Immediate Implant Placement in the Maxillary Aesthetic Zone: A Cone Beam Computed Tomography Study

This study aimed to investigate the factors that could be associated with the risk of labial cortical bone wall perforation with immediate implant placement (IIP) in the maxillary aesthetic zone, in a cone-beam computed tomography (CBCT) virtual study. CBCT exams from 126 qualified subjects (756 teeth) were included. Implants were virtually positioned in two different positions: in the long axis of the tooth (prosthetically-driven position) and in an ideal position in relation to adjacent anatomical structures (bone-driven position). Two different implant diameters were planned for each tooth position, namely, 3.75 and 4.3 mm for central incisors and canines, and 3.0 and 3.3 mm for lateral incisors. The incidence of perforation was nearly 80% and 5% for prosthetically- and bone-driven position, respectively. Factors associated with a higher risk of cortical bone wall perforation (bone-driven position), according to logistic regression analysis, were women, wider implants, Sagittal Root Position class IV, and decrease of the labial concavity angle. Perforation of the labial cortical bone wall can be greatly minimized when the implant is placed in a bone-driven position compared to a prosthetically-driven position. It is important to preoperatively evaluate the morphological features of the implant site for risk assessment and to individualize the treatment plan.

Estimating the Long-Term Reliability of Steel and Cast Iron Pipelines Subject to Pitting Corrosion

Water-injection, oil production and water-supply pipelines are prone to pitting corrosion that may have a serious effect on their longer-term serviceability and sustainability. Typically, observed pit-depth data are handled for a reliability analysis using an extreme value distribution such as Gumbel. Available data do not always fit such monomodal probability distributions well, particularly in the most extreme pit-depth region, irrespective of the type of pipeline. Examples of this are presented, the reasons for this phenomenon are discussed and a rationale is presented for the otherwise entirely empirical use of the ‘domain of attraction’ in extreme value applications. This permits a more rational estimation of the probability of pipe-wall perforation, which is necessary for asset management and for system-sustainability decisions.

Right Bundle Branch Block Morphology After Right Ventricular Endocardial Pacing – When Should a Cardiologist Begin to Worry ?

Even though the left bundle branch block (LBBB) morphology in the surface electrocardiogram (ECG) is expected after right ventricular endocardial pacing, the right bundle branch block (RBBB) morphology may be paradoxically seen in around 8 to 10% of patients. The paced RBBB morphology should be given special attention in terms of safe RV pacing or septal and free wall perforation. Simple techniques such as moving the leads V1-2 to one interspace lower than standard (Klein maneuver) and combining frontal QRS axis between -30° to -90°, precordial transition point at or within V3, and absence of S wave in lead I as an algorithmic approach may correctly identify the pacemaker lead in right ventricle with high sensitivity, specificity, and positive predictive value.

Left ventricular free wall perforation by a right ventricular pacemaker lead: a case report

Background Lead perforation is one of the major complications of pacemaker implantation, but cases of right ventricular (RV) lead perforation through the septum and left ventricle are rarely reported. We described a rare case of left ventricular (LV) free wall perforation by an RV lead and the management of this complication. Case summary An 84-year-old man was admitted with a dual-chamber pacemaker due to pacing failure caused by an RV lead fracture. New lead implantation was performed on the next day, but pacing failure occurred again on the second post-operative day (POD). We found the lead perforation on the fluoroscopy during temporary pacemaker insertion. Computed tomography scan and transthoracic echocardiogram showed that the added lead perforated through both the septum and LV free wall. A new lead was inserted on the fourth POD, and an off-pump open chest surgery for extraction of the penetrating lead was performed uneventfully on the 20th POD. Discussion We considered that some features of the lead (SelectSecure 3830-69, Medtronic) may be related to this complication, as the lead was very thin, had a non-retractable bare screw and was inserted with a dedicated delivery catheter. We have to be careful when performing implantation of this kind of lead to avoid such a rare complication.

Aircraft Impact Effects on an Aged NPP

The impact of an aircraft is widely known to be one of the worst events that can occur during the operation of a plant (classified for this reason as beyond design). This can become much more catastrophic and lead to the loss of strength of/collapse of the structures when it occurs in the presence of ageing (degradation and alteration) materials. Therefore, since the performance of all plant components may be affected by ageing, there is a need to evaluate the effect that aged components have on system performance and plant safety. This study addresses the numerical simulation of an aged Nuclear Power Plant (NPP) subjected to a military aircraft impact. The effects of impact velocity, direction, and location were investigated together with the more unfavorable conditions to be expected for the plant. The modelling method was also validated based on the results obtained from the experiments of Sugano et al., 1993. Non-linear analyses by means of finite element (FE) MARC code allowed us to simulate the performance of the reinforced concrete containment building and its impact on plant availability and reliability. The results showed that ageing increases a plant’s propensity to suffer damage. The damage at the impact area was confirmed to be dependent on the type of aircraft involved and the target wall thickness. The greater the degradation of the materials, the lower the residual resistance capacity, and the greater the risk of wall perforation.

Sharp recanalization of peripheral arterial chronic total occlusions

Peripheral arterial chronic total occlusions (CTOs) usually have calcified caps at either ends. When attempting endovascular recanalization, these calcified CTO caps may prevent the interventionist in crossing the lesion with conventional catheter and guidewire techniques. Using specialized CTO devices or re-entry devices can help crossing the CTO, but such devices are usually expensive, not always readily available and require specialist training prior to usage. “Sharp recanalization” is an alternative method of crossing the CTOs. If it is not possible to cross the CTO with conventional catheter and guidewire technique, one can take out the floppy end of the guidewire and use the stiff or the “sharp” end of the guidewire to break the hard CTO cap. Once the CTO cap is broken, the stiff end is replaced by the floppy end of the guidewire again to proceed with balloon angioplasty and/or stenting. In order to safely use the sharp recanalization technique while minimizing the risk of perforation, sharp recanalization should only be attempted once conventional methods have failed. The interventionist should plan sharp recanalization with the vascular path in mind and decide in advance how far s/he will proceed. It can be helpful to set a time limit together with the intervention team, past which the sharp recanalization attempt will be abandoned. Using straight catheters can help directing the stiff guidewire tip to the center of the vascular lumen and reduce the risk of sub intimal dissection or arterial wall perforation.

Clinical Features of Intra-Abdominal Abscess and Intestinal Free-Wall Perforation in Korean Patients with Crohn’s Disease: Results from the CONNECT Study

Background: In Crohn’s disease (CD), intra-abdominal abscess (IA) and intestinal free-wall perforation (IP) have a common mechanism of transmural inflammation; however, their manifestation is different. Objective: This study aimed to investigate differences in the clinical features between IA and IP in Korean patients with Crohn’s disease. Design: A retrospective cohort study. Setting: Thirty university hospitals and two local hospitals in Korea. Patients: Patients who were diagnosed with CD between July 1982 and December 2008 were enrolled. Main Outcome Measures: Clinical characteristics of IA and IP. Results: Among 1286 patients with CD, 147 (11.4%) had IA and 83 (6.5%) had IP. IA patients were younger than those of IP (24.2 ± 8.6 vs. 30.4 ± 11.1 years, p = 0.001). Location and behavior were significantly different between IA and IP (p = 0.035 and 0.021). In multivariate analyses, perianal fistula was not associated with increased risk of IA and IP, while intestinal stricture was associated with increased risk of IA (OR: 2.72, p < 0.0001) and IP (OR: 2.76, p < 0.0001). In subgroup analyses, 55 (36.5%) IA patients were diagnosed at the diagnosis of CD, and 92 (63.5%) during follow-up of CD, while 47 (56.6%) IP patients were diagnosed at the diagnosis of CD, and 36 (43.3%) during follow-up of CD. Conclusions: There are several differences in the clinical features of IA and IP in Korean patients with CD. The development mechanism is considered as identical, but further investigation should be needed for clinical implication.

Esophagogastric polyurethane bezoar complicated by stomach wall microperforation and acute peritonitis: case report

Background Bezoars are collections of indigestible material in the gastrointestinal tract, mostly described in children. Polyurethane “plastobezoars” consisting of composites used in the construction industry are rarely described bezoars formed in the esophagus and stomach, causing gastrointestinal obstruction, usually necessitating gastrectomy. We describe an unusual presentation of polyurethane bezoar with a volcanic rock consistency, that caused gastrointestinal obstruction and perforation of the stomach wall. Case presentation A 39-year-old man, a construction worker, was referred with signs and symptoms of high gastrointestinal obstruction and abdominal pain. Esophagoscopy revealed a foreign body in the esophagus, 20 cm from the incisor line, causing its obstruction. The attempt to collect the material with forceps failed as the material was too hard. Spiral computed tomography visualized a wide, gas-filled esophagus and a large stomach. The patient with symptoms of acute peritonitis was operated. There were several microperforations of the stomach wall, caused by sharp bezoar fragments that filled the upper one-third of the stomach and lower part of the esophagus. After a longitudinal stomach incision, the bezoar was bluntly dissected from the wall and removed, and the stomach microperforations were closed by wall duplication. After the operation, the patient confessed to drinking, of his own free will, a two-component building foam used to seal pipes. The patient started normal feeding on the 4th day and was discharge home. Conclusions Polyurethane bezoars may cause stomach wall perforation and acute peritonitis. Computed tomography has limited usefulness in patients with polyurethane bezoars due to their low specific weight.