Clinical Features And Treatment Of Tethered Cord Syndrome With Syringomyelia

Objective With the increasing use of magnetic resonance imaging, terminal syringomyelia (segmental cystic dilation of the caudal one-third of the spinal cord) in association with the tethered cord syndrome has become an appreciable finding. This study attempted to define the clinical significance of this associated pathological condition by describing its clinical and radiological characteristics and its contribution to the clinical status of patients with tethered spinal cords, if any, brought after syrinx decompression on theclinical outcome of tethered cord syndrome.Materials and Methods Of 209 consecutive patients with tethered cord syndrome who presented to First Hospital of Shanxi Medical University and S hanxi Maternal and Child Health Hospital between 2000 and 2007, 32 patients with terminal syringomyelia were enrolled in this study. To 32 cases of pediatric tethered cord was randomly assigned into two treatment groups: those in whom an untethering procedure was performed (Group I) and those in whom this procedure was combined with syrinx decompression (Group II). The 1-year follow-up clinical results obtained in the two groups, in correlation with MR imaging findings, were compared to evaluate the benefit of added syrinx drainage. Surgical treatment used two basic approaches, i.e., simple untethering or untethering with concurrent syrinx drainage.Results Comparison of the average ages, tethering causes, for the two groups showed no statistical significance. However, the frequency of sacral conus involvement in the syrinx group (40%), compared with the nonsyrinx group (12%), was highly statistically significant (P< 0.01). In general, the neurological manifestations for the syrinx group were similar to those for the nonsyrinx group. However, higher incidences of monoparesis, sensory loss, long tract signs, encopresis, and progressive scoliosis were noted for the syrinx group. Clinical follow-up evaluation revealed that surgical drainage of the syrinx, when combined with spinal cord untethering, resulted in better outcomes in terms of resolution of sensory deficits (p = 0.036) and bladder dysfunction (p =0.05). The improvement in clinical outcome correlated with the radiologically documented resolution of the syrinx cavity;The clinical outcome between simple untethering and untethering with concurrent syrinx drainage syrinx drainage showed no statistical significance in petients of small cysts (syrinx index <40%),but showed statistical significance in petients of large cavitations (syrinx index≥40). however, response rates of symptoms differed for each tethering subgroup.Conclusion 1)Although the persistenceof a prominent ventriculus terminalis might provide an anatomical basis for the terminal syrinx, coexisting factors, such as spinal cord ischemia, and altered local,CSF dynamics, should be taken into consideration.2) Large cavitations should be drained via myelotomies. Small cysts (syrinx index of <40) should probably be left untreated,and the syrinx should be followed with serial MR imaging. 3) A better clinical outcome isachieved following successful decompression of the syrinx in addition to untethering the spinalcord.4) Inadequate dissection of subarachnoid adhesions resulted in enlargement of the syrinxcavity.