Can renal stone size and the use of the nephrolithometric system increase the efficacy of predicting the risk of failure of percutaneous nephrolithotripsy? / O tamanho do cálculo renal e o uso do sistema nefrolitométrico podem aumentar a eficácia de predizer o risco de falha de nefrolitotripsia percutânea?

ABSTRACT

ABSTRACT Objective: to verify the association of success rate of percutaneous lithotripsy, Guy score and size of the stone. Methods: one hundred patients submitted to percutaneous nephrolithotripsy were evaluated. All stones were classified according to Guy Score. Patient free of stone was considered when residual fragments were ≤2mm. Results: according to guy Score, 54% were score 1 (Group 1), 18% score 2 (Group 2), 15% score 3 (Group 3), and 13% score 4 (Group 4). Success was observed in 77.77% in Group 1, 27.77% in group 2, 26.6% in Group 3, and 7.69% in Group 4. In patients with Guy score 1, there was statistical significance of prediction of free stone rate when evaluated according to the size of the stone. Among groups 2, 3 and 4 there was no statistical significance, but it was observed a trend in relation to stone size, the bigger the higher the chance of residual fragments. Conclusion: nephrolithometry by Guy Score and size of the stone are single predictors of success of percutaneous nephrolithotripsy. Stone size may influence success rate of patients with Guy Score 1.

RESUMO

RESUMO Objetivo: verificar a associação entre taxa de sucesso de nefrolitotripsia percutânea, escore de Guy e tamanho do cálculo. Métodos: foram avaliados 100 pacientes submetidos à nefrolitotripsia percutânea. Todos os cálculos foram classificados de acordo com o escore de Guy. Consideramos o paciente livre de cálculos quando os fragmentos residuais fossem menores ou iguais a 2mm. Resultados: de acordo com o escore de Guy, 54% tinham escore 1 (Grupo 1), 18% escore 2 (Grupo 2), 15% escore 3 (Grupo 3) e 13% escore 4 (Grupo 4) . Houve resolução de 77,77% no grupo 1, de 27,77% no grupo 2, de 26,6% no grupo 3 e de 7,69% no grupo 4. Houve significância estatística para predição de taxa livre de cálculos entre os pacientes com escore de Guy 1 quando avaliados de acordo com o tamanho do cálculo. Entre os grupos 2, 3 e 4 não houve significância estatística, porém observamos tendência de que quanto maior o tamanho do cálculo, maior a chance de cálculo residual. Conclusão: a nefrolitometria pelo Escore de Guy e o tamanho do cálculo são preditores isolados para avaliação de sucesso da nefrolitotripsia percutânea. O tamanho do cálculo pode influenciar a taxa de sucesso de pacientes com Escore de Guy 1.