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.
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.