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Ultrasound for central neuraxial blocks

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Abstract

Recent advances in ultrasound (US) imaging have significantly improved our understanding of spinal sonoanatomy. Today, US imaging has been used to assist or guide central neuraxial blocks, and it appears to be a promising alternative to traditional landmark-based technique. US is noninvasive, safe, simple to use, can be quickly performed, does not involve exposure to radiation, provides real-time images, and is free from adverse effects. Currently, the majority of the outcome data are from its application in the lumbar region. A scout (prepuncture) scan allows the operator to preview the spinal anatomy, identify the midline, accurately predict the depth to the epidural space, and determine the optimal site and trajectory for needle insertion. When used for central neuraxial blocks, it also improves the success rate of epidural access on the first attempt, reduces the number of puncture attempts or the need to puncture multiple levels, and improves patient comfort during the procedure. Preliminary data suggest that US may also offer technical advantages in patients with abnormal spinal anatomy. It is also an excellent teaching tool and improves the learning curve of epidural blocks in parturients. However, the use of US for central neuraxial blocks is still in its infancy, and there is a need for more research in this state of the art regional anesthesia before it can become a standard of care.

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... spinous processes were the interspinous spaces, and the hyperechoic reflections anteriorly were from the artificial ligamentum flavum and the anterior dura-posterior longitudinal ligament-vertebral body complex (anterior complex; Figure 2C). 1,7 The lamina also appeared hyperechoic and was the first osseous structure visualized on the paramedian sagittal scan ( Figure 3A). Because bone impedes the passage of ultrasound, there was an acoustic shadow anterior to each lamina. ...
... The sonographic appearance of the lamina produced a pattern, resembling the head and neck of a horse, which we refer to as the "horse head sign" ( Figure 3A). 1 A gap was also seen between adjoining lamina, which was the interlaminar space ( Figure 3A). The articular processes of the facet joints were the next osseous structures visualized lateral to the lamina. ...
Article
This report describes the preparation of a gelatin-agar spine phantom that was used for spinal sonography and to practice the hand-eye coordination skills required to perform sonographically guided central neuraxial blocks. The phantom was prepared by embedding a lumbosacral spine model into a mixture of gelatin and agar in a plastic box. Cellulose powder and chlorhexidine were also added to the mixture, after which it was allowed to solidify. Sonography of the osseous elements of the lumbosacral spine in the phantom was then performed, and their sonographic appearances were compared to those in volunteers. Simulated real-time sonographically guided paramedian spinal needle insertions were also performed in the phantom. The texture and echogenicity of the phantom were subjectively comparable to those of tissue in vivo. The osseous elements of the spine in the phantom were clearly delineated, and their sonographic appearances were comparable to those seen in vivo in the volunteers. During the simulated sonographically guided spinal injections, the needle could be clearly visualized, but the phantom provided little tactile feedback. In conclusion, the gelatin-agar spine phantom is a simple and inexpensive sonographic spine model that has a tissuelike texture and echogenicity. It can be used to study the osseous anatomy of the lumbar spine and practice the skills required to perform sonographically guided central neuraxial blocks.
... [18] A ultrassonografia é segura, livre de radiação, de simples execução e pode ser muito benéfica em pacientes que apresentam variações anatômicas da coluna vertebral. [19,20] No nosso estudo, utilizamos orientação ultrassonográfica durante a realização do bloqueio peridural caudal e não registramos complicações durante o processo de punção. Também minimizamos a possibilidade de falha do bloqueio caudal, aguardando o aumento do IP. ...
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Resumo Justificativa: O estresse cirúrgico causa resposta neuroendócrina, resultando em instabilidade hemodinâmica indesejável, modificações na resposta metabólica e disfunção no sistema imune. Objetivos: O objetivo deste estudo foi avaliar em pacientes pediátricos a eficácia do bloqueio peridural caudal no controle da dor intra e pós-operatória e na redução da resposta ao estresse nesses períodos. Métodos: Estudo clínico prospectivo randomizado que incluiu 60 pacientes submetidos à herniorrafia eletiva. Um grupo (n = 30) recebeu anestesia geral, e o outro (n = 30) anestesia geral combinada a bloqueio caudal. Foram medidos os parâmetros hemodinâmicos, o consumo de drogas e a intensidade da dor. Amostras de sangue para medir glicemia e cortisol plasmático foram obtidas antes da indução e após o despertar dos pacientes. Resultados: As crianças que receberam bloqueio peridural caudal apresentaram valores significantemente mais baixos para glicemia (p < 0,01), concentração de cortisol (p < 0,01) e escores de dor de 3 horas (p = 0,002) e 6 horas (p = 0,003) após a cirurgia, maior estabilidade hemodinâmica e menor consumo de drogas. Além disso, não foram observados efeitos colaterais ou complicações neste grupo. Conclusões: O bloqueio peridural caudal combinado à anestesia geral é uma técnica segura e que se associa o menor estresse, maior estabilidade hemodinâmica, redução nos escores de dor e baixo consumo de drogas.
... 18 Ultrasound is safe, radiation free, simple to perform and could be very helpful in patients with spinal anatomy variations. 19,20 In our study, we used ultrasound guidance while performing caudal blocks and recorded no complications during the puncture process. We have also minimized the possibility of a caudal fail by waiting for the increase in PI. ...
Article
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Background Surgery generates a neuroendocrine stress response, resulting in undesirable hemodynamic instability, alterations in metabolic response and malfunctioning of the immune system. Objectives The aim of this research was to determine the effectiveness of caudal blocks in intra- and postoperative pain management and in reducing the stress response in children during the same periods. Methods This prospective, randomized clinical trial included 60 patients scheduled for elective herniorrhaphy. One group (n = 30) received general anesthesia and the other (n = 30) received general anesthesia with a caudal block. Hemodynamic parameters, drug consumption and pain intensity were measured. Blood samples for serum glucose and cortisol level were taken before anesthesia induction and after awakening the patient. Results Children who received a caudal block had significantly lower serum glucose (p < 0.01), cortisol concentrations (p < 0.01) and pain scores 3 h (p = 0.002) and 6 h (p = 0.003) after the operation, greater hemodynamic stability and lower drug consumption. Also, there were no side effects or complications identified in that group. Conclusions The combination of caudal block with general anesthesia is a safe method that leads to less stress, greater hemodynamic stability, lower pain scores and lower consumption of medication.
... Combining various ultrasound scans allows to study the patient's vertebral column, exploring the anatomical structures to be crossed and recording relevant parameters for the anesthesiologist [2][3][4] such as intervertebral levels, depth of the epidural and subarachnoid space and to trace the optimal spinal needle entry point. The utility of ultrasound technique is more evident in expected difficult cases, when only superficial anatomical landmarks are poor, such as obesity or excessive thinness, and previous spinal surgery, or in case of deformity of the vertebral column [5]. ...
... Tabela 1Comprimentos (média ± DP) do ligamento longitudinal posterior (em mm), visibilizados por ultrassonografia por via paramediana à direita, no nível intervertebral L3-L4, em quatro posições sentadas em pacientes grávidas e um resumo das diferenças estatísticas entre cada uma das quatro posições de estudo sacral, os interespaços lombares e o espaço peridural ao nível de L3-4 foram prontamente identificáveis por ultrassonografia em todas as pacientes.8 A clareza da imagem do PLL foi adequada em todas as voluntárias, exceto em uma, na qual o PLL não pôde ser visibilizado. ...
Article
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Study objective: The purpose of this study was to assess whether application of dorsal table tilt and body rotation to a parturient seated for neuraxial anesthesia increased the size of the paramedian target area for neuraxial needle insertion. Setting: Labor and Delivery Room. Patients: Thirty term pregnant women, ASA I-II, scheduled for an elective C-section delivery. Interventions: Lumbar ultrasonography was performed in four seated positions: (F) lumbar flexion; (FR) as in position F with right shoulder rotation; (FT) as in position F with dorsal table-tilt; (FTR) as in position F with dorsal table-tilt combined with right shoulder rotation. Measurements: For each position, the size of the 'target area', defined as the visible length of the posterior longitudinal ligament was measured at the L3-L4 interspace. Main results: The mean posterior longitudinal ligament was 18.4±4mm in position F, 18.9±5.5mm in FR, 19±5.3mm in FT, and 18±5.2mm in FTR. Mean posterior longitudinal ligament length was not significantly different in the four positions. Conclusions: These data show that the positions studied did not increase the target area as defined by the length of the posterior longitudinal ligament for the purpose of neuraxial needle insertion in obstetric patients. The maneuvers studied will have limited use in improving spinal needle access in pregnant women.
... Tabela 1Comprimentos (média ± DP) do ligamento longitudinal posterior (em mm), visibilizados por ultrassonografia por via paramediana à direita, no nível intervertebral L3-L4, em quatro posições sentadas em pacientes grávidas e um resumo das diferenças estatísticas entre cada uma das quatro posições de estudo sacral, os interespaços lombares e o espaço peridural ao nível de L3-4 foram prontamente identificáveis por ultrassonografia em todas as pacientes.8 A clareza da imagem do PLL foi adequada em todas as voluntárias, exceto em uma, na qual o PLL não pôde ser visibilizado. ...
Article
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Study objective The purpose of this study was to assess whether application of dorsal table tilt and body rotation to a parturient seated for neuraxial anesthesia increased the size of the paramedian target area for neuraxial needle insertion. Setting Labor and Delivery Room. Patients Thirty term pregnant women, ASA I–II, scheduled for an elective C-section delivery. Interventions Lumbar ultrasonography was performed in four seated positions: (F) lumbar flexion; (FR) as in position F with right shoulder rotation; (FT) as in position F with dorsal table-tilt; (FTR) as in position F with dorsal table-tilt combined with right shoulder rotation. Measurements For each position, the size of the ‘target area’, defined as the visible length of the posterior longitudinal ligament was measured at the L3-L4 interspace. Main results The mean posterior longitudinal ligament was 18.4 ± 4 mm in position F, 18.9 ± 5.5 mm in FR, 19 ± 5.3 mm in FT, and 18 ± 5.2 mm in FTR. Mean posterior longitudinal ligament length was not significantly different in the four positions. Conclusions These data show that the positions studied did not increase the target area as defined by the length of the posterior longitudinal ligament for the purpose of neuraxial needle insertion in obstetric patients. The maneuvers studied will have limited use in improving spinal needle access in pregnant women.
... Using aseptic technique, the patients in the UG had their spines scanned using a convex transducer in the paramedian oblique sagittal view (Fig. 1). 8,9 When the preferred lumbar interspace came into view, local anaesthetic was infiltrated, and a spinal needle introducer was inserted in-plane to the ultrasound probe. The angle of introducer was adjusted in real time until it was pointed in between two vertebral laminae (Fig. 2) identified by palpation, as described previously. ...
... Blockade of various small sensory or mixed nerves, such as the ilioinguinal, genitofemoral, saphenous, lateral femoral cutaneous, suprascapular, pudendal, intercostal, greater occipital and various other sites may be more easily accomplished with ultrasound guidance. In addition, ultrasound guidance may be feasible for many spinal procedures, including epidurals, 22 selective spinal nerve blocks, facet joint, medial branch blocks 23 and sympathetic blocks (stellate ganglion, 24 lumbar sympathetic, celiac plexus). Finally, ultrasound guidance may aid placement of peripheral neuromodulation electrodes. ...
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Ultrasound is becoming popular in anaesthetic practice because of numerous advantages. Its introduction in pain medicine is recent and its use is growing. It allows the identification of soft tissues, vessels and nerves, without the risk of radiation. The additional advantages in pain medicine are avoidance of repeated radiations and ease of use in outpatient clinics, thus saving time and decreasing work load on interventional theatres. Ultrasound has multiple applications in pain medicine. It finds use in providing acute pain relief in the form of peripheral nerve blocks. In chronic pain, possible applications include blocks of cervical and lumbar facet joints, stellate ganglion block, intercostal nerve blocks, blocks of painful stump neuromas, caudal epidural injections and injections of trigger or tender points. The nerves can be visualised directly, thus helping in destructive processes like cryoanalgesia, radiofrequency lesioning and chemical neurolysis. The disadvantages are loss of resolution for deep-seated structures and lack of controlled trials. The article presents a review of ultrasound usage in acute and chronic pain interventional procedures.
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Proximal lateral gastrocnemius tendon injury is an overlooked cause of posterior knee pain. As the proximal gastrocnemius tendon attaches on the distal femur; its pain is more deeply located and can also be aggravated by flexion of the affected knee. In the present report, sonopalpation showed that the painful tendon appeared to have lost its fibrillary pattern and become thickened and hypoechoic as well. Under the diagnosis of proximal gastrocnemius tendon sprain, the ultrasound guided dextrose injection was performed and the pain was totally relieved.
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In performing neuraxial procedures, knowledge of the location of the conus medullaris in patients of all ages is important. The aim of this study was to determine the location of conus medullaris in a sample of newborn/infant cadavers and sagittal MRIs of children, adolescents, and young adults. The subjects of both the samples were subdivided into four developmental stages. No statistical difference was seen between the three older age groups (P > 0.05). A significant difference was evident when the newborn/infant stage was compared with the other, older stages (P < 0.001 for all comparisons). In the newborn/infant group the spinal cord terminated most frequently at the level of L2/L3 (16%). In the childhood stage, the spinal cord terminated at the levels of T12/L1 and the lower third of L1 (21%). In the adolescent population, it was most often found at the level of the middle third of L1 and L1/L2 (19%). Finally, in the young adult group, the spinal cord terminated at the level of L1/L2 (25%). This study confirmed the different level of spinal cord termination between newborns/infants less than one-year-old and subjects older than one year. In this sample the conus medullaris was not found caudal to the L3 vertebral body, which is more cranial than the prescribed level of needle insertion recommended for lumbar neuraxial procedures. It is recommended that the exact level of spinal cord termination should be determined prior to attempting lumbar neuraxial procedures in newborns or infants. Clin. Anat., 2014. © 2014 Wiley Periodicals, Inc.
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Caudal epidural anesthesia is the most popular regional anesthesia technique used in children. With advanced age, only the relative difficulty in localizing the sacral hiatus limits its use. However, in adults this technique has been widely used to control chronic pain by adjuvant use of fluoroscopy. Thus, the ability to locate the hiatus and define anatomical variations is the main determinant of the success and safety of caudal epidural anesthesia. In this context, the use of the ultrasound in caudal epidural anesthesia has been increasing. The objective of this review was to determine the role of the ultrasound in caudal epidural anesthesia and to demonstrate that this technique, widely used in children, is also useful and can be used in adults. A review of the literature on sacral anatomy and the anesthetic technique necessary to perform caudal epidural anesthesia was undertaken. Recent studies in ultrasound-guided caudal epidural anesthesia both in children and adults were also included. Despite its limitations, the ultrasound can be a useful tool to position the needle in the caudal space. It allows prompt identification of the sacral anatomy and real-time visualization of the injection. Considering it is portable, non-invasive, and free of radiation exposure, it is an attractive technique in the operating room especially in difficult cases. However, since its use in neuroaxis anesthesia is very primitive, more studies are necessary to make it a routine technique in anesthetic practice.
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The role of ultrasound in central neuraxial blockade has been underappreciated, partly because of the relative efficacy of the landmark-guided technique and partly because of the perceived difficulty in imaging through the narrow acoustic windows produced by the bony framework of the spine. However, this also is the basis for the utility of ultrasound: an interlaminar window that permits passage of sound waves into the vertebral canal also will permit passage of a needle. In addition, ultrasound aids in identification of intervertebral levels, estimation of the depth to epidural and intrathecal spaces, and location of important landmarks, including the midline and interlaminar spaces. This can facilitate neuraxial blockade, particularly in patients with difficult surface anatomic landmarks. In this review article, the authors summarize the current literature, describe the key ultrasonographic views, and propose a systematic approach to ultrasound imaging for the performance of spinal and epidural anesthesia in the adult patient.
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Caudal epidural is the most popular regional analgesia and anesthesia technique in pediatrics. The use of ultrasound (US) guidance in this procedure, is not yet the standard, but could reduce the risks related with the traditional approach and offer some advantages. We described a case of a 4-years-old patient undergoing a resection of a rabdomyosarcome on the left thigh plus inguinal metastatic nodes and implantation of brachitherapy catheters, in whom a continous caudal epidural catheter was placed under US guidance. After general anesthesia induction, a scout scanning identified the anatomy and afterwards, using strict aseptic techniques a caudal catheter was indwelling under the US guidance on real time and using the Doppler mode confirm the position of it inside the caudal epidural space with a local anesthetic bolus. There was an optimal pain control after surgery. The use of US as a guidance tool for caudal epidural catheter placement is an excellent alternative to the classic anatomical landmarks and give some advantages compare with those blind techniques.
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Background and objectives: Ultrasound assessment of the lumbar spine improves the success of spinal and epidural anesthesia, especially for patients with underlying difficult anatomy. To assist with the teaching and learning of ultrasound-guided neuraxial anesthesia, we have created an online interactive educational model (http://www.usra.ca/vspine.php and http://pie.med.utoronto.ca/vspine). The aim of the current study was to determine whether the virtual spine model improved the knowledge of neuraxial anatomy and sonoanatomy. Methods: After obtaining ethics board approval and written participant consent, 14 anesthesia trainees with no prior experience with spine ultrasound imaging were included in this study. Construct validity was assessed using a pretest/posttest design to measure the knowledge acquired from self-study of the virtual spine simulation modules. Two tests (A and B) with 20 multiple-choice questions were used either for the pretest or posttest, at random in order to account for possible differences in difficulty between the 2 tests. These tests were administered immediately before and after a 1-hour training session using the spine ultrasound model. Results: Fourteen anesthesia trainees completed the study. Seven used test A as the pretest (group A), and 7 used test B as the pretest (group B). Both groups showed a statistically significant improvement (P < 0.05) in test scores after a 1-hour session with the spine ultrasound model. The mean scores were 55% (SD, 11.2%) on the pretest and 77% (SD, 8.7%) on the posttest. Conclusions: The study demonstrated that after 1 hour of self-study by the trainees on the spine ultrasound model test scores improved by 40%.
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JUSTIFICATIVA E OBJETIVOS: O bloqueio peridural caudal é a mais popular entre todas as técnicas de anestesia regional em crianças. Com o avanço da idade, apenas a relativa dificuldade em localizar o hiato sacral limita seu uso. Entretanto, em adultos a técnica vem sendo largamente utilizada para controle de dor crônica com o auxílio da fluoroscopia. Assim, a habilidade em localizar o hiato e definir as variações anatômicas é o principal fator determinante do sucesso e segurança na execução do bloqueio peridural pela via caudal. Nesse contexto, o ultrassom vem ganhando espaço como guia para a realização do bloqueio caudal. O objetivo desta revisão foi elucidar o papel do ultrassom na anestesia caudal, além de demonstrar que o bloqueio caudal, muito utilizado em crianças, também é útil e pode ser usado em adultos. CONTEÚDO: Uma revisão literária sobre a anatomia da região sacral e da técnica anestésica necessária para a realização adequada do bloqueio caudal foi promovida. Além disso, artigos recentes sobre estudos realizados com bloqueios peridurais caudais guiados por ultrassom tanto em crianças quanto em adultos também foram incluídos. CONCLUSÕES: O ultrassom, apesar de suas limitações, pode ser útil como ferramenta adjuvante no posicionamento da agulha no espaço caudal. Permite a fácil identificação da anatomia sacral, além de visualização da injeção, em tempo real. Sua natureza portátil, não invasiva e livre de exposição à radiação faz dele uma tecnologia atrativa na sala operatória, principalmente na emergência de casos difíceis. Entretanto, como seu uso em bloqueios centrais do neuroeixo ainda é muito primitivo, é necessário que mais pesquisas sejam feitas para se consagre como técnica de rotina na prática anestésica.
Article
The lateral costotransverse ligament, a short band that stabilizes the costovertebral joint, is found in close proximity to the dorsal root ganglion. This ligament is an important surgical landmark during tumor resections or nerve blocks in the paravertebral space. The purpose of this study was to quantitatively and qualitatively describe the morphology of the lateral costotransverse ligament and its relation to the dorsal root ganglion at all levels of the thoracic spine. The thoracic spines of eight embalmed cadavers were dissected bilaterally. The length, width, and thickness of the ligament were measured. The distance from the inferolateral aspect of the ligament to the lateral aspect of the dorsal root ganglion was also measured. Three bilateral groups of lateral costotransverse ligaments, top (on ribs 1-2), middle (on ribs 3-10), and bottom (on ribs 11-12), were compared based on anatomic distinctions between the costotransverse joints, which can influence ligament morphology. Among the three groups, the differences between the length, width, and thickness were not statistically significant. However, the distance from the lateral costotransverse ligament to the dorsal root ganglion differed significantly (P = 0.000), with the middle group having the longest distance, and the bottom group having the shortest distance. This finding can help clinicians and surgeons avoid iatrogenic injuries of neural structures during thoracic spine surgery, or when performing nerve blocks in the paravertebral space.
Article
Background: Neuraxial anesthesia can be challenging in obstetric patients due to the gravid uterus interfering with patient positioning. Ultrasound is commonly used in obstetric anesthesia to facilitate neuraxial needle placement. Some positioning maneuvers facilitate the ultrasound visualization of structures and the placement of neuraxial needles, but the Epidural Positioning Device (EPD) has yet to be evaluated. Objectives: Our goal was to evaluate whether the use of the EPD increased the acoustic target window in the lumbar area of pregnant patients. We hypothesized that the application of the EPD would increase the measured lengths of the paravertebral longitudinal ligament (PLL), the interlaminar distance (ILD) and the ligamentum flavum (LF). Methods: Lumbar ultrasonography was performed on 29 pregnant women having an elective cesarean delivery. Two anesthesiologists independently scanned the L3-4 right paramedian space, using a curvilinear ultrasound transducer, in two positions for each patient: traditional sitting with lumbar flexion and sitting with use of the EPD for lumbar flexion. The PLL, ILD and LF lengths were measured using the ultrasound caliper software and recorded, with the anesthesiologists blinded to the results. Patients were asked to rate their comfort in both positions. Results: There were no significant differences between the measured lengths of the PLL, ILD and LF in the two positions. Patient comfort was significantly higher with use of the EPD (OR 10, 95% CI 2.4 to 88). Conclusion: Although the application of an EPD did not improve the paramedian acoustic target area in term parturients, greater patient comfort might facilitate needle placement.
Chapter
Neuraxial anesthesia and analgesia techniques (spinal, epidural, and combined spinal epidural) are used for intraoperative anesthesia, postoperative pain control, and the management of chronic pain and in the peripartum period. Traditionally, these procedures are performed using anatomical landmarks. This involves the location of nerves in relation to other anatomic structures that can be seen (i.e., bony structures) or palpated (i.e., bony structures and arterial pulses). Ultrasound guidance can further aid in the ease and success of these procedures through direct visualization of neural structures as well as the spread of local anesthetic. In this chapter, we discuss a variety of ultrasound-guided neuraxial procedures including epidural block, paravertebral block, sacroiliac joint injection, lumbar facet joint injection, and epidural blood patch.
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The implementation of US imaging can revolutionize regional anesthesia. There are diverse applications. Quality improvements The implementation of US imaging can revolutionize regional anesthesia. There are diverse applications. Quality improvements in epidural and peripheral29 regional anesthesia/analgesia can be achieved. Teaching is enhanced and learning curves may be shortened. US may facilitate in epidural and peripheral29 regional anesthesia/analgesia can be achieved. Teaching is enhanced and learning curves may be shortened. US may facilitate research that may eventually help make regional anesthesia more efficacious and safer than it already is. Side effects and research that may eventually help make regional anesthesia more efficacious and safer than it already is. Side effects and complications may be reduced and when a complication occurs it may be more readily identified and controlled treatment may complications may be reduced and when a complication occurs it may be more readily identified and controlled treatment may be possible with US guidance (e.g., epidural blood patch). Continuing evolution of US technology may further expand the potential be possible with US guidance (e.g., epidural blood patch). Continuing evolution of US technology may further expand the potential for US in regional anesthesia/analgesia. for US in regional anesthesia/analgesia.
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Current methods of locating the epidural space rely on surface anatomical landmarks and loss-of-resistance (LOR). We are not aware of any data describing real-time ultrasound (US)-guided epidural access in adults. We evaluated the feasibility of performing real-time US-guided paramedian epidural access with the epidural needle inserted in the plane of the US beam in 15 adults who were undergoing groin or lower limb surgery under an epidural or combined spinal-epidural anaesthesia. The epidural space was successfully identified in 14 of 15 (93.3%) patients in 1 (1-3) attempt using the technique described. There was a failure to locate the epidural space in one elderly man. In 8 of 15 (53.3%) patients, studied neuraxial changes, that is, anterior displacement of the posterior dura and widening of the posterior epidural space, were seen immediately after entry of the Tuohy needle and expulsion of the pressurized saline from the LOR syringe into the epidural space at the level of needle insertion. Compression of the thecal sac was also seen in two of these patients. There were no inadvertent dural punctures or complications directly related to the technique described. Anaesthesia adequate for surgery developed in all patients after the initial spinal or epidural injection and recovery from the epidural or spinal anaesthesia was also uneventful. We have demonstrated the successful use of real-time US guidance in combination with LOR to saline for paramedian epidural access with the epidural needle inserted in the plane of the US beam.
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To describe the anesthetic implications, and management of a medically complex parturient, who presented for Cesarean delivery (CD). The patient had poliomyelitis complicated with severe kyphoscoliosis, which had been treated with extensive spinal surgery. We used ultrasound guidance to facilitate successful spinal analgesia and anesthesia. A 27-yr-old woman, with a history of poliomyelitis and moderate restrictive lung disease secondary to kyphoscoliosis, presented at 38 weeks gestation for elective CD because of cephalopelvic disproportion. The woman had Harrington rods in situ from the level of the second thoracic vertebra, to the level of the fourth lumbar vertebra. Ultrasound guidance enabled one intervertebral space to be visualized (L5-S1), 3 cm from the expected spinal midline, and spinal anesthesia was performed at this interspace without any complications. A healthy infant was delivered, and the mother recovered uneventfully. Spinal anesthesia can be effectively performed in patients with poliomyelitis and severe kyphoscoliosis, that has been treated with extensive Harrington instrumentation. To facilitate regional techniques in such patients, bedside ultrasound may be greatly beneficial in identifying the correct spinal interspace.
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Unlabelled: The infraclavicular brachial plexus block first described by Raj et al. was supposed to anesthetize all the main peripheral nerves of the brachial plexus without the risk of pneumothorax. However, in performing the block, we have had difficulties finding the nerves at the cord level. Therefore, we questioned whether the recommended needle direction (the "Raj line") guides the needle close enough to the cords. We therefore designed an anatomic study to answer this question and to assess the risks of entering the pleura and axillary vein. Ten volunteers were examined noninvasively in an open model magnetic resonance scanner. The Raj line deviated greatly from a defined location on the cords by a mean of 26 (range 14-39) mm, always caudad, and posterior to the target in nine cases. Further, the needle trajectory's shortest distance to the pleura was only 10 (0-27) mm, and in one case, it hit the pleura. Finally, the Raj line's distance to the axillary vein was also short, 11 (0-18) mm. We conclude that a modification of the method is necessary to guide the needle closer to the cords and further away from the pleura and the axillary vein. A more lateral needle insertion seems beneficial. Implications: Using a magnetic resonance scanner, the anatomical basis of Raj's infraclavicular method for brachial plexus blockade was examined in volunteers. The results show that the method should be modified to make it more precise and to provide less risk of complications.
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Lumbar puncture (LP) may be unsuccessful clinically, prompting image-guided LP by radiologists. Objective. To investigate the utility of ultrasound (US) in diagnosing the cause of failed LP and in guiding LP. Neonates and infants referred for image-guided LP underwent spine US of the thecal sac. When indicated, image-guided LP was performed. Forty-seven evaluations and interventions were performed in 32 patients. All patients were initially evaluated after failed blind LP attempts. Twenty-three of the initial US studies showed intrathecal and/ or epidural echogenic hematoma, which obliterated the CSF space; 5 showed minimal fluid, and 4 had normal examinations. LP was deferred or cancelled in 14 cases based upon initial US findings. Image-guided LP was performed 32 times in 19 patients. US guidance was used in 26, fluoroscopy in 3, and fluoroscopy with US assistance in 3. Using US, LP was performed in 9 patients with no visible CSF: 2 samples were sufficient for culture only. Six patients had minimal CSF US: 4 provided usable CSF samples. Clear CSF space was seen in 11: all had successful LP. US can disclose the cause of failed LP, can help determine whether or not to intervene further, and can provide guidance for LP.
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Epidural anesthesia may be difficult in pregnancy. We intended to evaluate the teaching possibilities of ultrasonography as a diagnostic approach to the epidural region. Two groups of residents performed their first 60 obstetric epidurals under supervision. One proceeded in the conventional way using the loss of resistance technique (control group = CG). The other group proceeded in the same way but was supported by prepuncture ultrasound imaging, giving them information about the optimal puncture point, depth and angle (ultrasound group = UG). Success was defined as adequate epidural anesthesia requiring a maximum of three attempts, reaching a visual analogue scale score of less than 1, while neither changing the anesthesia technique, nor starting at another vertebral level. In addition, intervention by the supervisor was defined as failure. In the CG we observed a success rate of 60% +/- 16% after the first ten attempts followed by a nearly continuous rise of the learning curve. Within the next 50 epidurals the rate of success increased to 84%. In the UG the rate of success started at 86% +/- 15%. Within 50 epidural insertions it rose up to a level of 94%. The difference between the two groups remained significant (P < 0.001). Using ultrasound imaging for teaching epidural anesthesia in obstetrics we found a higher rate of success during the first 60 attempts compared to conventional teaching. We believe this shows the possible value of ultrasound imaging for teaching and learning obstetric regional anesthesia.
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Although ultrasound has been used in administering epidural anesthesia, it is unknown if emergency physicians (EPs) can obtain ultrasound images useful for lumbar puncture. The objective of the study was to determine EPs' ability to apply a standardized ultrasound technique for visualizing landmarks surrounding the dural space. Two EPs sought to identify relevant anatomy in emergency patients. Visualization time for 5 anatomical structures (spinous processes or laminae, ligamentum flavum, dura mater, epidural space, subarachnoid space), body mass index, and perception of landmark palpation difficulty were recorded. Seventy-six subjects were enrolled. Soft tissue and bony anatomical structures were identified in all subjects. Mean body mass index was 31.4 +/- 9.8 (95% confidence interval, 29.1-33.6). High-quality images were obtained in less than 1 minute in 153 (87.9%) scans and in less than 5 minutes in 174 (100%) scans. Mean acquisition time was 57.19 seconds; SD, 68.14 seconds; range, 10 to 300 seconds. In this cohort, EPs were able to rapidly obtain high-quality ultrasound images relevant to lumbar puncture.
Article
Obesity and edema frequently obscure anatomic landmarks and result in technical difficulties during epidural anesthesia administration. However, the method of indirect sonographic guidance permits identification of the midline by sagittal scan of the laminae of lumbar vertebrae 2, 3, and 4. Thirty-six obese women scheduled for elective repeat cesarean delivery were prospectively studied. Use of a 5-MHz transducer positioned with the transducer center site over the second or third interspace allowed measurement of skin-to-lamina distance by the electronic calipers of a Toshiba SAL-32B or RT 3000 GE machine, prediction of needle depth for epidural puncture (EP), and skin marking of the site. After the transducer was removed, a 9.5- or 11.4-cm Tuohy needle was percutaneously advanced perpendicularly from the site until EP was achieved. Needle depth was measured by marker and measure, and epidural anesthesia was successfully administered to all patients. Simple linear regression analysis was performed with strong positive results. Indirect and continuous sonographic guidance studies designed to determine whether sonography reduces complications are planned.
Article
Seventy-five patients requesting extradural analgesia for the relief of pain in labour underwent an ultrasound scan to measure the depth to the extradural space. There was a high degree of correlation between these measurements and the subsequent depth of insertion of the Tuohy needle. The advantages of the technique in clinical practice and as an aid to teaching, are discussed
Article
Lumbar epidural anesthesia was performed in 26 patients by an anesthesiology resident at either the L2-L3 or L3-L4 interspace using the loss-of-resistance technique. Measurements obtained ultrasonically the night before were not available to this resident. In the 22 successful epidural anesthetics, a good correlation between predicted distance (ultrasound) and measured needle distance occurred (r=0.99, p<0.0001). Average distance to the epidural space was 4.6 cm by both a priori ultrasound and a posteriori needle measurements. Among the 26 lumbar epidural anesthetics, four blocks were unsuccessful. Two unsuccessful blocks were characterized by a centimeter difference between the ultrasound measured distance and the needle measured distance. The other two unsuccessful blocks were due to accidental dislodgement of the catheter from the epidural space with removal of the needle.
Article
The study was designed to examine a new method of confirming proper caudal needle placement using nerve stimulation. Thirty-two pediatric patients were studied. A 22-gauge insulated needle was inserted into the caudal canal via the sacral notch until a "pop" was felt. The needle placement was classified as correct or incorrect depending upon the presence or absence of anal sphincter contraction (S2-S4) to electrical simulation (1 to 10 mA). Three patients were excluded, two because they inadvertently received neuromuscular blockers and one because the patient's anatomy precluded any attempt at a caudal block. The sensitivity and specificity of the test were both 100% in predicting clinical outcomes of the caudal block. Six patients had a negative stimulation test after the first attempt to place the needle. Four of these went on to receive a second attempt of needle insertion after a subcutaneous bulge or resistance to local anesthetic injection were observed. Following needle reinsertion, positive stimulation tests were elicited. These patients received the local anesthetic injection with ease and had good analgesia postoperatively. No attempt was made to reinsert the needle in the remaining two patients with a negative stimulation test, as they did not show subcutaneous bulge or resistance upon injection. These patients had poor analgesia postoperatively. The positive predictive value of the test was greater than the presence of a "pop" alone (P < 0.05) but not significantly different (P = 0.492) over the presence of "pop" and easy injection. This test may be used as a teaching and adjuvant tool in performing caudal block.
Article
Coeliac plexus blocks have been used successfully in the treatment of abdominal pain in advanced cancer and in benign chronic abdominal pain. However, concern remains about occasional potentially serious complications. One possible way to reduce the risks of this procedure may be to improve imaging during the procedure. We report a series of 38 coeliac plexus blocks carried out under computer tomographic (CT) guidance, mostly using the anterior approach. The technique is described. Effectiveness and side-effect rates were similar to other reported series. There were no major complications. Analysis of contrast spread would indicate that anterior preaortic or bilateral contrast spread is necessary to obtain pain relief. Our experience would indicate that routine CT guidance can be a simple aid to coeliac plexus block, and can be achieved easily in a district general hospital. Improved imaging allows accurate needle placement, while avoiding vital structures such as the aorta and pleura. Accurate placement may also allow the use of reduced volumes of neurolytic drugs.
Article
We describe a patient with severe scoliosis, which had been corrected partially with Harrington rods, who requested epidural analgesia for labour. With no palpable landmarks, the use of ultrasound enabled identification of the vertebral midline and allowed provision of regional anaesthesia.
Article
Anaesthetists' ability to identify correctly a marked lumbar interspace was assessed in 100 patients undergoing spinal magnetic resonance imaging scans. Using ink, one anaesthetist marked an interspace on the lower spine and attempted to identify its level with the patient in the sitting position. A second anaesthetist attempted to identify the level with the patient in the flexed lateral position. A marker capsule was taped over the ink mark and a routine scan performed. The actual level of markers ranged from one space below to four spaces above the level at which the anaesthetist believed it to be. The marker was one space higher than assumed in 51% of cases and was identified correctly in only 29%. Accuracy was unaffected by patient position (sitting or lateral), although it was impaired by obesity (p = 0.001) and positioning of the markers high on the lower back (p < 0.001). The spinal cord terminated below L(1) in 19% of patients. This, together with the risk of accidentally selecting a higher interspace than intended for intrathecal injection, implies that spinal cord trauma is more likely when higher interspaces are selected.
Article
In patients with suspected subarachnoid hemorrhage (SAH) and negative CT findings, the iatrogenic introduction of RBCs into the CSF during lumbar puncture may lead to a misdiagnosis. We tested the hypothesis that the risk of traumatic lumbar puncture is lower with the fluoroscopy-guided technique than with the standard bedside technique. Data were collected retrospectively from two populations: adult inpatients undergoing standard bedside lumbar puncture for any reason and adult patients undergoing fluoroscopy-guided lumbar puncture for myelography. Patients with SAH and CSF samples with significant abnormalities other than erythrocytosis (ie, CSF leukocytosis, xanthochromia, or elevated protein) were excluded. In all, 1489 bedside procedures and 723 fluoroscopy-guided procedures met the criteria. We found a significant difference in the level of iatrogenic CSF erythrocytosis produced by the two procedures. Using a cutoff of 1000 cells/mm(3), the frequency of traumatic lumbar puncture was 10.1% for bedside lumbar puncture and 3.5% for fluoroscopy-guided lumbar puncture. With fluoroscopic guidance, the frequency of a traumatic tap varied significantly with the operator, ranging from 0% to 24%. The use of fluoroscopy-guided lumbar puncture in patients with suspected SAH and negative CT findings should reduce the frequency of false-positive diagnoses of acute SAH as well as the number of unnecessary angiograms for patients with suspected SAH but no underlying intracranial vascular malformation.
Article
Seven cases are described in which neurological damage followed spinal or combined spinal-epidural anaesthesia using an atraumatic spinal needle. All patients were women, six obstetric and one surgical. All experienced pain during insertion of the needle, which was usually believed to be introduced at the L2-3 interspace. In all cases, there was free flow of cerebrospinal fluid before spinal injection. There was one patchy block but, in the rest, anaesthesia was successful. Unilateral sensory loss at the levels of L4-S1 (and sometimes pain) persisted in all patients; there was foot drop in six and urinary symptoms in three. Magnetic resonance imaging showed a spinal cord of normal length with a syrinx in the conus (n = 6) on the same side as both the persisting clinical deficit and the symptoms that had occurred at insertion of the needle. The tip of the conus usually lies at L1-2, although it may extend further. Tuffier's line is an unreliable method of identifying the lumbar interspaces, and anaesthetists commonly select a space that is one or more segments higher than they assume. Because of these sources of error, anaesthetists need to relearn the rule that a spinal needle should not be inserted above L3.
Article
The efficacy of epidural anaesthesia depends on the accurate identification of the epidural space (ES). Abnormal anatomical conditions may make the procedure difficult or impossible. The aim of this study was to investigate whether pre-puncture ultrasound examination of the spinal anatomy might be beneficial in expected cases of difficult epidural anaesthesia. We used digital ultrasound equipment with a 5-MHz transducer to assess the anatomy of the ES and the posterior parts of the spinal column. We examined 72 parturients with abnormal anatomical conditions who were scheduled for epidural anaesthesia. The women were randomised into two equal groups. In all patients, the standard loss of resistance technique was used. In the ultrasound group, an ultrasound examination of the appropriate spinal region was conducted prior to epidural puncture. ES depth seen on the ultrasound images was compared to the ES depth measured by the needle. We compared the number of puncture attempts with the standard method (control group) to the number of attempts under ultrasound guidance. Ultrasonography significantly improved operating conditions for epidural anaesthesia. The maximum VAS scores and patient acceptance were significantly better. With ultrasound measurement of the ES depth, the quality of epidural anaesthesia was enhanced.
Article
The accuracy of ultrasound imaging to identify lumbar intervertebral level was assessed in 50 patients undergoing X-ray of the lumbar spine. Using an ultraviolet marker, an anaesthetist attempted to mark the L2/3, L3/4 and L4/5 intervertebral spaces. A radiologist unaware of these marks attempted to mark the same spaces with the aid of ultrasound imaging. X-ray-visible pellets were taped to the back at the various marks prior to lateral lumbar X-ray. Ultrasound imaging identified the correct level in up to 71% of cases, but palpation was successful in only 30% (p < 0.001). Up to 27% of marks using the palpation method were more than one spinal level above or below the assumed level using palpation, but none were more than one level high or low using ultrasound guidance.
Article
In thoracic epidural anesthesia, the "loss of resistance" technique is the standard technique for the identification of the epidural space (EDS), the feedback to the operator is often solely tactile. Our aim was to establish ultrasonography for the prepuncture demonstration of the anatomic structures surrounding the thoracic EDS and to evaluate its precision and imaging quality. We examined 20 volunteers. In each participant, the extradural space and the neighboring anatomic landmarks in the intervertebral space Th 5-6 were identified using 2 imaging techniques: magnetic resonance imaging (MRI) and ultrasonography. We compared corresponding images regarding distance measurements and the visibility of anatomic landmarks. The capacity of ultrasound imaging (US) to depict the thoracic EDS was limited. Due to the better overview, MR images were easier to interpret. However, US proved to be of better value than MRI in the depiction of the dura mater. All important landmarks for the puncture of the thoracic EDS could be identified with both techniques. The overall correlation was satisfactory. US depicted the different structures of the thoracic EDS with an acceptable precision (confidence interval, 4.6 to 8.7 mm). US showed good correlation with MRI, which is a standard imaging technique for the depiction of the spine. We anticipate that prepuncture ultrasonography may facilitate thoracic epidural anesthesia by needle placement.
Article
To assess the clinical use of ultrasonographic localization of the epidural space, and to evaluate the clinical efficacy of ultrasound diagnostics in obstetric anesthesia. Randomized prospective study. University Clinic of Obstetrics and Gynecology. 300 parturients, 85 of whom had conventional delivery and 65 who underwent cesarean section. Patients underwent ultrasonography for the identification of the intervertebral structures. Puncture depth and angle were measured to improve the placement of the Tuohy needle. In the ultrasound group, additional puncture data, optimized puncture point, expected puncture depth, and angle were used to optimize the puncture technique. To control for side effects, we compiled data on the number of puncture attempts and the number of necessary puncture levels, visual analog scale (VAS) scores, the rate of side effects, and the patient acceptance of the technique. The two groups were similar regarding demographic data. Using ultrasound for structure detection, the rate of puncture attempts were significantly (p < 0.013) reduced from 2.18 +/- 1.07 to 1.35 +/- 0.61. The mean rate of necessary puncture levels was 1.30 +/- 0.55 and with ultrasound detection 1.136 +/- 0.36 (p < 0.029). Complete analgesia was achieved in 147 patients with ultrasound detection versus 138 patients in the Control group (p < 0,03). The maximum VAS pain score in the control group was 1.3 +/- 2.1 versus 0.8 +/- 1.5 in the Ultrasound group (p < 0.006). The rate of side effects were reduced significantly: 99 patients in the Control group had no side effects compared with 120 patients from the Ultrasound group who were free of side effects. Patient acceptance of the technique in the Ultrasound group was significantly higher than in the Control group. The clinical use of ultrasound for epidural catheter placement may improve regional anesthesia. The use of ultrasound resulted in superior quality in all measured endpoints.
Article
The authors report five patients with damage to the distal spinal cord following spinal anesthesia. The patients developed leg weakness and sensory disturbance. MRI of the lumbosacral spine showed an abnormal area of high signal within the conus medullaris in all patients. Symptoms and signs persisted at 1- to 2.5-year follow-ups. Incorrect needle placement and type of needle used are possible factors leading to spinal cord injury.
Article
The quality of combined spinal-epidural anaesthesia mainly depends on accurate identification of the epidural space. The real-time ultrasound control of the procedure for puncture was therefore evaluated. Thirty parturients scheduled for Caesarean section were randomized to three equal groups. Ten control patients received conventional combined spinal-epidural anaesthesia. Ten of the remaining patients received ultrasonic scans by an offline scan technique, and 10 received online imaging of the lumbar region during epidural puncture. The epidural space was identified and needle advancement was surveyed through the interspinal and flaval ligaments. The number of attempts to advance the needle to achieve a successful puncture was measured and compared, as well as the number of vertebral interspaces punctured before successful entry into the epidural space. There was no difference between patient characteristics in the three groups. The visualization of the epidural structures and of the needle manipulations was very effective. In the ultrasound group, the reduction in the number of attempts at puncture was significant (P < 0.036). The number of interspaces necessary for puncture was reduced (P < 0.036) in the ultrasound online group compared with controls. The number of spinal needle manipulations was significantly reduced (P < 0.036). Real-time ultrasonic scanning of the lumbar spine is an easy procedure. It provides an accurate reading of the location of the needle tip and facilitates the performance of combined spinal-epidural anaesthesia.
Article
Lumbar facet nerve (medial branch) block for pain relief in facet syndrome is currently performed under fluoroscopic or computed tomography scan guidance. In this three-part study, the authors developed a new ultrasound-guided methodology, described the necessary landmarks and views, assessed ultrasound-derived distances, and tested the clinical feasibility. (1) A paravertebral cross-axis view and long-axis view were defined under high-resolution ultrasound (15 MHz). Three needles were guided to the target point at L3-L5 in a fresh, nonembalmed cadaver under ultrasound (2-6 MHz) and were subsequently traced by means of dissection. (2) The lumbar regions of 20 volunteers (9 women, 11 men; median age, 36 yr [23-67 yr]; median body mass index, 23 kg/m2 [19-36 kg/m2]) were studied with ultrasound (3.5 MHz) to assess visibility of landmarks and relevant distances at L3-L5 in a total of 240 views. (3) Twenty-eight ultrasound-guided blocks were performed in five patients (two women, three men; median age, 51 yr [31-68 yr]) and controlled under fluoroscopy. In the cadaver, needle positions were correct as revealed by dissection at all three levels. In the volunteers, ultrasound landmarks were delineated as good in 19 and of sufficient quality in one (body mass index, 36 kg/m2). Skin-target distances increased from L3 to L5, reaching statistical significance (*, **P < 0.05) between these levels on both sides: L3r, 45+/-6 mm*; L4r, 48+/-7 mm; L5r, 50+/-6 mm*; L3l, 44+/-5 mm**; L4l, 47+/-6 mm; L5l, 50+/-6 mm**. In patients, 25 of 28 ultrasound-guided needles were placed accurately, with the remaining three closer than 5 mm to the radiologically defined target point. Ultrasound guidance seems to be a promising new technique with clinical relevance and the potential to increase practicability while avoiding radiation in lumbar facet nerve block.
Article
This study was conducted to investigate the feasibility of using ultrasound as an image tool to locate the sacral hiatus accurately for caudal epidural injections. Between August 2002 and July 2003, 70 patients (39 male and 31 female patients) with low back pain and sciatica were studied. Soft tissue ultrasonography was performed to locate the sacral hiatus. A 21-gauge caudal epidural needle was inserted and guided by ultrasound to the sacral hiatus and into the caudal epidural space. Proper needle placement was confirmed by fluoroscopy. In all the recruited patients, the sacral hiatus was located accurately by ultrasound, and the caudal epidural needle was guided successfully to the sacral hiatus and into the caudal epidural space. There was 100% accuracy in caudal epidural needle placement into the caudal epidural space under ultrasound guidance as confirmed by contrast dye fluoroscopy. Ultrasound is radiation free, is easy to use, and can provide real-time images in guiding the caudal epidural needle into the caudal epidural space. Ultrasound may therefore be used as an adjuvant tool in caudal needle placement.
Article
The technology and clinical understanding of anatomical sonography has evolved greatly over the past decade. In the Department of Anaesthesia and Intensive Care Medicine at the Medical University of Vienna, ultrasonography has become a routine technique for regional anaesthetic nerve block. Recent studies have shown that direct visualization of the distribution of local anaesthetics with high-frequency probes can improve the quality and avoid the complications of upper/lower extremity nerve blocks and neuroaxial techniques. Ultrasound guidance enables the anaesthetist to secure an accurate needle position and to monitor the distribution of the local anaesthetic in real time. The advantages over conventional guidance techniques, such as nerve stimulation and loss-of-resistance procedures, are significant. This review introduces the reader to the theory and practice of ultrasound-guided anaesthetic techniques in adults and children. Considering their enormous potential, these techniques should have a role in the future training of anaesthetists.
Article
Lumbar puncture is a common procedure performed in the emergency department for evaluation of several life-threatening conditions, including meningitis and subarachnoid hemorrhage. We describe the use of bedside ultrasound to assist in performance of the lumbar puncture in situations where the standard "blind" technique of needle insertion using palpable spinal landmarks is likely to be difficult or to fail. Use of ultrasound to guide lumbar puncture needle placement was originally reported 30 years ago in the Russian literature. More recently, ultrasound has been used for guiding needle placement for epidural and spinal anesthesia by anesthesiologists and for diagnostic lumbar puncture on infants by radiologists.
Article
Unlabelled: Epidural catheters (EC) are often used in pediatric patients for intraoperative and postoperative pain relief. The small anatomical structures and catheter insertion under general anesthesia make it more difficult to perform EC and to prevent damage. In this study we investigated the use of ultrasound (US) in detecting neuraxial structures during insertion and placement of EC in children. ASA I-II children scheduled for elective surgery under combined general and epidural anesthesia were studied. Patients received balanced anesthesia using sevoflurane, opioids and rocuronium. Before EC insertion US examination in a lateral position was done to visualize and identify neuraxial structures. Quality of visualization and site and depth of structures were recorded. Using a sterile kit to hold the US probe in position and enable the visualization of the neuraxial structures, an epidural cannula was inserted, using the loss of resistance technique, as the EC passed under US control to the desired level. Of 25 children, 23 were evaluated. Epidural space, ligamentum flavum, and dural structures were clearly identified and the depth to skin level estimated in all patients. Loss of resistance was visualized in all patients with a lumbar epidural approach. Correlation of US measured depth and depth of loss of resistance was 0.88. In eight of 23 patients EC could be visualized during insertion and in 11 others it could be visualized with additional US planes. US is an excellent tool to identify neuraxial structures in both infants and children. The size and the incomplete ossification of the vertebra allow exact visualization and localization of the depth of the epidural space, the loss of resistance, and all relevant neuraxial structures. Implications: Epidural catheters in children are mostly inserted under sedation or general anesthesia. This study showed that the use of ultrasound could help visualize all relevant neuraxial structures and their site and depth from the skin.
Article
Epidural cannulation is a difficult technique in the patient undergoing scoliosis repair, due to axial rotation of the vertebral bodies, as well as angulation of the spinal processes. This case series was performed to investigate whether ultrasonography could facilitate epidural insertion in patients with scoliosis, by assessing the degree of vertebral body rotation. Eleven patients scheduled for corrective scoliosis surgery were studied. The spine was examined ultrasonically using a portable ultrasound system with a 38-mm linear probe in two-dimensional B mode. The angulation of the probe head (measured using an inclinometer held in alignment with its long axis) at which the echo signals from the laminae became level on the screen was taken to correspond to the degree of vertebral rotation. The least rotated (most neutral) vertebral interspace was located, and a supervised anesthesiology trainee then performed epidural catheter insertion, using a loss-of-resistance technique. Bupivacaine 0.125% with fentanyl 4 mug.mL(-1) was infused after surgery, and successful epidural placement was indicated by the presence of effective analgesia and loss of sensation to cold stimuli. In ten patients, the neutral space could be identified, while in one, the least rotated space was measured at 15 degrees from the horizontal. Epidural catheterization was successful in eight of 11 patients at the identified level. In two other patients, the space above was employed. The information was described as helpful in seven patients. We conclude that ultrasonography may have a potential role to facilitate insertion of epidural catheters in patients with scoliosis.
Article
Successful thoracic epidural analgesia depends on the sensory blockage of specific dermatomes following appropriate placement of the epidural catheter. This study aimed to ascertain how accurately anaesthesiologists identify thoracic intervertebral spaces, and whether counting from the prominent vertebra is easier than using the iliac crest as an anatomical landmark. Five anaesthesiologists attempted to locate one out of five consecutive intervertebral spaces (Th7-Th8 to Th11-Th12) on patients referred for magnetic resonance imaging of the vertebral column. The intended thoracic interspace and the counting reference point (C7-Th1 or L3-L4) were marked with oil capsules. The body mass index, gender and position of the patient were recorded. The exact capsule positions were determined by a radiologist after the study. In 92 patients, 26.7% of the thoracic interspaces were correctly identified. The counting reference point was the only variable studied with a significant influence on error. The accuracy increased when the iliac crest was used as an anatomical landmark rather than the prominent vertebra (odds ratio, 0.29). The majority (76.4%) of all the incorrectly placed capsules were found cephalad to the intended level. We recommend that the caudal of two to three possible interspaces should be used when placing an epidural catheter in the thoracic spine. Because of the inaccurate localization of the thoracic intervertebral spaces, documentation should state the site of puncture as being in the upper or lower thoracic spine instead of claiming to be in an exact interspace.
Article
A spinal block was performed in a post-laminectomy patient, using both ultrasound imaging and X-ray imaging. Ultrasound imaging clearly identified the L3/4 intervertebral level, the spinal canal, the corpus vertebrae, and the dura mater. Using ultrasound imaging, we measured the distance from the skin surface to the dura mater (39 mm). A 25-G needle for the spinal block was accurately advanced into the spinal canal with the use of X-ray imaging (43 mm from the skin to the subarachnoid space). We report here that ultrasound imaging was useful for performing a spinal block in a post-laminectomy patient in whom there was anatomical change around the spine.
Article
The aim of this study was to describe a sonographically guided ilioinguinal nerve block in adults. We developed a useful step-by-step technique of sonographically guided ilioinguinal nerve block based on visualization of abdominal muscles, fascial planes, and the branch of the deep circumflex iliac artery. We performed 9 sonographic examinations with subsequent blockade of the ilioinguinal nerve. All injections resulted in a clinically successful sensory block. This technique is reliable and reproducible. The block is achievable by a low-volume local anesthetic injection. Visualization of the intestines and blood vessels in the abdominal wall may help prevent an inadvertent injury.
Article
This study was conducted to assess the ultrasound's (US's) ability to identify pertinent landmarks for lumbar puncture (LP) in patients of various body mass indices (BMIs) and establish spatial relationships of pertinent LP landmarks across BMIs. In this institutional review board-approved cross-sectional study, we calculated the BMIs of eligible patients and then categorized them as normal (BMI < or =24.9), overweight (BMI 24.9-30), or obese (BMI > or =30). We recorded the difficulty in palpating traditional LP landmarks. Identification and measurement of the spatial relationships of the sacrum; spinous processes of lumbar vertebrae L3, L4, and L5; ligamentum flavum; and the spinal canal by US was attempted. Successful identification of pertinent structures (L4-L5 spinous processes and the spinal canal) occurred in 100% of patients with normal BMI, 95% of those who were overweight, and 74% of those who were obese (P = .011). Difficulty in palpating landmarks was noted in 5% of patients with normal BMI, 33% of those who were overweight, and 68% of those who were obese (P < .0001). In subjects with difficult-to-palpate landmarks, US identified pertinent structures in 16 of 21 (76%; 95% confidence interval, 53-92). The average distance from skin to ligamentum flavum was 44 mm in those with normal BMI, 51 mm in those who were overweight, and 64 mm in those who were obese (P < .00001); measurements between spinous processes did not vary by BMI. Overall, there was a moderate correlation (0.62) between BMI and the distance from skin to ligamentum flavum. The usefulness of US in identifying structures for LP is inversely related to BMI. Even with this limitation, US is still able to identify obese patients' pertinent landmarks almost 75% of the time. In addition, US may be helpful in identifying pertinent structures for LP in those patients with difficult-to-palpate landmarks. In patients who were obese with structures not palpable by hand or identifiable by US, other modalities should be considered.
Article
Ultrasound imaging of the spine has recently been proposed to facilitate identification of the epidural space. In this study, we assessed the accuracy and precision of the transverse approach, using a "single-screen" method, to facilitate labor epidurals. We enrolled 61 patients requesting labor epidurals. Ultrasound imaging (transverse approach, 2-5 MHz curved array probe) identified the midline, the intervertebral space, and the distance from the skin to the epidural space (ultrasound depth/UD). During the epidural puncture, we recorded the success of the insertion point, and measured the distance to the epidural space to the nearest half-centimeter of the marked Tuohy needle (needle depth/ND). We calculated the agreement between UD and ND by the concordance correlation coefficient and Bland-Altman analysis with 95% limits of agreement. The average maternal age was 33 +/- 4.6 yr, body mass index 29.7 +/- 4.8, UD 4.66 +/- 0.68 cm, and ND 4.65 +/- 0.72 cm. The success of the insertion point was 91.8%, with no need to redirect the needle in 73.8% of the patients. The concordance correlation coefficient between UD and ND was 0.881 (95% CI 0.820-0.942). The 95% limits of agreement were -0.666 to 0.687 cm. We found a good level of success in the ultrasound-determined insertion point, and very good agreement between UD and ND. This suggests that our proposed ultrasound single-screen method, using the transverse approach, can be a reliable guide to facilitate labor epidural insertion.
Article
The Episure AutoDetect syringe, a spring-loaded syringe, is a new loss-of-resistance syringe with an internal compression spring that applies constant pressure on the plunger. In this pilot study, we compared the spring-loaded syringe with the standard glass syringe for identification of the epidural space during initiation of epidural analgesia in parturients. The primary outcome was the incidence of failed epidural analgesia. Three-hundred and twenty-five women were enrolled. Eight residents performed 291 procedures (90%) and two attendings performed 34 procedures (10%). Epidural analgesia failed in five subjects in the glass syringe group and in no subject in the spring-loaded syringe group (P = 0.025).
Article
Regional anesthesia is currently the gold standard of practice for pain control in obstetrics. Failures and complications of regional anesthesia can be related to many causes, one of the most important being the blind nature of such techniques. The practice of epidurals and spinals relies primarily on the palpation of anatomic landmarks that are not always easy to find. Ultrasound has recently been introduced into clinical anesthesia to facilitate lumbar spinals and epidurals. The use of preprocedure ultrasound imaging or, eventually, real-time ultrasound guidance should improve not only clinical practice, but also teaching. This article describes the techniques, challenges, and benefits related to the use of ultrasound in guiding lumbar spinals and epidurals.
Paramedian access to the epidural space: The optimum window for ultrasound imaging
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Ultrasound imaging facilitates localization of the epidural space during combined spinal and epidural anesthesia
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