Progression of terminal syrinx in occult spina bifida after untethering

Object: The association of spinal dysraphism and terminal syringomyelia is a well-known entity, and untethering with or without syrinx drainage is usually the surgery of choice. However, progression of the previously existing syrinx after an untethering procedure is an uncommon course. The objective of this study was to discuss the diagnostic, surgical, and follow-up consequences of such an occurrence. Methods: Four children with occult spina bifida associated with teminal syrinx at the time of initial presentation are included in this study. After the primary releasing procedure, all developed enlargement of the syrinx. Two of them were operated on for placement of a syringo-subarachnoid shunt, while the other two were followed up conservatively. One of the shunted patients also had a second releasing procedure. Conclusion: Progression of the pre-existing terminal syrinx after the primary untethering procedure should be kept in mind even in the absence of overt neurological progression.