Ultrasound imaging in cadavers: training in imaging for regional blockade at the trunk

PURPOSE: The unique strategy of using cadaveric models for teaching ultrasound-guided blocks has been described for blocks of the upper and lower extremities. This report considers the parallels between cadaveric and live imaging relevant to scanning of the trunk. The inter-individual variation between subjects (particularly for epidural blocks) is also considered, for practicing ultrasound-guided or supported trunk and central neuraxial techniques. TECHNICAL FEATURES: Ultrasound images using a portable machine C60 5-2 MHz curved array probe or HFL38 13-6 MHz linear array probe were obtained from scanning the trunk of a male adult cadaver, and were compared with ultrasound and magnetic resonance images from an adult male volunteer. OBSERVATIONS: Ultrasound imaging at the midline of the spine in the transverse/coronal plane provided an overview of the vertebral column, while scanning in a medial-to-lateral direction using longitudinal/sagittal plane sequentially localized the spinous, articular and transverse process. At the thoracic spine, further lateral longitudinal scanning will identify costal structures with the rib necks alternating with the hyperechoic ligamentous tissue of the costovertebral joints. Ultrasound imaging in the live subject in the paramedian longitudinal plane could be used at the thoracic and lumber spinal levels to capture the optimal ultrasound window of the epidural space. Imaging in the cadaver, especially when viewing the epidural space, is primarily limited by the tissue rigidity and lack of spine flexibility. CONCLUSION: Cadavers may provide viable training options for practicing ultrasound imaging and real-time ultrasound needle guidance for nerve blocks at the trunk and epidural space. The training can be performed in a stress-free pre-clinical environment without time constraints and the potential for patient discomfort.     

The anatomy of the thoracic spinal canal investigated with magnetic resonance imaging (MRI)

BACKGROUND AND OBJECTIVES: Anesthesiologists are reluctant to consider higher levels for spinal anesthesia, largely due to direct threats to the spinal cord. The goal of this study is to investigate, with magnetic resonance imaging (MRI), the distances between the relevant structures of the spinal canal (spinal cord, thecal tissue, etc.) to determine modal anatomical positions for neuraxial anesthesia. METHOD: A group of 19 patients were imaged with an MRI scanner in supine position. Medial sagittal slices of the thoracic and lumbar spine were measured for the relative distances between anatomical structures, including epidural space, dura, and spinal cord. RESULTS: The posterior dura - spinal cord distance is significantly greater in the middle thoracic region than at upper and lower thoracic levels (e.g. T6 9.5 +/- 1.8 mm, T12 3.7 +/- 1.2 mm, p < 0.001, T1 4.7 +/- 1.7 mm, p < 0.001). There is variation in modal distances between the structures important for neuraxial anesthesia, at different levels of the spinal canal. CONCLUSIONS: The spinal cord tends to follow the straightest line through the imposed geometry of the spine. Considering the necessary angle of entry of the needle at mid-thoracic levels, there is relatively (more than at upper thoracic and lumbar levels) substantial separation of cord and surrounding thecal tissue. Anesthesiologists perform spinal blockades up to the L2-L3 interspace, but avoid higher levels for fear of neurological damage. The information that there is substantially more space in the dorsal subarachnoid space at thoracic level, might lead to potential applications in regional anesthesia. In contrast, the cauda equina sits more dorsally in the lumbar region.     

Ultrasound-guided epidural catheter insertion in children

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.     

Combined use of neuraxial and general anesthesia during major abdominal procedures in neonates and infants

With the advent of ultrasound and improvements in equipment, the applications of regional anesthesia in the pediatric population have continued to expand. Although frequently used for postoperative analgesia or as a means of avoiding general anesthesia in patients with comorbid conditions, the adjunctive use of regional anesthesia during general anesthesia may effectively decrease the intraoperative requirements for intravenous and volatile agents, thereby providing a more rapid awakening and earlier tracheal extubation. More recently, the limitation of the requirements for volatile and other anesthetic agents may be desirable, given concerns regarding the potential impact of these agents on neurocognitive outcome in neonates and infants. Several authors have demonstrated the potential utility of combining a neuraxial technique (spinal or epidural anesthesia) with general anesthesia in neonates and infants undergoing intraabdominal procedures. We review the literature regarding the combined use of neuraxial and general anesthesia in neonates and infants during major abdominal surgery, discuss its potential applications in this population, and review the techniques of such practice.     

Paramedian access to the epidural space: the optimum window for ultrasound imaging

STUDY OBJECTIVE: To establish a useful ultrasonic approach to the epidural space so as to optimize pre-puncture diagnostics. DESIGN: Prospective study. SETTING: University clinic. PATIENTS: 60 participants (19 to 34 years of age), 40 healthy volunteers (20 male, 20 female) and 20 parturients. INTERVENTIONS: Ultrasound scanning of the lumbar spine was performed at the L(3)-L(4) vertebral interspace. Three ultrasound planes were employed: the transverse, median, and paramedian longitudinal approaches. MEASUREMENTS: We compared the width of the ultrasound-permeable area in the median and paramedian planes and assessed the visibility of the epidural space and its surrounding structures. MAIN RESULTS: In the paramedian plane, the permeable window was larger (p < 0.001) than in the median approach. The visibility of the ligamentum flavum (p < 0.0001), dura mater (p < 0.0001), and cauda equina (p < 0.0001) was significantly higher. Pulsation of epidural vessels could be observed more frequently (p < 0.0001) in the paramedian plane. CONCLUSIONS: The longitudinal paramedian plane provided information about the epidural space depth in excellent imaging quality. The additional information might be beneficial in epidural anesthesia and in other clinical specialties (e.g., neurosurgery, trauma care).     

Locating the epidural space in obstetric patients—ultrasound a useful tool: Continuing Professional Development

Purpose

The objective of this continuing professional development module is to describe the role of ultrasound for spine demarcation before placement of neuraxial blocks and to provide a comprehensive systematic approach towards ultrasound scanning in obstetric patients.

Principal findings

Ultrasound imaging of the lumbar spine has been shown to be effective in improving the success rate of neuraxial blocks in obstetric patients. The success rate of ultrasound-guided epidural insertions at first attempt was found to be 30-60% greater when compared with the traditional epidural method. Pre-puncture ultrasound scanning can provide reliable and accurate information on several critical aspects needed for successful epidural placement, such as the interspace level, the midline of the spine, the optimal puncture point, the optimal angle for needle insertion, and the depth to the epidural space. Ultrasound scanning of the lumbar spine can generate images in two distinct patterns — one in the transverse plane represented by a “flying bat” and the other in the paramedian longitudinal plane represented by a “saw-tooth” configuration. Both approaches allow the visualization of the ligamentum flavum and the dura mater in addition to other adjacent bony landmarks. A stepwise scanning approach can serve as a useful guide to facilitate the successful placement of epidural needles in patients with both normal and abnormal spinal anatomy.

Conclusions

Incorporating the use of lumbar spine ultrasound scanning into day-to-day clinical practice may improve the ease of performing epidurals as well as add to patient safety and comfort.     

Thoracic epidural anesthesia in the perioperative period

Thoracic epidural anesthesia and analgesia is a valuable tool in the perioperative period. Successful thoracic epidural catheter placement requires a thorough knowledge of anatomy and its role in the performance of thoracic epidural block. The paramedian approach in the mid-thoracic region (T5-8) makes use of definitive bony landmarks to facilitate successful thoracic epidural space identification. In properly trained hands using carefully defined endpoints, potential risks and complications of thoracic epidural placement are minimized.The physiologic response produced by thoracic epidural drug administration differs from lumbar epidural administration. This must be taken into consideration when dosing the catheter with opioids or local anesthetics. When used appropriately, thoracic epidural drug administration provides high quality anesthesia and postoperative analgesia, and has favorable effects on postoperative outcome. Copyright 2002, Elsevier Science (USA). All rights reserved.     

Some open questions in pediatric regional anesthesia

The aim of the paper is to review the literature concerning 4 unanswered or debatable questions concerning the practice of regional anesthesia in pediatric patients. The published material concerning the 4 selected topics is reviewed, namely importance of ropivacaine, preoperative coagulation screening tests, hemodynamic stability following neuraxial blocks and prevention/treatment of post-dural puncture headache. Of the 4 questions considered in this article, 3 can be reasonably answered in a consensual way. Ropivacaine has limitations for single shot procedures in infants but its advantages for continuous infusions are significant in comparison with those of bupivacaine. Preoperative coagulation screening tests are not necessary, even not useful in children when clinical history is not suggestive of coagulation disorders, with the notable exception of neonates and prematurely born infants less than 45 weeks of post-conceptual age. The long established hemodynamic stability following neuraxial blocks results from well equilibrated compensatory mechanisms which may not be functional in children with preoperative hemodynamic instability or anomalies of the regional blood flow distribution. Finally, even though the post-dural puncture headache is not frequent in children, its management still remains difficult and no definitive recommendation can be currently made in case of inadvertent dural puncture during an attempted epidural anesthesia in children.     

Efficacy of the Epidural Positioning Device® in optimizing the acoustic target window for neuraxial needle placement in term pregnancy

BackgroundNeuraxial 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.ObjectivesOur 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).MethodsLumbar 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.ResultsThere 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).ConclusionAlthough the application of an EPD did not improve the paramedian acoustic target area in term parturients, greater patient comfort might facilitate needle placement.     

Spread of local anaesthetic solution in epidural space visualisation with ultrasound in single shot caudals

Background: Ultrasonography is becoming an important adjunct in paediatric neuraxial blockade. Ultrasound guidance helps in visualisation of relevant neuraxial structures, predicting depth of epidural space from skin, reduction in bony contact and faster epidural placement. The visibility of neuraxial structures declines in patients as age increases. To date, there are no studies looking at the extent of spread of local anaesthetic solution in the epidural space and its correlation to the volume used, under ultrasound guidance. We report the results of our audit on spread of local anaesthetic solution in the epidural space in single shot caudal blocks. This abstract is based on the first 17 patients, the presentation will be based on all 50 patients. Methods: This audit was approved by the local audit committee. We aimed to follow the extent of the spread of local anaesthetic within the epidural space with real time ultrasonography. Patients were selected when the planned anaesthetic included a single shot caudal block. The anaesthetists performing the anaesthetic and the caudal block consented to our ultrasound visualisation. All patients were below 5 years of age. No attempt was made to standardise the technique, the dose, or the speed of injection. After the placement of the caudal cannula by the primary anaesthetist involved in patient care, a separate anaesthetist, experienced in using ultrasound, visualised the neuraxial structures and subsequent spread of the local anaesthetic solution with real time ultrasound. The spread was followed during the injection and for 10 s after the completion of the injection. A 5 cm 7.5–12 MHz linear array was used longitudinally with either midline or paramedian approach. Results: We are reporting the preliminary results from 17 patients. Patients were aged between 1 day and 1 year 10 months. They weighed between 3.3 kg and 14.6 kg. Either 22 gauge Jelco or Abbocath were used to perform the procedure; 0.25% or 0.20% L‐bupivacaine was used on all occasions. The volume administered per kg ranged between 0.33 and 1.27 ml. The visibility of neuraxial structures was good on all occasions. On calculating the Spearmans correlation coefficient, the extent of spread of local anaesthetic in the epidural space was positively correlated with the volume used by a correlation coefficient of 0.64, with a P value of 0.008. The postoperative pain score in recovery was 0 in 16 out of the 17 cases. The one failure occurred when the observed spread would not have been expected to provide analgesia for the performed operation. Conclusions: Among children below 5 years of age, there seems to be a positive correlation between the volume of local anaesthetic injected into the epidural space and the extent of its spread. This needs to be further investigated by a prospective randomised control trial. The utility of real time ultrasound to allow a reliable achievement of a desired level of sensory block, should be investigated i.e, whether the volume used in achieving a desired level of local anaesthetic spread, as guided by ultrasound, provides superior analgesia and fewer adverse effects compared with the volume calculated using the Armitage regimen. References 1 Rapp HJ, Folger A, Grau T. Ultrasound guided epidural catheter insertion in children. Anesth Analg 2005; 101 : 333–339. 2 Willschke H, Marhofer P, Bosenberg A, et al. Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss of resistance technique. Br J Anaesth 2006; 97 : 200–207. 3 Marhofer P, Bosenberg A, Sitzwohl C et al. Pilot study of neuraxial imaging by ultrasound in infants and children. Pediatr Anesth 2005; 15 : 671–676.     

Epidural catheter placement in neonates: sonoanatomy and feasibility of ultrasonographic guidance in term and preterm neonates

BACKGROUND: We report the first prospective sonoanatomic study in neonates with the aim to perform ultrasonographic-guided epidural catheter placement in this age group. METHOD: One hundred forty-five neonates with a body weight < or =4 kg (0.53-4 kg) were included in this prospective study. The study was divided into 3 consecutive parts. In the first part, the neuraxial sonoanatomy of 60 neonates was evaluated. In the second part, 50 neonates scheduled for major abdominal surgery were enrolled. In this part, the depth of the ligamentum flavum measured with ultrasound was matched up to the depth evaluated clinically with the loss-of-resistance technique. In the third part, ultrasonographic epidural catheter placement was performed in 35 neonates weighing between 620 g and 4 kg. RESULTS: The ligamentum flavum, the dura mater, and the termination of the spinal cord could be identified in all patients. The first part showed a good correlation between body weight and depth of the ligamentum flavum. The median termination of the spinal cord corresponded to vertebral level L2. The second part confirmed a good correlation between depth of the ligamentum flavum evaluated clinically and the depth predicted with ultrasound. Finally, real-time ultrasound-guided epidural placement was possible in all 35 neonates. CONCLUSION: Ultrasound examination of the spinal cord anatomy provides valuable information for epidural catheter placement in neonates. Ultrasonography enables a real-time identification of the tip of the needle within the epidural space and a visualization of the spread of local anesthetic in these patients.     

Depth of the thoracic epidural space in paramedian approach

STUDY OBJECTIVE: To define the depth of the thoracic epidural space in the paramedian axis. DESIGN: Retrospective study. SETTING: Operating room of a tertiary care medical center. PATIENTS: Nine hundred ninety-eight consecutive adults scheduled for elective major cardiothoracic/abdominal surgery and postoperative thoracic epidural pain control. INTERVENTIONS: The thoracic epidural pain control was accomplished via paramedian approach at indicated levels in 977 of 998 patients with uniform and well-standardized technique routinely performed in this institute. MEASUREMENTS: The depth of the epidural space, defined as the distance from the needle tip just penetrating the epidural layer to the overlying skin, was measured by directly checking the length markers displayed on the needle. Association between demographic variables and epidural depths at different thoracic levels was analyzed. MAIN RESULTS: The mean thoracic epidural depth was (mean+/-SD) 5.11+/-0.94 cm, which was positively correlated with the body weight (regression coefficient=0.039, P<.001) and body mass index but was unrelated to sex, age, or body height. On stepwise linear multivariate regression analysis, each 10 kg of increase in body weight would result in a 0.39-cm increase in the depth. Besides, this paramedian depth was 0.34 cm longer at upper thoracic levels (T9 and upper) than that at lower levels (T10 and lower, P<.001). CONCLUSIONS: Body weight, body mass index, and anatomical levels determine the paramedian thoracic epidural depth. The greater the patient's weight and the higher the puncture level, the deeper the thoracic epidural space from the body surface.     

Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss-of-resistance technique

Background. We report a prospective, randomized study to evaluateultrasound guidance for epidural catheter placement in children0–6 yr of age. Methods. Epidural catheters were placed at lumbar or thoraciccord levels in 64 children undergoing major surgery, using eitherultrasonography or loss-of-resistance (LOR) for guidance. Usinga 5–10 MHz linear ultrasound probe, the neuraxial structureswere identified, the skin-epidural depth and epidural spacewas measured, the advancing epidural catheter visualized, andthe spread of local anaesthetic verifying catheter positionwas confirmed. Epidural placement procedures were analysed forbone contacts and speed of execution. Children under 6 monthswere analysed separately. Results. Epidural placement involved bone contacts in 17% ofchildren in the ultrasound group and 71% of children in theLOR group (P<0.0001). Epidurals were executed more swiftlyin the ultrasound group [162 (75) s vs 234 (138) s; P<0.01].Children under 6 months revealed a 0.9 correlation between skin-epiduraldepth and body weight. Conclusions. Ultrasonography is a useful aid to verify epiduralplacement of local anaesthetic agents and epidural cathetersin children. Advantages include a reduction in bone contacts,faster epidural placement, direct visualization of neuraxialstructures and the spread of local anaesthetic inside the epiduralspace. Ultrasound guidance requires additional training andgood manual skills, and should only be used once experiencein ultrasound-guided techniques of regional anaesthesia hasbeen acquired.     

Intervertebral epidural anesthesia in 2,050 infants and children using the drip and tube method

BACKGROUND AND OBJECTIVES: Pediatric epidural anesthesia has increased in popularity in the last 2 decades, but its success rate and the frequency of complications has not been fully elucidated. We therefore reviewed our experience with 2,050 cases of epidural anesthesia in infants and children. METHODS: We recorded the number of attempts at epidural space location, complications, and effectiveness in 2,050 cases of single-shot sacral intervertebral, lumbar, and thoracic epidural anesthesia. We used the drip and tube method for identification of the epidural space and administration of local anesthetic solution. RESULTS: The overall rate of successful epidural block and epidural space location on the first attempt was 96.4% and 89.8%, respectively. Complications included uncomplicated dural penetration (0.54%), spinal anesthesia (0.05%), bloody tap (0.34%), and intravascular injection (0.20%). Complications were more frequent in patients 相似文献   

Ultrasonography of the adult thoracic and lumbar spine for central neuraxial blockade

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.     

Thoracic epidural catheters placed by the caudal route in infants: the importance of radiographic confirmation

BACKGROUND: Cephalad advancement of epidural catheters to the thoracic region via the caudal route has been shown to be feasible in neonates and small infants. This has allowed many young infants to receive thoracic level epidural analgesia with dilute local anaesthetic solutions using the simpler caudal approach. Since radiographic confirmation of the catheter tip is routine at this institution, we wished to determine how often radiographic studies led to adjustment or replacement of the epidural catheter. METHODS: After institutional review board approval, we retrospectively reviewed the medical records of neonates and infants less than 6 months of age who had thoracic or lumbar epidural analgesia via the caudal route between August 1995 and January 2000. Demographic data were recorded, including age, weight and type of surgery. The epidural catheter type, tip location by radiograph and any manipulation of the catheter after the radiograph were also noted. RESULTS: During the study period, a total of 115 infants were identified as having received caudal placement of a thoracic catheter. Radiographic studies were available for 86 of these infants. The position of 28 (32%) of the epidural catheters was considered to be inadequate after review of the confirmatory radiograph. Ten of these catheters were determined to be in the high thoracic or cervical region and were pulled back to the desired level. Seventeen of these catheters were coiled in the lumbosacral area and 15 of these were replaced at an adequate level. One catheter was found to be outside the epidural space in the presacral area. No correlation could be found between age, weight, type of catheter or type of surgery and the need for catheter manipulation. CONCLUSIONS: Even in young infants, radiographic determination of the catheter tip appears warranted when thoracic catheters are placed via the caudal route.     

Review article: neuraxial analgesia in neonates and infants: a review of clinical and preclinical strategies for the development of safety and efficacy data

Neuraxial drugs provide robust pain control, have the potential to improve outcomes, and are an important component of the perioperative care of children. Opioids or clonidine improves analgesia when added to perioperative epidural infusions; analgesia is significantly prolonged by the addition of clonidine, ketamine, neostigmine, or tramadol to single-shot caudal injections of local anesthetic; and neonatal intrathecal anesthesia/analgesia is increasing in some centers. However, it is difficult to determine the relative risk-benefit of different techniques and drugs without detailed and sensitive data related to analgesia requirements, side effects, and follow-up. Current data related to benefits and complications in neonates and infants are summarized, but variability in current neuraxial drug use reflects the relative lack of high-quality evidence. Recent preclinical reports of adverse effects of general anesthetics on the developing brain have increased awareness of the potential benefit of neuraxial anesthesia/analgesia to avoid or reduce general anesthetic dose requirements. However, the developing spinal cord is also vulnerable to drug-related toxicity, and although there are well-established preclinical models and criteria for assessing spinal cord toxicity in adult animals, until recently there had been no systematic evaluation during early life. Therefore, in the second half of this review, we present preclinical data evaluating age-dependent changes in the pharmacodynamic response to different spinal analgesics, and recent studies evaluating spinal toxicity in specific developmental models. Finally, we advocate use of neuraxial drugs with the widest demonstrable safety margin and suggest minimum standards for preclinical evaluation before adoption of new analgesics or preparations into routine clinical practice.     

Thoracic epidural anesthesia for bilateral reduction mammoplasty in a patient with Klippel-Feil syndrome

General anesthesia is best avoided in cases of Klippel-Feil syndrome where tracheal intubation is potentially difficult. The syndrome features severe abnormalities of the neck and upper thoracic spine, which may also lead to difficulties with neuraxial blockade. We describe the use of epidural anesthesia for bilateral reduction mammoplasty in a patient with this condition.     

Epidural anesthesia in three parturients with lumbar tattoos: a review of possible implications

PURPOSE: To discuss the possible ramifications of neuraxial analgesia and anesthesia in women with tattoos involving their midline lumbar area. CLINICAL FINDINGS: Recently the authors have received requests for epidural anesthesia in three women with tattoos over the midline of their lumbar spine. In one patient the tattoo covered her entire back. In the other two, it was possible to locate a lumbar interspace that did not have tattoo pigment in the overlying skin. All three women received uneventful epidural analgesia. A Medline and EMBASE search for relevant publications using the keywords: epidural, spinal, tattoos, tattooing, complications did not find any reports of complications from inserting a needle through a tattoo. As none were found, the literature on tattoos and on coring with neuraxial anesthesia was reviewed to see if neuraxial anesthesia might be problematic if the needle passed through the tattoo. Coring is a complication of neuraxial anesthesia that may lead to epidermoid tumours in the subarachnoid space. Theoretically, a pigment-containing tissue core from a tattoo could be deposited into the epidural, subdural or subarachnoid spaces, leading to later neurological complications. CONCLUSIONS: There is no information in the literature about possible risks from inserting needles through tattoos during the performance of neuraxial anesthesia. This report discusses the possible implications.     

Neurologic complications of central neuraxial blocks

Central neuraxial blocks, which are associated with a low incidence of complications, are safe. When complications do occur, however, the resulting morbidity and mortality is considerable. The reported incidence of complications in all series is under 4 per 10000 patients, but given the absence of formal registries and notification procedures, which have legal implications, the real rate of occurrence of these rare events is uncertain. We searched the literature through PubMed and the Cochrane Plus Library for a 5-year period, using the search terms epidural anesthesia AND safety, spinal anesthesia AND safety, complications AND epidural anesthesia, complications AND spinal anesthesia, neurologic complications AND epidural anesthesia, and neurologic complications AND spinal anesthesia. Neuraxial injury after a central blockade may be the result of anatomical and/or physiological lesions affecting the spinal cord, spinal nerves, nerve roots, or blood supply. The pathophysiology of neuraxial injury may be related to mechanical, ischemic, or neurotoxic damage or any combination. When a complication occurs, factors related to the technique will have interacted with pre-existing patient-related conditions. Various scientific societies have published guidelines for managing the complications of regional anesthesia. Recently published clinical practice guidelines recommend ultrasound imaging as a useful tool in performing a central neuraxial block.