Treatment Of Scoliosis Associated With Syringomyelia By 3-Dimensional Correction

Syringomyelia is a cystic, fluid-filled cavitation within the spinal cord. Hydromyelia is the expansion in the central canal of spinal cord. These are different procedure and difficult to distinguish, so often substituted by each other. Syringomyelia are usually diagnosed by MRI before any clinical signs since the invention of MRI. We could often encounter the scoliosis accompanied by syringomyelia by the procedure of regular preoperative MRI examination. The scoliosis accompanied with syringomyelia often associates with abnormality of the central neural system ,such as Arnold Chiari malformation (ACM type Ⅰ,ACM type Ⅱ), tethered cord, myelomingocele (neural tube defects)and congenital scoliosis. Many patients with small syringomeylia are often with no obvious clinical findings. The main clinical finding of syringomyelia is scoliosis, according to the report there are 85% syringomyelia patients accompanied with scoliosis; the others include spinal function deficit and pain associated with scoliosis(low back pain, headache, neck pain, the incidence are 47.1%, 32.9%, 28.6%, respectively), intrinsic adductor muscle atrophy of hands, superficial abdominal reflex loss(95 % ). The spinal sensory function deficits include: segmental sensory disturbance. All sensory will loss at the affected level, if the syrinx is located at the entrance of posterior root, where the long tract enters the correspond spinal roots. When the syrinx affects unilateral or bilateral long tracts, the sensory deficits will be contralateral or bilateral below the affected level. When the syrinx affect the lateral gray horn, there will be obvious sympathetic function deficits, such as upper extremity atrophy, skin sclerosis, recurrent ulcer, cyanosis, perspiration abnormity. The indication of syringomyelia surgery is to stable the clinical manifestation. When there is no obvious clinical signs, most doctors don't agree to operatively treat the ACM and syringomyelia in advance, but with cautious follow-up instead. Non-operative method could not prevent scoliosis progression, but it's necessary to correct the scoliosis. Qiuyong et al. provided to correct scoliosis after gradually Halo traction with no obvious neurological deficits and along with close follow-up for two weeks. If there is no syringomyelia treatment before correction, we should prevent cord tract, and use spinal inspection. The mechanism by which scoliosis develops secondary to syringomyelia is not yet to be determined, although several theories have been proposed. Some authors have suggested the idea of an asymmetrically enlarging cyst that injures either the lower motor neurons or the dorso-medial and ventromedial nuclei of the gray matter of the anterior horn of the spinal cord, thereby creating imbalance of trunk musculature and predisposing to scoliosis. Gardnerand Collis suggested that during fetal development, the mass effect of the syrinx caused vertebral deformity, resulting in scoliosis. This lack of understanding of the pathophysiology of scoliosis in syringomyelia makes it difficult to determine the effect of syrinx size and course on the curve. But several studies have reported some relationship between the location and size of the syrinx and the location and type of scoliosis. Many authors agree on the surgical treatment of syrinx before scoliosis correction for all patients, but this additional surgery will increase the complications and against the primary willing. So we wonder whether it is necessary for all the patients to deal with the syrinx before scoliosis correction? We reviewed all the related articles and case reports, and discovered that those patient with dangerous complications were usually with significant clinical findings preoperatively, and the internal instru-mentations are Harrington, TSRHTM and Cotrel-DuboussetTM. According to the surgery principles, the cord can be easily hurt by longitudinal traction, over-correction, intraspinal canal hooks and sublaminar wires during surgery procedure. We have been using the direct derotation method to correct scoliosis with segmental pedicle screw-rod system and posterior instrumentation instead of various hooks and sublaminar wires since 1999, which could invade intraspinal canal, and could avoid damageto cord. The principle of this method is to correct scoliosis by direct rod derotation instead of longitudinal traction, and mostly prevent the cord damage, and additional to which we regular use SEP that is also an effective method to prevent cord damage during operation. We evaluated the curative effect of scoliosis with syringomyelia treated by the segmental pedicle screw system through the clinical data and follow-up results of 21 scoliosis patients with syringomyelia treated by segmental pedicle screw system and posterior instrumentation from 1999 to 2005. 21 patients of scoliosis with syringomyelia, the mean preoperative Cobb's angel in the coronal plane is 64.9°(38°-121°); the postoperative Cobb's angel is 21.2°(1°-78°), mean correct rate is 69.5% (31.0%-97.9%). the mean follow-up is 27 months (1-72). There is a mean loss of 4.4°in coronal plane with 12 cases. The mean preoperative Cobb's angel in the sagital plane is 35.6°(3°-83°); the mean postoperative Cobb's angel is 26.6°(17°-55°). There is a mean loss of 6.3°in sagital plane with 12 cases during the follow-up. There is no complications of infection, junctional kyphosis, trunk imbalance and irreversible neural deficits. Among the 21 patients , 2 cases with no preoperative neurological signs, 19 cases with slight neural deficits signs. And there are 19 cases (90.5%)with no or better changes, the other two with abdominal reflex loss. Conclusion: it is safe to correct the scoliosis patients with...