Gastrointestinal bleeding
Michael JG Farthing, Anne B Ballinger in Drug Therapy for Gastrointestinal and Liver Diseases, 2019
The majority of fissures have no underlying cause; however, they may be associated with Crohn’s disease, ulcerative colitis or sexually transmitted diseases. There is often spasm of the anal sphincter associated with anal fissures and the maximum resting anal pressure (which relates to internal anal sphincter smooth muscle activity) is often raised.13 It has been suggested that this spasm perpetuates the ulceration and reduces healing through localized ischaemia and trauma to the lining of the canal.14 Angiographic studies have demonstrated that the posterior commissure is poorly perfused, and this where most idiopathic fissures occur. Treatments therefore have generally focused on reducing the sphincter pressure through surgical and pharmacological approaches.
Surgical repair of primary deep vein valve incompetence
Peter Gloviczki, Michael C. Dalsing, Bo Eklöf, Fedor Lurie, Thomas W. Wakefield, Monika L. Gloviczki in Handbook of Venous and Lymphatic Disorders, 2017
The original description by Kistner1 utilized a longitudinal incision between the two valve cusps cutting through the anterior commissural apex (Figure 43.8). The incision is started 10–15 mm below the valve attachment lines and extended upwards through the commissural apex, keeping the cusps in view to avoid damage (the valves can droop or even prolapse down in some cases). The incision allows the valve station to be laid open like pages in a book, providing excellent exposure of redundant cusps. Frequent irrigation with saline is necessary to visualize the translucent valve cusps and their free edges. By using 7–0 polypropylene sutures, the valve edges are gathered like the pleats of a curtain and tacked to the commissural apex with the knot placed outside. A single double-needled suture can be used at the undivided posterior commissure. Separate sutures will be necessary at each half of the divided anterior commissure. Approximately 20% of the valve edges at each commissure will need to be tacked in this fashion. Some subjective judgment is required in deciding when enough valve tightening has been achieved, as valve competency cannot be tested until after the venotomy had been closed. Closure has to be meticulous, with everting sutures and good intimal apposition minimizing the chances of a potential nidus site for thrombus formation.
Syringomyelia and lower urinary tract dysfunction
Jacques Corcos, David Ginsberg, Gilles Karsenty in Textbook of the Neurogenic Bladder, 2015
Gardner’s theory2 In the 1950s, Gardner revolutionized the physiopathologic concepts of syringomyelia, introducing the notion of a pathogenic role of cerebrospinal fluid (CSF) dynamics. This primitive embryologic disorder comprises a lack or late opening of the roof orifices of the fourth ventricle that links the great cistern with the perimedullary and pericerebral subarachnoid spaces. Thus, a CSF hyperpressure is responsible for downward dilation of the spinal central canal. At birth, this hydromyelia bursts into a zone of lower resistance, the gray posterior commissure. It generates the syringomyelic cavity that will have a permanent tendency to extend. Prolapse of the cerebellar tonsils, which by itself can hamper CSF circulation, and the cervico-occipital bony abnormalities would be consequences of the hydroencephalomyelia (Arnold–Chiari malformation).
Altered dynamic parahippocampus functional connectivity in patients with post-traumatic stress disorder
Published in The World Journal of Biological Psychiatry, 2021
Hui Juan Chen, Rongfeng Qi, Jun Ke, Jie Qiu, Qiang Xu, Zhiqiang Zhang, Yuan Zhong, Guang Ming Lu, Feng Chen
Magnetic resonance imaging scans were conducted at Hainan General Hospital using a 3 Tesla MR scanner (Skyra, Siemens Medical Solutions, Erlangen, Germany) equipped with a 32 channel standard head coil. Subjects’ heads were immobilised using a foam pad and a Plexiglas head cradle. Whole brain resting-state functional images were obtained using an echo-planar imaging sequence with the following parameters: TR/TE = 2000/30 ms, flip angle = 90°, FOV = 230 × 230 mm2, matrix = 64 × 64, 35 slices, slice thickness = 3.6 mm, no intersection gap, and total volume number = 250. The sections were placed approximately parallel to the anterior commissure-posterior commissure line. High resolution T1-weighted 3 D anatomical images were also acquired with a sagittal magnetization-prepared rapid gradient echo sequence for later co-registration and normalisation (TR/TE = 2300/1.97 ms, flip angle = 9°, FOV = 256 × 256 mm2, matrix = 256 × 256, 176 slices, slice thickness = 1 mm). Each fMRI scan lasted for 500 seconds. During the functional scanning, subjects were instructed to lie quietly, keep their eyes closed, and let their mind wander without falling asleep.
Experience to prevent wire tethering in deep brain stimulation from a single center
Published in Neurological Research, 2021
Dongliang Wang, Jiayu Liu, Qingpei Hao, Hu Ding, Bo Liu, Zhi Liu, Haidong Song, Jia Ouyang, Ruen Liu
Briefly, the 3.0 T magnetic resonance imaging (MRI) was carried out 1–3 days before surgery. The imaging scanner was aligned parallel to the anterior commissure–posterior commissure line as closely as possible and used a specific sequence (3DT1, axial, coronal and sagittal T2-weighted images with 1.0 mm slice thickness and no spacing). A Leksell stereotactic head frame was mounted on the patient’s skull on the day of surgery under local anesthesia and then underwent stereotactic cranial computed tomography (1.0 mm slice thickness and no spacing). The MRI was integrated into the computed tomography (CT)-based three-dimensional stereotactic coordinate system by landmark-based image fusion. The targets and trajectory of the electrode implantation were calculated and determined using the Leksell SurgiPlan station (Elekta, Stockholm, Sweden). Under local anesthesia, the surgical incision was made according to the calculated target coordinates, and a hole was drilled through the skull. The electrodes for subthalamic nucleus (STN) were PINS L301 with four platinum–iridium cylindrical surface contacts, and each contact was 1.27 mm in diameter and 1.5 mm in length and separated by 0.5 mm. The electrodes for globus pallidus internus (GPi) were PINS L302, which had contacts of the same size but separated by 1.5 mm. The ultimately precise target was confirmed by anatomical location, and the signal of intraoperative microelectrode stimulation and the symptoms were relieved intraoperatively.
Pure endoscopic resection of pineal region tumors through supracerebellar infratentorial approach with ‘head-up’ park-bench position
Published in Neurological Research, 2023
Wei Hua, Hao Xu, Xin Zhang, Guo Yu, Xiaowen Wang, Jinsen Zhang, Zhiguang Pan, Wei Zhu
Intraoperative bleeding and loss of orientation are the main challenges of endoscopic approach [32]. For hyperaemic tumors, different techniques (described in the Methods section) can be performed to control the massive bleeding. It can show a big advantage in accessing the feeding artery, when the blood mainly comes from the posterior cerebral artery (PCA). The excellent illumination and view of the vascular structures was offered by the scope, thereby reducing the risk of haemorrhage [15]. Gravity reduced the pooling of blood in the operative field [8]. Studies have shown that there is a significant reduction in mean blood loss in endoscopic approaches [34]. Neuro-navigation and relevant landmarks, such as the aqueduct, the pineal recess, the suprapineal recess, and the posterior commissure, could guide the approach and resection.
Related Knowledge Centers
- Cerebral Aqueduct
- Epithalamus
- Oculomotor Nucleus
- Periaqueductal Gray
- Pretectal Area
- Superior Colliculus
- Medial Longitudinal Fasciculus
- Thalamus
- Pupillary Light Reflex
- Edinger–Westphal Nucleus