Bifid Pancreatic Tail: an Anatomical Case Series and their Classification

Anomalies and variants of development of the pancreas are relatively frequent. Bifid pancreatic tail is a rare anatomic variation with only a few cases reported in the literature. The present case series were encountered during dissection of 50 anatomical specimens of the pancreas, spleen, and duodenum. We observed four unusual cases (8%) of bifid pancreatic tail. One case was of a vertically oriented bifid pancreas tail (2%), in another case, the tails here horizontally oriented (2%) and in two cases the bifid tails were horizontally oriented but unequal (4%). The bifid tails had an arterial supply that penetrated the glands between the tails and two out of four were also supplied by the superior horizontal pancreatic artery of Popova. The ductal system usually bifurcated at the level of the tails, but a case of trifurcation was also encountered. The current cases should be taken into account in hepato-pancreato-biliary surgery to avoid misdiagnosis and to comprehensively assess the patient preoperatively.

Abstract 1122‐000045: Transvenous Embolization of Vein of Galen Aneurismal Malformations Using the “Chapot Pressure Cooker” Technique

Introduction : There are various procedural techniques described in the literature to treat VGAM: 1) transarterial embolization (TAE) via a transfemoral or transumbilical approach, 2) transfemoral or transtorcular venous coiling, and 3) the combined transarterial and transvenous “trapping” of the fistula. The transarterial technique has permitted our team to obtain total or near‐total obliteration in approximately 80% of cases; however, there is a patient population in whom the residual arterial supply is comprised of small perforators. In these patients, transvenous embolization (TVE) is an attractive option, but its safety is unclear. Here we report the first two VGAM patients treated using the Chapot “pressure cooker” technique (ChPC). Methods : Two patients, one 5‐year‐old and one 7‐year‐old, both presented with congestive heart failure in the newborn period and were subsequently treated in the newborn period with multiple, staged TAEs with n‐BCA for choroidal VGAMs. We achieved progressive reduction in shunting and flow but were unable to accomplish complete closure of the malformation: in both patients, a small residual with numerous perforators persisted. The decision was made to perform transvenous embolization using the CHPC. In this technique, a guiding catheter is placed transjugular into the straight sinus (SS). One or two detachable tip microcatheters are advanced to the origin of the SS. Another microcatheter is advanced and the tip placed between the distal marker and the detachment zone of the former. Coils, and n‐BCA if necessary, are used to prevent reflux of Onyx. This forces the Onyx to occlude the vein and the most distal arterial segment. Results : Both patients had complete occlusion of the VGAM after ChPC. Conclusions : This is the first report to describe TVE to cure VGAM after multiple sessions of TAE. This is also the first report to apply ChPC to VGAM treatment. In this study, we recognized two important factors of traditional VGAM treatment that may cause interventionalists to consider the ChPC to treat VGAM: 1) without liquid embolic, deployed coils may not occlude the fistula entirely. 2) There is the concern of causing delayed bleeding should the arterial component of the fistula rupture. ChPC ameliorates these issues by offering complete closure of the fistula with liquid embolic material in TVE. Not only is the residual vein blocked, but also the incoming arterial supply which prevents delayed bleeding. In endovascular treatment of VGAM, TVE is feasible option once the dilated vein of Galen becomes small enough. To prevent incomplete occlusion or post‐procedural hemorrhagic complications, the use of the ChPC using DMSO liquid embolic material is a promising and necessary introduction to the neurointerventionalist’s treatment arsenal.

Abstract 1122‐000110: Transvenous Embolization in Vein of Galen Malformations as the Last Procedure

Introduction : Vein of Galen Malformations (VOGM) are a rare, congenital, vascular malformation representing <1% of all arteriovenous malformations. Treatment is typically performed in infancy and transarterial embolization (TAE) is the most common treatment method. While conventional methods allow for a total or near‐total obliteration in 80% of cases, there is a subset of patients for whom TAE is ineffective (E.g. the residual arterial supply is through small feeders non‐amenable to TAE). In these cases, transvenous embolization or coiling (TVE) is the technically simplest approach. We assessed the immediate angiographic and clinical outcomes of our VOGM cases treated with TVE. All relative technical details are reported. Immediate angiographic outcomes and clinical outcomes are reported. Methods : A retrospective review of our institutional database was performed to identify all VOGM patients who underwent TVE as the final‐stage procedure between January 2004 and December 2020. Results : We describe a cohort of 13 patients, one of whom underwent partial TVE for palliative measures and was excluded. All of the 12 patients that met our eligibility criteria had undergone more than 3 transarterial embolizations with nBCA. The mean age of our cohort was 8.2 (SD: 6.3) years. Ten patients were treated with coils and two with the Chapot “Pressure cooker” (ChPC) Technique. In these two cases, predicting hemorrhage post‐procedurally proved difficult; as a result, we attempted to occlude the remaining arterial supply using transvenous ChPC. Complete immediate angiographic obliteration was achieved in nine patients. Stereotactic radiosurgery was performed in 2 of the remaining patients and full obliteration was achieved. Immediate post‐procedural (within 48 hours) hemorrhagic complications were noted in two patients treated with coils: one of these ended in mortality and the second suffered from significant neurological impairment. In total, eight patients had normal development, three had a moderate delay with hemiparesis and one patient died. Conclusions : To the best of our knowledge, this is the first report of TVE being used as a final‐stage cure attempt for VOGMs after multiple TAE sessions. We advocate that TVE for the treatment of VOGMs is a feasible option as a final‐stage attempt for cure. It is particularly effective if the dilated VOG becomes small enough. To prevent incomplete occlusion and reduce the risk of post‐procedural hemorrhagic complications, the ChPC technique using liquid embolic material should be considered.

Development of the Arterial Supply of the Spinal Cord Tissue Based on Radioanatomical and Histological Studies in Cattle

Purpose Angiographic techniques have gained increasing importance in suspected vascular disease of the spinal cord. This demands an advanced understanding of spinal cord blood vessel anatomy and its embryologically founded broad spectrum of variations. The aim of this study was to improve knowledge on contentious issues concerning the development of spinal cord arterial supply in higher mammals and to offer visual information of high didactic value. Methods The prenatal development was examined in cattle, using multiplanar high-resolution microangiography of injected specimens and microscopic sections. The gestational ages of the 15 specimens were between the late embryonic and the early fetal period (5–11 weeks). Microangiography of the human spinal cord from an earlier published study were used to envisage an adult arterial vascularization pattern in higher mammals. Results Establishment of the unpaired anterior spinal artery (ASA) goes through two procedures of reconfiguration until achieving its final design. Regression of the primarily established anteromedian tract is observed in cattle fetuses of 9–10 weeks. Return to the ontogenetic disposition of bilateral symmetry and a burst of vascularization from all parts of the spinal meninges follow and include the anterior median fissure as a preferred vascular pathway. Large sulcal/central arteries longitudinally anastomosing between each other emerge on both sides of the midline. The embryological pattern of exclusive peripheral medullary supply must have been converted into a combined system of predominant central (centrifugal) supply of the enlargements before a final unpaired ASA can be reconstructed. Conclusion Previous investigators focused on the early embryonic development of spinal cord arteries and missed the profound remodeling of the vascular architecture in the early fetal period.

469 Novel Applications of Cross-Sectional Imaging in Oncoplastic Surgical Planning for Breast Cancer Following Neoadjuvant Chemotherapy

Background Cross-sectional imaging using MRI is most commonly used to evaluate the response to neoadjuvant chemotherapy. Furthermore, CT scan of chest, abdomen, and pelvis (CAP) is used in staging the breast cancer. This study seeks to evaluate the feasibility of using preoperative cross-sectional imaging in oncoplastic surgical planning for patients undergoing neoadjuvant chemotherapy for breast cancer. Method All female patients who underwent neoadjuvant chemotherapy for breast cancer between January 2019 and January 2020 and underwent breast MRI pre- and post-neoadjuvant chemotherapy and staging CTCAP were included. All images were independently reviewed and analysed by two consultant breast radiologists. Chest wall symmetry, breast volume differences, skin flap thickness, arterial supply to nipple, intercostal perforators and LD pedicle were assessed on both CT and MRI. Results Nineteen women were included in this study. Breast measurements were best made by MRI due to difficulty interpreting the CT images when supine. The majority of the patients had a dual arterial supply. There was substantial inter–observer agreement in visualisation of MICAP and AICAP. The inter–observer reliability reduced when the radiologists were asked to visualize the LICAP and the thoracodorsal artery with moderate inter–observer agreement, as the MRI images were difficult to interpret laterally. Conclusions This study shows that MRI is suitable to detect most intercostal perforators and is the first study to highlight cross-sectional modalities for assessment of intercostal perforators and may aid preoperative surgical planning and choice of perforator. We have suggested potential addition of CT angiography in cases where the surgeon plans oncoplastic surgery.