Simulation-based ultrasound-guided regional anesthesia education: a national survey of Canadian anesthesiology residency training programs.

PURPOSE: Simulation-based education in ultrasound-guided regional anesthesia (UGRA) improves knowledge, skills, and patient outcomes. Nevertheless, it is not known how simulation-based UGRA education is used across Canada. We aimed to characterize the current use of simulation-based UGRA education in Canadian anesthesiology residency training programs. METHODS: We developed and distributed a structured national survey to simulation leads of all 17 Canadian anesthesiology residency training programs. The survey inquired about program demographics, simulation modalities, facilitators and barriers to simulation use, use for assessment, and beliefs around simulation-based UGRA education. We gathered data from August to November 2023 and summarized our findings descriptively. RESULTS: Fifteen programs (88%) responded to our survey. Eight programs (53%) used UGRA simulation for technical training and nine programs (60%) for nontechnical training. The most common simulators used were live model scanning (13 programs, 87%) and gel phantom models (7 programs, 47%). Five programs (33%) mandated simulation-based UGRA in their curriculum. We found that deliberate practice and improved patient safety were most valued in simulation training while lack of funding and faculty availability were the most common barriers to implementation. Most respondents agreed that formative simulation-based education would improve trainee skills and called for greater standardization. Nevertheless, there were mixed responses regarding summative UGRA simulation and the need for simulation proficiency before clinical practice. CONCLUSIONS: Our findings show significant variations in simulation implementation and views on UGRA simulation-based education among Canadian anesthesiology residency training programs. Future studies should explore avenues to overcome barriers and improve knowledge translation in UGRA.

RéSUMé: OBJECTIF: La formation basée sur la simulation en anesthésie régionale échoguidée améliore les connaissances, les compétences et les issues pour les patient·es. Néanmoins, on ne sait pas comment la formation en AR échoguidée basée sur la simulation est utilisée au Canada. Nous avons cherché à caractériser l'utilisation actuelle de l'enseignement de l'AR échoguidée basée sur la simulation dans les programmes canadiens de résidence en anesthésiologie. MéTHODE: Nous avons élaboré et distribué un sondage national structuré aux responsables de la simulation des 17 programmes canadiens de résidence en anesthésiologie. L'enquête portait sur les données démographiques du programme, les modalités de simulation, les facilitateurs et les obstacles à l'utilisation de la simulation, son utilisation pour l'évaluation, et les croyances concernant l'éducation en AR échoguidée basée sur la simulation. Nous avons recueilli des données d'août à novembre 2023 et résumé nos résultats de manière descriptive. RéSULTATS: Quinze programmes (88 %) ont répondu à notre sondage. Huit programmes (53 %) utilisent la simulation en AR échoguidée pour la formation technique et neuf programmes (60 %) pour la formation non technique. Les simulateurs les plus couramment utilisés étaient le balayage sur modèles vivants (13 programmes, 87 %) et les modèles de fantômes en gel (7 programmes, 47 %). Cinq programmes (33 %) ont rendu obligatoire l'AR échoguidée basée sur la simulation dans leur programme. Nous avons constaté que la pratique délibérée et l'amélioration de la sécurité des patient·es étaient les plus appréciées dans la formation par simulation, tandis que le manque de financement et la disponibilité du corps professoral étaient les obstacles les plus courants à la mise en œuvre. La plupart des répondant·es ont convenu que l'éducation formative basée sur la simulation améliorerait les compétences des stagiaires et ont appelé à une plus grande standardisation. Néanmoins, les réponses étaient mitigées concernant la simulation sommative en AR échoguidée et la nécessité d'une maîtrise de la simulation avant la pratique clinique. CONCLUSION: Nos résultats montrent des variations significatives dans la mise en œuvre de la simulation et les points de vue sur l'éducation basée sur la simulation en AR échoguidée parmi les programmes canadiens de résidence en anesthésiologie. Les études futures devraient explorer les moyens de surmonter les obstacles et d'améliorer l'application des connaissances à l'anesthésie régionale échoguidée.

A quasi-experimental evaluation of the association between implementation of Quality-Based Procedures funding for hip fractures and improvements in processes and outcomes for hip fracture patients in Ontario: an interrupted time series analysis.

PURPOSE: In 2013, Ontario introduced a patient-based funding model for hip fracture care (Quality-Based Procedures [QBP]). The association of QBP implementation with changes in processes and outcomes has not been evaluated. METHODS: We conducted a quasi-experimental study using linked health data for adult hip fractures as an interrupted time series. The pre-QBP period was from 2008 to 2012 and the post-QBP period was from 2014 to 2018; 2013 was excluded as a wash-in period. We used segmented regression analyses to estimate the association of QBP implementation with changes in processes (surgery in less than two days from admission, use of echocardiography, use of nerve blocks, and provision of geriatric care) and clinical outcomes (90-day mortality, 90-day readmissions, length of stay, and days alive at home). We estimated the immediate (level) change, trend (slope) postimplementation, and total counterfactual differences. Sensitivity analyses included case-mix adjustment and stratification by hospital type and procedure. RESULTS: We identified 45,500 patients in the pre-QBP period and 41,256 patients in the post-QBP period. There was a significant total counterfactual increase in the use of nerve blocks (11.1%; 95% confidence interval [CI], 6.2 to 16.0) and a decrease in the use of echocardiography (-2.5%; 95% CI, -3.7 to -1.3) after QBP implementation. The implementation of QBP was not associated with a clinically or statistically meaningful change in 90-day mortality, 90-day readmission, length of stay, or number of days alive at home. CONCLUSION: Evaluation of the QBP program is crucial to inform ongoing and future changes to policy and funding for hip fracture care. The introduction of the QBP Hip Fracture program, supported by evidence-based recommendations, was associated with improved application of some evidence-based processes of care but no changes in clinical outcomes. There is a need for ongoing development and evaluation of funding models to identify optimal strategies to improve the value and outcomes of hip fracture care. STUDY REGISTRATION: Open Science Framework ( https://osf.io/2938h/ ); first posted 13 June 2022.

RéSUMé: OBJECTIF: En 2013, l'Ontario a mis en place un modèle de financement axé sur les patient·es pour les soins suivant une fracture de la hanche (procédures fondées sur la qualité [PFQ]). L'association entre la mise en œuvre des PFQ et les changements dans les processus et les devenirs n'a pas été évaluée. MéTHODE: Nous avons mené une étude quasi expérimentale en utilisant des données de santé couplées pour les fractures de la hanche chez l'adulte comme une série chronologique interrompue. La période précédant les PFQ s'étendait de 2008 à 2012, et la période subséquente à l'implantation des PFQ allait de 2014 à 2018. L'année 2013 a été exclue en tant que période de rodage. Nous avons utilisé des analyses de régression segmentées pour estimer l'association entre la mise en œuvre des PFQ avec des changements aux processus (chirurgie en moins que deux jours suivant l'admission, utilisation de l'échocardiographie, utilisation de blocs nerveux et prestation de soins gériatriques) et des issues cliniques (mortalité à 90 jours, réadmissions à 90 jours, durée de séjour et jours de vie à domicile). Nous avons estimé le changement immédiat (niveau), la tendance (pente) après la mise en œuvre et les différences contrefactuelles totales. Les analyses de sensibilité comprenaient l'ajustement et la stratification de la combinaison de cas par type d'hôpital et par procédure. RéSULTATS: Nous avons identifié 45 500 patient·es dans la période pré-PFQ et 41 256 patient·es dans la période post-PFQ. Il y a eu une augmentation contrefactuelle totale significative de l'utilisation de blocs nerveux (11,1 %; intervalle de confiance [IC] à 95 %, 6,2 à 16,0) et une diminution de l'utilisation de l'échocardiographie (−2,5 %; IC 95 %, −3,7 à −1,3) après la mise en œuvre des PFQ. La mise en œuvre des PFQ n'a pas été associée à un changement cliniquement ou statistiquement significatif de la mortalité à 90 jours, de la réadmission à 90 jours, de la durée de séjour ou du nombre de jours de vie à domicile. CONCLUSION: L'évaluation du programme de PFQ est cruciale pour guider les changements actuels et futurs aux politiques et au financement des soins suivant une fracture de la hanche. La mise en place du programme de PFQ pour les fractures de la hanche, appuyée par des recommandations fondées sur des données probantes, a été associée à une meilleure application de certains processus de soins fondés sur des données probantes, mais à aucun changement dans les devenirs cliniques. Il est nécessaire d'élaborer et d'évaluer continuellement des modèles de financement afin de déterminer les stratégies optimales pour améliorer la valeur et les devenirs des soins suivant une fracture de la hanche. ENREGISTREMENT DE L'éTUDE: Open Science Framework ( https://osf.io/2938h/ ); première publication le 13 juin 2022.

Hospital-, anaesthetist-, and patient-level variation in peripheral nerve block utilisation for hip fracture surgery: a population-based cross-sectional study.

BACKGROUND: Unwarranted variation in anaesthesia practice is associated with adverse outcomes. Despite high-certainty evidence of benefit, a minority of hip fracture surgery patients receive a peripheral nerve block. Our objective was to estimate variation in peripheral nerve block use at the hospital, anaesthetist, and patient levels, while identifying predictors of peripheral nerve block use in hip fracture patients. METHODS: After protocol registration (https://osf.io/48bvp/), we conducted a population-based cross-sectional study using linked administrative data in Ontario, Canada. We included adults >65 yr of age having emergency hip fracture surgery from April 1, 2012 to March 31, 2018. Logistic mixed models were used to estimate the variation in peripheral nerve block use attributable to hospital-, anaesthetist-, and patient-level factors with use of peripheral nerve block, quantified using the variance partition coefficient and median odds ratio. Predictors of peripheral nerve block use were estimated and temporally validated. RESULTS: Of 50 950 patients, 9144 (18.5%) received a peripheral nerve block within 1 day of surgery. Patient-level factors accounted for 14% of variation, whereas 42% and 44% were attributable to the hospital and anaesthetist providing care, respectively. The median odds ratio for receiving a peripheral nerve block was 5.73 at the hospital level and 5.97 at the anaesthetist level. No patient factors had large associations with receipt of a peripheral nerve block (odds ratios significant at the 5% level ranged from 0.86 to 1.35). CONCLUSIONS: Patient factors explain the minimal variation in peripheral nerve block use for hip fracture surgery. Interventions to increase uptake of peripheral nerve blocks for hip fracture patients will likely need to focus on structures and processes at the hospital and anaesthetist levels.

Persistent Postoperative Opioid Prescription Fulfillment and Peripheral Nerve Blocks for Ambulatory Shoulder Surgery: A Retrospective Cohort Study.

BACKGROUND: There is need to identify perioperative interventions that decrease chronic opioid use. The authors hypothesized that receipt of a peripheral nerve block would be associated with a lower incidence of persistent postoperative opioid prescription fulfillment. METHODS: This was a retrospective population-based cohort study examining ambulatory shoulder surgery patients in Ontario, Canada. The main outcome measure was persistent postoperative opioid prescription fulfillment. In opioid-naive patients (no opioid prescription fulfillment in 90 days preoperatively), this was present if an individual fulfilled an opioid prescription of at least a 60-day supply during postoperative days 90 to 365. In opioid-exposed (less than 60 mg oral morphine equivalent dose per day within 90 days preoperatively) or opioid-tolerant (60 mg oral morphine equivalent dose per day or above within 90 days preoperatively) patients, this was classified as present if an individual experienced any increase in opioid prescription fulfillment from postoperative day 90 to 365 relative to their baseline use before surgery. The authors' exposure was the receipt of a peripheral nerve block. RESULTS: The authors identified 48,523 people who underwent elective shoulder surgery from July 1, 2012, to December 31, 2017, at one of 118 Ontario hospitals. There were 8,229 (17%) patients who had persistent postoperative opioid prescription fulfillment. Of those who received a peripheral nerve block, 5,008 (16%) went on to persistent postoperative opioid prescription fulfillment compared to 3,221 (18%) patients who did not (adjusted odds ratio, 0.90; 95% CI, 0.83 to 0.97; P = 0.007). This statistically significant observation was not reproduced in a coarsened exact matching sensitivity analysis (adjusted odds ratio, 0.85; 95% CI, 0.71 to 1.02; P = 0.087) or several other subgroup and sensitivity analyses. CONCLUSIONS: This retrospective analysis found no association between receipt of a peripheral nerve block and a lower incidence of persistent postoperative opioid prescription fulfillment in ambulatory shoulder surgery patients.

Peripheral Nerve Blocks and Potentially Attributable Adverse Events in Older People with Hip Fracture: A Retrospective Population-based Cohort Study.

BACKGROUND: Peripheral nerve blocks are being used with increasing frequency for management of hip fracture-related pain. Despite converging evidence that nerve blocks may be beneficial, safety data are lacking. This study hypothesized that peripheral nerve block receipt would not be associated with adverse events potentially attributable to nerve blocks, as well as overall patient safety incidents while in hospital. METHODS: This was a preregistered, retrospective population-based cohort study using linked administrative data. This study identified all hip fracture admissions in people 50 yr of age or older and identified all nerve blocks (although we were unable to ascertain the specific anatomic location or type of block), potentially attributable adverse events (composite of seizures, fall-related injuries, cardiac arrest, nerve injury), and any patient safety events using validated codes. The study also estimated the unadjusted and adjusted association of nerve blocks with adverse events; adjusted absolute risk differences were also calculated. RESULTS: In total, 91,563 hip fracture patients from 2009 to 2017 were identified; 15,631 (17.1%) received a nerve block, and 5,321 (5.8%; 95% CI, 5.7 to 6.0%) patients experienced a potentially nerve block-attributable adverse event: 866 (5.5%) in patients with a block and 4,455 (5.9%) without a block. Before and after adjustment, nerve blocks were not associated with potentially attributable adverse events (adjusted odds ratio, 1.05; 95% CI, 0.97 to 1.15; and adjusted risk difference, 0.3%, 95% CI, -0.1 to 0.8). CONCLUSIONS: The data suggest that nerve blocks in hip fracture patients are not associated with higher rates of potentially nerve block-attributable adverse events, although these findings may be influenced by limitations in routinely collected administrative data.

Non-Fellowship regional anesthesia training and assessment: an international Delphi study on a consensus curriculum.

BACKGROUND AND OBJECTIVES: While there are several published recommendations and guidelines for trainees undertaking subspecialty Fellowships in regional anesthesia, a similar document describing a core regional anesthesia curriculum for non-fellowship trainees is less well defined. We aimed to produce an international consensus for the training and teaching of regional anesthesia that is applicable for the majority of worldwide anesthesiologists. METHODS: This anonymous, electronic Delphi study was conducted over two rounds and distributed to current and immediate past (within 5 years) directors of regional anesthesia training worldwide. The steering committee formulated an initial list of items covering nerve block techniques, learning objectives and skills assessment and volume of practice, relevant to a non-fellowship regional anesthesia curriculum. Participants scored these items in order of importance using a 10-point Likert scale, with free-text feedback. Strong consensus items were defined as highest importance (score ≥8) by ≥70% of all participants. RESULTS: 469 participants/586 invitations (80.0% response) scored in round 1, and 402/469 participants (85.7% response) scored in round 2. Participants represented 66 countries. Strong consensus was reached for 8 core peripheral and neuraxial blocks and 17 items describing learning objectives and skills assessment. Volume of practice for peripheral blocks was uniformly 16-20 blocks per anatomical region, while ≥50 neuraxial blocks were considered minimum. CONCLUSIONS: This international consensus study provides specific information for designing a non-fellowship regional anesthesia curriculum. Implementation of a standardized curriculum has benefits for patient care through improving quality of training and quality of nerve blocks.

A Population-based Comparative Effectiveness Study of Peripheral Nerve Blocks for Hip Fracture Surgery.

BACKGROUND: Adverse outcomes and resource use rates are high after hip fracture surgery. Peripheral nerve blocks could improve outcomes through enhanced analgesia and decreased opioid related adverse events. We hypothesized that these benefits would translate into decreased resource use (length of stay [primary outcome] and costs), and better clinical outcomes (pneumonia and mortality). METHODS: The authors conducted a retrospective cohort study of hip fracture surgery patients in Ontario, Canada (2011 to 2015) using linked health administrative data. Multilevel regression, instrumental variable, and propensity scores were used to determine the association of nerve blocks with resource use and outcomes. RESULTS: The authors identified 65,271 hip fracture surgery patients; 10,030 (15.4%) received a block. With a block, the median hospital stay was 7 (interquartile range, 4 to 13) days versus 8 (interquartile range, 5 to 14) days without. Following adjustment, nerve blocks were associated with a 0.6-day decrease in length of stay (95% CI, 0.5 to 0.8). This small difference was consistent with instrumental variable (1.1 days; 95% CI, 0.9 to 1.2) and propensity score (0.2 days; 95% CI, 0.2 to 0.3) analyses. Costs were lower with a nerve block (adjusted difference, -$1,421; 95% CI, -$1,579 to -$1,289 [Canadian dollars]), but no difference in mortality (adjusted odds ratio, 0.99; 95% CI, 0.89 to 1.11) or pneumonia (adjusted odds ratio, 1.01; 95% CI, 0.88 to 1.16) was observed. CONCLUSIONS: Receipt of nerve blocks for hip fracture surgery is associated with decreased length of stay and health system costs, although small effect sizes may not reflect clinical significance for length of stay.

Research priorities in regional anaesthesia education and training: an international Delphi consensus survey.

OBJECTIVES: Education in regional anaesthesia covers several complex and diverse areas, from theoretical aspects to procedural skills, professional behaviours, simulation, curriculum design and assessment. The objectives of this study were to summarise these topics and to prioritise these topics in order of research importance. DESIGN: Electronic structured Delphi questionnaire over three rounds. SETTING: International. PARTICIPANTS: 38 experts in regional anaesthesia education and training, identified through the American Society of Regional Anesthesia Education Special Interest Group research collaboration. RESULTS: 82 topics were identified and ranked in order of prioritisation. Topics were categorised into themes of simulation, curriculum, knowledge translation, assessment of skills, research methodology, equipment and motor skills. Thirteen topics were ranked as essential research priority, with four topics each on simulation and curriculum, three topics on knowledge translation, and one topic each on methodology and assessment. CONCLUSIONS: Researchers and educators can use these identified topics to assist in planning and structuring their research and training in regional anaesthesia education.

Peripheral Nerve Blocks for Ambulatory Shoulder Surgery: A Population-based Cohort Study of Outcomes and Resource Utilization.

BACKGROUND: Nerve blocks improve early pain after ambulatory shoulder surgery; impact on postdischarge outcomes is poorly described. Our objective was to measure the association between nerve blocks and health system outcomes after ambulatory shoulder surgery. METHODS: We conducted a population-based cohort study using linked administrative data from 118 hospitals in Ontario, Canada. Adults having elective ambulatory shoulder surgery (open or arthroscopic) from April 1, 2009, to December 31, 2016, were included. After validation of physician billing codes to identify nerve blocks, we used multilevel, multivariable regression to estimate the association of nerve blocks with a composite of unplanned admissions, emergency department visits, readmissions or death within 7 days of surgery (primary outcome) and healthcare costs (secondary outcome). Neurology consultations and nerve conduction studies were measured as safety indicators. RESULTS: We included 59,644 patients; blocks were placed in 31,073 (52.1%). Billing codes accurately identified blocks (positive likelihood ratio 16.83, negative likelihood ratio 0.03). The composite outcome was not significantly different in patients with a block compared with those without (2,808 [9.0%] vs. 3,424 [12.0%]; adjusted odds ratio 0.96; 95% CI 0.89 to 1.03; P = 0.243). Healthcare costs were greater with a block (adjusted ratio of means 1.06; 95% CI 1.02 to 1.10; absolute increase $325; 95% CI $316 to $333; P = 0.005). Prespecified sensitivity analyses supported these results. Safety indicators were not different between groups. CONCLUSIONS: In ambulatory shoulder surgery, nerve blocks were not associated with a significant difference in adverse postoperative outcomes. Costs were statistically higher with a block, but this increase is not likely clinically relevant.

Association of peripheral nerve blocks with postoperative outcomes in ambulatory shoulder surgery patients: a single-centre matched-cohort study.

PURPOSE: Regional anesthesia may have immediate postoperative advantages compared with general anesthesia, but its impact on post-discharge outcomes is poorly described. Our objective was to measure the association between regional anesthesia and outcomes after ambulatory shoulder surgery. METHODS: We conducted a historical cohort study at The Ottawa Hospital. Adults ≥ 18 yr old having elective ambulatory shoulder surgery from January 1, 2011 to December 31, 2016 were included. Using one-to-many coarsened exact matching (CEM) to adjust for potential confounders, we matched peripheral nerve block (PNB) patients to those without a PNB. Within the matched cohort, we assessed whether PNBs were associated with our primary composite outcomes, comprising unplanned admissions, emergency department visits, readmissions, or death within 30 days of surgery. RESULTS: There were 1,623 patients who met the inclusion criteria; PNBs were placed in 1,382 (85.2%) patients. CEM matched 211 patients who did not receive a PNB to 950 patients with similar characteristics who did receive a PNB (n = 1,161; 71.5% of total cohort). In patients who received a PNB compared with those who had no PNB, there was no difference in risk of composite outcome (relative risk, 1.58; 95% confidence interval [CI], 0.83 to 3.01), or hospital costs (ratio of means 0.73; 95% CI, 0.21 to 2.49). CONCLUSION: Peripheral nerve blocks in ambulatory shoulder surgery were not associated with a significant difference in a composite of adverse postoperative outcomes. Nevertheless, given the lower than expected incidence and moderate effect size associating PNBs with post-discharge events, future large prospective trials are needed to assess post-discharge outcomes. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03309644). Registered 13 October 2017.

A Virtual Reality Simulation Model of Spinal Ultrasound: Role in Teaching Spinal Sonoanatomy.

BACKGROUND AND OBJECTIVES: Ultrasound assessment of the lumbar spine improves the success of spinal and epidural anesthesia, especially for patients with underlying difficult anatomy. To assist with the teaching and learning of ultrasound-guided neuraxial anesthesia, we have created an online interactive educational model (http://www.usra.ca/vspine.php and http://pie.med.utoronto.ca/vspine). The aim of the current study was to determine whether the virtual spine model improved the knowledge of neuraxial anatomy and sonoanatomy. METHODS: After obtaining ethics board approval and written participant consent, 14 anesthesia trainees with no prior experience with spine ultrasound imaging were included in this study. Construct validity was assessed using a pretest/posttest design to measure the knowledge acquired from self-study of the virtual spine simulation modules. Two tests (A and B) with 20 multiple-choice questions were used either for the pretest or posttest, at random in order to account for possible differences in difficulty between the 2 tests. These tests were administered immediately before and after a 1-hour training session using the spine ultrasound model. RESULTS: Fourteen anesthesia trainees completed the study. Seven used test A as the pretest (group A), and 7 used test B as the pretest (group B). Both groups showed a statistically significant improvement (P < 0.05) in test scores after a 1-hour session with the spine ultrasound model. The mean scores were 55% (SD, 11.2%) on the pretest and 77% (SD, 8.7%) on the posttest. CONCLUSIONS: The study demonstrated that after 1 hour of self-study by the trainees on the spine ultrasound model test scores improved by 40%.

Continuous infraclavicular brachial plexus blockade: effect on survival of replanted digits.

In replantation surgery, the use of continuous brachial plexus blockade (CBPB) is popular as it improves postoperative analgesia and vascular flow. The aim of our study was to determine whether CBPB may affect the odds of survivability of replanted digit(s). A four-year retrospective chart review was performed and various parameters affecting replant survival were examined. Outcome was recorded as successful if the transplanted digit(s) survived six months after discharge. All the independent variables were forced into a regression model without using a specific variable selection algorithm. The data for 146 patients was obtained from our chart review. The success rate of replanted digits in the patients reviewed was 65.8%. The logistic regression model showed a relation between the number of digits injured and replanted digit(s) survival. Our study showed that CBPB has no effect on the survivability of the replanted digit(s) till six months after hospital discharge.

The utility of ultrasound imaging in predicting ease of performance of spinal anesthesia in an orthopedic patient population.

BACKGROUND AND OBJECTIVES: Ultrasonography of the spine improves technical performance of spinal anesthesia, but what is unclear is whether it can predict difficulty. We tested the hypothesis that a good ultrasound view at a given intervertebral level is associated with absence of technical difficulty. METHODS: We performed preprocedural ultrasound of the L1-S1 intervertebral spaces in 100 patients undergoing orthopedic surgery. Visibility of the ligamentum flavum-dura mater and the posterior longitudinal ligament was evaluated using paramedian sagittal oblique and transverse midline (TM) views. Views were classified as good if both of these structures were visible on ultrasound. An operator, blinded to the ultrasound scan, performed surface landmark-guided spinal anesthesia using a midline approach. Absence of technical difficulty was defined as successful dural puncture within 2 skin punctures or 10 needle passes. RESULTS: A good TM view had the best diagnostic accuracy; if this view was obtained, absence of technical difficulty with dural puncture at that level was highly likely (positive predictive value, 85%). Dural puncture could still be feasible despite the absence of a good TM view, as reflected by a negative predictive value of 30%. This was attributed to the limitations of ultrasound imaging in this patient population, as well as the low overall prevalence of difficult dural puncture. Parasagittal oblique views did not have significant diagnostic utility for a midline needle approach. CONCLUSIONS: Ultrasound can be useful in predicting the absence of technical difficulty in performing dural puncture and thus in selecting the optimal intervertebral level for spinal anesthesia.