Evaluating the surveillance for swine dysentery and progressive atrophic Rhinitis in closed multiplier herds using Scenario tree modelling

Background: The Swiss pig population enjoys a favourable health situation. To further promote this, the Pig Health Service (PHS) conducts a surveillance program in affiliated herds: closed multiplier herds with the highest PHS-health and hygiene status have to be free from swine dysentery and progressive atrophic rhinitis and are clinically examined four times a year, including laboratory testing. Besides, four batches of pigs per year are fattened together with pigs from other herds and checked for typical symptoms (monitored fattening groups (MF)). While costly and laborious, little was known about the effectiveness of the surveillance to detect an infection in a herd. Therefore, the sensitivity of the surveillance for progressive atrophic rhinitis and swine dysentery at herd level was assessed using scenario tree modelling, a method well established at national level. Furthermore, its costs and the time until an infection would be detected were estimated, with the final aim of yielding suggestions how to optimize surveillance. Results: For swine dysentery, the median annual surveillance sensitivity was 96.7 %, mean time to detection 4.4 months, and total annual costs 1022.20 Euro/herd. The median component sensitivity of active sampling was between 62.5 and 77.0 %, that of a MF between 7.2 and 12.7 %. For progressive atrophic rhinitis, the median surveillance sensitivity was 99.4 %, mean time to detection 3.1 months and total annual costs 842.20 Euro. The median component sensitivity of active sampling was 81.7 %, that of a MF between 19.4 and 38.6 %. Conclusions: Results indicate that total sensitivity for both diseases is high, while time to detection could be a risk in herds with frequent pig trade. From all components, active sampling had the highest contribution to the surveillance sensitivity, whereas that of MF was very low. To increase efficiency, active sampling should be intensified (more animals sampled) and MF abandoned. This would significantly improve sensitivity and time to detection at comparable or lower costs. The method of scenario tree modelling proved useful to assess the efficiency of surveillance at herd level. Its versatility allows adjustment to all kinds of surveillance scenarios to optimize sensitivity, time to detection and/or costs.

Measurement of fecal elastase improves performance of newborn screening for cystic fibrosis.

BACKGROUND The aim of newborn screening (NBS) for CF is to detect children with 'classic' CF where early treatment is possible and improves prognosis. Children with inconclusive CF diagnosis (CFSPID) should not be detected, as there is no evidence for improvement through early treatment. No algorithm in current NBS guidelines explains what to do when sweat test (ST) fails. This study compares the performance of three different algorithms for further diagnostic evaluations when first ST is unsuccessful, regarding the numbers of children detected with CF and CFSPID, and the time until a definite diagnosis. METHODS In Switzerland, CF-NBS was introduced in January 2011 using an IRT-DNA-IRT algorithm followed by a ST. In children, in whom ST was not possible (no or insufficient sweat), 3 different protocols were applied between 2011 and 2014: in 2011, ST was repeated until it was successful (protocol A), in 2012 we proceeded directly to diagnostic DNA testing (protocol B), and 2013-2014, fecal elastase (FE) was measured in the stool, in order to determine a pancreas insufficiency needing immediate treatment (protocol C). RESULTS The ratio CF:CFSPID was 7:1 (27/4) with protocol A, 2:1 (22/10) with protocol B, and 14:1 (54/4) with protocol C. The mean time to definite diagnosis was significantly shorter with protocol C (33days) compared to protocol A or B (42 and 40days; p=0.014 compared to A, and p=0.036 compared to B). CONCLUSIONS The algorithm for the diagnostic part of the newborn screening used in the CF centers is important and affects the performance of a CF-NBS program with regard to the ratio CF:CFSPID and the time until definite diagnosis. Our results suggest to include FE after initial sweat test failure in the CF-NBS guidelines to keep the proportion of CFSPID low and the time until definite diagnosis short.

What does local tenderness say about the origin of pain? An investigation of cervical zygapophysial joint pain

BACKGROUND: Mechanical pain sensitivity is assessed in every patient with pain, either by palpation or by quantitative pressure algometry. Despite widespread use, no studies have formally addressed the usefulness of this practice for the identification of the source of pain. We tested the hypothesis that assessing mechanical pain sensitivity distinguishes damaged from healthy cervical zygapophysial (facet) joints. METHODS: Thirty-three patients with chronic unilateral neck pain were studied. Pressure pain thresholds (PPTs) were assessed bilaterally at all cervical zygapophysial joints. The diagnosis of zygapophysial joint pain was made by selective nerve blocks. Primary analysis was the comparison of the PPT between symptomatic and contralateral asymptomatic joints. The secondary end points were as follows: differences in PPT between affected and asymptomatic joints of the same side of patients with zygapophysial joint pain; differences in PPT at the painful side between patients with and without zygapophysial joint pain; and sensitivity and specificity of PPT for 2 different cutoffs (difference in PPT between affected and contralateral side by 1 and 30 kPa, meaning that the test was considered positive if the difference in PPT between painful and contralateral side was negative by at least 1 and 30 kPa, respectively). The PPT of patients was also compared with the PPT of 12 pain-free subjects. RESULTS: Zygapophysial joint pain was present in 14 patients. In these cases, the difference in mean PPT between affected and contralateral side (primary analysis) was −6.2 kPa (95% confidence interval: −19.5 to 7.2, P = 0.34). In addition, the secondary analyses yielded no statistically significant differences. For the cutoff of 1 kPa, sensitivity and specificity of PPT were 67% and 16%, respectively, resulting in a positive likelihood ratio of 0.79 and a diagnostic confidence of 38%. When the cutoff of 30 kPa was considered, the sensitivity decreased to only 13%, whereas the specificity increased to 95%, resulting in a positive likelihood ratio of 2.53 and a diagnostic confidence of 67%. The PPT was significantly lower in patients than in pain-free subjects (P < 0.001). CONCLUSIONS: Assessing mechanical pain sensitivity is not diagnostic for cervical zygapophysial joint pain. The finding should stimulate further research into a diagnostic tool that is widely used in the clinical examination of patients with pain.

Rapidly excised and cryofixed rat tissue

All preparation efforts of biological samples in electron microscopy are focused to preserve structures as close as possible to the native state. To achieve this goal with tissues, it is of advantage to have a very short time between excision and fixation. The most common approach is chemical fixation: cross-linking of the tissue samples with aldehydes followed by postfixation with osmium tetroxide. Here, the fastest approach for tissue samples is perfusion. However, the diffusion of the fixation solution from blood vessels into the depth of the tissue is still slow and does not allow an overall instant fixation of a single cell. As a result, osmotic effects become evident (swelling or shrinkage of cell organelles). Another possibility is to take a tissue sample from the experimental animal. Excision of tissue can last quite some time, which results in even more pronounced autolytic induced osmotic effects. Furthermore, the animal does not survive the procedure in most cases. Alternatively, microbiopsies are an elegant technique to rapidly excise small quantities of tissue. Some tissues, such as liver and muscle, may be obtained using a non-lethal approach. To avoid the artifacts introduced by chemical fixation, high-pressure freezing of microbiopsies (brain, liver, kidney, and muscle) is a powerful alternative to chemical fixation. Here, we describe the microbiopsy method, and high-pressure freezing/freeze-substitution (HPF/FS) as a follow-up procedure. Cryosectioning of high-pressure frozen samples is optimally preserving the ultrastructure; however, it is not considered to be a routine approach yet.

Respiratory muscle activity related to flow and lung volume in preterm infants compared with term infants

Infants with chronic lung disease (CLD) have a capacity to maintain functional lung volume despite alterations to their lung mechanics. We hypothesize that they achieve this by altering breathing patterns and dynamic elevation of lung volume, leading to differences in the relationship between respiratory muscle activity, flow and lung volume. Lung function and transcutaneous electromyography of the respiratory muscles (rEMG) were measured in 20 infants with CLD and in 39 healthy age-matched controls during quiet sleep. We compared coefficient of variations (CVs) of rEMG and the temporal relationship of rEMG variables, to flow and lung volume [functional residual capacity (FRC)] between these groups. The time between the start of inspiratory muscle activity and the resulting flow (tria)--in relation to respiratory cycle time--was significantly longer in infants with CLD. Although FRC had similar associations with tria and postinspiratory activity (corrected for respiratory cycle time), the CV of the diaphragmatic rEMG was lower in CLD infants (22.6 versus 31.0%, p = 0.030). The temporal relationship of rEMG to flow and FRC and the loss of adaptive variability provide additional information on coping mechanisms in infants with CLD. This technique could be used for noninvasive bedside monitoring of CLD.

Microfenestration using the CUSA Excel ultrasonic aspiration system in chondrodystrophic dogs with thoracolumbar disk extrusion: a descriptive cadaveric and clinical study

OBJECTIVE: To describe an ultrasonic surgical aspirator assisted disk fenestration technique in dogs. STUDY DESIGN: Descriptive cadaveric and prospective clinical study. ANIMALS: Fresh Beagle cadavers (n=5) and 10 chondrodystrophic dogs with thoracolumbar disk extrusion. METHODS: Cadaveric study: Intervertebral disks T12-L2 were fenestrated with the CUSA Excel in 5 Beagle cadavers, and fenestration efficacy assessed by morphologic examination of the completeness of fenestration and size of annulotomy. Clinical study: the affected intervertebral disk was fenestrated in 10 chondrodystrophic dogs treated by hemilaminectomy for thoracolumbar disk disease. Efficacy of fenestration was evaluated. RESULTS: Mean time necessary to perform CUSA assisted fenestration was 8 minutes (range, 5-10 minutes) for each disk in cadavers and patients. In cadaver spines, removal of the nucleus pulposus was complete in 11/15 disks. In 4 disks, remnants of nucleus pulposus material were observed on the contralateral side. Nuclear material was normal in 9/15 disks and showed evidence of chondroid degeneration on histopathologic examination in the 6 disks. Median annulotomy size was 3 mm. Clinically, no signs of early recurrence were observed and all dogs recovered uneventfully. CONCLUSIONS: CUSA assisted fenestration is a safe and efficient method of fenestration for removal of most of the nucleus pulposus through a limited annulotomy.

Prevalence of asymptomatic and electrically undetectable intracardiac inside-out abrasion in silicon-coated Riata® and Riata® ST implantable cardioverter-defibrillator leads

BACKGROUND: Recently, several cases of symptomatic and/or electrically detectable intracardiac inside-out abrasions in silicon-coated Riata® and Riata® ST leads have been described. However, the prevalence in asymptomatic patients with unremarkable implantable cardioverter defibrillator (ICD) interrogation is unknown. The aim of this study was to determine the prevalence of asymptomatic and electrically undetectable intracardiac inside-out abrasion in silicon-coated Riata® and Riata® ST leads. METHODS: All 52 patients with an active silicone-coated Riata® and Riata® ST lead followed up in our outpatient clinic were scheduled for a premature ICD interrogation and a biplane chest radiograph. When an intracardiac inside-out abrasion was suspected, this finding was confirmed by fluoroscopy. RESULTS: Mean time since implantation was 71±18months. An intracardiac inside-out abrasion was confirmed by fluoroscopy in 6 patients (11.5%). Mean time from lead implantation to detection of intracardiac inside-out abrasion was 79±14months. In all patients with an intracardiac inside-out abrasion, ICD interrogation showed normal and stable electrical parameters. Retrospectively, in 4 of these 6 patients, a coronary angiography performed 25±18months before diagnosis of intracardiac inside-out abrasion already showed the defect. Despite undetected intracardiac inside-out abrasion, 2 of these 4 patients experienced adequate antitachycardia pacing and ICD-shocks. ICD leads were replaced in all 6 patients. CONCLUSIONS: The prevalence of asymptomatic intracardiac inside-out abrasion in silicon-coated Riata® and Riata® ST leads is higher than 10% when assessed by fluoroscopy, and most intracardiac inside-out abrasions are not detectable by ICD interrogation.

Hepatitis A vaccines and the elderly

Hepatitis A virus (HAV) exposure in unprotected adults may cause severe and serious symptoms, with risk of both morbidity and mortality increasing with age. As seroprevalence of HAV is low in industrialised countries, and an increasing number of people, with an increasing median age, travel from areas of low HAV endemicity to high endemicity, pre-travel vaccination is warranted. Vaccination of the elderly against HAV, however, may be associated with reduced seroprotection, since the immune response decreases with age. Studies with monovalent hepatitis A vaccine or combined hepatitis A and B vaccine show good efficacy in adults in general. Few studies have assessed the immune response in older adults. The only prospective study with monovalent hepatitis A vaccine in the elderly showed a reduced seroprotection of approximately 65% after a single primary dose in subjects over the age of 50 years, while seroprotection was 98% in this age group after receiving a booster dose. The only prospective study with combined hepatitis A and B vaccine in younger subjects or older than 40 years showed similar seroprotection (99-100%) against HAV compared to a monovalent vaccine after receiving three doses. As data on seroprotection for HAV in the elderly are limited, further studies are needed to elucidate how optimal protection in the elderly can be achieved. In the mean time, based on the available data, the suggestion is made to screen elderly travellers to areas endemic for HAV for the presence of naturally acquired immunity, and, if found susceptible, be immunised well in advance of their trip, to allow time for post-vaccination antibody testing and/or administration of a second dose of the vaccine.

Climate and human impact during the past 2000 years as recorded in the Lagunas de Yala, Jujuy, northwestern Argentina

210Pb, 137Cs and 14C dated sediments of two late Holocene landslide lakes in the Provincial Park Lagunas de Yala (Laguna Rodeo, Laguna Comedero, 24°06′S, 65°30′W, 2100 m asl, northwestern Argentina) reveal a high-resolution multi-proxy data set of climate change and human impact for the past ca. 2000 years. Comparison of the lake sediment data set for the 20th century (sediment mass accumulation rates MARs, pollen spectra, nutrient and charcoal fluxes) with independent dendroecological data from the catchment (fire scars, tree growth) and long regional precipitation series (from 1934 onwards) show that (1) the lake sediment data set is internally highly consistent and compares well with independent data sets, (2) the chronology of the sediment is reliable, (3) large fires (1940s, 1983/1984–1989) as documented in the local fire scar frequency are recorded in the charcoal flux to the lake sediments and coincide with low wet-season precipitation rates (e.g., 1940s, 1983/1984) and/or high interannual precipitation variability (late 1940s), and (4) the regional increase in precipitation after 1970 is recorded in an increase in the MARs (L. Rodeo from 100 to 390 mg cm−2 yr−1) and in an increase in fern spores reflecting wet vegetation. The most significant change in MARs and nutrient fluxes (Corg and P) of the past 2000 years is observed with the transition from the Inca Empire to the Spanish Conquest around 1600 AD. Compared with the pre-17th century conditions, MARs increased by a factor of ca. 5 to >8 (to 800 +130, −280 mg cm−2 yr−1), PO4 fluxes increased by a factor of 7, and Corg fluxes by a factor of 10.5 for the time between 1640 and 1930 AD. 17th to 19th century MARs and nutrient fluxes also exceed 20th century values. Excess Pb deposition as indicated by a significant increase in Pb/Zr and Pb/Rb ratios in the sediments after the 1950s coincides with a rapid expansion of the regional mining industry. Excess Pb is interpreted as atmospheric deposition and direct human impact due to Pb smelting.

Comparison of intraarterial and intravenous thrombolysis for ischemic stroke with hyperdense middle cerebral artery sign

BACKGROUND AND PURPOSE: It is unclear whether intraarterial (IAT) or intravenous (IVT) thrombolysis is more effective for ischemic stroke with hyperdense middle cerebral artery sign (HMCAS) on computed tomography (CT). The aim of this study was to compare IAT and IVT in stroke patients with HMCAS. METHODS: Comparison of data from 2 stroke units with similar management of stroke associated with HMCAS, except that 1 unit performed IAT with urokinase and the other IVT with plasminogen activator. Time to treatment was up to 6 hours for IAT and up to 3 hours for IVT. Outcome was measured by mortality and the modified Rankin Scale (mRS), dichotomized at 3 months into favorable (mRS 0 to 2) and unfavorable (mRS 3 to 6). RESULTS: One hundred twelve patients exhibited a HMCAS, 55 of 268 patients treated with IAT and 57 of 249 patients who underwent IVT. Stroke severity at baseline and patient age were similar in both groups. Mean time to treatment was longer in the IAT group (244+/-63 minutes) than in the IVT group (156+/-21 minutes; P=0.0001). However, favorable outcome was more frequent after IAT (n=29, 53%) than after IVT (n=13, 23%; P=0.001), and mortality was lower after IAT (n=4, 7%) than after IVT (n=13, 23%; P=0.022). After multiple regression analysis IAT was associated with a more favorable outcome than IVT (P=0.003) but similar mortality (P=0.192). CONCLUSIONS: In this observational study intraarterial thrombolysis was more beneficial than IVT in the specific group of stroke patients presenting with HMCAS on CT, even though IAT was started later. Our results indicate that a randomized trial comparing both thrombolytic treatments in patients with middle cerebral artery occlusion is warranted.

Ultrasound diagnosis of spontaneous carotid dissection with isolated Horner syndrome

BACKGROUND AND PURPOSE: Isolated Horner syndrome without associated cranial nerve palsies or ischemic symptoms is an important presentation of spontaneous internal carotid artery dissection (sICAD). Ultrasound is often used as a screening method in these patients because cervical MRI is not always available on an emergency basis. Current knowledge on ultrasound findings in patients with sICAD presenting with isolated Horner syndrome is limited. METHODS: Patients were recruited from prospective cervical artery dissection databases of 3 tertiary care centers. Diagnosis of sICAD was confirmed by cervical MRI and MR angiography or digital subtraction angiography in all patients. Data on Doppler sonography and color duplex sonography examinations performed within 30 days of symptom onset were analyzed. RESULTS: We identified 88 patients with Horner syndrome as the only sign of sICAD. Initial ultrasound examination was performed in 72 patients after a mean time interval from symptom onset to examination of 11 (SD 8) days. The overall frequency of false-negative ultrasound findings was 31% (22 of 72 patients). It showed stenosis >or=80% or occlusion in 34 (47%) patients, and stenosis

Is pseudophakia a risk factor for neovascular age-related macular degeneration?

PURPOSE: To examine the possible association between pseudophakia and neovascular age-related macular degeneration (AMD). METHODS: Reports of all patients undergoing fluorescein angiography in the authors' department over a 6-year period were retrospectively reviewed. Four hundred ninety-nine patients with recent onset of neovascular AMD in one eye and early age-related maculopathy (ARM) in the fellow eye were included in the study. Lens status (phakic or pseudophakic) in both eyes at the time of onset of neovascular AMD and the time between cataract surgeries (if performed) and onset of neovascular AMD were determined. RESULTS: There was no significant difference in lens status between eyes with neovascular AMD and fellow eyes with early ARM (115/499 [23.0%] vs. 112/499 [22.4%] pseudophakic; P = 0.88, odds ratio 1.035, 95% CI 0.770-1.391). Subgroup analysis revealed no difference between the groups with large drusen, small drusen, or pigmentary changes only (respectively, 20.3% vs. 19.6% pseudophakic, P = 0.92; 20.5% vs. 23.3% pseudophakic, P = 0.84; 33.3% vs. 31.7% pseudophakic, P = 1.0). Pseudophakic eyes with neovascular AMD had not been pseudophakic for a significantly longer period at the time of onset of neovascular AMD than their pseudophakic fellow eyes at the same time point (225.9 +/- 170.4 vs. 209.9 +/- 158.2 weeks, P = 0.27). CONCLUSIONS: The results do not support the hypothesis that pseudophakia is a major risk factor for the development of neovascular AMD.

Dosimetric impact of geometric errors due to respiratory motion prediction on dynamic multileaf collimator-based four-dimensional radiation delivery

The synchronization of dynamic multileaf collimator (DMLC) response with respiratory motion is critical to ensure the accuracy of DMLC-based four dimensional (4D) radiation delivery. In practice, however, a finite time delay (response time) between the acquisition of tumor position and multileaf collimator response necessitates predictive models of respiratory tumor motion to synchronize radiation delivery. Predicting a complex process such as respiratory motion introduces geometric errors, which have been reported in several publications. However, the dosimetric effect of such errors on 4D radiation delivery has not yet been investigated. Thus, our aim in this work was to quantify the dosimetric effects of geometric error due to prediction under several different conditions. Conformal and intensity modulated radiation therapy (IMRT) plans for a lung patient were generated for anterior-posterior/posterior-anterior (AP/PA) beam arrangements at 6 and 18 MV energies to provide planned dose distributions. Respiratory motion data was obtained from 60 diaphragm-motion fluoroscopy recordings from five patients. A linear adaptive filter was employed to predict the tumor position. The geometric error of prediction was defined as the absolute difference between predicted and actual positions at each diaphragm position. Distributions of geometric error of prediction were obtained for all of the respiratory motion data. Planned dose distributions were then convolved with distributions for the geometric error of prediction to obtain convolved dose distributions. The dosimetric effect of such geometric errors was determined as a function of several variables: response time (0-0.6 s), beam energy (6/18 MV), treatment delivery (3D/4D), treatment type (conformal/IMRT), beam direction (AP/PA), and breathing training type (free breathing/audio instruction/visual feedback). Dose difference and distance-to-agreement analysis was employed to quantify results. Based on our data, the dosimetric impact of prediction (a) increased with response time, (b) was larger for 3D radiation therapy as compared with 4D radiation therapy, (c) was relatively insensitive to change in beam energy and beam direction, (d) was greater for IMRT distributions as compared with conformal distributions, (e) was smaller than the dosimetric impact of latency, and (f) was greatest for respiration motion with audio instructions, followed by visual feedback and free breathing. Geometric errors of prediction that occur during 4D radiation delivery introduce dosimetric errors that are dependent on several factors, such as response time, treatment-delivery type, and beam energy. Even for relatively small response times of 0.6 s into the future, dosimetric errors due to prediction could approach delivery errors when respiratory motion is not accounted for at all. To reduce the dosimetric impact, better predictive models and/or shorter response times are required.

Takotsubo cardiomyopathy or transient left ventricular apical ballooning syndrome: A systematic review

BACKGROUND: Transient left ventricular apical ballooning syndrome (TLVABS) is an acute cardiac syndrome mimicking ST-segment elevation myocardial infarction characterized by transient wall-motion abnormalities involving apical and mid-portions of the left ventricle in the absence of significant obstructive coronary disease. METHODS: Searching the MEDLINE database 28 case series met the eligibility criteria and were summarized in a narrative synthesis of the demographic characteristics, clinical features and pathophysiological mechanisms. RESULTS: TLVABS is observed in 0.7-2.5% of patients with suspected ACS, affects women in 90.7% (95% CI: 88.2-93.2%) with a mean age ranging from 62 to 76 years and most commonly presents with chest pain (83.4%, 95% CI: 80.0-86.7%) and dyspnea (20.4%, 95% CI: 16.3-24.5%) following an emotionally or physically stressful event. ECG on admission shows ST-segment elevations in 71.1% (95% CI: 67.2-75.1%) and is accompanied by usually mild elevations of Troponins in 85.0% (95% CI: 80.8-89.1%). Despite dramatic clinical presentation and substantial risk of heart failure, cardiogenic shock and arrhythmias, LVEF improved from 20-49.9% to 59-76% within a mean time of 7-37 days with an in-hospital mortality rate of 1.7% (95% CI: 0.5-2.8%), complete recovery in 95.9% (95% CI: 93.8-98.1%) and rare recurrence. The underlying etiology is thought to be based on an exaggerated sympathetic stimulation. CONCLUSION: TLVABS is a considerable differential diagnosis in ACS, especially in postmenopausal women with a preceding stressful event. Data on longterm follow-up is pending and further studies will be necessary to clarify the etiology and reach consensus in acute and longterm management of TLVABS.

Early implant placement with simultaneous guided bone regeneration following single-tooth extraction in the esthetic zone: a cross-sectional, retrospective study in 45 subjects with a 2- to 4-year follow-up

BACKGROUND: The concept of early implant placement is a treatment option in postextraction sites of single teeth in the anterior maxilla. Implant placement is performed after a soft tissue healing period of 4 to 8 weeks. Implant placement in a correct three-dimensional position is combined with a simultaneous guided bone regeneration procedure to rebuild esthetic facial hard and soft tissue contours. METHODS: In this retrospective, cross-sectional study, 45 patients with an implant-borne single crown in function for 2 to 4 years were recalled for examination. Clinical and radiologic parameters, routinely used in implant studies, were assessed. RESULTS: All 45 implants were clinically successful according to strict success criteria. The implants demonstrated ankylotic stability without signs of a peri-implant infection. The peri-implant soft tissues were clinically healthy as indicated by low mean plaque (0.42) and sulcus bleeding index (0.51) values. None of the implants revealed a mucosal recession on the facial aspect as confirmed by a clearly submucosal position of all implant shoulders. The mean distance from the mucosal margin to the implant shoulder was -1.93 mm on the facial aspect. The periapical radiographs showed stable peri-implant bone levels, with a mean distance between the implant shoulder and the first bone-implant contact of 2.18 mm. CONCLUSIONS: This retrospective study demonstrated successful treatment outcomes for all 45 implants examined. The mid-term follow-up of 2 to 4 years also showed that the risk for mucosal recession was low with this treatment concept. Prospective clinical studies are required to confirm these encouraging results.