Kyoshima Kazuhiko, Kuroyanagi Takayuki, Oya Fusakazu, Kamijo Yukihiro, El-Noamany Hossam, Kobayashi Shigeaki
Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
J Neurosurg. 2002 Mar;96(2 Suppl):239-49. doi: 10.3171/spi.2002.96.2.0239.
Idiopathic syringomyelia, which is not associated with any definite pathogenic lesions, has been treated mainly by shunting of the syrinx and rarely by craniocervical decompression. The authors report four cases of syringomyelia thought to be idiopathic syringomyelia but treated by craniocervical decompression with favorable results. Syringomyelia was present without hindbrain herniation. In such cases, the subarachnoid space anterior to the brainstem at the level of the foramen magnum is usually open but the cisterna magna is impacted by the tonsils, a condition the authors term "tight cisterna magna." All patients underwent foramen magnum decompression and C-1 laminectomy, and the outer layer of the dura was peeled off. Further intradural exploration was performed when outflow of cerebrospinal fluid (CSF) from the fourth ventricle was deemed to be insufficient. Postoperatively, improvement in symptoms and a reduction in syrinx size were demonstrated in three patients, and a reduction in ventricle size was shown in two. Syringomyelia associated with tight cisterna magna should not be classified as idiopathic syringomyelia; rather, it belongs to the category of organic syringomyelia such as Chiari malformation. A possible pathogenesis of cavitation is obstruction of the CSF outflow from the foramen of Magendie, and the cavity may be a communicating dilation of the central canal. Ventricular dilation may depend on the extent to which CSF drainage is impaired from the foramina of Luschka. These cavities may respond to craniocervical decompression if it results in sufficient CSF outflow from the foramen of Magendie, even in cases with concomitant hydrocephalus.
特发性脊髓空洞症与任何明确的致病病变无关，主要通过脊髓空洞分流术治疗，很少采用颅颈减压术。作者报告了4例被认为是特发性脊髓空洞症但采用颅颈减压术治疗且效果良好的病例。这些病例存在脊髓空洞症但无后脑疝。在这类病例中，枕骨大孔水平脑干前方的蛛网膜下腔通常是开放的，但枕大池受扁桃体压迫，作者将这种情况称为“狭窄枕大池”。所有患者均接受了枕骨大孔减压术和C-1椎板切除术，并剥离了硬脑膜外层。当认为第四脑室脑脊液（CSF）流出不足时，进一步进行硬脊膜内探查。术后，3例患者症状改善且脊髓空洞大小减小，2例患者脑室大小减小。与狭窄枕大池相关的脊髓空洞症不应归类为特发性脊髓空洞症；相反，它属于诸如Chiari畸形等器质性脊髓空洞症范畴。空洞形成的一种可能发病机制是马根迪孔脑脊液流出受阻，且空洞可能是中央管的交通性扩张。脑室扩张可能取决于卢施卡孔脑脊液引流受损的程度。即使在伴有脑积水的病例中，如果颅颈减压术能使马根迪孔有足够的脑脊液流出，这些空洞也可能对其产生反应。
