Watanabe Kei, Hasegawa Kazuhiro, Hirano Toru, Endo Naoto, Yamazaki Akiyoshi, Homma Takao
Department of Orthopaedic Surgery, Niigata University Graduate School of Medical and Dental Sciences; Niigata Central Hospital and Niigata Spine Center, Niigata, Japan.
J Neurosurg Spine. 2005 Aug;3(2):86-91. doi: 10.3171/spi.2005.3.2.0086.
The mechanism underlying cervical flexion myelopathy (CFM) is unclear. The authors report the results of anterior decompression and fusion (ADF) in terms of neurological status and radiographically documented status in young patients and discuss the pathophysiological mechanism of the entity.
Twelve patients underwent ADF in which autogenous iliac bone graft was placed. The fusion area was one segment in four cases, two segments in seven, and three segments in one. Neurological status, as determined by the Japanese Orthopaedic Association (JOA) score, radiographic findings, and intraoperative findings were evaluated. The mean follow-up period was 63.3 months (range 20-180 months). Grip strength was significantly improved and sensory disturbances resolved completely. Intrinsic muscle atrophy, however, persisted in all patients at the final follow-up examination. Local kyphosis in the flexed-neck position at the fusion levels was corrected by surgery. Preoperative computerized tomography myelography revealed that the cord compression index, which was calculated by anteroposterior and transverse diameters of the spinal cord, decreased to 33 +/- 6.2% in the flexed-neck position from 39.7 +/- 9.9% in the extended-neck position. The anterior dura mater-spinal cord distance decreased to 1.9 +/- 0.7 mm in the flexed-neck position from 4 +/- 1.2 mm in extended-neck position. The posterior dura mater-spinal cord distance increased to 2.5 +/- 1.1 mm in the flexed-neck position from 1.3 +/- 0.5 mm in the extended-neck position.
Postoperative neurological status was improved in terms of grip strength, sensory disturbance, and JOA score, and local kyphosis in the flexed-neck position at the fusion levels was reduced and stabilized by ADF. In most cases local kyphosis in the flexed-neck position was demonstrated at the corresponding disc level, as were cervical cord compression and decrease of the anterior wall of the dura mater-spinal cord distance in the flexed-neck position. Therefore, the contact pressure between the spinal cord and anterior structures (intact vertebral bodies and intervertebral discs) in the mobile and kyphotic segments was considered to contribute to the onset of CFM. The ADF-related improvement of the clinical symptoms, preventing kyphotic alignment in flexion and decreasing movement of the cervical spine, supports the idea of a contact pressure mechanism. Furthermore, short ADF performed only at the corresponding segments can preserve more mobile segments compared with posterior fusion. Thus, ADF should be the first choice in the treatment of CFM.
颈椎屈曲型脊髓病（CFM）的潜在机制尚不清楚。作者报告了年轻患者前路减压融合术（ADF）在神经功能状态和影像学记录方面的结果，并讨论了该疾病的病理生理机制。
12例患者接受了ADF手术，并植入自体髂骨。融合节段为1个节段的有4例，2个节段的有7例，3个节段的有1例。对日本骨科协会（JOA）评分、影像学表现和术中所见所确定的神经功能状态进行了评估。平均随访期为63.3个月（范围20 - 180个月）。握力显著改善，感觉障碍完全消失。然而，在最后一次随访检查时，所有患者的固有肌萎缩仍然存在。融合节段在颈部屈曲位的局部后凸通过手术得到矫正。术前计算机断层扫描脊髓造影显示，通过脊髓前后径和横径计算的脊髓压迫指数，在颈部伸展位时为39.7±9.9%，在颈部屈曲位时降至33±6.2%。硬脊膜前间隙脊髓距离在颈部伸展位时为4±1.2mm，在颈部屈曲位时降至1.9±0.7mm。硬脊膜后间隙脊髓距离在颈部伸展位时为1.3±0.5mm，在颈部屈曲位时增至2.5±1.1mm。
ADF术后在握力、感觉障碍和JOA评分方面神经功能状态得到改善，融合节段在颈部屈曲位的局部后凸得到减轻并稳定。在大多数情况下，颈部屈曲位的局部后凸在相应椎间盘水平出现，颈部脊髓压迫以及颈部屈曲位硬脊膜前间隙脊髓距离减小也在相应水平出现。因此，活动和后凸节段脊髓与前方结构（完整椎体和椎间盘）之间的接触压力被认为是CFM发病的原因。ADF相关的临床症状改善、防止屈曲时后凸排列以及减少颈椎活动，支持了接触压力机制的观点。此外，与后路融合相比，仅在相应节段进行的短节段ADF可以保留更多的活动节段。因此，ADF应是CFM治疗的首选方法。
