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Background Ultrasound-guided percutaneous cryoneurolysis is an analgesic technique in which a percutaneous probe is used to reversibly ablate a peripheral nerve(s) using exceptionally low temperature, and has yet to be evaluated with randomized, controlled trials. Pain after mastectomy can be difficult to treat, and the authors hypothesized that the severity of surgically related pain would be lower on postoperative day 2 with the addition of cryoanalgesia compared with patients receiving solely standard-of-care treatment. Methods Preoperatively, participants at one enrolling center received a single injection of ropivacaine, 0.5%, paravertebral nerve block at T3 or T4, and perineural catheter. Participants subsequently underwent an active or sham ultrasound–guided percutaneous cryoneurolysis procedure of the ipsilateral T2 to T5 intercostal nerves in a randomized, patient- and observer-masked fashion. Participants all received a continuous paravertebral block with ropivacaine, 0.2%, until the early morning of discharge (usually postoperative day 2). The primary endpoint was the average pain level measured using a 0 to 10 numeric rating scale the afternoon of postoperative day 2. Participants were followed for 1 yr. Results On postoperative day 2, participants who had received active cryoneurolysis (n = 31) had a median [interquartile range] pain score of 0 [0 to 1.4] versus 3.0 [2.0 to 5.0] in patients given sham (n = 29): difference –2.5 (97.5% CI, –3.5 to –1.5), P < 0.001. There was evidence of superior analgesia through month 12. During the first 3 weeks, cryoneurolysis lowered cumulative opioid use by 98%, with the active group using 1.5 [0 to 14] mg of oxycodone compared with 72 [20 to 120] mg in the sham group (P < 0.001). No oral analgesics were required by any patient between months 1 and 12. After 1 yr chronic pain had developed in 1 (3%) active compared with 5 (17%) sham participants (P < 0.001). Conclusions Percutaneous cryoneurolysis markedly improved analgesia without systemic side effects or complications after mastectomy. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Supplemental Digital Content is Available in the Text. A 6-day ambulatory continuous peripheral nerve block reduces phantom limb pain and pain-induced physical and emotional dysfunction for at least 4 weeks after treatment., Phantom limb pain is thought to be sustained by reentrant neural pathways, which provoke dysfunctional reorganization in the somatosensory cortex. We hypothesized that disrupting reentrant pathways with a 6-day-long continuous peripheral nerve block reduces phantom pain 4 weeks after treatment. We enrolled patients who had an upper- or lower-limb amputation and established phantom pain. Each was randomized to receive a 6-day perineural infusion of either ropivacaine or normal saline. The primary outcome was the average phantom pain severity as measured with a Numeric Rating Scale (0-10) at 4 weeks, after which an optional crossover treatment was offered within the following 0 to 12 weeks. Pretreatment pain scores were similar in both groups, with a median (interquartile range) of 5.0 (4.0, 7.0) for each. After 4 weeks, average phantom limb pain intensity was a mean (SD) of 3.0 (2.9) in patients given local anesthetic vs 4.5 (2.6) in those given placebo (difference [95% confidence interval] 1.3 [0.4, 2.2], P = 0.003). Patients given local anesthetic had improved global impression of change and less pain-induced physical and emotional dysfunction, but did not differ on depression scores. For subjects who received only the first infusion (no self-selected crossover), the median decrease in phantom limb pain at 6 months for treated subjects was 3.0 (0, 5.0) vs 1.5 (0, 5.0) for the placebo group; there seemed to be little residual benefit at 12 months. We conclude that a 6-day continuous peripheral nerve block reduces phantom limb pain as well as physical and emotional dysfunction for at least 1 month.

BackgroundParavertebral and serratus plane blocks are both used to treat pain following breast surgery. However, it remains unknown if the newer serratus block provides comparable analgesia to the decades-old paravertebral technique.MethodsSubjects undergoing unilateral or bilateral non-mastectomy breast surgery were randomized to a single-injection serratus or paravertebral block in a subject-masked fashion (ropivacaine 0.5%; 20 mL unilateral; 16 mL/side bilateral). We hypothesized that (1) analgesia would be non-inferior in the recovery room with serratus blocks (measurement: Numeric Rating Scale), and (2) opioid consumption would be non-inferior with serratus blocks in the operating and recovery rooms. In order to claim that serratus blocks are non-inferior to paravertebral blocks, both hypotheses must be at least non-inferior.ResultsWithin the recovery room, pain scores for participants with serratus blocks (n=49) had a median (IQR) of 4.0 (0–5.5) vs 0 (0–3.0) for those with paravertebral blocks (n=51): 0.95% CI −3.00 to −0.00; p=0.001. However, the difference in morphine equivalents did not reach statistical significance for superiority with the serratus group consuming 14 mg (10–19) vs 10 mg (10–16) for the paravertebral group: 95% CI −4.50 to 0.00, p=0.123. Since the 95% CI lower limit of −4.5 was less than our prespecified margin of −2.0, we failed to conclude non-inferiority of the serratus block with regard to opioid consumption.ConclusionsSerratus blocks provided inferior analgesia compared with paravertebral blocks. Without a dramatic improvement in safety profile for serratus blocks, it appears that paravertebral blocks are superior to serratus blocks for postoperative analgesia after non-mastectomy breast surgery.Trial registration numberNCT03860974.

BACKGROUND We recently reported that a 6-day continuous peripheral nerve block reduced established postamputation phantom pain 3 weeks after treatment ended. However, the immediate effects of perineural infusion (secondary outcomes) have yet to be reported. METHODS Participants from 5 enrolling academic centers with an upper or lower limb amputation and established phantom pain received a single-injection ropivacaine peripheral nerve block(s) and perineural catheter insertion(s). They were subsequently randomized to receive a 6-day ambulatory perineural infusion of either ropivacaine 0.5% or normal saline in a double-masked fashion. Participants were contacted by telephone 1, 7, 14, 21, and 28 days after the infusion started, with pain measured using the Numeric Rating Scale. Treatment effects were assessed using the Wilcoxon rank-sum test at each time point. Adjusting for 4 time points (days 1, 7, 14, and 21), P < .0125 was deemed statistically significant. Significance at 28 days was reported using methods from the original, previously published article. RESULTS Pretreatment average phantom and residual pain scores were balanced between the groups. The day after infusion initiation (day 1), average phantom, and residual limb pain intensity was lower in patients receiving local anesthetic (n = 71) versus placebo (n = 73): median [quartiles] of 0 [0-2.5] vs 3.3 [0-5.0], median difference (98.75% confidence interval [CI]) of -1.0 (-3.0 to 0) for phantom pain (P = .001) and 0 [0-0] vs 0 [0-4.3], and median difference 0.0 (-2.0 to 0.0) for residual limb pain (P < .001). Pain's interference with physical and emotional functioning as measured with the interference domain of the Brief Pain Inventory improved during the infusion on day 1 for patients receiving local anesthetic versus placebo: 0 [0-10] vs 10 [0-40], median difference (98.75% CI) of 0.0 (-16.0 to 0.0), P = .002. Following infusion discontinuation (day 6), a few differences were found between the active and placebo treatment groups between days 7 and 21. In general, sample medians for average phantom and residual limb pain scores gradually increased after catheter removal for both treatments, but to a greater degree in the control group until day 28, at which time the differences between the groups returned to statistical significance. CONCLUSIONS This secondary analysis suggests that a continuous peripheral nerve block decreases phantom and residual limb pain during the infusion, although few improvements were again detected until day 28, 3 weeks following catheter removal.

We sought to develop a predictive model for discharge to post-acute care facilities in patients undergoing unilateral total hip replacement (THR). Furthermore, we sought to determine if the use of neuraxial anesthesia was an important covariate for the predictive model.Retrospective observational study.Preoperative care and operating room at a single institution.Patients (n = 960) who underwent an elective primary THR between 2014 and 2016.No intervention was performed.We collected variables that were known preoperatively including age, sex, body mass index (BMI), preoperative opioid use, functional status based on metabolic equivalents (METS), preoperative anemia, thrombocytopenia, osteoarthritis and contralateral osteoarthritis grade, anesthesia type, comorbidities and surgical approach. We then performed multivariable logistic regression to develop a predictive model.Female sex, preoperative opioid use, older age, general anesthesia, anemia, hypertension, a psychiatric diagnosis, use of dialysis, metabolic equivalents4 and obesity are all risk factors for a post-acute facility discharge. The use of general anesthesia compared to neuraxial anesthesia was associated with increased odds (odds ratio 1.98, 95% confidence interval 1.31-3.00, p = 0.001) for post-acute facility discharge. Model performance was assessed using ten-fold cross-validation - the average area under the receiver operating characteristic curve calculated was 0.794.We developed a predictive model for post-acute care facility discharge following THR. The use of neuraxial anesthesia was associated with decreased odds for post-acute care facility discharge.

Author(s): Gabriel, Rodney A; Finneran, John J; Swisher, Matthew W; Said, Engy T; Sztain, Jacklynn F; Khatibi, Bahareh; Wallace, Anne M; Hosseini, Ava; Trescot, Andrea M; Ilfeld, Brian M | Abstract: BackgroundAcute post-mastectomy pain is frequently challenging to adequately treat with local anesthetic-based regional anesthesia techniques due to its relatively long duration measured in multiple weeks.CaseWe report three cases in which preoperative ultrasound-guided percutaneous intercostal nerve cryoneurolysis was performed to treat pain following mastectomy. Across all postoperative days and all three patients, the mean pain score on the numeric rating scale was 0 for each day. Similarly, no patient required any supplemental opioid analgesics during the entire postoperative period; and, no patient reported insomnia or awakenings due to pain at any time point. This was a significant improvement over historic cohorts.ConclusionsUltrasound-guided percutaneous cryoanalgesia is a potential novel analgesic modality for acute pain management which has a duration that better-matches mastectomy than other currently-described techniques. Appropriately powered randomized, controlled clinical trials are required to demonstrate and quantify both potential benefits and risks.

Opioids are an indispensable component of perioperative pain management; however, the burgeoning opioid epidemic necessitates research into the risk factors for the development of opioid dependence and abuse following surgery. Diabetes has been identified as a risk factor for prolonged opioid utilisation following non-orthopaedic surgery; however, this association has not been investigated following orthopaedic surgery. To bridge this gap in the literature, we performed a retrospective propensity-matched cohort study in patients undergoing primary unilateral total hip arthroplasty. Propensity-matched cohorts were created to compare patients with and without preexisting diabetes mellitus. Outcomes of interest were opioid utilisation and subjective pain on postoperative day 1. Our results did not identify an association between preexisting diabetes and postoperative pain or opioid utilisation. While this study did not identify an association between diabetes and opioid utilisation following total hip arthroplasty, future studies should pursue a prospective, longitudinal approach and investigate other common orthopaedic procedures.

BACKGROUND:A continuous adductor canal block provides analgesia after surgical procedures of the knee. Recent neuroanatomic descriptions of the thigh and knee led us to speculate that local anesthetic deposited in the distal thigh close to the adductor hiatus would provide superior analgesia compared to a more proximal catheter location. We therefore tested the hypothesis that during a continuous adductor canal nerve block, postoperative analgesia would be improved by placing the perineural catheter tip 2-3 cm cephalad to where the femoral artery descends posteriorly to the adductor hiatus (distal location) compared to a more proximal location at the midpoint between the anterior superior iliac spine and the superior border of the patella (proximal location). METHODS:Preoperatively, subjects undergoing total knee arthroplasty received an ultrasound-guided perineural catheter inserted either in the proximal or distal location within the adductor canal in a randomized, subject-masked fashion. Subjects received a single injection of lidocaine 2% via the catheter preoperatively, followed by an infusion of ropivacaine 0.2% (8 mL/h basal, 4 mL bolus, 30 minutes lockout) for the study duration. After joint closure, the surgeon infiltrated the entire joint using 30 mL of ropivacaine (0.5%), ketorolac (30 mg), epinephrine (5 μg/mL), and tranexamic acid (2 g). The primary end point was the median level of pain as measured on a numeric rating scale (NRS) during the time period of 8:00 AM to 12:00 PM the day after surgery. RESULTS:For the primary end point, the NRS of subjects with a catheter inserted at the proximal location (n = 24) was a median (10th, 25th-75th, 90th quartiles) of 0.5 (0.0, 0.0-3.2, 5.0) vs 3.0 (0.0, 2.0-5.4, 7.8) for subjects with a catheter inserted in the distal location (n = 26; P = .011). Median and maximum NRSs were lower in the proximal group at all other time points, but these differences did not reach statistical significance. There were no clinically relevant or statistically significant differences between the treatment groups for any other secondary end point, including opioid consumption and ambulation distance. CONCLUSIONS:For continuous adductor canal blocks accompanied by intraoperative periarticular local anesthetic infiltration, analgesia the day after knee arthroplasty is improved with a catheter inserted at the level of the midpoint between the anterior superior iliac spine and the superior border of the patella compared with a more distal insertion closer to the adductor hiatus.

We present the case of a 55-year-old woman undergoing a delayed latissimus dorsi flap breast reconstruction after a simple mastectomy for breast cancer. Preoperatively, 2 unilateral paravertebral catheters were placed at T3/4 and T7/8 for postoperative analgesia. Postoperatively, ropivacaine 0.2% was infused until the day of discharge on postoperative day 2. The patient had excellent postoperative analgesia and required no opioids or other analgesics through postoperative day 10. We report that multilevel paravertebral nerve blockade could represent an opioid-sparing alternative for postoperative analgesia for latissimus dorsi flap breast reconstruction patients.

We tested the hypothesis that during a continuous popliteal-sciatic nerve block, postoperative analgesia is improved with the catheter insertion point "deep" to the paraneural sheath immediately distal to the bifurcation between the tibial and common peroneal branches, compared with the traditional approach "superficial" to the paraneural sheath proximal to the bifurcation. The needle tip location was determined to be accurately located with a fluid bolus visualized with ultrasound; however, catheters were subsequently inserted without a similar fluid injection and visualization protocol (visualized air injection was permitted and usually implemented, but not required per protocol). The average pain (0-10 scale) the morning after surgery for subjects with a catheter inserted at the proximal subparaneural location (n = 31) was a median (interquartile) of 1.5 (0.0-3.5) vs 1.5 (0.0-4.0) for subjects with a catheter inserted at the distal supraparaneural location (n = 32; P = .927). Secondary outcomes were similarly negative.

Background and Objectives Percutaneous peripheral nerve stimulation (PNS) is an analgesic modality involving the insertion of a lead through an introducing needle followed by the delivery of electric current. This modality has been reported to treat chronic pain as well as postoperative pain the day following knee surgery. However, it remains unknown if this analgesic technique may be used in ambulatory subjects following foot procedures beginning within the recovery room immediately following surgery, and with only short series of patients reported to date, the only available data are derived from strictly observational studies. The purposes of this proof-of-concept study were to demonstrate the feasibility of using percutaneous sciatic nerve PNS to treat postoperative pain following ambulatory foot surgery in the immediate postoperative period and provide the first available data from a randomized controlled study design to provide evidence of analgesic effect. Methods Preoperatively, an electrical lead (SPRINT; SPR Therapeutics, Inc, Cleveland, Ohio) was percutaneously inserted posterior to the sciatic nerve between the subgluteal region and bifurcation with ultrasound guidance. Following hallux valgus osteotomy, subjects received 5 minutes of either stimulation or sham in a randomized, double-masked fashion followed by a 5-minute crossover period and then continuous stimulation until lead removal on postoperative days 14 to 28. Results During the initial 5-minute treatment period, subjects randomized to stimulation (n = 4) experienced a downward trajectory in their pain over the 5 minutes of treatment, whereas those receiving sham (n = 3) reported no such change until their subsequent 5-minute stimulation crossover. During the subsequent 30 minutes of stimulation, pain scores decreased to 52% of baseline (n = 7). Three subjects (43%) used a continuous popliteal nerve block for rescue analgesia during postoperative days 0 to 3. Overall, resting and dynamic pain scores averaged less than 1 on the numeric rating scale, and opioid use averaged less than 1 tablet daily with active stimulation. One lead dislodged, 2 fractured during use, and 1 fractured during intentional withdrawal. Conclusions This proof-of-concept study demonstrates that percutaneous sciatic nerve PNS is feasible for ambulatory foot surgery and suggests that this modality provides analgesia and decreases opioid requirements following hallux valgus procedures. However, lead dislodgement and fracture are concerns. Clinical Trial Registration This study was registered at Clinicaltrials.gov, identifier NCT02898103.

Author(s): Ilfeld, Brian M; Said, Engy T; Finneran, John J; Sztain, Jacklynn F; Abramson, Wendy B; Gabriel, Rodney A; Khatibi, Bahareh; Swisher, Matthew W; Jaeger, Pia; Covey, Dana C; Robertson, Catherine M | Abstract: ObjectivesThe purpose of this prospective proof of concept study was to investigate the feasibility of using percutaneous peripheral nerve stimulation of the femoral nerve to treat pain in the immediate postoperative period following ambulatory anterior cruciate ligament reconstruction with a patellar autograft.Materials and methodsPreoperatively, an electrical lead (SPRINT, SPR Therapeutics, Inc., Cleveland, OH, USA) was percutaneously implanted with ultrasound guidance anterior to the femoral nerve caudad to the inguinal crease. Within the recovery room, subjects received 5 min of either stimulation or sham in a randomized, double-masked fashion followed by a 5-min crossover period, and then continuous active stimulation until lead removal postoperative Day 14-28. Statistics were not applied to the data due to the small sample size of this feasibility study.ResultsDuring the initial 5-min treatment period, subjects randomized to stimulation (n = 5) experienced a slight downward trajectory (decrease of 7%) in their pain over the 5 min of treatment, while those receiving sham (n = 5) reported a slight upward trajectory (increase of 4%) until their subsequent 5-min stimulation crossover, during which time they also experienced a slight downward trajectory (decrease of 11% from baseline). A majority of subjects (80%) used a continuous adductor canal nerve block for rescue analgesia (in addition to stimulation) during postoperative Days 1-3, after which the median resting and dynamic pain scores remained equal or less than 1.5 on the numeric rating scale, respectively, and the median daily opioid consumption was less than 1.0 tablet.ConclusionsThis proof of concept study demonstrates that percutaneous femoral nerve stimulation is feasible for ambulatory knee surgery; and suggests that this modality may be effective in providing analgesia and decreasing opioid requirements following anterior cruciate ligament reconstruction. clinicaltrials.gov: NCT02898103.

Author(s): Ilfeld, Brian M; Ball, Scott T; Gabriel, Rodney A; Sztain, Jacklynn F; Monahan, Amanda M; Abramson, Wendy B; Khatibi, Bahareh; Said, Engy T; Parekh, Jesal; Grant, Stuart A; Wongsarnpigoon, Amorn; Boggs, Joseph W | Abstract: IntroductionThe objective of the present feasibility study was to investigate the use of a new treatment modality-percutaneous peripheral nerve stimulation (PNS)-in controlling the often severe and long-lasting pain following total knee arthroplasty (TKA).MethodsFor patients undergoing a primary, unilateral TKA, both femoral and sciatic open-coil percutaneous leads (SPR Therapeutics, Cleveland, OH) were placed up to seven days prior to surgery using ultrasound guidance. The leads were connected to external stimulators and used both at home and in the hospital for up to six weeks total.ResultsIn six of seven subjects (86%), the average of daily pain scores across the first two weeks was l4 on the 0-10 Numeric Rating Scale for pain. A majority of subjects (four out of seven; 57%) had ceased opioid use within the first week (median time to opioid cessation for all subjects was six days). Gross sensory/motor function was maintained during stimulation, enabling stimulation during physical therapy and activities of daily living. At 12 weeks following surgery, six of seven subjects had improved by g10% on the Six-Minute Walk Test compared to preoperative levels, and WOMAC scores improved by an average of 85% compared to before surgery. No falls, motor block, or lead infections were reported.ConclusionsThis feasibility study suggests that for TKA, ultrasound-guided percutaneous PNS is feasible in the immediate perioperative period and may provide analgesia without the undesirable systemic effects of opioids or quadriceps weakness induced by local anesthetics-based peripheral nerve blocks.

Continuous Popliteal Sciatic Blocks: Does Varying Perineural Catheter Location Relative to the Sciatic Bifurcation Influence Block Effects? A Dual-Center, Randomized, Subject-Masked, Controlled Clinical Trial Amanda M. Monahan, MD,* Sarah J. Madison, MD,* Vanessa J. Loland, MD,* Jacklynn F. Sztain, MD,* Michael L. Bishop, MD,* NavParkash S. Sandhu, MD,* Richard H. Bellars, MD,* Bahareh Khatibi, MD,* Alexandra K. Schwartz, MD,† Sonya S. Ahmed, MD,† Michael C. Donohue, PhD,‡ Scott T. Nomura, BS,§ Cindy H. Wen, BS,‖ and Brian M. Ilfeld, MD, MS*¶ BACKGROUND: Multiple studies have demonstrated that, for single-injection popliteal sciatic nerve blocks, block characteristics are dependent upon local anesthetic injection relative to the sciatic nerve bifurcation. In contrast, this relation remains unexamined for continuous pop- liteal sciatic nerve blocks. We, therefore, tested the hypothesis that postoperative analgesia is improved with the perineural catheter tip at the level of the bifurcation compared with 5 cm proximal to the bifurcation. METHODS: Preoperatively, subjects having moderately painful foot or ankle surgery were randomly assigned to receive an ultrasound-guided subepimyseal perineural catheter inserted either at or 5 cm proximal to the sciatic nerve bifurcation. Subjects received a single injection of mepivacaine 1.5% either via the insertion needle preoperatively or the perineural catheter postoperatively, fol- lowed by an infusion of ropivacaine 0.2% (6 mL/h basal, 4 mL bolus, and 30-min lockout) for the study duration. The primary end point was the average pain measured on a numeric rating scale (0–10) in the 3 hours before a data collection telephone call the morning after surgery. RESULTS: The average numeric rating scale of subjects with a catheter inserted at the sciatic nerve bifurcation (n = 64) was a median (10th, 25th to 75th, and 90th quartiles) of 3.0 (0.0, 2.4–5.0, and 7.0) vs 2.0 (0.0, 1.0–4.0, and 5.0) for subjects with a catheter inserted proximal to the bifurcation (n = 64; P = 0.008). Similarly, maximum pain scores were greater in the group at the bifurcation: 6.0 (3.0, 4.4–8.0, and 9.0) vs 5.0 (0.0, 3.0–8.0, and 10.0) (P = 0.019). Differences between the groups for catheter insertion time, opioid rescue dose, degree of numbness in the foot/toes, catheter dislodgement, and fluid leakage did not reach statistical significance. CONCLUSIONS: For continuous popliteal sciatic nerve blocks, a catheter inserted 5 cm proximal to the sciatic nerve bifurcation provides superior postoperative analgesia in subjects having moderately painful foot or ankle surgery compared with catheters located at the bifurcation. This is in marked contrast with single-injection popliteal sciatic nerve blocks for which benefits are afforded to local anesthetic injection distal, rather than proximal, to the bifurcation. (Anesth Analg 2016;122:1689–95) C ontinuous popliteal sciatic nerve blocks provide postoperative analgesia after surgical procedures of the foot and ankle. 1 The sciatic nerve courses down From the *Department of Anesthesiology, University of California San Diego, San Diego, California; †Department of Orthopedics, University of California San Diego, San Diego, California; ‡Division of Biostatistics and Bioinformat- ics, University of California San Diego, San Diego, ­California; §School of Med- icine, University of California San Diego, San Diego, C ­ alifornia; ‖Department of Ophthalmology, University of California San Diego, San Diego, California; and ¶Outcomes Research Consortium, Cleveland, Ohio. Accepted for publication December 28, 2015. Funding: Funding for this project was provided by the National Institutes of Health grant GM077026 (Principal Investigator: Dr. Ilfeld) from the National Institute of General Medical Sciences (Bethesda, Maryland); and the Department of Anesthesiology, University California San Diego (San Diego, California). The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the funding entities. The authors declare no conflicts of interest. Reprints will not be available from the authors. Address correspondence to Brian M. Ilfeld, MD, MS, Department of ­Anesthesiology, University of California San Diego, 200 West Arbor Dr., MC 8770, San Diego, CA 92103. Address e-mail to bilfeld@ucsd.edu. Copyright © 2016 International Anesthesia Research Society DOI: 10.1213/ANE.0000000000001211 May 2016 • Volume 122 • Number 5 the posterior thigh and bifurcates just above or within the popliteal fossa into 2 branches: the tibial and common peroneal nerves. Cadaver studies have confirmed the location of this bifurcation to range from approximately 0 to 11 cm proximal to popliteal crease, most commonly 5 to 7 cm above the crease. 2,3 Using ultrasound guidance, practitioners can target a precise location along the sciatic nerve relative to the sciatic bifurcation for deposition of local anesthetic. 4–6 Previous randomized studies document that depositing an initial bolus of local anesthetic via a needle distal to the sciatic bifurcation—compared with proximal to the bifur- cation—results in decreased time to onset of sensory and motor block and at times an increased surgical-quality block success rate. 4–6 This suggests that deposition of local anes- thetic at various locations along the sciatic nerve can influ- ence block characteristics. However, findings from studies involving single-injection nerve blocks have not always been replicated when investigated in relation to continuous peripheral nerve blocks. 7–12 Whether the perineural catheter location relative to the sciatic nerve bifurcation influences www.anesthesia-analgesia.org 1689 Copyright © 2016 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.

BackgroundIt remains unknown whether continuous or scheduled intermittent bolus local anesthetic administration is preferable for adductor canal perineural catheters. Therefore, we tested the hypothesis that scheduled bolus administration is superior or noninferior to a continuous infusion on cutaneous knee sensation in volunteers.MethodsBilateral adductor canal catheters were inserted in 24 volunteers followed by ropivacaine 0.2% administration for 8 hours. One limb of each subject was assigned randomly to a continuous infusion (8 mL/h) or automated hourly boluses (8 mL/bolus), with the alternate treatment in the contralateral limb. The primary end point was the tolerance to electrical current applied through cutaneous electrodes in the distribution of the anterior branch of the medial femoral cutaneous nerve after 8 hours (noninferiority delta: -10 mA). Secondary end points included tolerance of electrical current and quadriceps femoris maximum voluntary isometric contraction strength at baseline, hourly for 14 hours, and again after 22 hours.ResultsThe 2 administration techniques provided equivalent cutaneous analgesia at 8 hours because noninferiority was found in both directions, with estimated difference on tolerance to cutaneous current of -0.6 mA (95% confidence interval, -5.4 to 4.3). Equivalence also was found on all but 2 secondary time points.ConclusionsNo evidence was found to support the hypothesis that changing the local anesthetic administration technique (continuous basal versus hourly bolus) when using an adductor canal perineural catheter at 8 mL/h decreases cutaneous sensation in the distribution of the anterior branch of the medial femoral cutaneous nerve.

We describe a novel technique of real-time ultrasound-guided superior laryngeal nerve and translaryngeal blocks in 4 patients with anticipated difficult airways. All patients had altered neck anatomy, and 1 had a prior unsuccessful awake fiberoptic bronchoscopic intubation. For block performance, an 11-mm broadband curved array transducer with a scanning frequency between 8 and 5 MHz (Sonosite, Bothell, WA) was used for anatomical structure identification, needle guidance toward each superior laryngeal nerve and through the cricothyroid membrane, and deposition of local anesthetic in the appropriate location. This was followed by successful awake fiberoptic bronchoscopic endotracheal intubation in all cases.

Copyright © 2015, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. Background: The authors conducted a randomized, controlled, parallel-arm, superiority study to test the hypothesis that a continuous adductor canal block decreases the time to attain four discharge criteria compared with a continuous femoral nerve block after tricompartment knee arthroplasty. Methods: Subjects undergoing tricompartment knee arthroplasty were randomized using computer-generated lists to either an adductor canal or femoral perineural catheter (3-day ropivacaine 0.2% infusion) in an unmasked manner. The primary outcome was the time to attain four criteria: (1) adequate analgesia; (2) intravenous opioids independence; (3) ability to stand, walk 3 m, return, and sit down; and (4) ambulate 30 m. Results: Subjects with an adductor canal catheter (n = 39) reached all four criteria in a median of 55 h (interquartile, 42 to 63 h) compared with 61 h (49 to 69 h) for those with a femoral catheter (n = 41; 95% CI, -13 to 1 h; P = 0.12). The percentage of subjects who reached the two mobilization criteria on postoperative days 1 and 2 were 72 and 95% for those with an adductor canal catheter (n = 39), but only 27 and 76% in subjects with a femoral catheter (n = 41; both P < 0.001). Differences in pain scores at rest and intravenous opioid requirements were minimal, but femoral infusion improved dynamic analgesia (P = 0.01 to 0.02). Conclusion: Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the time to overall discharge readiness even though it did decrease the time until adequate mobilization, primarily because both groups experienced similar analgesia and intravenous opioid requirements that-in most cases-exceeded the time to mobilization.

The authors conducted a randomized, controlled, parallel-arm, superiority study to test the hypothesis that a continuous adductor canal block decreases the time to attain four discharge criteria compared with a continuous femoral nerve block after tricompartment knee arthroplasty.Subjects undergoing tricompartment knee arthroplasty were randomized using computer-generated lists to either an adductor canal or femoral perineural catheter (3-day ropivacaine 0.2% infusion) in an unmasked manner. The primary outcome was the time to attain four criteria: (1) adequate analgesia; (2) intravenous opioids independence; (3) ability to stand, walk 3 m, return, and sit down; and (4) ambulate 30 m.Subjects with an adductor canal catheter (n = 39) reached all four criteria in a median of 55 h (interquartile, 42 to 63 h) compared with 61 h (49 to 69 h) for those with a femoral catheter (n = 41; 95% CI, -13 to 1 h; P = 0.12). The percentage of subjects who reached the two mobilization criteria on postoperative days 1 and 2 were 72 and 95% for those with an adductor canal catheter (n = 39), but only 27 and 76% in subjects with a femoral catheter (n = 41; both P0.001). Differences in pain scores at rest and intravenous opioid requirements were minimal, but femoral infusion improved dynamic analgesia (P = 0.01 to 0.02).Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the time to overall discharge readiness even though it did decrease the time until adequate mobilization, primarily because both groups experienced similar analgesia and intravenous opioid requirements that--in most cases--exceeded the time to mobilization.

© 2015 American Society of Regional Anesthesia and Pain Medicine. Background We tested the hypothesis that, following unicompartment knee arthroplasty, a continuous adductor canal block decreases the time to reach 4 discharge criteria compared with a continuous femoral nerve block. Methods Subjects were randomized to either an adductor canal or femoral perineural catheter (2-day ropivacaine 0.2% infusion) in an unmasked fashion. The primary outcome was the time to attain 4 discharge criteria: (1) adequate analgesia; (2) intravenous opioid independence; (3) ability to independently stand, walk 3 m, return, and sit down; and (4) ambulate 30 m. Results Subjects with an adductor canal catheter (n = 15) reached all 4 criteria in a median of 35 hours (interquartile range, 24-43 hours), compared with 40 hours (interquartile range, 27-69 hours) for those with a femoral catheter (n = 15; Wilcoxon rank sum test: P = 0.46; log-rank test: P = 0.16). However, the percentages of subjects (adductor canal: femoral) who reached the 2 mobilization criteria were 27%:0% on postoperative day (POD) 0, 93%:53% on POD 1, and 100%:73% on POD 2. Of adductor canal subjects, 100% were discharge ready by POD 2, compared with only 73% of femoral subjects (P < 0.001). Conclusions Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the median number of hours to overall discharge readiness, yet did decrease the number of discrete days until discharge readiness. These results are applicable to only unicompartment knee arthroplasty and must be considered preliminary because of the limited sample size of this pilot study.

Extraaxillary metastases (i.e., in the absence of axillary involvement) are more likely to develop in patients with inner-quadrant (IQ) breast cancer than in patients with outer-quadrant (OQ) primary tumors. The relative difficulty of identifying extraaxillary metastases may lead to understaging of cancer in these patients. This study examined whether (18)F-FDG PET findings were differentially associated with the location of primary tumors, and with long-term prognosis, in IQ and OQ patients.Follow-up data were obtained for 141 patients whose breast cancer was staged by PET and who were documented to have IQ (n = 42) or OQ (n = 99) primaries. Results were stratified according to PET findings consistent with different metastatic patterns. Data were further analyzed with respect to disease outcome after a mean 3-y follow-up period.Among IQ patients, progressive disease was identified in 26.1%, compared with 13.1% of OQ patients, for a relative risk (RR) of 2.0. Of patients with PET findings of isolated extraaxillary metastases, 36.1% had progressive disease, compared with 10.7% of other patients (RR = 3.4), and 61.9% of IQ patients had isolated extraaxillary metastases identified on PET, compared with 10.1% of OQ patients (RR = 6.1).IQ patients demonstrated a 6-fold greater frequency of PET findings of isolated extraaxillary metastasis, and such findings were associated with triple the risk for disease progression. Patients with IQ tumors could be vulnerable to understaging with conventional staging approaches and may particularly benefit from PET during the staging process.