Mathematical modeling
  • 2020 № 2 Prediction of time of transurethral holmium lithotripsy in urolitiaz’s treatment

    Introduction. Rational planning of use of the operating room and the high-tech equipment used at treatment of urolithiasis requires knowledge of time spent for ablation of uric concrements which in turn consists of time interval actually of stone breaking and time spent for additional actions: survey of the place of fragmentation, movement of laser fiber to the displaced stone, changes of caliber of an ureteroscop and so forth. Now there are no methods of calculation or prediction of these intervals of time.
    Purpose:   to develop a way of prediction of time of fragmentation of uric stones taking into account additional expenses of
    time when using a contact lithotripsy the holmium laser that on the basis of knowledge of time of operation it is rational to plan loading of the operational room and the high-tech equipment.
    Materials and methods. Own results of measurements of in Vivo of the intervals of time spent for actually destruction of a uric
    stone and for the auxiliary actions necessary at carrying out operation of a lithotripsy and also the general time of final fragmentation of a concrement are given in work. Fragmentation of concrements was carried out by means of rigidny and flexible urethroscop in a ureter and cup pelvis to a system. Additional irrigation of operational area by means of a needle was applied. Methods of statistical data processing and a Statistics and Machine Learning Toolbox package of the Matlab system for prediction of duration of the procedure of fragmentation of concrements a holmium lithotripter of Triple (Medoptotekh) are used.
    Results.  The linear regression model is offered for prediction of the general time on ablation of urinary stone which the general
    time is presented in the form of the sum of time ablation for actually process of breaking, and time of additional costs of performance of auxiliary manipulations. Treat auxiliary actions: washing of field of crushing, a movement of optical fiber because of the shift of its retropulsion of a stone and a respiratory excursion, need of change of caliber of an urethroscop, repeated pass through a urethra and a ureter and so forth. Time of direct breaking of a stone is defined on the basis of the mass of a stone calculated on by the holmium laser measured at KT the volume and density, specific speed of loss of mass of a stone when breaking, energy and frequencies of impulses of a laser lithotripter. Time of additional expenses is presented in the form of the work of time of direct breaking of a stone for coefficient of additional expenses. By measurements in vivo and statistical data processing average and maximum allowed values of coefficients of additional expenses when ablations in various parts of a urinary system are received. Average values of these coefficients are 5.44±2.42 when breaking stones in cup pelvis a system a rigid ureteroscop; 3.86±1.95 when using flexible ureteroscop; 8.92±3.13 when breaking stones in various part of a ureter and 1.36±0.62 when using for additional washing of field of breaking by means of a needle.
    Conclusion. The obtained data of pilot studies of during of crushing of uric concrements and intervals of time of additional costs of carrying out the auxiliary manipulations which are carried out along with the procedure actually of crushing of stones and also the way of additional washing of a cavity of crushing allowing to reduce time of additional expenses when crushing by 4 times is offered. The mathematical model for calculation of duration of the total costs of crushing allowing to predict more precisely duration of operation of a contact lithotripsy the holmium laser in general is developed.

    Authors: Chernega V. S. [3] Eremenko S. N. [2] Eremenko A. N. [3] Tluhovska-Stepanenko N. P. [1]

    Tags: contact  lithotripsy1 holmium  laser1 prediction  of  a  lithotripsy  duration1 uric  stones1 urolithiasis2

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  • 2018 № itm The Network model for Estimation of duration laser contact lithotripsy

    The comparative characteristic of network models with random parameters is executed. It is offered to use as model of the lithotripsy procedure the stochastic network model. In article is examine the assessments questions of laser lithotripsy duration time. The original network alternative stochastic model of the procedure of a laser contact lithotripsy allowing to realize assessment of operation length of a laser lithotripsy in general is developed. It is shown that frequency curve of runtime of stages of operation is described by beta-distribution. Are given the mathematical expressions allowing to calculate optimistic, pessimistic and most probable assessment of duration of separate stages of a lithotripsy and operation in general

    Authors: Chernega V. S. [3] Tluchovskaya-Stepanenko N. P. [1] Eremenko S. N. [2] Eremenko A. N. [3]

    Tags: beta-distribution lithotripsy duration1 laser contact lithotripsy1 network model1

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