Factors to consider for fascial plane blocks' success in acute and chronic pain management.

The outcome of fascial plane blocks (FPBs) has a certain variability that may depend on many factors, which can be divided into three main categories: operator-related, patient-related and drug-related. Operator-related factors include personal skills, choice of needle and injection modalities. Patient variables include anthropometric features, the type of targeted fascia, anatomical variants, patient positioning, muscle tone and breathing. Ultimately, efficacy, onset, and duration of fascial blocks may be affected by characteristics of the injected solution, including the type of local anesthetic, volume, concentration, pH, temperature and the use of adjuvants. In this article, we investigated all the factors that may influence the outcome of FPBs from a generic perspective, without focusing on any specific technique. Also, we provided suggestions to optimize techniques for everyday practitioners and insights to researchers for future studies.

A mathematical framework for evo-devo dynamics.

Natural selection acts on phenotypes constructed over development, which raises the question of how development affects evolution. Classic evolutionary theory indicates that development affects evolution by modulating the genetic covariation upon which selection acts, thus affecting genetic constraints. However, whether genetic constraints are relative, thus diverting adaptation from the direction of steepest fitness ascent, or absolute, thus blocking adaptation in certain directions, remains uncertain. This limits understanding of long-term evolution of developmentally constructed phenotypes. Here we formulate a general, tractable mathematical framework that integrates age progression, explicit development (i.e., the construction of the phenotype across life subject to developmental constraints), and evolutionary dynamics, thus describing the evolutionary and developmental (evo-devo) dynamics. The framework yields simple equations that can be arranged in a layered structure that we call the evo-devo process, whereby five core elementary components generate all equations including those mechanistically describing genetic covariation and the evo-devo dynamics. The framework recovers evolutionary dynamic equations in gradient form and describes the evolution of genetic covariation from the evolution of genotype, phenotype, environment, and mutational covariation. This shows that genotypic and phenotypic evolution must be followed simultaneously to yield a dynamically sufficient description of long-term phenotypic evolution in gradient form, such that evolution described as the climbing of a fitness landscape occurs in "geno-phenotype" space. Genetic constraints in geno-phenotype space are necessarily absolute because the phenotype is related to the genotype by development. Thus, the long-term evolutionary dynamics of developed phenotypes is strongly non-standard: (1) evolutionary equilibria are either absent or infinite in number and depend on genetic covariation and hence on development; (2) developmental constraints determine the admissible evolutionary path and hence which evolutionary equilibria are admissible; and (3) evolutionary outcomes occur at admissible evolutionary equilibria, which do not generally occur at fitness landscape peaks in geno-phenotype space, but at peaks in the admissible evolutionary path where "total genotypic selection" vanishes if exogenous plastic response vanishes and mutational variation exists in all directions of genotype space. Hence, selection and development jointly define the evolutionary outcomes if absolute mutational constraints and exogenous plastic response are absent, rather than the outcomes being defined only by selection. Moreover, our framework provides formulas for the sensitivities of a recurrence and an alternative method to dynamic optimization (i.e., dynamic programming or optimal control) to identify evolutionary outcomes in models with developmentally dynamic traits. These results show that development has major evolutionary effects.

How development affects evolution.

Natural selection acts on developmentally constructed phenotypes, but how does development affect evolution? This question prompts a simultaneous consideration of development and evolution. However, there has been a lack of general mathematical frameworks mechanistically integrating the two, which may have inhibited progress on the question. Here, we use a new mathematical framework that mechanistically integrates development into evolution to analyse how development affects evolution. We show that, while selection pushes genotypic and phenotypic evolution up the fitness landscape, development determines the admissible evolutionary pathway, such that evolutionary outcomes occur at path peaks rather than landscape peaks. Changes in development can generate path peaks, triggering genotypic or phenotypic diversification, even on constant, single-peak landscapes. Phenotypic plasticity, niche construction, extra-genetic inheritance, and developmental bias alter the evolutionary path and hence the outcome. Thus, extra-genetic inheritance can have permanent evolutionary effects by changing the developmental constraints, even if extra-genetically acquired elements are not transmitted to future generations. Selective development, whereby phenotype construction points in the adaptive direction, may induce adaptive or maladaptive evolution depending on the developmental constraints. Moreover, developmental propagation of phenotypic effects over age enables the evolution of negative senescence. Overall, we find that development plays a major evolutionary role.

Two years follow-up of continuous erector spinae plane block in a patient with upper extremity complex regional pain syndrome type I.

BACKGROUND: Recalcitrant complex regional pain syndrome (CRPS) type 1 is a devastating condition. CASE PRESENTATION: We report a case of a patient in their twenties with left hand and forearm CRPS type I, transiently responsive to spinal cord stimulation, thoracic sympathectomy, and multimodal analgesia. The investigators initiated a trial of a single-shot erector spinae plane block at the T2 level, resulting in a clinically significant improvement in pain, function, vasomotor and sudomotor symptoms transiently for a 36-hour interval. As a result, a permanent e-port catheter implantation under combined ultrasound and fluoroscopic guidance was trialed. Two-year follow-up of the continuous erector spinae plane block (CESPB) indicated an 80% reduction in pain scores from baseline, and a 50% reduction in opiate consumption, with a clinically significant reduction in swelling, color changes, allodynia, and temperature asymmetry. CONCLUSION: Recalcitrant CRPS type 1 is a challenging life-altering condition that results in a cyclical triad of chronic pain, disability, and impaired psychosocial health. The profound and prolonged analgesic response to CESPB, highlights the clinical utility of this technique, and warrants more clinical investigation.

Eusociality through conflict dissolution.

Eusociality, where largely unreproductive offspring help their mothers reproduce, is a major form of social organization. An increasingly documented feature of eusociality is that mothers induce their offspring to help by means of hormones, pheromones or behavioural displays, with evidence often indicating that offspring help voluntarily. The co-occurrence of maternal influence and offspring voluntary help may be explained by what we call the converted helping hypothesis, whereby maternally manipulated helping subsequently becomes voluntary. Such hypothesis requires that parent-offspring conflict is eventually dissolved-for instance, if the benefit of helping increases sufficiently over evolutionary time. We show that help provided by maternally manipulated offspring can enable the mother to sufficiently increase her fertility to transform parent-offspring conflict into parent-offspring agreement. This conflict-dissolution mechanism requires that helpers alleviate maternal life-history trade-offs, and results in reproductive division of labour, high queen fertility and honest queen signalling suppressing worker reproduction-thus exceptionally recovering diverse features of eusociality. As such trade-off alleviation seemingly holds widely across eusocial taxa, this mechanism offers a potentially general explanation for the origin of eusociality, the prevalence of maternal influence, and the offspring's willingness to help. Overall, our results explain how a major evolutionary transition can happen from ancestral conflict.

Continuous erector spinae plane block versus intercostal nerve block in patients undergoing video-assisted thoracoscopic surgery: a pilot randomized controlled trial.

BACKGROUND: The optimal analgesia method in video-assisted thoracoscopic surgery (VATS) remains controversial. Intercostal nerve blockade (ICNB) is limited by its duration of action. The erector spinae plane (ESP) block has the potential to provide satisfactory analgesia for VATS; however, the effectiveness of continuous ESP versus surgeon-performed ICNB has not been investigated. The objectives of this study were to establish feasibility of patient recruitment and follow-up before undertaking a fully powered randomized controlled trial (RCT); and, secondarily, to compare opioid usage, pain control, and sensory blockade. METHODS: This feasibility RCT was undertaken at St Joseph's Hospital, Hamilton, Ontario, Canada, and included 24 patients (>18 years) having elective VATS with at least one overnight stay. Exclusion criteria were patient refusal, body mass index >40 kg/m2, contraindications to neuraxial analgesia techniques as per the American Society of Regional Anesthesia and Pain guidelines, known allergy to local anesthetics, language or comprehension barriers, procedures with a higher chance of open surgery, and regular opioid use for ≥3 months preoperatively. Patients underwent either continuous ESP (n=12) or surgeon-performed ICNB (n=12). All patients received routine intraoperative anesthesia care and multimodal analgesia. Feasibility criteria were recruitment rate of two patients/week and full follow-up in all patients in-hospital. We compared opioid consumption, postoperative pain scores (0-10 numerical rating scale), adverse events, patient satisfaction, and distribution of sensory blockade as clinical outcomes (secondary). RESULTS: Feasibility of primary outcomes was successfully demonstrated. Five patients had an epidural in anticipation of open surgery. Mean opioid consumption as equivalent morphine units was less in the ESP group over the first 24 h (mean difference, 1.63 [95% CI -1.20 to 4.45]) and 48 h (mean difference, 2.34 [95% CI -1.93 to 6.61]). There were no differences in adverse effects. CONCLUSIONS: A fully powered RCT is feasible with modifications. Our results also suggest that continuous ESP is safe and can decrease opioid needs. However, it is important to consider procedures to improve compliance to protocol and adherence to assigned interventions. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT03176667 . Registered June 5, 2017.

Continuous Erector Spinae Plane Block for Refractory Chest Wall Pain in a Patient With Metastatic Breast Cancer: A Case Report.

In this case report, we described the use of the continuous erector spinae plane (ESP) block in a patient presenting with severe chest wall pain due to terminal metastatic breast cancer. Her pain was refractory to most treatment modalities despite being on huge doses of parenteral opioids for 6 months. A single shot ESP block was initially trialed, which provided her complete pain relief. This was followed by an ESP catheter insertion and continuous infusion of local anesthetic, which helped her wean off the parenteral opioids over the next 4 days. She was discharged home with the catheter in situ, attached to a delivery pump.

Evaluation of Sensory Mapping of Erector Spinae Plane Block.

BACKGROUND: Erector spinae plane (ESP) block is an effective regional analgesic technique for thoracic and abdominal pain. The volume of local anesthetic (LA) needed to produce sensory block in the spinal segment is unknown. OBJECTIVES: The aim of the present study was to examine the extent of dermatomal spread following ultrasound-guided administration of ESP block, with a fixed-volume dose of a LA at the midthoracic area for analgesia in acute thoracic pain patients. Secondary objectives were postprocedure analgesia and patient satisfaction. STUDY DESIGN: This research used a prospective unicentric exploratory cohort design. SETTING: The study was conducted at an academic university hospital. METHODS: A total of 18 patients with acute severe chest pain including rib fractures, thoracic postoperative rescue analgesia, zoster herpetic neuritis, and myofascial pain syndrome received ESP block under ultrasound guidance at the T5-T7 levels. Twenty mL of 0.5% plain bupivacaine was injected. Evaluation of the sensory block was carried out 60 minutes following the completion of the ESP block via a change in sensation to pinprick and cold methods. The Visual Analog Scale (VAS) for pain was recorded one hour after the procedure. Patient satisfaction was reported using a 4-point Likert scale. This study was registered with the clinicaltrials.gov database (identifier: NCT03831581). RESULTS: Sixteen patients had a successful ESP block; 2 patients were excluded for a failed block. The mean dermatomal spread was 9 (range, 8-11). VAS scores improved by at least 50% from baseline (P < .05), one hour after the ESP block. The degree of satisfaction reported by all patients on the Likert scale was 4 points. No major complications were observed. LIMITATIONS: This study was limited by its sample size. CONCLUSIONS: An ultrasound-guided ESP block with a single injection at the midthoracic level with 20 mL of 0.5% plain bupivacaine provides a mean dermatomal spread of 9 dermatomes (range, 8-11) with a high rate of analgesic efficacy and low incidence of adverse effects. KEY WORDS: Acute pain, dermatomal spread, erector spine plane nerve block, thoracic pain, thoracic postoperative analgesia.

Multimodal Anesthesia via Opioid-Free Analgesia and Erector Spinae Plane Block.

Multimodal anesthesia, which combines general and epidural anesthesia, is used in surgical cases in which a large or painful incision is anticipated. However, both epidural blocks and opioid-based analgesia have limitations in application. Here, we present a case of supra-infraumbilical laparotomy in a patient whose history of neurostimulator use and marked scoliosis discouraged the placement of an epidural catheter and whose prior adverse response to opioids prohibited their use. The intraoperative and postoperative management of this patient consisted of a combination of analgesia without opioids and erector spinae plane block. Adequate analgesia was achieved, and intraoperative or postoperative opioids were not required. This case illustrates the importance of mastering alternative and multimodal analgesia techniques that can be used in place of classical analgesia techniques when classical analgesia techniques are not appropriate.

Randomized control trial of ultrasound-guided erector spinae block versus shoulder periarticular anesthetic infiltration for pain control after arthroscopic shoulder surgery: Study protocol clinical trial (SPIRIT compliant).

INTRODUCTION: Moderate to severe postoperative pain and associated opioid use may interfere with patients' well-being and course of recovery. Regional anesthetic techniques provide an opportunity for opioid sparing and improved patient outcomes. A new regional technique called the erector spinae plane (ESP) block has the potential to provide effective analgesia after shoulder arthroscopy with minimal risks and decreased opioid consumption. Our primary objective is to determine whether, in patients who undergo arthroscopic shoulder surgery, a preoperative ESP block reduces pain scores as compared to periarticular infiltration at the end of surgery. Additionally, we will also examine other factors such as opioid consumption, sensory block, adverse events, patient satisfaction, and persistent pain. METHODS: This is a 2-arm, single-center, parallel-design, double-blind randomized controlled trial of 60 patients undergoing arthroscopic shoulder surgery. Eligible patients will be recruited in the preoperative clinic. Using a computer-generated randomization, with a 1:1 allocation ratio, patients will be randomized to either the ESP or periarticular infiltration group. Patients will be followed in hospital in the postanesthesia care unit, at 24 hours, and at 1 month. The study with be analyzed as intention-to-treat. DISCUSSION: This study will inform an evidence-based choice in recommending ESP block for shoulder arthroscopy, as well as providing safety data. The merits of the study include its double dummy blinding to minimize observer bias, and its assessment of patient important outcomes, including pain scores, opioid consumption, and patient satisfaction. This study will also help provide an estimate of the incidence of side effects and complications of the ESP block. TRIAL REGISTRATION NUMBER: NCT03691922; Recruited Date of registration: October 2, 2018.

A magnetic resonance imaging study of local anesthetic spread in patients receiving an erector spinae plane block.

PURPOSE: Despite the popularity of the erector spinae plane (ESP) block, both the mechanism of the block and the extent of injectate spread is unclear. This study used magnetic resonance imaging (MRI) to evaluate the spread of local anesthetic injectate following ESP blocks in six patients with pain. METHODS: Six patients received a left-sided ultrasound-guided ESP block at the T10 level. The injectate contained 29.7 mL of 0.25% bupivacaine and 0.3 mL of gadolinium in the first patient, with an additional 5 mL (50 mg) of triamcinolone in the subsequent five patients. Sensory block to pinprick and cold as well as pain score (with 0 indicating no pain and 10 being maximum pain) were assessed 20 and 30 min respectively following the ESP block. MRI was performed one hour after the block. RESULT: The injectate spread into the intercostal space and neural foramina in all six patients, but the extent of cephalocaudal spread was variable, with a median [interquartile range] spread of 9 [5-11] and 3 [2-6] levels for the intercostal space and neural foramina, respectively. The injectate also spread extensively within the erector spinae muscles. Spread to the epidural space was seen in two patients. Sensory block was achieved in both ventral and dorsal dermatomes in all patients, though the extent was variable. CONCLUSIONS: Our study showed that the ESP block injectate consistently spread to the erector spinae muscles, neural foramina, and intercostal space. It was associated with sensory changes and pain relief in the dorsal and ventral thoracic and abdominal walls. Nevertheless, the extent of spread to the neural foramina and intercostal space, and the sensory block itself, was highly variable.

RéSUMé: OBJECTIF: Malgré la popularité du bloc plan des érecteurs du rachis (PER), le mécanisme du bloc et l'ampleur de la diffusion du produit injecté ne sont pas clairement connus. Cette étude a utilisé l'imagerie par résonance magnétique (IRM) pour évaluer la diffusion de l'anesthésique local injecté après des blocs du PER chez six patients présentant des douleurs. MéTHODES: Six patients ont reçu un bloc du PER guidé par échographie du côté gauche au niveau T10. Le produit injecté contenait 29,7 mL de bupivacaïne 0,25 % et 0,3 mL de gadolinium pour le premier patient avec un supplément de 5 mL (50 mg) de triamcinolone pour les cinq patients suivants. Le bloc sensitif au toucher/piquer et au froid, ainsi que le score de douleur (où 0 indique une absence de douleur et 10, une douleur maximum) ont été évalués respectivement 20 et 30 minutes après le bloc du PER. Une IRM a été réalisée une heure après le bloc. RéSULTAT: Le produit injecté a diffusé dans l'espace intercostal et les foramens intervertébraux chez les six patients, mais l'étendue de la diffusion céphalocaudale a été variable avec une diffusion médiane [plage interquartile] de 9 [5 à 11] niveaux pour les espaces intercostaux et 3 [2 à 6] niveaux pour les foramens intervertébraux. Le produit injecté a également largement diffusé dans les muscles érecteurs du rachis. Une diffusion vers l'espace épidural a été observée chez deux patients. Un bloc sensitif des dermatomes ventraux et dorsaux a été obtenu chez tous les patients, bien que son étendue ait été variable. CONCLUSIONS: Notre étude a montré que le produit injecté dans un bloc du PER diffusait constamment dans les muscles érecteurs du rachis, les foramens intervertébraux et les espaces intercostaux. Il a été associé à des modifications sensorielles et à un soulagement de la douleur dans les parois thoraciques et abdominales, ventrales et dorsales. Néanmoins, l'étendue de la diffusion vers les foramens intervertébraux et les espaces intercostaux, ainsi que le bloc sensitif proprement dit ont été très variables.

Caracterización de mujeres colombianas con fibromialgia, comportamiento sedentario y niveles de aptitud física / Characterization of Colombian women with fibromyalgia, sedentary behavior and fitness levels

Introducción. La fibromialgia es un síndrome que se caracteriza por la presencia de dolor musculoesquelético persistente y generalizado asociado a síntomas clínicos como fatiga, trastornos del sueño, estado de ánimo depresivo, limitación funcional y disminución de la calidad de vida. Objetivo. Caracterizar el nivel de actividad física y las cualidades de la aptitud física de un grupo de mujeres colombianas con fibromialgia;. Conocer y entender estos parámetros es de interés clínico y de salud pública. Métodos. Estudio transversal descriptivo en 22 mujeres adscritas a un programa de rehabilitación, las principales medidas de resultado fueron: nivel autoinformado de actividad física, composición corporal por bioimpedancia eléctrica, capacidad cardiorrespiratoria cuantificada por caminata de seis minutos y medición de la fuerza isométrica de agarre en mano. Resultados. El grupo poblacional presenta un comportamiento predominantemente sedentario, una composición corporal con exceso de peso graso y disminución del porcentaje muscular. Lo anterior asociado a reducciones en la capacidad aeróbica y en la fuerza de agarre. Conclusión. Las pacientes con fibromialgia se caracterizan por un comportamiento sedentario y baja condición física; esta información puede ser tenida en cuenta por los profesionales de la salud en el momento del abordaje y diseño de intervenciones terapéuticas cuyo propósito sea mejorar el estado de salud y la calidad de vida de las pacientes.

Introduction. Fibromyalgia is a syndrome characterized by the presence of persistent and widespread musculoskeletal pain associated with clinical symptoms such as fatigue, sleep disturbances, depressive mood, functional limitation and decreased quality of life. Objective. To characterize the level of physical activity and physical fitness qualities of a group of Colombian women with fibromyalgia. To know and understand these parameters is of clinical and public health interest. Methods. A descriptive cross-sectional study in 22 women enrolled in a rehabilitation program, the main outcome measures were: self-reported level of physical activity, body composition by electrical bioimpedance, cardiorespiratory capacity quantified by six-minute walk and measurement of isometric hand grip strength. Results. The population group presented a predominantly sedentary behavior, a body composition with excess fat weight and a decrease in muscle percentage. This was associated with reductions in aerobic capacity and grip strength. Conclusion. Patients with fibromyalgia are characterized by sedentary behavior and low physical condition; this information can be taken into account by health professionals when approaching and designing therapeutic interventions whose purpose is to improve the health status and quality of life of patients.

Author Correction: Inference of ecological and social drivers of human brain-size evolution.

In the Acknowledgements section of this Letter, the words "M.G.-F. was funded by a Marie Sklodowska-Curie Individual Fellowship (No 701464)" should have read "This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 701464". This error has been corrected online.