Simulation-Based Analysis of Trial Design in Regional Anesthesia.

Background: In regional anesthesia, the efficacy of novel blocks is typically evaluated using randomized controlled trials (RCTs), the findings of which are aggregated in systematic reviews and meta-analyses. Systematic review authors frequently point out the small sample size of RCTs as limiting conclusions from this literature. We sought to determine via statistical simulation if small sample size could be an expected property of RCTs focusing on novel blocks with typical effect sizes. Methods: We simulated the conduct of a series of RCTs comparing a novel block versus placebo on a single continuous outcome measure. Simulation analysis inputs were obtained from a systematic bibliographic search of meta-analyses. Primary outcomes were the predicted number of large trials (empirically defined as N ≥ 256) and total patient enrollment. Results: Simulation analysis predicted that a novel block would be tested in 16 RCTs enrolling a median of 970 patients (interquartile range (IQR) across 1000 simulations: 806, 1269), with no large trials. Among possible modifications to trial design, decreasing the statistical significance threshold from p < 0.05 to p < 0.005 was most effective at increasing the total number of patients represented in the final meta-analysis, but was associated with early termination of the trial sequence due to futility in block vs. block comparisons. Conclusion: Small sample size of regional anesthesia RCTs comparing novel block to placebo is a rational outcome of trial design. Feasibly large trials are unlikely to change conclusions regarding block vs. placebo comparisons.

Efficacy of regional anesthesia techniques for postoperative analgesia in patients undergoing major oncologic breast surgeries: a systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: The optimal regional technique to control pain after breast cancer surgery remains unclear. We sought to synthesize available data from randomized controlled trials comparing pain-related outcomes following various regional techniques for major oncologic breast surgery. METHODS: In a systematic review and network meta-analysis, we searched trials in PubMed, Embase Scopus, Medline, Cochrane Central and Google Scholar, from inception to 31 July 2020, for commonly used regional techniques. The primary outcome was the 24-hr resting pain score measured on a numerical rating score of 0-10. We used surface under the cumulative ranking curve (SUCRA) to establish the probability of an intervention ranking highest. The analysis was performed using the Bayesian random effects model, and effect sizes are reported as 95% credible interval (Crl). We conducted cluster-rank analysis by combining 24-hr pain ranking with 24-hr opioid use or incidence of postoperative nausea and vomiting. RESULTS: Seventy-nine randomized controlled trials containing 11 different interventions in 5,686 patients were included. The SUCRA values of the interventions for 24-hr resting pain score were continuous paravertebral block (0.83), serratus anterior plane block (0.76), continuous wound infusion (0.76), single-level paravertebral block (0.68), erector spinae plane block (0.59), modified pectoral block (0.49), intercostal block (0.45), multilevel paravertebral block (0.41), wound infiltration (0.33), no intervention (0.12), and placebo (0.08). When compared with placebo, the continuous paravertebral block (mean difference, 1.26; 95% Crl, 0.43 to 2.12) and serratus anterior plane block (mean difference, 1.12; 95% Crl, 0.32 to 1.9) had the highest estimated probability of decreasing 24-hr resting pain scores. Cluster ranking analysis combining 24-hr resting pain scores and opioid use showed that most regional analgesia techniques were more effective than no intervention or placebo. Nevertheless, wound infiltration and continuous wound infusion may be the least effective active interventions for reducing postoperative nausea and vomiting. CONCLUSION: Continuous paravertebral block and serratus anterior plane block had a high probability of reducing pain at 24 hr after major oncologic breast surgery. The certainty of evidence was moderate to very low. Future studies should compare different regional anesthesia techniques, including surgeon-administered techniques such as wound infiltration or catheters. Trials comparing active intervention with placebo are unlikely to change clinical practice. STUDY REGISTRATION: PROSPERO (CRD42020198244); registered 19 October 2020.

RéSUMé: CONTEXTE: La technique régionale optimale pour contrôler la douleur après une chirurgie de cancer du sein n'a pas encore été clairement établie. Nous avons cherché à synthétiser les données disponibles provenant d'études randomisées contrôlées comparant les issues liées à la douleur à la suite de diverses techniques régionales pour la chirurgie mammaire oncologique majeure. MéTHODE: Dans une revue systématique et une méta-analyse de réseau, nous avons recherché les études portant sur les techniques régionales couramment utilisées dans les bases de données PubMed, Embase Scopus, Medline, Cochrane Central et Google Scholar, de leur création au 31 juillet 2020. Le critère d'évaluation principal était le score de douleur au repos à 24 heures mesuré sur une échelle d'évaluation numérique de 0 à 10. Nous avons utilisé la surface sous la courbe de classement cumulatif (SUCRA) afin d'établir la probabilité qu'une intervention soit cotée plus haut. L'analyse a été réalisée à l'aide d'un modèle bayésien à effets aléatoires, et les tailles d'effet sont rapportées comme intervalle crédible à 95 % (ICr). Nous avons effectué une analyse de classement en grappes en combinant le classement de douleur sur 24 heures avec la consommation d'opioïdes sur 24 heures ou l'incidence des nausées et vomissements postopératoires. RéSULTATS: Soixante-dix-neuf études randomisées contrôlées comportant 11 interventions différentes chez 5686 patientes ont été incluses. Les valeurs SUCRA des interventions pour le score de douleur au repos à 24 heures étaient le bloc paravertébral continu (0,83), le bloc du plan antérieur du serratus (0,76), la perfusion continue de la plaie (0,76), le bloc paravertébral à un seul niveau (0,68), le bloc du plan des muscles érecteurs du rachis (0,59), le bloc pectoral modifié (0,49), le bloc intercostal (0,45), le bloc paravertébral multiniveau (0,41), l'infiltration de plaie (0,33), l'absence d'intervention (0,12) et le placebo (0,08). Par rapport au placebo, le bloc paravertébral continu (différence moyenne, 1,26; ICr 95 %, 0,43 à 2,12) et le bloc du plan antérieur du serratus (différence moyenne, 1,12; ICr 95 %, 0,32 à 1,9) ont affiché la probabilité estimée la plus élevée de diminuer les scores de douleur au repos à 24 heures. L'analyse du classement des grappes combinant les scores de douleur au repos et la consommation d'opioïdes à 24 heures a montré que la plupart des techniques d'analgésie régionale étaient plus efficaces que l'absence d'intervention ou un placebo. Néanmoins, l'infiltration de la plaie et la perfusion continue de la plaie semblaient être les interventions actives les moins efficaces pour réduire les nausées et vomissements postopératoires. CONCLUSION: Le bloc paravertébral continu et le bloc du plan antérieur du serratus ont affiché une forte probabilité de réduire la douleur 24 heures après une chirurgie mammaire oncologique majeure. La fiabilité des données probantes allait de modérée à très faible. Les études futures devraient comparer différentes techniques d'anesthésie régionale, y compris les techniques administrées par le chirurgien telles que l'infiltration de plaie ou les cathéters. Il est peu probable que les études comparant une intervention active à un placebo modifient la pratique clinique. Enregistrement de l'étude : PROSPERO (CRD42020198244); enregistrée le 19 octobre 2020.

Erector Spinae Plane Block versus Continuous Perineural Local Anesthetic Infusion for Postoperative Pain Control After Supraclavicular Decompression for Neurogenic Thoracic Outlet Syndrome: A Matched Case-Control Comparison.

OBJECTIVE: The purpose of this study was to determine if single injection erector spinae plane blocks are associated with improved pain control, opioid use, numbness, length of stay, or patient satisfaction compared to intraoperatively placed continuous perineural infusion of local anesthetic after decompression of neurogenic thoracic outlet syndrome. METHODS: This is a retrospective cohort study at a tertiary academic center of eighty patients that underwent supraclavicular decompression for thoracic outlet syndrome between May 2019 and January 2020. Forty consecutive patients treated with single-injection preoperative erector spinae plane blocks were retrospectively compared to 40 age- and gender-matched controls treated with continuous perineural infusion. RESULTS: The primary outcome of mean pain scores was not significantly different between the erector spinae and perineural infusion groups over the three-day study period (4.2-5.3 vs 3.0-5.1 P=0.08). On post-operative day 0, mean pain scores were significantly higher in the erector spinae group (4.2 vs 3.0, P=0.02). While statistically significant, the score was still lower in the erector spinae group on day 0 than on day 1,2, or 3 in either group. Opioid use, nausea, length of stay and patient satisfaction were also similar. Upper extremity numbness was significantly less severe in the erector spinae group (36% vs 73% moderate-extreme, P=0.03) at 6-month follow-up. CONCLUSIONS: Seventy-two-hour perineural local anesthetic infusion did not provide superior analgesia compared to preoperative single-injection erector spinae blocks. Furthermore, there was significantly less long-term postoperative numbness associated with erector spinae blocks compared to perineural local anesthetic infusion.

Enhanced Recovery With Paravertebral and Transversus Abdominis Plane Blocks in Microvascular Breast Reconstruction.

PURPOSE: We have shown previously that a preoperative paravertebral nerve block is associated with improved postoperative recovery in microvascular breast reconstruction. The purpose of this study was to compare the outcomes of a complete enhanced recovery after surgery (ERAS) protocol with complete regional anesthesia coverage to our traditional care with paravertebral block. PATIENTS AND METHODS: This was a retrospective cohort study of 83 patients who underwent autologous breast reconstruction by T.M.M. between May 2014 and February 2018 at a tertiary academic center. Patients in the ERAS group were additionally administered acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), gabapentin, a transversus abdominis plane block (liposomal or plain bupivacaine), and primarily oral opioids postoperatively. The patients were mobilized earlier with more rapid diet progression. All patients received a preoperative paravertebral block. RESULTS: Forty-four patients in the ERAS cohort were compared with 39 retrospective controls. The 2 groups were similar with respect to demographics and comorbidities. The ERAS cohort required significantly less opioids (291 vs 707 mg oral morphine equivalent, P < .0001) with unchanged postoperative pain scores and a shorter time to oral only opioid use (16.0 vs 78.2 hours, P < .0001). Median length of stay (3.20 vs 4.62, P < .0001) and time to independent ambulation (1.86 vs 2.88, P < .0001) were also significantly decreased in the ERAS cohort. Liposomal bupivacaine use did not significantly affect the results (P ⩾ .2). CONCLUSIONS: Implementation of a robust enhanced recovery protocol with complete regional anesthesia coverage was associated with significantly decreased opioid use despite unchanged pain scores, with improved markers of recovery including length of stay, time to oral only narcotics, and time to independent ambulation.

The Analgesic Effects of Liposomal Bupivacaine versus Bupivacaine Hydrochloride Administered as a Transversus Abdominis Plane Block after Abdominally Based Autologous Microvascular Breast Reconstruction: A Prospective, Single-Blind, Randomized, Controlled Trial.

BACKGROUND: Postoperative pain control after abdominally based autologous microvascular breast reconstruction is critical to functional recovery, patient satisfaction, and early discharge. The transversus abdominis plane block using 0.25% bupivacaine hydrochloride has been shown to be effective, but it is limited by a short duration of effect. Liposomal bupivacaine is a recently U.S. Food and Drug Administration-approved preparation of bupivacaine that can provide up to 72 hours of pain relief. The purpose of this randomized, controlled trial was to compare the analgesic efficacy of liposomal bupivacaine and conventional bupivacaine. METHODS: This study was a prospective, single-blind, randomized, controlled trial of 44 patients undergoing abdominally based autologous breast reconstruction between June of 2016 and February of 2018 performed by a single surgeon. Each patient was randomized to receive either 266 mg of liposomal bupivacaine or 75 mg of conventional bupivacaine to the transversus abdominis plane at the conclusion of the reconstruction procedure. All patients were managed postoperatively according to an enhanced recovery protocol. RESULTS: In our study of 44 patients, 22 patients received a transversus abdominis plane block with conventional bupivacaine and 22 patients received liposomal bupivacaine. There were no significant differences with regard to any outcome measure. No differences were found in total opioid consumption (p = 0.98), Quality of Recovery-15 scores (p = 0.72), pain scores (p = 0.39), or length of stay (p = 0.20). CONCLUSION: In the setting of a robust enhanced recovery after surgery protocol, liposomal bupivacaine does not confer advantages over conventional bupivacaine when used as single injections in transversus abdominis plane blocks after abdominally based microvascular breast reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Paravertebral Blocks Reduce Narcotic Use Without Affecting Perfusion in Patients Undergoing Autologous Breast Reconstruction.

BACKGROUND: Autologous breast reconstruction offers excellent long term outcomes after mastectomy. However, maintaining adequate postoperative analgesia remains challenging. Use of paravertebral blocks (PVBs) reduces postoperative narcotic use and length of stay, and enhanced recovery protocols with mixed analgesia methods are gaining popularity, but few studies have explored the intraoperative effects of these interventions. METHODS: Patients who underwent abdominally based autologous breast reconstruction between 2010 and 2016 were compiled into a retrospective database. We used electronic medical records to determine demographics, as well as perioperative and intraoperative vital signs and narcotic, anxiolytic, crystalloid, colloid, blood product, and vasopressor requirements, and postoperative complications. Results were compared between patients who had a PVB and those who did not and those who had a PVB alone and those who followed our enhanced recovery protocol using standard statistical methods and adjusting for preoperative values. RESULTS: A total of 170 patients were included in the study. Sixty-six had a PVB, and 104 did not. Of the 66 who had a PVB, 19 followed our enhanced recovery protocol. Patients who did not have a PVB required 171.6 mg of total narcotic medication in the perioperative period, those with a PVB alone required 146.9 mg, and those who followed the ERAS protocol 95.2 mg (p = 0.01). There was no difference in intraoperative mean arterial pressure, time with mean arterial pressure <80% of baseline, vasopressor use, or fluid requirement. There was no difference in complication rate. CONCLUSIONS: PVBs and an enhanced recovery protocol reduce the use of narcotic medications in autologous breast reconstruction without impacting intraoperative hemodynamics. Breast reconstruction after mastectomy restores body image and improves health-related quality of life, satisfaction with appearance and physical, psychosocial, and sexual well-being (Donovan et al. in J Clin Oncol 7(7):959-968, 1989; Eltahir et al. in Plast Reconstr Surg 132(2):201e-209e, 2013; Jagsi et al. in Ann Surg 261(6):1198-1206, 2015). For patients pursuing breast reconstruction, there are two major options: prosthetic (tissue expander/implant) or autologous reconstruction. However, while providing exceptional long-term outcomes, postoperative pain and length of hospital stay remains a major challenge preventing more widespread adoption of autologous breast reconstruction (Albornoz et al. in Plast Reconstr Surg 131(1):15-23, 2013; Gurunluoglu et al. in Ann Plast Surg 70(1):103-110, 2013; Kulkarni et al. in Plast Reconstr Surg 132(3):534-541, 2013; Sbitany et al. in Plast Reconstr Surg 124(6):1781-1789, 2009). Acute postoperative pain contributes to prolonged hospital stays, increased narcotic use, and associated risks of the aforementioned.

Preoperative Paravertebral Block Improves Postoperative Pain Control and Reduces Hospital Length of Stay in Patients Undergoing Autologous Breast Reconstruction after Mastectomy for Breast Cancer.

BACKGROUND: Postoperative pain is a major challenge for patients undergoing breast reconstruction after surgical treatment of breast cancer, resulting in prolonged hospitalizations and additional resource utilization. Evidence on the efficacy of techniques to minimize postoperative pain in autologous breast reconstruction is lacking. We sought to determine whether preoperative paravertebral block (PVB), a regional anesthetic technique, affects postoperative pain control and hospital length of stay (LOS) in patients undergoing autologous breast reconstruction. METHODS: Consecutive patients undergoing postmastectomy autologous breast reconstruction between 2012 and 2015 were identified from a prospectively collected database to compare those who received PVB to those who did not. Primary outcomes included self-reported pain score, time to oral-only narcotic usage (TTON), and LOS. Sample differences were compared using Wilcoxon rank-sum and Chi square tests for continuous and categorical variables. Kaplan-Meier analysis was used to evaluate TTON and LOS, with Mantel-Cox test used to compare groups. RESULTS: Of 78 patients, 39 received PVB and 39 did not. Study groups did not differ regarding age, body mass index, American Society of Anesthesiologists class, mastectomy type, flap type, or cancer stage (p > 0.05). Patients in the PVB group reported significantly lower postoperative pain at 2 (p < 0.01) and 24 h (p < 0.01) and shorter median TTON (66 vs. 76 h, p < 0.01). Importantly, median LOS was reduced for patients receiving a PVB in both hours (95 vs. 116, p < 0.01) and hospital nights (4 vs. 5, p = 0.05). CONCLUSIONS: Preoperative PVB is associated with improved postoperative pain control and shorter hospitalizations for patients with breast cancer undergoing postmastectomy autologous reconstruction.

The utility of pre-residency standardized tests for anesthesiology resident selection: the place of United States Medical Licensing Examination scores.

BACKGROUND: The resident selection process could be improved if United States Medical Licensing Examination (USMLE) scores obtained during residency application were found to predict success on the American Board of Anesthesiology (ABA) written examination (part 1). In this study, we compared USMLE performance during medical school to anesthesiology residency standardized examination performance. METHODS: Sixty-nine anesthesiology residents' USMLE, ABA/American Society of Anesthesiologists (ASA) In-Training Examination, and ABA written board examination (part 1) scores were compared. Linear regression, adjusted Pearson partial correlation, multiple regression, and analysis of variance were used to cross-correlate pre-residency and intra-residency scores. Residents' school of medicine location and year of graduation were noted. RESULTS: Both USMLE step 1 and step 2 Clinical Knowledge examinations correlated significantly with all intra-residency standardized tests. Averaged step 1 and step 2 USMLE score correlated to ABA written examination (part 1) score with a slope of 0.72 and r of 0.48 (P = 0.001). CONCLUSIONS: The USMLE is a significant predictor of residency ABA/ASA In-Training Examination and ABA written examination performance in anesthesiology. Our program has significantly increased its average written board examination performance while increasing the relative importance of USMLE in resident selection.

Patient knowledge of physician responsibilities and their preferences for care in ophthalmology teaching clinics.

PURPOSE: To determine how well patients understand the hierarchy of a teaching hospital, what factors influence patient knowledge, and how patients feel about their role in training physicians. DESIGN: Prospective cross-sectional survey. PARTICIPANTS: A total of 312 patients attending 1 of 3 ophthalmology clinics at the Kresge Eye Institute in July 2006. METHODS: Survey of knowledge about the training and responsibilities of medical students, residents, and attending physicians was conducted, as well as subjective evaluation regarding patient comfort with treatment by physicians in training. Knowledge Score was correlated with subjective Comfort Score and demographics using analysis of variance. MAIN OUTCOME MEASURES: Knowledge Score and subjective Comfort Score. RESULTS: A total of 312 surveys were completed. Some 56% of questions were answered correctly. Higher education was the only significant factor for increased Knowledge Score (P<0.001). Respondents with a higher Knowledge Score had a correspondingly higher Comfort Score (P = 0.004) and are significantly more comfortable with treatment provided by physicians in training (residents). Clinic site (P = 0.002) and increasing age (P = 0.02) are also significant independent factors for increased comfort with treatment provided by physicians in training. CONCLUSIONS: Patients have moderate knowledge of the training and hierarchy of medical students, residents, and attending physicians. Increased patient knowledge is a significant independent factor for increased patient comfort with treatment by physicians in training. Clinic site and increased age are also significant factors for comfort with treatment by physicians in training. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.