Volumetric Misfit in CAD/CAM and Cast Implant Frameworks: A University Laboratory Study

Purpose: To compare the volumetric misfit between implant restorative platforms of implants and implant frameworks manufactured with two different technologies. One set of implant frameworks was made with a CAD/CAM protocol and a tactile probe; the second protocol consisted of frameworks made with the lost‐wax technique and conventional casting technology. Materials and Methods: In this laboratory study, an acrylic resin model with five “inter‐foraminal” implants was used as the “patient” model. Implant level impressions were made, and 10 definitive master casts were fabricated. The casts were verified using an index made on the patient model. Five cast high palladium noble alloy and five CAD/CAM titanium alloy frameworks were fabricated. The patient's implants and the frameworks’ implant restorative platforms were scanned with a tactile probe, and the data were digitized. The digitized implant restorative platforms of the frameworks were fit onto the patient's digitized implants via a software program, in a process called “lofting.” This computerized procedure simulated a 1‐screw test; the process was performed on both sides. The volumetric misfit between the implant restorative platforms of the frameworks and the patient's implants were measured. A Welch's t‐test was used to determine significant differences (p < 0.05) between the misfit of the two technologies. Wilcoxon Signed‐Rank tests were used to evaluate differences between the right and left sides. Results: On average, the volumetric misfit of the CAD/CAM frameworks was 1.8 mm³ less than the volumetric misfit of the cast alloy frameworks (p < 0.05). The Wilcoxon Signed‐Rank tests showed no significant differences between the right and left sides within both systems (p > 0.05). Conclusions: The scanning technology and computer software program used in this study demonstrated that the CAD/CAM implant frameworks had statistically significantly less volumetric misfit when compared with the cast implant frameworks. There were no significant differences between the right and left 1‐screw tests within the same type of frameworks.     

Native nephrectomy for autosomal dominant polycystic kidney disease: before or after kidney transplantation?

Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? The indications and timing of native nephrectomy in patients with autosomal dominant polycystic kidney disease (ADPKD) is controversial, especially for those undergoing renal transplantation. Post‐transplant unilateral native nephrectomy appears to be the preferred intervention compared to pre‐transplant native nephrectomy. There seems to be substantial additive risk to bilateral over unilateral nephrectomy, especially prior to transplantation. Pre‐transplant native nephrectomy should only be carried out when there are clear indications such as massive size preventing allograft placement, severe pain, early satiety, recurrent bleeding and infections, or suspected malignancy.

OBJECTIVE

To analyse indications, timing and outcomes of native nephrectomy in autosomal dominant polycystic kidney disease (ADPKD) patients listed for kidney transplantation.

PATIENTS AND METHODS

A retrospective analysis of all ADPKD patients who had a native nephrectomy prior to or following transplantation between January 2003 and December 2009 at a single centre, including those undergoing the sandwich technique (removal of the most severely affected native kidney prior to transplantation, and the other afterwards), was undertaken.

RESULTS

There were 35 individuals in our cohort (M : F = 16 : 19), with a median age of 51.5 years (range 43–65). Twenty patients were in the pre‐transplant nephrectomy group, 12 in the post‐transplant group, and three underwent the sandwich technique. Indications for nephrectomy varied but were most commonly pain/discomfort, space for transplantation, ongoing haematuria, recurrent infections, and gastrointestinal pressure symptoms (early satiety). Seven individuals in the pre‐transplant group and three in the post‐transplant group required critical care admission after nephrectomy. Transient renal graft dysfunction occurred in two post‐transplant bilateral nephrectomy patients. Two patients in the bilateral nephrectomy pre‐transplant group and one in the bilateral nephrectomy post‐transplant group died in the immediate post‐operative period. No complications were noted in the sandwich technique group.

CONCLUSION

Native nephrectomy in ADPKD is a major undertaking associated with significant morbidity especially in the pre‐transplant group. Post‐transplant unilateral nephrectomy appears to be the safest approach with fewest complications.     

Hereditary thrombophilia in ethnic Omani patients

Hereditary thrombophilias are a group of inherited conditions that predispose to thrombosis. Mutations like factor V Leiden, prothrombin gene variant 20210A, and hereditary hyperhomocysteinemia are associated with an increased risk for thromboembolism as compared to mutations in natural inhibitors of coagulation. There is also evidence that multiple defects co-exists in persons with a tendency for thrombosis. We studied prothrombotic determinants, namely protein C, protein S, and AT along with factor V Leiden (1691G-->A), prothrombin gene mutation (20210G-->A), CBS 844ins68 mutation, and MTHFR mutation (677C-->T) in consecutive ethnic Omani patients with first episode of a thrombophilic event, namely, deep vein thrombosis (DVT), and/or pulmonary embolism (PE) or thrombosis at an unusual site. Fasting plasma homocysteine was also analyzed. Factor V Leiden and the prothrombin gene mutation were not seen in any patient nor in any control subject studied. The thermolabile MTHFR mutation (677C-->T) was present in 14 patients (35.89%) whereas the CBS 844ins68 mutation was documented in 6 patients (15.38%); 3 patients were common in both groups. Six patients had low protein C (15.38%), two patients had low protein S (5.12%), but none had low AT levels. Interestingly, one patient had triple abnormality, namely, PC deficiency with both CBS 844ins68 mutation as well as the MTHFR mutation (677C-->T) whereas another two patients had the latter two mutations together. This data set, although small, reflects the importance of multiple screening strategies. The yield appears high, emphasizing the referral pattern to a tertiary health center. Of these patients, 43.58% had either or both the hyperhomocysteinemic mutations studied, whereas in 38.46% of these patients, no underlying cause for thrombophilia could be documented.     

Monitoring with EEG entropy decreases propofol requirement and maintains cardiovascular stability during induction of anaesthesia in elderly patients

BACKGROUND AND OBJECTIVES: Electroencephalographic entropy is used to measure the degree of brain hypnosis and anaesthesia depth. Two parameters are displayed in the monitor, state entropy (SE) and response entropy (RE). Ageing leads to reduction in liver mass as well as hepatic blood flow, which decreases clearance of propofol and increases the risk of cardiovascular adverse effects. The aim of this study is to demonstrate the effect of electroencephalographic entropy on propofol requirement and haemodynamic parameters during induction of anaesthesia in elderly patients. METHODS: We studied 72 elderly patients. Standard monitoring was performed for all patients together with entropy monitor. Patients were allocated randomly either to the control group, which were given the recommended induction dose of propofol, or to the entropy group which was induced with propofol based on entropy reading where the end-point was SE 50 and SE-RE difference less than 10. Propofol induction doses and haemodynamic changes were recorded. Anaesthesia was maintained using sevoflurane and O2 air mixture. RESULTS: After induction of anaesthesia, the systolic, diastolic, mean arterial pressure, RE and SE were significantly lower in the control group (P value < 0.05). Total dose of propofol and the dose kg-1 were significantly reduced by 37.1% and 31.8%, respectively, in the entropy group (P value < 0.01). CONCLUSION: The use of electroencephalographic entropy during induction of anaesthesia in elderly patients reduces propofol requirements and maintains cardiovascular stability.     

A PET imaging study of 5-HT(1A) receptors in cat brain after acute and chronic fluoxetine treatment

Immuno-electron microscopic and beta-microprobe studies have demonstrated that the internalization of serotonin 5-HT(1A) autoreceptors, after acute treatment with the selective 5-HT(1A) receptor agonist 8-OH-DPAT or with the specific serotonin reuptake inhibitor (SSRI) fluoxetine, is associated with a marked decrease in the in vivo binding of [(18)F]MPPF in the nucleus raphe dorsalis (NRD) of rat. To determine whether this event might be amenable to brain imaging, the present [(18)F]MPPF positron emission tomographic (PET) study was carried out in anesthetized cats given or not a single dose (5 mg/kg, i.v.) or chronically treated with fluoxetine (5 mg/kg, s.c. for 21 days). Compared to control, [(18)F]MPPF binding potential was considerably (and visibly) decreased in the cat NRD after acute fluoxetine treatment, while it remained unchanged in other brain regions. Unexpectedly, after chronic fluoxetine treatment, [(18)F]MPPF binding potential was not affected in any brain region. In parallel immuno-electron microscopic experiments carried out in rat, the density of 5-HT(1A) autoreceptors on the plasma membrane of NRD dendrites was comparable to control after chronic fluoxetine treatment. If the decrease in [(18)F]MPPF binding at the onset of SSRI treatment was detectable by PET imaging, it could potentially serve as a biological index of efficacy.     

Persistence in Staphylococcus aureus bacteremia: incidence, characteristics of patients and outcome

Staphylococcus aureus bacteremia often persists. The reasons for persistence and its outcome are poorly defined. We conducted a prospective-observational study among 245 consecutive S. aureus (MRSA: n=125; MSSA: n=120) bacteremias (>or=1 positive blood cultures (BC)) among 234 adults (18-103-y-old; median=59 y) hospitalized during 1 January 2002-31 December 2002 at a 600-bed teaching hospital. Measurements included bacteremia duration, complication-rate (metastatic infection, relapse or attributable mortality) and outcome. Bacteremia duration was measured based on follow-up BC among 193 patients and estimated based on symptoms resolution in the rest. Measured (1-59 d; median=2) and estimated (median=1 d) duration correlated (r=0.885) though positive follow-up BC was often detected without fever (57/105 patients, 54.3%). Persistence (defined as bacteremia for >or=3 d) was noted in 84 cases (38.4%). Complication-rate increased steadily with bacteremia duration (6.6%, 24.0% and 37.7% in bacteremia for 1-2, 3 and >or=4 d, respectively; p=0.05). Cox regression analysis revealed that bacteremia duration correlated positively with endovascular sources (p=0.006), vancomycin treatment (p=0.016), cardiovascular prosthesis (p=0.025), metastatic infections (p=0.025) and diabetes (p=0.038). It is concluded that persistent bacteremia is a feature of S. aureus infection, irrespective of oxacillin susceptibility, associated with worse outcome. Risk factors include endovascular sources, cardiovascular prosthesis, metastatic infections, vancomycin treatment and diabetes. Patients at risk may benefit from novel treatment strategies.     

Pancreaticopleural Fistula: Report of Two Cases and Review of the Literature

Pancreaticopleural fistulas are a rare complication of pancreatitis. We report two cases from our institution and review 37 cases of pancreaticopleural fistulas identified in the literature. Endoscopic retrograde cholangiopancreatography was more sensitive compared to computed tomography in demonstrating pancreaticopleural fistulas (79% versus 43%, respectively). Medical therapy with total parenteral nutrition, octreotide, and/or chest tube placement was successful in resolving the pancreaticopleural fistula in up to 33% of cases. None of the patients who underwent pancreatic duct stent and/or nasopancreatic drain placement required surgical intervention. Endoscopic retrograde cholangiopancreatography is the initial test of choice when the diagnosis of pancreaticopleural fistula is suspected. Early endoscopic intervention with pancreatic duct stent placement is recommended given its high success rate in fistula closure. Medical therapies are useful adjuncts to endoscopic therapy, but rarely result in pancreaticopleural fistula closure alone. Surgical interventions should only be considered after failure of endoscopic and medical therapies.