TETHERED CORD SYNDROME IN OCCULT SPINAL DYSRAPHISM - TIMING AND OUTCOME OF SURGICAL RELEASE

Objective: To investigate the influence of neurosurgical intervention on the appearance of upper motor neuron (UMN) signs in newborns diagno sed with occult spinal dysraphism and tethered cord (TC) during the fi rst month of Life. Methods: A prospective study (1990 to 1996) of 22 c onsecutive newborns with occult spinal dysraphism monitored for the ap pearance of UMN signs. Untethering was performed when neurologic or ur odynamic investigation indicated the presence of UMN dysfunction. Resu lts: Of 22 patients, 10 remained free of UMN symptoms during follow-up (mean, 67 +/- 22 months). Untethering was performed in 12 of 22 patie nts because of the presence of UMN symptoms. In 7 of these 12 patients , there was a documented asymptomatic period of 13 +/- 11 months befor e the onset of UMN symptoms. Untethering at a mean age of 18 +/- 17 mo nths restored normal neurologic and urinary function in all patients ( mean postoperative follow-up, 25 +/- 16 months). Of the 12 children, 5 presented with UMN signs at birth. In these children, untethering was performed at a mean age of 9 +/- 5 months. In two of these five patie nts, UMN symptoms did not resolve after surgery, and ongoing conservat ive bladder treatment was required (mean follow-up, 37 +/- 14 months). In none of the 12 operated children did signs of retethering occur. C onclusions: A significant number (10/22) of children born with occult spinal dysraphism and TC did not develop UMN symptoms during follow-up ; neurosurgical correction after the appearance of an UMN sign restore d normal neurologic and urinary function in all children; and untether ing in children presenting at birth with UMN symptoms resulted in poor er outcome.