Destruction of renal parenchyma at percutaneous nephrolithotripsy; experimental study

Abstract

PNLに際して, 外筒を皮膚の刺入点を支点として様々な角度に回転させるとき, どの程度の角度で実質が破壊されるかを知るために, 実験的検討を行った.右腎盂腫瘍(T2N0M0)のため摘出された54歳女の腎臓を用い, その外縁より腎盂に向かって穿刺した.次いでAmplatz拡張器にてその経路を26 Fまで拡張した.そのまま26 Fの拡張器を留置し, それを治具中グリ盤(Hydroptic-6)の金属棒に固定した.この金属棒を腎下極に向かって平行移動させるとき, 腎実質にかかる外力を測定し, その接線方向, 法線方向それぞれの成分より腎実質が破壊された時の回転角を18度と推定した.また別に腎実質の破壊断面の形状より推定された角度は37度であった.従って今回の実験からは, PNLにおける外筒の法線方向に対する安全な回転角の上限は18度から37度の範囲と考えられた

The destruction of renal parenchyma caused by excess deflection of the sheath was examined to determine at what level of force the renal parenchyma was ruptured during PNL. The kidney obtained from right nephroureterectomy due to renal pelvic cancer (stage T2N0M0) of a 54-year-old female patient was punctured at the posterolateral portion with a puncture needle. The tract was dilated up to 26 Fr. in size with an Amplatz renal dilation set. The 26 Fr. sheath was left in the tract and fixed to the metal bar attached to Gig Boring Machine (Hydroptic-6) which could sense the change of pressure added to the renal parenchyma in the parallel movement of the metal bar. The critical angle in regard to the deflection of the renal parenchyma in order not to cause the rupture of renal parenchyma on PNL was calculated from both the resultant force and the shape of the wound of renal parenchyma at rupture. The safety angle against horizontal plane of the tract ranged from 18 to 37 degree.