Bernhard Moriggl

Ultrasound-guided lumbar facet nerve block: accuracy of a new technique confirmed by computed tomography.

Background:Lumbar facet nerve (medial branch) blocks are often used to diagnose facet joint-mediated pain. The authors recently described a new ultrasound-guided methodology. The current study determines its accuracy using computed tomography scan controls. Methods:Fifty bilateral ultrasound-guided approaches to the lumbar facet nerves were performed in five embalmed cadavers. The target point was the groove at the cephalad margin of the transverse (or costal) process L1–L5 (medial branch T12–L4) adjacent to the superior articular process. Axial transverse computed tomography scans, with and without 1 ml contrast dye, followed to evaluate needle positions and spread of contrast medium. Results:Forty-five of 50 needle tips were located at the exact target point. The remaining 5 were within 5 mm of the target. In 47 of 50 cases, the applied contrast dye reached the groove where the nerve is located, corresponding to a simulated block success rate of 94% (95% confidence interval, 84–98%). Seven of 50 cases showed paraforaminal spread, 5 of 50 showed epidural spread, and 2 of 50 showed intravascular spread. Despite the aberrant distribution, all of these approaches were successful, as indicated by contrast dye at the target point. Abnormal contrast spread was equally distributed among all lumbar levels. Contrast traces along the needle channels were frequently observed. Conclusions:The computed tomography scans confirm that our ultrasound technique for lumbar facet nerve block is highly accurate for the target at all five lumbar transverse processes (medial branches T12–L4). Aberrant contrast medium spread is comparable to that of the classic fluoroscopy-guided method.

Cervical and High Thoracic Ligamentum Flavum Frequently Fails to Fuse in the Midline

Background Cervical and high thoracic epidural anesthesia and analgesia have gained increasing importance in the treatment of painful conditions and as components of anesthetics for cardiac and breast surgery. In contrast to the hanging-drop technique, the loss-of-resistance technique is thought to rely on the penetration of the ligamentum flavum. However, the exact morphology of the ligamentum flavum at different vertebral levels remains controversial. Therefore, the aim of this study was to investigate the incidence and morphology of cervical and high thoracic ligamentum flavum mid-line gaps in embalmed cadavers. Methods Vertebral column specimens were obtained from 52 human cadavers. On each dissected level, ligamentum flavum mid-line gaps were recorded and evaluated with respect to shape and size. Results The following variations were encountered: complete fusion in the mid-line, mid-line fusion with a gap in the caudal part, mid-line gap, and mid-line gap with widened caudal end. The incidence of mid-line gaps at the following levels was: C3–C4: 66%, C4–C5: 58%, C5–C6: 74%, C6–C7: 64%, C7–T1: 51%, Th1–Th2: 21%, Th2–Th3: 11%, Th3–Th4: 4%, Th4–Th5: 2%, and Th5–Th6: 2%. The mean width of mid-line gaps was 1.0 ± 0.3 mm. Conclusions In conclusion, the present study shows that gaps in the ligamenta flava are frequent at cervical and high thoracic levels but become rare at the T3/T4 level and below, such that one cannot always rely on the ligamentum flavum as a perceptible barrier to epidural needle placement at these levels.

Ultrasound-guided paravertebral puncture and placement of catheters in human cadavers: an imaging study

BACKGROUND During paravertebral block, the anterolateral limit of the paravertebral space, which consists of the pleura, should preferably not be perforated. Also it is possible that, during the block, the constant superior costotransverse ligament can be missed in the loss-of-resistance technique. We therefore aimed to develop a new technique for an ultrasound-guided puncture of the paravertebral space. METHODS We performed 20 punctures and catheter placements in 10 human cadavers. A sonographic view showing the pleura and the superior costotransverse ligament was obtained with a slightly oblique scan using a curved array transducer. After inline approach, injection of 10 ml normal saline confirmed the correct position of the needle tip, distended the space, and enabled catheter insertion. The spread of contrast dye injected through the catheters was assessed by CT scans. RESULTS The superior costotransverse ligament and the paravertebral space were easy to identify. The needle tip reached the paravertebral space without problems under visualization. In contrast, the introduction of the catheter was difficult. The CT scan revealed a correct paravertebral spread of contrast in 11 cases. Out of the remaining, one catheter was found in the pleural space, in six cases there was an epidural, and in two cases there was a prevertebral spread of contrast dye. CONCLUSIONS We successfully developed a technique for an accurate ultrasound-guided puncture of the paravertebral space. We also showed that when a catheter is introduced through the needle with the tip lying in the paravertebral space, there is a high probability of catheter misplacement into the epidural, mediastinal, or pleural spaces.

A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block.

IMPLICATIONS We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.

Feasibility of ultrasound-guided sacroiliac joint injection considering sonoanatomic landmarks at two different levels in cadavers and patients.

OBJECTIVE Sacroiliitis is often caused by rheumatic diseases, and besides other therapeutic options, treatment consists of intraarticular injection of corticosteroids. The purpose of this study was to assess the feasibility of ultrasound (US)-guided sacroiliac joint (SI joint) injection at 2 different puncture levels in cadavers and patients when defined sonoanatomic landmarks were considered. METHODS After defining sonoanatomic landmarks, US-guided needle insertion was performed in 10 human cadavers (20 SI joints) at 2 different puncture sites. Upper level was defined at the level of the posterior sacral foramen 1 and lower level at the level of the posterior sacral foramen 2. In 10 patients with unilateral sacroiliitis, injection at the most feasible level was attempted. RESULTS Computed tomography confirmed correct intraarticular needle placement in cadavers by showing the tip of the needle in the joint and intraarticular diffusion of contrast media in 16 (80%) of 20 SI joints (upper level 7 [70%] of 10; lower level 9 [90%] of 10). In all 4 cases in which needle insertion failed, intraarticular SI joint injection at the other level was successful. In patients, 100% of US-guided injections were successful (8 lower level, 2 upper level), with a mean pain relief of 8.6 after 3 months. CONCLUSION US guidance of needle insertion into SI joints was feasible at both levels when defined sonoanatomic landmarks were used. If SI joint alterations do not allow for direct visualization of the dorsal joint space of the lower level, which is easier to access, the upper level might offer an appropriate alternative.

Internal mammary vessels: anatomical and clinical considerations

This study was designed to investigate the anatomy of the internal mammary (thoracic) artery (IMA) and comitant vein(s) (IMV) relevant to their use in microsurgery. We dissected the internal mammary (thoracic) vessels bilaterally in 86 cadavers from the clavicle down to the 6th rib. At the level of the 4th rib, the distance between the sternum and the IMA was large enough [range 10.0-23.6 mm] and the diameter of the IMA [range 0.99-2.55 mm] and comitant vein(s) [range 0.64-4.45 mm] wide enough for both end-to-end and/or end-to-side anastomosis. These results were in close agreement with supplementary measurements obtained by Doppler ultrasound in 34 healthy female volunteers. Based on all these findings we suggest that the internal mammary vessels are suitable recipient vessels for free tissue transfers in the thoracic region, especially for breast reconstruction with the free transverse rectus abdominis myocutaneous (TRAM) flap.

Achilles Tendon Assessed with Sonoelastography: Histologic Agreement

PURPOSE To compare and determine the level of agreement of findings at conventional B-mode ultrasonography (US) and sonoelastography of the Achilles tendon with findings at histologic assessment. MATERIALS AND METHODS This study was conducted with the approval of the institutional review boards, and all cadavers were in legal custody of the study institution. Thirteen Achilles tendons in 10 cadavers (four male, six female; age range, 70-90 years) were examined with B-mode US and sonoelastography. B-mode US grading was as follows: Grade 1 indicated a normal-appearing tendon with homogeneous fibrillar echotexture; grade 2, a focal fusiform or diffuse enlarged tendon; and grade 3, a hypoechoic area with or without tendon enlargement. Sonoelastography grading was as follows: Grade 1 indicated blue (hardest) to green (hard); grade 2, yellow (soft); and grade 3, red (softest). Twenty-five biopsy specimens from representative lesions of the middle and distal thirds of the Achilles tendons were evaluated histologically. The concordance of B-mode US grading compared with sonoelastographic grading was assessed by using κ analysis. RESULTS With B-mode US and sonoelastography, all 11 tendon thirds of histologically normal tendons were verified as normal (grade 1). Sonoelastography depicted 14 of 14 (100%) tendon thirds with histologic degeneration (grade 2 or 3), whereas B-mode US could depict only 12 of 14 (86%) lesions (grade 2 or 3). Only moderate agreement between B-mode US and sonoelastography was seen (κ = 0.52, P < .001). CONCLUSION Sonoelastography might help predict signs of histopathologic degeneration of Achilles tendinosis, potentially more sensitively than B-mode US.

Sonographic visualization and ultrasound-guided blockade of the greater occipital nerve: a comparison of two selective techniques confirmed by anatomical dissection.

BACKGROUND Local anaesthetic blocks of the greater occipital nerve (GON) are frequently performed in different types of headache, but no selective approaches exist. Our cadaver study compares the sonographic visibility of the nerve and the accuracy and specificity of ultrasound-guided injections at two different sites. METHODS After sonographic measurements in 10 embalmed cadavers, 20 ultrasound-guided injections of the GON were performed with 0.1 ml of dye at the classical site (superior nuchal line) followed by 20 at a newly described site more proximal (C2, superficial to the obliquus capitis inferior muscle). The spread of dye and coloration of nerve were evaluated by dissection. RESULTS The median sonographic diameter of the GON was 4.2 x 1.4 mm at the classical and 4.0 x 1.8 mm at the new site. The nerves were found at a median depth of 8 and 17.5 mm, respectively. In 16 of 20 in the classical approach and 20 of 20 in the new approach, the nerve was successfully coloured with the dye. This corresponds to a block success rate of 80% (95% confidence interval: 58-93%) vs 100% (95% confidence interval: 86-100%), which is statistically significant (McNemars test, P=0.002). CONCLUSIONS Our findings confirm that the GON can be visualized using ultrasound both at the level of the superior nuchal line and C2. This newly described approach superficial to the obliquus capitis inferior muscle has a higher success rate and should allow a more precise blockade of the nerve.

Lumbar plexus in children. A sonographic study and its relevance to pediatric regional anesthesia.

Background:Pediatric regional anesthesia has gained increasing interest over the past decades. The current study was conducted to investigate the lumbar paravertebral region and the lumbar plexus at L3–L4 and L4–L5 by means of sonography to obtain fundamentals for the performance of ultrasound-guided posterior lumbar plexus blocks. Methods:Thirty-two children (12 boys, 20 girls) with American Society of Anesthesiologists physical status I or II were enrolled in the current study. The lumbar paravertebral region was visualized at L3–L4 and L4–L5 on two corresponding posterior sonograms (longitudinal, transverse). The lumbar plexus had to be delineated, and skin-plexus distances were measured. In a series of five pediatric patients undergoing inguinal herniotomy, ultrasound-guided posterior lumbar plexus blocks at L4–L5 were performed. Results:The children were stratified into three age groups (group 1: > 3 yr and ≤ 5 yr; group 2: > 5 yr and ≤ 8 yr; group 3: > 8 yr and ≤ 12 yr). The lumbar plexus could be delineated at L3–L4 and L4–L5 in 19 of 20 cases in group 1, in 17 of 20 cases in group 2, in 22 of 24 cases at L3–L4 in group 3, and in 16 of 24 cases at L4–L5 in group 3. In all patients, the lumbar plexus was situated within the posterior part of the psoas major muscle. Skin-plexus distances showed statistical significant differences between groups 1 and 3 and between groups 2 and 3. The strongest positive correlation existed between skin-plexus distances and the children’s weight. Ultrasound guidance enabled safe und successful posterior approaches to the lumbar plexus, thus resulting in effective anesthesia and analgesia of the inguinal region. Conclusions:Sonography of the lumbar plexus in children proved to be feasible. Skin-plexus distances correlated with the children’s weight rather than with their age. The sonographic findings were fundamental for the performance of successful ultrasound-guided posterior approaches in a small group of pediatric patients.

Ultrasound-guided suprascapular nerve block, description of a novel supraclavicular approach

Background and Objectives The suprascapular nerve (SSN) block is frequently performed for different shoulder pain conditions and for perioperative and postoperative pain control after shoulder surgery. Blind and image-guided techniques have been described, all of which target the nerve within the supraspinous fossa or at the suprascapular notch. This classic target point is not always ideal when ultrasound (US) is used because it is located deep under the muscles, and hence the nerve is not always visible. Blocking the nerve in the supraclavicular region, where it passes underneath the omohyoid muscle, could be an attractive alternative. Methods In the first step, 60 volunteers were scanned with US, both in the supraclavicular and the classic target area. The visibility of the SSN in both regions was compared. In the second step, 20 needles were placed into or immediately next to the SSN in the supraclavicular region of 10 cadavers. The accuracy of needle placement was determined by injection of dye and following dissection. Results In the supraclavicular region of volunteers, the nerve was identified in 81% of examinations (95% confidence interval [CI], 74%–88%) and located at a median depth of 8 mm (interquartile range, 6–9 mm). Near the suprascapular notch (supraspinous fossa), the nerve was unambiguously identified in 36% of examinations (95% CI, 28%–44%) (P < 0.001) and located at a median depth of 35 mm (interquartile range, 31–38 mm; P < 0.001). In the cadaver investigation, the rate of correct needle placement of the supraclavicular approach was 95% (95% CI, 86%–100%). Conclusions Visualization of the SSN with US is better in the supraclavicular region as compared with the supraspinous fossa. The anatomic dissections confirmed that our novel supraclavicular SSN block technique is accurate.