Soft, bioresorbable coolers for reversible conduction block of peripheral nerves.

Implantable devices capable of targeted and reversible blocking of peripheral nerve activity may provide alternatives to opioids for treating pain. Local cooling represents an attractive means for on-demand elimination of pain signals, but traditional technologies are limited by rigid, bulky form factors; imprecise cooling; and requirements for extraction surgeries. Here, we introduce soft, bioresorbable, microfluidic devices that enable delivery of focused, minimally invasive cooling power at arbitrary depths in living tissues with real-time temperature feedback control. Construction with water-soluble, biocompatible materials leads to dissolution and bioresorption as a mechanism to eliminate unnecessary device load and risk to the patient without additional surgeries. Multiweek in vivo trials demonstrate the ability to rapidly and precisely cool peripheral nerves to provide local, on-demand analgesia in rat models for neuropathic pain.

Reduction of leakage from insertion site during continuous femoral nerve block with catheter-through-needle versus catheter-over-needle technique for postoperative analgesia after total knee arthroplasty: a randomized controlled trial.

BACKGROUND: Continuous femoral nerve block (CFNB) is a common procedure used for postoperative analgesia in total knee arthroplasty. Continuous nerve block using a conventional needle (catheter-through-needle/CTN) is complicated by leakage of the anesthetic from the catheter insertion site. A different type of needle (catheter-over-needle/ CON) is now available, which is believed to reduce leakage as the diameter of the catheter is larger than that of the needle. The purpose of this study was to compare the incidence of leakage from the catheter insertion site during CFNB while using CTN and CON for postoperative analgesia after total knee arthroplasty (TKA). METHODS: This prospective, randomized, single-blinded controlled study included 60 patients who were scheduled for TKA at our facility between May 2016 and November 2017. Patients were randomly allocated to the CTN or CON groups. All patients in both groups received CFNB and sciatic nerve block for postoperative analgesia. The administration of 0.16% levobupivacaine mixed with 6 mg of indigo carmine (a dye added to easily identify leakage) was started at 6 ml/h at the end of surgery. The primary outcome was the incidence of leakage from the catheter insertion site. We further investigated the degree of leakage, the incidence of catheter migration, pain scores using the numerical rating scale at 48 h postoperatively, and the number of days until the operated knee could be flexed 120 degrees postoperatively in both groups. RESULTS: The CON group had a significantly lower incidence and degree of leakage from the catheter insertion site. There were no significant differences in other measurement outcomes. CONCLUSIONS: Use of CON reduces the incidence of leakage from the catheter insertion site during CFNB in the use of postoperative analgesia for total knee arthroplasty. Future research is needed to determine additional benefits of using CON related to decreased leakage. TRIAL REGISTRATION: The study was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry ( UMIN000021537 ), prospectively registered on 18 March 2016.

Safety of Continuous Erector Spinae Catheters in Chest Trauma: A Retrospective Cohort Study.

BACKGROUND: The erector spinae block is an efficacious analgesic option for the management of rib fracture--related pain. Despite there being minimal published data specifically addressing the safety profile of this block, many societies have made statements regarding its safety and its use as an alternative to traditional regional anesthesia techniques in patients at risk of complications. The primary aim of this study was to characterize the safety profile of erector spinae plane block catheters by determining the incidence of early complications. The secondary aim of this study was to characterize the incidence of late adverse events, as well as the erector spinae plane block catheter failure rate. METHODS: We analyzed electronic medical record data of patients who had an erector spinae plane block catheter inserted for the management of rib fractures between November 2017 and September 2020. To assess early adverse events, data collection included hypotension, hypoxemia, local anesthetic systemic toxicity, and pneumothorax thought to be associated with erector spinae plane block catheter insertion. Late complications included catheter site infection and catheter site hematoma. RESULTS: A total of 224 patients received 244 continuous erector spinae catheters during the study period. After insertion of the erector spinae, there were no immediate complications such as hypotension, hypoxia, local anesthetic toxicity, or pneumothorax. Of all blocks inserted, 7.7% were removed due to catheter failure (8.4 per 100 catheters; 95% confidence interval [CI], 5.1-13.9 per 100 catheters). This resulted in a failure rate of 1.9 per 1000 catheter days (95% CI, 1.1-6.7 catheter days). Late complications included 2 erythematous catheter sites and 2 small hematomas not requiring intervention. The incidence of a minor late complication was 16.7 per 1000 catheters (95% CI, 6.1-45.5 per 1000 catheters). CONCLUSIONS: This study supports the statements made by regional anesthesia societies regarding the safety of the erector spinae plane block. Based on the results presented in this population of trauma patients, the erector spinae plane block catheter is a low-risk analgesic technique that may be performed in the presence of abnormal coagulation status or systemic infection.

Analgesic effects of erector spinae plane block can differ according to needle size: A case report.

RATIONALE: Unlike brachial plexus block, erector spinae plane block (ESPB) does not target specific nerves, so the analgesic effect may differ depending on the extent of diffusion of local anesthetic. Therefore, needle size, which can affect the diffusion of local anesthetic, may be an important factor in the analgesic effect. PATIENT CONCERNS: Four patients with end-stage renal disease on hemodialysis received vascular surgery due to arteriovenous fistula occlusion. Vascular bypass surgery was performed on the axillary vein. DIAGNOSES: Four patients with end-stage renal disease on hemodialysis were diagnosed with arteriovenous fistula occlusion. One in 4 patients was diagnosed with diaphragm paralysis after ESPB, and the other 3 did not develop diaphragm paralysis. INTERVENTIONS: ESPB was conducted by ultrasound using a 25- or 22-gauge needle at the C7 level. The extent of nerve blockade was determined based on cold sensation, and diaphragm excursion and thickness were measured via ultrasound. OUTCOMES: The analgesic effect was excellent in 2 patients treated using a 22-gauge needle, but was poor in 2 other patients treated with a 25-gauge needle. LESSONS: ESPB at the C7 level can cause diaphragm paralysis, and needle size may affect the extent of diffusion of local anesthetic.

Comparison of catheter-over-needle and catheter-through-needle methods in ultrasound-guided continuous femoral nerve block: A prospective, randomized controlled trial.

BACKGROUND: The catheter-through-needle (CTN) method involves the insertion of a catheter with an outer diameter smaller than the initial puncture hole. We investigated whether the catheter-over-needle (CON) method is more effective than the CTN method in local anesthetic leakage at the catheter insertion site and catheter dislodgement, and how it affects postoperative pain management. METHODS: Seventy patients scheduled to undergo continuous femoral nerve block for pain control following total knee arthroplasty were enrolled and randomized to receive a perineural catheterization with either the CTN method (group CTN) or CON method (group CON). After ultrasound-guided catheterization, the transparent securement dressing was attached. The study compared the CON and CTN methods in terms of leakage at the catheter insertion site, catheter dislodgement, and postoperative analgesic efficacy for 48 hours postoperatively. RESULTS: Leakage at the catheter insertion site was significantly lower in the group CON (P < .05), while catheter dislodgement was not significantly different between the groups. The other adverse events were not different between the groups. The procedure time was significantly shorter in group CON (P < .05). No significant intergroup differences were observed 48 hours postoperatively in the visual analog scales, the number of patients requiring additional analgesics, and the number of times a bolus dose was injected with an injection pump. CONCLUSION: The CON method was able to shorten the procedure time while reducing the incidence of leakage at the catheter insertion site than the CTN method, and showed similar effects in postoperative pain management.

Comparison of transversus abdominis plane catheters with thoracic epidurals for cost and length of stay in open colorectal surgeries: a cohort study.

BACKGROUND: Thoracic epidural analgesia has long been a common method of postoperative analgesia for major open abdominal surgeries and is frequently used within enhanced recovery after surgery programs. An alternative postoperative analgesia method is the single shot transversus abdominis plane block, which has shown promising outcomes with respect to total length of stay, cost, pain scores, and decreased opioid usage. However, far less is known regarding continuous transversus abdominis plane analgesia using catheters. We evaluated the total cost-effectiveness of transversus abdominis plane catheter analgesia compared to thoracic epidural analgesia for patients undergoing open colorectal surgeries within the enhanced recovery after surgery program at our institution. METHODS: This cohort study included patients booked under the colorectal surgery enhanced recovery after surgery program from November 2016 through March 2018 who received either bilateral transversus abdominis plane catheters (n = 52) or thoracic epidural analgesia (n = 24). RESULTS: There was no difference in total direct cost (p = 0.660) and indirect cost (p = 0.220), and median length of stay (p = 0.664) in the transversus abdominis plane catheter group compared to the thoracic epidural group. Additionally, the transversus abdominis plane catheter group received significantly less morphine equivalents compared to the thoracic epidural group (p = 0.008) and had a lower mean body mass index (p = 0.019). There was no significant difference between the two groups for age (p = 0.820), or sex (p = 0.330). CONCLUSIONS: Transversus abdominis plane catheter analgesia is not associated with increased cost or longer hospital stays when compared to thoracic epidural analgesia in patients undergoing open colorectal surgery within an enhanced recovery after surgery program. Furthermore, transversus abdominis plane catheter analgesia led to decreased opioid consumption while maintaining similar pain scores, suggesting similar pain control between the two modalities.

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

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

Pulmonary Comorbidities Are Associated with Increased Major Complication Rates Following Indwelling Interscalene Nerve Catheters for Shoulder Arthroplasty.

Pulmonary comorbidities and ASA physical status class III and IV can significantly increase the rate of major complications after ISC placement. Patients with an underlying pulmonary comorbidity or lung disease (chronic obstructive pulmonary disease, asthma, or obstructive sleep apnea) have a 2.2-fold increased risk of having any complication and a 2.4-fold increased risk of having a major pulmonary complication compared to those without pulmonary comorbidities. Patients with pulmonary comorbidities may benefit from alternative pain management strategies to avoid complications in the early postoperative period.

Combination Preemptive Peripheral Nerve Block in Limb Surgery. A Prospective Study.

Background and objectives: Patients often suffer from moderate to severe pain during the early recovery period in orthopedic surgery. We investigated the impact of a single-shot preoperative peripheral nerve block (PNB) on post-anesthesia recovery parameters and interleukin (IL)-6 level during limb surgery. Materials and Methods: A prospective randomized controlled study was conducted, and patients scheduled for limb surgery were recruited. Sixty patients were randomly assigned to either the PNB group or control group, who received morphine as a primary analgesic. The peak verbal numeric rating scale (NRS) score in the post-anesthesia care unit (PACU) was evaluated as a primary outcome. We also recorded rescue analgesics requirement and wake-up time from anesthesia in the PACU. In addition, the change of plasma IL-6 level after incision was measured. Results: Fifty-two patients completed the study, 27 and 25 cases in the PNB and control group, respectively. Preemptive PNB significantly reduced peak NRS score in the PACU compared to control group. Lower rescue analgesics requirement and rapid wake-up from anesthesia were also noted in PNB group. The IL-6 concentration increased less in the PNB group at 2 h after incision. Conclusions: Preemptive PNB attenuates IL-6 expression 2 h after incision and improves pain management in the PACU. PNB was considered as an essential part of pain management in limb surgery.

Ultrasound-Guided Midpoint Transverse Process to Pleura Nerve Block for Medical Thoracoscopy: A Case Report.

We performed the midpoint transverse process to pleura (MTP) block in a patient with a recurrent pleural effusion requiring medical thoracoscopy, drainage of pleural effusion, talc poudrage, and placement of tunneled pleural catheter under sedation while in the left lateral decubitus position. Forty milliliters of a combination of bupivacaine hydrochloride and lidocaine, with dexamethasone and clonidine as adjuvants, was injected at the T6 level under ultrasound guidance with satisfactory intra- and postoperative analgesia.

Ultrasound-guided transmuscular quadratus lumborum catheters for elective caesarean section: A protocol for a single-centre, double-blind randomised trial.

BACKGROUND: Management of moderate-to-severe post-operative pain after elective caesarean section (ECS) is internationally primarily based on either epidural catheters or opioids. However, both techniques are associated with some undesirable adverse events. Bilateral transmuscular quadratus lumborum (TQL) block has proven to reduce opioid consumption significantly in the first 24 post-operative hours following ECS and prolong time to first opioid (TFO) (Hansen CKD, Steingrimsdottir M, Laier GE, et al. Reg Anesth Pain Med. 2019; 10.1136/rapm-2019-100540). We present a randomised controlled trial aiming to investigate whether continuous analgesia via bilateral TQL catheters can prolong TFO after ECS. METHODS: This study is a double-blind, randomised, placebo-controlled trial. Patients should be 18 years or older and scheduled for ECS under spinal anaesthesia to be included. Main exclusion criteria are inability to cooperate, excessive daily intake of opioids and difficult ultrasound visualisation of muscular and fascial structures. Participants are randomised to receive ultrasound-guided injection of either 30 mL ropivacaine 0.2% bilaterally and an elastomeric pump containing 0.2% ropivacaine, or 30 mL saline bilaterally and an elastomeric pump containing saline, 2 hours after catheter placement. The primary endpoint is TFO. Secondary outcomes include pain intensity on a numeric rating scale (NRS), accumulated morphine consumption during 24 hours, displacement frequency of catheters and morphine-related adverse events. RECRUITMENT PERIOD: Four patients were included from September 2018 to November 2018. Inclusion was resumed in June 2019 and will continue until 24 patients with useful data have been included in the trial. Expected inclusion period is 10-14 months. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03663478. EudraCT: 2017-003625-15.

Comparison of two methods of continuous femoral nerve block with elastomeric pump after total knee arthroplasty.

BACKGROUND: The best method of continuous femoral nerve block (CFNB) after total knee arthroplasty (TKA) has not been determined. The study aimed to assess the effectiveness of CFNB based on patient-controlled regional analgesia (PCRA) with basal infusion of local anesthetic in decreasing pain and providing functional restoration after TKA and to compare it with the method of basal infusion only. METHODS: The prospective randomized controlled trial included 90 patients who were divided into three groups. Group I: control group with basal morphine infusion, without CFNB. Group II: CFNB with continuous infusion of ropivacaine. Group III: CFNB with basal infusion of ropivacaine plus boluses. Intensity of pain, morphine consumption, patient satisfaction, adverse effects, the effect on range of motion (ROM) in the knee joint, as well as using the measure of a distance were analyzed. RESULTS: A lower level of pain was observed (P < 0.005), as was reduced opioid consumption (P < 0.005), a greater ROM (P < 0.005), a longer distance covered (P < 0.005), and a smaller incidence of nausea in group III when compared with group II. No statistically significant difference was noted between the groups in terms of other side effects. There was higher satisfaction between group II and group III on days 1 and 2 (P < 0.08). CONCLUSIONS: It was demonstrated that CFNB with continuous infusion of 5 mL h-1 of 0.2% ropivacaine plus 5 mL as a bolus causes a greater reduction in pain intensity and opioid consumption; it also shortens the time of functional restoration in comparison to perineural infusion of 5mL h-1 only during the first 4 days after TKA and constitutes an effective and safe alternative to using an electronic pump.

Impact of supraglottic device with assist ventilation under general anesthesia combined with nerve block in uniportal video-assisted thoracoscopic surgery.

BACKGROUND: With the improvement of anesthesia and surgical techniques, supraglottic device with assist ventilation under general anesthesia (GA) combined with nerve block is gradually applied to video-assisted thoracoscopic surgery. However, the safety of assist ventilation has not been fully confirmed, and a large number of samples should be studied in clinical exploration. METHODS: The subjects included 120 patients, undergoing elective thoracoscopic GA, with American Society of Anesthesiologists (ASA) physical status I or II, were randomly divided into 3 groups, 40 cases in each group. Group T: received double-lumen bronchial intubation, Group I: received intercostal nerve block using a supraglottic device, Group P: received paravertebral nerve block using a supraglottic device. Mean arterial pressure, heart rate, saturation of pulse oximetry and surgical field satisfaction, general anesthetic dosage and recovery time were recorded before induction of GA (T0), at the start of the surgical procedure (T1), 15 minutes later (T2), 30 minutes later (T3), and before the end of the surgical procedure (T4). Static and dynamic pain rating (NRS) and Ramsay sedation score were recorded 2 hours after surgery (T5), 12 hours after surgery (T6), 24 hours after surgery (T7), time to get out of bed, hospitalization time and cost, patient satisfaction and adverse reactions. RESULTS: There was no significant difference with the surgical visual field of the 3 groups (P > .05). The MAP, HR and SpO2 of the 3 groups were decreased from T2 to T3 compared with T0(P < .05). Compared with group T: the total dosage of GA was reduced in group I and group P, the recovery time was shorter, the time to get out of bed was earlier (P < .05), the hospitalization time was shortened, the hospitalization cost was lower, and the patient satisfaction was higher (P < .05). The static and dynamic NRS scores were lower from T5 to T7 (P < .05). Ramsay sedation scores were higher (P < .05), and the incidence of adverse reactions was lower (P < .05). Comparison between group I and group P: Dynamic NRS score of group P was lower from T6 to T7 (P < .05). CONCLUSION: Supraglottic device with assist ventilation under general anesthesia combined with nerve block in uniportal video-assisted thoracoscopic surgery is safe and feasible.

Description of ultrasound-guided quadratus lumborum block technique and evaluation of injectate spread in canine cadavers.

OBJECTIVE: To describe a quadratus lumborum (QL) block technique in canine cadavers and the spread of injectate. STUDY DESIGN: Prospective, randomized, descriptive, experimental anatomic study. ANIMALS: A group of 12 adult canine cadavers. METHODS: Gross and ultrasound anatomy of the sublumbar musculature and the relationship with the spinal nerves was studied in two cadavers. Bilateral ultrasound-guided injections were performed in eight cadavers in the fascial plane between the QL and psoas muscle using a dye-lidocaine solution [low volume (LV) 0.15 mL kg-1 or high volume (HV) 0.3 mL kg-1]. The ultrasound transducer was positioned caudal and parallel to the proximal aspect of the last rib, and an insulated needle was introduced in-plane using a ventrolateral to dorsomedial approach. Dissections were performed to determine the number of spinal nerves successfully stained (>1 cm) and the presence of injectate in the epidural space or abdominal cavity. Additionally, two cadavers were transversally cryosectioned after QL injection. RESULTS: Ventral branches of the last thoracic and first three lumbar spinal nerves ran between the bundles of the QL muscle and between the QL and psoas muscles. The target fascial plane was ultrasonographically identified and filled with the dye solution following all injections. Ventral branches of the thirteenth thoracic and first, second and third lumbar nerves were stained by 0.0%, 71.4%, 100%, 100%, and 25%, 100%, 100%, 100% using LV and HV, respectively. Multisegmental spread stained the lumbar sympathetic trunk on 0 (0-3) and 3 (0-4) vertebral levels with LV and HV, respectively. No abdominal or epidural spread was identified. CONCLUSION AND CLINICAL RELEVANCE: Although no significant differences were found, HV resulted in a higher percentage of stain on spinal nerves and sympathetic trunk than LV. Further studies are warranted to determine if the QL block provides somatic and visceral abdominal analgesia in dogs.

Vulnerability of different nerves to intrafascicular injection by different needle types and at different approach angles: a mathematical model.

BACKGROUND AND OBJECTIVES: We assume that intrafascicular spread of a solution can only occur if a large enough portion of the distal needle orifice is placed inside the fascicle. Our aim is to present and evaluate a mathematical model that can calculate the theoretical vulnerability of fascicles, analyzing the degree of occupancy of the needle orifice in fascicular tissue by performing simulations of multiple positions that a needle orifice can take inside a cross-sectional nerve area. METHODS: We superimposed microscopic images of two routinely used nerve block needles (22-gauge, 15° needle and 22-gauge, 30° needle) over the microscopic images of cross-sections of four nerve types photographed at the same magnification. Fascicular tissue that was overlapped between 80% and 100% by a needle orifice was considered at risk to possible intrafascicular injection. The effect of three angular approaches was evaluated. RESULTS: There were statistical differences between the vulnerability of fascicular tissue depending on nerve type, the bevel angle of the needle and the angle approach. Fascicular vulnerability was greater in nerve roots of the brachial plexus after using a 22-gauge 30° needle, as was choosing a 45° angle approach to the longitudinal axis of the nerve. CONCLUSIONS: Our results suggest that clinicians may want to consider needle insertion angle and bevel type as they perform peripheral nerve blocks. Furthermore, researchers may want to consider this mathematical model when estimating vulnerabilities of various nerves, needle types and angles of approach of needles to nerves.

Ultrasound-guided erector spinae plane block in canine cadavers: relevant anatomy and injectate distribution.

OBJECTIVE: To investigate the distribution and nerve staining of two volumes of lidocaine-dye solution after ultrasound-guided erector spinae plane (ESP) injections in canine cadavers. STUDY DESIGN: Experimental cadaveric study. ANIMALS: A total of nine canine cadavers. METHODS: ESP injections were performed between the longissimus thoracis muscle and the dorsolateral edge of the ninth thoracic transverse process. Two cadavers were transversally cryosectioned after unilateral ESP injections [0.6 mL kg-1; high volume (HV)]. In seven cadavers, bilateral ESP injections with HV or low volume (0.3 mL kg-1; LV) were performed. Gadodiamide was added to the injectate for two cadavers and magnetic resonance imaging (MRI) was performed pre- and post-injection. Injectate distribution and nerve staining of the branches of the spinal nerves were recorded after gross anatomical dissection. The thoracic paravertebral and epidural spaces were examined for dye solution. RESULTS: Cryosections, MRI and gross dissections showed that the injectate spread dorsally to the transverse processes, over the ventromedial aspect of the longissimus thoracis muscle where the medial and lateral branches of the dorsal branches of the spinal nerves are located. LV and HV stained a median (range) of 4 (2-7) and 4 (3-8) medial branches, respectively (p = 0.52). LV and HV stained 4 (2-5) and 5 (4-7) lateral branches (p = 0.26), respectively. Ventral branches were not stained, and dye was not identified in the epidural or paravertebral spaces. CONCLUSIONS: and clinical relevance Medial and lateral branches were consistently stained over several spinal segments. The number of nerves stained was not different with HV or LV, and the ventral branches of the spinal nerves were not stained in any cadaver. ESP block may find a clinical application to desensitize structures innervated by the medial and lateral branches of the dorsal branches of the thoracic spinal nerves.

Ultrasound guided supra-inguinal Fascia Iliaca Compartment Blocks in hip fracture patients: An alternative technique.

INTRODUCTION: In the Emergency Department, regional anesthesia is increasingly used in elderly patients with hip fractures. An example is a Fascia Iliaca Compartment Block (FICB). Traditionally, this block is administered below the inguinal ligament. There is no Emergency Department data regarding effectivity of an alternative, more cranial approach above the inguinal ligament. The objective was to determine analgesic effects of an ultrasound-guided supra-inguinal FICB in hip fracture patients in the Emergency Department. METHODS: This case series included all Emergency Department hip fracture patients who were treated with a supra-inguinal FICB during a period of 10 months. All data were recorded prospectively. Primary study outcome was decrease in Numerical Rating Scale (NRS) pain scores 60 min after the FICB. Secondary outcomes included the proportion of patients achieving 1.5 NRS points decrease at 60 min; NRS differences at 30 and 120 min compared to baseline; need for additional analgesia and occurrence of adverse events. RESULTS: A total of 22 patients were included in the study. At 60 min median NRS pain scores decreased from 6.0 to 3.0 (p < 0.001). Of all patients, a total of 59% achieved a decrease in 1.5 NRS points after 60 min. Median pain scores at 30 and 120 min were 4.0 (Interquartile Range (IQR) 2.0-5.0) and 2.5 (IQR 0.8-3.0). Seven patients (31.8%) required additional opioid analgesia after the FICB. No adverse events were recorded. CONCLUSION: An ultrasound-guided supra-inguinal FICB decreases NRS pain scores in hip fracture patients both clinically relevant and statistically significantly after 60 min. CLINICAL TRIAL REGISTRATION: The study was registered in the ISRCTN database (ISRCTN74920258).

The Ultrasound Anatomy of Nerves in the Interscalene Groove: Can We Reliably Distinguish the Nerve Structures for Needle Placement During Nerve Blocks?

In the interscalene groove, nerve structures are in close proximity and may not be visible as separate structures, increasing the risk of insertion of the needle tip within the epineurium. We evaluated whether experienced regional anesthesiologists can distinguish between nerve elements lying in close proximity on ultrasound images.Brachial plexus elements from 4 nonpreserved cadavers were arranged in a water bath. Ultrasound images of the nerve roots and trunks were taken. Regional anesthesiologists and residents were asked whether they could distinguish the nerves as 2 separate structures and if they could identify a pair of nerve roots versus a single trunk.Attending anesthesiologists reported the ability to discriminate 2 nerve structures when a 2-mm space was arranged between them in 54% of images; however, when in direct contact, this recognition was significantly lower. The residents reported a higher ability to discriminate the 2 nerves in all scenarios. In addition, the attending anesthesiologists successfully identified paired nerve roots versus nerve trunks in 70% of the images, significantly higher than chance (P = 0.01), whereas the fraction of correct resident responses was not significantly different from guessing.When nerves were placed in close proximity, experienced regional anesthesiologists had difficulty identifying them as separate structures and were incorrect nearly one-third of the time in discriminating 2 closely positioned roots versus a nerve trunk. This underscores the importance of cautious needle insertion into the interscalene groove, where nerve elements are often juxtaposed one to another.