Needle Location Research Articles

Treating primary dysmenorrhoea with acupuncture: a narrative review of the relationship between acupuncture 'dose' and menstrual pain outcomes.

A number of randomised controlled trials have been performed to determine the effectiveness or efficacy of acupuncture in primary dysmenorrhoea. The objective of this review was to explore the relationship between the 'dose' of the acupuncture intervention and menstrual pain outcomes. Eight databases were systematically searched for trials examining penetrating body acupuncture for primary dysmenorrhoea published in English up to September 2015. Dose components for each trial were extracted, assessed by the two authors and categorised by neurophysiological dose (number of needles, retention time and mode of stimulation), cumulative dose (total number and frequency of treatments), needle location and treatment timing. Eleven trials were included. Components of acupuncture dose were well reported across all trials. The relationship between needle location and menstrual pain demonstrated conflicting results. Treatment before the menses appeared to produce greater reductions in pain than treatment starting at the onset of menses. A single needle during menses may provide greater pain reduction compared to multiple needles. Conversely, multiple needles before menses were superior to a single needle. Electroacupuncture may provide more rapid pain reduction compared to manual acupuncture but may not have a significantly different effect on overall menstrual pain. There appear to be relationships between treatment timing and mode of needle stimulation, and menstrual pain outcomes. Needle location, number of needles used and frequency of treatment show clear dose-response relationships with menstrual pain outcomes. Current research is insufficient to make definitive clinical recommendations regarding optimum dose parameters for treating primary dysmenorrhoea.

“No pain, no gainz”? Performance and image-enhancing drugs, health effects and information seeking

Background: A range of indicators point to an international increase in the prevalence of performance and image-enhancing drugs (PIEDs) use, predominantly among young men. Attention to PIEDs-related benefits, adverse health effects, information and health service access are needed. Methods: A cross-sectional survey of 605 men who inject PIEDs was conducted at nine primary needle and syringe programme locations across five local health districts in Sydney. Results: Among anabolic–androgenic steroids (AAS) users (n = 564), anger, rage or irritability (27%, 95%CI: 23.4–30.6) and sexual or genital problems (26.4%, 95%CI: 22.9–30.0) were the most commonly reported adverse health effects. Taking regular, longer breaks between AAS cycles were associated with reduced reports of some adverse effects. Approaching two-thirds of participants had told a doctor about using PIEDs (63.1%, 95%CI: 59.1–67.1). However, as length of time since first injecting PIEDs increased, participants’ perceptions of doctors as reliable information sources decreased (rho = −0.10, p = 0.04). Reliance on lay information sources was very common, particularly among people who spoke languages other than English. Conclusions: This study supports providing information on cycle lengths and break periods as part of standard PIEDs-related harm reduction guidelines. Safe injecting and dosage education through peer networks or steroid clinics may be useful strategies.

Visual experiment of transient cavitating flow characteristics in the real-size diesel injector nozzle

Cavitating flow inside diesel injector nozzles affects subsequent atomization behaviors and then spray characteristics which is decisive for diesel engine performance and pollutant formation. In this paper, particular attention was focused on the transient flow characteristics in the real-size diesel nozzle. An experimental study under different pressures was conducted to analyze the evolution of cavitation inside diesel nozzle, and it was found that higher injection pressure leads to earlier cavitation inception. The bubble “suction” from orifice exit at the end of injection and the bubble “discharge” at the initial stage of the next injection were observed as well. Moreover two types of “string cavitation” were observed and the “string cavitation” as a special cavitation phenomenon which considerably boost the spray angle was investigated in details. It was found that the occurrence of “string cavitation” has a strong relationship with the location of needle, the injection pressure, and the shape of sac. Furthermore the effects of these three factors on the occurrence regularity of the “string cavitation” were also investigated.

Multi-scale RANSAC algorithm for needle localization in 3D ultrasound guided puncture surgery.

Correct localization of the needle is of vital importance to guarantee successful puncture. The complexity of real US data increases the difficulties. A multi-scale random sample consensus (MS-RANSAC) algorithm is proposed in this paper to locate the needle in complicated 3D US data. The algorithm uses the radius difference between needle and other tubular human tissues to extract the correct needle location. The performance of classic RANSAC and MS-RANSAC are compared using three different datasets. Results show that MS-RANSAC can locate needle correctly in complicated condition where classic RANSAC cannot. A parallel framework of the algorithm is designed and implemented using CUDA, making it usable in real time and online.

Acupuncture for musculoskeletal pain: A meta-analysis and meta-regression of sham-controlled randomized clinical trials.

The aims of this systematic review were to study the analgesic effect of real acupuncture and to explore whether sham acupuncture (SA) type is related to the estimated effect of real acupuncture for musculoskeletal pain. Five databases were searched. The outcome was pain or disability immediately (≤1 week) following an intervention. Standardized mean differences (SMDs) with 95% confidence intervals were calculated. Meta-regression was used to explore possible sources of heterogeneity. Sixty-three studies (6382 individuals) were included. Eight condition types were included. The pooled effect size was moderate for pain relief (59 trials, 4980 individuals, SMD −0.61, 95% CI −0.76 to −0.47; P < 0.001) and large for disability improvement (31 trials, 4876 individuals, −0.77, −1.05 to −0.49; P < 0.001). In a univariate meta-regression model, sham needle location and/or depth could explain most or all heterogeneities for some conditions (e.g., shoulder pain, low back pain, osteoarthritis, myofascial pain, and fibromyalgia); however, the interactions between subgroups via these covariates were not significant (P < 0.05). Our review provided low-quality evidence that real acupuncture has a moderate effect (approximate 12-point reduction on the 100-mm visual analogue scale) on musculoskeletal pain. SA type did not appear to be related to the estimated effect of real acupuncture.

Ultrasound Guidance for Interventional Pain Management of Lumbar Facet Joint Pain: An Anatomical and Clinical Study

Background: There is a growing trend in ultrasound use in interventional pain management. Recently, the ease of use and clinical benefits of lumbar medial branch nerve block under ultrasound guidance have been identified. Objectives: In this study, we assessed the relevant anatomy and sonoanatomy of these specific interventional techniques. We also evaluated the feasibility and success rates of ultrasound guided lumbar medial branch nerve block. Patients and Methods: Thirty patients with facet joint pain who were referred to the Akhtar hospital pain clinics between 2011 and 2012 were evaluated. Eighty-nine ultrasound-guided lumbar medial branch nerve blocks were performed. The target point for the lumbar nerve block was the cephalad margin of the transverse process groove in the vicinity of the superior articular process. C-arm fluoroscopy was performed to confirm the needle location. Pain levels were measured by a visual analog scale (0 - 10 scale), the Oswestry disability index (0 - 5 scale), and patient satisfaction scores (0 - 3 scale). The patients were followed for 6 weeks. Results: The success rate was 98% (87/89 blocks), which was due to our use of ultrasound guided needle placement for the correct positioning of the needles. The mean procedural time was 5.9 ± 1 minutes. The average time of needle insertion was 4 ± 1 minutes. The pain intensity significantly improved from an initial value of 5 to 2.8 in the final follow-up (P = 0.0001). The oswestry disability index score significantly improved from 33.9 to 18.3 in the final follow-up (P = 0.0001). Patient satisfaction significantly improved from poor satisfaction immediately after the medial branch nerve block to excellent satisfaction in the final follow-up (P = 0. 0001). Analgesic requirements were also significantly reduced after 6 weeks of follow-up (P = 0.046). Conclusion: Lumbar medial branch nerve block under ultrasound guidance was associated with high rates of treatment success and excellent treatment outcomes for facet joint pain. It is also feasible and administers no radiation. Thus, ultrasound-guided procedures can be used instead of conventional methods.

SU‐F‐T‐44: A Comparison of the Pre‐Plan, Intra‐Operative Plan, and Post‐Implant Dosimetry for a Prostate Implant Case Using Prefabricated Linear Polymer‐Encapsulated Pd‐103

Purpose:To investigate the reproducibility and limitations of Pd‐103 prostate brachytherapy using fixed length linear sources (CivaString).Methods:An LDR prostate brachytherapy case which was preplanned on MR images with prefabricated linear polymer‐encapsulated Pd‐103 sources (CivaString) was studied and compared with ultrasound based intra‐operative planning and CT based post‐implant dosimetry. We evaluated the following parameters among the three studies: prostate geometry (volume and cross sectional area), needle position and alignment deviations, and dosimetry parameters (D90).Results:The prostate volumes and axial cross sectional areas at center of prostate were measured as 41.8, 39.3 and 36.8 cc, and 14.9, 14.3, and 11.3 respectively on pre‐plan MR, inter‐op US, and post‐implant CT studies. The deviation of prostate volumes and axial cross sectional areas measured on pre‐planning MR and intra‐operative US were within 5%. 17 out of 19 pre‐planned needles were positioned within 5mm (the template grid size). One needle location was adjusted intra‐operatively and another needle was removed due to proximity to urethra. The needle pathways were not always parallel to the trans‐rectal probe due to the flexibility of CivaString. The angle of deviation was up to 10 degrees. Two pairs of needles were exchanged to better fit the length of prostate at the time of implant. This resulted in a prostate D90 of 153.8 Gy (124%) and 131.4 Gy (106.7%) for intra‐op and PID respectively.Conclusion:Preplanning is a necessary part of implants performed with prefabricated linear polymer sources. However, as is often the case, there were real‐time deviations from the pre‐plan. Intra‐op planning provides the ability conform to anatomy at the time of implant. Therefore, we propose to develop a systematic way to order extra strings of different length to provide the flexibility to perform intra‐operative planning with fixed length strands.

An Ex Vivo Phantom Validation Study of an MRI-Transrectal Ultrasound Fusion Device for Targeted Prostate Biopsy.

To evaluate the ex vivo accuracy of an MRI-TRUS fusion device for guiding targeted prostate biopsies, to identify the origin of errors, and to evaluate the likelihood that lesions can be accurately targeted. Three prostate phantoms were used to perform 27 biopsies using transperineal MRI-TRUS fusion. All phantoms underwent 3-T MRI. The prostate contour and nine lesions were delineated onto the MRI. A 3D-US dataset was generated and fused with the MRI. Per lesion, one needle was virtually planned. The postbiopsy needle location was virtually registered. The needle trajectory was marked using an MRI-safe guidewire. Postinterventional MRI was performed. The coordinates of the lesion on preinterventional MRI, the virtually planned needle, the virtually registered needle, and the marked needle trajectory on postinterventional MRI were documented and used to calculate the planning error (PE), targeting error (TE), and overall error (OE). Using the OE in the transversal plane, an upper one-sided tolerance interval was calculated to assess the likelihood that a biopsy needle was on target. In the transversal plane, the mean PE, TE, and OE were 1.18, 0.39, and 2.33 mm, respectively. Using a single biopsy core, the likelihood that lesions with a diameter of 2 mm can be accurately targeted is 26%; lesions of 3 mm 61%; lesions of 4 mm 86%; lesions of 5 mm 96%; and lesions of 6 mm 99%. The likelihood of accurate sampling increases if more biopsy cores are used. MRI-TRUS fusion allows for accurate sampling of MRI-identified lesions with an OE of 2.33 mm. Lesions with a diameter of 3 mm or more can be accurately targeted. These results should be considered the lower limit of in vivo accuracy.

Dose comparison between pre and post operation of 125I seeds implantation guided by 3D print tamplate

To compare the dose difference between pre and post operation of (125)I seeds implantation guided by 3D print tamplate and investigate the dose accuracy. From August 2015 to November 2015, a total of 9 patients were selected and underwent 3D print tamplate guided (125)I seeds implantation in Hebei General Hospital. All patients had been fixed as the position of operation and then performed CT scan. After preplan was designed, the 3D tamplates were printed. The tumors were punctured through needles holes predesigned. Another CT scan was used to confirm the locations of needles and then seeds were implanted into tumor according to preplan. Postplan was performed after the operation. The D90, V90, V100, V150 and seeds number pre and post operation were collected and compared. The mean D90, V90, V100, V150 and seeds number preoperation was (7 684±3 279)cGy, 93.2%±0.8%, 89.8%±0.9%, 62.8%±4.7% and 58±17 respectively. The mean D90, V90, V100, V150 and seeds number postoperation was (7 531±3 523) cGy, 92.4%±2.0%, 88.0%±2.5%, 61.9%±5.3% and 56±17 respectively. The difference of all data between pre and post operation was not statistically significant (all P> 0.05). The dose parameters in postplan show no difference compared with preplan. For the fixed tumor, 3D print tamplate guided seeds implantation may become an easy repeated and standard procedure.

A Randomized Crossover Study Comparing a Novel Needle Guidance Technology for Simulated Internal Jugular Vein Cannulation

Background:Despite ultrasound guidance for central line placement, complications persist, as exact needle location is often difficult to confirm with standard two-dimension ultrasound. A novel real-time needle guidance technology has recently become available (eZono, Germany) that tracks the needle

US-guided Biopsy of Neck Lesions: The Head and Neck Neuroradiologist's Perspective.

Ultrasonographically (US) guided percutaneous biopsy of a neck lesion is a cost-effective, safe, and diagnostically effective procedure without radiation exposure. The benefit of real-time visualization of the needle location allows for instantaneous maneuvering of the needle trajectory for safe and accurate tissue sampling with short procedural time. Effective US-guided biopsy requires technical experience, strong clinical acumen, and skillful biopsy technique. A neuroradiologist's knowledge of head and neck anatomy and pathology allows correlation with cross-sectional imaging and enhances the understanding of US imaging evaluation. Familiarity with a spectrum of neck surgeries and reconstructions and expertise in imaging evaluation of the treated neck are invaluable in accurate identification of the target for biopsy in patients with treatment-related altered anatomy using US guidance. After thyroid nodules, the common adult neck masses are lymphadenopathy, head and neck cancer, salivary neoplasms, nerve sheath tumors, and inflammatory and infectious pseudomasses. Diagnostic expertise in the imaging characteristics of these individual pathologic conditions and their differential diagnoses also play an important role in choosing the biopsy technique and in procuring an adequate sample for diagnosis, including material for ancillary laboratory testing. Using an anatomic zone approach, this article illustrates the practical considerations in patient selection, the methodical analysis of preprocedure cross-sectional imaging and its correlation with real-time US evaluation, general principles for optimizing US instrumentation, and biopsy technique. In skillful hands, the versatility and portability of US make it the valuable modality for histologic sampling of superficial head and neck lesions. Online supplemental material is available for this article.

Factors Related to Radiation Exposure during Lumbar Spine Intervention.

Fluoroscopy guidance is useful to confirm anatomical landmark and needle location for spine intervention; however, it can lead to radiation exposure in patients, physicians, and medical staff. Physicians who used fluoroscopy should be cognizant of radiation exposure and intend to minimize radiation dose. We retrospectively reviewed three lumbar spine intervention procedures (nerve root block, medial branch block, and facet joint block) at our institution between June and December, 2014. We performed 268 procedures on 220 patients and found significant difference in radiation dose between two groups classified by performing physicians. The physician who controlled the fluoroscopy unit directly used significantly shorter fluoroscopy (6 seconds) that resulted in a smaller radiation dose (dose area product [DAP] 0.59 Gy∙cm2) than the physician supervising the radiographer controlling the fluoroscopy unit (72 seconds, DAP 5.31 Gy∙cm2, P < 0.001). The analysis indicates that the difference in fluoroscopy time depends on whether a physician or a radiographer controls the fluoroscopy unit.

A Randomized Crossover Study Comparing a Novel Needle Guidance Technology for Simulated Internal Jugular Vein Cannulation

Despite ultrasound guidance for central line placement, complications persist, as exact needle location is often difficult to confirm with standard two-dimension ultrasound. A novel real-time needle guidance technology has recently become available (eZono, Germany) that tracks the needle during insertion. This randomized, blinded, crossover study examined whether this needle guidance technology improved cannulation of a simulated internal jugular (IJ) vein in an ultrasound phantom. One hundred physicians were randomized to place a standard needle in an ultrasound neck phantom with or without the needle guidance system. Video cameras were placed externally and within the lumens of the vessels to record needle location in real time. The primary outcome measured was the rate of posterior wall puncture. Secondary outcomes included number of carotid artery punctures, number of needle passes, final needle position, time to cannulation, and comfort level with this new technology. The incidence of posterior vessel wall puncture without and with needle guidance was 49 and 13%, respectively (P < 0.001, odds ratio [OR] = 7.33 [3.44 to 15.61]). The rate of carotid artery puncture was higher without needle navigation technology than with needle navigation 21 versus 2%, respectively (P = 0.001, OR = 12.97 [2.89 to 58.18]). Final needle tip position being located within the lumen of the IJ was 97% accurate with the navigation technology and 76% accurate with standard ultrasound (P < 0.001, OR = 10.42 [2.76 to 40.0]). Average time for successful vessel cannulation was 1.37 times longer without guidance technology. This real-time needle guidance technology (eZono) shows significant improvement in needle accuracy and cannulation time during simulated IJ vein puncture.

Using rotation for steerable needle detection in 3D color-Doppler ultrasound images.

This paper demonstrates a new way to detect needles in 3D color-Doppler volumes of biological tissues. It uses rotation to generate vibrations of a needle using an existing robotic brachytherapy system. The results of our detection for color-Doppler and B-Mode ultrasound are compared to a needle location reference given by robot odometry and robot ultrasound calibration. Average errors between detection and reference are 5.8 mm on needle tip for B-Mode images and 2.17 mm for color-Doppler images. These results show that color-Doppler imaging leads to more robust needle detection in noisy environment with poor needle visibility or when needle interacts with other objects.

Fine Needle Aspiration in Thyroid Nodules - One Year Experience.

AIM:To estimate suspect nodule for benign or malignant characteristics, and to verify cytological features of the node with the fine needle aspiration (FNA) under ultrasound.DESIGN:A total of 106 patients were analyzed. FNA biopsy was performed at outpatient clinic via ultrasound. Inform consent was signed for each patient. Preparation of procedure with local anaesthesia was made by assistant nurse.PROCEDURE:Parallel approach of ultrasound guided fine needle aspiration (USGFNA) was used for each patient. This approach allows the operator to observe needle penetration, location and pathway of the entire needle within the neck, thyroid and nodule, which remain visible on the monitor. As a side effect commonly noticed mild pain and dizziness were recorded.RESULTS:General findings: According the gender, 96 (90.5%) of them were women and 10 (9.5%) men. Median age was 47 ± 9 years. Cytological findings: 5 patients were with papillary carcinoma, 3 with Hurtle cell metaplasia, 1 follicular tumour and 1 with unclear differentiation.CONCLUSION:Close collaboration between endocrinologists, morphologists and surgeons in a multidisciplinary frame is the key to correct preoperative thyroid cancer diagnosis and optimal treatment. FNA biopsy remains the most accurate diagnostic method in detecting thyroid cancer.

SU-E-T-301: Dosimetric Comparison Between Adaptive and Rectilinear Template-Based Prostate Seed Implants

Purpose: To compare the dosimetry of a standard rectilinear and an adaptive technique used in I125 prostate seed implants. Methods: To achieve favorable dosimetry in prostate implants we used adaptive needle updates to match actual positions in real-time. The seed locations were optimized based on actual needle locations. The seeds were delivered automatically with a robotic device seedSelectron™ (Elekta Brachytherapy). In this study, we evaluated the former approach against the standard rectilinear technique in which the needles have a parallel distribution. The treatment plans for 10 patients were analyzed. For comparison, the actual treatment plans were revised so each needle was repositioned to its original parallel location through the template. The analysis was performed by comparing the target coverage and dose to the organs at risk. The comparison was done using the following planning goals: the target D90> 90%, V100% > 90%, V50% <70% and V200% <30%; the urethra V125% < 1cm3 and V150%= 0cm3; and the Rectum V100%<1cm3 and V69% < 8cm3. The prescription dose to the target was 145Gy. Results: The average target volume and number of seeds were 44.39cm3(SD=11.14) and 74(SD=12), respectively. The D90 for adaptive and rectilinear plans was 159.9Gy(SD=2.99) and 155.53Gy(SD=4.04) resulting in a 2.74% difference for the average target coverage. A similar difference (1.75%) was noticed in the target V100[%]. No significant difference was noticed in the dose to the urethra and rectum. All planning goals were met with both the adaptive and rectilinear approach for each plan. Conclusion: The study reveals enhanced coverage of the target when using the adaptive needle adjustments as compared to the rectilinear approach for the analyzed cases. However, the differences in dosimetry did not translate to meaningful clinical outcomes.

Percutaneous transhepatic duodenostomy for a gastrectomy case with CT guidance and real-time visualization by an ultrasound and endoscopy

After gastrectomy, the remnant stomach, a small stomach behind the lateral segment of the liver, is thought to be a relative contraindication to receiving a percutaneous endoscopy-guided gastrostomy (PEG). We successfully performed a percutaneous duodenostomy in a case with remnant stomach. We used a transhepatic pull method with computed tomography (CT) guidance and real-time visualization by using ultrasound (US) and an endoscopy. The procedure was as follows: 1. Full stretching of the remnant stomach; 2. Insertion of a fine injection needle into the duodenal lumen through the lateral segment of the liver without an intrahepatic vascular and biliary injury using real-time visualization through US; 3. Confirmation of the location of the fine needle using abdominal CT, which showed the fine needle penetrating through the lateral segment and the duodenal lumen; 4. Insertion of the thick needle of the PEG kit just laterally of the fine needle; 5. Confirmation of the location of the thick needle using a repeated CT; 6. Endoscopic confirmation of the location of the two needles; 7. Changing the direction of the thick needle using guidance with endoscopy, inserting the thick needle into the duodenal lumen, and removing the fine needle; 8. Insertion of the guide wire through the thick needle; and 9. Placement of the PEG tube using the pull method. Using a real-time US scan, we detected the puncture of the anterior wall of the duodenum or stomach and avoided intrahepatic major vascular and biliary injuries.

Contralateral oblique view is superior to lateral view for interlaminar cervical and cervicothoracic epidural access.

The purpose of this study was to compare the reliability of the lateral fluoroscopic view and several contralateral oblique (CLO) views at different angles in visualizing and accurately predicting the position of the needle tip at the point of access in the posterior cervical and cervicothoracic epidural space. After the epidural space was accessed but before confirmation with contrast fluoroscopy, we prospectively obtained fluoroscopic images at eight different angles. Subsequent contrast injection confirmed epidural spread. Needle tip visualization and location of needle relative to bony landmarks were analyzed. The needle tip was clearly visualized in all CLO projections in all 24 subjects. CLO view at 50 degrees and at obliquity measured on magnetic resonance imaging (MRI) images provided the most consistent needle tip location. In these views, the epidural space was accessed at or just beyond the ventral laminar margin at the ventral interlaminar line or within the proximal half of the predefined CLO area in all patients. The needle tip was poorly visualized in the lateral view and the location of the needle tip was less well defined and independent of the needle location in the anteroposterior (AP) view. This study provides evidence that during cervical and cervicothoracic epidural access, the CLO view at 50 degrees and at MRI-measured obliquity is superior to the lateral view for the purpose of needle tip visualization and in providing a consistent landmark for accessing the epidural space. This article also introduces the concept of zones to describe needle position in the cervical and cervicothoracic spine in AP, lateral, and oblique views.

Effectiveness of Doppler Image of the Vertebral Artery as an Anatomical Landmark for Identification of Ultrasound-Guided Target Level in Cervical Spine.

Study DesignA prospective sonographic study.PurposeTo verify the effectiveness of simultaneous application of two landmarks, Doppler image of the vertebral artery and shape of the transverse tubercle of the seventh cervical (C7) vertebra.Overview of LiteratureCounting upwards from the C7 vertebra which only has a posterior tubercle of the transverse process is a commonly used method for ultrasound-guided cervical nerve root block. However, each transverse process has a different shape.MethodsSonograms of 20 volunteers were examined. At first, we identified the C7 transverse process based on the presence of the vertebral artery without the anterior tubercle. The C5 and C6 transverse processes were identified based on the presence of anterior tubercle without the vertebral artery. Subsequently, we placed needles on the C5, C6, and C7 transverse processes and the location and direction of needles were confirmed by fluoroscopy.ResultsIn the 120 segments, 93.3% of needles were placed correctly as desired; 97.5% of needles were placed on the 5C transverse process; 97.5% of needles were placed on the C6 transverse process; and 85.0% of needles were placed on the C7 transverse process, respectively. Both sides showed the same accuracy of 93.3%.ConclusionsSimultaneous application of Doppler image of the vertebral artery and shape of the C7 transverse tubercle showed 93.3% accuracy in identifying the target cervical level. Therefore, Doppler image of the vertebral artery can be considered to be a useful landmark for ultrasound-guided cervical nerve root block.

Ultrasound-guided lumbar plexus block using a transverse scan through the lumbar intertransverse space: a prospective case series.

A paramedian transverse scan (PMTS) can be used to delineate the anatomy relevant for ultrasound-guided lumbar plexus block (LPB) through the lumbar intertransverse space. This case series evaluated the feasibility of using the PMTS to guide LPBs for anesthesia. After research ethics committee approval and written informed consent, 15 American Society of Anesthesiologists physical status 1 to III patients with body mass index of less than 35 kg/m scheduled for lower-extremity surgery received an ultrasound-guided LPB and a sciatic nerve block for anesthesia. The blocks were performed using the PMTS and in-plane needle insertion. Localization of the lumbar plexus was confirmed by obtaining quadriceps muscle twitch. Successful blocks were defined as adequate anesthesia for lower-extremity surgery in the sensory territory of the lumbar plexus. The articular process and psoas muscle were visualized on ultrasound in all 15 patients (mean age, 46.3 ± 20.4 years; body mass index, 22.2 ± 2.4 kg/m), but the lumbar plexus was identified in two-thirds of the patients. Blocks were successfully performed in 14 (93%) of the 15 patients. Poor visibility in 1 patient (7%) precluded the use of ultrasound guidance. The needle was visualized in the psoas muscle in 14 patients (93%), whereas proper needle location was confirmed in all patients by nerve stimulation. Needle to lumbar plexus contact was delineated on ultrasound in 8 (53%) and 14 patients (93%), before and after injection of local anesthetic, respectively. Adequate anesthesia was accomplished in all patients within 30 minutes of injection. Ultrasound-guided LPBs can be reliably accomplished using the PMTS.