妊婦の側臥位におけるヤコビ線の位置に関する後ろ向き検討

The Vertebral Level of the Jacobi Line in Pregnant Women Examined in Lateral Position：A Retrospective Analysis

要旨

　妊婦における側臥位でのヤコビ線が脊椎と交わる位置を後ろ向きに検討した。

　帝王切開もしくは無痛分娩を施行される妊婦を対象とした。側臥位で触診によるヤコビ線の位置を超音波で同定した。帝王切開では術後のX線における両側上腸骨稜間線の位置も同定した。

　帝王切開33名，無痛分娩27名からデータを得た。側臥位でのヤコビ線の位置はL2-3が2名，L3棘突起が2名，L3-4が34名，L4棘突起が10名，L4-5が11名，L5棘突起が1名であった。術後の仰臥位でのX線では全員がL4棘突起より尾側であった。

　側臥位の妊婦でヤコビ線はL4棘突起より頭側へ変位している場合があった。

　Background：It has been reported that in pregnant women, the position of the Jacobi line is more cephalad compared to other patients. Such a shift of the Jacobi line in pregnant women when they are examined in the lateral position has rarely been studied.

　Methods：We retrospectively analyzed the vertebral levels of the Jacobi line in consecutive cases of pregnant women examined in the lateral position at our institution. The Jacobi line was identified by palpation of the iliac crests. The vertebral level of the Jacobi line was determined in each case with the use of ultrasound. Data were obtained from 33 cesarean section patients and 27 painless delivery patients. In the cesarean section group, the locations of the intercrestal lines were also identified on postoperative X-rays.

　Results：The location of the Jacobi line was L2/3 in two patients, L3 in two, L3/4 in 34, L4 in 10, L4/5 in 11, and L5 in one patient. In all of the patients, supine-position postoperative X-rays revealed that the Jacobi lines were at the L4 spinous process or a more caudal level.

　Conclusions：In some pregnant women examined in the lateral position, the Jacobi line was displaced to a more cephalad level than the L4 spinous process, which may contribute to a spinal cord injury.