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Introduction: Although the maxillary nerve block (MNB) provides adequate pain relief in cleft palate surgery, it is not routinely used globally, and reported techniques are heterogeneous. This study aims to describe relevant anatomy and to present the preferred technique of MNB administration based on the current literature and the expert opinion of the authors., Method and Materials: First, a survey was sent to 432 registrants of the International Cleft Palate Master Course Amsterdam 2023. Second, MEDLINE (PubMed interface) was searched for relevant literature on maxillary artery (MA) anatomy and MNB administration in pediatric patients., Results: Survey response rate was 18% (n=78). Thirty-five respondents (44.9%) used MNB for cleft palate surgery before the course. A suprazygomatic approach with needle reorientation towards the ipsilateral commissure before incision was most frequently reported, mostly without the use of ultrasound. Ten and 20 articles were included on, respectively, MA anatomy and MNB administration. A 47.5% to 69.4% of the MA's run superficial to the lateral pterygoid muscle and 32% to 52.5% medially. The most frequently described technique for MNB administration is the suprazygomatic approach. Reorientation of the needle towards the anterior aspect of the contralateral tragus appears optimal. Needle reorientation angles do not have to be adjusted for age, unlike needle depth. The preferred anesthetics are either ropivacaine or (levo)bupivacaine, with dexmedetomidine as an adjuvant., Conclusion: Described MNB techniques are heterogeneous throughout the literature and among survey respondents and not routinely used. Further research is required comparing different techniques regarding efficacy and safety., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of Mutaz B. Habal, MD.)

Purpose of Review: Ultrasound-guided regional anesthesia is a challenging, complex skill and requires competence in teaching. The aim of this study was to review current literature on identification of education and learning of ultrasound-guided regional anesthesia and to summarize recent findings on teaching concepts., Recent Findings: Several teaching programs have been described and implemented into daily routine. Factors relevant to current practice are the knowledge of sonoanatomy, the acquisition of manual skills, the teaching ability, and the feedback given to the trainee. Simulation is a rapidly growing field and is supported by the development of phantoms. Needle visualization is one of the core competencies that is necessary for successful ultrasound-guided procedures and could be supported by technical developments in the future to improve teaching concepts., Summary: Although a lot of key questions cannot be answered by the latest study results, some interesting findings were able to improve existing education programs. These results should be tailored to the individual need of a trainee, and the effects of improved training programs on patient safety and quality of care have to be investigated. The see one, do one, teach one approach is obsolete and should be abandoned.

Unlabelled: The reamer-irrigator-aspirator (RIA) is a device that has recently been developed to retrieve bone graft from the medullary canal of the femur and the tibia. As for most new surgical procedures, complications arise as part of the learning curve and/or imperfections in the design or technique. To increase awareness of potential complications and to prevent unnecessary harm to the patient, new complications need to be reported. We present case reports of 2 patients who developed severe intraoperative cardiac events presumably caused by excessive and rapid blood loss during RIA bone graft harvesting. This complication has not been described before. Increased awareness of excessive blood loss and subsequent cardiac events during an RIA procedure is warranted., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Objective: Hyperbaric oxygenation is the accepted treatment for cerebral arterial gas embolism. Although earlier start of hyperbaric oxygenation is associated with better outcome, it is unknown how much delay can be tolerated before start of hyperbaric oxygenation. This study investigates the effect of hyperbaric oxygenation on cerebral function in swine when initiated 2 or 4 hours after cerebral arterial gas embolism., Design: Prospective interventional animal study., Setting: Surgical laboratory and hyperbaric chamber., Subjects: Twenty-two Landrace pigs., Interventions: Under general anesthesia, probes to measure intracranial pressure, brain oxygen tension (PbtO2), and brain microdialysis, and electrodes for electroencephalography were placed. The electroencephalogram (quantified using temporal brain symmetry index) was suppressed during 1 hour by repeated injection of air boluses through a catheter placed in the right ascending pharyngeal artery. Hyperbaric oxygenation was administered using U.S. Navy Treatment Table 6 after 2- or 4-hour delay. Control animals were maintained on an inspiratory oxygen fraction of 0.4., Measurements and Main Results: Intracranial pressure increased to a mean maximum of 19 mm Hg (SD, 4.5 mm Hg) due to the embolization procedure. Hyperbaric oxygenation significantly increased PbtO2 in both groups treated with hyperbaric oxygenation (mean maximum PbtO2, 390 torr; SD, 177 torr). There were no significant differences between groups with regard to temporal brain symmetry index (control vs 2-hr delay, p = 0.078; control vs 4-hr delay, p = 0.150), intracranial pressure, and microdialysis values., Conclusions: We did not observe an effect of hyperbaric oxygenation on cerebral function after a delay of 2 or 4 hours. The injury caused in our model could be too severe for a single session of hyperbaric oxygenation to be effective. Our study should not change current hyperbaric oxygenation strategies for cerebral arterial gas embolism, but further research is necessary to elucidate our results. Whether less severe injury benefits from hyperbaric oxygenation should be investigated in models using smaller amounts of air and clinical outcome measures.

Introduction: Ketamine has been demonstrated to be neurotoxic in animals as well as in patients. Preservatives added to ketamine have been accused to induce this neurotoxicity. Therefore, we investigated whether the most widely used preservative of ketamine-benzethonium chloride-enhances the toxicity of S(+)-ketamine in vitro in lymphoma, neuroblastoma cells and primary astrocytes., Methods: Human Jurkat T-lymphoma- and neuroblastoma cells (SHEP) were incubated for 24 hours with commercially available S-ketamine containing benzethonium, pure S-ketamine and pure benzethonium chloride. The rate of early- and late-apoptotic cells was evaluated by flowcytometry. In a second step the combined toxicity of benzethonium and ketamine was investigated in neuroblastoma cells and primary rat astrocytes in a mitochondrial activity assay (XTT). The additivity of the toxicities was evaluated by employing isobolographic analysis., Results: In Jurkat T-lymphoma and neuroblastoma cells benzethonium increased the toxicity of ketamine from 32% to 80% and from 64% to 84% cell deaths, respectively. In neuroblastoma cells as well as in primary rat astrocytes the measured combined toxicity was within the confidence interval of the calculated pure additive toxicity as seen in the isobolograms., Conclusions: We conclude that benzethonium increases the local toxicity of ketamine in cells of hematopoietic, neuronal and glial origin in an additive manner. Therefore, caution is recommended especially when using preservative containing S-ketamine as an additive for long-term neuraxial analgesia.

Background: Local anesthetics, especially lidocaine, can lead to persistent cauda equina syndrome after spinal anesthesia. Recently, lidocaine has been reported to trigger apoptosis, although the underlying mechanisms remain unknown. To elucidate the pathway of lidocaine-induced apoptosis, the authors used genetically modified cells with overexpression or deficiencies of key regulators of apoptosis., Methods: Human Jurkat T-lymphoma cells overexpressing the antiapoptotic protein B-cell lymphoma 2 as well as cells deficient of caspase 9, caspase 8, or Fas-associated protein with death domain were exposed to lidocaine and compared with parental cells. The authors evaluated cell viability, mitochondrial alterations, cytochrome c release, caspase activation, and early apoptosis. Apoptosis was in addition investigated in neuroblastoma cells., Results: In Jurkat cells, lidocaine reduced viability, associated with a loss of the mitochondrial membrane potential. At low concentrations (3-6 mm) of lidocaine, caspase 3 was activated and release of cytochrome c was detected, whereas at higher concentrations (10 mm), no caspase activation was found. Apoptosis by lidocaine was strongly reduced by B-cell lymphoma-2 protein overexpression or caspase-9 deficiency, whereas cells lacking the death receptor pathway components caspase 8 and Fas-associated protein with death domain were not protected and displayed similar apoptotic alterations as the parental cells. Lidocaine also induced apoptotic caspase activation in neuroblastoma cells., Conclusions: Apoptosis is triggered by concentrations of lidocaine occurring intrathecally after spinal anesthesia, whereas higher concentrations induce necrosis. The data indicate that death receptors are not involved in lidocaine-induced apoptosis. In contrast, the observation that B-cell lymphoma-2 protein overexpression or the lack of caspase 9 abolished apoptosis clearly implicates the intrinsic mitochondrial death pathway in lidocaine-induced apoptosis.

Background: In this prospective, randomized, double-blind trial we investigated the use of stimulating catheters in patients during and after shoulder surgery; functional improvement being the primary outcome measurement., Methods: After eliciting an adequate muscular twitch at < or =0.5 mA nerve stimulation output, the perineural catheter was advanced either blindly (conventional catheter = CC group, n = 20) or guided by stimulation via the catheter (stimulating catheter = SC group, n = 20). A bolus of 40 mL prilocaine 1% and 10 mL ropivacaine 0.75% was injected, followed by a patient-controlled infusion of ropivacaine 0.2% (8 mL/h infusion rate, bolus 2 mL, lockout time 20 min)., Results: Onset of motor block was faster in the SC group, whereas sensory block did not differ between groups. Median pain scores on two postoperative days were equal. Improvement of the objective shoulder function score (Constant Murley Score) 6 wk postoperatively was enhanced to a clinically relevant extent in the SC group compared to the CC group (P < 0.01)., Conclusions: We conclude that the use of a stimulating catheter results in a faster onset of motor block, unaltered postoperative pain, and a significantly improved functional outcome 6 wk after shoulder surgery.

Increase in skin temperature (Ts) occurs early during neuraxial blocks. However, the reliability of Ts to predict successful peripheral block is unknown. Therefore, we investigated whether an increase in Ts more than 1 degrees C precedes or follows an impairment of sensation after combined femoral and sciatic nerve block as well as after epidural anesthesia. In this prospective, nonrandomized study we determined Ts changes in 33 patients undergoing knee or foot surgery under femoral and sciatic nerve block and 10 patients undergoing epidural anesthesia. Perception and motor function were assessed every 5 min. An increase in Ts (> or =1 degrees C) at the foot occurred later after sciatic nerve block than after epidural anesthesia (10.3 +/- 2.8 versus 5.0 min; P < 0.01). Alterations of Ts at skin innervated by the femoral nerve were <1 degrees C. Ts increase preceded sensory block after sciatic nerve block in 6.6% of patients but indicated a successful block (sensitivity, specificity, and accuracy = 100%). We conclude that an increase of Ts is a reliable, but late, sign of successful sciatic nerve block. Therefore it is of limited clinical value. Ts changes after femoral nerve block are negligible and late.