Transcriptional Control of Lipid Metabolism.

Transcriptional control of lipid metabolism uses a framework that parallels the control of lipid metabolism at the protein or enzyme level, via feedback and feed-forward mechanisms. Increasing the substrates for an enzyme often increases enzyme gene expression, for example. A paucity of product can likewise potentiate transcription or stability of the mRNA encoding the enzyme or enzymes needed to produce it. In addition, changes in second messengers or cellular energy charge can act as on/off switches for transcriptional regulators to control transcript (and protein) abundance. Insects use a wide range of DNA-binding transcription factors (TFs) that sense changes in the cell and its environment to produce the appropriate change in transcription at gene promoters. These TFs work together with histones, spliceosomes, and additional RNA processing factors to ultimately regulate lipid metabolism. In this chapter, we will first focus on the important TFs that control lipid metabolism in insects. Next, we will describe non-TF regulators of insect lipid metabolism such as enzymes that modify acetylation and methylation status, transcriptional coactivators, splicing factors, and microRNAs. To conclude, we consider future goals for studying the mechanisms underlying the control of lipid metabolism in insects.

Exploring heart dissection techniques for enhancing anatomical education: a pilot study to replicate transthoracic echocardiography.

PURPOSE: For novice learners, converting two-dimensional (2D) images of echocardiography to three-dimensional (3D) cardiac structures is deemed challenging. This study aimed to develop an accurate dissection method of the heart to reproduce the transthoracic echocardiographic views on cadavers and elucidate new educational methods in human anatomy dissection courses. METHODS: A total of 18 hearts were used in this study. After reflecting the anterior thoracic wall inferiorly, the hearts were excised from embalmed cadavers. Thereafter, three landmarks were set on the heart for each plane of the incision, and the hearts were incised to observe the three different echocardiographic views, which include the apical four-chamber view (A4C), parasternal long axis (PLAX) view, and parasternal short axis (PSAX) view at the papillary muscle level. If all structures for observation during routine echocardiography are clearly observed in each view, a successful incision is considered. All procedures and incisions were performed by the medical students. After a successful incision, hearts were returned to the original position in the pericardial sac for further observation. RESULTS: The success rates of incision for each view were 83.3% (5/6 success cases), 83.3% (5/6 success cases), and 66.7% (4/6 success cases) in the A4C view, PLAX view, and PSAX view at the papillary muscle level, respectively. CONCLUSION: This dissection method could probably be employed to reproduce transthoracic echocardiographic views on cadaveric hearts, which is beneficial for novice learners for a deeper understanding of the anatomy.

Symptomatic Dermal Inclusion Cysts in Infants following Fetal Surgery for Myelomeningocele: Report of Two Cases and Review of the Literature.

INTRODUCTION: It remains unclear if fetal repair of myelomeningocele (MM) is associated with a greater risk of developing symptomatic dermal inclusion cysts (ICs) at the neural placode. We report two infants treated with fetal surgery who developed symptomatic IC at less than 1 year of age, and we discuss the current literature on symptomatic IC in children with MM. CASE PRESENTATION: Two infants underwent fetal MM repair at 24 weeks of gestational age. Case 1 was born at 30 weeks and had two revisions of the MM wound early in life. At 8 months of age, the patient presented with meningismus and imaging findings of an IC, which was resected at the time of presentation. At 3 years of age, this patient was found to have recurrence of the IC after presenting with worsening bladder function and underwent repeat debulking with no recurrence at 6 years of age. Case 2 was born at 32 weeks of gestational age with uncomplicated recovery. At 8 months of age, the patient presented with irritability and fullness at the lumbar repair site. Imaging showed a large IC with restricted diffusion and extension into the subcutaneous tissue; this was resected completely at the time of presentation, see intraoperative photographs. There has been no sign of recurrence at age of 15 months. CONCLUSIONS: Careful monitoring for IC in infancy in MM patients who have had fetal surgery is recommended.

Early Experience With New Generation Deep Brain Stimulation Leads in Parkinson's Disease and Essential Tremor Patients.

BACKGROUND: Newer generation deep brain stimulation (DBS) systems have recently become available in the United States. Data on real-life experience are limited. We present our initial experience incorporating newer generation DBS with Parkinson's disease (PD) and essential tremor (ET) patients. Newer systems allow for smart energy delivery and more intuitive programming and hardware modifications including constant current and directional segmented contacts. METHODS: We compared six-month outcomes between 42 newer generation and legacy leads implanted in 28 patients. Two cohorts each included 7 PD patients with bilateral subthalamic nucleus (STN) stimulation and 7 ET patients with unilateral ventral intermediate nucleus (VIM) stimulation of the thalamus. All directional leads included 6172 Infinity 8-Channel Directional leads and Infinity internal pulse generators (Abbott Neuromodulation, Plano, TX, USA) and nondirectional leads included lead 3389 with Activa SC for VIM and PC for STN (Medtronic, Minneapolis, MN, USA). RESULTS: Six-month outcomes for medication reduction and motor score improvements between new and legacy DBS systems in PD and ET patients were similar. Directionality was employed in 1/3 of patients. Therapeutic window (difference between amplitude when initial symptom relief was obtained and when intolerable side effects appeared with the contact being used) was significantly greater in new DBS systems in both PD (p = 0.005) and ET (p = 0.035) patients. The windows for new and legacy systems were 3.60 V ± 0.42 and 2.00 V ± 0.32 for STN and 3.06 V ± 0.44 and 1.85 V ± 0.28 for VIM, respectively. DISCUSSION: The therapeutic window of newer systems, whether or not directionality was used, was significantly greater than that of the legacy system, which suggests increased benefit and programming options. Improvements in hardware and programming interfaces in the newer systems may also contribute to wider therapeutic windows. We expect that as we alter workflow associated with newer technology, more patients will use directionality, and amplitudes will become lower.

Implications of Multiple Complications on the Postoperative Recovery of General Surgery Patients.

OBJECTIVES: To evaluate the association between multiple complications and postoperative outcomes and to assess which complications occur together in patients with multiple complications. BACKGROUND: Patients who suffer multiple complications have increased risk of prolonged hospital stay and mortality. However, little is known about what places patients at risk for multiple complications or which complications tend to occur in these patients. METHODS: Surgical patients were identified from the American College of Surgeons National Quality Improvement Program (ACS NSQIP) database from 2005 to 2011. The frequency of postoperative complications was assessed. Patients with less than two complications were compared with patients who had multiple complications using χ and logistic regression analysis. Relationships among postoperative complications were explored by learning a Bayesian network model. RESULTS: The study population consisted of 470,108 general surgery patients. The overall complication rate was 15% with multiple complications in 27,032 (6%) patients. Patients with multiple complications had worse postoperative outcomes (P < 0.001). The strongest predictors for developing multiple complications were admission from chronic care facility or nursing home, dependent functional status, and higher American Society of Anesthesiologist Physical Status classification. In patients with multiple complications, the most common complication was sepsis (42%), followed by failure to wean ventilator (31%), and organ space surgical site infection (27%). We found that severe complications were most strongly associated with development of multiple complications. Using a Bayesian network, we were able to identify how strongly associated specific complications were in patients who developed multiple complications. CONCLUSIONS: Almost half (40%) of patients with complications suffer multiple complications. Patient factors such as frailty and comorbidity strongly predict the development of multiple complications. The results of our Bayesian analysis identify targets for interventions aimed at disrupting the cascade of multiple complications in high-risk patients.

The regulation of carnitine palmitoyltransferase 1 (CPT1) mRNA splicing by nutrient availability in Drosophila fat tissue.

After a meal, excess nutrients are stored within adipose tissue as triglycerides in lipid droplets. Previous genome-wide RNAi screens in Drosophila cells have identified mRNA splicing factors as being important for lipid droplet formation. Our lab has previously shown that a class of mRNA splicing factors called serine/arginine-rich (SR) proteins, which help to identify intron/exon borders, are important for triglyceride storage in Drosophila fat tissue, partially by regulating the splicing of the gene for carnitine palmitoyltransferase 1 (CPT1), an enzyme important for mitochondrial ß-oxidation of fatty acids. The CPT1 gene in Drosophila generates two major isoforms, with transcripts that include exon 6A producing more active enzymes than ones made from transcripts containing exon 6B; however, whether nutrient availability regulates CPT1 splicing in fly fat tissue is not known. During ad libitum feeding, control flies produce more CPT1 transcripts containing exon 6B while fasting for 24 h results in a shift in CPT1 splicing to generate more transcripts containing exon 6A. The SR protein 9G8 is necessary for regulating nutrient responsive CPT1 splicing as decreasing 9G8 levels in fly fat tissue blocks the accumulation of CPT1 transcripts including exon 6A during starvation. Protein kinase A (PKA), a mediator of starvation-induced lipid breakdown, also regulates CPT1 splicing during starvation as transcripts including exon 6A did not accumulate when PKA was inhibited during starvation. Together, these results indicate that CPT1 splicing in adipose tissue responds to changes in nutrient availability contributing to the overall control of lipid homeostasis.

Endoscopic Endonasal Approach to the Orbit: A Case Series and Clinical Experience Emphasizing the Advantages of the Ipsilateral Mononostril Technique.

BACKGROUND: Lesions situated within the orbit pose significant challenges in management due to the confined space they occupy and their proximity to critical anatomical structures. The objective of our study is to assess the feasibility of the ipsilateral endoscopic endonasal approach for orbital cavernous hemangiomas and to comprehend the surgical anatomy of the orbital apex and inferomedial orbital structures. METHODS: Thirteen patients (8 women, 5 men), with ages ranging from 25 to 54 years (mean 35.2 ± 8.3 years), with orbital cavernous hemangioma who underwent surgery via the ipsilateral mononostril endoscopic endonasal approach between August 2018 and August 2023 were retrospectively evaluated. Demographic characteristics, clinical data, radiographic images, and clinical outcomes of the patients were collected from digital medical records. RESULTS: The left orbit was more commonly affected (9 left, 4 right). The average postoperative follow-up duration was 22.2 months (range: 6-50 months). Among the 13 cases of orbital cavernous hemangioma, 1 (7.7%) was located in the extraconal compartment, and 12 (92.3%) were situated in the intraconal compartment. Complete surgical resection of the tumor was successfully achieved in all patients. CONCLUSIONS: Our study highlights the potential advantages of employing a purely ipsilateral mononostril endoscopic endonasal approach for orbital surgery, particularly for accessing the orbital apex and managing medial and inferomedial orbital lesions. This technique holds promise for reducing morbidity and enhancing outcomes, especially when combined with careful patient selection, preoperative planning, and advanced endoscopic skills.

Robot-assisted T12 pediculectomy and resection of a ventral thoracic meningioma.

Spinal meningiomas represent 25%-45% of intradural spinal tumors and are commonly seen in the thoracic spine. Ventral midline spinal meningiomas in the thoracic spine are challenging lesions to resect given their location in relation to the spinal cord. Resection for symptomatic or growing lesions requires adequate bone removal to limit retraction of the spinal cord. Surgical adjuncts such as intraoperative navigation, robotics, and ultrasound can improve the efficiency of and safety for resection of these lesions. The authors present a case of a complete resection of a ventral thoracic meningioma using a T12 transpedicular approach with robot-assisted navigated pediculectomy and intraoperative ultrasonography.

Transcutaneous bilirubin levels in extremely preterm infants less than 30 weeks gestation.

OBJECTIVE: The primary objective of this study was to determine the relationship between transcutaneous bilirubin (TcB) levels and total serum bilirubin (TSB) levels in extremely preterm infants. STUDY DESIGN: We conducted a prospective multicenter study of extremely preterm infants less than 30 weeks gestation in California. Difference between paired TcB and TSB values were compared based on gestational age, birth weight, maternal race/ethnicity, chronological age as well as during and after phototherapy. RESULTS: TSB values ranged from 0 to 12.6 mg/dl and the TcB values ranged from 0 to 14.2 mg/dl. TSB was predicted with a high degree of accuracy at TSB = 2.37 + 0.54 (TcB) with r = 0.786. There was good correlation across gestational age, birth weight, race/ethnic, chronological age subgroups as well as during and after phototherapy. CONCLUSION: Our study supports the use of TcB as a screening tool for monitoring jaundice in extremely preterm infants.

Surgical Limitations of the Microscopic Transciliary Supraorbital Keyhole Approach to the Anterior and Middle Skull Base.

BACKGROUND: The microscopic transciliary SupraOrbital keyhole (mtSO) approach has been used for a wide variety of anterior and middle fossa pathologies, including aneurysms, meningiomas, craniopharyngiomas, and other skull-base tumors. Several clinical series have proven its efficacy and safety, but detailed anatomical demarcations of the anterior and middle cranial base exposure are lacking. Our aim was to define the surgical limitations of the mtSO approach to the ipsilateral and contralateral anterior and middle skull base. METHODS: Five cadaveric specimens (10 sides) were studied with image guidance to illustrate the limits of the surgical exposure. In addition, 30 dry skulls were used to measure the working distances between the craniotomy and key bony landmarks of the mtSO approach. RESULTS: Surgical exposure at the anterior skull base covered the area between the medial half of the contra- and the medial two-thirds of the ipsilateral sphenoid wing including both optic nerves and interoptic space. The anterior limit at the midline was the sphenoethmoidal suture. Ipsilateral anterior clinoidectomy permitted exposure of the superior orbital fissure, which defined the anteromedial limit at the middle fossa, whereas the anterolateral limit was defined by the ophthalmic branch of the trigeminal nerve. Moreover, the posteromedial and posterolateral limits were the posterior clinoid process and the petrous ridge, respectively. CONCLUSIONS: Our findings define the surgical limitations of the mtSO approach for the treatment of anterior and middle cranial base pathologies. These limits can be reliably identified on imaging studies allowing assessment of exposure to guide preoperative case selection.

Anatomical Limits of the Endoscopic Contralateral Transmaxillary Approach to the Petrous Apex and Petroclival Region.

Objectives This study aimed to establish the anatomical landmarks for performing a contralateral transmaxillary approach (CTM) to the petrous apex (PA) and petroclival region (PCR), and to compare CTM with a purely endoscopic endonasal approach (EEA). Design EEA and CTM to the PA and PCR were performed bilaterally in eight human anatomical specimens. Surgical techniques and anatomical landmarks were described, and EEA was compared with CTM with respect to ability to reach the contralateral internal acoustic canal (IAC). Computed tomographic scans of 25 cadaveric heads were analyzed and the "angle" and "reach" of CTM and EEA were measured. Results Entry to the PA via a medial approach was limited by (1) abducens nerve superiorly, (2) internal carotid artery (ICA) laterally, and (3) petroclival synchondrosis inferiorly (Gardner's triangle). With CTM, it was possible to reach the contralateral IAC bilaterally in all specimens dissected, without dissection of the ipsilateral ICAs, pterygopalatine fossae, and Eustachian tubes. Without CTM, reaching the contralateral IAC was possible only if: (1) angled endoscopes and instruments were employed or (2) the pterygopalatine fossa was dissected with mobilization of the ICA and resection of the Eustachian tube. The average "angle" and "reach" advantages for CTM were 25.6-degree greater angle of approach behind the petrous ICA and 1.4-cm more lateral reach. Conclusion The techniques and anatomical landmarks for CTM to the PA and PCR are described. Compared with a purely EEA, the CTM provides significant "angle" and "reach" advantages for the PA and PCR.

The Infratemporal Retro-Eustachian Transposition of the Temporoparietal Fascial Flap for Clival Reconstruction After Endoscopic Endonasal Approach: An Anatomic Conceptual Technique.

BACKGROUND: Reconstruction after endoscopic endonasal approaches is a key element. Lower clivus reconstruction is difficult and most of the times a pedicled flap is not available. As the complexity and the dimensions of the exposure increase, a reliable reconstruction technique becomes more and more important. OBJECTIVE: To describe the anatomic and technical nuances of the transposition of the temporoparietal fascial flap for lower clivus reconstruction. METHODS: A specific temporoparietal fascial flap (TPFF) design and tunneling technique has been studied using 4 head specimens, microscopic and endoscopic surgical techniques, and neuronavigation. RESULTS: The L-shaped flap offers several advantages. It can be tunneled directly toward the lower clivus passing through the infratemporal fossa. CONCLUSION: The infratemporal retro-eustachian transposition of an L-shaped TPFF provides a vascularized tissue virtually without dimension limits. This is the only technique that allows the flap to be tunneled directly in the lower clivus with the most vascular portion being at the bottom of the defect. Clinical validation is still required since more issues may become relevant in a real-surgery setting. Though, due to its possible complications, this methodology needs further testing and should not be attempted in less experienced hands.

Erythropoietin is not a risk factor for severe retinopathy of prematurity among high risk preterm infants.

BACKGROUND: Retinopathy of prematurity (ROP) is a developmental retinal vaso-proliferative disease and a leading cause of blindness in children. Early gestational age, low birth weight and unregulated oxygen exposure are the main risk factors for the development of ROP. There are conflicting reports of a possible association between recombinant Erythropoietin (rhEPO) use and an increased risk for the development of ROP. OBJECTIVE: To determine whether rhEPO is an independent risk factor for the development of severe ROP among preterm infants with a gestational age of 23 to 32 weeks and a birth weight <1500 g. METHODS: We performed a retrospective study of risk factors for ROP on a cohort of 1762 premature infants born between 2009 and 2014, half of whom received rhEPO. To examine the association between treated ROP and rhEPO, a propensity score (PS) analysis was performed using the inverse probability of treatment weighted (IPTW) approach. RESULTS: The incidence of treated ROP was 7.3% (129/1762). PS analysis did not show an association between rhEPO and severe ROP needing treatment or ROP stage 2 or higher, in either the whole population or in the subgroup of babies born at 23 to 28 weeks gestation, in whom the incidence of severe ROP was the highest. Of 117 patients treated for Type 1 or worsening stage 3 ROP, 17 were first diagnosed after NICU discharge. CONCLUSION: Our study showed no association between Erythropoietin use and severe ROP and highlights the importance of Ophthalmology follow up after hospital discharge.

Real-World Anticoagulant Use and Incidence of Venous Thromboembolism and Major Bleeding in Children.

PURPOSE: Children generally have a lower risk of venous thromboembolism (VTE) than adults, but those with acute and chronic conditions requiring hospitalization and surgical procedures are at increased risk. Anticoagulant use in children has not been systematically studied, and limited data exist. This study aimed to provide data on the conditions associated with use of anticoagulants, the type of anticoagulant used in children, and the incidence of thromboembolism and major bleeding events reported in this population. METHODS: To increase understanding of the use of anticoagulant therapies in children with at-risk conditions, 3 health claims databases in the United States were analyzed to describe the characteristics of use of heparins, warfarin, and direct oral anticoagulants (DOACs). Cumulative drug exposure was determined for continuous exposure, defined as >30 days. Unadjusted event rates of VTE and major bleeding after exposure to these therapies were reported. The data were presented descriptively and are not intended for comparison or to imply any causation. FINDINGS: Anticoagulants were infrequently used in the pediatric population, including at any time point after Fontan surgery for congenital heart disease. Heparins were used most frequently in the population overall and especially for patients aged <12 years. DOACs were used least often and primarily for patients ages 12 to <18 years. Among pediatric patients exposed to anticoagulants, unadjusted incidence rates of VTE per 1000 person-years of exposure ranged from 30.8 to 34.0 for all DOACs, 21.6 to 46.2 for warfarin, and 6.0 to 7.3 for heparins. Rates per 1000 person-years for major bleeding ranged from 0 to 4.9 for all DOACs, 4.3 to 6.7 for warfarin, and 3.7 to 4.6 for heparins. IMPLICATIONS: With results from clinical trials evaluating DOACs in the pediatric population expected in the next 2 years, these descriptive real-world data may provide a baseline understanding of current prescribing patterns and outcomes associated with the use of DOACs and other anticoagulants in routine pediatric clinical practice. This information represents the use of real-world evidence and may function as the benchmark for evaluating changes in prescription practices and potential outcomes in the future.

Comparative Risk Assessment of Severe Uterine Bleeding Following Exposure to Direct Oral Anticoagulants: A Network Study Across Four Observational Databases in the USA.

BACKGROUND: Antithrombotic therapies are associated with an increased bleeding risk. Abnormal uterine bleeding data have been reported in clinical trials of patients with venous thromboembolism (VTE), but data are limited for patients with atrial fibrillation (AF). OBJECTIVE: Using real-world data from four US healthcare databases (October 2010 to December 2018), we compared the occurrence of severe uterine bleeding among women newly exposed to rivaroxaban, apixaban, dabigatran, and warfarin stratified by indication. METHODS: To reduce potential confounding, patients in comparative cohorts were matched on propensity scores. Treatment effect estimates were generated using Cox proportional hazard models for each indication, in each database, and only for pairwise comparisons that met a priori study diagnostics. If estimates were homogeneous (I2 < 40%), a meta-analysis across databases was performed and pooled hazard ratios reported. RESULTS: Data from 363,919 women newly exposed to a direct oral anticoagulant or warfarin with a prior diagnosis of AF (60.8%) or VTE (39.2%) were analyzed. Overall incidence of severe uterine bleeding was low in the populations exposed to direct oral anticoagulants, although relatively higher in the younger VTE population vs the AF population (unadjusted incidence rates: 2.8-33.7 vs 1.9-10.0 events/1000 person-years). In the propensity score-matched AF population, a suggestive, moderately increased risk of severe uterine bleeding was observed for rivaroxaban relative to warfarin [hazard ratios and 95% confidence intervals from 0.83 (0.27-2.48) to 2.84 (1.32-6.23) across databases with significant heterogeneity], apixaban [pooled hazard ratio 1.45 (0.91-2.28)], and dabigatran [2.12 (1.01-4.43)], which were sensitive to the time-at-risk period. In the propensity score-matched VTE population, a consistent increased risk of severe uterine bleeding was observed for rivaroxaban relative to warfarin [2.03 (1.19-3.27)] and apixaban [2.25 (1.45-3.41)], which were insensitive to the time-at-risk period. CONCLUSIONS: For women who need antithrombotic therapy, personalized management strategies with careful evaluation of benefits and risks are required. CLINICALTRIALS. GOV REGISTRATION: NCT04394234; registered in May 2020.

Discordance between the Clinical Presentation and Morphology of Myocardial Infarction in a Patient with Acute Post-Hemorrhagic Anemia.

While atherosclerotic plaque disruption remains the hallmark of type 1 myocardial infarction (T1MI), multiple other mechanisms provoking myocardial supply/demand mismatch (eg, anemia and tachyarrhythmias) are recognized as the potential causes of type 2 myocardial infarction (T2MI). In clinical practice, angiography is underutilized in patients with MI that have typical T2MI triggers, although the presence of these triggers and various forms of atherosclerotic coronary artery disease is not mutually exclusive. We describe a 70-year-old man that developed MI during hospitalization for gastrointestinal bleeding. He was treated conservatively without angiography due to posthemorrhagic anemia, which is a recognized T2MI trigger, and subsequently developed refractory cardiogenic shock. Autopsy revealed atherothrombosis, which is characteristic of T1MI.

Spinal Cord Stimulation.

Spinal cord stimulation (SCS) has been well established as a safe and effective treatment of pain derived from a wide variety of etiologies. Careful patient selection including a rigorous trial period and psychological evaluation are essential. When patients proceed to permanent implantation, various considerations should be made, such as the type of lead, type of anesthesia, and waveform patterns for SCS. This article discusses the common indications for SCS, patient selection criteria, and pertinent outcomes from randomized clinical trials related to common indications treated with SCS. Technical considerations, such as type of implant, anesthesia, and programming, are also discussed.

Improving Medication Information Presentation Through Interactive Visualization in Mobile Apps: Human Factors Design.

BACKGROUND: Despite the detailed patient package inserts (PPIs) with prescription drugs that communicate crucial information about safety, there is a critical gap between patient understanding and the knowledge presented. As a result, patients may suffer from adverse events. We propose using human factors design methodologies such as hierarchical task analysis (HTA) and interactive visualization to bridge this gap. We hypothesize that an innovative mobile app employing human factors design with an interactive visualization can deliver PPI information aligned with patients' information processing heuristics. Such an app may help patients gain an improved overall knowledge of medications. OBJECTIVE: The objective of this study was to explore the feasibility of designing an interactive visualization-based mobile app using an HTA approach through a mobile prototype. METHODS: Two pharmacists constructed the HTA for the drug risperidone. Later, the specific requirements of the design were translated using infographics. We transferred the wireframes of the prototype into an interactive user interface. Finally, a usability evaluation of the mobile health app was conducted. RESULTS: A mobile app prototype using HTA and infographics was successfully created. We reiterated the design based on the specific recommendations from the usability evaluations. CONCLUSIONS: Using HTA methodology, we successfully created a mobile prototype for delivering PPI on the drug risperidone to patients. The hierarchical goals and subgoals were translated into a mobile prototype.

Surgical Anatomy of the Subcallosal Artery: Implications for Transcranial and Endoscopic Endonasal Surgery in the Suprachiasmatic Region.

BACKGROUND: Suprachiasmatic subcallosal lesions may have an intimate relationship with the anterior communicating artery (AcomA); injury to AcomA branches can result in basal forebrain infarction and cognitive dysfunction. OBJECTIVE: To evaluate anatomic variations of the AcomA basal perforating branches, especially the subcallosal artery (ScA), for clinical implications when approaching the suprachiasmatic subcallosal region from endonasal and transcranial routes. METHODS: The origin, course, diameter, and branching pattern of the AcomA's perforating branches were studied in 33 specimens from transcranial and endonasal perspectives. RESULTS: The ScA was present in 79% of the specimens as a single dominant artery arising from the posterior/posterosuperior surface of the AcomA, along with hypothalamic arteries (55%), or as a single artery (24%). It coursed posteriorly towards the lamina terminalis region, curving superiorly to the subcallosal area. The ScA gave off many branches to provide the main blood supply to the subcallosal region. Importantly, it supplies the septal/subcallosal region bilaterally. The ScA can be found posterior, superior, or inferior to the AcomA when using a transylvian, interhemispheric, or endonasal approach, respectively. In specimens with no ScA (21%), the median callosal artery (MdCA) was the dominant artery arising from the AcomA. It followed an identical course to the ScA, providing supply to the same structures bilaterally, but its distal extension reached the body/splenium of the corpus callosum. The MdCA is a ScA variant. CONCLUSION: The ScA is a unique vessel because it supplies the septal/subcallosal region bilaterally; preservation of this vessel during surgery is crucial for successful outcomes.

Proximal Branches of the Anterior Cerebral Artery: Anatomic Study and Applications to Endoscopic Endonasal Surgery.

BACKGROUND: The endoscopic endonasal approach is a surgical alternative for midline anterior skull base tumors. A detailed understanding of the proximal anterior cerebral artery (ACA) branches' anatomy from an endonasal perspective is essential for avoiding vascular complications. OBJECTIVE: To evaluate, from an endonasal perspective, the anatomic variations of the ACA and its proximal branches, specifically the recurrent artery of Heubner (RAH), and the fronto-orbital (FOA) and frontopolar (FPA) arteries. METHODS: We study the origin, course, branching pattern, diameter, and relationship between the proximal ACA branches and the optic apparatus and olfactory tract in 25 head specimens. RESULTS: The RAH was present in all hemispheres and originated within 3 ± 1.5 mm of the AcomA, with a 0.4 ± 0.1 mm diameter. Based on its relationship with the A1 segment, we observed three RAH courses: anterior (40%), superior (22%), and posterior (38%). The FOA was present in all cases, a mean of 6 ± 4 mm from the AcomA, with a 0.7 ± 0.4 mm diameter. The FOA arose mainly from the A2 (70%), with three courses in relation to the olfactory tract: crossing its proximal third (54%), crossing its middle third (31%), and running parallel to it along the gyrus rectus (15%). The FPA was present in 92% of the hemispheres, a mean of 10 ± 5 mm from the AcomA, always arising from the A2 and coursing anteriorly within the interhemispheric fissure towards the frontal pole. CONCLUSION: The RAH, FOA, and FPA can be differentiated by origin, course, and destination using the A1 segment, olfactory tract, and interhemispheric fissure, respectively, as surgical landmarks.