Imaging of Anatomical Variants of the Lower Limb Nerves: Clinical and Preoperative Relevance.

Anatomical variants of peripheral nerves of the lower limb are relatively frequent and vulnerable to injury if not considered by the surgeon. Surgical procedures or percutaneous injections are often performed without knowing the anatomical situation. In a patient with normal anatomy, these procedures are mostly performed smoothly without major nerve complications. But in the case of anatomical variants, surgery may be challenging as "new" anatomical prerequisites complicate the procedure. In this context, high-resolution ultrasonography as the first-line imaging modality to depict peripheral nerves, has become a helpful adjunct in the preoperative setting. It is crucial, on the one hand, to gain knowledge of anatomical nerve variants and, on the other hand, to depict the anatomical situation preoperatively, to minimize the risk of surgical trauma to a nerve and make surgeries safer.

Ultrasound-guided injection into the lateral crico-arytenoid muscle: a pilot study.

OBJECTIVES: The anterior, percutaneous Botulinum neurotoxin (BoNT) injection in the lateral cricoarytenoid muscle (LCA) guided by laryngeal electromyography (LEMG) is considered the golden standard treatment for several neurolaryngological disorders. The study presented in this article aims to assess the effectiveness of an alternative approach by which the injection is performed laterally under ultrasound monitoring. STUDY DESIGN: Anatomical dissection study in human cadavers. SETTINGS: Academic health care center. METHODS: Ultrasound-guided bilateral dye (0.1 mL of dye solution containing cold-curing polymers, latex, acrylates, acrylic esters, alcohol, and green color) injection in the LCA was performed by means of 24G needles and 1 mL syringes using the lateral approach. The dye location and distribution were assessed by anatomic dissection, performed immediately after the injection. RESULTS: In 9/10 specimens, the dye was exclusively detectable in the LCA. In 1/10 case (left side), the dye could not be delivered in the LCA because of unintended penetration of the thyroid cartilage by the needle during injection. Anatomic dissection confirmed that the dye spread neither into the thyroarytenoid (TA) nor the cricothyroid muscle (CT). CONCLUSIONS: The anatomic dissection following lateral dye injection in the LCA under ultrasound guide confirmed the precision of this approach in delivery a substance exclusively in a pre-determined target. This feature makes this method an interesting addition or alternative to the standard LEMG-guided BoNT injection at least when the LCA is its target. LEVEL OF EVIDENCE: III.

Contemporary surgical management of skull base chordomas-Anatomical reflections on a single center experience retrospective case series.

Chordoma, a rare, locally aggressive tumor can affect the central skull base, usually centered at the midline. Complete surgical resection remains mainstay of therapy in case of primary as well as recurrent tumors. Owing to their secluded location, surgical resection of skull base chordomas remains a challenge, even though the recent advancement of endoscopic endonasal approaches has had a significant positive impact on the management of these patients. Endoscopic endonasal approaches have been shown to significantly reduce surgical morbidity when compared to traditional open approaches; however, the classical endoscopic transclival midline approach fails to sufficiently expose parts of many skull base chordomas. More recent refinements of the technique, such as the interdural pituitary transposition and posterior clinoidectomy, the transpterygoid plate approach and the transcondylar far medial approach enable the surgeon the increase the resection rate in these patients. This retrospective case series focuses on anatomical aspects in the surgical management of patients with skull base chordomas. We outline the surgical anatomy of contemporary endoscopic approaches to the skull base based intraoperative illustrations as well as pre- and postoperative 3D reconstructed CT and MR images if our patients. This article should help the clinical choose the most appropriate approach and be aware of relevant anatomy as well as potential shortcomings of a given approach.

Anatomic basis for a new ultrasound-guided, mini-invasive technique for release of the deep transverse metatarsal ligament.

INTRODUCTION: Morton's neuroma is an entrapment neuropathy of the third common plantar digital nerve, caused by the deep transverse metatarsal ligament (DTML). Minimally invasive or percutaneous surgery is a very common procedure, but surgical effectivity of this technique remains controversial. The goal of our study was to prove the effectiveness and safety of a new ultrasound-guided technique for DTML-release in a cadaver model. MATERIALS, METHODS, AND RESULTS: The DTML was visualized in 10 fresh frozen donated body to science-feet (eight male and two females, five left and five right) using an US device (GE Logic R7; 13 MHz linear probe, Madrid, Spain). Consecutively, minimally invasive ultrasound-guided surgery was performed. Exclusion criteria of the donated bodies to science were previous history of forefoot surgery and space occupying mass lesions. The complete release of the ligament was achieved in all specimens without damage of any important anatomical structures as proven by anatomical dissection. CONCLUSIONS: The results of this study indicate that our novel approach of an ultrasound-guided release of the DTML is safer and more effective compared to blind techniques. The DTML could reliably be visualized and securely cut through a dorsal, minimally invasive surgical incision of only 2 mm.

Anatomical basis of a safe mini-invasive technique for lengthening of the anterior gastrocnemius aponeurosis.

BACKGROUND: The surgical procedure itself of lengthening the gastrocnemius muscle aponeurosis is performed to treat multiple musculoskeletal, neurological and metabolical pathologies related to a gastro-soleus unit contracture such as plantar fasciitis, Achilles tendinopathy, metatarsalgia, cerebral palsy, or diabetic foot ulcerations. Therefore, the aim of our research was to prove the effectiveness and safety of a new ultrasound-guided surgery-technique for the lengthening of the anterior gastrocnemius muscle aponeurosis, the "GIAR"- technique: the gastrocnemius-intramuscular aponeurosis release. METHODS AND RESULTS: An ultrasound-guided surgical GIAR on ten fresh-frozen specimens (10 donors, 8 male, 2 females, 5 left and 5 right) was performed. Exclusion criteria of the donated bodies to science were BMI above 35 (impaired ultrasound echogenicity), signs of traumas in the ankle and crural region, a history of ankle or foot ischemic vascular disorder, surgery or space-occupying mass lesions. The surgical procedures were performed by two podiatric surgeons with more than 6 years of experience in ultrasound-guided procedures. The anterior gastrocnemius muscle aponeurosis was entirely transected in 10 over 10 specimens, with a mean portal length of 2 mm (± 1 mm). The mean gain at the ankle joint ROM after the GIAR was 7.9° (± 1.1°). No damages of important anatomical structures could be found. CONCLUSION: Results of this study indicate that our novel ultrasound-guided surgery for the lengthening of the anterior gastrocnemius muscle aponeurosis (GIAR) might be an effective and safe procedure.

Are single-injection erector spinae plane block and multiple-injection costotransverse block equivalent to thoracic paravertebral block?

BACKGROUND: Thoracic paravertebral block (TPVB) is considered the gold standard for hemithoracic regional anaesthesia. Erector spinae plane block (ESPB) is a new posterior thoracic wall block. Multiple-injection costotransverse block (MICB) mimics TPVB but with injection points within the thoracic intertransverse tissue complex and posterior to the superior costotransverse ligament. We aimed to compare the spread of injectate into the thoracic paravertebral space (TPVS) resulting from single-injection ESPB and MICB, respectively, with TPVB. METHODS: Ten soft-embalmed cadavers were utilised. In five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided single-injection ESPB or single-injection TPVB; vice versa on the other side. In another five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided MICB or multiple-injection TPVB. About 20 mL of dye was injected in each hemithorax with all techniques. RESULTS: With TPVB, the dye was consistently present in the TPVS with concomitant epidural spread in the majority of cases. The injectate spread into the TPVS with ESPB (60%) and MICB (100%). MICB consistently stained the ventral rami (T1-7), communicating rami and thoracic sympathetic trunk without epidural spread. Dissection after MICB revealed dye spread into the TPVS via the costotransverse foramina and along the dorsal branches of the posterior intercostal veins. CONCLUSIONS: Consistent spread of dye into the TPVS colouring the ventral rami, the communicating rami, and the sympathetic trunk was observed with MICB; in this respect equivalent to TPVB. ESPB exhibited only partial success and was not equivalent to TPVB. No epidural spread was found with neither MICB nor ESPB.

Cutaneous anaesthesia of hip surgery incisions with iliohypogastric and subcostal nerve blockade: A randomised trial.

BACKGROUND: Cutaneous nerve blockade may improve analgesia after hip surgery. Anaesthesia after the lateral femoral cutaneous (LFC) nerve block is too distal for complete coverage of most hip surgery incisions, which requires additional anaesthesia of the adjacent, proximal area. The transversalis fascia plane (TFP) block potentially anaesthetises the iliohypogastric and subcostal nerves. The primary aim of the present study was to investigate, if the TFP block provides cutaneous anaesthesia adjacent to the LFC nerve block. METHODS: Active vs placebo TFP blocks were compared in a paired randomised controlled trial (RCT) in 20 volunteers, who all had bilateral LFC nerve blocks. The day preceding the RCT, the area anaesthetised by a novel selective ultrasound guided subcostal nerve block was identified bilaterally in order to assess the contribution of the subcostal nerve to the area anaesthesia by the TFP block. RESULTS: Anaesthesia of the lateral hip region after TFP block was 80%. The cutaneous anaesthesia after active TFP block was in continuity with the LFC nerve block in 65%. Combined TFP and LFC nerve blockade significantly increased the coverage of hip surgery incisions compared to LFC nerve block alone. The success rate of blocking the subcostal nerve was 50% with the TFP block. CONCLUSION: The TFP block anaesthetises the skin proximal to the LFC nerve block by anaesthetising the iliohypogastric and subcostal nerves. TFP block as a supplement to LFC nerve block improves the coverage of the proximal surgical incisions used for hip surgery.

The Subtemporal Approach to the Lateral Midbrain with and without Zygomatic Osteotomy: An Anatomical Study.

The subtemporal approach provides a narrow operative corridor to the crus cerebrum and adjacent structures of the crural, interpeduncular, and ambient cistern. Addition of a zygomatic osteotomy widens this narrow corridor and spares retraction of the temporal lobe. We investigate and compare the morphometric parameters of the subtemporal approach with versus without zygomatic osteotomy. On each side of four cadaveric heads, a temporal craniotomy was performed to gain access to the crus cerebrum and adjacent subarachnoid cisterns using a subtemporal approach. Operative corridor width and corridor working angle were measured with and without brain retraction on each specimen side. Next, a zygomatic osteotomy was performed followed by full downward reflection of the temporalis muscle and further drilling of the squamous part of the temporal bone. Lastly, operative corridor width and corridor working angle were measured again for comparison. The subtemporal operating corridor was (mean/SD): 5.8/2.6 mm without retraction, 11.4/4.3 mm with retraction, and 13.5/6.5° working angle. After addition of a zygomatic osteotomy, the operative corridor was 8/9.2/4.3 mm without retraction, 14.7/4.5 mm with retraction, 31.8/3.1° working angle. Zygomatic osteotomy significantly increased the operative corridor working angle of the subtemporal approach. Furthermore, we demonstrate a direct approach into the interpeduncular fossa. Clin. Anat. 32:710-714, 2019. © 2019 Wiley Periodicals, Inc.

Clinical-anatomic mapping of the tarsal tunnel with regard to Baxter's neuropathy in recalcitrant heel pain syndrome: part I.

PURPOSE: Neuropathy of the Baxter nerve (BN) seems to be the first cause of the heel pain syndrome (HPS) of neurological origin. METHODS: 41 alcohol-glycerol embalmed feet were dissected. We documented the pattern of the branches of the tibial nerve (TN) and describe all relevant osteofibrous structures. Measurements for the TN branches were related to the Dellon-McKinnon malleolar-calcaneal line also called DM line (DML) for the proximal TT and the Heimkes Triangle for the distal TT. Additionally, we performed an ultrasound-guided injection procedure of the BN and provide an algorithm for clinical usage. RESULTS: The division of the TN was 16.4 mm proximal to the DML. The BN branches off 20 mm above the DML center or 30 mm distally to it. In most of the cases, the medial calcaneal branch (MCB) originated from the TN proximal to the bifurcation. Possible entrapment spots for the medial and lateral plantar nerve (MPN, LPN), the BN and the MCB are found within a circle of 5 mm radius with a probability of 80%, 83%, and 84%, respectively. In ten out of ten feet, the US-guided injection was precisely allocated around the BN. CONCLUSIONS: Our detailed mapping of the TN branches and their osteofibrous tubes at the TT might be of importance for foot and ankle surgeons during minimally invasive procedures in HPS such as ultrasound-guided ankle and foot decompression surgery (UGAFDS).

High-resolution ultrasonography of the normal extratemporal facial nerve.

The technical advances in sonography of the past decade have supported the rapid improvement of high-resolution imaging, which enables the quick visualization of peripheral nerves at relatively limited costs. Recently, the possibility of visualizing the extratemporal facial nerve (FN) has been considered. This manuscript describes the first systematic evaluation in cadavers, of a novel ultrasonographic approach with this specific aim. Eight cadaveric hemifaces were evaluated by means of high-frequency ultrasound with two linear (13 and 22 MHz) and a convex transducer (6.6 MHz), to detect the extratemporal course of the FN starting from its exit at the stylomastoid foramen: the main trunk, the parotid plexus between the two parts of the parotid gland, the distal branches terminating into the orbicularis oculi and the zygomatic major muscle. Ultrasound-guided color injections and FN dissection were performed to confirm the results. The main trunk of the FN, as it exits the stylomastoid foramen, was correctly stained in 6/8 cases, the parotid plexus in 8/8 cases. The branches innervating the orbicularis oculi muscle were stained in 7/7 and the branches innervating the zygomatic major muscle in 6/7 hemifaces, after 1 was withdrawn due to insufficient image quality. Through our novel approach of high-resolution ultrasonography we could identify the various portions of the extratemporal FN, including its main trunk leaving the stylomastoid foramen, in an accurate and reproducible way. Further in vivo animal and clinical studies have been planned to confirm these initial results from cadavers.

Sonoelastography of the Common Flexor Tendon of the Elbow with Histologic Agreement: A Cadaveric Study.

Purpose To determine the correlation of the results of conventional B-mode ultrasonography (US) and compression sonoelastography with histologic results in common flexor tendons of the elbow in human cadavers. Materials and Methods Twenty-five common flexor tendons were evaluated in 16 fresh, unembalmed cadavers of 11 women with a median age of 85 years (range, 71-101 years) and five men with a median age of 78 years (range, 70-88 years). Informed consent was provided according to the last will of the donors. B-mode US results were classified as grade 1, normal tendon with homogeneous fibrillar pattern; grade 2, tendon thickening or hypoechoic areas and/or calcifications in less than 30% of the tendon; or grade 3, hypoechoic areas and/or calcifications greater than 30% of the tendon. Sonoelastographic results were grade 1, blue (hardest) to green (hard); grade 2, yellow (soft); and grade 3, red (softest). The intraclass correlation coefficient was calculated to determine agreement with histologic findings for each B-mode US, sonoelastographic, and combined B-mode US and sonoelastographic examination. Histologic results were grade 1, normal, with parallel fibrillar pattern; grade 2, mild tendinopathy, with cellular infiltration, angiogenesis, or fatty vacuoles; or grade 3, severe tendinopathy, with loss of parallel collagen structure and necrosis. Results Histologic alterations were detected in 44% (11 of 25) of biopsy specimens. Intraclass correlation with histologic results was 0.57 for B-mode US, 0.68 for sonoelastography, and 0.84 for the combination of the two approaches. Conclusion The addition of sonoelastography to B-mode US provided statistically significant improvement in correlation with histologic results compared with the use of B-mode US alone (P < .02). © RSNA, 2016 Online supplemental material is available for this article.

Extensor tendinopathy of the elbow assessed with sonoelastography: histologic correlation.

PURPOSE: To compare agreement between conventional B-mode ultrasound (US) and compression sonoelastography (SEL) of the common extensor tendons of the elbow with histological evaluation. MATERIALS AND METHODS: Twenty-six common extensor tendons were evaluated in 17 cadavers (11 females, median age 85 years and 6 males, median age 80 years). B-mode US was graded into: Grade 1, homogeneous fibrillar pattern; grade 2, hypoechoic areas and/or calcifications <30%; and grade 3 > 30%. SEL was graded into: Grade 1 indicated blue (hardest) to green (hard); grade 2 yellow (soft); and grade 3 red (softest). B-mode US, SEL, and a combined grading score incorporating both were compared to histological findings in 76 biopsies. RESULTS: Histological alterations were detected in 55/76 biopsies. Both modalities showed similar results (sensitivity, specificity, and accuracy 84%, 81%, and 83% for B-mode US versus 85%, 86%, and 86% for SEL, respectively, P > 0.3). However, a combination of both resulted in significant improvement in sensitivity (96%, P < 0.02) without significant change in specificity (81%, P < 0.3), yielding an improved overall accuracy (92%). CONCLUSION: Combined imaging of the extensor tendons with both modalities is superior to either modality alone for predicting the presence of pathologic findings on histology. KEY POINTS: • Combination of B-mode US and SEL proved efficiency in diagnosing lateral epicondylitis. • Combination of B-mode US and SEL in lateral epicondylitis correlates to histology. • Combination of both modalities provides improved sensitivity without loss of specificity.

New laparoscopic approach to the pudendal nerve for neuromodulation based on an anatomic study.

AIMS: The aim was to develop a new laparoscopic technique for placement of a pudendal lead. METHODS: Development of a direct, feasible and reliable minimal-invasive laparoscopic approach to the pudendal nerve (PN). Thirty-one embalmed human specimens were dissected for the relevant anatomic structures of the pelvis. Step-by-step documentation and analysis of the laparoscopic approach in order to locate the PN directly in its course around the medial part of the sacrospinous ligament and test this approach for feasibility. Landmarks for intraoperative navigation towards the PN as well as the possible position of an lead were selected and demonstrated. RESULTS: The visible medial umbilical fold, the intrapelvine part of the internal pudendal artery, the coccygeus muscle and the sacrospinous ligament are the main landmarks. The PN traverses the medial part of the sacrospinous ligament dorsally, medially to the internal pudendal artery. The medial part of the sacrospinous ligament has to be exposed in order to display the nerve. An lead can be placed ventrally on the nerve or around it, depending on the lead type or shape. CONCLUSIONS: A precise and reliable identification of the PN by means of laparoscopy is feasible with an easy four-step approach: (1) identification of the medial umbilical fold; (2) identification of the internal iliac artery; (3) identification of the internal pudendal artery and incision of the coccygeus muscle ('white line', arcuated line); and (4) exposition of the medial part of the sacrospinous ligament to display the PN.

The Pathway of Injectate Spread With the Transmuscular Quadratus Lumborum Block: A Cadaver Study.

BACKGROUND: The spread of injectate resulting from a transmuscular quadratus lumborum (TQL) block and a transverse oblique paramedian (TOP) TQL block has never been examined. The aim of this cadaveric study was to investigate by which pathway the injectate spreads cephalad into the thoracic paravertebral space and which nerves were dyed by the injectate cephalad and caudad to the diaphragm when performing a TQL and a TOP TQL block. We also aimed to investigate whether the thoracic and lumbar sympathetic trunks as well as the lumbar plexus were covered by the injectate. METHODS: Ultrasound-guided bilateral TQL and TOP TQL injections were administered in 8 cadavers. A total of 16 injections were performed. With the TQL injection, the curvilinear transducer was oriented in the transverse plane above the iliac crest at the posterior axillary line to identify the Shamrock sign. With the TOP TQL injection, the same transducer was placed with a TOP orientation 3 cm lateral to the L2 spinous process to identify the L2 transverse process and the adjoining quadratus lumborum muscle. For both techniques, the needle was advanced in-plane to the transducer, with the end point in the interfascial plane between the quadratus lumborum and psoas major muscles. Thirty milliliters of dye solution was injected bilaterally for each technique. The spread of the dye was evaluated by subsequent dissection. RESULTS: In all successful injections, the dye was seen to spread into the thoracic paravertebral space and the intercostal spaces to surround the somatic nerves and the thoracic sympathetic trunk. The main pathway of spread of injectate was posterior to the medial and lateral arcuate ligaments. Caudad to the diaphragm, the injected dye surrounded the subcostal, iliohypogastric, and ilioinguinal nerves in all cases, whereas the genitofemoral and lateral femoral cutaneous nerves were dyed in a varying degree. No dye was seen to surround the lumbar plexus, femoral nerve, or lumbar sympathetic trunk. The pattern of spread was similar with the TQL and TOP TQL injections. CONCLUSIONS: The spread of injectate with the TQL and TOP TQL approaches is cephalad from the lumbar point of administration between the quadratus lumborum and psoas major muscles, predominantly via a pathway posterior to the arcuate ligaments and into the thoracic paravertebral space to reach the somatic nerves and the thoracic sympathetic trunk in the intercostal and paravertebral spaces. The lumbar plexus and lumbar sympathetic trunk are not affected.

Case report: a common trunk of the coronary arteries.

We describe the heart from a 79-year-old woman with no medical history of cardiac complaints. Her heart shows a regular right coronary artery (RCA) and a variant left coronary artery (LCA) arising from the right sinus of Valsalva. The common stem of the RCA and the LCA is extremely short. The LCA depicts a preinfundibular course with a cranial-anterior loop and reaches the intersection of the anterior interventricular sulcus and the left coronary sulcus, where it divides into the regular branches, the anterior interventricular branch (left anterior descending, LAD) and the circumflex branch (left circumflex, LCx). All further branching resembles a normal distribution with the posterior interventricular branch coming for the RCA. Such a variant LCA is extremely rare with a reported incidence of 0.17 %. However, recognition and angiographic demonstration of such a variation assume the highest priority in a patient undergoing, for instance, direct coronary artery surgery or prosthetic valve replacement.

Ultrasound-guided regional anesthesia: learning with an optimized cadaver model.

PURPOSE: To date, there have been few studies of the simulation of ultrasound-guided regional anesthesia for teaching purposes. The present study aimed to evaluate the visibility of nerves and their adjacent structures, and the feasibility of the use of ultrasound-guided blocks in specially prepared cadavers to develop a new teaching model. METHODS: Nerves of the brachial, lumbar, and sacral plexus were examined, and their visibility evaluated in 12 specially embalmed cadavers. Thereafter a needle was advanced under direct ultrasound guidance to target nerves, and selected blocks were imitated using saline. The model was evaluated with standardized questionnaires in two international workshops with 124 participants. RESULTS: The selected nerves were successfully identified in all cadavers. The typical ultrasound appearance of nerves and their adjacent structures was very similar to the echotexture of the living, and the spread of injected saline around nerves was comparable to that of local anesthetics used in live patients. 79 % of the participants completed the questionnaire and confirmed the value of this optimized teaching model. CONCLUSIONS: This cadaver model is a promising teaching tool for practicing both the visualization of nerves and the needle manipulation. Moreover, it is possible to simulate the interventional application and the spread of local anesthetics using saline. With the aim of maximizing the effectiveness of teaching, it is hoped that we, and others, may be able to establish the use of this kind of tool as a valuable adjunct to other models of teaching regional anesthesia.

The use of ultrasound improves the accuracy of epidural needle placement in cadavers.

PURPOSE: To investigate whether epidural-prepuncture ultrasound imaging improves the accuracy and quality of epidural needle placement or not? METHODS: By recruiting 15 cadavers, a total of 90 epidural needle punctures to access epidural space in study group with the help of ultrasound imaging at lumbar and thoracic spinal segments were attempted. A similar number of punctures in a control group were also performed without ultrasound imaging involving the intervertebral spaces adjacent to the ones used for ultrasound guided punctures. The accuracy of needle tip placement was ascertained with the help of computed axial tomography. Six variables: puncture depth and needle angle, procedure time, number of attempts per space, steps in needle advances, number of bony contacts and number of spaces attempted, were studied and compared among the groups. RESULTS: The accuracy of epidural needle placement and quality of the procedure in study group were superior to the control group. CONCLUSIONS: The pre-procedure ultrasound imaging enhances the accuracy and quality of epidural needle placement.

Distal subsartorial compartment block of the saphenous nerve - A dissection study and a patient case series.

STUDY OBJECTIVE: A saphenous nerve block is an important tool for analgesia after foot and ankle surgery. The conventional midthigh approach to saphenous nerve block in the femoral triangle may impede ambulation by impairing quadriceps motor function. PRIMARY OBJECTIVE: Developing a selective saphenous nerve block targeting the nerve distal to its emergence from the adductor canal in the subsartorial compartment. DESIGN: This study consists of A) a dissection study and B) Data from a clinical case series. SETTING: A) Medical University of Innsbruck, Austria (dissection of 15 cadaver sides) and. B) Aarhus University Hospital, Denmark (5 patients). INTERVENTIONS: A) Five mL of methylene blue was injected into the subsartorial compartment distal to the intersection of the saphenous nerve and the tendon of the adductor magnus guided by ultrasound. B) Five patients undergoing major hindfoot and ankle surgery had a subsartorial compartment block with 10 mL of local anesthetic in addition to a popliteal sciatic nerve block. MEASUREMENT: A) The frequencies of staining the saphenous and medial vastus nerves. B) Assessment of postoperative pain by NRS score (0-10) and success rate of saphenous nerve block by presence of cutaneous anesthesia in the anteromedial lower leg, and motor impairment by ability to ambulate. MAIN RESULTS: A) The saphenous nerve was stained in 15/15 cadaver sides. A terminal branch of the medial vastus nerve was stained in 2/15 cadaver sides. B) All patients were fully able to ambulate without support. No patients had any post-surgical pain from the anteromedial aspect of the ankle and foot (NRS score 0). The success rate of saphenous nerve block was 100%. CONCLUSION: The saphenous nerve can be targeted in the subsartorial compartment distal to the intersection of the nerve and the tendon of the adductor magnus. The subsartorial compartment block provided efficient analgesia without quadriceps motor impairment.

The Anterior Branch of the Medial Femoral Cutaneous Nerve Innervates Cutaneous and Deep Surgical Incisions in Total Knee Arthroplasty.

Background/Objectives: The intermediate femoral cutaneous nerve (IFCN), the saphenous nerve, and the medial femoral cutaneous nerve (MFCN) innervate the skin of the anteromedial knee region. However, it is unknown whether the MFCN has a deeper innervation. This would be relevant for total knee arthroplasty (TKA) that intersects deeper anteromedial genicular tissue layers. Primary aim: to investigate deeper innervation of the anterior and posterior MFCN branches (MFCN-A and MFCN-P). Secondary aim: to investigate MFCN innervation of the skin covering the anteromedial knee area and medial parapatellar arthrotomy used for TKA. Methods: This study consists of (1) a dissection study and (2) unpublished data and post hoc analysis from a randomized controlled double-blinded volunteer trial (EudraCT number: 2020-004942-12). All volunteers received bilateral active IFCN blocks (nerve block round 1) and saphenous nerve blocks (nerve block round 2). In nerve block round 3, all volunteers were allocated to a selective MFCN-A block. Results: (1) The MFCN-A consistently innervated deeper structures in the anteromedial knee region in all dissected specimens. No deep innervation from the MFCN-P was observed. (2) Sixteen out of nineteen volunteers had an unanesthetized skin gap in the anteromedial knee area and eleven out of the nineteen volunteers had an unanesthetized gap on the skin covering the medial parapatellar arthrotomy before the active MFCN-A block. The anteromedial knee area and medial parapatellar arthrotomy was completely anesthetized after the MFCN-A block in 75% and 82% of cases, respectively. Conclusions: The MFCN-A shows consistent deep innervation in the anteromedial knee region and the area of MFCN-A innervation overlaps the skin area covering the medial parapatellar arthrotomy. Further trials are mandated to investigate whether an MFCN-A block translates into a clinical effect on postoperative pain after total knee arthroplasty or can be used for diagnosis and interventional pain management for chronic neuropathic pain due to damage to the MFCN-A during surgery.

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.