• Epidural catheter placement
• Neuraxial block
• Thoracic epidural analgesia
• Thoracic surgery
• Ultrasound guidance

• intrathecal block
• labor analgesia
• obese parturients

• back pain
• chronic pain
• injections, spinal
• pain management

• Humans
• Epidural Space/diagnostic imaging
• Prospective Studies
• Male
• Injections, Epidural/methods
• Female
• Middle Aged
• Magnetic Resonance Imaging/methods
• Lumbar Vertebrae/diagnostic imaging
• Adult
• Aged
• Steroids/administration & dosage
• Ultrasonography, Interventional/methods
• Ultrasonography/methods
• Low Back Pain/drug therapy
• Low Back Pain/diagnostic imaging
• Fluoroscopy/methods

• Obstetrics
• REGIONAL ANESTHESIA
• Ultrasonography

• Pregnancy
• Female
• Humans
• Anesthesia, Spinal/methods
• Ultrasonography, Interventional/methods
• Spinal Puncture/methods
• Ultrasonography
• Obesity/complications
• Obesity/diagnosis
• Palpation

• randomized controlled trials
• anatomy
• health care
• medical research

• Pregnancy
• Humans
• Female
• Ultrasonography, Interventional/methods
• Anesthesia, Spinal/methods
• Spinal Puncture
• Analgesia, Epidural/methods
• Palpation

• Analgesia
• Anesthesia
• Difficult airway
• Obesity
• Pregnancy

• Neuraxial anesthesia
• Pregnancy
• Regional anesthesia
• handheld ultrasound
• portable ultrasound
• ultrasound guided neuraxial anesthesia

• Anesthesia, spinal
• Spinal column
• Ultrasonography

• Humans
• Sitting Position
• Prospective Studies
• Lumbar Vertebrae/diagnostic imaging
• Lumbosacral Region/diagnostic imaging
• Anesthesia, Spinal

• analgesia
• anesthesia
• caudal
• epidural
• lumbar
• neuraxial
• spinal
• spine
• ultrasound

• Analgesia
• Anesthesia
• Cesarean delivery
• Labor
• Obesity
• Pregnancy

• Spinal needle depth
• Stocker’s formula
• subarachnoid space
• ultrasonography

• Cesarean section
• Jacoby’s line
• Lateral decubitus position
• Neuraxial anesthesia
• Tuffier’s line

Conducting spinal anaesthesia in patients with elevated body mass index is commonly difficult, yet there are no guidelines to direct best practice. Landmark techniques are sometimes insufficient, leading to increased failure rates and suboptimal patient outcomes. Although ultrasound-guided techniques are now considered standard care for central venous access and regional anaesthesia, there has been relatively sparse uptake of this widely available resource for central neuraxial block, despite evidence of its efficacy.

This article outlines a successful case of ultrasound-assisted spinal anaesthesia, after landmark techniques failed, in conjunction with a combined spinal-epidural kit. This unique combination of techniques has not been published as an amalgamated rescue strategy for difficult spinal anaesthesia. This article adds to current evidence by highlighting the potential benefits of combining these techniques into a novel approach either when difficulties are expected or as a rescue technique after failed landmark-based attempts.

• anaesthesia
• obesity (nutrition)
• orthopaedic and trauma surgery
• sleep disorders (respiratory medicine)
• ultrasonography

For parturients with paroxysmal uterine contraction pain, rapid analgesia is needed. We used preprocedure ultrasound imaging combined with the palpation technique in epidural analgesia for labor, and evaluated the usefulness of this technique in epidural labor analgesia.

To evaluate the usefulness of preprocedure ultrasound imaging in epidural analgesia for labor.

In this prospective randomized observational study, 72 parturients were assigned to two groups (combined or palpation group). The target interspace of all parturients was first identified by the palpation technique. Then in the combined group, preprocedure ultrasound imaging was used before epidural puncture. In the palpation group, only the traditional anatomical landmarks technique (palpation technique) was performed. The primary outcome was total duration of the epidural procedure (for the ultrasound group, the duration of the preprocedure ultrasound imaging was included). The secondary outcomes were the number of skin punctures, the success rate at first needle pass, the number of needle passes, the depth from the skin to epidural space, and the complications of the procedure.

Total duration of the epidural procedure was similar between the two groups (406.5 ± 92.15 s in the combined group and 380.03 ± 128.2 s in the palpation group; P = 0.318). A significant improvement was demonstrated for epidural puncture and catheterization in the combined group. The number of needle passes was 1.14 in the combined group and 1.72 in the palpation group (P = 0.001). The number of skin puncture sites was 1.20 in the combined group and 1.25 in the palpation group (P = 0.398). The success rate at first needle pass was 88.89% in the combined group and 66.67% in the palpation group (P = 0.045).

This study demonstrated that the total duration of epidural procedures with preprocedure ultrasound imaging combined with the palpation technique was not longer than the traditional anatomical landmarks technique, which were performed by six experienced anesthesiologists in parturients with normal weights undergoing labor analgesia.

• Preprocedure ultrasound imaging
• Epidural puncture
• Epidural catheterization
• Palpation technique
• Labor analgesia

Lumbar epidural catheter insertion is conventionally performed by anesthesia residents by palpation of anatomical landmarks with relatively blind localization of epidural space which may lead to an increase in failure rate. We aim to compare the ease of lumbar epidural catheterization using prepuncture ultrasound as guidance with that of conventional palpatory technique. Comparisons were made with reference to number of insertion attempts, total time taken for the procedure, frequency of dural puncture, and overall satisfaction score as assessed by Likert's scale.

Eighty, ASA 1-3, patients undergoing elective surgeries requiring lumbar epidural catheterization were recruited for the study. Study participants were randomized into two groups. In group P, epidural catheterization was performed using the conventional palpatory method and in group U, it was performed with the help of ultrasound determined parameters. Number of insertion attempts, total time taken for successful insertion of epidural catheter, frequency of dural puncture, and overall satisfaction of ease of insertion as determined by Likert's scale were compared between both the groups. Data were analyzed using SPSS statistical software version 17 and P value <0.05 was considered statistically significant.

The number of insertion attempts was significantly lesser in Group U (P = 0.019). The total procedure time was significantly higher in group U (P < .001). There was no significant difference in ease of insertion score, as measured by Likert's scale between both the groups (P = 0.45).

Prepuncture ultrasound guidance improves the first attempt success rate of lumbar epidural catheterization with reduced incidence of dural puncture with similar overall satisfaction score but increases the total time taken for the procedure when compared to conventional palpatory technique.

• Anesthesiology residents
• lumbar epidural
• prepuncture ultrasound

Ultrasonography can be useful to perform a lumbar neuraxial block. It aids in understanding the anatomy of the lumbar spine before the procedure. Pre-procedural ultrasound imaging provides information about the accurate intervertebral level for puncture, optimal needle insertion point, and depth of needle advancement for a successful neuraxial block. The key ultrasonographic views for lumbar neuraxial block include the transverse midline interlaminar and parasagittal oblique views. Ultrasonography can facilitate lumbar neuraxial block in difficult cases, such as the elderly, obese patients, and patients with anatomical abnormality of the lumbar spine. This review elucidates the basics of spinal ultrasonography for lumbar neuraxial block and the current evidence regarding ultrasound-guided neuraxial block in adults.

• Anesthesia, epidural
• Anesthesia, spinal
• Lumbar vertebrae
• Ultrasonography

The acupotomy is an acupuncture device recently used to stimulate lumbar vertebrae such as transverse processes (TPs) and facet joints (FJs). However, there are many organs, nerves, and blood vessels, which can lead to side effects if the needle misses the treatment target. Therefore, information regarding appropriate insertion depths, which is currently lacking, could facilitate its safe use. We retrospectively investigated the depth from the skin to the TP and FJ of the lumbar vertebrae, using magnetic resonance imaging (MRI).

This retrospective chart review was conducted at a single medical centre in Korea. From 55,129 patient records, 158 subjects were selected. Perpendicular depth from the skin to the left and right TPs and FJs was measured using T1-weighted sagittal plane MRI. Depth differences between the left and right sides were evaluated using the paired t-test and analysis of covariance (body mass index [BMI] as a covariate). The influence of BMI on depth at each location was evaluated by simple linear regression analysis.

The mean age was 43.2 years and mean BMI was 23.6 kg/m². The depth from skin to the TPs or FJs was unaffected by age, sex, or side. Mean depths (cm) were as follows: (TPs) L1 = 4.5, L2 = 4.9, L3 = 5.3, L4 = 5.7, L5 = 5.9; (FJs) L12 = 3.8, L23 = 4.0, L34 = 4.4, L45 = 4.6, L5S1 = 4.6. Depth was highly correlated with BMI at each location.

The depth of TPs and FJs adjusted for BMI can safely and effectively be used for treatment via various invasive interventions, including acupotomy treatment, in the lumbar region.

• Acupotomy
• Complementary medicine
• Lumbar spine
• MRI
• Needling depth

• Neuraxial anesthesia
• Obstetric neuraxial blockade
• Ultrasound

• Anestesia
• Anesthesia
• Epidural
• Intraoperative
• Intraoperatório
• Magnetic resonance imaging
• Peridural
• Ressonância magnética
• Ultrasound
• Ultrassonografia

• body habitus
• body mass index
• body shapes
• epidural depth
• neuraxial block

To assess the agreement between the epidural depth measured from the surgical site with the epidural depths estimated with magnetic resonance imaging (MRI) and ultrasound scanning.

Fifty patients of either sex, scheduled for L4‒5 lumbar disc surgery under general anesthesia were enrolled in this prospective observational study, and the results of 49 patients were analyzed. The actual epidural depth was measured from the surgical site with a sterile surgical scale. The MRI-derived epidural depth was measured from the MRI scan. The ultrasound estimated epidural depth was measured from the ultrasound image obtained just before surgery.

The mean epidural depth measured from the surgical site was 53.80 ± 7.67 mm, the mean MRI-derived epidural depth was 54.06 ± 7.36 mm, and the ultrasound-estimated epidural depth was 53.77 ± 7.94 mm. The correlation between the epidural depth measured from the surgical site and MRI-derived epidural depth was 0.989 (r² = 0.979, p < 0.001), and the corresponding correlation with the ultrasound-estimated epidural depth was 0.990 (r² = 0.980, p < 0.001).

Both ultrasound-estimated epidural depth and MRI-derived epidural depth have a strong correlation with the epidural depth measured from the surgical site. Preprocedural MRI-derived estimates of epidural depth are slightly deeper than the epidural depth measured from the surgical site, and the ultrasound estimated epidural depths are somewhat shallower. Although both radiologic imaging techniques provided reliable preprocedural estimates of the actual epidural depth, the loss of resistance technique cannot be discarded while inserting epidural needles.

• Labor analgesia
• Labor pain
• Neuraxial analgesia
• Nitrous oxide
• Opioids
• Pain relief in labor

• Analgesia, Epidural/methods
• Analgesia, Obstetrical/methods
• Anesthesia, Obstetrical/methods
• Anesthetics, Local/administration & dosage
• Female
• Humans
• Injections, Spinal
• Labor Pain/therapy
• Labor, Obstetric/drug effects
• Nitrous Oxide
• Pain Management/methods
• Pain Measurement/drug effects
• Patient Satisfaction
• Pregnancy
• Treatment Outcome

The aim of this study was to assess the accuracy and precision of the actual epidural depth (ND) and ultrasound (US) estimates of the distance from the skin to the epidural space in the transverse median plane (ED/TM) and paramedian sagittal oblique plane (ED/PSO) in patients who were not pregnant and who were undergoing unilateral inguinal hernia repair surgery under combined spinal epidural anaesthesia.

A total of 100 patients with the American Society of Anaesthesiology status I–III of either gender were recruited. All epidurals were inserted at the L3–4 intervertebral space, and the epidural needle was marked with a sterile marker. The ND was measured between the marker and the tip of the needle. The ED/TM and ED/PSO were assessed with a 2–5 MHz curved array probe at the L3–4 intervertebral space. The Pearson correlation coefficient and Lin’s concordance correlation coefficient were used to assess the precision and the Bland–Altman test was used to assess the 95% limit of agreement.

The ND was 48.98±6.91 mm, the ED/PSO was 48.92±6.91 mm and the ED/TM was 48.90±6.91 mm. The Pearson correlation coefficient between ND and ED/PSO was 0.995 (p<0.001) and 0.994 (p<0.001) with ED/TM. Lin’s concordance correlation coefficient for ND and ED/PSO was 0.995 (95%CI [confidence interval]: 0.992–0.997), and 0.993 for ND and ED/TM (95% CI: 0.990–0.996). The 95% limit of agreement between ND and ED/PSO was 0.70–1.37, and for ND and ED/TM, it was 0.79–1.54.

Preprocedural ultrasound (US) scanning in both planes provides reliable estimates for actual epidural depth in non-pregnant patient population.

• Epidural depth
• paramedian sagittal oblique
• transverse median
• ultrasound

This study aimed to assess the correlations of actual epidural depth (ND) and ultrasound estimated epidural depth in the paramedian sagittal oblique plane (ED/PSO) and transverse median plane (ED/TM) with the abdominal girth (AG), body mass index (BMI), and weight of patients.

One hundred and thirty patients of either sex scheduled for unilateral inguinal hernia repair were enrolled. ED/PSO and ED/TM were assessed with a 2–5 MHz curved array probe at the L3–4 intervertebral space. The epidural needle was marked with a sterile marker upon locating the epidural space. The ND was assessed by measuring the distance from the sterile marker to the tip of the epidural needle with a linear scale. Anthropometric measures of the patients were recorded.

ED/PSO was 49.6 ± 7.9 mm, ED/TM was 49.5 ± 7.9 mm, and ND was 50.0 ± 8.0 mm. AG was 99.8 ± 12.9 cm. The Pearson correlation coefficient between ND and ED/PSO was 0.997 and with ED/TM was 0.996 (P < 0.001 for both). Pearson correlation coefficients for ND with AG, BMI, and weight were 0.757, 0.547, and 0.638, respectively (P < 0.001 for all).

AG, weight, and BMI have strong correlations with ND.

• Abdominal girth
• anesthesia
• epidural
• ultrasound

• Abdomen/anatomy & histology
• Abdomen/diagnostic imaging
• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Anesthesia, Epidural/methods
• Body Mass Index
• Body Weight
• Epidural Space/anatomy & histology
• Epidural Space/diagnostic imaging
• Female
• Hernia, Inguinal/surgery
• Humans
• Male
• Middle Aged
• Ultrasonography
• Young Adult

Obesity is a significant global health problem. It results in a higher incidence of complications for pregnant women and their neonates. Cesarean deliveries are more common in obese parturients as well. The increased burden of comorbidities seen in this population, such as obstructive sleep apnea, necessitates antepartum anesthetic consultation. These patients pose unique challenges for the practicing anesthesiologist and may benefit from optimization prior to delivery. Complications from anesthesia and overall morbidity and mortality are higher in this population. Neuraxial anesthesia can be challenging to place in the obese parturient, but is the preferred anesthetic for cesarean delivery to avoid airway manipulation, minimize aspiration risk, prevent fetal exposure to volatile anesthetic, and decrease risk of post-partum hemorrhage from volatile anesthetic exposure. Monitoring and positioning of these patients for surgery may pose specific challenges. Functional labor epidural catheters can be topped up to provide conditions suitable for surgery. In the absence of a working epidural catheter, a combined spinal epidural anesthetic is often the technique of choice due to relative ease of placement versus a single shot spinal technique as well as the ability to extend the anesthetic through the epidural portion. For cesarean delivery with a vertical supraumbilical skin incision, a two-catheter technique may be beneficial. Concern for thromboembolism necessitates early mobilization and a multimodal analgesic regimen can help accomplish this. In addition, thromboprophylaxis is recommended in this population after delivery—especially cesarean delivery. These patients also need close monitoring in the post-partum period when they are at increased risk for several complications.

• cesarean delivery
• labor analgesia
• neuraxial anesthesia
• obesity

• Obese
• preprocedural ultrasound scan
• useful adjunct

• anesthesia
• regional
• sonoanatomy

• Clinical Competence
• Hospital Medicine/standards
• Humans
• Inservice Training
• Knowledge
• Lumbar Vertebrae
• Practice Guidelines as Topic
• Societies, Medical/standards
• Spinal Puncture/methods
• Spinal Puncture/standards
• Ultrasonography, Interventional/methods
• Ultrasonography, Interventional/standards

• I50 HX002263 HSRD VA
• UL1 TR001086 NCATS NIH HHS

• Lumbar Vertebrae
• Magnetic Resonance Imaging
• Ultrasonography

• Adult
• Algorithms
• Female
• Healthy Volunteers
• Humans
• Imaging, Three-Dimensional
• Lumbar Vertebrae/diagnostic imaging
• Magnetic Resonance Imaging
• Male
• Sampling Studies
• Ultrasonography

This study evaluated the efficacy of spinal anesthesia administration by resident physicians when using an ultrasound system with automated neuraxial landmark detection capabilities.

150 patients were enrolled in this trial. Anesthesiology residents placed spinals in subjects undergoing scheduled cesarean delivery using one of three techniques to identify neuraxial landmarks: palpation, ultrasound, or combined palpation and ultrasound. Ultrasound was performed using a handheld system that automatically identified neuraxial landmarks (e.g. midline, intervertebral spaces). All residents watched a 10-minute video and received 20 minutes of hands-on training prior to participating in the study. First insertion success rate was the primary end point.

Among all patients, use of ultrasound resulted in a 11% greater first-insertion success rate (RR: 1.11 [0.85–1.47], p=0.431), a 15% reduction in needle insertions (RR: 0.85, p=0.052), and a 26% decrease in needle passes (RR: 0.74, p=0.070). In obese patients of BMI ≥ 30 kg/m², use of ultrasound resulted in 26% greater first-insertion success rates (RR: 1.26, p=0.187), a 21% decrease in needle insertions (RR: 0.79, p=0.025), a 38% decrease in needle passes (RR: 0.62, p=0.030), and a 75% decrease in patients reporting neutral or low patient satisfaction with anesthesia administration (RR: 0.25, p=0.004).

Resident anesthesiologists competently utilized the ultrasound system after receiving minimal training. Technical endpoints and patient satisfaction trended towards improvement when ultrasound was used prior to spinal placement, with stronger trends observed in obese patients. Additional study is required to fully characterize the impact of the ultrasound system on clinical efficacy.

• Bone-specific imaging
• Neuraxial ultrasound
• Spinal anesthesia

• Anesthesia, Epidural/methods
• Animals
• Epidural Space
• Lasers
• Ligamentum Flavum
• Spinal Puncture/methods
• Swine

• Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
• Chang Gung Memorial Hospital, Linkou (Linkou Chang Gung Memorial Hospital)

• Epidural
• Labor analgesia
• Neuraxial
• Ultrasound

Purpose: Technology of reflectance spectroscopy incorporated with auto-fluorescence spectroscopy were employed to increase the safety of epidural placement in regional anesthesia which is generally used for surgery, epidural anesthesia, post-operative pain control and painless childbirth. Method: Ex vivo study of auto-fluorescence spectroscopy was performed for the para-vertebral tissues contained fat, interspinous ligament, supraspinous ligament and ligamentumflavum by multimode microplate reader at wavelength 405 nm for the purpose of tissue differentiation. A specially designed optic-fiber-embedded needle was employed to incorporate with both reflectance and autofluorescence spectroscopies in order to probe the epidural space as double assurance demands. In vivo study was carried out in a Chinese native swine weighted about 30 kg under intubated general anesthesia with ventilation support. The reflective (405 nm) and autofluorescence signals (λ and λ*) were recorded at 5 different sites by an oscilloscope during the needle puncture procedure from skin to epidural space in the back of the swine. Results: Study of either autofluorescence spectroscopy for tissue samples or ex vivo needle puncture in porcine trunk tissues indicates that ligmentumflavum has at least 10-fold higher fluorescence intensity than the other tissues. In the in vivo study, ligamentumflavum shows a double-peak character for both reflectance and autofluorescence signals. The epidural space is located right after the drop from the double-peak. Both peaks of reflectance and fluorescence are coincident which ensures that the epidural space is correctly detected. Conclusions: The fiber-optical technologies of double-assurance demands for tissue discrimination during epidural needle puncture can not only provide an objective visual information in a real-time fashion but also it can help the operator to achieve much higher success rate in this anesthesia procedure.

• autofluorescence
• double assurance
• epidural space
• ligmentumflavum
• optic fiber

• Body mass index
• Cesarean section
• Epidural
• Obesity
• Subcutaneous fat thickness

• Lumbar ultrasonography
• neuraxial block
• obstetric anesthesia

• analgesia
• anesthesiology
• epidural
• labor
• midline
• ultrasound

• Adult
• Analgesia, Epidural/instrumentation
• Analgesia, Epidural/methods
• Analgesics/administration & dosage
• Cohort Studies
• Epidural Space/diagnostic imaging
• Female
• Humans
• Pregnancy
• Prospective Studies
• Treatment Outcome
• Ultrasonography, Interventional/methods

• Ultrasound
• intervention
• musculoskeletal
• spine
• therapeutic

The objective of the present study was to evaluate the skin-epidural space distance as assessed by ultrasonography and conventional loss of resistance (LOR) technique and to find the correlation of epidural depth with body mass index (BMI).

Ninety-eight patients of either sex, American Society of Anesthesiology I/II, BMI <30 kg/m² requiring lumbar epidural for surgery were enrolled. The epidural space was assessed with a curvilinear ultrasound (US) probe, 2–5 MHz, in the transverse plane at L3–L4 intervertebral space. Thereafter, the epidural depth from skin was assessed with conventional LOR method while performing the epidural. The needle depth (ND) was measured using a sterile linear scale, and any change in the needle direction or intervertebral space was noted.

The patients were demographically similar. Depth of epidural space measured by US depth (UD) was 3.96 ± 0.44 cm (range 3.18–5.44 cm) and by ND was 4.04 ± 0.52 cm (range 2.7–5.7 cm). The Pearson's correlation coefficient (r) between UD and ND was 0.935 (95% confidence interval: 0.72–0.92, r² = 0.874, P < 0.001), and Bland–Altman analysis revealed the 95% limits of agreement −0.494–0.652 cm.

The present study demonstrates a good correlation between UD and ND and shows that the preprocedural US scan in transverse plane provides accurate needle entry site with a high success rate in single attempt for lumbar epidurals in patients with a BMI <30 kg/m².

• Lumbar epidural
• needle depth
• transverse plane
• ultrasound
• ultrasound depth

The role of ultrasound in the thoracic spine has been underappreciated, partly because of the relative efficacy of the landmark-guided technique and the limitation of imaging through the narrow acoustic windows produced by the bony framework of thoracic spine. The aim of this study was to make a comparison between the 12th rib and the spinous process of C7 as a landmark for effective ultrasound-guided target segment identification in the thoracic spine.

Ultrasonography of 44 thoracic spines was performed and the same procedure was carried out 1 week later again. The target segments (T3–4, T7–8, and T10–11) were identified using the 12th rib (group 1) or the spinous process of C7 (group 2) as a starting landmark. Ultrasound scanning was done proximally (group 1) or distally (group 2) toward the target transverse process and further medially and slightly superior to the target thoracic facet. Then, a metal marker was placed on the T3–4, T7–8, and T10–11 and the location of each marker was confirmed by fluoroscopy.

In the total 132 segments, sonographic identification was confirmed to be successful with fluoroscopy in 84.1% in group 1 and 56.8% in group 2. Group 1 had a greater success rate in ultrasound-guided target segment identification than group 2 (p = 0.001), especially in T10–11 (group 1, 93.2%; group 2, 43.2%; p = 0.001) and T7–8 (group 1, 86.4%; group 2, 56.8%; p = 0.002). The intrarater reliability of ultrasound-guided target segment identification was good (group 1, r = 0.76; group 2, r = 0.82), showing no difference between right and left sides. Ultrasound-guided target segment identification was more effective in the non-obese subjects (p = 0.001), especially in group 1.

Ultrasound-guided detection using the 12th rib as a starting landmark for scanning could be a promising technique for successful target segment identification in the thoracic spine.

• Nerve block
• Thoracic spine
• Ultrasonography

• Health economics
• Quality in health care
• caesarean section
• obesity

• Adolescent
• Adult
• Body Mass Index
• Cesarean Section/classification
• Cesarean Section/economics
• Cesarean Section/statistics & numerical data
• Female
• Hospitalization/statistics & numerical data
• Humans
• Middle Aged
• Obesity/epidemiology
• Operative Time
• Outcome Assessment, Health Care
• Pregnancy
• Pregnancy Complications/epidemiology
• Prospective Studies
• Risk Factors
• Young Adult

• Australian and New Zealand College of Anaesthetists (ANZCA)

• Adult
• Algorithms
• Anesthesia, Epidural/methods
• Computer Systems
• Epidural Space
• Female
• Humans
• Image Processing, Computer-Assisted/methods
• Lumbosacral Region
• Male
• Middle Aged
• Needles
• Support Vector Machine
• Ultrasonography
• Young Adult