Ventral anchoring of the conus medullaris: a new surgical technique preventing the recurrence of retethering after surgery for tethered spinal cord

Abstract Objective: Retethering is not an unusual operation for a congenital lumbosacral dysraphic spinal lesion. The present study aimed to assess a new surgical technique for preventing retethering. Surgical technique: After untethering the spinal cord, the pia mater or scar tissue at the caudal end of the conus medullaris is anchored to the ventral dura mater loosely using 8-0 thread, and the dura mater is closed directly. This technique is called ventral anchoring. Results: Ventral anchoring was performed in 15 patients (aged 5 to 37 years old, average age: 12.1 years old) between 2014 and 2021. All but one patient showed improvement or stabilization of the preoperative symptoms. No complication directly related to the procedure was observed. Postoperative MRI demonstrated that the dorsal subarachnoid space was restored in 14 patients but was undetectable or absent in three patients on follow-up MRI. No patients have experienced a recurrence of the tethered cord syndrome during the follow-up period. Conclusion: Ventral anchoring is effective for restoring the dorsal subarachnoid space after untethering the spinal cord. This preliminary study suggested that ventral anchoring has the potential to prevent the postoperative recurrence of tethered cord syndrome in patients with a congenital lumbosacral dysraphic spinal lesion.