Anatomical variations in the pattern of the right hepatic veins: possibilities for type classification

A morphological study of the right hepatic veins (RHVv) was conducted based on the shape and the confluence pattern of the superior right hepatic vein (SRHV) and the presence of accessory right hepatic veins. The study was performed in 110 undamaged, randomly selected, cadaveric human livers prepared using the corrosion cast methodology. The principles for classifying the RHVv into types were as follows: the length of the vein trunk, the confluence of 2 or 3 main tributaries that form a trunk, and the accessory right hepatic veins that modify the venous drainage of the right side of the liver. Four types of SRHV were identified. Type 1 (20 %), type 2 (40 %) and type 3 (25 %) were the most common, while type 4 (15 %) was linked to the accessory right hepatic veins in cases where they drain a surgically important part of the liver. Accessory right hepatic veins were found in a total of 31 casts (28 %). The hepatocaval confluence was studied and the tributary-free part of the SRHV trunk before it entered the inferior vena cava was measured. The tributary-free part of the SRHV was longer than 1 cm in 77 % of the casts. Anastomoses between the terminal tributaries of the veins involved in the drainage of the right side of the liver were also investigated.

Pancreas transplantation with portal venous drainage with an emphasis on technical aspects

Advances in surgical techniques and clinical immunosuppression have led to improving results in vascularized pancreas transplantation. Most pancreas transplants are performed with enteric exocrine drainage and systemic venous delivery of insulin (systemic-enteric technique) although bladder drainage (systemic-bladder technique) remains a viable option. To improve the physiology of pancreas transplantation, an innovative technique of portal venous delivery of insulin and enteric drainage of the exocrine secretions (portal-enteric technique) was developed and refined over the past 27 yr. However, the potential of portal-enteric pancreas transplantation has never been fully realized as it is currently performed in only 18% of simultaneous pancreas-kidney/sequential pancreas after kidney and 10% of pancreas-alone transplants with enteric drainage. A number of studies have demonstrated no major or consistent differences in outcomes for bladder-drained or enteric-drained pancreas transplants with either portal or systemic venous drainage although some studies suggest purported metabolic and immunologic advantages associated with portal venous delivery of insulin. The purpose of this study is to review the existing literature on portal-enteric pancreas transplantation with an emphasis on surgical aspects and technical modifications/nuances that have been introduced with time and experience.

A venous mechanism of ventriculomegaly shared between traumatic brain injury and normal ageing

Recently, age-related timing dissociation between the superficial and deep venous systems has been observed; this was particularly pronounced in patients with normal pressure hydrocephalus, suggesting a common mechanism of ventriculomegaly. Establishing the relationship between venous drainage and ventricular enlargement would be clinically relevant and could provide insight into the mechanisms underlying brain ageing. To investigate a possible link between venous drainage and ventriculomegaly in both normal ageing and pathological conditions, we compared 225 healthy subjects (137 males and 88 females) and 71 traumatic brain injury patients of varying ages (53 males and 18 females) using MRI-based volumetry and a novel perfusion-timing analysis. Volumetry, focusing on the CSF space, revealed that the sulcal space and ventricular size presented different lifespan profiles with age; the latter presented a quadratic, rather than linear, pattern of increase. The venous timing shift slightly preceded this change, supporting a role for venous drainage in ventriculomegaly. In traumatic brain injury, a small but significant disease effect, similar to idiopathic normal pressure hydrocephalus, was found in venous timing, but it tended to decrease with age at injury, suggesting an overlapping mechanism with normal ageing. Structural bias due to, or a direct causative role of ventriculomegaly was unlikely to play a dominant role, because of the low correlation between venous timing and ventricular size after adjustment for age in both patients and controls. Since post-traumatic hydrocephalus can be asymptomatic and occasionally overlooked, the observation suggested a link between venous drainage and CSF accumulation. Thus, hydrocephalus, involving venous insufficiency, may be a part of normal ageing, can be detected non-invasively, and is potentially treatable. Further investigation into the clinical application of this new marker of venous function is therefore warranted.

Three-dimensional computed tomography analysis of the left gastric vein in a pancreatectomy

BACKGROUND

During a pancreatectomy, the left gastric vein (LGV) has an important role in the venous drainage of the stomach (total pancreatectomy, left splenopancreatectomy, pancreatoduodenectomy with venous resection and pylorus-preserving pancreaticoduodenectomy). Pre-operative knowledge of the LGV's termination is necessary for adequate protection of this vein during dissection. The objective of the present study was to analyse the location of the LGV's termination in a patient population and facilitate its identification in at-risk situations.

MATERIALS AND METHODS

Abdominal computed tomography (CT) images of 86 pancreatic tumour patients (20 of whom underwent surgery), who were treated in our institution between October 2009 and October 2010, were reviewed. Arterial-phase and portal-phase helical CT with three-dimensional reconstruction was performed in all cases. The location of the termination of the LGV was determined and (when the LGV merged with the splenic vein or the splenomesenteric trunk) the distance between the termination and the origin of the portal vein (PV). The correlation between CT imaging data and intra-operative findings was studied.

RESULTS

The LGV was identified on all CT images. In 65% of cases (n= 56), the LGV terminated in the PV (upstream of the liver in nine of these cases). The LGV terminated at the splenomesenteric trunk in 4.7% of cases (n= 4) and in the splenic vein in 30.3% of cases (n= 26). When the LGV terminated upstream of the origin of the PV, the distance between the two was always greater than 1 cm. The average distance between the termination of the LGV and the origin of the PV was 14.34 mm (10.2 to 21.1). The anatomical data from CT images agreed with the intra-operative findings in all cases.

CONCLUSION

Pre-operative analysis of the LGV is useful because the vein can be identified in all cases. Knowledge of the termination's anatomic location enables the subsequent resection to be initiated in a low-risk area.

The complicated role of venous drainage on the survival of arterialized venous flaps

The arterialized venous flap (AVF) has been gradually popularized in clinical settings; however, its survival is still inconsistent and the role of venous drainage remains elusive. In this study, we aimed to investigate the role of venous drainage on the flap survival of arterialized venous flaps. An arterialized venous flap was outlined symmetrically in the rabbit abdomen. The arterial perfusion flap with a unilateral vascular pedicle was taken as the control group and three other experimental groups (I, II and III) were designed based on the number of drainage veins (n = 1, 2 and 3 in the three groups, respectively). Compared with the control group, significant venous congestion was noted in all the experimental groups and the most severe one was seen in group I; while no statistical difference was observed between groups II and III. Similar results regarding blood perfusion state, epidermal metabolite levels and flap survival status were obtained among the three groups. These findings suggested that venous drainage is vital in the survival of the flap, but unlike in the arterial perfusion flaps, the problem of venous congestion can only be partially solved by increasing the number of draining veins. Further studies are warranted to gain insight into this complicated issue.

The venous anatomy of the abdominal wall for Deep Inferior Epigastric Artery (DIEP) flaps in breast reconstruction

BACKGROUND

Despite improving outcomes, venous problems in the harvest of deep inferior epigastric artery perforator (DIEP) flaps remain the more common vascular complications. However, it is apparent that the venous anatomy of the anterior abdominal wall has not been described to the same extent as the arterial anatomy. Cadaveric dissection studies of venous anatomy frequently lack the detail of their arterial counterparts. Venous valves complicate retrograde injection, resulting in poor quality studies with limited anatomical information.

METHODS

The current manuscript comprises a review of the literature, highlighting key features of the anatomy of the venous drainage of the abdominal wall integument, with particular pertinence to DIEP flaps. Both cadaveric and clinical studies are included in this review. Our own cadaveric and in-vivo studies were undertaken and included in detail in this manuscript, with the cadaveric component utilizing direct catheter venography and the in-vivo studies were undertaken using preoperative computed tomographic angiography (CTA), mapping in-vivo venous flow.

RESULTS

Several key features of the venous anatomy of the abdominal wall render it different to other regions, and are of particular importance to DIEP flap transfer.

CONCLUSIONS

The cause of venous compromise is multi-factorial, with perforator diameter, midline crossover, and deep-superficial venous communications all important. Venous cadaveric studies as well as clinical CTA preoperatively can identify these anomalies.

Angiographic predictors of spontaneous obliteration of transarterial partially embolized brain arteriovenous malformations

BACKGROUND

Spontaneous obliteration of cerebral arteriovenous malformations is uncommon but could occur after partial embolization.

METHODS

A retrospective study of 140 patients that underwent embolization for cerebral AVMs from 2005 to August 2019 using liquid embolic agents. The angiographic outcome of patients was classified as regard complete embolization, partial embolization, and complete obliteration after partial embolization. The parameters studied included size, location, number of arterial feeders, number of draining veins, rupture status, embolic agent, and patient factors as well.

RESULTS

The study patients included 74 (53%) females and 66 (47%) males. Their age ranged from 7 to 43 years old. One hundred and eight patients (77%) presented with hemorrhage. The AVM grades were grade II in 57 (40.7%) patients and grade III in 56 (39.3%) patients. Sixty-one (43.57%) patients were treated by n-Butyl Cyanoacrylate and 71 (50.71%) patients were treated with Onyx, and both materials were used together in 8 cases. Follow-up angiography was done from 6 to 36 months after embolization. The rate of complete occlusion in all patients was 61.43% (86 patients). There were three groups of patients, the first group had complete occlusion of the nidus at the time of embolization and included 68 (48.57%) patients. The second group had partial embolization with partial occlusion of the nidus 54 patients (38.57%). The 3rd group included 18 patients (12.85%) with complete nidal occlusion on follow up after partial embolization. The delay in the venous drainage of the AVM to the late arterial phase or early venous phase with flow stasis was a significant predictor of future obliteration on follow up after partial embolization. Other significant parameters that were associated with the progressive disappearance of the AVM nidus on follow up after partial embolization are presentation with hemorrhage, AVMs size less than 3 cm, the presence of single draining or double draining veins, superficial venous drainage, and one or 2 arterial feeders.

CONCLUSION

Spontaneous closure of intracranial arteriovenous malformations after partial embolization may be encountered in cases of stasis of flow during embolization procedure with a delay of the venous drainage. A long-term follow-up of more cases over many years is required to confirm the validity of this conclusion.

Serial stab incision venous drainage technique for simple artery-only fingertip replantation

PURPOSE

Fingertip replantation is a challenging and technically demanding procedure. A variety of venous drainage techniques have been attempted for successful fingertip replantation. We present a new venous drainage technique, known as serial multifocal incision for fingertip replantation.

METHODS

Between 2006 and 2014, we performed 94 fingertip replantations without vein anastomosis. Eighty of the patients were male, and 14 were female, with an overall mean age of 42 years (range: 8-67 years). All patients suffered amputations distal to the distal phalanx joint (Ishikawa subzone I, II, or III). We performed only artery anastomosis. To relieve venous congestion, we incised the fingertip 2-3 mm using a number 11 scalpel blade and allowed the vein to drain naturally. We made small serial incisions every 2-3 days for 1 week.

RESULTS

The overall success rate for this procedure was 90%, with 85 surviving digits. Two patients with partial necrosis and nine patients with complete loss needed a second operation. Two patients received blood transfusions with an average of 1.5 units, but both had an accompanying injury at another site. No one complained of nail deformity or wound infection.

CONCLUSIONS

Various external bleeding techniques have been reported to yield good results. The serial stab incision venous drainage technique is a modified fish-mouth external bleeding technique that overcomes the disadvantages of published methods. This technique is simple, allows for easy control of venous drainage, and reduces the need for blood transfusions compared to other venous drainage techniques that cause large amounts of bleeding. We propose a new method, the serial stab incision venous drainage technique, which is effective and associated with high rates of survival.

Exploring ventricular dysfunction and poor venous drainage during robotic mitral valve surgery

BACKGROUND

del Nido (DN) cardioplegia is commonly used during robotic mitral valve surgery. Poor venous drainage during surgery may result in venous backpressure and washout of this one-shot cardioplegia, limiting its cardioprotective effects.

METHODS

One hundred eighty-seven patients undergoing isolated robotic mitral valve surgery, from January 2015 to July 2017, were retrospectively reviewed. Intraoperative central venous pressure (CVP) tracings were reviewed and venous drainage was categorized as good or poor and the relationship of the quality of venous drainage to postoperative ventricular dysfunction (operationalized as the need for inotropic support during and after weaning from cardiopulmonary bypass [CPB]) was assessed.

RESULTS

Drainage was judged to be good in 107 patients and poor in 79 patients. On univariate analysis, 23 patients (41%) with good drainage required inotropic support whereas 33 patients (59%) with poor drainage required inotropic support (P = .0025). On multivariable analysis, poor venous drainage remained significantly associated with inotropic use even after adjusting for cross-clamp and CPB time. Inotrope use was associated with significantly longer intensive care unit length of stay (P = .027).

CONCLUSION

Maintenance of excellent venous drainage, as assessed by CVP monitoring, should be a high priority in isolated robotic mitral valve surgery undertaken with DN cardioplegia.

New approach to an overlooked flap: Technique to augment venous drainage of the infrahyoid myocutaneous flap

BACKGROUND

To describe a technique in which the anterior jugular vein is preserved in the infrahyoid myocutaneous flap (IHMCF) to augment skin paddle venous drainage.

METHODS

From April 2018 to December 2019, 14 patients with primary oral cancer underwent radical resection and IHMCF reconstruction. Three-dimensional reconstruction of the anterior jugular vein was used to assess the venous drainage of the skin paddle preoperatively. The anterior jugular vein was preserved during dissection of the flap. Healing of the recipient and donor sites was observed.

RESULTS

Total flap necrosis occurred in one patient and marginal skin paddle necrosis occurred in one patient. No flap complications occurred in the other 12 patients.

CONCLUSION

This new approach to augment venous drainage of the IHMCF appears to be effective for decreasing risk of flap necrosis.

Comparison of three infant venous reservoirs with vacuum-assisted venous drainage during varying levels of cardiotomy suction

BACKGROUND

Vacuum-assisted venous drainage has gained widespread use within the pediatric perfusion community for use during cardiopulmonary bypass. It is questioned whether its efficiency may be compromised with application of excessive cardiotomy suction to the infant hard-shell venous reservoir. An in vitro simulation circuit was used to research this phenomenon. A comparison of three different infant hard-shell venous reservoirs also took place to determine if one reservoir type was more advantageous when handling cardiotomy suction. The reservoirs tested were the Maquet VHK 11000, Medtronic Affinity Pixie, and Terumo Capiox FX05.

METHODS

The in vitro simulation circuit consisted of a 1 L reservoir bag that was cannulated at one access point with an Edwards Lifesciences 10Fr aortic cannula and the other access area with an Edwards Lifesciences 10Fr right angle venous cannula and 12Fr right angle venous cannula that were joined together. Key points of measurement and response variables were the pressures on the connection of the venous cannulas, inlet of the venous reservoir, and flow through the venous line. Vacuum was applied and manipulated with a Maquet VAVD Controller to settings of -20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg, and -60 mmHg. Cardiotomy suction was added at settings of 1 LPM, 2 LPM, 3 LPM, and 4 LPM. Values from each response variable were monitored and recorded. These data were utilized to compare the reservoirs with a random coefficient model for each response variable.

CONCLUSIONS

There is an adverse effect of excessive cardiotomy suction on the efficacy of vacuum-assisted venous drainage in infant hard-shell venous reservoirs. There is no significant difference between the VHK 11000, Pixie, and FX05 regarding their ability to handle this occurrence. An important discovery was that the FX05 showed a greater transfer of vacuum to the venous cannulas and reservoir inlet.

Persistent Left Superior Vena Cava with Absent Right Superior Vena Cava

Persistent left superior vena cava (PLSVC) is the most common congenital abnormality of the thoracic systemic venous drainage; in fact, cardiology fellows in training are often quizzed on this when a dilated coronary sinus is noted on an echocardiogram. However, its association with an absent right superior vena cava (RSVC) and how to diagnose this combined condition is less commonly known. We present two cases of PLSVC with an absent RSVC, describe how to recognize and confirm this diagnosis, and discuss its clinical relevance.

Anatomy of the dura mater venous sinus of Alouatta belzebul

The anatomy of the dura mater's venous sinuses is important in the veterinary clinical and surgical area, for cranial procedures and interventions of wild animals, in addition to assisting in the management of neurological diseases, which can prevent serious complications. The macroscopic anatomy of the venous sinuses of the dura mater of Alouatta belzebul was studied. Five adult specimens, males and females, were dissected and fixed in 10% formaldehyde solution. In the dura mater of the Alouatta belzebul, nine venous sinuses were observed, being them dorsal sagittal sinus, ventral sagittal sinus, transverse sinus, straight sinus, sigmoid sinus, temporal sinus, parietal sinus, basilar sinus and cavernous sinus, with morphological similarities in origin, path and destination of blood flow to the internal jugular vein, assisting in the venous drainage function of the brain in this species. These data are similar to those found in other species of non-human and human primates such as Saimiri sciureus, Sapajus libidinosus and Homo sapiens. Of the venous sinuses observed, the cavernous sinus was of considerable clinical and surgical importance in Alouatta belzebul due to its topographic arrangement next to the internal carotid artery and pituitary gland, data that corroborate Sapajus libidinosus, Macaca fascicularis, Macaca mulatta, Papio ursinus, Cercopithecus pygerithrus and Galago senegalensis. In this context, the knowledge of the macroscopic anatomy of the venous sinuses of the dura mater may contribute to the role of veterinarians in less invasive surgical procedures in non-human primates such as Alouatta belzebul and other mammals.

A Hepatectomy Based on a Hybrid Concept of Portal Perfusion of Anterior Segment and Venous Drainage Area of Superior Right Hepatic Vein

BACKGROUND

Right hepatic vein sometimes could not be a reliable landmark between the anterior and posterior segment. The aim of this study was to clarify the portal perfusion area of the anterior segment and to propose a less invasive hepatectomy based on both the portal perfusion and the hepatic venous drainage.

METHODS

Three-dimensional computerized tomography images of 66 patients were constructed. A case, in which the perfusion area of the anterior segment crossed over superior right hepatic vein (SRHV), was called as SRHV-inclusion. It was defined as inclusion of more than 1 cm of the proximal site of SRHV surrounded by the portal perfusion area of the anterior segment.

RESULTS

SRHV-inclusion was observed in 26%. The cases with large inferior right hepatic vein (IRHV) had more frequent SRHV-inclusion (47%). The elderly patient with hepatic disorder, who had hepatocellular carcinoma near the root of the SRHV, underwent a less invasive hepatectomy (anterior segment + SRHV drainage area) resulting in the preservation of the IRHV.

CONCLUSIONS

The perfusion area of the anterior segment crossed over SRHV in one fourth of patients in the study. Our proposed less invasive hepatectomy based on a hybrid concept might be an alternative operative procedure other than right hepatectomy.

Mammary blood flow and venous drainage in cows

The mammary blood flow and the udder drainage in vivo evaluated using the antipyrine absorption method has been compared with the anatomical findings in the udder after slaughtering of the experimental cows (Table 1).

Because of the orientation of the valves in the perineal veins and blood samples taken in vivo it must be assumed that the perineal veins lead blood toward the veins at the udder base.

It is concluded that the drainage of the udder in standing cows will primarily be through the milk veins, eventually there will be a flow of non-mammary venous blood down the external pudic veins at the udder base, as in the case of the perineal veins.

A single-center experience with luminal venous cannulae obstruction caused by clot formation during bypass

Our institution experienced two bypass cases from January through December 2011 in which venous return was significantly variable and at times poor. Luminal clot formation in the venous cannulae was found in each case postbypass. These events were captured and monitored through our institution's Non-Routine Event Reporting Program and eventually reported to the Food and Drug Administration (FDA). We began inspecting all venous cannulae postbypass in December 2011. During a subsequent 9-month surveillance period, we documented 33 venous cannulae in 21 patients with luminal clot formation. Only one cannula during this surveillance period required change-out on bypass. The manufacturer eventually identified changes in production that likely caused the clotting events. The manufacturer modified their production methods and began supplying cannulae produced under the new method in September 2012. We have experienced only one clotting event with the new cannulae and in that instance, the metal tip was found to be defective. We recommend inspection of all venous cannulae postbypass with internal, manufacturer, and FDA reporting for those noted to have luminal clot formation.

The Importance of Intratumoral Venous Drainage Preservation in Two-Stage Surgery of Large Hypervascular Choroid Plexus Papilloma: A Case Report

Two-stage surgery may be necessary when total tumor removal cannot be accomplished in the first surgery; however, the extent and condition in which the remaining tumor should be before the next surgery have not yet been established. There is a risk of postoperative hemorrhage in the residual tumor, especially in hypervascular tumors. We report a case of hypervascular choroid plexus papilloma (CPP) in a 22-year-old male patient where the preservation of intratumoral venous drainage was considered important to avoid hemorrhagic complications during a two-stage surgery. In the first surgery, it was difficult to control the bleeding from the debulked tumor, and the surgery was terminated due to severe blood loss. Large draining veins running in the tumor were preserved as it was suspected that these were important drainage routes of the bloodstream of the tumor. The preserved draining red veins changed to normal venous color in the second surgery performed after one week. The residual tumor was not vascularized during the second surgery and underwent gross total resection with less blood loss. The patient was discharged without sequelae. There was no recurrence of the tumor and no neurological deficit during the three-year follow-up. To prevent postoperative hemorrhage associated with a residual tumor, it may be important to preserve venous drainage of the tumor in hypervascular tumor resection.

Is there an Influence of Match and Mismatch of Venous Drainage Pattern on AVM Hemorrhagic Presentation?

Objective

To analyze whether there is an influence of match and mismatch of venous drainage patterns on arteriovenous malformation (AVM) hemorrhagic presentation.

Methods

Consecutive 161 patients of AVM between 2014 and 2017 were retrospectively reviewed. Venous drainage was considered deep or superficial. Match of venous drainage pattern was defined as a superficial AVM with only superficial venous drainage or a deep AVM with deep venous drainage. Mismatch of venous drainage pattern was defined as a superficial AVM involving a deep venous drainage. Univariate analysis was used to assess the influence of match and mismatch of venous drainage pattern on AVM hemorrhagic presentation.

Results

AVM location and venous drainage were matched in 116 patients, including superficial location with superficial venous drainage or deep location with deep venous drainage, and were mismatched in 45 patients, including superficial location with deep venous drainage. The rupture proportion of mismatch venous drainage pattern was statistically comparable to that of deep location with deep drainage (P = 0.819). However, superficial location with deep venous drainage was statistically associated with a higher rupture percentage than that of superficial location with superficial venous drainage (P = 0.003).

Conclusions

Mismatch venous drainage pattern or an exclusively deep venous drainage is associated with an initial clinical presentation with an AVM hemorrhage.

Effects of arterial blood supply on the survival of reverse-flow island flaps: an experimental study

OBJECTIVES

This study aimed to investigate the effect of arterial blood supply on the survival area of retrograde island flap.

METHODS

The vein and saphenous artery in rabbits were selected to design the reverse-flow island flap experimental model. Forty rabbits were randomly divided into four groups: control group (group A), partial anastomosis of the saphenous artery group (group B), partial anastomosis of the vein group (group C), and no superficial vein group (group D). Flap survival was observed postoperatively, the survival area was measured, and the survival rate was compared. Blood distribution in the flap at different time points was observed by radionuclide imaging.

RESULTS

The blood vessel distribution and blood cell status were observed histologically. The survival rate of flaps in group B was higher than that of the other three groups (P < 0.05). The radioactive material (RM) could be seen clearly in group B, whereas those in groups A, C, and D existed transiently. The RM in group B was higher than that in groups A, C, and D (P < 0.05). On postoperative day 10, group B had more capillary regeneration and blood cells than the other three groups (P < 0.05).

CONCLUSIONS

Increasing blood supply can improve the survival rate of flaps, but simply promoting venous return has no significant effect on the survival rate of flaps.

Spontaneous and uneventful anal expulsion of expanded polytetrafluoroethylene (e-PTFE) vascular graft after living donor liver transplantation

Living donor liver transplantation (LDLT) is a useful therapeutic option for end-stage liver disease due to the shortage of deceased donor liver grafts, particularly in Asia and Türkiye. Right liver LDLT is frequently performed in adults and some cases require anterior section venous drainage. Synthetic grafts, particularly expanded polytetrafluoroethylene (e-PTFE), are often preferred for venoplasties. Despite its many advantages, some complications associated with these grafts have been reported, such as gastrointestinal tract migration, perforation, and bleeding. Here we present an extremely rare case about an e-PTFE graft.

[Relationship between the features of venous drainage of supratentorial arteriovenous malformations and the risk of intracranial hemorrhage]

BACKGROUND

Intracranial hemorrhage is the most common complication of cerebral arteriovenous malformations (AVM). In recent years, most studies devoted to the features of AVM functioning consider venous drainage as important factor influencing the rupture of malformation.

OBJECTIVE

To review the literature data on the relationship between the features of venous drainage of cerebral arteriovenous malformations and intracranial hemorrhage.

MATERIAL AND METHODS

We found 43 studies discussing the features of AVM venous drainage for the period from 1982 to 2020. Most of reports were published between 2005 and 2020.

RESULTS

Deep venous drainage and a single drainage vein were the most significant factors influencing the risk of hemorrhage. Venous ectasia, reflux, stenosis, number, length and tortuosity of drainage veins were less important for the risk of AVM rupture.

CONCLUSION

Analysis of the features of AVM venous drainage can make it possible to predict the natural course of disease and risk of intracranial hemorrhage. These aspects are essential for neurosurgical treatment.

Vortex vein engorgement and different shapes of venous drainage systems in polypoid choroidal vasculopathy vs. age‑related macular degeneration on indocyanine green angiography

There are differences in vortex vein engorgement and appearance in polypoid choroidal vasculopathy (PCV), age-related macular degeneration (AMD), and healthy eyes. The present study aimed to use indocyanine green angiography (ICGA) to find a simple, clinically meaningful method for evaluating the filling degree of vortex veins in various eye diseases. Participant clinical characteristics were recorded. The number of vortex veins (NVV), central vortex vein diameter (CVVD), mean root area of the vortex vein (MRAVV), mean diameter of the thickest peripheral branch (MDPTB), subfoveal choroidal thickness and percentage of vortex vein anastomosis (PVVA) were obtained by marking the vortex veins on ICGA. The proportion of subretinal haemorrhage and the numbers and types of vortex veins in each quadrant were counted separately. The CVVD and MDPTB were significantly increased in the PCV compared with those in the AMD group (P<0.05). The CVVD, MRAV, and PVVA were significantly increased in the PCV compared with those in the healthy group (P<0.05). The type IV vortex vein (complete with ampulla) proportion was the lowest while the type I (vortex vein absent) proportion was the highest in the PCV group (P<0.001). NVV in the inferior-temporal region was increased in the PCV compared with that in the AMD group (P=0.034). Subretinal haemorrhage occurred in the inferior temporal choroid in 47.62% of examined eyes in PCV group, and in the superior temporal choroid in 23.81% of the PCV group, with significant differences between the quadrants (P<0.001). Vortex vein engorgement and shape differed significantly between PCV, AMD and healthy eyes. The vortex vein branches in PCV eyes were significantly dilated in the posterior pole; moreover, the peripheral choroid and the lower proportion of type IV vortex veins may be pathognomonic for PCV.

Variations of venous drainage of the thyroid gland and their surgical implications: a narrative review

Diseases of the thyroid are common worldwide, so knowledge of its normal and variant anatomy, especially of the veins of thyroid, is essential for safe and successful surgery involving the anterolateral neck. The aim of this study is to consolidate all information related to venous drainage of the thyroid gland as a ready reference for vascular and endocrine surgeons. The study was conducted at the Department of Anatomy and the literature search was carried out using the Pubmed, Scielo, Researchgate, Medline, and Scopus databases. Various terms related to the thyroid gland and its venous drainage were used to explore the literature. The literature review revealed that the superior and middle thyroid veins have the fewest variations in terms of course and termination while the inferior thyroid vein has the most variations in terms of course and termination. Detailed knowledge of normal and variant anatomy of the thyroid veins is of utmost use for vascular surgeons performing anterolateral neck surgery, especially tracheostomy, a lifesaving procedure, minimizing intraoperative and postoperative complications and morbidity and mortality.

Acute Dilation of Venous Sinuses in Animal Models of Mild Traumatic Brain Injury Detected Using 9.4T MRI

Mild traumatic brain injury (mTBI) is a debilitating but extremely common form of brain injury that affects a substantial number of people each year. mTBI is especially common in children and adolescents. Our understanding of mTBI pathophysiology is limited, and there is currently no accepted marker for disease severity. A potential marker for disease severity may be cerebrovascular dysfunction. Recent findings have implicated cerebrovascular alteration as an important component of mTBI and suggest it contributes to the development of persistent, long-term symptoms. In this paper, we conducted two studies to investigate whether mTBI affects venous drainage patterns in the central nervous system using alterations in the size of venous sinuses as a marker of changes in drainage. Using a closed head vertical weight-drop model and a lateral impact injury model of mTBI, we imaged and quantified the size of three major draining vessels in the adolescent rat brain using 9.4T MRI. Areas and volumes were quantified in the superior sagittal sinus and left and right transverse sinuses using images acquired from T2w MRI in one study and post-gadolinium T1w MRI in another. Our results indicated that the three venous sinuses were significantly larger in mTBI rats as compared to sham rats 1-day post injury but recovered to normal size 2 weeks after. Acutely enlarged sinuses post-mTBI may indicate abnormal venous drainage, and this could be suggestive of a cerebrovascular response to trauma.