Influence of residual alveolar bone height on osseointegration of implants in the maxilla: a pilot study

Aims/Background: For sinus floor augmentation and simultaneous implant placement, a minimum of 5 mm of residual bone height has been recommended empirically. This study was designed to test this assumption in an experimental animal trial. Material and methods: In eight mini pigs, three premolars and two molars were removed on one side of the maxilla. Three months later, the animals were assigned to four groups of two animals each. A cavity was created at the base of the alveolar process so that the residual bone height was reduced to 2, 4, 6 and 8 mm, respectively. Six implants were installed and an inlay augmentation procedure was carried out using a particulated iliac bone graft. Implants were loaded with fixed provisional restorations after a healing period of 6 months. The animals were sacrificed after 6 months of functional loading. Histologic specimens were prepared and histomorphometric analysis was performed [bone‐to‐implant contact (BIC) ratio, interthread bone area, peri‐implant bone area, crestal bone resorption (CBR)]. Results: Two implants were lost during follow‐up and fibrous encapsulation was detected in one additional implant. All failures occurred in one animal with a residual alveolar height of 2 mm. On the buccal aspect, BIC turned out to be significantly higher for 6 mm when compared with 2/4 mm (75.8 ± 26.1 vs. 58 ± 23.2/53.9 ± 22.8; P<0.05), while on the palatal aspect, BIC was significantly higher for 6/8 mm when compared with 2/4 mm (80 ± 17.8/78.9 ± 10.3 vs. 55.8 ± 26.5/55.6 ± 21.3; P<0.05). For an alveolar height of 8 mm, CBR tended to be significantly lower than for bone heights of 2/4 mm (3.8 ± 2.3 vs. 5.3 ± 2.6/5.8 ± 3.9; P<0.05). Correlation analysis revealed a significant association of BIC and interthread bone area as well as a negative association to CBR on the palatal aspect. Conclusion: The results of the present study show that the combination of maxillary inlay grafting and simultaneous implant placement does not hinder osseous integration even though the alveolar crest has been reduced to a residual height of 4 mm and below. However, according to histomorphometry, the highest predictability is gained in sites with residual bone heights of 6 and 8 mm.     

Vascular mapping of head and neck: computed tomography angiography versus digital subtraction angiography.

PURPOSE: The aim of the study was to compare multislice computed tomography angiography (MSCTA) to digital subtraction angiography (DSA) for vascular mapping of the head and neck. PATIENTS AND METHODS: In 50 patients who were scheduled for microvascular reconstruction of the mandible with osteomyocutaneous flaps, MSCTA was carried out before surgery. DSA served as the method of reference. Selective common carotid angiograms were acquired in 2 projections for both sides of the neck. A 64-slice spiral computed tomography (CT) was carried out with a dual-phase protocol, using the arterial phase images for 3-dimensional CTA reconstruction. Volume rendering was used to visualize MSCTA data. RESULTS: No adverse reactions or complications occurred during or after the procedures. All CT angiograms were of diagnostic quality. No statistically significant differences between MSCTA and DSA were found for the detection of branches of the external carotid artery that are relevant host vessels for microsurgery neither in the group of 26 patients who had not had surgical treatment before (P = .687), nor in the group of 24 patients who were affected by either a tumor recurrence or an infected osteoradionecrosis (P = .508). CONCLUSION: MSCTA proved to be a reliable alternative to DSA in vascular mapping for planning of microvascular reconstruction of the mandible.     

Implantable defibrillator therapy in Naxos disease

Naxos disease is a unique form of right ventricular cardiomyopathy with a high prevalence of malignant ventricular arrhythmias, including sudden cardiac death. As a hereditary systemic disease confined to a small island, it has been closely studied over the last 15 years. The implantation of an automatic defibrillator provides an alternative form of antiarrhythmic management to improve life expectancy in these high risk cardiac patients. We present the first two Naxos disease patients with malignant ventricular arrhythmias who had defibrillator implantation.     

Updates and Critical Insights on Glissonian Approach in Liver Surgery

Recent advances in surgical techniques have broadened the indications of surgical management of liver malignancies. Intraoperative bleeding is one of the known predictors of postoperative outcomes following liver surgery, signifying the importance of vascular control during liver resection. Furthermore, preservation of future liver remnant plays a critical role in prevention of post-hepatectomy liver failure as one of the main causes of postoperative morbidity and mortality. Glissonian approach liver resection offers an effective method for vascular inflow control while protecting future liver remnant from ischemia-reperfusion injury. Several studies have demonstrated the feasibility of Glisson’s pedicle resection technique in modern liver surgery with an acceptable safety profile. Moreover, with increasing popularity of minimally invasive surgery, laparoscopic liver resection via Glissonian approach has been shown to be superior to standard laparoscopic hepatectomy. Herein, we systematically review the role of Glissonian approach hepatectomy in current practice of liver surgery, highlighting its advantages and disadvantaged over other methods of vascular control.     

Characterization of “γ-Eye”: a Low-Cost Benchtop Mouse-Sized Gamma Camera for Dynamic and Static Imaging Studies

Purpose

Several preclinical imaging systems are commercially available, but their purchase and maintenance costs make them unaffordable for the majority of small- and medium-sized groups. Taking into account the needs of average users, we developed “γ-eye”, a mouse-sized, benchtop γ-camera suitable for in vivo scintigraphic imaging.

Procedures

The γ-eye is based on two position-sensitive photomultiplier tubes, coupled to a CsI(Na) pixelated scintillator and a low-energy lead collimator with parallel hexagonal holes.

Results

The spatial resolution of the system is 2 mm at 0 mm. The energy resolution is 26 % at 140 keV and the maximum recorded sensitivity 210 cps/MBq. The system was evaluated in a proof-of-concept animal study, using three different clinical Tc-99m-labeled radiopharmaceuticals. Phantom and animal studies demonstrate its ability to provide semiquantitative results even for short scans.

Conclusions

Systems’ performance, dimensions, and cost make γ-eye a unique solution for efficient whole-body mouse nuclear imaging.

     

Hepatitis B virus DNA-positive, hepatitis B surface antigen-negative blood donations intercepted by anti-hepatitis B core antigen testing: the Canadian Blood Services experience

BACKGROUND: The benefit of introducing anti-hepatitis B core antigen (HBc) screening for intercepting potentially infectious donations missed by hepatitis B surface antigen (HBsAg) screening in Canada was studied. STUDY DESIGN AND METHODS: Anti-HBc testing of all donations was implemented in April 2005, along with antibody to hepatitis B surface antigen (anti-HBs) and hepatitis B virus (HBV) DNA supplemental testing of anti-HBc repeat-reactive, HBsAg-negative donations. The proportion of potentially infectious donations intercepted by anti-HBc over the initial 18 months of testing was calculated based on three assumptions relating infectivity of HBV DNA-positive units to anti-HBs levels. Lookback was conducted for all DNA-positive donations. RESULTS: Of 493,344 donors, 5,585 (1.13%) were repeat-reactive for the presence of anti-HBc, with 29 (0.52%) being HBV DNA-positive and HBsAg-negative. The proportion of potentially infectious donations intercepted by anti-HBc screening was 1 in 17,800 if all HBV DNA-positive donations were infectious, 1 in 26,900 if infectivity was limited to donations with an anti-HBs level of not more than 100 mIU per mL, and 1 in 69,300 if only donations with undetectable anti-HBs were infectious. For 279 components in the lookback study, no traced recipients were HBsAg-positive and 7 recipients were anti-HBc-reactive in association with 4 donors, 3 of whom had an anti-HBs level of more than 100 mIU per mL and 1 of whom had a level of 61 mIU per mL. CONCLUSION: Implementation of anti-HBc screening reduced the risk of transfusing potentially infectious units by at least as much as had been expected based on the literature. The lookback did not provide proof of transfusion transmission of HBV from HBV DNA-positive, anti-HBc-reactive, HBsAg-negative donors but it did not establish lack of transmission either.     

Altered kallikrein 7 and 10 concentrations in cerebrospinal fluid of patients with Alzheimer's disease and frontotemporal dementia

BACKGROUND: The role of various proteases in the pathogenesis of Alzheimer's disease is well documented. Recently, many members of the human tissue kallikrein family, a group of 15 secreted serine proteases, were found to be highly expressed in the central nervous system (CNS). Some of these enzymes can be measured in cerebrospinal fluid (CSF) by using ELISA-type methodologies. METHODS: We quantified various kallikreins in CSF of 20 patients with Alzheimer's disease (AD), 16 patients with frontotemporal dementia (FTD), and 15 controls. We then correlated the levels of various kallikreins with presence of AD or FTD. Among all kallikreins measured, detectable levels in CSF were identified for kallikreins hK6, hK7, and hK10. Other tested kallikreins (hK5, hK8, hK11, and hK13) were unmeasurable. The most notable differences between kallikrein levels in CSF and the three groups of subjects were seen between controls and FTD patients for hK6 (decrease in FTD; P = 0.017), controls and FTD patients for hK7 (decrease in FTD; P < 0.001), and controls and AD patients for hK7 (decrease in AD; P = 0.019). In addition, significant differences were seen between FTD patients or control subjects and patients with AD patients for hK10 (increase in AD; P < 0.02). Approximately half of the AD patients had CSF hK10 levels that were higher than all patients with FTD except one and all control subjects except two. Various kallikrein concentrations in CSF were correlated, the strongest correlation seen between hK6 and hK7 (r(s) = 0.58). We also observed a statistically significant association between decreasing hK7 concentration in CSF and possession of one or two ApoE4 alleles (P = 0.014). CONCLUSIONS: We demonstrate for the first time significant alterations of hK6, hK7, and hK10 concentration in CSF of patients with AD and FTD. Notably, all three kallikreins (hK6, hK7, and hK10) are decreased in CSF of FTD patients and hK10 is increased in CSF of AD patients, in comparison to control subjects. The possible connection between these enzymes and the pathogenesis and progression of AD and FTD needs to be further investigated.