Puncture Path Variation Between The Prone,Lateral,and Supine Oblique Positions For Percutaneous Nephrolithotomy On Computed Tomography

Objective: To evaluate the puncture path and anatomical variations between the prone,lateral,and supine oblique positions which were used in PCNL.Methods: A total of 40 patients with renal stones prepared for PCNL were included.Patients were divided into group A and group B by affected side,20 patients per group.A dose computed tomography urography in a prone,lateral and supine oblique position was performed.The access tract length,subcutaneous tissue length,maximum access angle,and the no coverage ratio were measured in axial and coronal images.The parameters were analyzed by the paired rank-sum test.Results:The access tract length: The mean tract lengths in all groups were shortest in the prone position,and the supine oblique position were second.The difference between these groups(the left and right upper,middle poles groups of lateral vs prone,the right upper poles groups of supine oblique vs prone)has statistical significance(P<0.05);Subcutaneous tissue length: The mean tractlengths in all groups were longest in the supine oblique.The difference between these groups(the left middle and right upper,middle poles groups of supine oblique vs prone,the left lower and righter all groups of supine oblique vs lateral)has statistical significance(P<0.05);Maximum access angle: The mean maximum access angle in the middle and lower poles of kidney group in prone position were minimum,and the supine oblique position were second.The difference between these group(left middle and right lower poles groups of supine oblique vs prone,left and right middle,lower poles groups of lateral vs prone)has statistical significance(P<0.05);No coverage ratio: The mean no coverage ratio in all groups were maximum in the supine oblique position,and the prone position were second.No significant difference in all groups(P>0.05).Conclusion: In PCNL,the puncture path was shorter in the prone position when compared with lateral and supine oblique position;obese patients’ surgical site subcutaneous fat tissue were more thickness;the maximum access angle in middle and lower puncture path were larger in lateral and supine oblique position.