Area Of Dissection Research Articles

Morphometric and anatomic characteristics of pronator quadratus muscle

PurposeIn surgical procedures commonly employed for the management of scaphoid and distal radial fractures, the incision and dissection of the pronator quadratus muscle play a pivotal role. Nevertheless, comprehensive investigations into the anatomical intricacies of the pronator quadratus muscle have been relatively scarce within the clinical community. In light of this, our study endeavors to make a substantive contribution to the medical literature by conducting a meticulous examination of the morphology and morphometry of this muscle. MethodsThis study is a cross-sectional observational study conducted on 22 cadaveric upper extremities (44 sides) preserved between January 2005 and December 2018 at Istanbul University. The study included specimens with intact dissection areas and no prior surgical intervention. Observations focused on the morphometry of the pronator quadratus muscle and related anatomical structures. Statistical analysis was performed using SPSS v23.0, employing Student's t-test and paired t-test, with significance set at p < 0.05. ResultsSignificant differences were found in the morphometric measurements of the pronator quadratus muscle between the right and left upper extremities, particularly in the vertical distance between the proximal and distal attachment points of the pronator quadratus to the radius (p = 0.008). Additionally, significant differences were observed between male and female samples for radius length (p < 0.001), ulna length (p < 0.001), pronator quadratus width (p < 0.001), and the vertical distance between pronator quadratus attachment points on both the radius (p = 0.001) and ulna (p = 0.001). Furthermore, significant correlations were identified between radius length and parameters such as the vertical distance between pronator quadratus attachment points on both the radius (p = 0.002) and pronator quadratus width (p = 0.03), and between ulna length and parameters including the vertical distances on the radius (p = 0.001) and ulna (p = 0.024). ConclusionIn light of our comprehensive analysis, which encompasses not only the anatomical features of the pronator quadratus muscle but also its vascular supply and the organization of its neurovascular structures, we posit that our study holds significant implications for the field of orthopedic surgery. We anticipate that this research will furnish valuable insights that can inform and enhance orthopedic procedures.

Outcomes of adjuvant lymph node field radiotherapy and immunotherapy for stage III melanoma

PurposeWith the promising results of immunotherapy in patients with stage III melanoma, the role of adjuvant radiotherapy after resection and complete lymph-node dissection must be reassessed. We evaluate the outcomes and safety of adjuvant radiotherapy and immunotherapy compared to immunotherapy only in patients with resected stage III melanoma. Patients and methodsThis retrospective and single institution study included patients treated for a stage III melanoma with complete lymph-node dissection and adjuvant immunotherapy from January 2019 to December 2022. The radiotherapy associated with immunotherapy group was defined by completion of immunotherapy and adjuvant radiotherapy in the lymph-node dissection area. The primary endpoint was disease-free survival. The secondary endpoints were locoregional progression, incidence of adverse events grade 3 or above and disease-free survival rate in patients with high risk of locoregional recurrence. ResultsThirty-three patients were included. Among them, twelve received adjuvant lymph-node field radiotherapy. The median duration of follow-up was 17months (range: 8–45months). Patients receiving radiotherapy and immunotherapy had a significantly higher disease stage and more frequent extracapsular extension. At 12months, the disease-free survival rate was 66.7% for the patients receiving immunotherapy alone (95% CI: 42.5–82.5%) and 83.3% for those receiving radiotherapy and immunotherapy (95% CI: 48.2–95.6%; P=0.131). The locoregional progression rate was 24% in patients receiving immunotherapy and 8% in patients receiving immunotherapy and radiotherapy (P=0.379). After adjuvant treatment, 6% of patients developed grade 3 or above immunotherapy-related events and none developed grade 3 or above radiation-related adverse events. ConclusionIn patients with stage III melanoma, adjuvant lymph-node field radiotherapy combined with immunotherapy seems to be associated with longer disease-free survival, with acceptable tolerance. However, these results need to be confirmed by long-term and prospective studies.

Radiological assessment of the dissection area in supraomohyoid neck dissection

PurposeThe current supraomohyoid neck dissection (SOHND) is performed above the omohyoid muscle to dissect levels I, II, and III in the levels of cervical lymph nodes. However, the anatomical boundary between levels III and IV is the inferior border of the cricoid cartilage. We investigated the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT) images to assess the validity of the current SOHND.MethodsCE-CT images of the head and neck regions in patients were reviewed. The patients were divided into two groups: “malignant tumors” and “others”. The vertebral levels corresponding to the positions of anatomical structures such as the intersection of the omohyoid muscle and internal jugular vein (OM-IJ), and the inferior border of the cricoid cartilage (CC), were recorded.ResultsThe OM-IJ was located around the seventh cervical to the first thoracic vertebra. There was a significant difference between the malignant tumor and others groups in females (p = 0.036). The CC was located around the sixth to seventh cervical vertebrae. There was a significant sex difference in each group (malignant tumor: p < 0.0001; others: p = 0.008). Both sexes tended to have lower OM-IJ than CC, and females had significantly lower OM-IJ than males.ConclusionThis study provides clear anatomical evidence showing the difference between the SOHND dissection area and levels I, II, and III. It could be considered that in most cases SOHND invades level IV, not just levels I, II, and III, especially in female patients.

Step ladder VY advancement flap for lower eyelid reconstruction after resection eyelid malignant tumors

BackgroundIn oculoplastic surgery, reconstruction of a large defect after the removal of a massive malignant lower lid tumor still represents a unique challenge. We will report on this case, including a presentation of the case using step ladder V–Y advancement flap.MethodsDuring November 2018 to March 2023, five patients of lower eyelid malignant tumor had wide resection with safety margin and reconstructed using step ladder V–Y advancement flap. The flap was used step ladder V–Y advancement flap.ResultsNo complications, including ectropion deformity, occurred. This flap does not sacrifice healthy skin as seen with the cheek rotation flap, and the area of dissection is very small and can be performed in a short time.ConclusionsStep ladder V–Y advancement flap is highly useful in cases that require a reconstruction of a large defect after the removal of a massive malignant lower lid tumor from viewpoints of operating time, ease of procedure, aesthetics, and complications.

What is the Optimal Proximal Landing Zone of the Stent Graft in Treatment of Aortic Type B Dissection?

Retrograde type A aortic dissection (RTAD) represents a serious complication of endovascular treatment for type B aortic dissection (TBAD). To avoid RTAD, it is recommended to land the proximal end of the stent graft in a non-dissected aortic segment. In this study, we investigated whether landing in the dissection area increased the number of events at the proximal site. We conducted a retrospective review of endovascular treatments for TBAD at a single institution between 2009 and 2022. Patients were divided into two groups: group A, with a proximal landing zone entirely within the dissected area, and group B, with the proximal extent of the seal zone in the non-dissected area. We evaluated the occurrence of proximal events, including RTAD, and examined long-term outcomes to assess the validity of landing in the dissection area. The study included eighty-nine patients who underwent endovascular treatment for TBAD. New intimal tears in the proximal landing site occurred in 3 cases (3.4%), with 1 case (2%) in group A and 2 cases (5.1%) in group B, showing no significant difference. Among the three cases, one (1.1%) in group B with zone 2 landing resulted in RTAD. At 60months, the overall survival was 85%, and freedom from aorta-related mortality was 88%, with no significant difference between the groups. Even if the proximal landing is in a dissected area, a treatment strategy performed in zone 3 without proximal landing in zone 2, seeking a non-dissected area, can still provide sufficient therapeutic effects. Level of Evidence 3 Retrospective single-center cohort analysis.

Recurrence of rectal cancer on the pelvic sidewall after lateral lymph node dissection

PurposeAlthough lateral lymph node dissection has been performed to prevent lateral pelvic recurrence in locally advanced lower rectal cancer, the incidence of lateral pelvic recurrence after this procedure has not been investigated. Therefore, this study aimed to investigate the long-term outcomes of patients who underwent lateral pelvic lymph node dissection, with a particular focus on recurrence patterns.MethodsThis was a retrospective study conducted at a single high-volume cancer center in Japan. A total of 493 consecutive patients with stage II-III rectal cancer who underwent lateral lymph node dissection between January 2005 and August 2022 were included. The primary outcome measures included patterns of recurrence, overall survival, and relapse-free survival. Patterns of recurrence were categorized as lateral or central pelvic.ResultsAmong patients who underwent lateral lymph node dissection, 18.1% had pathologically positive lateral lymph node metastasis. Lateral pelvic recurrence occurred in 5.5% of patients after surgery. Multivariate analysis identified age > 75 years, lateral lymph node metastasis, and adjuvant chemotherapy as independent risk factors for lateral pelvic recurrence. Evaluation of the recurrence rate by dissection area revealed approximately 1% of recurrences in each area after dissection.ConclusionWe demonstrated the prognostic outcome and limitations of lateral lymph node dissection for patients with advanced lower rectal cancer, focusing on the incidence of recurrence in the lateral area after the dissection. Our study emphasizes the clinical importance of lateral lymph node dissection, which is an essential technique that surgeons should acquire.

Robotic spleen‑preserving suprapancreatic and splenic hilar lymph node dissection using the preemptive retropancreatic approach in total gastrectomy for gastric cancer.

Advanced gastric cancer that has not invaded the greater curvature is a good indication for total gastrectomy (TG) with spleen-preserving suprapancreatic and splenic hilar lymph node dissection (LND). However, the suprapancreatic and splenic hilar LND increases the area of dissection of the pancreas, and prolonged pressure drainage of the pancreas is required to maintain a clear operative view. This can lead to an increased risk of postoperative pancreatic complications. To report the efficacy of our novel preemptive retropancreatic approach (PRA) for the suprapancreatic and splenic hilar LND in robotic TG (RTG). We report our experience with nine patients with gastric cancer who underwent spleen-preserving splenic hilar LND using PRA during RTG at Hokkaido University from October 2018 to November 2021. The PRA involves initial dissection of the left side of the retropancreatic space, followed by the release of the adherence between the retroperitoneum surface and the pancreas (fusion fascia), which provides a good operative field and prevents contact with the pancreas during the suprapancreatic and splenic hilar LND in RTG. The median operating time was 488min (254-564min). The median intraoperative bleeding was 55mL (0-115mL). One patient had postoperative complications (above grade II of the Clavien-Dindo classification), but there were no postoperative pancreatic complications. The spleen-preserving suprapancreatic and splenic hilar LND using PRA could help to reduce the postoperative pancreatic complications associated with RTG.Trial registration number and date of registration The Hokkaido University Hospital institutional review board approved the data collection and analysis. The trial registration number and date of registration are No. 021-0022 and July 26, retrospectively registered.

Laparoscopic modified e-tep repair of concomitant inguinal and ventral hernias.

Laparoscopic hernia repair in recent times has gained the most acceptance among both the surgical community and the patient groups, as it has proven benefits of lesser postoperative hospital stay and less pain scores. The incidence of both inguinal and ventral hernias has increased significantly in the present days. Various methods have been postulated by different surgical groups for repairing the same but no there is no standard consensus on managing concomitant inguinal and ventral hernias. The conventional e-TEP requires an extensive dissection with increased operative time. We present our experience in managing cases with both inguinal and primary M2/M3 and W1 ventral hernias with or without divarication of recti using a modified up to down approach for inguinal hernia followed by down to up approach for the ventral hernia, from a tertiary care center in South India. We managed 16 cases with simultaneous incidence of inguinal and primary M2/M3 and W1 ventral hernias with or without divarication of recti between January 2022 and November 2023. Institute ethical committee clearance and informed consent was obtained from all the 16 patients. They were all subjected to an extra peritoneal repair of both the hernias. All the demographic data, intraoperative data, postoperative complications and follow up were digitally stored. All patients were followed up for six months after surgery. Out of 16 patients, 15 were males and 1 was female. The mean age was 48years and the mean BMI of all the patients was 29.2kg/m2. The postoperative recovery was smooth in all patients and being discharged within 24h after surgery. The pain scores of all patients were significantly lower than patients who underwent intraperitoneal repair. e-TEP hernia repair is gaining popularity and has amused the hernia surgical community. Our method of e-TEP RS repair in cases with concomitant inguinal and primary M2/M3 W1 ventral hernias with or without divarication helps in addressing both the hernias in the extra-peritoneal space. Our technique reduces the area of dissection needed for mesh placement and preserves the integrity of abdominal musculature in the upper abdomen when compared with the conventional technique. It further allows extension of the e-TEP inguinal space into the Rectro rectus space without much alteration in the port arrangement allowing simultaneous repair of groin and umbilical hernias. Good knowledge of anatomy and laparoscopic skills are pertinent for safe and effective hernia repair by this technique.

A Novel Retractable Robotic Device for Colorectal Endoscopic Submucosal Dissection.

: Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). In this study, we developed a retractable robot-assisted traction device and evaluated its performance in colorectal ESD. : An experienced endoscopist performed ESD 18 times on an ex vivo porcine colon using the robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate. : Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robot-assisted ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 minutes vs 34.3±8.3 minutes, p<0.05). The submucosal dissection speed was significantly faster in the RESD group than in the CESD group (36.8±9.2 mm2/min vs 18.1±4.7 mm2/min, p<0.05). The blind dissection rate was also significantly lower in the RESD group (12.8%±3.4% vs 35.1%±3.9%, p<0.05). In an in vivo porcine feasibility study, the robotic device was attached to a colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed. : The dissection speed and safety profile improved significantly with the retractable RESD. Thus, our robotic device has the potential to provide simple, effective, and safe multidirectional traction during colonic ESD.

Approach to a patient with iatrogenic coronary dissection during percutaneous intervention

This case report presents a conservative management approach to a potentially hazardous complication, iatrogenic coronary artery dissection (ICAD), occurring during percutaneous coronary intervention (PCI). The patient, a 60-year-old woman with a history of chronic hypertension and type II diabetes mellitus, presented with non-ST-segment elevation myocardial infarction. During the PCI, an antegrade coronary dissection was observed, leading to the termination of the procedure. Post-procedure, the patient was managed conservatively with standard coronary artery disease treatment. Follow-up angiography showed complete healing of the dissection area, and no adverse cardiovascular events occurred during a 3-month follow-up period. This report highlights the importance of early diagnosis and careful management of ICAD. It stresses the need for further research into long-term outcomes and effectiveness of different treatment approaches for patients with ICAD.

Management and outcomes of spontaneous coronary artery dissection: a systematic review of the literature.

Contemporary management of spontaneous coronary artery dissection (SCAD) is still controversial. This systematic review of the literature aims to explore outcomes in the patients treated with conservative management vs. invasive strategy. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed when we extensively searched three electronic databases: PubMed, ScienceDirect, and Web of Science, for studies that compared conservative vs. invasive revascularization treatment outcomes for patients with SCAD from 2003 to 2023. The outcomes of interest were all-cause death and major adverse cardiovascular events (MACE), including acute coronary syndrome (ACS), heart failure (HF), need for additional revascularization, target vessel revascularization (TVR), SCAD recurrence, and stroke. The systematic review included 13 observational studies evaluating 1,801 patients with SCAD. The overall mean age was 49.12 +/- 3.41, and 88% were females. The overall prevalence of arterial hypertension was 33.2%, hyperlipidemia, 26.9%, smoking, 17.8%, and diabetes, 3.9%. Approximately 48.5% of the patients were diagnosed with non-ST elevated myocardial infarction (NSTEMI), 36.8% with ST elevated myocardial infarction (STEMI), 3.41% with unstable angina, 0.56% with stable angina, and 0.11% were diagnosed with various types of arrhythmias. The left anterior descending artery (LAD) was the most common culprit lesion in 51% of the patients. There were initially 65.2% of conservatively treated patients vs. 33.4% that underwent percutaneous coronary intervention (PCI) or 1.28% that underwent coronary artery bypass graft (CABG). SCAD-PCI revascularization was associated with a variable range of PCI failure. The most common complications were hematoma extension and iatrogenic dissection. SCAD-PCI revascularization frequently required three or more stents and had residual areas of dissection. The overall reported in-hospital and follow-up mortality rates were 1.2% and 1.3%, respectively. The follow-up range across studies was 7.3-75.6 months. The authors reported variable prevalence of MACE, recurrent SCAD up to 31%, ACS up to 27.4%, TVR up to 30%, repeat revascularization up to 14.7%, UA up to 13.3%, HF up to 17.4%, and stroke up to 3%. Our results highlight that conservative treatment should be the preferred method of treatment in patients with SCAD. PCI revascularization is associated with a high prevalence of periprocedural complications. SCAD poses a considerable risk of MACE, mainly associated with TVR, ACS, and recurrent SCAD.

Standardization of robot-assisted pelvic lymph node dissection-Development of a common understanding of regional anatomy and surgical technique based on cross-disciplinary discussion among colorectal surgery, urology, and gynecology.

Pelvic lymph node dissection is a procedure performed in gastroenterological surgery, urology, and gynecology. However, due to discrepancies in the understanding of pelvic anatomy among these departments, cross-disciplinary discussions have not been easy. Recently, with the rapid spread of robotic surgery, the importance of visual information in understanding pelvic anatomy has become even more significant. In this project, we attempted to clarify a shared understanding of pelvic anatomy through cross-disciplinary discussions. From May 2020 to November 2021, a total of 11 discussions were held entirely online with 5 colorectal surgery specialists, 4 urologists, and 4 gynecologists. The discussions focused on evidence from each specialty and surgical videos, aiming to create a universally understandable pelvic anatomical illustration. The common area of dissection recognized across the three departments was identified as the obturator lymph nodes. A dynamic illustration of pelvic anatomy was created. In addition to a bird's-eye view of the pelvis, a pelvic half view was developed to enhance understanding of the deeper pelvic anatomy. The following insights were incorporated into the illustration: (1) the cardinal ligament in gynecology partly overlaps with the vesicohypogastric fascia in colorectal surgery; (2) the obturator lymph nodes continue cephalad into the fossa of Marcille in urology; and (3) the deep uterine vein in gynecology corresponds to the inferior vesical vein in colorectal surgery. Based on the dynamic illustration of pelvic anatomy from cross-disciplinary discussions, we anticipate advancements in pelvic lymph node dissection aiming for curative and safe outcomes.

Impact of tumor stage and neoadjuvant chemotherapy in fluorescence-guided lymphadenectomy during laparoscopic gastrectomy for gastric cancer: A propensity score-matched study in a western center

BackgroundThe use of indocyanine green fluorescence has been shown to be a safe and effective method for improving lymph node retrieval in patients with gastric cancer. However, previous studies have focused on early-stage tumors and/or the Asian population and excluded patients who received neoadjuvant treatment. MethodsIn this study, 142 patients with gastric adenocarcinoma underwent laparoscopic gastrectomy at a Spanish hospital between January 2017 and December 2022. Of these, 42 patients received preoperative indocyanine green injection to guide lymphadenectomy. Their outcomes were compared to a retrospective cohort of 42 patients after 1:1 propensity score matching. ResultsThe feasibility of indocyanine green lymphatic mapping was 95.5%. No complications associated with indocyanine green injection were observed. The indocyanine green group had a significantly higher number of retrieved lymph nodes than the non-indocyanine green group (32.67 vs 25.14; P = .013). This statistically significant difference was maintained across subgroups of neoadjuvant treatment, non-obese patients, pT0 to 2 stage, and pN0 stage. In 47.6% of patients from the indocyanine green group, lymphadenectomy was extended outside the standard D2 dissection area based on indocyanine green uptake, but none of the retrieved lymph nodes were metastatic. There were no differences in postoperative complications and length of hospital stay between the 2 groups. ConclusionIndocyanine green-guided lymphadenectomy is safe and feasible and increases the number of retrieved lymph nodes compared to conventional lymphatic dissection, as well as in patients receiving neoadjuvant chemotherapy. The use of indocyanine green should be routine if available for guiding lymph node dissection in gastric cancer, regardless of tumor stage or previous neoadjuvant treatment. However, further studies are needed to determine the impact of this technique on disease-free and overall survival.

Stent assisted coil embolization for a dissecting cerebral aneurysm of middle cerebral artery: A case report and the literature review

Background: Dissecting aneurysms of the middle cerebral artery (MCA) are very rare. We herein report a case of an unruptured dissecting aneurysm of the MCA treated by stent-assisted coil embolization. Case Description: A 65-year-old man with no history of trauma presented with a headache. Time-of-flight imaging revealed a dissecting cerebral aneurysm in the right M1 segment of the MCA, and the aneurysm had increased in size within a short time. We treated the aneurysm by endovascular stenting with coils, and the patient developed no neurological deficits. Conclusion: Because of the potential involvement of the lenticulostriate artery (LSA) in the area of dissection, choosing the best treatment (such as direct surgery or endovascular treatment) may be challenging. Treatment efficacy depends on whether the LSA is affected and on the length of the dissection. In our case, the dissection did not involve the LSA and could therefore be treated by stent-assisted coil embolization.

The Wonder Dye: Uses and Implications of Indigocyanine Green in Various Surgeries.

Indigocyanine green (ICG) is a fluorophore dye that has been extensively used in recent modern times for bioimaging in numerous surgeries to aid in easier identification of occult and often tricky-to-find anatomical structures. Surgery becomes complex and challenging due to multiple anatomical anomalies, pathological fibrosis, obesity, or previous surgeries. To overcome these obstacles in surgery, the surgeon yearns to know the structures present beyond their white light vision so that while dissecting the organ, they can avoid injuring the critical systems in the vicinity of dissection. Near-infrared (NIR) imaging aids in visualising the tissues at depth/in the area of dissection, thereby preventing any possible surgical catastrophes due to them inadvertently damaging surrounding vital structures. Various advantages in surgeries like gastric sleeve surgery, lymph node and tumour detection, localisation of ureters and biliary tracts, and intraoperative tissue perfusion of flaps have been described in this study. This review article aims to compile a short list of utilities of ICG with NIR imaging in various surgical interventions. The merits and demerits of this imaging technique have been noted. The study points out the uses of ICG fluorescence imaging under different surgical fronts. This review article concludes by comparing the results of studies performed by various authors. Results have been compared to conventional surgical modalities.

Temporal Facelift: A New Method for Temporal and Mid-face Lifting.

Lifting the temporal and mid-face areas creates a very dynamic change in the facial appearance and different planes of dissection were described before. In this article, a new plane of dissection is described which allows the surgeon to perform a very quick and safe dissection in both the temporal and mid-face regions. Patients were operated on using the presented technique and brow lift, cantopexy, and mid-facelift were performed. The outcome of the surgery was analyzed by the authors from standardized photos before and 6 months after the surgery with measurements of the brow and lateral canthus. The plane of dissection is just over the subgaleal fascia which is actually the sub-superficial musculoaponeurotic system layer in the mid-face. This plane of dissection is easy and quick and creates a very mobile mid-face and temporal flap. Forty female patients were operated using the presented technique with a mean follow-up period of 15 months, the longest follow-up was 26 months. No major complication was encountered in these patients. In 5 patients, transient unilateral frontal branch palsy was encountered. In 1 patient, bilateral temporal area depression was observed 8 months after the surgery and treated with a fat injection under local anesthesia. One patient had alopecia in the temporal suture line which can be covered with hair. Temporal facelift is a versatile method with long-lasting results due to its important features; creating a very mobile flap for suspension dissection area, a large surface for adherence, and numerous sutures sharing the tension on the key sutures. Despite its slightly difficult early healing period, the technique should be kept in mind for the rejuvenation of the periorbital area and mid-face. Level of Evidence: Level I.

Artificial Intelligence for context-aware surgical guidance in complex robot-assisted oncological procedures: An exploratory feasibility study

IntroductionComplex oncological procedures pose various surgical challenges including dissection in distinct tissue planes and preservation of vulnerable anatomical structures throughout different surgical phases. In rectal surgery, violation of dissection planes increases the risk of local recurrence and autonomous nerve damage resulting in incontinence and sexual dysfunction. This work explores the feasibility of phase recognition and target structure segmentation in robot-assisted rectal resection (RARR) using machine learning. Materials and methodsA total of 57 RARR were recorded and subsets of these were annotated with respect to surgical phases and exact locations of target structures (anatomical structures, tissue types, static structures, and dissection areas). For surgical phase recognition, three machine learning models were trained: LSTM, MSTCN, and Trans-SVNet. Based on pixel-wise annotations of target structures in 9037 images, individual segmentation models based on DeepLabv3 were trained. Model performance was evaluated using F1 score, Intersection-over-Union (IoU), accuracy, precision, recall, and specificity. ResultsThe best results for phase recognition were achieved with the MSTCN model (F1 score: 0.82 ± 0.01, accuracy: 0.84 ± 0.03). Mean IoUs for target structure segmentation ranged from 0.14 ± 0.22 to 0.80 ± 0.14 for organs and tissue types and from 0.11 ± 0.11 to 0.44 ± 0.30 for dissection areas. Image quality, distorting factors (i.e. blood, smoke), and technical challenges (i.e. lack of depth perception) considerably impacted segmentation performance. ConclusionMachine learning-based phase recognition and segmentation of selected target structures are feasible in RARR. In the future, such functionalities could be integrated into a context-aware surgical guidance system for rectal surgery.

Essential updates 2021/2022: Perioperative and surgical treatments for gastric and esophagogastric junction cancer.

In recent years, important clinical trials for gastric cancer (GC) and esophagogastric junction cancer (EGJC) have been reported, changing the strategies of surgical and perioperative treatment. Although laparoscopic gastrectomy has already been shown to be effective for early-stage cancer, recent evidence from both Asia (JLSSG0901, CLASS-01 and KLASS-02) and Europe (LOGICA and STOMACH trials) has demonstrated that it is useful for advanced GC. Robotic surgery has been rapidly gaining popularity in recent years, and randomized controlled trials are ongoing to evaluate its efficacy. A prospective nationwide multicenter study mapped sites with frequent metastasis and revealed lymphatic flow specific to EGJC, thus establishing the optimal lymph node dissection area and surgical approach based on esophageal involvement. Perioperative chemotherapy, the mainstay of treatment in Europe, also has been established in Asia by the PRODIGY and RESOLVE studies. New clinical trials have been conducted to evaluate the efficacy of combining immunotherapy or molecular-targeted therapy with perioperative chemotherapy or chemoradiotherapy. In this review, we present important recent clinical trials regarding the treatment of GC and EGJC published in 2021 or 2022.

Masseteric Nerve Ultrasound Identification for Dynamic Facial Reanimation Purposes.

The masseteric nerve is one of the main options to neurotize free muscle flaps in irreversible long-term facial paralysis. Several preoperative skin-marking techniques for the masseteric nerve have been proposed to limit the surgical dissection area, shorten the surgical time, and enable a safer dissection. However, these have shown variability among them, and cannot visualize the nerve preoperatively. The authors designed an observational study to validate a high-frequency ultrasound (HFUS) nerve identification technique. A systematic HFUS examination was designed and performed to visualize the masseteric nerve in 64 hemifaces of healthy volunteers. One-third were randomly selected to undergo an additional HFUS-guided needle electrostimulation to validate the HFUS image. The masseteric nerve was identified by HFUS in 96.9% of hemifaces (95% CI, 0.89 to >0.99) and showed almost perfect agreement with direct needle stimulation as calculated with Cohen kappa coefficient (0.95; 95% CI, 0.85 to 1.00). The masseteric nerve was found within the masseter muscle, in between the deeper muscle bellies, at 18.3 mm (SD ±2.2) from the skin. Only in 12.9% of cases (95% CI, 0.06 to 0.24) did its course become adjacent to the mandible periosteum. Other important features, such as disposition in relation to the parotid gland, or if the nerve was covered directly by a thick intramuscular aponeurosis, could be well observed by HFUS. HFUS enables masseteric nerve identification and can provide the surgeon with specific information on anatomical relations for each examined individual before surgery.

Abnormal flow pattern of low wall shear stress and high oscillatory shear index in spontaneous vertebral artery dissection with vertebral artery hypoplasia.

Spontaneous vertebral artery dissection (sVAD) might tend to develop in vertebral artery hypoplasia (VAH) with hemodynamic dysfunction and it is crucial to assess hemodynamics in sVAD with VAH to investigate this hypothesis. This retrospective study aimed to quantify hemodynamic parameters in patients with sVAD with VAH. Patients who had suffered ischemic stroke due to an sVAD of VAH were enrolled in this retrospective study. The geometries of 14 patients (28 vessels) were reconstructed using Mimics and Geomagic Studio software from CT angiography (CTA). ANSYS ICEM and ANSYS FLUENT were utilized for mesh generation, set boundary conditions, solve governing equations, and perform numerical simulations. Slices were obtained at the upstream area, dissection or midstream area and downstream area of each VA. The blood flow patterns were visualized through instantaneous streamline and pressure at peak systole and late diastole. The hemodynamic parameters included pressure, velocity, time-averaged blood flow, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), endothelial cell action potential (ECAP), relative residence time (RRT) and time-averaged nitric oxide production rate (TARNO). Significant focal increased velocity was present in the dissection area of steno-occlusive sVAD with VAH compared to other nondissected areas (0.910 m/s vs. 0.449 vs. 0.566, p < 0.001), while focal slow flow velocity was observed in the dissection area of aneurysmal dilatative sVAD with VAH according to velocity streamlines. Steno-occlusive sVAD with VAH arteries had a lower time-averaged blood flow (0.499 cm3/s vs. 2.268, p < 0.001), lower TAWSS (1.115 Pa vs. 2.437, p = 0.001), higher OSI (0.248 vs. 0.173, p = 0.006), higher ECAP (0.328 Pa-1 vs. 0.094, p = 0.002), higher RRT (3.519 Pa-1 vs. 1.044, p = 0.001) and deceased TARNO (104.014 nM/s vs. 158.195, p < 0.001) than the contralateral VAs. Steno-occlusive sVAD with VAH patients had abnormal blood flow patterns of focal increased velocity, low time-averaged blood flow, low TAWSS, high OSI, high ECAP, high RRT and decreased TARNO. These results provide a good basis for further investigation of sVAD hemodynamics and support the applicability of the CFD method in testing the hemodynamic hypothesis of sVAD. More detailed hemodynamic conditions with different stages of sVAD are warranted in the future.