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Objective:To compare the application value of ultrasound-guided lumbar plexus block (LPB) and continuous adductor canal nerve block (ACNB) in total hip arthroplasty (THA), and to explore the anesthesia scheme of THA.Methods:A prospective randomized controlled trial was used. Ninety patients who received THA admitted to in Lishui People′s Hospital from March 2019 to February 2022 were selected as the study subjects. According to the random number table method, 90 patients were divided into the test group and the control group, with 45 patients in each. The control group received LPB + general anesthesia, and the test group received ACNB + general anesthesia. By evaluating the hemodynamic parameters heart rate (HR) and mean arterial pressure (MAP) at the time of entry (T 1), osteotomy (T 2), prosthesis implantation (T 3) and immediately after surgery (T 4); the pain degree visual analogue score (VAS) at 6 h (S 1), 12 h (S 2), 24 h (S 3), 48 h (S 4) after awakening; the dosage of anesthetic drugs, the anesthetic effects of LPB and ACNB in THA were compared. Results:From T 2 to T 4, HR of patients in the two groups had a trend of increase: (85.24 ± 4.26) times/min vs. (86.13 ± 4.86) times/min, (83.82 ± 5.11) times/min vs. (85.16 ± 3.56) times/min and (81.64 ± 4.32) times/min vs. (82.24 ± 4.62) times/min, while MAP was in a downward trend: (86.54 ± 4.25) mmHg (1 mmHg = 0.133 kPa) vs. (85.35 ± 4.66) mmHg, (86.15 ± 3.92) mmHg vs. (84.86 ± 4.13) mmHg and (90.65 ± 5.25) mmHg vs. (92.12 ± 4.62) mmHg. The difference at different time points was statistically significant ( P<0.05). There was no statistically significant difference in HR, MAP and change trend between the two groups at different time ( P>0.05). The VAS score of the two groups increased from S 2 time point, and the difference between different time points was statistically significant ( P<0.05). The rising trend of VAS score in the test group was lower than that in the control group, and the VAS score at different time points was lower than that in the control group ( P<0.05). The dosage of sufentanil used in the test group was less than that in the control group: (114.37 ± 16.61) μg vs. (131.36 ± 18.31) μg, and the number of press of analgesia pump was less than that in the control group: 6.00 (5.00, 6.50) times vs. 8.00 (7.00, 9.00) times ( P<0.05). Conclusions:Ultrasound-guided LPB and ACNB could maintain hemodynamic stability in THA. Especially, ACNB could play an analgesic role within 48 h after THA and reduce the dosage of analgesic drugs.
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Background:Fracture femur is common in elderly. Spinal anesthesia (SA) in elderly patients can be associated with major hemodynamic changes whereas lumbar plexus block (LPB) can provide ideal perioperativeanalgesia as there is no hemodynamic instability or depression of pulmonary functions. The purpose of this study is to compare the efficacy of SA versus LPB for intraoperative anesthesia and postoperative analgesia in fracture femur surgery.Materials andMethods: This prospective randomized controlled study was carried out 70 patients of either sex with age >20 years, ASA physical status I -III scheduled for fracture femur surgery. Patients were randomly classified into two equal groups (n = 35); group I(SA) received SA by heavy bupivacaine HCL 0.5% 2.5-3.5 ml and group II (LBP) received posterior LPB by 30-35 ml bupivacaine 0.5% Results:The time for performing the block was significantly longer in group LPB than group SA. The onset of sensory and motor block was significantly increased in group LPB than group SA. The intraoperative HR was significantly increased, and intraoperative MAP was significantly decreased in group SA compared to group LPB at 5, 10, 15, 20, 25 and 30 minutes. Postoperative HR and MAP was significantly increased in group SA compared to group LPB at 1 and 6 h. Postoperative VAS was significantly increased in group SA than group LPB at 1 and 6 h. The duration of sensory and motor block was significantly increased in group LPB than group SA. The time of postoperative first analgesic requirement was significantly longer and the total pethidine consumption in the 1st24 h was significantly lower in group LPB than group SA. SA was associated with significant increase in hypotension, nausea, vomiting and headache.Conclusion:LPB is an effective alternative to SA as an anesthetic technique for femur fracture surgeries. LBP offers a more stable intraoperative hemodynamics and provides longer duration of analgesia postoperatively with less side effects. However, SA has shorter time for performing the block with earlier onset of sensory and motor block
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Abstract Background and objectives: The lumbar plexus block (LPB) is a key technique for lower limb surgery. All approaches to the LPB involve a number of complications. We hypothesized that Chayen's approach, which involves a more caudal and more lateral needle entry point than the major techniques described in the literature, would be associated with a lower rate of epidural spread. Method: We reviewed the electronic medical records and chart of all adult patients who underwent orthopedic surgery for Total Hip Arthroplasty (THA) and hip hemiarthroplasty due to osteoarthritis and femoral neck fracture with LPB and Sciatic Nerve Block (SNB) between January 1, 2002, and December 31, 2017, in our institute. The LPB was performed according to Chayen's technique using a mixture of mepivacaine and levobupivacaine (total volume, 25 mL) and a SNB by the parasacral approach. The sensory and motor block was evaluated bilaterally during intraoperative and postoperative period. Results: A total number of 700 patients with American Society of Anesthesiologists (ASA) physical status I to IV who underwent LPB met the inclusion criteria. The LPB and SNB was successfully performed in all patients. Epidural spread was reported in a single patient (0.14%;p < 0.05), accounting for an 8.30% reduction compared with the other approaches described in the literature. No other complications were recorded. Conclusions: This retrospective study indicates that more caudal and more lateral approach to the LPB, such as the Chayen's approach, is characterized by a lower epidural spread than the other approach to the LPB.
Resumo Justificativa e objetivos: O bloqueio do plexo lombar (BPL) é uma técnica fundamental para a cirurgia de membros inferiores. Todas as abordagens do BPL são associadas a uma série de complicações. Nossa hipótese foi de que a abordagem de Chayen, que envolve um ponto de entrada da agulha mais caudal e mais lateral do que as principais técnicas descritas na literatura, estaria associada a menor incidência de dispersão peridural. Método: Revisamos os prontuários médicos eletrônicos e em papel de todos os pacientes adultos submetidos à artroplastia total do quadril (ATQ) e hemiartroplastia do quadril devido a osteoartrite ou fratura do colo do fêmur empregando-se BPL associado ao bloqueio do nervo ciático (BNC), entre 1 de janeiro de 2002 e 31 de dezembro de 2017 em nossa instituição. Realizamos o BPL usando a técnica de Chayen e uma mistura de mepivacaína e levobupivacaína (volume total de 25 mL) e o BNC pela abordagem parassacral. Testes sensorial e motor bilaterais foram realizados no intra e pós-operatório. Resultados: Os critérios de inclusão foram obedecidos pelo total de 700 pacientes classe ASA I a IV submetidos ao BPL. Os BPL e BNC foram realizados com sucesso em todos os pacientes. A dispersão peridural foi relatada em um único paciente (0,14%; p < 0,05), representando uma redução de 8,30% quando comparada às outras abordagens descritas na literatura. Nenhuma outra complicação foi registrada. Conclusões: Este estudo retrospectivo indica que a abordagem mais caudal e mais lateral do BPL, como a técnica de Chayen, é caracterizada por menor dispersão peridural do que outras abordagens do BPL.
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Humanos , Masculino , Femenino , Adulto , Anciano , Anciano de 80 o más Años , Nervio Ciático , Artroplastia de Reemplazo de Cadera , Hemiartroplastia , Articulación de la Cadera/cirugía , Plexo Lumbosacro , Bloqueo Nervioso/efectos adversos , Bloqueo Nervioso/métodos , Incidencia , Estudios Retrospectivos , Espacio Epidural , Persona de Mediana EdadRESUMEN
Abstract Background Perioperative myocardial ischemia is common among patients undergoing hip fracture surgery. Our aim is to evaluate the efficacy of perioperative continuous lumbar plexus block in reducing the risk of cardiac ischemic events of elderly patients undergoing surgery for hip fractures, expressed as a reduction of ischemic events per subject. Methods Patients older than 60 years, ASA II-III, with risk factors for or known coronary artery disease were enrolled in this randomized controlled study. Patients were randomized to conventional analgesia using opioid intravenous patient-controlled analgesia or continuous lumbar plexus block analgesia, both started preoperatively and maintained until postoperative day three. Continuous electrocardiogram monitoring with ST segment analysis was recorded. Serial cardiac enzymes and pain scores were registered during the entire period. We measured the incidence of ischemic events per subject registered by a continuous ST-segment Holter monitoring. Results Thirty-one patients (intravenous patient-controlled analgesia 14, lumbar plexus 17) were enrolled. There were no major cardiac events during the observation period. The number of ischemic events recorded by subject during the observation period was 6 in the lumbar plexus group and 3 in the intravenous patient-controlled analgesia group. This difference was not statistically significant (p = 0.618). There were no statistically significant differences in the number of cases with increased perioperative troponin values (3 cases in the lumbar plexus group and 1 case in the intravenous patient-controlled analgesia group) or in terms of pain scores. Conclusions Using continuous perineural analgesia, compared with conventional systemic analgesia, does not modify the incidence of perioperative cardiac ischemic events of elderly patients with hip fracture.
Resumo Justificativa A isquemia miocárdica perioperatória é comum em pacientes submetidos à cirurgia de fratura de quadril. Nosso objetivo foi avaliar a eficácia do bloqueio perioperatório contínuo do plexo lombar na redução do risco de eventos cardíacos isquêmicos em pacientes idosos submetidos à cirurgia para fraturas de quadril, expresso como uma redução de eventos isquêmicos por indivíduo. Métodos Pacientes com mais de 60 anos de idade, ASA II-III com fatores de risco para ou com doença coronariana conhecida foram incluídos neste estudo controlado e randomizado. Os pacientes foram aleatorizados para analgesia convencional usando analgésicos opioides para administração de analgesia intravenosa controlada pelo paciente (Intravenous Patient-Controlled Analgesia - IVPCA) ou analgesia contínua com o bloqueio do Plexo Lombar (PL), ambas iniciadas no pré-operatório e mantidas até o terceiro dia de pós-operatório. Monitoração contínua de ECG com análise do segmento ST foi registrada. Enzimas cardíacas seriadas e escores de dor foram registrados durante todo o período. Medimos a incidência de eventos isquêmicos por indivíduo registrados com monitoração contínua do segmento ST via Holter. Resultados Trinta e um pacientes (IVPCA 14, PL 17) foram incluídos. Não houve eventos cardíacos sérios durante o período de observação. O número de eventos isquêmicos registrados por sujeito durante o período de observação foi de seis no grupo PL e três no grupo IVPCA. Essa diferença não foi estatisticamente significativa (p = 0,618). Não houve diferenças estatisticamente significativas no número de casos com aumento dos valores de troponina no perioperatório (três casos no grupo LP e um caso no grupo IVPCA) ou em termos de escores de dor. Conclusões O uso da analgesia perineural contínua comparado ao da analgesia sistêmica convencional não modifica a incidência de eventos isquêmicos cardíacos no período perioperatório de pacientes idosos com fratura de quadril.
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Procedimientos Quirúrgicos Cardiovasculares , Bloqueo del Plexo Cervical , Fracturas de Cadera , Analgesia/métodos , Plexo Lumbosacro/lesionesRESUMEN
Objective To observe the clinical efficacy and safety of 2 differentdoses of dexmedetomidine combined with low-concentration ropivacaine during lumbar plexus block for elderly patients. Methods Ninety elderly patients were randomly divided into group A,B and C with 30 cases in each group. All patients were performed lumbar plexus block guided by ultrasound and nerve stimulator.35 mL of 0.25% ropivacaine was injected in group A,35ml of 0.25% ropivacaine plus dexmedetomidine 0.5 μg/kg in group B,and 35 mL of 0.25% ropiva-caine plus dexmedetomidine 1 ug·kg-1in group C. Onset time,duration,blocking extent and the occurrence of adverse events wererecordedafter lumbar plexus block.Ramssay sedation score,blood pressure,heart rate and res-piration were monitored intraoperatively,and the dosage of analgesic within 24 hours after operation was measured. Results Group C witnessed the shortest onset time of sensory and motor block and the longest duration,followed by group B and A(P<0.01).The Ramssay sedation score of group C was higher than that of group A and B(P<0.05),but no significant difference was found between group A and B. Group C witnessed the lowest blood pres-sure and heart rate(P < 0.05),followed by group A and B(P < 0.05). The dosage of analgesics in group C was less than thatof group A and B(P<0.05),withthe lest in group B(P<0.05).All patients in group B and C com-pleted the surgery only under nerve blockade.However,there were6 patients in group Arequiring additional intrave-nous anesthesia to complete the surgery for poor outcome of nerve blockade. Conclusions The mixture of 0.5~1 μg·kg-1dexmedetomidine and 0.25% ropivacaine in lumbar plexus block can achieve good anesthetic outcome for elderly patients,with moderate sedation,stable respiration and circulation,and less adverse events.
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RESUMO JUSTIFICATICA E OBJETIVOS: A dor pós-operatória da artroplastia total do quadril tem intensidade moderada a intensa, exigindo a realização de técnicas analgésicas eficazes. O objetivo deste estudo foi comparar o bloqueio do plexo lombar contínuo com a analgesia peridural em pacientes submetidos à artroplastia de quadril. MÉTODOS: Estudo retrospectivo, observacional e analítico dos pacientes submetidos à artroplastia de quadril durante dois anos, sob analgesia pós-operatória por bloqueios do plexo lombar contínuo e peridural. Os pacientes foram divididos de acordo com a técnica analgésica escolhida pelo anestesiologista. O protocolo consiste em infusão contínua de ropivacaína a 0,2% (5mL/h) via cateter de bloqueio do plexo lombar contínuo ou em ropivacaína a 0,1% e fentanil 3µg/mL (5mL/h) via cateter peridural. Recorrendo aos registos da Unidade de Dor Aguda, foram comparados os três dias pós-operatórios dos grupos bloqueio do plexo lombar contínuo e peridural em relação à intensidade da dor, analgesia de resgate, complicações e tempo de internação hospitalar. RESULTADOS: Foram incluídos 162 pacientes. A maioria de ambos os grupos não apresentou queixas de dor no primeiro dia pós-operatório (77,6% bloqueio do plexo lombar contínuo versus 79,2% peridural). Ambos os grupos não diferiram em relação à intensidade de dor nem à incidência de necessidade de analgesia de resgate (23,5% bloqueio do plexo lombar contínuo versus 22,1% peridural). O grupo bloqueio do plexo lombar contínuo registrou menos complicações (4,7% versus 23,4%), nomeadamente bloqueio motor, náuseas, vômitos e prurido. A rara ocorrência de complicações não permite detectar diferenças significativas entre as técnicas. A maioria dos pacientes de ambos os grupos obteve alta hospitalar no 3º dia pós-operatório. CONCLUSÃO: Em relação à analgesia peridural, o bloqueio do plexo lombar contínuo proporcionou analgesia semelhante com menos complicações.
ABSTRACT BACKGROUND AND OBJECTIVES: Postoperative pain after total hip arthroplasty is moderate to severe and requires effective analgesic techniques. This study aimed at comparing continuous lumbar plexus block and epidural analgesia in patients submitted to hip arthroplasty. METHODS: This is a prospective, observational and analytical study of patients submitted to hip arthroplasty in a two-year period, under postoperative analgesia with continuous lumbar plexus block and epidural analgesia. Patients were divided according to the analgesic technique chosen by the anesthesiologist. The protocol consists in continuous perfusion of 0.2% ropivacaine (5mL/h) via continuous lumbar plexus block catheter or 0.1% ropivacaine and fentanil (3μg/mL) (5mL/h) via epidural catheter. Using Acute Pain Unit records, three postoperative days were compared between continuous lumbar plexus block and epidural analgesia with regard to pain intensity, rescue analgesia, complications and hospital stay. RESULTS: Participated in the study 162 patients. Most patients of both groups had no pain in the first postoperative day (77.6% continuous lumbar plexus block versus 79.2% epidural). Both groups were not different with regard to pain intensity and need for rescue analgesia (23.5% continuous lumbar plexus block versus 22.1% epidural). Continuous lumbar plexus block group had fewer complications (4.7% versus 23.4%), namely motor block, nausea, vomiting and itching. The low number of complications does not allow the detection of significant differences between techniques. Most patients of both groups were discharged in the third postoperative day. CONCLUSION: As compared to epidural analgesia, continuous lumbar plexus block has provided similar analgesia with fewer complications.
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Malignant psoas syndrome(MPS)is one of challenging cancer pain states, which is often refractory to conventional analgesic therapy. We report a case of a 67 years-old female patient suffering from left MPS caused by lumbar paravertebral malignant lymphoma. Tapentadol, a dual action analgesic, has relatively low affinity to mu-opioid receptor and provoke noradrenergic reuptake inhibition simultaneously. Neuropathic component is predominant in MPS. Tapentadol is reported to be a drug of choice for the treatment of neuropathic pain. Psoas compartment blockade is a choice of interventions to relieve severe thigh pain caused by a lesion of lumbar plexus which exists in a compartment between psoas and quadratus lumborum muscles. Pain and numbness in the affected left thigh region of the patient were well managed by opioid switching from oxycodone to tapentadol and supplemental psoas compartment blocks with a local anesthetic and dexamethasone. The activity of daily life and quality of life of the patient were dramatically improved. Tapentadol with psoas compartment blockade may be efficacious for the management of MPS.
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O bloqueio do plexo lombar (BPL) é um método adequado para uso em pacientes idosos e cirurgias na extremidade inferior. Muitas complicações podem ser observadas durante o BPL, mas não tanto quanto no bloqueio central. Neste relato de caso, nosso objetivo foi relatar uma raquianestesia total, uma complicação incomum. BPL com bloqueio ciático foi planejado para um paciente do sexo masculino, 76 anos, programado para artroplastia total do joelho por causa de gonartrose. O paciente ficou inconsciente após o bloqueio do compartimento do psoas com a técnica de Chayen para BPL. A operação terminou em 145 minutos. O paciente foi internado em unidade de terapia intensiva até o segundo dia pós-operatório e recebeu alta hospitalar no quinto dia pós-cirúrgico. A principal preocupação da monitoração do paciente deve ser a presença do anestesiologista. Dessa forma, conclui-se que o contato com o paciente deve ser garantido durante esses procedimentos.
Lumbar plexus block (LPB) is a suitable method for elder patients for lower extremity surgery. Many complications could be seen during LPB, but not as many as central block. In this case report, we aimed to report a total spinal block, an unusual complication. LPB with sciatic block was planned for a male patient, 76 years old, scheduled for total knee replacement due to gonarthrosis. The patient became unconscious after psoas compartment block with Chayen technique for LPB. The operation ended at 145th minute. The patient was admitted to intensive care unit until postoperative second day and discharged to home on fifth day of surgery. Main concern of patient monitorization should be an anesthesiologist. In this manner, we conclude that contacting to the patient should be ensured during these procedures.
El bloqueo del plexo lumbar (BPL) es un método adecuado para usarlo en pacientes ancianos sometidos a cirugía de la extremidad inferior. Durante el BPL pueden observarse muchas complicaciones, pero no tantas como en el bloqueo central. En este relato de caso, nuestro objetivo fue exponer una raquianestesia total, una complicación no común. Se planificó un BPL con bloqueo ciático para un paciente del sexo masculino, de 76 años de edad, programado para artroplastia total de la rodilla debida a gonartrosis. El paciente quedó inconsciente después del bloqueo del compartimento del psoas con la técnica de Chayen para BPL. La operación terminó en 145 min. El paciente fue ingresado en la unidad de cuidados intensivos hasta el segundo día del postoperatorio y tuvo alta hospitalaria al quinto día poscirugía. La principal preocupación de la monitorización del paciente debe ser la presencia del anestesiólogo. Así se concluye que el contacto con el paciente debe estar garantizado durante esos procedimientos.
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Anciano , Humanos , Masculino , Artroplastia de Reemplazo de Rodilla , Plexo Lumbosacro , Bloqueo NerviosoRESUMEN
Introducción: el tratamiento del dolor posoperatorio de la artroscopia de cadera es un reto y no se conocen estudios relacionados con su tratamiento basado en bloqueos regionales. Objetivo: Determinar el comportamiento del dolor posoperatorio y la satisfacción de los pacientes tratados por artroscopia de cadera con bloqueo femoral, bloqueo del plexo lumbar o infiltración intraarticular. Métodos: Se revisaron prospectivamente todos los registros anestésicos de 61 pacientes que requirieron artroscopia de cadera bajo anestesia general utilizando bloqueo femoral con 0,3 mL/kg de levobupivacaína al 0,375 %, bloqueo del plexo lumbar con 0,4 mL/kg de levobupivacaína al 0,375 % o infiltración intraarticular con 20 mL de bupivacaína al 0,5 %. Se revisaron los datos de dolor posoperatorio evaluados con escala visual análoga a los 15, 30, 60 y 120 minutos y a las 24 horas; la satisfacción del paciente en el momento del alta hospitalaria y a las 24 horas, el bloqueo motor y sensitivo y la necesidad de morfina en el posoperatorio. Resultados: El grupo tratado con infiltración intraarticular presentó los niveles de dolor más altos en casi todos los momentos evaluados. Comparado con el bloqueo del plexo lumbar, más pacientes del grupo bloqueo femoral presentaron niveles mayores de dolor en casi todos los momentos. De los pacientes del grupo tratado con infiltración intraarticular 55 % recibieron morfina en algún momento del posoperatorio, así como 28,5 % del grupo bloqueo femoral y 15 % del grupo bloqueo del plexo lumbar. El nivel de satisfacción de los pacientes fue alto y similar en los tres grupos. Conclusión: La analgesia posoperatoria para artroscopia de cadera fue mejor con bloqueo del plexo lumbar comparado con el bloqueo femoral o la infiltración intraarticular.
Background: The treatment of postoperative pain after arthroscopy of the hip is a challenge and there are no known studies related to its treatment which have been based on regional block. Objectives:To determine the behaviour of postoperative pain and the satisfaction of the patients who have been treated with arthroscopy of the hip with femoral block, lumbar plexus block or intra-articular infiltration. Methods:All the anaesthetic records of 61 patients that required arthroscopy of the hip under general anaesthesia using femoral block with 0,3 mL/kg of Levobupivacaine 0,375 %, lumbar plexus block with 0,4 mL/kg of Levobupivacaine 0,375 % or intra-articular infiltration with 20 mL of Bupivacaine 0,5 % were checked. The data about postoperative pain which had been assessed with visual analogous scale at the 15, 30, 60 and 120 minutes and at the 24 hours, the satisfaction of the patients at the moment of the discharge from hospital at the 24 hours, the sensitive and motor block and the need to use Morphine in the postoperative phase were also checked. Results:The group of patients that were treated with intra-articular infiltration presented the highest levels of pain in almost all evaluated moments. As compared with the lumbar plexus block, more patients that underwent femoral block presented higher levels of pain in almost all moments. Out of the patients in the group that was treated with intra-articular infiltration, the 55 % received Morphine at any postoperative moment as well as the 28,5 % treated with femoral block and the 15 % who underwent lumbar plexus block. The level of patients´ satisfaction was high and similar in the three groups. Conclusions:Postoperative analgesia for arthroscopy of the hip was better with lumbar plexus block as compared with femoral block or intra-articular infiltration.
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Objective To evaluate the effect of dexamethasone on lumbar plexus combined sciatic nerve block (CLPSNB). Methods Sixty patients were randomly allocated into three groups with 20 cases each. Guided by a nerve stimulator,CLPSNB was performed with 0. 5% ropivacaine 45 ml plus dexametbasone 10 mg in group A,0. 5% ropivacaine 45 ml plus normal saline(NS) 2 ml and dexametbasone 10 rng Ⅳ. in group B,or 0. 5% ropivacaine 45 ml plus NS 2 ml in group C. ResultsThe durations of sensory and motor blockade in group A were [(15. 2 ± 3. 3)h and (12. 6 ± 2. 8)h], respectively, which were significantly longer than [(10. 1 ± 2. 1)h and (7. 9 ± 1.6)h]in group B and [(10. 4±2. 5)h and (7. 6±2. 3)hi in group C(P<0. 05). Conclusion Dexarnetbasone added to 0. 5% ropivacaine significantly prolonges CLPSNB.
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0.1), but duration of sensory and motor block in S group was longer than that in C group (P
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BACKGROUND: Lumbar plexus block was used not only for the proposal of lower limb surgery, but also for that of pain control in the pain clinic. The aim of our study was to evaluate the motor, sensory function and the anatomic parameters after posterior approach of the lumbar plexus block with the help of a nerve stimulator. METHODS: 30 patients of low back pain radiating to lower extremities were randomized into two groups. We performed the psoas compartment block guided by C-arm fluoroscope. With the pateints in prone position, a 100 mm insulated needle was introduced at the surface of L5 transverse process. Stimulation of femoral nerve was used to optimize the needle placement at the center of lumbar plexus (Dancing Patella). 1% mepivacaine hydrochloride (0.2 ml/kg) solution in group 1 (n=11) and 0.5% mepivacaine hydrochloride (0.2 ml/kg) solution in group 2 (n=19) were then injected. We measured the minimal current, distance of puncture site from midline, distance from skin to transverse process, distance from skin to the point of maximal twitch, and distance from transverse process to the point of maximal twich. Motor and sensory functions were measured at 5, 15, 30, 45, 60, 90 and 120 min after procedure. RESULTS: Anatomical parameters were as follows; distance of puncture site from midline was 42.6 5.6 mm, distance from skin to transverse process was 52.9 +/- 7.0 mm, distance from skin to the point of maximal twitch was 68.8+/-5.6 mm, and distance from transverse process to the point of maximal twich is 15.9+/-3.9 mm. Difference in attenuated motor function(hip adduction, knee extension) was observed between two groups (P<0.05). Hip adduction and knee extension were recovered 60 min after injection in group 1. In group 2, knee extension was attenuated above 2 hours. We observed significant hip flexion attenuation 90 and 120 min (group 1 and group 2, etc) after injection Sensory blockade was recovered 120 min after injection in both groups. CONCLUSIONS: It is suggested that above mentioned anatomical parameters would be useful for the safe blockade. We found that recovery of attenuated hip flexion is crucial for the discharge criteria of ambulating outpatient with the low back pain.