The role of the absence of Hyrtl's anastomosis in monochorionic pregnancy: Friend or foe?: A case report.

INTRODUCTION: Hyrtl's anastomosis, an intra-arterial shunt, plays a protective role when the placental territories supplied by the umbilical arteries are different in size. Its absence is associated with an increased risk of poor outcomes in singleton pregnancy. However, the literature and studies on the effect of absent Hyrtl's anastomosis in twin placentas are rare. CASE PRESENTATION: We present a case of a monochorionic diamniotic twin pregnancy complicated with type I selective fetal growth restriction (SFGR). Despite discordance in placental territory and cord insertion sites, the patient had an overall good pregnancy process, suggesting that the absence of Hyrtl's anastomosis may have played a benign role. CONCLUSIONS: The absence of Hyrtl's anastomosis in our case seemed to show a favorable effect, representing a finding of opposite effects in monochorionic placentas compared with singleton placentas.

The role of nailfold capillaroscopy in pediatric patients with Kawasaki disease.

BACKGROUND: Nailfold capillaroscopy has been used as a non-invasive diagnostic method for microvasculature evaluation in various rheumatological disorders. The present study aimed to determine the utility of nailfold capillaroscopy in the diagnosis of Kawasaki Disease (KD). METHOD: In this case-control study nailfold capillaroscopy was performed in 31 patients with KD and 30 healthy controls. All nailfold images were evaluated for capillary distribution and capillary morphology such as enlargement, tortuosity, and dilatation of the capillaries. RESULT: Abnormal capillaroscopic diameter was identified in 21 patients from the KD group and 4 patients in the control group. The most common abnormality in capillary diameter was irregular dilatation in 11 (35.4%) KD patients and in 4 people (13.3%) in the control group. Distortions of the normal capillary architecture was commonly seen in the KD group (n=8). A positive correlation was observed between coronary involvement and abnormal capillaroscopic results (r=.65, P<.03). The sensitivity and specificity of capillaroscopy for the diagnosis of KD were 84.0% (95%CI: 63.9-95.5%) and 72.2% (95%CI: 54.8-85.8%), respectively. The PPV and NPV of capillaroscopy for KD were 67.7% (95%CI: 48.6-83.3) and 86.7% (95% CI: 69.3-96.2), respectively. CONCLUSION: Capillary alterations are more common in KD patients compared to control group. Thus, nailfold capillaroscopy can be useful in detecting these alterations. Capillaroscopy is a sensitive test for detecting capillary alternations in KD patients. It could be used as a feasible diagnostic modality for evaluating microvascular damage in KD.

Laser doppler flowmetry to detect pulp vitality, clinical reference range and coincidence rate for pulpal blood flow in permanent maxillary incisors in Chinese children: a clinical study.

BACKGROUND: A laser doppler flowmetry (LDF) test can reflect the pulp vitality caused by the change in pulp blood flow (PBF). This study aimed to investigate the PBF of the permanent maxillary incisors using LDF and to calculate the clinical reference range and coincidence rate for pulp vitality using PBF as an indicator. METHODS: School-age children (7-12 years) were recruited randomly. A total of 455 children (216 female and 239 male) were included in this study. An additional 395 children (7-12 years) who attended the department due to anterior tooth trauma from October 2015 to February 2018 were included to assess the clinical occurrence rate. The PBF was measured using LDF equipment and an LDF probe. RESULTS: The clinical reference range of PBF values for the permanent maxillary incisors (teeth 11, 12, 21, and 22) in children were from 7 to 14 perfusion units (PU), 11 (6.016; 11.900 PU), 12 (6.677; 14.129 PU), 21 (6.043;11.899 PU), and 22 (6.668; 14.174 PU). There was a statistically significant correlation between PBF and children's age (p < 0.000) without any significant gender discrimination (p = 0.395). For all incisors, for any age group, the PBF detection value of the lateral incisors was significantly higher than that of the central incisors (p < 0.05). The clinical coincidence rate of detecting PBF in the traumatic teeth was 90.42% and the sensitivity and specificity were 36.99% and 99.88%, respectively. CONCLUSIONS: The determination of the PBF clinical reference range and clinical coincidence rate for the permanent maxillary incisors in children using LDF provided a promising theoretical basis for clinical applications.

Golden ratio in venation patterns of dragonfly wings.

The vein pattern in insect wings allows this lightweight structure to carry multiple biological functions. Here, an investigation of the angular distribution of the vein struts in dragonfly wings revealed that the golden angle or golden ratio dominates the venation patterns. We find that the golden angle dominates the intervein angles in regions where thin veins and membranes demand strength reinforcement. A golden ratio partition method has thus been developed that explains a set of preferred intervein angles in distorted polygon-shaped venation cells throughout the venation pattern in dragonfly wings. These observations provide new evidence that the wing structure is spatially optimized, by the golden rule in nature, for supporting biomechanical functions of dragonfly wings.

Understanding and Engineering the Pulmonary Vasculature.

Blood vessels play essential roles in regulating embryonic organogenesis and adult tissue homeostasis. The inner lining of blood vessels is covered by vascular endothelial cells, which exhibit tissue-specific phenotypes in term of their molecular signature, morphology, and function. The pulmonary microvascular endothelium is continuous and non-fenestrae to ensure stringent barrier function while allowing efficient gas exchange across the alveoli-capillary interface. During respiratory injury repair, pulmonary microvascular endothelial cells secrete unique angiocrine factors and actively participate in the molecular and cellular events mediating alveolar regeneration. Advances in stem cell and organoid engineering are offering new ways to produce vascularized lung tissue models to investigate vascular-parenchymal interactions during lung organogenesis and pathogenesis. Further, technology developments in 3D biomaterial fabrication are enabling construction of vascularized tissues and microdevices with organotypic features at high resolution to recapitulate the air-blood interface. In parallel, whole-lung decellularization produces biomaterial scaffolds with naturally occurring, acellular vascular bed with preserved tissue architecture and complexity. Emerging efforts in combining cells with synthetic or natural biomaterials open vast opportunities for engineering the organotypic pulmonary vasculature to address current limitations in regenerating and repairing damaged lungs and pave the way towards next-generation therapies for pulmonary vascular diseases.

Clinical Translation of Engineered Pulmonary Vascular Models.

Diseases in pulmonary vasculature remain a major cause of morbidity and mortality worldwide. Numerous pre-clinical animal models were developed to understand lung vasculature during diseases and development. However, these systems are typically limited in their ability to represent human pathophysiology for the study of disease and drug mechanisms. In recent years, a growing number of studies have focused on developing in vitro experimental platforms that mimic human tissues/organs. In this chapter, we discuss the key components involved in developing engineered pulmonary vascular modeling systems and provide perspectives on ways to improve the translational potential of existing models.

"Missing-piece" sign with dural arteriovenous fistula at craniocervical junction: A case report.

OBJECTIVES: Spinal dural arteriovenous fistula (sDAVF) is a rare and often underdiagnosed spinal disease. Early diagnosis is required because the deficits are reversible and delays in treatment cause permanent morbidity. Although the abnormal vascular flow void is a critical radiographic feature of sDAVF, they are not always present. A characteristic enhancement pattern of sDAVF has been recently reported as the "missing-piece" sign which can lead to the early and correct diagnosis. METHODS: We presented imaging findings, treatment decisions, and the outcome of a rare case of sDAVF, in which the "missing-piece" sign appeared atypical. RESULTS: A 60-year-old woman developed numbness and weakness in her extremities. Spinal MRI revealed longitudinal hyperintensity in the T2-weighted image, extending from the thoracic level to medulla oblongata. At first, myelopathy with inflammation or tumor was suspected because of the lack of flow voids and vascular abnormalities in CT-angiography and MR-DSA. However, we administered intravenous methylprednisolone and her symptom got worse with the appearance of the "missing-piece" sign. Then, we successfully diagnosed sDAVF by angiography. The "missing-piece" sign was considered to derive from inconsistency of the intrinsic venous system of spinal cord, with the abrupt segments without enhancement. The same etiology was considered in our case. CONCLUSIONS: Detecting the "missing-piece" sign can lead to the correct diagnosis of sDAVF, even if the sign appeared atypical.

[Application of folded transverse superficial epigastric artery perforator flap for large penetrating defect after buccal carcinoma resection].

Objective: To explore the effectiveness of folded transverse superficial epigastric artery perforator flap in repairing the large penetrating defect after buccal carcinoma resection. Methods: Between January 2019 and June 2021, 12 patients with buccal squamous cell carcinoma were treated. There were 6 males and 6 females with an average of 66.9 years (range, 53-79 years). The pathological stage was T3a-T4b, and the preoperative mouth opening was (3.08±0.46) cm. The disease duration ranged from 6 to 24 months, with an average of 15 months. After buccal carcinoma radical resection and neck lymph node dissection, the penetrating defects in size of 8 cm×6 cm to 16 cm×8 cm and in depth of 0.5-1.5 cm were remained. The transverse superficial epigastric artery perforator flap in size of 8 cm×6 cm to 14 cm×8 cm were harvested and folded to repair the penetrating defects. The donor site was sutured directly. Results: All 12 skin flaps survived after operation, and the wounds healed by first intention. No internal or external fistula complications occurred. All incisions at the recipient site healed by first intention. All patients were followed up 12-18 months (mean, 14 months). There was no obvious abnormality in the color and texture of the flap, the oral and facial appearances were symmetrical, and there was no obvious swelling in the cheek. At last follow-up, the patient's mouth opening was (2.89±0.33) cm, which was not significantly different from that before operation ( t=1.879, P=0.087). The subjective satisfaction scores of 12 patients were 6-8 points, with an average of 7.3 points. Significant scars remained at the donor site but concealed in location. Conclusion: The folded transverse superficial epigastric artery perforator flap can be used as a surgical method for repairing large penetrating defects after the buccal carcinoma resection, with a good recovery of facial appearance and oral function.

Scapho-luno-capitate fusion with proximal lunate articular surface preservation for management of grade IIIA Kienböck's disease: a prospective case series.

BACKGROUND: Kienböck's disease is idiopathic lunate avascular necrosis, which may lead to lunate collapse, abnormal carpal motion and wrist arthritis. The current study aimed to assess the outcomes of treating stage IIIA Kienböck's disease by a novel technique of limited carpal fusion via partial lunate excision with preservation of the proximal lunate surface and scapho-luno-capitate (SLC) fusion. MATERIALS AND METHODS: We conducted a prospective study of patients with grade IIIA Kienböck's disease managed with a novel technique of limited carpal fusion comprising SLC fusion with preservation of the proximal lunate articular cartilage. Autologous iliac crest bone grafting and K-wires fixation were used to enhance the osteosynthesis of the SLC fusion. The minimum follow-up period was 1 year. A visual analog scale (VAS) and the Mayo Wrist Score were utilized for the evaluation of patient residual pain and functional assessment, respectively. A digital Smedley dynamometer was used to measure the grip strength. The modified carpal height ratio (MCHR) was used for monitoring carpal collapse. The radioscaphoid angle, scapholunate angle, and the modified carpal-ulnar distance ratio were used for the assessment of carpal bones alignment and ulnar translocation of carpal bones. RESULTS: This study included 20 patients with a mean age of 27.9 ± 5.5 years. At the last follow-up, the mean range of flexion/extension range of motion (% of normal side) improved from 52.8 ± 5.4% to 65.7 ± 11.1%, P = 0.002, the mean grip strength (% of normal side) improved from 54.6 ± 11.8% to 88.3 ± 12.4%, P = 0.001, the mean Mayo Wrist Score improved from 41.5 ± 8.2 to 81 ± 9.2, P = 0.002, and the mean VAS score reduced from 6.1 ± 1.6 to 0.6 ± 0.4, P = 0.004. The mean follow-up MCHR improved from 1.46 ± 0.11 to 1.59 ± 0.34, P = 0.112. The mean radioscaphoid angle improved from 63 ± 10º to 49 ± 6º, P = 0.011. The mean scapholunate angle increased from 32 ± 6º to 47 ± 8º, P = 0.004. The mean modified carpal-ulnar distance ratio was preserved and none of the patients developed ulnar translocation of the carpal bones. Radiological union was achieved in all patients. CONCLUSIONS: Scapho-luno-capitate fusion with partial lunate excision and preservation of the proximal lunate surface is a valuable option for treating stage IIIA Kienböck's disease, with satisfactory outcomes. Level of evidence Level IV. Trial registration Not applicable.

Radial peripapillary capillary network in optic disc anomalies with abnormal tissues on disc surface.

Background: Optic disc anomalies with abnormal tissue on the disc surface includes, myelinated nerve fiber, optic disc drusen, and Bergmeister papillae. Imaging the radial peripapillary capillary (RPC) network in optic disc anomalies with optical coherence tomography-angiography (OCTA) can give information on the RPC network in these conditions. Purpose: This video describes the OCTA of optic nerve head and RPC network using the angio disc mode in cases of optic disc anomalies with abnormal tissue on the disc surface. Synopsis: This video presents characteristic features of RPC network in one eye each of myelinated nerve fiber, optic disc drusen, and Bergmeister papillae. Highlights: OCTA in optic disc anomalies with abnormal tissue on the disc surface show a dense RPC microvascular network. OCTA is an effective imaging modality to study vascular plexus/RPC and their alteration in these disc anomalies. Video link: https://youtu.be/zlflgijy56c.

Analysis of Blood Flow in the Macula and Optic Nerve Head in Healthy Young Volunteers Using Laser Speckle Flowgraphy.

PURPOSE: To assess optic nerve head (ONH) and macular blood flow in young healthy volunteers using laser speckle flowgraphy (LSFG). METHODS: This is a prospective single-center study conducted at the Department of Ophthalmology, University Hospital Zurich from May to November 2021. Young, healthy men aged ≥ 18 years without ocular or systemic diseases were included. A corrected visual acuity (VA) of 0.0 logMAR or better in both eyes and an intraocular pressure (IOP) of 21 mmHg or lower were required for inclusion. Subjects exceeding a spherical equivalent (SE) of ± 6 diopters (dpt) were excluded. Blood flow in the macula and the ONH was recorded using the Nidek LSFG RetFlow device (Nidek Company, Ltd., Hirioshi-cho, Japan). Laser power was set to 0.5 Millivolts (mV). Mean blur rate (MBR) was recorded as a parameter for blood flow. MBR is a calculated parameter that represents relative blood flow velocity correlated with the real anatomical blood flow rate. Colored heat maps of the recorded retinal area were generated automatically by the RetFlow device. RESULTS: Final analyses included 83 eyes of 43 male volunteers. Mean age was 21.9 years (SD ± 1.5, range: 20 to 29). Mean corrected VA was - 0.1 logMAR (SD ± 0.05, range: - 0.2 to 0.0), mean IOP was 15.4 mmHg (SD ± 2.5, range: 8.5 to 18.5), and mean SE was - 0.3 dpt (SD ± 1.2, range: - 5.0 to 1.2). Mean ONH MBR was 37.44 (SD ± 7.9, range: 22.5 to 53.5) and mean macular MBR was 27.8 (SD ± 9.7, range: 6.4 to 57.7). Pearson's Test showed a strong correlation between macular and papillary blood flow (p < 0.05, coefficient: 0.647). CONCLUSION: This study provides both ONH and macular blood flow data in a healthy young male population, showing a strong correlation between ONH and macular blood flow in the examined eyes. Further investigations are required to assess the validity of MBR as a parameter for the combined evaluation of retinal blood flow at the macula and ONH in healthy volunteers and patients with various diseases.

Is the origin of the superior thyroid artery consistent? A systematic review of 5488 specimens.

PURPOSE: The superior thyroid artery (STA) point of origin is strongly debated with controversial results among studies. External carotid artery (ECA), carotid bulb, and common carotid artery (CCA) have been presented as points of origin with variable percentages among authors. We conducted a systematic review of all existing studies that included cadaveric, surgical, and angiographic specimens and recorded the origin of STA according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. MATERIALS AND METHODS: Fifty-two studies, with an overall of 5488 specimens were included. RESULTS: Our results indicated ECA as the most common site of origin (55.0 %) followed by carotid bifurcation at 27.5 % and CCA at 15.0 %. Absent STA or branching from the internal carotid artery (ICA) was an extremely rare finding. We proposed a new simple classification system based on our results. CONCLUSIONS: The huge variability in the branching pattern of STA makes head and neck surgery and radiographic interventions challenging and poses the integrity of STA at risk. Therefore, we strongly recommend preoperative angiographic studies for STA identification to prevent an intraoperative iatrogenic injury.

Capillary-Mitochondrial Oxygen Transport in Muscle: Paradigm Shifts.

When exercising humans increase their oxygen uptake (V̇O2) 20-fold above rest the numbers are staggering: Each minute the O2 transport system - lungs, cardiovascular, active muscles - transports and utilizes 161 sextillion (10 21) O2 molecules. Leg extension exercise increases the quadriceps muscles' blood flow 100-times; transporting 17 sextillion O2 molecules per kilogram per minute from microcirculation (capillaries) to mitochondria powering their cellular energetics. Within these muscles, the capillary network constitutes a prodigious blood-tissue interface essential to exchange O2 and carbon dioxide requisite for muscle function. In disease, microcirculatory dysfunction underlies the pathophysiology of heart failure, diabetes, hypertension, pulmonary disease, sepsis, stroke and senile dementia. Effective therapeutic countermeasure design demands knowledge of microvascular/capillary function in health to recognize and combat pathological dysfunction. Dated concepts of skeletal muscle capillary (from the Latin capillus meaning 'hair') function prevail despite rigorous data-supported contemporary models; hindering progress in the field for future and current students, researchers and clinicians. Following closely the 100th anniversary of August Krogh's 1920 Nobel Prize for capillary function this Evidence Review presents an anatomical and physiological development of this dynamic field: Constructing a scientifically defensible platform for our current understanding of microcirculatory physiological function in supporting blood-mitochondrial O2 transport. New developments include: 1. Putative roles of red blood cell aquaporin and rhesus channels in determining tissue O2 diffusion. 2. Recent discoveries regarding intramyocyte O2 transport. 3. Developing a comprehensive capillary functional model for muscle O2 delivery-to-V̇O2 matching. 4. Use of kinetics analysis to discriminate control mechanisms from collateral or pathological phenomena.

Prospective observational study of clinical outcomes in using posterior interosseous free flap for finger defects.

Finger injuries are common in hand and plastic surgery practice. There are various options for reconstructing finger defects. Moderate sized skin defects of the fingers which need flaps are commonly covered using various abdominal flaps. These conventional workhorse flaps are thick, need two-staged procedures and require the hand to be kept in a cumbersome position. The radial artery or the ulnar artery flap need sacrifice a major vessel. To address the above, we have used the posterior interosseous artery free flap to cover finger defects. This was a prospective observational clinical study done on 15 patients admitted to a tertiary level hospital from July 2017 to July 2021. These patients had accidental industrial injuries with a loss of soft tissue on the fingers. There were finger fractures in 6 cases. These patients underwent posterior interosseous artery free flap cover. The flap size ranged from 6 × 3 cm to 10 × 4 cm. We had to cover the donor defects with skin graft in all our cases. Fourteen out of 15 flaps survived, with loss of one flap due to venous congestion. The mean two-point discrimination was 7.8 mm, with a total active motion percentage of more than 70% in 11 out of 15 cases. The posterior interosseous artery flap is a thin and pliable one stage flap, and may not need further flap thinning either, thereby establishing itself as a single stage procedure and moreover not requiring sacrifice a major vessel.

Role of perforator flaps in leg and foot reconstruction.

INTRODUCTION: Lower extremity wounds have always been a challenge for the reconstructive surgeons. Free perforator flaps are considered to be the best option for this problem but require the complexity of microsurgery. So, pedicled perforator flaps have emerged as an alternative option. PATIENTS AND METHODS: Prospective study was conducted in 40 patients with traumatic soft tissue defects in the leg and foot. The free flaps included the anterolateral thigh flap (ALT) and medial sural artery perforator flap (MSAP). In pedicled perforator flaps group, 10 cases were designed as propeller flaps while the other 10 flaps were designed as perforator plus flaps. RESULTS: Free flaps were mainly used for large-sized defects; we had one case of partial flap loss and one case of complete flap necrosis.  MSAP flap was the first option for coverage of large-sized defects on foot and ankle as it is a thin and pliable flap, while ALT flap was used for coverage of larger defects on the leg. Pedicled perforator flaps were used mainly for small to medium-sized defects, especially in the lower third of the leg; we had three cases of flap loss in propeller flap design while we had no cases of flap loss in perforator plus flap. CONCLUSION: Perforator flaps have become a reasonable solution for soft tissue defects of the lower extremity. Careful assessment of the dimensions, location, patient comorbidities, availability of surrounding soft tissue and presence of adequate perforators are mandatory for proper perforator flap selection.

[Monitoring during Cerebrovascular Surgery].

Intraoperative monitoring of cerebrovascular disease is performed in direct surgery and endovascular treatment to prevent complications due to blood flow disturbance. Typical surgeries in which monitoring is useful are revascularization surgeries, such as bypass, carotid endarterectomy, and aneurysm clipping surgery. Revascularization is performed to normalize intracranial and extracranial blood flow but requires interruption of blood flow to the brain, even for a short time. Changes in cerebral circulation and function when blood flow is blocked cannot be generalized because they are affected by collateral circulation and differ among cases. Monitoring is important to understand these changes during surgery. It is also used in revascularization procedures to check if the reestablished cerebral blood flow is adequate. Changes in monitoring waveforms can detect the emergence of neurological dysfunction, but in some cases, clipping surgery can end with missing waveforms, leading to dysfunction. Even in such cases, it can help identify which surgery caused the malfunction and improve the outcome of subsequent surgeries.

Vascular Anatomy and Variations of the Anterior Abdominal Wall - Significance in Abdominal Surgery.

Detailed knowledge of the human anatomy is an integral part of every surgical procedure. The majority of surgery related complications are due to a failure to possess appropriate knowledge of human anatomy. However, surgeons pay less attention of the anatomy of the anterior abdominal wall. It is composed of nine abdominal layers, which are composed of fascias, muscles, nerves, and vessels. Many superficial and deep vessels and their anastomoses supply the anterior abdominal wall. Moreover, anatomical variations of these vessels are often presented. Intraoperative and postoperative complications associated with entry and closure of the anterior abdominal wall could compromise the best surgical procedure. Therefore, sound knowledge of the vascular anatomy of the anterior abdominal wall is fundamental and a prerequisite to having a favourable quality of patient care. The purpose of the present article is to describe and delineate the vascular anatomy and variations of the anterior abdominal wall and its application in abdominal surgery. Consequently, the most types of abdominal incisions and laparoscopic accesses will be discussed. Furthermore, the possibility of vessels injury related to different types of incisions and accesses will be outlined in detail. Morphological characteristics and distribution pattern of the vascular system of the anterior abdominal wall is illustrated by using figures either from open surgery, different types of imaging modalities or embalmed cadaveric dissections. Oblique skin incisions in the upper or lower abdomen such as McBurney, Chevron and Kocher are not the topic of the present article.

Individualized design of thoracodorsal artery perforator chimeric flap for customized reconstruction of complex three-dimensional defects in the extremities.

BACKGROUND: It was always challenging to accurately and effectively reconstruct the complicated defects with three-dimensional tissue deficits in the extremities. Muscle-chimeric perforator flap is an excellent choice for repairing those complicated wound. However, problems like donor-site morbidity and time-consuming intramuscular dissection still exist. This purpose of this study was to present a novel design of the thoracodorsal artery perforator (TDAP) chimeric flap for the customized reconstruction of complex three-dimensional tissue defects in the extremities. METHODS: From January 2012 to June 2020, 17 patients with complex three-dimensional deficits in the extremities were retrospectively analyzed. All patients in this series underwent extremity reconstruction using latissimus dorsi (LD)-chimeric TDAP flap. Three different types of LD-chimeric TDAP flaps were performed. RESULTS: A total of seventeen TDAP chimeric flaps were successfully harvested for the reconstruction of those complex three-dimensional defects in extremities. Among them, Design Type A flaps were used in 6 cases, Design Type B flaps were performed in 7 cases, and Design Type C flaps were used in the remaining 4 cases. The sizes of the skin paddles ranged from 6 cm × 3 cm to 24 cm × 11 cm. Meanwhile, the sizes of the muscle segments ranged from 3 cm × 4 cm to 33 cm × 4 cm. All the flaps survived. Nevertheless, one case required re-exploration owing to venous congestion. Moreover, the primary closure of the donor site was successfully achieved in all patients, and the mean follow-up time was 15.8 months. Most of the cases displayed satisfactory contour. CONCLUSION: The LD-chimeric TDAP flap is available for the reconstruction of complicated defects with three-dimensional tissue deficits in the extremities. It provided a flexible design for customized coverage of complex soft tissue defects with limited donor site morbidity.