守屋 仁彦

Kimihiko MORIYA

北海道大学腎泌尿器外科学分野

Department of Renal and Genitourinary surgery, Hokkaido University

キーワード : acute scrotum, ultrasonography, blood flow signal

急性陰嚢症は陰嚢内容の疼痛・腫脹を呈する様々な疾患の総称であるが，早急な処置を必要とする精索捻転が含まれており，診断が確定できない場合には緊急手術の適応となる．精索捻転の診断・除外にはこれまで核医学検査やMRIなどによる画像診断の有用性も報告されているが，近年では超音波検査が第一選択となっている．精索捻転の診断において，gray-scale modeの超音波検査とともにcolor Dopplerエコーによる精巣内の血流信号の同定はきわめて重要な情報である．当科の経験でも，約1/3は臨床所見と血流信号の存在から緊急手術を回避して保存的に加療を行い精巣の萎縮を認めなかった．しかしながら，精索捻転の2‐3割では血流信号が残存しており，血流信号のある症例でも精索捻転を否定はできない．診察所見の他，渦巻きサイン（whirlpool sign）や精巣周囲の血流増加などの画像にも気を配る必要がある．精巣内に血流信号を認めた症例であっても臨床所見から精索捻転の疑いが強い場合には，緊急手術を躊躇してはならない．たとえ精索捻転であっても術前に血流信号が確認された症例では捻転解除後の精巣の予後は比較的良好であると報告されており，血流信号は予後を反映する指標とも考え得る．しかしながら，超音波検査はoperator-dependentな検査であり，昼夜を問わず発症する急性陰嚢症症例の治療成績の向上のためには，高度なエコー技術を持ったoperatorの育成と救急医療に対応するためのシステム構築が望まれる．

New onset of pain, swelling, and/or tenderness of intrascrotal contents is referred to as acute scrotum. Urgent surgery is indicated unless spermatic torsion is excluded because spermatic torsion is a urological emergency and requires urgent detorsion to salvage the affected testis . While the usefulness of radionuclide imaging or magnetic resonance imaging (MRI) as diagnostic modalities for acute scrotum has been reported in several articles, ultrasound is mostly indicated recently. Evaluation of blood flow in the affected testis by color Doppler ultrasonography as well as gray-scale mode is quite important in the diagnosis of testicular torsion. In our experience, one-third of the patients with acute scrotum were successfully treated with conservative management, avoiding emergent surgery, because of normal blood flow in the affected testis demonstrated by color Doppler ultrasonography. However, it was reported that blood flow in the affected testis was identified in 20-30% of patients with torsion of the spermatic cord. Therefore, detection of blood flow in the affected testis is not always a definitive finding in the diagnosis of torsion of the spermatic cord. Physical examination or the whirl pool sign on color Doppler ultrasound is also important so as not to miss torsion of the spermatic cord. Urgent surgery should not be avoided unless the diagnosis of torsion of the spermatic cord is completely ruled out. Since ultrasound is an operator-dependent modality, a skillful operator in the emergency room would be warranted to make a better management strategy for patients with acute scrotum.