木戸 浩一郎¹, Barbera Antonio², 梁 栄治¹, 綾部 琢哉¹

Kouichiro KIDO¹, Antonino BARBERA², Eiji RYO¹, Takuya AYABE¹

¹帝京大学産婦人科, ²Banner Health Center Department of Obstetrics and Gynecology, Banner Fort Collins Medical Center, Medical Director, Women and Infant Services

¹Teikyo University School of Medicine, Department of Obstetrics and Gynecology, ²Banner Health Center Department of Obstetrics and Gynecology, Banner Fort Collins Medical Center, Medical Director, Women and Infant Services

キーワード : transperineal ultrasound, sono-urodynamics, labor progress, sonopartogram, anal sphincter injury

経会陰超音波は，会陰部に超音波の探触子（プローブ）をあてて，体腔内を観察する超音波検査手法である．1970‐80年代から泌尿器科領域で利用されていた手法であるが，近年，産婦人科領域でも活用されつつある．本法は肛門括約筋を含む骨盤底や，経腟分娩時に産道を下降する胎児の児頭，の描出に優れており尿失禁，分娩進行，産褥の肛門括約筋の損傷，などの評価に利用されつつある．超音波検査という特性上，診察室，陣痛室，分娩室で非侵襲的に簡便に施行可能で，動画を含めて画像という形で保存可能なため，単に静的・形態的面だけではなく動的・機能的の評価を客観に行える．骨盤底を明瞭に描出することで，尿道過運動・内因性括約筋不全を評価することが可能で，女性に多い腹圧性尿失禁・切迫性尿失禁の診断に有用で，治療の経過観察にも利用される．また，分娩時には恥骨と児頭との位置関係を描出することにより，児頭下降を経時的に客観的に評価し分娩進行の評価に利用される．3D超音波では児頭の回旋も描出することが可能であり，回旋異常の診断も可能とする報告もある．従来の内診と同等に有用とする報告もある．また産褥の肛門括約筋を描出する研究では，従来考えられていたよりも，肛門括約筋の損傷が高頻度に発生する可能性が指摘されている．経腹・経腟超音波検査の基本的な経験と骨盤底の解剖学的知識があれば，本法の実施と解釈は比較的容易であるため，今後，産婦人科領域で広く普及することが期待される．

Transperineal ultrasound (TPU) started to be used in the 1970-80s for assisting biopsies of the prostate. Only in the mid to late 1990s did it become a tool used by both urogynecologists and obstetricians. Different from invasive urodynamic tests, and digital vaginal or digital rectal examination, this approach is noninvasive and well tolerated by patients. While MRI or CT examination requires expensive equipment and highly trained personnel, TPU is easy to perform and can be done in real time to answer the clinical question being investigated. Furthermore, cine loop clips are easily acquired and stored for later evaluation and for educational purposes. In urogynecology, TPU can be used to visualize the urethra and its hypermobility, being useful for diagnosis of stress urinary incontinence. During labor, TPU allows an objective assessment of fetal head descent in the birth canal. Many other measurements have been proposed by different scientists: the angle of progression, the head direction, the progression distance, and the head-perineum distance. The angle of progression is the most widely used parameter. TPU is also used to assess fetal head rotation, with both 2D and 3D images. The latter helps with the visualization of fetal sagittal suture in real time. It is clear that with all these potentialities, TPU can become the most objective way to help in making a key decision at time of delivery: perform an operative vaginal or potentially difficult cesarean delivery. In postpartum, TPU can be used to visualize the rectal sphincter, and it is being used to identify patients at high risk for fecal incontinence. Nowadays, TPU is becoming the most advanced and objective tool used in many labor and delivery units around the world during the first and second stage of labor to assess fetal position and fetal station, and in puerperium to visualize the rectal sphincter.