Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of abdominal wall, paraspinal, and chest wall blocks.

BACKGROUND: There is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques. METHODS: We conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement. RESULTS: Sixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified. CONCLUSIONS: Harmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice.

An update to Hippocampome.org by integrating single-cell phenotypes with circuit function in vivo.

Understanding brain operation demands linking basic behavioral traits to cell-type specific dynamics of different brain-wide subcircuits. This requires a system to classify the basic operational modes of neurons and circuits. Single-cell phenotyping of firing behavior during ongoing oscillations in vivo has provided a large body of evidence on entorhinal-hippocampal function, but data are dispersed and diverse. Here, we mined literature to search for information regarding the phase-timing dynamics of over 100 hippocampal/entorhinal neuron types defined in Hippocampome.org. We identified missing and unresolved pieces of knowledge (e.g., the preferred theta phase for a specific neuron type) and complemented the dataset with our own new data. By confronting the effect of brain state and recording methods, we highlight the equivalences and differences across conditions and offer a number of novel observations. We show how a heuristic approach based on oscillatory features of morphologically identified neurons can aid in classifying extracellular recordings of single cells and discuss future opportunities and challenges towards integrating single-cell phenotypes with circuit function.

Multimodal determinants of phase-locked dynamics across deep-superficial hippocampal sublayers during theta oscillations.

Theta oscillations play a major role in temporarily defining the hippocampal rate code by translating behavioral sequences into neuronal representations. However, mechanisms constraining phase timing and cell-type-specific phase preference are unknown. Here, we employ computational models tuned with evolutionary algorithms to evaluate phase preference of individual CA1 pyramidal cells recorded in mice and rats not engaged in any particular memory task. We applied unbiased and hypothesis-free approaches to identify effects of intrinsic and synaptic factors, as well as cell morphology, in determining phase preference. We found that perisomatic inhibition delivered by complementary populations of basket cells interacts with input pathways to shape phase-locked specificity of deep and superficial pyramidal cells. Somatodendritic integration of fluctuating glutamatergic inputs defined cycle-by-cycle by unsupervised methods demonstrated that firing selection is tuneable across sublayers. Our data identify different mechanisms of phase-locking selectivity that are instrumental for flexible dynamical representations of theta sequences.

Ultrasound-Guided Pudendal Nerve Block at the Entrance of the Pudendal (Alcock) Canal: Description of Anatomy and Clinical Technique.

BACKGROUND AND OBJECTIVES: Ultrasound-guided techniques for pudendal nerve block have been described at the level of the ischial spine and transperineally. Theoretically, however, blockade of the pudendal nerve inside Alcock canal with a small local anesthetic volume would minimize the risk of sacral plexus blockade and would anesthetize all 3 branches of the pudendal nerve before they ramify in the ischioanal fossa. This technical report describes a new ultrasound-guided technique to block the pudendal nerve. The technique indicates an easy and effective roadmap to target the pudendal nerve inside the Alcock canal by following the margin of the hip bone sonographically along the greater sciatic notch, the ischial spine, and the lesser sciatic notch. METHODS: The technique was applied bilaterally in 3 patients with chronic perineal pain. The technique described was also used to locate the pudendal nerve within Alcock canal and inject dye bilaterally in 2 cadavers. RESULTS: Complete pinprick anesthesia was obtained in the pudendal territory of the perineum in all 3 patients. Pain was effectively alleviated or reduced in all patients with no affection of the sacral plexus nerve branches. In the 2 cadavers, all 4 pudendal nerves were successfully targeted and colored. CONCLUSIONS: This new technique is based on easily recognizable sonoanatomical patterns. It probably implies no risk of sacral plexus blockade, and the pudendal nerve is anesthetized before any branches ramify from the main trunk. This promising new technique must be validated in future clinical trials.