A suggested protocol to increase the accuracy of prosthetic phases in case of full-arch model-free fully guided computer-aided implant placement and immediate loading.

PURPOSE: The accuracy of fully digital model-free surgical and prosthetic procedures depends on the cumulative effect and interaction of all errors gathered along the entire workflow process. In the present case series, a technique is described that increases the accuracy in the transition from the surgical to the prosthetic phase to reduce the risk of developing prosthetic complications in the case of immediate loading protocols. METHODS: Overall, 86 dental implants were placed and immediately loaded with definitive prostheses in 11 edentulous patients following computer-guided implant surgery according to a fully digital model-free workflow. The same reference template used to anchor the surgical stent during computer-aided implant placement was used to guide the insertion of the definitive abutments and to seat in the correct position the final screw-retained implant-supported fixed restoration. The template used during all surgical and prosthetic procedures, which served as a stable and reproducible connection between the digital and surgical environments, was finally removed. RESULTS: Healing proceeded uneventfully in all subjects. The implant survival and success rates were 100% over a minimum follow-up period of 1 year from the prosthetic loading. No biological or prosthetic complications were clinically and radiographically observed up to the last follow-up recall. CONCLUSION: The use of a reference template used to transfer the digital project to the surgical field increased the accuracy and the integration of the surgical and prosthetic phases during the entire workflow.

Reduction in urea distribution volume over time in clinically stable dialysis patients.

We have previously shown that, assuming urea distribution volume (V) remains constant for 1 month, ionic dialysance (ID) allows the dialysis dose to be calculated without the need for blood sampling. The aim of this multicenter study was to verify whether the assumption of a constant V can be extended to 1 year. In clinically stable patients receiving thrice-weekly hemodialysis at 13 dialysis centers, V and Kt/V were assessed during three dialysis sessions at baseline and 1 year later using ID as dialyzer urea clearance and the single-pool urea kinetic model. Baseline albumin, hemoglobin, and C reactive protein were prespecified covariates for predicting the change in V over time. Of the 52 enrolled patients, 40 (25 males; age 63.0+/-13.5 years) completed the study. Baseline end-dialysis body weight (62.4+/-13.7 kg) showed a non-significant 1% reduction during follow-up (-0.6+/-2.8 kg; P=0.175), whereas V significantly decreased from 29.0+/-6.8 to 27.4+/-6.0 l (-1.6+/-3.0 l or 4.5%; P=0.002). The reduction in V was greater when baseline albumin was lower (P=0.001) and baseline V was higher (P=0.005). The single-pool K(t)/V calculated using baseline V underestimated the actual value by 0.07+/-0.16 (P=0.008). The slight underestimate of Kt/V during follow-up suggests that annual V evaluations may be sufficient for dialysis dose quantification as the only risk is underestimating the actually delivered dialysis dose. However, the relationship between baseline albumin and the reduction in V over time may have nutritional value, and suggests more frequent V evaluations.

[A good vascular access allows an effective treatment]. / Un buon accesso vascolare permette un trattamento efficace.

Vascular access (VA) for dialysis is defined as the 'Achilles heel', but also the 'Cinderella' of dialysis, indicating the poor consideration of the problem whether in the surgical environment, or in incomprehensible way in that nephrologic. It can only aspire to the definition 'Fundamental detail'. However, presupposed effective dialysis is a blood flow rate of 300-350 mL/min. Good VA must be easy to prepare, long lasting, free from complications, and aesthetically acceptable and economical. The arteriovenous fistula (AVF) of Cimino and Brescia, from 1966, represents the gold standard and the model of comparison for other systems, more technologically advanced. It must be programmed with an adapted margin (1-2 months) to allow maturation and access certainty for the first puncture, and never carried out sooner than 14 days from the operation. It is known from hemodynamic studies that the good functional flow of the new fistula can already regain 400-500 ml/min in the first week, with cardiological implications like the increase in cardiac throw, in ejection fraction and in the cardiac index. Health workers, patients and dialysis staff must follow a continuous educational program to protect the VA and avoid 'routine and absent-minded management', a basis for its premature failure. The nephrologist must take the responsibility upon himself not to carry out 'medical malpractice'. In the Dialysis Center of Mantova, the VA 'road map' previews all patients (young and old, affections from mono or pluropathology), first the fistula to the wrist, then the cephalic proximal. It follows the basilic vein transposition, the vascular graft to the arm or to the groin, as an alternative to peritoneal dialysis. The permanent central venous catheter (CVCp) is the last choice in patients with reduced life expectancy, heart failure, neoplastic patients with vascular patrimony destroyed by chemotherapy and ischemic lesions produced by the fistula. There were 180 afferent prevailing patients at the Mantova Dialysis Center . The natural fistula rate was 91%, grafts 7% and CVCps 2%. Between 2000 and 31 March 2004 we prepared 367 VAs. Average patient age was 65 yrs, range 20-90 yrs; 59% male and 41% female. Eighty-eight percent of operations were performed by the nephrologist (distal fistula, rescue and cephalic proximal) and 12% by the vascular surgeon (basilic vein transposition, graft in PTFE stretch to the arm and to the groin and permanent catheter in the jugular vein). The fistula with native veins was the better solution, the graft must be prepared after the exhaustion of natural possibilities, and the CVCp, for serious complications (inadequate flow and infections), must be the last alternative.

[Dosimetric study in vivo, using a computer, of Co-60 irradiation of patients with breast prosthesis made of silicone]. / Studio dosimetrico in vivo e a calcolatore di irradiazioni con 60Co di protesi mammarie in silicone.

This work studies the dose distribution through the chest wall in radiation therapy after mammary reconstruction with silicone prostheses. TLD experimental dosimetry has been done on patient with silicone prostheses, on patient without prostheses and on Alderson phantom. Various conditions of treatment have been theorically simulated on a computer. At least authors show the results evaluating the dose distribution through the chest wall, the skin and the local complications.