Complications of percutaneous nephrolithotomy in the prone position according with modified Clavien-Dindo grading system.

INTRODUCTION: Clavien-Dindo classification system has been proposed to grade perioperative complications in percutaneous nephrolithotomy. The complications of this technique that have taken place in the last 2 years are reported in this paper according Clavien-Dindo classification. MATERIALS AND METHODS: Between 2011 and 2012 a total of 255 percutaneous nephrolithotomy were performed at our center for stones more than 2 cm in size. In order to determine the incidence of complications classified in the modified Clavien-Dindo system, statistical analysis of the data obtained was carried out. RESULTS: During the period analyzed, 255 percutaneous nephrolithotomy were performed in 249 patients, 41% of the right side, 57% of the left side and 2% bilateral and simultaneous. 137 and 112 patients were males and females, respectively. The most prevalent comorbidities were: hypertension (AHT) in 101 patients (40.6%), BMI>30 in 81 patients (32%), diabetes mellitus in 46 patients (18.5%) and coagulation abnormalities in 24 patients (9.6%). A total of 70 cases (27.4%) were distributed according to Clavien-Dindo classification: grade i, 8.4%, grade ii 8.4%, grade iiia 4.4%, grade iiib 6% grade iva .8%, grade ivb: 0% and grade v 0%. CONCLUSIONS: A graded classification scheme for reporting the complications of percutaneous nephrolithotomy is useful for monitoring and reporting outcomes. We propose a standardized use of this classification in order to make the results comparable among different centers performing the technique.

An empirical Bayes approach to the estimation of the incidence curve of HIV infection.

A new approach is proposed for estimating the incidence curve of HIV infection and obtaining short term prediction of AIDS incidence. It is based on the method of back calculation which utilizes the fact that AIDS incidence is generated from HIV infection incidence by convolution with the incubation period distribution, but avoids the difficulties associated with approximating the infection incidence curve by a class of step functions. Instead, the infection incidence is modelled as a simple stochastic epidemic process which ensures smoothness of the estimate. We first derive the distribution of AIDS incidence knowing infection incidence. The best linear estimators of infection incidence as well as future AIDS incidence are given; a smoothed past AIDS incidence is also obtained. The parameters of the stochastic infection process can be estimated by maximum likelihood using a normal approximation to the marginal distribution of the AIDS incidence. This approach is applied to AIDS incidence data in the United States up to mid 1987. We find that the epidemic started in mid 1976, peaked at the end of 1983 and dropped afterwards.

Homenaje al profesor Doctor Hernán Alessandri Rodríguez / Tribute to professor Hernán Alessandri Rodríguez, M. D

This is the Laudatory speech given at the Academy of Medicine by Dr. Raúl Etcheverry in memory of the late Professor Hernán Alessandri (1900-1981). The lecture, a hematologist and one of Dr. Alessandri's disciples gave touching notes on his outstanding personality, memories of this scholarly by career at the Department of Medicine of the Salvador Hospital in Santiago, and on his contributions to Chilean Medicine.