Endoscopic full-thickness dissection (EFTD) in the rectum: a case series.

BACKGROUND: Rectal endoscopic full- thickness dissection (EFTD) using a flexible colonoscope is an alternative to the well-established trans-anal endoscopic microsurgery (TEM) and the trans-anal minimally invasive surgery (TAMIS) techniques for resecting dysplastic or malignant rectal lesions. This study evaluated EFTD safety by analyzing outcomes of the first patients to undergo rectal EFTD at the University Hospital of North-Norway. METHODS: The first 10 patients to undergo rectal EFTD at the University Hospital of North-Norway April, 2016 and January, 2021, were included in the study. The procedural indications for EFTD were therapeutic resection of non-lifting adenoma, T1 adenocarcinoma (AC), recurrent neuroendocrine tumor (NET) and re-excision of a T1-2 AC. RESULTS: EFTD rectal specimen histopathology revealed three ACs, five adenomas with high-grade dysplasia (HGD), one NET and one benign lesion. Six procedures had negative lateral and vertical resection margins and in three cases lateral margins could not be evaluated due to piece-meal dissection or heat damaged tissue. Two patients experienced delayed post-procedural hemorrhage, one of whom also presented with a concurrent post-procedural infection. No serious complications occurred. CONCLUSION: Preliminary results from this introductory trial indicate that EFTD in the rectum can be conducted with satisfactory perioperative results and low risk of serious complications.

Metabolic effects two years after renal denervation in insulin resistant hypertensive patients. The Re-Shape CV-risk study.

BACKGROUND & AIMS: Denervation of renal sympathetic nerves (RDN) is an invasive endovascular procedure introduced as an antihypertensive treatment with a potential beneficial effect on insulin resistance (IR). We have previously demonstrated a reduction in blood pressure (BP) six months after RDN, but severe hepatic and peripheral IR, assessed by glucose tracer and two step hyperinsulinemic-euglycemic clamp (HEC), did not improve. The aim of the current study was to evaluate IR and adipokines profiles in relation to BP and arterial stiffness changes two years after RDN. METHODS: In 20 non-diabetic patients with true treatment-resistant hypertension, ambulatory and office BP were measured after witnessed intake of medications prior to, six and 24 months after RDN. Arterial stiffness index (AASI) was calculated from ambulatory BP. Insulin sensitivity (IS) was assessed using an oral glucose tolerance test (OGTT), the Homeostasis Model Assessment (HOMA-IR), HOMA-Adiponectin Model Assessment (HOMA-AD), the Quantitative Insulin Sensitivity Check Index (QUICKI), the Triglyceride and Glucose Index (TyG) and the Leptin-to-Adiponectin Ratio (LAR). These surrogate indices of IS were compared with tracer/HEC measurements to identify which best correlated in this group of patients. RESULTS: All measured metabolic variables and IS surrogate indices remained essentially unchanged two years after RDN apart from a significant increase in HOMA-AD. OGTT peak at 30 min correlated best with reduction in endogenous glucose release (EGR) during low insulin HEC (r = -0.6, p = 0.01), whereas HOMA-IR correlated best with whole-body glucose disposal (WGD) (r = -0.6, p = 0.01) and glucose infusion rate (r = -0.6, p = 0.01) during high insulin HEC. BP response was unrelated to IS prior to RDN. Nocturnal systolic BP and arterial stiffness before RDN correlated positively with a progression in hepatic IR at six-month follow-up. CONCLUSION: IR, adiponectin and leptin did not improve two years after RDN. There was no correlation between baseline IS and BP response. Our study does not support the notion of a beneficial metabolic effect of RDN in patients with treatment resistant hypertension.

Three-dimensional evaluation of dentoskeletal changes after posterior cross-bite correction by quad-helix or removable appliances.

The aim of the study was to evaluate in a three-dimensional manner the dentoskeletal changes after slow maxillary expansion. The sample consisted of 34 children with a unilateral, symmetrical posterior cross-bite. Half of the children were treated with a quad-helix and the rest with a removable appliance. Assessment of the changes was made with study casts, and frontal and lateral cephalograms, before treatment, at the end of the expansion, after a retention period of 3 months, and after a post-retention period of 3 months. The results showed that sufficient expansion of the dental arches took place in both groups. The expansion expressed in the molar region in the quad-helix group was mostly due to buccal translation of the teeth and in the removable appliance group due to buccal tipping. The quad-helix group showed somewhat greater basal expansion than the removable appliance group, though the basal expansion in both groups was rather small. A tendency towards an increase of the NL/ML angle characterized the removable appliance group, but the opposite pattern was present in the quad-helix group.

Controlled retraction of maxillary incisors.

The force characteristics inherent in the prefabricated PG retraction spring have been shown to be efficient for controlled movement of canines. In the present investigation, this spring was analyzed with regard to its applicability for controlled retraction of the maxillary incisors. A description of the required system of moments and horizontal and vertical forces, acting at both the active (alpha) and reactive (beta) units, is presented. The three-dimensional force system generated by specific modifications of the spring was registered in a bench testing device mounted with strain gauges, and the resultant data presented in a graphic. It is concluded that the PG retraction spring can be used as a module for controlled retraction of both canines and incisors. The magnitude of horizontal and vertical forces is kept within the anticipated physiologic limits and can be identified by the shape of the activated spring. Variability of the distance between the anterior and the posterior points of force attack has no significant influence on the horizontal and vertical forces produced. Only minor clinical adjustments are needed to modify the retraction spring from canine-to-incisor retraction.

Location of centres of resistance for maxillary anterior teeth measured on human autopsy material.

The location of the centre of resistance (CR) of various consolidated units of maxillary anterior teeth was determined in this study using human autopsy material. The units studied consisted of two central incisors, four incisors, and six anterior teeth. When horizontal forces were applied the CR for the two- and six-tooth units was located approximately 6.5 mm apical to the bracket position. For the four-tooth unit, CR was placed slightly more occlusally, the distance being 5.0 mm. Applying vertical forces CR was located about 13.0 mm posterior to the bracket position for the two- and four-tooth unit. The incorporation of the canines into the incisor segment resulted in a distal shift of CR of 6 mm. CR for the six anterior teeth was, thus, located on a line 3 mm behind the distal surface of the canines. Increasing force levels had little effect on the location of CR for a given unit.

Electronic determination of centres of rotation produced by orthodontic force systems.

A strain gauge measurement device with low force clip gauges, for measurement of initial tooth displacement in two dimensions has been developed. An experimental model simulating a maxillary central incisor is loaded with different known and controlled force systems. The resulting tooth displacements are described by the position of the centre of rotation and the generated angle of rotation for the total tooth movement. The effect of a single force, a moment, and force-moment combinations producing different moment to force ratios were studied. From these results the required force system needed to produce tooth movements with different centres of rotation for a central incisor of average root length are calculated. Furthermore, the model allows us to measure the accuracy of the measuring device by comparing results to analytical and laser holographic data, obtained on similar models. Some preliminary measurements and results, using human autopsy material are presented.

Biomechanical design and clinical evaluation of a new canine-retraction spring.

Use of the sectional arch technique facilitates the creation of an optimal force system fulfilling the biomechanical requirements imperative for planned tooth movements. Controlled canine retraction, usually in extraction cases, requires the creation of a biomechanical system to deliver a predetermined force and a relatively constant moment-to-force ratio in order to avoid distal tipping and rotation. The responsive couple delivered to the anchorage unit should be adjusted in such a way that no single tooth is subjected to unwanted side effects and that undesirable changes in the occlusal plane are avoided. On the basis of a series of theoretical considerations described in the present report, a canine-retraction spring was constructed from 0.016 X 0.022 inch stainless steel wire, the principal element being a double ovoid loop 10 mm in height. A "sweep" bend was incorporated to avoid unwanted side effects at the second premolar. Load deflection and moment/force curves were derived experimentally and demonstrate the ability of the spring to generate and maintain biomechanical conditions necessary for optimal canine retraction (that is, load deflection = 45 gm per millimeter of activation, antitip moment/force ratio of approximately 11:1, and antirotation moment/force ratio of approximately 7:1). The clinical applicability of the spring is demonstrated in the present report by the presentation of two treated cases.