Kamo Masatsugu, Kajimoto Yoshinaga, Ohmura Tomohisa, Kameda Masahiro, Tucker Adam, Miyake Hiroji, Wanibuchi Masahiko
Department Neurosurgery, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.
Department Neurosurgery, Nishinomiya Kyoritsu Neurosurgical Hospital, Nishinomiya, Japan.
Front Neurol. 2022 May 23;13:882757. doi: 10.3389/fneur.2022.882757. eCollection 2022.
We identified a new type of shunt malfunction (SM) in patients with normal pressure hydrocephalus (NPH). It is induced by weight change and can be treated with valve readjustment. There were two types of SM as follows: Underdrainage induced by the weight gain and overdrainage induced by the weight loss. This study aims to elucidate this mechanism by assessing the shunt pressure environment.
The total pressure environment of the shunt system was prospectively studied in patients with shunted NPH at Osaka Medical College Hospital from 1999 to 2005. We measured the pressure environment during the initial pressure setting of the valve by the intracranial pressure (ICP) guide, after setting the valve, and when SM was suspected. We evaluated ICP, intra-abdominal pressure (IAP), and hydrostatic and perfusion pressures of the shunt system in the sitting and supine positions. The target ICP for valve setting was empirically set at the range from -8 to -13 mm Hg in the sitting position, referring to the external auditory meatus. During the study period, we identified five cases of SM induced by weight change and assessed the changes in the pressure environment across pre-SM, SM, and post-SM.
In four cases of underdrainage, gait disturbance worsened with an average weight gain of 6.8 ± 1.2 kg. With weight gain, IAP and ICP increased by 8.8 ± 1.6 and 4.8 ± 1.0 mm Hg, respectively. Consequently, ICP increased to -6.5 ± 1.9 mm Hg. One overdrainage patient developed an asymptomatic chronic subdural hematoma (CSDH) with a weight loss of 10 kg. With the weight loss, both IAP and ICP decreased by 5 mm Hg, and concomitantly, ICP decreased to -18 mm Hg. In all patients, the valve readjustment restored their ICP to the target pressure. After the valve readjustment, the gait disturbance improved immediately, and the CSDH disappeared after 1 month.
In patients with shunts, the weight change was linked to ICP IAP. Due to the weight change, the underdrainage occurred when ICP was above the target pressure, and the overdrainage occurred when ICP was below it. We named this SM as the weight and abdominal pressure-induced shunt trouble. The patients with SM along with weight changes should be the first to be tried for the valve readjustment.
我们在正常压力脑积水（NPH）患者中发现了一种新型的分流器故障（SM）。它由体重变化引起，可通过调整阀门进行治疗。SM有以下两种类型：体重增加引起的引流不足和体重减轻引起的引流过度。本研究旨在通过评估分流器压力环境来阐明这一机制。
1999年至2005年，在大阪医科大学医院对接受分流术的NPH患者的分流系统总压力环境进行了前瞻性研究。我们在通过颅内压（ICP）引导进行阀门初始压力设置时、设置阀门后以及怀疑出现SM时测量压力环境。我们评估了坐位和仰卧位时的ICP、腹腔内压力（IAP）以及分流系统的静水压和灌注压。阀门设置的目标ICP根据外耳道经验性设定为坐位时-8至-13 mmHg。在研究期间，我们确定了5例由体重变化引起的SM病例，并评估了SM前、SM期间和SM后压力环境的变化。
在4例引流不足的病例中，步态障碍随着平均体重增加6.8±1.2 kg而恶化。随着体重增加，IAP和ICP分别增加8.8±1.6和4.8±1.0 mmHg。结果，ICP增加到-6.5±1.9 mmHg。1例引流过度的患者体重减轻10 kg后出现无症状慢性硬膜下血肿（CSDH）。随着体重减轻，IAP和ICP均下降5 mmHg，同时，ICP降至-18 mmHg。在所有患者中，阀门调整使他们的ICP恢复到目标压力。阀门调整后，步态障碍立即改善，CSDH在1个月后消失。
在分流患者中，体重变化与ICP和IAP相关。由于体重变化，当ICP高于目标压力时发生引流不足，当ICP低于目标压力时发生引流过度。我们将这种SM命名为体重和腹腔压力引起的分流问题。伴有体重变化的SM患者应首先尝试进行阀门调整。
