. General endotracheal anesthesia with epidural for pain control was used in 47% of cases. Median duration of anesthesia was 528 minutes. Most patients were sent to a regular nursing floor postoperatively, but 28% of patients required intensive care unit admission. Two patients developed graft ischemia, and 1 patient developed graft failure requiring nephrectomy. No anesthetic-related complications and no mortality were associated with this procedure during the study. Conclusion: Renal autotransplantation is a safe option for patients with LPHS. Additional studies are needed to assess the effect of intraoperative anesthetic management on outcomes in this patient population.

Objective The optimal continuous peripheral nerve block (CPNB) technique for total hip arthroplasty (THA) that maximizes both analgesia and mobility is unknown. Continuous erector spinae plane (ESP) blocks were implemented at our institution as a replacement for fascia iliaca (FI) catheters to improve our THA clinical pathway. We designed this study to test the hypothesis that this change will increase early postoperative ambulation for elective primary THA patients. Methods We identified all consecutive primary unilateral THA cases six months before and six months after the clinical pathway change to ESP catheters. All other aspects of the THA clinical pathway and multimodal analgesic regimen including perineural infusion protocol did not change. The primary outcome was total ambulation distance (meters) on postoperative day 1. Other outcomes included total ambulation on postoperative day 2, combined two-day ambulation distance, pain scores, opioid consumption, inpatient length of stay, and minor and major adverse events. Results Eighty-eight patients comprised the final sample (43 FI and 45 ESP). Postoperative day 1 total ambulation distance was greater for the ESP group compared with the FI group (median [10th–90th percentiles] = 24.4 [0.0–54.9] vs 9.1 [0.7–45.7] meters, respectively, P = 0.036), and two-day ambulation distance was greater for the ESP group compared with the FI group (median [10th–90th percentiles] = 68.6 [9.0–128.0] vs 46.6 [3.7–104.2] meters, respectively, P = 0.038). There were no differences in pain scores, opioid use, or other outcomes. Conclusions Replacing FI catheters with continuous ESP blocks within a clinical pathway results in increased early ambulation by elective primary THA patients.

To the Editor We thank Dr Ohgoshi[1][1] for their interest in our recent article[2][2] which investigates the spread of erector spinae plane (ESP) injections in cadaveric models. We concur that the location of injection is critical in the efficacy of their intended analgesic effect. To adequately

Spectral analysis of ultrasound radiofrequency backscatter has the potential to identify intercostal blood vessels during ultrasound-guided placement of paravertebral nerve blocks and intercostal nerve blocks. Autoregressive models were used for spectral estimation, and bandwidth, autoregressive order and region-of-interest size were evaluated. Eight spectral parameters were calculated and used to create random forests. An autoregressive order of 10, bandwidth of 6 dB and region-of-interest size of 1.0 mm resulted in the minimum out-of-bag error. An additional random forest, using these chosen values, was created from 70% of the data and evaluated independently from the remaining 30% of data. The random forest achieved a predictive accuracy of 92% and Youden's index of 0.85. These results suggest that spectral analysis of ultrasound radiofrequency backscatter has the potential to identify intercostal blood vessels. (jokling@siue.edu) © 2018 World Federation for Ultrasound in Medicine and Biology.

Ultrasound-guided interfascial plane blocks are a recent development in modern regional anesthesia research and practice and represent a new route of transmission for local anesthetic to various anatomic locations, but much more research is warranted. Before becoming overtaken with enthusiasm for these new techniques, a deeper understanding of fascial tissue anatomy and structure, as well as precise targets for needle placement, is required. Many factors may influence the ultimate spread and quality of resulting interfascial plane blocks, and these must be understood in order to best integrate these techniques into contemporary perioperative pain management protocols.

Study objective Our goal was to evaluate the effect of diabetic severity and duration on preoperative residual gastric volume. Secondarily we compared ultrasonic estimates of residual gastric volume with actual volume determined by aspiration during endoscopy. Design This was a prospective, observational cohort study that included adults with a history of diabetes mellitus and/or opioid use scheduled for gastrointestinal endoscopic procedures. Setting Endoscopy unit at Cleveland Clinic Main Campus from 2017 to 2019. Participant Adults scheduled for upper endoscopy with or without colonoscopy. Intervention and measurements Residual gastric volumes were primarily determined by aspiration during endoscopy, and secondarily estimated with ultrasound. We evaluated the relationship between gastric residual volume and preoperative HBA1C concentration and duration of diabetes. Secondarily, we conducted an agreement analysis between the two gastric volume measurement techniques. Main results Among 145 enrolled patients, 131 were diabetic and 17 were chronic opioid users. Among 131 diabetic patients, the mean ± SD HbA1c was 7.2 ± 1.5% and the median (Q1, Q3) duration of diabetes was 8.5 (3, 15) years. Neither HbA1c nor duration of diabetes was associated with residual gastric volume. The adjusted mean ratio of residual gastric volume was 1.07 (98.3% CI: 0.89, 1.28; P = 0.38) for 1% increase in HbA1c concentration, and 0.84 (98.3% CI: 0.63, 1.14; P = 0.17) for each 10-year increase induration of diabetes. The median [Q1–Q3] absolute difference between gastric ultrasound measurement and endoscopic measurement was 25 [15, 65] ml. Conclusions In this prospective observational cohort study, neither the duration nor severity of diabetes influenced preoperative residual gastric volume. Gastric ultrasound can help identify patients who have excessive residual volumes despite overnight fasting.

The dermatomal level of analgesia achieved with quadratus lumborum blocks varies according to the location of injection. The most commonly used approaches are either at the postero-lateral aspect or anterior to the quadratus lumborum muscle.To determine whether the site of injection of contrast dye around the quadratus lumborum muscle of cadavers affects the extent and mechanism of dye spread.Observational human cadaver study.Cleveland Clinic cadaveric laboratory.Six fresh human cadavers.The cadavers received either a posterior quadratus lumborum block or an anterior subcostal quadratus lumborum block on each side.Cadavers were dissected to determine the extent of dye spread.The posterior quadratus lumborum block approach revealed consistently deep staining of the iliohypogastric, ilioinguinal, subcostal nerve, T11 to 12 and L1 nerve roots. In addition, staining of the middle thoracolumbar fascia was seen in all specimens but only variable staining of T10 nerve roots. The anterior subcostal quadratus lumborum block approach in all specimens demonstrated predictable deep staining of the iliohypogastric and ilioinguinal nerves, subcostal nerves, T11 to 12 and L1 nerve roots, and in addition traversing the arcuate ligaments to involve T9 to 12 nerve roots with variable staining of higher thoracic nerve roots.Our cadaveric study demonstrates that injection of dye on the posterior aspect of quadratus lumborum muscle led to injectate spread through the lateral and posterior abdominal wall but with limited cranial spread, whereas the anterior approach produced broader coverage of the lower to mid-thoracic region. Clinical translation of these findings to determine the practical significance is warranted.

Epidural anesthesia and analgesia has a reported failure rate ranging from 13% to 32%. We describe a technique using colour Doppler and M-mode ultrasonography to determine the position of the epidural catheter after placement in adults. This retrospective review included 37 adult patients who received postoperative epidural analgesia and underwent technically difficult epidural catheter placement. The demographic characteristics, type of surgery, use of ultrasonography, method of insertion, intervertebral level, and success of epidural localization using colour Doppler were noted for each patient. Pain scores on postoperative day 1 and the presence of a patchy block were also reviewed. Colour Doppler study helped to indicate the catheter’s path from the skin to the epidural space during saline injection in 33 patients (89%). Saline flow within the epidural space (catheter tip confirmation) was successfully detected with colour Doppler in 25 patients (67.5%) and with M-mode ultrasonography in 28 patients (75%). Appropriate dermatomal analgesia was noted in 35 patients (94.5%) during local anesthetic infusion. Our preliminary data suggest the feasibility of using colour Doppler and M-mode ultrasonography to confirm proper epidural catheter placement.

Quadratus lumborum (QL) block is a novel approach for managing postoperative pain in patients undergoing abdominal and hip surgeries. The QL blocks have the potential to produce sensory blockade and analgesia along the lower thoracic and lumbar regions. There is currently no general consensus on the mechanism of action of QL blockade. The subendothoracic fascial spread and direct spread to the lumbar plexus branches are the proved mechanism. The available limited literature and experiences demonstrate that QL blocks have the potential to produce sensory blockade and analgesia along the lower thoracic and lumbar regions, and can potentially be an analgesic modality for abdominal and hip surgeries.

Although epidural analgesia is widely used for pain relief, it is associated with a significant failure rate. Loss of resistance technique, tactile feedback from the needle, and surface landmarks are traditionally used to guide the epidural needle tip into the epidural space (EDS). The aim of this narrative review is to critically appraise new and emerging technologies for identification of EDS and their potential role in the future. The PubMed, Cochrane Central Register of Controlled Clinical Studies, and Web of Science databases were searched using predecided search strategies, yielding 1048 results. After careful review of abstracts and full texts, 42 articles were selected to be included. Newer techniques for localization of EDS can be broadly classified into techniques that (1) guide the needle to the EDS, (2) identify needle entry into the EDS, and (3) confirm catheter location in EDS. An ideal method should be easy to learn and perform, easily reproducible with high sensitivity and specificity, identifies inadvertent intrathecal and intravascular catheter placements with ease, feasible in perioperative setting and have a cost-benefit advantage. Though none of them in their current stages of development qualify as an ideal method, many show tremendous potential. Some techniques are useful in patients with difficult spinal anatomy and infants, and thus are complementary to traditional methods. In addition to improving the existing technology, future research should aim at proving the superiority of these techniques over traditional methods, specifically regarding successful EDS localization, better safety profile, and a favorable cost-benefit ratio.

BackgroundCervical erector spinae plane (ESP) block has been described to anesthetize the brachial plexus (BP), however, the mechanism of its clinical effect remains unknown. As the prevertebral fascia encloses the phrenic nerves, BP and erector spinae muscles to form a prevertebral compartment, a local anesthetic injected in the cervical ESP could potentially spread throughout the prevertebral compartment. This study utilizes cadaveric models to evaluate the spread of ESP injections at the C6 and C7 levels to determine whether the injection can reach the BP and its surrounding structures.MethodsFor each of the five cadavers, an ESP injection posterior to the transverse process of C6 was performed on one side, and an ESP injection posterior to the transverse process of C7 was performed on the contralateral side. Injections were performed under ultrasound guidance and consisted of a 20 mL mixture of 18 mL water and 2 mL India ink. After cadaver dissection, craniocaudal and medial-lateral extent of the dye spread in relation to musculoskeletal anatomy as well as direct staining relevant nerves was recorded. The degree of dye staining was categorized as “deep,” “faint,” or “no.”ResultsThe phrenic nerve was deeply stained in 1 injection and faintly stained in 2 injections. Caudally, variable staining of C8 (100%) and T1 (50%) roots were seen. Faintly staining at C4 root was only seen in one sample (10%). There was variable staining of the anterior scalene muscles (40%) anterior to the BP and the rhomboid intercostal plane caudally (30%).ConclusionsUltrasound-guided cervical (C6 and C7) ESP injections consistently stain the roots of the BP and dorsal rami. This study supports the notion that the cervical ESP block has the potential to provide analgesia for patients undergoing shoulder and cervical spine surgeries.

Paravertebral and intercostal nerve blocks have experienced a resurgence in popularity. Ultrasound has become the gold standard for visualization of the needle during injection of the analgesic, but the intercostal artery and vein can be difficult to visualize. We investigated the use of spectral analysis of raw radiofrequency (RF) ultrasound signals for identification of the intercostal vessels and six other tissue types in the intercostal and paravertebral spaces. Features derived from the one-dimensional spectrum, two-dimensional spectrum, and cepstrum were used to train four different machine learning algorithms. In addition, the use of the average normalized spectrum as the feature set was compared with the derived feature set. Compared to a support vector machine (SVM) (74.2%), an artificial neural network (ANN) (68.2%), and multinomial analysis (64.1%), a random forest (84.9%) resulted in the most accurate classification. The accuracy using a random forest trained with the first 15 principal components of the average normalized spectrum was 87.0%. These results demonstrate that using a machine learning algorithm with spectral analysis of raw RF ultrasound signals has the potential to provide tissue characterization in intercostal and paravertebral ultrasound.

Objective To compare analgesia and opioid consumption for patients undergoing primary total hip arthroplasty with preoperative posterior quadratus lumborum block with patients who did not receive quadratus lumborum block. Methods The medical records of patients undergoing unilateral total hip arthroplasty between January 1st, 2017 and March 31, 2018 were reviewed, and 238 patients were included in the study. The primary outcome was postoperative opioid consumption in the first 24 postoperative hours. Secondary outcomes were intraoperative, post anesthesia care unit, and 48-hour opioid consumption, postoperative pain Visual Analog Scale scores, and post-anesthesia care unit length of stay. Primary and secondary endpoint data were compared between patients undergoing primary total hip arthroplasty with preoperative posterior quadratus lumborum block with patients who did not receive quadratus lumborum block. Results For the patients who received quadratus lumborum block, the 24-hour total oral morphine equivalent (milligram) requirements were lower (53.82mg±37.41), compared to the patients who did not receive quadratus lumborum block (77.59mL±58.42), with p=0.0011. Opioid requirements were consistently lower for the patients who received quadratus lumborum block at each additional assessment time point up to 48 hours. Pain Visual Analog Scale scores were lower up to 12 hours after surgery for the patients who received a posterior quadratus lumborum block, and the post-anesthesia care unit length of stay was shorter for the patients who received quadratus lumborum block. Conclusion Preoperative posterior quadratus lumborum block for primary total hip arthroplasty is associated with decreased opioid requirements up to 48 hours, decreased Visual Analog Scale pain scores up to 12 hours, and shorter post-anesthesia care unit length of stay. Level of evidence: III RESUMO Objetivo Comparar a analgesia e o uso de opioides em pacientes submetidos à artroplastia total do quadril primária com bloqueio pré-operatório do quadrado lombar posterior e pacientes que não receberam o bloqueio do quadrado lombar. Métodos Revisamos os prontuários de pacientes submetidos à artroplastia total do quadril unilateral entre 1º de janeiro de 2017 e 31 de março de 2018, e 238 pacientes foram incluídos no estudo. O desfecho primário foi o consumo de opioides no pós-operatório nas primeiras 24 horas. Os desfechos secundários foram consumo de opioide no intraoperatório, na sala de recuperação pós-anestésica e nas primeiras 48 horas, escores de Escala Visual Analógica de dor pós-operatória, e tempo de permanência na recuperação pós-anestésica. Os desfechos primário e secundários foram comparados entre os pacientes submetidos à artroplastia total do quadril primária com bloqueio pré-operatório do quadrado lombar posterior e aqueles que não receberam o bloqueio do quadrado lombar. Resultados Para o grupo que recebeu o bloqueio, as doses totais de morfina por via oral em 24 horas foram menores (53,82mg±37,41) em comparação ao grupo sem bloqueio (77,59mg±58,42), com p=0,0011. A utilização de opioides foi consistentemente menor para o grupo que recebeu o bloqueio em cada tempo adicional de avaliação até 48 horas. Os escores da Escala Visual Analógica até 12 horas após a cirurgia para os pacientes que receberam o bloqueio do quadrado lombar posterior e o tempo de permanência na sala de recuperação pós-anestésica foram menores para o grupo que recebeu o bloqueio. Conclusão O bloqueio anestésico do quadrado lombar posterior para artroplastia total do quadril primária está associado à diminuição do uso de opioides nas primeiras 48 horas, diminuição do escore de dor da Escala Visual Analógica em até 12 horas, e menor tempo de permanência na sala de recuperação pós-anestésica. Nível de evidência: III