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Background and AimsStellate ganglion block (SGB) is conventionally performed at the C6 vertebral level; however, this method poses the risk of accidental nerve blockade and vascular injury. We propose a novel approach, first-rib neck SGB (1RN-SGB), that effectively minimises these risks (figure 1).Methods[Case series] Ten patients underwent 1RN-SGB with 3–5 mL of 1% lidocaine after confirmation of contrast imaging using 3–4 mL of iohexol. Clinical outcomes, adverse effects, and extent of contrast spread were recorded. [Cadaveric study] 1RN-SGB was performed on four Thiel-embalmed cadavers (six sides) with 3 or 6 mL of 0.4% indigo carmine injected. Dye spread and nerve involvement were assessed by dissection.Results[Case series] 1RN-SGB successfully achieved pain relief in all patients with Horner’s sign. Two patients reported paralysis of the ulnar side of the hand and forearm. No additional adverse events were reported. Contrast spread reached adjacent to the T1 vertebra (figure 2). [Cadaveric study] The stellate ganglion was completely stained with 6 mL of dye but only on the lateral surface by 3 mL (figure 3). The sympathetic trunk was consistently stained at C7-T2. Recurrent laryngeal, vagus, and phrenic nerves were not stained. C8 and T1 nerves were stained in all cadavers.Abstract EP158 Figure 1The ultrasound image and the procedure of 1RN-SGB[Image Omitted. See PDF.]Abstract EP158 Figure 2The contrast spread after injection of 4 mL of iohexol[Image Omitted. See PDF.]Abstract EP158 Figure 3The dye spread after injection of 3 mL of 0.4% indigo carmine[Image Omitted. See PDF.]ConclusionsAlthough 1RN-SGB demonstrates consistent effects, its pathway may differ from that of conventional SGB. 1RN-SGB effectively reduces severe complications; however, it is crucial to note the unintentional blockade of C8 and T1 nerves.

Background and AimsThis pilot cadaveric study aimed to evaluate the role of anatomical asymmetry in the thoracic paravertebral space (TPVS) and gravitational forces on dye-spread during bilateral TPVB performed in the lateral position.MethodsThe study was approved by the Ethics Committee of Sapporo Medical University between January 2022 and August 2024 (Nos. 3–1–61, 4–1–49, and 6–1–39). Twelve soft-embalmed Thiel cadavers were used: six were placed in the left-lateral position and six in the right-lateral position. A single-injection of 20 mL dye was administered to each TPVS using an ultrasound-guided intercostal approach. After 20 min, the cadavers were repositioned in a supine position. The vertebral segmental numbers of stained TPVSs and intercostal spaces (ICSs) were recorded.ResultsTPVB performed on the left side demonstrated significantly more stained segments (median [interquartile range]) than that performed on the right side (TPVS: 4.0 [3.0–5.0] vs. 2.0 [1.0–3.0], p = 0.01; ICS: 4.0 [3.0–5.0] vs. 3.0 [2.0–4.0], p = 0.04). However, no significant differences in dye-spread were observed between the upper and lower sides (TPVS: 4.0 [1.0–5.0] vs. 2.0 [2.0–5.0], p = 0.63; ICS: 4.0 [2.0–4.0] vs. 3.0 [2.0–5.0], p = 0.69).ConclusionsWe demonstrated that the larger volume of the left TPVS compared with the right TPVS may contribute to a more extensive spread, whereas gravitational forces appear to be minimal. Our findings suggest that a larger volume of local anesthetic may be required on the right side to achieve analgesia comparable to that on the left side.

Objectives: This study aims to evaluate the accuracy of morphometric measurements obtained from cadavers and anteroposterior (AP) pelvic radiographs. Methods: A total of 15 cadavers from the anatomical collection of Cukurova University and 217 AP pelvic radiographs from individuals aged 65-80 years with no orthopedic conditions were analyzed. Morphometric measurements were taken from cadavers using Kirschner wires placed at anatomical reference points: the spina iliaca anterior superior (SIAS), the highest point of the crista iliaca (CI), and the trochanter major (TM). Distances were measured with a non-elastic tape, and angular measurements were conducted using ImageJ software. These were compared with radiographic data analyzed via the PACS system. Statistical analysis was performed using SPSS 20 with One-Way ANOVA to assess group differences. Results: The mean age was 70.98±4.70 years for radiograph individuals and 80.36±5.13 years for cadavers. Significant differences were found between cadaveric, dissected cadaver, and radiological measurements. The SIAS-TM distance was longest in cadavers (113.82±7.46 mm) and shortest in radiographs (92.73±14.36 mm). The CI-TM distance was greatest in radiographs (147.81±12.02 mm), while the SIAS-CI distance was longest in cadavers (78.95±6.48 mm). Differences in SIAS-TM (P<0.001), CI-TM (P=0.007), and SIAS-CI (P=0.029) distances were statistically significant. Angular measurements also varied, with radiographs showing higher SIAS angles and cadavers showing greater TM and CI angles, especially on the right side. Conclusions: The study reveals notable discrepancies between cadaveric and radiological morphometric measurements. These cadaver-based findings may serve as valuable resources for surgical training and anatomical education, especially in hip arthroplasty planning.

Category: Hindfoot; Other Introduction/Purpose: There are few comparative studies between the traditional triple arthrodesis and the commonly performed modified procedure in which the calcaneocuboid joint is spared. Earlier investigations proposed that stiffening the lateral column of the hindfoot can increase lateral plantar pressures, potentially precipitating lateral column pain. We used a cadaver model to quantify the potential for reduced lateral column overload achieved by sparing the calcaneocuboid joint in a cadaveric model of triple arthrodesis simulating standing on both a neutral and sloping surface. Methods: Nine fresh-frozen, thawed cadaver legs were tested in 2 positions of the loaded surface: neutral and 10 degrees of eversion. Tendon loading and axial pressure was applied according to standard cadaveric models. Medial and lateral forefoot pressures were recorded using a pressure-sensitive plate (F-scan). The data were normalized as a percentage of the native state. Results: In neutral loading, the mean contact pressures under the fifth metatarsal head increased dramatically compared to the native state in both the standard (76.3%, p<.005) and calcaneocuboid-sparing (103.5%, p<.007) procedures. Pressure was reduced underneath the first metatarsal head medially in both standard (-52.8%, p< 0.017) and calcaneocuboid-sparing (-57.2%, p< 0.008). Loading on an everted surface yielded larger overall pressures laterally, but the further increases compared to the native state following both standard (39.0%, p < 0.04) and calcaneocuboid-sparing (57.9%, p< 0.03) procedures were smaller than in the neutrally loaded foot. No statistically significant difference was observed between the arthrodesis groups when loaded either on a neutral or sloped surface. Conclusion: In our cadaveric model, both traditional triple arthrodesis and the calcaneocuboid-sparing procedure resulted in significant elevation of lateral forefoot plantar pressures compared to the native state, but there was no identifiable protective effect from sparing the calcaneocuboid joint even in the provocative condition of loading on a sloping surface. Clinical Relevance: While other factors may guide the choice to spare the calcaneocuboid joint when performing hindfoot fusion, there is no evidence that preserving its motion significantly reduces the risk of lateral column overload.

Category: Midfoot/Forefoot Introduction/Purpose: Lisfranc injuries are a relatively common midfoot injury involving the tarsometatarsal (TMT) joint. Surgical fixation typically involves open reduction with internal fixation or primary arthrodesis of the joint(s). The standard surgical approach to the TMT joint involves two dorsal incisions however, a recent study has suggested the use of a modified single dorsal incision approach. The goal of this paper is to compare the total surface area of the joint that can be prepared for primary arthrodesis of the TMT using the standard vs modified single dorsal approach. Methods: Ten fresh frozen below-the-knee cadaver specimens were randomly assigned to receive either the standard or modified dorsal single incision operative approach to the TMT joint. Prior to initiating the study, specimens were inspected with fluoroscopic radiographs for preexisting pathology or prior surgical intervention. The joint surface was visualized and then underwent articular preparation as for a joint fusion. After adequate joint preparation, the TMT joint was disarticulated and the surface was photographed for image analysis. Using ImageJ, articular joint surface preparation areas were measured by two blinded reviewers. to assess the joint surface preparation and this was compared by surgical approach. Results: After ImageJ and Mann-Whitney U statistical analysis, there was no significant difference in the amount of joint prepared when comparing the standard versus modified dorsal approach for the first three TMT joints (p= 0.548, p=0.310, p= 0.548). The percentage of joint preparation utilizing the standard dorsal approach versus the modified dorsal approach for TMT joints one through three are as follows (percentages utilized are listed as the median value with its correlating range): First TMT- 67.6% (range 26%) by the standard approach versus 71.7% (range 9%) by the modified dorsal approach, second TMT- 67.9% (range 24%) versus 65.7% (range 12%), and third TMT- 65.9% (range 42%) versus 59.6% (range 24%). Table 1 summarizes our results between each operative approach. Conclusion: With our findings, we demonstrate that a modified single dorsal approach to the Lisfranc joint provided comparable joint preparation for primary arthrodesis as the standard dual incision approach. However, the modified dorsal approach may be beneficial in that it avoids creating a skin bridge which has potential for necrosis with the standard two incision approach. The authors believe the comparable joint preparation combined with its potential to alleviate soft tissue complications make the modified dorsal approach a viable surgical approach for a TMT arthrodesis.

Background and AimsBlocks of the individual nerves in the forearm is well established, but data regarding the spread of local anesthetics is scarce/infrequent. Based on the cadaveric injection of latex in the following nerves- Median (MN), Ulnar (UN), and Superficial radial The primary aim was to evaluate the latex spread, circumferential or non-circumferential. The secondary aim was to investigate the dye diffusion in muscles, paraneural, epineural tissue, longitudinal spread along the nerve, and anatomic barriers.MethodsWith 6 soft embalmed cadavers (12 specimens), a total of 36 injections were performed. At a point, 5 cm from the elbow crease 1) 5 ml of blue latex was injected in close vicinity of the MN. 2) 5 ml of green latex was injected between the ulnar artery and the UN. 3) 5 ml of green latex was injected close to the SRN. After injection, all specimens were dissected, and the three nerves were traced from the elbow crease to the wrist joint.ResultsThe blue latex disintegrated into various thin bands, though remaining in the same plane of FDP and FDS in the close vicinity of the median nerve. Beneath the brachioradialis and superficial to ECRL, a greenish discoloration was observed, which encroached upon the bicipital aponeurosis. The superficial radial nerve was engulfed significantly than the deep radial nerve. 9 figures 1,2,3) Deep to the flexor carpi ulnaris (FCU), the green latex spread linearly along the ulnar nerve and the ulnar artery.ConclusionsBased on our cadaveric injection study, we recommend a forearm nerve block at ‘5 cm’ distal to the elbow crease. We conclude that in the forearm nerves, a non-circumferential, longitudinal spread pattern is consistent with a ‘3 ml’ latex injection. The lateral antebrachial cutaneous and the medial cutaneous nerves of the forearm were spared and would require separate injections.Abstract EP039 Figure 1Median nerve dissection in a cadaver[Image Omitted. See PDF.]Abstract EP039 Figure 2Radial nerve dissection in a cadaver[Image Omitted. See PDF.]Abstract EP039 Figure 3Ulnar nerve dissection in cadaver[Image Omitted. See PDF.]

Background and AimsAnkle blocks are often given for calcaneal fractures. They involve blocking five nerves using multiple injections. The objective of this cadaveric study is to identify the interfacial planes traversed by the nerves innervating the calcaneum.MethodsSix fresh human cadavers (12 specimens) were used in the study. To investigate the innervation of calcaneum, foot dissection was done in three cadavers (6 specimens) to delineate the nerves of the foot, in specific inter-fascial planes. In other 3 cadavers (6 specimens), ultrasound-guided dye injections were performed in specific inter-fascial planes and diffusion of dye was evaluated. Open dissection was performed in 3/6 specimens and cross-section in 3/6 specimens.ResultsThe nerves on the medial side were situated between the proximal attachment of abductor hallucis and quadratus plantae. On the lateral aspect, the skin and subcutaneous tissue over the calcaneum were innervated by the sural nerve and its branches in the subcutaneous tissue immediately lateral to the tendo-Achillis. (Figure 1) After reflecting the abductor hallucis, lateral, medial, and posterior tibial nerves were unstained (4/6). In contrast, the inferior calcaneal nerve and sural nerve were stained in all specimens. (6/6) In the coronal cross-section, the epimysium of the abductor hallucis was well preserved. The epimysium and medial plantar nerve were not stained.Abstract EP118 Figure 1Dissection finding and delineation of various nerves supplying calcaneum[Image Omitted. See PDF.]ConclusionsOur cadaveric study suggests the possibility of a two-point injection technique to instil administer a site-specific local anaesthetic to block nerves supplying calcaneum. However, future clinical research based on our cadaveric study should be done to validate our findings further and make it a clinically proper technique.

Background and AimsParavertebral block (PVB) achieves anesthesia by injecting local anesthetic beneath the superior costotransverse ligament (SCTL), targeting the anterior ramus of the spinal nerve. Although PVB typically affects multiple thoracic levels, the mechanism underlying this spread remains controversial. It is often attributed to a ‘paravertebral space,’ yet no anatomically distinct space has been definitively described. This study aimed to determine the actual anatomical route responsible for local anesthetic spread during PVB.MethodsTwo embalmed cadavers were dissected through the internal thoracic wall. At the 7th intercostal space, the neurovascular bundle was identified between the anterior and posterior components of the SCTL. After careful removal of the intercostal artery and vein, the spinal nerve located beneath the superior rib was exposed. Methylene blue dye was injected using a paravertebral approach at the 6th intercostal space. The spread of the dye was subsequently evaluated by dissection, focusing on its course through the intervertebral foramen and adjacent structures.ResultsIn both cadavers, the dye extended from the medial aspect of the spinal ganglion toward the spinal nerve, indicating spread from the epidural space. In the first specimen, surrounding connective and adipose tissue were removed to reveal the spinal ganglion and rami communicantes. Dye distribution filled the intercostal groove from medial to distal. In the second specimen, the posterior SCTL was broader, and the anterior component again covered the ganglion; the dye followed a similar path.Abstract P167 Figure 1Dissection to anterior of SCTL, spinal ganglion and nerve inspect from anterior chest wall[Image Omitted. See PDF.]Abstract P167 Figure 2After dye injection[Image Omitted. See PDF.]ConclusionsAlthough anatomically there is no true paravertebral space, this study demonstrated that multi-segmental—and occasionally contralateral—spread may occur via lateral extension of the epidural space beneath the SCTL. The presumed wedge-shaped paravertebral space appears not to be cranio-caudal but instead represents segmental projections of the epidural space. Larger cadaveric studies are warranted to validate these findings.