Electrode montage-dependent intracranial variability in electric fields induced by cerebellar transcranial direct current stimulation

Transcranial direct current stimulation (tDCS) is an increasingly popular tool to investigate the involvement of the cerebellum in a variety of brain functions and pathologies. However, heterogeneity and small effect sizes remain a common issue. One potential cause may be interindividual variability of the electric fields induced by tDCS. Here, we compared electric field distributions and directions between two conventionally used electrode montages (i.e., one placing the return electrode over the ipsilateral buccinator muscle and one placing the return electrode [25 and 35 cm2 surface area, respectively] over the contralateral supraorbital area; Experiment 1) and six alternative montages (electrode size: 9 cm2; Experiment 2) targeting the right posterior cerebellar hemisphere at 2 mA. Interindividual and montage differences in the achieved maximum field strength, focality, and direction of current flow were evaluated in 20 head models and the effects of individual differences in scalp–cortex distance were examined. Results showed that while maximum field strength was comparable for all montages, focality was substantially improved for the alternative montages over inferior occipital positions. Our findings suggest that compared to several conventional montages extracerebellar electric fields are significantly reduced by placing smaller electrodes in closer vicinity of the targeted area.

Classification of postoperative edema based on the anatomic division with mandibular third molar extraction

Purpose Several investigations have been performed for a postoperative edema after extraction, but the results have been controversial due to low objectivity or poorly reproducible assessments of the edema. The aim of this study was to suggest a classification and patterns of postoperative edema according to the anatomical division associated with extraction of mandibular third molar as a qualitative evaluation method. Methods This study was conducted forty-four mandibular third molars extracted and MRI was taken within 48 h after extraction. The postoperative edema space was classified by MRI (one anatomic component—buccinator muscle—and four fascial spaces—supra-periosteum space, buccal space, parapharyngeal space, and lingual space), and evaluated independently by two examiners. The inter-examiner reliability was calculated using Kappa statistics. Results The evaluation of buccinator muscle edema showed good agreement and the fascial spaces showed constant high agreement. The incidence of postoperative edema was high in the following order: supra-periosteum space (75.00%), buccinator muscle (68.18%), parapharyngeal space (54.55%), buccal space (40.91%), and lingual space (25.00%). Conclusion Postoperative edema could be assessed clearly by each space, which showed a different tendency between the anatomic and fascial spaces.

Management of Traumatic Herniation of Buccal Fat Pad in a 22-month-old Child: A Case Report

The buccal fat pad is an encapsulated mass located within the buccal facial spaces. It is relatively large in neonate and infants. A tiny perforation on buccal mucosa, fascia or buccinator muscle can lead to the herniation of buccal fat pad in young children. Trauma is the most common etiology. Such situation demands careful examination of oral cavity and thorough history taking to avoid any misdiagnosis. This paper reports a clinical presentation and management of herniation of buccal fat pad on a 22-month-old-girl following trauma to her left cheek region with sugarcane.

Identification of the Preferred Interventional Approach to Trigeminal Ganglion Using Three-Dimensional Reconstruction Stereoscopic Model

Trigeminal ganglion injection is a common procedure for many facial pain syndromes, including trigeminal neuralgia. The procedure is usually done under fluoroscopy guidance to target at the foramen ovale where lies the trigeminal ganglion and the mandibular branch of trigeminal nerve exits. In this project, Amira® software was used to create 3D structures that can be visualized stereoscopically and involve the structures to study the procedure pathway. The detailed anatomical structures include the skin, skull, external and internal pterygoid muscle, masseter muscle, buccinator muscle, external carotidartery and its branches, internal carotid artery and its branches, vertebral artery, trigeminal ganglion and its branches, internal jugular vein, and parotid gland were created. The structures’ relationships and potential complications are described. The 3D model is used to guide and educate students about safe procedure pathways and may potentially be used to evaluate and modify procedures scientifically.

Cheek Dimpleplasty: A New Classification of Described Procedures

Cheek dimpleplasty has become a popular request amongst patients requesting cosmetic surgery. Since the first reported dimpleplasty in 1962, there have been many reported procedures in the literature for cheek dimple creation. Some of the procedures described by various authors as “novel” are actually similar if not identical to existing procedures. This study reviews the different procedures of cheek dimple creation and provides the first ever systematic classification for these techniques. EMBASE, Cochrane library, Ovid medicine, and PubMed databases were searched from its inception to June of 2019. We included all studies describing the surgical creation of cheek dimples. The studies were reviewed, and the different procedures were cataloged. We then proposed a new classification system for these procedures based on their common characteristics. The study included 12 articles published in the English language that provided a descriptive procedure for cheek dimple creation. We classified the procedures into 3 broad categories and subcategories. Type 1 procedures are nonexcisional myocutaneous dimpleplasties. In these procedures, the buccinator muscle is not excised. In type 1A, the suture used to create the adhesion traverses the epidermis. In type 1B, the suture does not traverse the epidermis, rather, the suture travels up into the dermis and returned back to the mucosa. Type 2 procedures are excisional dimpleplasties. In these procedures, the buccinator muscle is excised with (open) or without (closed) the excision of the mucosa. Type 3 procedures are incisional dimpleplasty. In these procedures, the muscle is incised and fixed to the dermis. Each of these groups of procedures has potential unique advantages and disadvantages. There are multiple procedures reported in the English language literature for the creation of cheek dimples. Most of the procedures are based on similar concept with minor variations. Our classification system, the Opoku-Simone Classification, will help facilitate communication when describing the different configurations of these procedures. Procedure within each group has similar potential advantages and disadvantages.