ABSTRACT
OBJECTIVE: There are no reports from Japan showing the effects of using the thromboelastography algorithm on transfusion requirements after Intensive Care Unit (ICU) admission, and post-implementation knowledge regarding the thromboelastography algorithm under the Japanese healthcare system is insufficient. Therefore, this study aimed to clarify the effect of the TEG6s thromboelastography algorithm on transfusion requirements for patients in the ICU after cardiac surgery. METHODS: We retrospectively compared the requirements for blood transfusion up to 24 h after ICU admission using the thromboelastography algorithm (January 2021 to April 2022) (thromboelastography group; n = 201) and specialist consultation with surgeons and anesthesiologists (January 2018 to December 2020) (non-thromboelastography group; n = 494). RESULTS: There were no significant between-group differences in terms of age, height, weight, body mass index, operative procedure, duration of surgery or cardiopulmonary bypass, body temperature, or urine volume during surgical intervention. Moreover, there was no significant between-group difference in the amount of drainage at 24 h after ICU admission. However, crystalloid and urine volumes were significantly higher in the thromboelastography group than in the non-thromboelastography group. Additionally, fresh-frozen plasma (FFP) transfusion volumes were significantly lower in the thromboelastography group. However, there were no significant between-group differences in red blood cell count or platelet transfusion volume. After variable adjustment, the amount of FFP used from the operating room to 24 h after ICU admission was significantly reduced in the thromboelastography group. CONCLUSIONS: The thromboelastography algorithm optimized transfusion requirements at 24 h after admission to the ICU following cardiac surgery.
Subject(s)
Cardiac Surgical Procedures , Thrombelastography , Humans , Thrombelastography/methods , Retrospective Studies , Blood Transfusion/methods , Cardiac Surgical Procedures/adverse effects , Cardiac Surgical Procedures/methods , Intensive Care Units , ProbabilityABSTRACT
The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science-policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science-policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science-policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.
ABSTRACT
Radionuclides produced by 20th-century human nuclear activities from 1945 (e.g., atmospheric nuclear explosions and nuclear-fuel reprocessing) made significant impacts on earth's surface environments. Long-lived shallow-water corals living in tropical/subtropical seas incorporate the anthropogenically-produced radionuclides, including 129I and 14C, into their skeletons, and provide time series records of the impacts of nuclear activities. Here, we present 129I/127I and Δ14C time series records of an annually-banded modern coral skeleton from Rowley Shoals, off the northwestern coast of Australia, in the far eastern Indian Ocean. The 129I/127I and Δ14C records, covering the period 1930s-1990s, exhibit distinct increases caused by the nuclear activities, and their increasing profiles are clearly different from each other. The first distinct 129I/127I increase occurs from 1955 to 1959, followed by a decrease in 1960-1963. The increase is probably due to US atmospheric nuclear explosions in Bikini and Eniwetok Atolls in 1954, 1956 and 1958. The 129I produced in those nuclear tests would be transported by the North Equatorial Current, a portion of which passes through the Indonesian Throughflow and then reaches Rowley Shoals. This initial increase from 1955 is, however, absent in the Δ14C record, which shows a distinct increase from 1959 and its peak around the mid-1970s, followed by a gradual decrease. This absence and the 4-year-delayed Δ14C increase are likely due to dilution of explosion-produced 14C with natural carbon (by seawater mixing and air-sea gas exchange) being much more intense than that of explosion-produced 129I with natural iodine (by the same processes), suggesting that the 129I/127I ratio is a more conservative anthropogenic tracer in surface ocean waters, as compared to Δ14C. The second 129I/127I increase is contemporaneous with a rapid Δ14C increase during 1964-1967, followed by a rapid 129I/127I decrease in 1968-1969; the increases can be ascribed to very large atmospheric nuclear explosions conducted in the former Soviet Union in 1961-1962. The third 129I/127I increase appears between 1969/1970 and 1992, which can be attributed to airborne 129I released from nuclear-fuel reprocessing facilities in Europe, the former Soviet Union and the US. The coral 129I/127I and Δ14C time series records, combined with previous studies, enhance our understanding of the behavior of anthropogenic 129I and 14C in the global ocean and atmosphere.
Subject(s)
Anthozoa , Radiation Monitoring , Animals , Atmosphere , Australia , Europe , Humans , Indian Ocean , Indonesia , Iodine Radioisotopes , Seawater , USSRABSTRACT
Diphenylarsinic acid (DPAA), an artificial phenyl arsenic compound, is considered a groundwater pollutant in Japan. Previous human and animal studies suggested that DPAA affects the central nervous system; however, these effects are poorly understood. The present study investigated the toxicokinetic characteristics and effects of DPAA on dopamine (DA) in the striatum of free-moving mice after a single oral administration. In a simultaneous blood and brain microdialysis study, only DPAA was detectable in both blood and striatum dialysate samples immediately after DPAA administration. DPAA concentrations in the striatum and blood dialysate rapidly reached a maximum, then decreased over time in an essentially parallel manner. A more detailed brain microdialysis examination of intracerebral kinetics revealed that the concentration of DPAA in the striatum dialysate began to increase within 15 min, reaching a maximum approximately 1 h after administration, and then decreased with a biological half-life of approximately 2 h. Moreover, a single oral administration of DPAA at 0.5-32 mg/kg affected the extracellular DA level in the striatum. The effect on DA level changed slowly after DPAA administration, with a bell-shaped dose-response relationship. The present study suggests that DPAA is rapidly absorbed into the blood circulating in the gastrointestinal tract and passes through the blood-brain barrier to subsequently affect DA levels in the striatum in mice after a single oral administration.
Subject(s)
Arsenicals/adverse effects , Corpus Striatum/drug effects , Dopamine/metabolism , Dopaminergic Neurons/drug effects , Administration, Oral , Animals , Arsenicals/administration & dosage , Arsenicals/blood , Arsenicals/pharmacokinetics , Blood-Brain Barrier/metabolism , Corpus Striatum/metabolism , Dopaminergic Neurons/metabolism , Dose-Response Relationship, Drug , Male , Mice, Inbred ICR , Microdialysis , Permeability , ToxicokineticsABSTRACT
Neurotoxic chemicals that pass through the blood-brain barrier (BBB) can influence brain function. Efficient methods to test the permeability of the BBB to specific chemicals would facilitate identification of potentially neurotoxic agents. We report here a simultaneous blood and brain microdialysis in a free-moving mouse to test BBB permeability of different chemicals. Microdialysis sampling was conducted in mice at 3-5 days after implantation of a brain microdialysis probe and 1 day after implantation of a blood microdialysis probe. Therefore, mice were under almost physiological conditions. Results of an intravenous injection of lucifer yellow or uranine showed that the BBB was functioning in the mice under the experimental conditions. Mice were given phenyl arsenic compounds orally, and concentration-time profiles for phenyl arsenic compounds such as diphenylarsinic acid, phenylarsonic acid, and phenylmethylarsinic acid in the blood and brain dialysate samples were obtained using simultaneous blood and brain microdialysis coupled with liquid chromatography-tandem mass spectrometry. Peak area-time profiles for linalool and 2-phenethyl alcohol (fragrance compounds or plant-derived volatile organic chemicals) were obtained using simultaneous blood and brain microdialysis coupled with gas chromatography-mass spectrometry in mice given lavender or rose essential oils intraperitoneally. BBB function was confirmed using lucifer yellow in these mice, and results indicated that the phenyl arsenic compounds, linalool and 2-phenethyl alcohol, passed through the BBB. The present study demonstrates that simultaneous blood and brain microdialysis in a free-moving mouse makes it possible to test the BBB permeability of chemicals when coupled with appropriate chemical analysis methods.
ABSTRACT
BACKGROUND: The costotransverse foramen (CTF) is a space continuous with the paravertebral space. We hypothesized that injections passing through the CTF will result in a successful injectate spread to the paravertebral space. OBJECTIVES: We investigated patterns of dye spread to assess characteristics of neural blockade following ultrasound-guided CTF and erector spinae plane (ESP) injection in an anatomic and clinical study. STUDY DESIGN: Prospective cadaveric study, and case studies. SETTING: University hospital. METHODS: Six soft cadavers were studied. The boundaries of the CTF and the needle pathway of CTF injection were identified in the first cadaver. The CTF and ESP injections were performed on either the left or right sides of the T4 vertebral level in cadavers 2 to 6. Fifteen milliliters of 0.2% methylene blue was injected in each block, and the spread of dye was assessed by anatomic dissection. We also report 2 case studies of CTF and ESP blocks. RESULTS: Cadaver studies of CTF injection demonstrate that with injection to the inferior aspect of the base of the transverse process, the dye mainly passes anteriorly through the CTF into the paravertebral space, with minimal track-back to the deep back muscles. Consistent sensory blockade was achieved in 2 case studies. With the ESP injection, the spread of dye was observed cephalocaudad to the fascia of the erector spinae muscle, with no dye spreading within the paravertebral space in all cadavers. LIMITATIONS: Prospective case series. CONCLUSIONS: CTF block was consistently associated with a mainly anterior spread of injectate into the paravertebral space that involved the thoracic spinal nerves, and minimal posterior spread of injectate to the deep back muscles. KEY WORDS: Thoracic vertebrae, rib cage, paraspinal muscle, nerve block, joints.
Subject(s)
Nerve Block/methods , Paraspinal Muscles , Spinal Nerves , Thoracic Vertebrae , Ultrasonography, Interventional/methods , Cadaver , Female , Humans , Injections , Male , Paraspinal Muscles/drug effects , Paraspinal Muscles/innervation , Spinal Nerves/anatomy & histology , Spinal Nerves/drug effects , Thoracic Vertebrae/anatomy & histology , Thoracic Vertebrae/drug effectsABSTRACT
BACKGROUND: Several approaches have been proposed for ultrasound-guided thoracic paravertebral block, but the best approach remains unclear. OBJECTIVE: We compared two ultrasound-guided in-plane approaches using a microconvex probe, transverse and parasagittal. We assessed whether either approach would facilitate successful catheter placement in the paravertebral space. DESIGN: Randomised controlled trial. SETTING: University hospital, July 2015 to March 2016. PATIENTS: Sixty patients scheduled to undergo thoracotomy were randomly allocated into two groups. INTERVENTIONS: A microconvex probe was placed transversely between adjacent ribs (transverse) or sagittally between adjacent transverse processes (parasagittal). When the Tuohy needle reached the paravertebral space, a catheter was inserted to a depth of 4âcm. Then, 0.5-ml radiocontrast was injected through the catheter under fluoroscopy. MAIN OUTCOME MEASURES: The primary outcome was successful catheter placement in the paravertebral space; secondary outcomes were 0 to 100âmm visual analogue scale pain score and morphine consumption in the first 24âh. RESULTS: All patients received the allocated paravertebral block. Correct catheter placement occurred in 23 (77%) and 24 patients (80%) using the transverse (n=30) and parasagittal approaches (n=30), respectively (Pâ=â1.00). Five patients were excluded due to changes in surgical procedure. Postoperative pain, represented by median [IQR] visual analogue scale score, was 19.5 [12 to 25] at rest and 55 [44 to 77] on movement with the transverse approach (n=28) vs. 22 [12 to 33.5] at rest and 59 [41.5 to 75] on movement with the parasagittal approach (n=27) (Pâ=â0.57 at rest, Pâ=â0.76 on movement). Median morphine consumption was 11.5 [5 to 21] and 11 [5 to 18]âmg in the transverse and parasagittal approaches, respectively (Pâ=â0.99). CONCLUSION: There were no clinically significant differences between approaches for continuous ultrasound-guided thoracic paravertebral block using a microconvex probe, and both approaches achieved a high rate of correct catheter placement. TRIAL REGISTRATION: UMIN Clinical Trials Registry identifier: UMIN000015988.
Subject(s)
Nerve Block , Ultrasonography, Interventional , Catheters , Humans , Pain, Postoperative/diagnosis , Pain, Postoperative/etiology , Pain, Postoperative/prevention & control , UltrasonographyABSTRACT
Thoracic wall nerve blocks reduce postoperative acute pain after breast cancer surgery (BCS); however, their short-term effects and the most effective technique remain unclear. To compare the effects of pectoral nerve block type-2 (Pecs II block) and serratus plane block for postoperative short-term analgesia, we retrospectively reviewed 43 BCS patients who underwent Pecs II block (n=22) or serratus plane block (n=21). The primary outcome was the proportion of patients with no complaints of pain 2 months post-BCS. The odds ratio (OR) was assessed, adjusting for axillary lymph node dissection. The secondary outcomes were pain severity 24 hours and 2 months post-operation using the numerical rating scale score, and morphine consumption within 24 hours. The proportion of patients without pain 2 months post-BCS was significantly less with Pecs II block than in patients with serratus plane block (55% vs. 19%, adjusted OR, 5.04; 95% confidence interval, 1.26-20.07; P=0.02); the median [interquartile range] score for pain 2 months post-operation was also significantly lower with Pecs II block (Pecs II block 0.5 [0-1] vs. serratus plane block 1 [1-2]); P=0.03). Regarding post-BCS acute analgesia, the median [interquartile range] postoperative 24-hour pain score was 2 [1-3] and 3 [1.5-3.5], and the median morphine consumption within 24 hours was 1.5 [0.75-5.5] and 3 [1.5-10] mg in Pecs II block and serratus plane block (P=0.47 and P=0.11), respectively. This study suggests that Pecs II block prevents short-term post-BCS pain better than serratus plane block. However, further studies are needed in order to support this finding.
Subject(s)
Breast Neoplasms/surgery , Mastectomy , Nerve Block/methods , Pain Management/methods , Pain, Postoperative/prevention & control , Thoracic Nerves , Adult , Aged , Female , Humans , Mastectomy/adverse effects , Middle Aged , Nerve Block/adverse effects , Pain Management/adverse effects , Pain, Postoperative/diagnosis , Pain, Postoperative/etiology , Retrospective Studies , Treatment OutcomeABSTRACT
PURPOSE: Thoracic paravertebral block (TPVB) provides a unilateral nerve block at multiple intercostal levels allowing injection of a local anesthetic into paravertebral space (PVS) via a needle or catheter. However, the most effective injection method remains unclear. This study compared the real-time spread of ropivacaine between two paravertebral injection methods using thoracoscopy. METHODS: Thirty-four patients scheduled for thoracoscopic surgery were randomly allocated into the Needle or Catheter groups, and performed transverse in-plane ultrasound-guided TPVB. The Needle group received 20 ml of 0.5% ropivacaine via a needle placed into the lateral edge of PVS; the Catheter group received the same dose of ropivacaine via a catheter inserted 5 cm into PVS. The primary outcome was the spreading pattern of ropivacaine in each group. The secondary outcome was intraoperative vasopressor requirement after paravertebral injection. RESULTS: In the Needle group, all cases showed ropivacaine spread to multiple intercostal levels, mainly across the ribs. Contrastingly, the Catheter group showed variable spreading patterns; multiple intercostal levels (n = 10) [across the ribs (n = 4), anterolateral aspect of the vertebral bodies (n = 6)] or unobservable spreading (no change; n = 7) (P = 0.007). Vasopressors were required in two and ten cases in the Needle and Catheter groups, respectively (P = 0.010). CONCLUSION: Paravertebral injection via a needle typically resulted in spreading to multiple intercostal levels, especially across the ribs on the peripheral side of injection site, whereas injection via a catheter resulted in variable spreading patterns. Therefore, injections via needles are more stable.
Subject(s)
Needles , Nerve Block , Anesthetics, Local , Catheters , Humans , Pain, Postoperative , Spine , Ultrasonography, InterventionalABSTRACT
The 28,000-year-old remains of a woolly mammoth, named 'Yuka', were found in Siberian permafrost. Here we recovered the less-damaged nucleus-like structures from the remains and visualised their dynamics in living mouse oocytes after nuclear transfer. Proteomic analyses demonstrated the presence of nuclear components in the remains. Nucleus-like structures found in the tissue homogenate were histone- and lamin-positive by immunostaining. In the reconstructed oocytes, the mammoth nuclei showed the spindle assembly, histone incorporation and partial nuclear formation; however, the full activation of nuclei for cleavage was not confirmed. DNA damage levels, which varied among the nuclei, were comparable to those of frozen-thawed mouse sperm and were reduced in some reconstructed oocytes. Our work provides a platform to evaluate the biological activities of nuclei in extinct animal species.
Subject(s)
Cell Nucleus/metabolism , Fossils/diagnostic imaging , Mammoths/metabolism , Proteomics , Animals , Cell Nucleus/chemistry , Female , Male , Mammoths/genetics , Mice , Nuclear Transfer Techniques , Oocytes/metabolismABSTRACT
Acrylamide is a probable human carcinogen and known human neurotoxin that can be generated in food through heating. Using a mathematical modelling approach, our previous study estimated long-term average dietary exposure to acrylamide in the Japanese people; however, the validity of these estimates remained unknown. Here, we aimed to obtain a more accurate estimate of acrylamide exposure that would reflect the usual practice of heat processing and consumption of foods in the population. We collected duplicate diet samples and dietary records during 24 h from a group of Japanese adults. A total of 110 duplicate diet samples were analysed for acrylamide by LC-MS/MS. Data from individual dietary records were used to examine the association between dietary acrylamide exposure and consumption of selected food groups (e.g., coffee, tea, confectioneries, and vegetables prepared at high temperature [deep-frying, stir-frying, sautéing, and baking]). Of the 110 homogenised diet samples, 108 contained detectable levels of acrylamide. Dietary exposure to acrylamide ranged from 8 to 1582 ng/kg body weight (bw)/day, with the mean value of 215 ng/kg-bw/day and median value of 143 ng/kg-bw/day. This mean value was higher than the value we previously estimated for Japanese adults using a mathematical approach. Multiple linear regression analysis showed log dietary acrylamide exposure was significantly associated with consumption of coffee and vegetables prepared at high temperature during 24-hr of sampling (adj. R2 = 0.250, p < 0.001). We revealed significant difference in dietary acrylamide exposure between participants who had coffee and vegetables prepared at high temperature (median, 169 ng/kg-bw/day; range, 35-1224 ng/kg-bw/day, n = 42) and those who had none of them (median, 75 ng/kg-bw/day; range, 8-311 ng/kg-bw/day, n = 15) (Steel-Dwass test, p < 0.05).
Subject(s)
Acrylamide/analysis , Diet , Dietary Exposure , Food Contamination/analysis , Adult , Aged , Female , Healthy Volunteers , Humans , Japan , Male , Middle Aged , Vegetables/chemistry , Young AdultABSTRACT
PURPOSE: Previous work showed that 20 mL of local anesthetic (LA) did not spread into the paravertebral space (PVS) via the intramuscular quadratus lumborum block (QLBi). If spread of LA into the PVS can be achieved by increasing the total LA volume, QLBi can be more effective. We hypothesized that a larger volume of LA for the QLBi would spread into the PVS. METHODS: This crossover volunteer study included five healthy men. For comparison, both the ultrasound-guided QLB type 2 (QLB2) and QLBi were employed on opposite sides of each volunteer, and the spread of LA solution (0.7 mL/kg) mixed with contrast media in the PVS was assessed 1 h after the first injection using magnetic resonance imaging. Sensory loss was evaluated by pinprick 90 min post-injection. Each volunteer underwent both QLB types, and the same procedures were administered on opposite sides 7 days after the first experiment. RESULTS: In total, 20 QLB blocks (10 QLB2 and 10 QLBi) were performed. LA did not spread into the PVS after the QLBi. The sensory block area included the lower abdomen after the QLB2, but not after the QLBi. The sensory block area did not extend to the upper abdominal region or the midline of the lower abdomen with either block method. CONCLUSION: LA administered by the QLB2 spreads into the PVS of T10-T12, resulting in lower and lateral abdominal sensory loss. In contrast, LA administered by the QLBi does not spread into the PVS and results in only lateral abdominal sensory loss.
Subject(s)
Anesthetics, Local/administration & dosage , Nerve Block/methods , Adult , Cross-Over Studies , Humans , Injections , Magnetic Resonance Imaging , Male , Ultrasonography, Interventional , Young AdultABSTRACT
[This corrects the article DOI: 10.1155/2017/7268308.].
ABSTRACT
Organic arsenic diphenylarsinic acid (DPAA[V]) accumulates at high concentrations in the liver of primates after its subchronic administration. However, no studies on the hepatic effects of organic arsenic compounds, including DPAA(V), on primates have been reported to date. To clarify the toxicokinetics of DPAA(V) in the liver of primates, hepatic tissue specimens were collected from cynomolgus monkeys (n = 32) at 5, 29, 170, and 339 days after repeated administration of DPAA(V) for 28 days. Four histopathological changes in the specimens were observed and pathologically evaluated. Atypical ductular proliferation was found in the DPAA(V)-exposed liver throughout the period. Inflammatory cell infiltration in Glisson's capsules and lipid droplets were seen at earlier periods after administration. Conversely, inflammatory cell infiltration in liver lobules was seen later after administration. In this experiment, we did not confirm the hepatic dysfunction of DPAA(V)-exposed monkeys by blood chemistry tests. To compensate for this, we further investigated the blood from a patient who exhibited several neurological symptoms after DPAA(V) exposure. Her blood chemistry test values for aspartate transaminase, alanine transaminase, and lactate dehydrogenase were elevated, suggesting that her liver may have been damaged by DPAA(V) exposure. Together, these findings suggest that the accumulation of DPAA(V) may induce differential histopathological changes in primate hepatocytes, resulting in decreased liver function. This is the first report to investigate the liver of primates pathologically after exposure to organic arsenic DPAA(V). Our findings will help expand our knowledge regarding the effect of DPAA(V) on the liver of primates.
Subject(s)
Arsenicals/adverse effects , Liver/drug effects , Liver/pathology , Alanine Transaminase/blood , Animals , Arsenicals/administration & dosage , Arsenicals/pharmacokinetics , Aspartate Aminotransferases/blood , Biomarkers/blood , Chemical and Drug Induced Liver Injury/diagnosis , Child , Female , Humans , Lipid Droplets/metabolism , Liver/metabolism , Liver Diseases/diagnosis , Macaca fascicularis , Time FactorsABSTRACT
BACKGROUND AND OBJECTIVES: We aimed to describe a novel technique of ultrasound-guided selective mandibular nerve block with a lateral pterygoid plate (LPP) approach and to assess its feasibility and accuracy in a soft cadaver model. METHODS: Ten soft cadavers were studied. A curved array ultrasound transducer was applied over 1 side of the face of the cadaver, in an open-mouth position. The transducer was placed transversely below the zygomatic arch and tilted in the caudal-to-cranial direction to identify the boundary of the LPP. The needle was inserted in-plane, in an anterior-to-posterior direction, into the posterior border of the uppermost part of the LPP, and 3 mL of methylene blue was injected. RESULTS: Mandibular nerve block was successfully performed in all 10 cadavers using an LPP approach under ultrasound guidance. The mandibular nerve and its branches were seen to be stained with methylene blue in all cadaveric specimens. No accidental injection into the facial nerve or maxillary artery was observed. CONCLUSIONS: This cadaveric study suggests that this novel technique, using an LPP approach under ultrasound guidance, is helpful for selective mandibular nerve block, with high accuracy and feasibility. Further studies are required to establish its safety and efficacy for clinical application. CLINICAL TRIAL REGISTRATION: This study was registered at the Thai Clinical Trials Registry (ClinicalTrials.in.th), identifier TCTR20160601004.
Subject(s)
Autonomic Nerve Block/methods , Mandibular Nerve/diagnostic imaging , Pterygoid Muscles/diagnostic imaging , Ultrasonography, Interventional/methods , Cadaver , Female , Humans , Male , Mandibular Nerve/drug effects , Methylene Blue/administration & dosage , Pterygoid Muscles/drug effects , Pterygoid Muscles/innervationABSTRACT
BACKGROUND AND OBJECTIVES: This study aimed to describe and assess the accuracy and feasibility of a novel technique for ultrasound-guided maxillary nerve block using the lateral pterygoid plate (LPP) approach via the pterygopalatine fossa (PPF) in a soft cadaveric model. METHODS: Ten soft cadavers were studied. The curved array ultrasound transducer probe was applied over 1 side of the face of the cadavers in the open-mouth posture. It was placed transversely below the zygomatic arch for identifying the border of the maxillary tuberosity and the LPP. We tilted the curve probe from the caudal to the cranial direction until the uppermost part of the PPF was identified. The in-plane needle approach was used from the anterior-to-posterior and lateral-to-medial directions through the fossa, and 3 mL of methylene blue dye was injected. RESULTS: The spread of injectate after ultrasound-guided maxillary nerve block using the LPP approach was successfully performed in all cadavers as demonstrated by visualized moderate to marked traces of methylene blue within the PPF. No accidental injections in the maxillary arteries or facial nerves were observed. CONCLUSIONS: This cadaveric study suggests that ultrasound-guided maxillary nerve block using the LPP approach via the PPF has a high degree of accuracy and feasibility. Further studies are required to confirm its efficacy and safety for clinical application.