Posterior tibial nerve stimulation: is ultrasound guided needle placement more accurate?

INTRODUCTION To compare the accuracy of the transcutaneous ultrasound (US) in detecting the tibial nerve (TN) as opposed to digital palpation in the performance of posterior tibial nerve stimulation (PTNS). MATERIALS AND METHODS: After Institutional Review Board (IRB) approval, 25 adults were enrolled to quantify the difference in position of the distal TN by the use of US as opposed to cutaneous palpation. The position of the TN was determined first by the palpation method and then by using a L12-4MHz high frequency Linear Array Transducer. The difference in position between the two methods was determined in both proximal-distal (PD [Knee-Sole]) and anterior-posterior planes (AP). Statistical analysis was completed with numeric variables summarized with the sample median, range, and interquartile range (IQR). Categorical variables were summarized with the number and percentage of patients. Comparisons between AP and PD distances were performed using a nonparametric Wilcoxon signed rank test. Box and whisker plots were used to display individual observations graphically. All analyses and graphics were performed using SAS statistical software (version 9.4M5, SAS Institute Inc., Cary, NC, USA). RESULTS: Twenty-five patients were studied. The median AP distance between US and digital palpation was 2 mm (range, 0-5 mm; IQR, 2-3 mm). The median PD distance between US and digital palpation was 4 mm (range, 0-9 mm; IQR, 3-5 mm). The median difference between the AP and PD distances was 2 mm (range, -3-7 mm; IQR, 0-4 mm, p < 0.001). CONCLUSION: The use of US identifies the nerve with statistically significant greater accuracy than palpation technique along the PD plane.

Biceps Tendon Sheath Injection: An Anatomical Conundrum.

Objective: Long head biceps tendon peritendinous or sheath injections are routinely administered at or immediately distally to the bicipital groove. The main indication for injection remains the clinical diagnosis or treatment of biceps tendinopathy, although true inflammation of the tendon within the bicipital groove is rare. Because the tendon sheath is merely an extension of the joint cavity, it is plausible to assume that an injection into the sheath would result in intraarticular spread. Surprisingly, such an anatomical tenet has a vague confirmation in the published clinical literature. This experiment was undertaken to investigate patterns of injectate spread when peri-tendon injection at the bicipital groove is performed. Design: An experimental cadaveric study. Setting: An institutional clinical anatomy laboratory. Methods: Twelve ultrasound-guided methylene blue injections of the bicep tendon sheath were performed on cadaver specimens. Dissections and gross examination of staining of the internal joint surfaces were performed. Visual confirmation of the intra- and/or extra-articular spread of the injectate was performed. Results: In 11 specimens, injected contrast was found spreading onto the entire internal joint surface, including glenoid cartilage. One extraarticular injection was attributable to a technical issue. Conclusions: The experiment confirmed continuity of the joint capsule and the biceps tendon sheath. These results suggest a low diagnostic utility of peritendinous injections at the level of the bicep groove. Such injections would likely result in intraarticular deposit of the injectate. Nonetheless, this approach may be utilized as an alternative simplified access to the glenohumeral joint.

Sonographically guided costotransverse joint injections: a computed tomographically controlled cadaveric feasibility study.

OBJECTIVES: The primary purpose of this study was to describe and validate a novel sonographically guided costotransverse (CTRV) joint injection technique. METHODS: The bilateral T3-T10 CTRV joints of an unembalmed cadaveric specimen were localized using a 12-3-MHz linear array transducer. A 22-gauge, 2.5-in spinal needle was directed into the CTRV joint using an in-plane, lateral-to-medial approach under direct sonographic guidance. After needle placement, 3-dimensional computed tomographic (CT) images were obtained to assess the locations of the needle tips. This step was followed by injection of an iodinated contrast agent and repeated CT to assess the contrast flow pattern. An experienced musculoskeletal radiologist reviewed the CT images and assessed the accuracy of the injections (intra- or extra-articular). For intra-articular injections, a quantitative assessment of the percentage of injectate within the joint was performed. RESULTS: A total of 16 sonographically guided CTRV joint injections were completed on a single torso-pelvis specimen. Using our technique, 11 of 16 sonographically guided CTRV joint injections (68.8%) placed the contrast agent into the target joint. Quantitative analysis of the arthrograms showed 6 of 11 intra-articular injections (54.5%) with greater than 50% injectate within the joint capsule. CONCLUSIONS: To our knowledge, this study is the first to determine the feasibility of sonographically guided CTRV joint injections. Overall, 68.8% of injection attempts produced acceptable CTRV joint arthrograms, which compares favorably to a previously reported 76% accuracy rate for fluoroscopically guided CTRV joint injections. Although these injections are technically challenging, the use of sonographic guidance to perform CTRV joint injections is feasible and warrants further investigation to establish its role in the management of patients presenting with thoracic pain syndromes.

Utility of ultrasound-guided surface electrode placement in lateral femoral cutaneous nerve conduction studies.

INTRODUCTION: Meralgia paresthetica is a common clinical complaint for which some patients ultimately undergo surgical treatment. The lateral femoral cutaneous nerve (LFCN) has been difficult to reliably test electrophysiologically, likely due to anatomic variability and lack of responses in asymptomatic obese subjects. METHODS: We compared a novel ultrasound-guided antidromic sensory nerve conduction study (NCS) with a technique described previously in a population of normal subjects, of whom 50% had body mass indices within the obese range (>27.5). RESULTS: Responses were obtained in at least 92% of subjects using either technique, and 92% of normal subjects had <60% interside variability using the ultrasound-guided technique. CONCLUSIONS: LFCN sensory nerve action potentials can be obtained in the vast majority of normal subjects, even in an obese population and can provide a useful sensory NCS for evaluation of mid-lumbar radiculopathy, plexopathy, or meralgia paresthetica.

Ultrasound-guided thoracic facet injections: description of a technique.

OBJECTIVES: The purpose of this study was to describe a technique using ultrasound guidance to perform thoracic facet joint injections. METHODS: A single examiner used ultrasound to localize paired thoracic facet joints from T1-2 through T10-11 on a fresh frozen cadaveric specimen. This was done using a 2- to 5-MHz curvilinear transducer over the target facet in the sagittal plain with the cadaver in the prone position. Target facets were identified using the most inferior rib as a starting point and scanning medially toward its axial attachment and further medially and slightly superior over the most caudal thoracic facet (T11-12). Subsequent ipsilateral facet joints were identified by simply moving the transducer superiorly in the sagittal plain until the next cephalad facet was encountered. After identification, injections were performed using a long-axis or "in-line" approach with continual visualization of the needle into each facet joint. After needle placement, computed images were obtained from a fluoroscopy machine capable of 3-dimensional reconstruction to assess the location of the needle tips. After this, 0.5 mL of an iodinated contrast agent was injected, and another 3-dimensional reconstruction was performed to assess the location of the injected agent. A senior radiology resident reviewed the computed images in coronal, axial, and sagittal planes. Accuracy was determined in terms of contrast location, graded as either intra-articular or extra-articular. RESULTS: Sixteen (80%) of 20 injections performed showed intra-articular contrast spread. CONCLUSIONS: We describe a relatively feasible technique for performing thoracic facet joint injections using ultrasound guidance. Further verification of this technique, and modification if applicable, should be performed before directly applying this technique in a clinical practice setting.

Proximal Rectus Femoris Avulsion: Ultrasonic Diagnosis and Nonoperative Management.

OBJECTIVE: To present a case of ultrasonic diagnosis and nonoperative management of a complete proximal rectus femoris avulsion in a National Collegiate Athletic Association Division 1 soccer goalkeeper. BACKGROUND: While delivering a goal kick, a previously uninjured 24-year-old collegiate soccer goalkeeper had the sudden onset of right anterior thigh pain. He underwent rehabilitation with rapid resolution of his presenting pain but frequent intermittent recurrence of anterior thigh pain. After he was provided a definitive diagnosis with musculoskeletal ultrasound, he underwent an extended period of rehabilitation and eventually experienced complete recovery without recurrence. DIFFERENTIAL DIAGNOSIS: Rectus femoris avulsion, rectus femoris strain or partial tear, inguinal hernia, or acetabular labral tear. TREATMENT: Operative and nonoperative options were discussed. In view of the player's recovery, nonoperative options were pursued with a good result. UNIQUENESS: Complete proximal rectus femoris avulsions are rare. Our case contributes to the debate on whether elite-level kicking and running athletes can return to full on-field performance without surgery. CONCLUSIONS: Complete proximal rectus femoris avulsions can be treated effectively using nonoperative measures with good preservation of function even in the elite-level athlete. In addition, musculoskeletal ultrasound is an excellent tool for on-site evaluation and may help guide prognosis and management.

Ultrasound-guided blockade of the lateral femoral cutaneous nerve: technical description and review of 10 cases.

Blockade of the lateral femoral cutaneous nerve (LFCN) is performed for therapeutic management of meralgia paresthetica and as a regional anesthetic technique. The conventional technique is associated with high failure rates secondary to variable LFCN anatomy. We describe a technique for blockade of the LFCN using ultrasound guidance. A cross-sectional view of the LFCN was obtained by identifying the anterior superior iliac spine, then moving a 14-to-7MHz linear array ultrasound probe in a medial caudal direction until the nerve was encountered. The needle was advanced to the LFCN under ultrasound guidance via a lateral to medial approach. Injection using dynamic ultrasound demonstrated excellent perineural spread. Ten subjects underwent successful blockade of the LFCN with this technique. Five subjects were obese. Use of ultrasound for precise needle placement allowed low injection volumes to be utilized. Theref were no complications. Ultrasound guidance can facilitate blockade of the LFCN for diagnostic and therapeutic purposes and may be particularly beneficial with patients with challenging surface anatomic landmarks, or when low volume injections are desired.