Tandem Detethering: A Novel One-Stage Approach Combining Cervicothoracic Cord Release Followed by Filum Terminale Sectioning

<b>Background/Objectives</b>: We report a prospective series of five patients with symptomatic cervicothoracic spinal cord tethering from prior surgical interventions for acquired and congenital spinal pathologies. Each patient demonstrated incidental radiographic evidence of a low-lying conus or a fatty/thickened filum terminale (FT), suggesting concomitant symptomatic conus tethering as a potential contributor. Therefore, all underwent single-stage "tandem detethering", consisting of microsurgical release of the cervicothoracic pathology followed by FT resection. <b>Methods</b>: Patients' charts were reviewed for preoperative presentation, imaging, intraoperative findings, surgical details, FT pathology, and six-month outcomes. Results: Preoperative tethering occurred at sites of prior interventions: (i) thoracic arachnoid cyst decompression after Chiari surgery, (ii) cervical lipomyelomeningocele repair, (iii) thoracic ependymoma resection, (iv) syringosubarachnoid shunt placement, and (v) laminectomies for recurrent syrinx. Lumbar MRI demonstrated a low-lying conus in two patients and a fatty/thickened FT in four patients. Intraoperatively, all patients exhibited an abnormal FT (tight, fat-infiltrated, thickened, or dysplastic). No intraoperative complications or neuromonitoring abnormalities were observed. At six months, all patients demonstrated improvement in motor, sensory, pain, and urinary/bowel symptoms. Complications included two pseudomeningoceles requiring repair and one case of recurrent cauda tethering following FT resection. <b>Conclusions</b>: In patients with symptomatic cervicothoracic tethering, a concomitant low-lying conus or pathological FT may contribute to symptomatology by perpetuating biomechanical stress and, if not surgically addressed, may limit neurological recovery. This concept provides a rationale for considering tandem detethering under such circumstances.