Kakizawa Yukinari, Seguchi Tatsuya, Kodama Kunihiko, Ogiwara Toshihiro, Sasaki Tetsuo, Goto Tetsuya, Hongo Kazuhiro
Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
J Neurosurg. 2008 Mar;108(3):483-90. doi: 10.3171/JNS/2008/108/3/0483.
Neuroimages often reveal that the trigeminal or facial nerve comes in contact with vessels but does not produce symptoms of trigeminal neuralgia (TN) or hemifacial spasm (HFS). The authors conducted this study to determine how often the trigeminal and facial nerves came in contact with vessels in individuals not suffering from TN or HFS. They also investigated the correlation between aging and the anatomical measurements of the trigeminal and facial nerves.
Between November 2005 and August 2006, 220 nerves in 110 individuals (60 women and 50 men; mean age 55.1 years, range 19-85 years) who had undergone brain magnetic resonance (MR) imaging for other reasons were studied. The lengths, angles, ratio, and contact points were measured in each individual. A correlation between each parameter and age was statistically analyzed.
The mean (+/- standard deviation) length of the trigeminal nerve was 9.66 +/- 1.71 mm, the mean distance between the bilateral trigeminal nerves was 31.97 +/- 1.82 mm, and the mean angle between the trigeminal nerve and the midline was 9.71 +/- 5.83 degrees . The trigeminal nerve was significantly longer in older patients. Of 220 trigeminal nerves, 108 (49.0%; 51 women and 57 men) came in contact with vasculature. There was 1 contact point in 99 nerves (45%) and 2 contact points in 9 nerves (4.1%). Contact without deviation of the nerve was seen in 91 individuals (43 women and 48 men), and mild deviation was noted in 17 individuals (8 women and 9 men). There was no moderate or severe deviation in any individual in this series. The mean length of the facial nerve was 29.78 +/- 2.31 mm, the mean distance between the bilateral facial nerves was 28.65 +/- 2.22 mm, the angle between the nerve and midline was 69.68 +/- 5.84 degrees , and the vertical ratio at the porus acusticus was 0.467 +/- 0.169. Of all facial nerves, 173 (78.6%; 101 in women and 72 in men) came in contact with some vasculature. Contact without deviation was seen on 64 sides (in 37 women and 27 men), mild deviation on 98 sides (in 57 women and 41 men), and moderate deviation on 11 sides (in 7 women and 4 men). There was no severe deviation of the facial nerve in this series. The proximal length of the facial nerve, interval, angle, and ratio against the age were significantly shorter or smaller in the older individuals.
The findings in asymptomatic individuals in this study will help in deciding which findings observed on MR images may cause symptoms. In addition, the authors describe the variations of normal anatomy in older individuals. Knowledge of the normal anatomy helps to hone the diagnostic practices for microvascular decompression, which may increase the feasible results on such surgery.
神经影像检查常常显示三叉神经或面神经与血管相接触，但并未产生三叉神经痛（TN）或面肌痉挛（HFS）的症状。作者开展此项研究以确定在未患TN或HFS的个体中，三叉神经和面神经与血管接触的频率。他们还研究了衰老与三叉神经和面神经解剖学测量值之间的相关性。
在2005年11月至2006年8月期间，对110例（60例女性和50例男性；平均年龄55.1岁，范围19 - 85岁）因其他原因接受脑部磁共振（MR）成像检查的个体中的220条神经进行了研究。测量了每个个体中神经的长度、角度、比例及接触点。对每个参数与年龄之间的相关性进行了统计学分析。
三叉神经的平均（±标准差）长度为9.66±1.71mm，双侧三叉神经之间的平均距离为31.97±1.82mm，三叉神经与中线之间的平均角度为9.71±5.83度。老年患者的三叉神经明显更长。在220条三叉神经中，108条（49.0%；女性占51条，男性占57条）与血管系统相接触。99条神经（45%）有1个接触点，9条神经（4.1%）有2个接触点。91例个体（女性43例，男性48例）可见神经无偏移的接触，17例个体（女性8例，男性9例）有轻度偏移。本系列中无任何个体出现中度或重度偏移。面神经的平均长度为29.78±2.31mm；双侧面神经之间的平均距离为28.65±2.22mm；神经与中线之间的角度为69.68±5.84度；在听门处的垂直比例为0.467±0.169。在所有面神经中，173条（78.6%；女性101条，男性72条）与某些血管系统相接触。64侧（女性37例，男性27例）可见无偏移的接触，98侧（女性57例，男性41例）有轻度偏移，11侧（女性7例，男性4例）有中度偏移。本系列中面神经无重度偏移。老年个体面神经的近端长度、间距、角度及与年龄相关的比例明显更短或更小。
本研究中无症状个体的研究结果将有助于确定在MR图像上观察到的哪些结果可能导致症状。此外，作者描述了老年个体正常解剖结构的变异情况。了解正常解剖结构有助于优化微血管减压的诊断方法，这可能会提高此类手术的成功率。
