Department of Radiology and Nuclear Medicine, Fukushima Medical University School of Medicine, 1 Hikariga-Oka, Fukushima City, Fukushima, 960-1295, Japan.
Department of Radiology, Fukushima Medical University Hospital, 1 Hikariga-Oka, Fukushima City, Fukushima, 960-1295, Japan.
Acta Neurochir (Wien). 2023 Aug;165(8):2111-2120. doi: 10.1007/s00701-023-05678-4. Epub 2023 Jun 21.
Previous studies have shown that the Valsalva maneuver (VM) causes spinal canal object movements. We hypothesized that this occurs because of cerebrospinal fluid (CSF) flow generated from intradural space reduction. Previous studies using myelograms reported lumbar CSF space changes during inspiration. However, no similar studies have been conducted using modern MRI. Therefore, this study analyzed intradural space reduction during the VM using cine magnetic resonance imaging (MRI).
The participant was a 39-year-old, healthy, male volunteer. Cine MRI involved fast imaging employing steady-state acquisition cine sequence during three resting and VM sets for 60 s each. The axial plane was at the intervertebral disc and vertebral body levels between Th12 and S1 during cine MRI. This examination was performed on 3 separate days; hence, data from nine resting and VM sets were available. Additionally, two-dimensional myelography was performed during rest and the VM.
Intradural space reduction was observed during the VM using cine MRI and myelography. The intradural space cross-sectional area during the VM (mean: 129.3 mm; standard deviation [SD]: 27.4 mm) was significantly lower than that during the resting period (mean: 169.8; SD: 24.8; Wilcoxon signed-rank test, P < 0.001). The reduction rate of the vertebral body level (mean: 26.7%; SD: 9.4%) was larger than that of the disc level (mean: 21.4%; SD: 9.5%; Wilcoxon rank sum test, P = 0.0014). Furthermore, the reduction was mainly observed on the ventral and bilateral intervertebral foramina sides at the vertebral body and intervertebral disc levels, respectively.
The intradural space was reduced during the VM, possibly because of venous dilatation. This phenomenon may be associated with CSF flow, intradural object movement, and nerve compression, potentially leading to back pain.
先前的研究表明，瓦尔萨尔瓦动作（VM）会导致椎管内物体移动。我们假设这是由于硬脊膜内空间减少导致脑脊液（CSF）流动所致。先前使用脊髓造影术的研究报告了吸气时腰椎 CSF 空间的变化。然而，目前还没有类似的使用现代 MRI 进行的研究。因此，本研究使用电影磁共振成像（MRI）分析 VM 期间硬脊膜内空间的减少。
参与者是一名 39 岁的健康男性志愿者。电影 MRI 涉及在三个休息和 VM 组中进行快速成像，每个组持续 60 秒，采用稳态采集电影序列。在电影 MRI 期间，轴向平面位于 T12 和 S1 之间的椎间盘和椎体水平。该检查在 3 天内进行，因此，有 9 个休息和 VM 组的数据可用。此外，在休息和 VM 期间进行二维脊髓造影。
电影 MRI 和脊髓造影均显示 VM 期间硬脊膜内空间减少。VM 时硬脊膜内空间的截面积（均值：129.3mm；标准差 [SD]：27.4mm）明显低于休息时（均值：169.8；SD：24.8；Wilcoxon 符号秩检验，P<0.001）。椎体水平的减少率（均值：26.7%；SD：9.4%）大于椎间盘水平（均值：21.4%；SD：9.5%；Wilcoxon 秩和检验，P=0.0014）。此外，在椎体和椎间盘水平，硬脊膜内空间的减少主要发生在椎骨和椎间孔的腹侧和双侧侧方。
VM 期间硬脊膜内空间减少，可能是由于静脉扩张。这种现象可能与 CSF 流动、硬脊膜内物体移动和神经压迫有关，可能导致背痛。
