Engineering strategies towards overcoming bleeding and glial scar formation around neural probes

Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?

Partial Vaginectomy, Complete Vaginectomy, Partial Vestibule-Vaginectomy, Vulvo-Vestibule-Vaginectomy and Vulvo-Vestibulectomy: Different Surgical Procedure in Order to Better Approach Vaginal Diseases

Total or partial vulvo-vaginectomy or vaginectomy are not routinely performed due to the complexity of the techniques and because they are considered radical treatments. Little information can be found in the literature, as the same technique is often named in a different way by different authors, confusing the reader. Therefore, the aim of this essay is to describe five different surgical techniques: partial vaginectomy, complete vaginectomy, partial vestibule-vaginectomy, vulvo-vestibule-vaginectomy and vulvo-vestibulectomy. All techniques are described on the basis of the correct identification of the anatomical nomenclature related to structures involved in surgery, in order to give a more precise and unambiguous description and execution of surgical techniques. Moreover, possible intraoperative and perioperative complications and the authors’ clinical experience in 33 dogs are described. All techniques are well tolerated and could be curative in case of benign or malignant tumours that have not yet metastasized and palliative in other cases. Moreover, they are also useful for therapeutic purposes for chronic vaginitis, severe vaginal cysts or congenital abnormalities. It is our opinion that having five different available techniques to approach vaginal disease is useful to perform the best surgery according to the clinical findings, patient’s characteristics, technique invasiveness and whether it is palliative or not.

Evaluation of VEP Parameters in Patients Before and After Cardiopulmonary By-Pass Surgery

Introduction: Coronary bypass surgery is emphasized in aetiology of ischemic optic neuropathy. Our aim in this study was to investigate the pattern visual evoked potentials (PVEP) in patients before and after coronary bypass surgery.Methods: Thirty-one patients were included in the study. After a full ophthalmological evaluation, PVEP was assesed in the pre and postoperative periods. Operative times, hematological parameters, blood pressures, number of transfusions, body temperatures, anaesthetic drugs and systemic illnesses were recorded for each patient. Results: The mean age of the patients were 59±10.4 years. There was 22 men and 9 women in the study. Only 3 of them needed transfusion during the surgery. The mean duration of the surgery was 3.2±0.7 hours. None of the patients had a history of visual disturbance or postoperative ischemic optic neuropathy. The mean VEP P100 amplitude was not statistically significantly different but the mean VEP P100 latency showed statistically significant difference between the preoperative and postoperative periods. (p=0.014) This significance was more appereant in patients with systemic illnesses. (p= 0.023) There was a positive correlation between the age and VEP P100 latency. (r = 0.402, p< 0.05) Conclusions: Although surgical techniques and equipments are developing each day in the field of cardiopulmonary bypass surgery, the contributing factors such as hypothermia, anemia and diabetes still seem to affect neurophysiological functions even after a noncomplicated surgery.

Reducing Morbidity and Mortality in Patients With Coarctation Requires Systematic Differentiation of Impacts of Mixed Valvular Disease on Coarctation Hemodynamics

Background Despite ongoing advances in surgical techniques for coarctation of the aorta (COA) repair, the long‐term results are not always benign. Associated mixed valvular diseases (various combinations of aortic and mitral valvular pathologies) are responsible for considerable postoperative morbidity and mortality. We investigated the impact of COA and mixed valvular diseases on hemodynamics. Methods and Results We developed a patient‐specific computational framework. Our results demonstrate that mixed valvular diseases interact with COA fluid dynamics and contribute to speed up the progression of the disease by amplifying the irregular flow patterns downstream of COA (local) and exacerbating the left ventricular function (global) (N=26). Velocity downstream of COA with aortic regurgitation alone was increased, and the situation got worse when COA and aortic regurgitation coexisted with mitral regurgitation (COA with normal valves: 5.27 m/s, COA with only aortic regurgitation: 8.8 m/s, COA with aortic and mitral regurgitation: 9.36 m/s; patient 2). Workload in these patients was increased because of the presence of aortic stenosis alone, aortic regurgitation alone, mitral regurgitation alone, and when they coexisted (COA with normal valves: 1.0617 J; COA with only aortic stenosis: 1.225 J; COA with only aortic regurgitation: 1.6512 J; COA with only mitral regurgitation: 1.3599 J; patient 1). Conclusions Not only the severity of COA, but also the presence and the severity of mixed valvular disease should be considered in the evaluation of risks in patients. The results suggest that more aggressive surgical approaches may be required, because regularly chosen current surgical techniques may not be optimal for such patients.

A Review of Strategies to Improve Biomechanical Fixation in the Cervical Spine

Study Design Systematic review. Objectives Review the surgical techniques and construct options aimed at improving the biomechanical strength of cervical constructs. Methods A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of the MEDLINE, Embase, and Cochrane Library databases was performed to identify all studies examining biomechanical strategies utilized in the osteoporotic cervical spine. Screening was performed in duplicate for all stages of the review process. Results An initial search returned 3887 articles. After deletion of duplications and review of abstracts and full text, 39 articles met inclusion criteria. Overall, the surgical techniques reviewed aimed at obtaining rigid fixation in the setting of poor bone quality, or dispersing the forces at the bone-implant interface. We identified 6 key techniques to improve biomechanical fixation. These include bicortical fixation, appropriate screw selection (size and trajectory), PMMA augmentation, load sharing techniques, consideration of ancillary fixation around the occipitocervical junction, and supplementing the construct with post-operative collar or halo. Conclusion The summation of the literature highlights a framework of modalities available to surgeons to improve biomechanical fixation in the cervical spine. While these may improve construct strength in the setting of osteoporosis, there is a paucity of evidence available to make recommendations in this patient population.

Surgical left atrial appendage closure: success rate and its relationship with cerebrovascular accident

Background: Several surgical procedures such as excision or exclusion are recommended for the closure of the left atrial appendage (LAA). This study was conducted with the aim to evaluate the success rate of different surgical techniques for LAA closure, their respective complications, and the rate of post-surgical cerebrovascular accident (CVA). Methods: This retrospective study included 150 consecutive patients who underwent LAA closure most commonly after mitral valve surgery within 3 to 6 months after surgery. An expert echocardiographic fellow collected the data on patients’ surgical LAA closure methods and history of CVA, types of prosthetic valves, mortality, and bleeding. Results: The failure rate for complete LAA closure was 36.7% (55 patients) in our study. The greatest success rate of complete LAA closure was seen in purse-string method (75.5%), followed by resection method (71.4%), while the lowest success rate (≈ 33.3%) was observed in ligation method. A significant relationship was observed between clots on the surface of metallic valve and postoperative CVA (P = 0.001; likelihood ratio: 32). significant relationship between partial LAA closure and the incidence of post-surgical CVA (P > 0.050). Conclusion: We observed the highest success rate of complete LAA closure in purse-string method followed by resection method. Interestingly, our results showed that despite the higher rate of residual LAA clot in cases of partial LAA closure, the occurrence of post-surgical CVA was mostly related to the presence of clots on the surface of metallic mitral prostheses rather than the presence of partial LAA closure.

Laparoscopic Liver Resection: Surgical Techniques

Laparoscopic liver resection has evolved from a technique to remove small anterior liver lesions with smaller incisions to a major method for the performance of almost every type of liver resection.

PUTH Grading System for Urinary Tumor With Supradiaphragmatic Tumor Thrombus: Different Surgical Techniques for Different Tumor Characteristics

PurposeTo explore the different treatment strategies for urinary tumors with Mayo IV thrombus.Materials and MethodsWe retrospectively analyzed the patients with Mayo IV thrombus in Peking University Third Hospital from January 2014 to April 2021. We used the Peking University Third Hospital (PUTH) grading system to classify urinary tumors with supradiaphragmatic thrombus. PUTH-A referred to the filled thrombus whose tip just reached above the diaphragm, or the thrombus entering the right atrium (&lt; 2cm). PUTH-B referred to the filled thrombus entering the right atrium (&gt; 2cm), or the thrombus invading the wall of the inferior pericardial vena cava. Detailed techniques were described for various scenarios. Clinicopathological data and perioperative outcomes were reported. Group difference statistical analysis was performed.ResultsA total of 26 cases of urinary tumors with supradiaphragmatic IVC thrombus (Mayo grade IV) underwent treatment were enrolled in this study. 19 patients in the PUTH-A group received the open approach without sternotomy and cardiopulmonary bypass. Seven patients in the PUTH-B group received open thoracotomy assisted by cardiopulmonary bypass. No intraoperative death occurred. After 56 months of follow-up, 46.2% (12 of 26) patients died of all causes. Estimated 1-year, 2-year, and 3-year overall survival were 72.0% (95% CI, 54.4%-89.6%), 58.2% (95% CI, 38.0%-78.4%), and 52.4% (95% CI, 31.2%-73.6%), respectively.ConclusionsWe introduced the PUTH grading system for the characteristics of urinary tumors with supradiaphragmatic tumor thrombus, and selected different surgical techniques according to different classifications. This grading system was relatively feasible and effective.