Introduction: Tethered cord (TC) syndrome (TCS) is a complex constellation of neurologic, orthopedic, urologic, and anorectal symptoms. Patients are heterogenous in symptomatic presentation and radiographic findings. Classic MRI stigmata of TCS include thickened or fatty filum, lipomas, and a low-lying conus. In challenging cases when supine imaging does not clearly identify tethering in patients with symptoms of TCS, particularly in those recurrent symptoms after prior surgery, we have employed prone magnetic resonance imaging (MRI) to try and eliminate false negative MRI reports and identify patients in whom repeat surgery may ameliorate symptoms.
Methods: Demographic, clinic, radiographic, and operative information was collected for each patient who underwent prone MR at New York Presbyterian Hospital-Weill Cornell Medical Center from 2022 to 2024. Prone MRI were reviewed by board certified neuro-radiologist and pediatric neurosurgeons. Institutional board review was obtained for this study.
Results: 13 patients were included in the study (range 8 to 60, average 30 years) with female predominance (77%). Ten patients initially met criteria for TCS with confirmation of “classic” radiographic findings. In 9/10 patients prone imaging was successfully utilized to identify re-tethering that had been suspected based on clinical suspicions. Common measurements for prone MR include change in distance between the cord and posterior disc supine compared to prone, position dependent changes of conus, and ventral motion of nerve roots and conus. Focal dorsal tethering of clumps of nerve roots at the surgical site were common etiology. 8 of the 9 patients (88.8%; age range 8-44; 6 males and 2 females) with re-tethering identified on prone imaging were offered and underwent surgical intervention.
Conclusion : Prone patient positioning is a useful radiographic adjuvant to supine lumbar MR for patients with suspected recurrent TCS. It can be utilized in patients to identify tethering or re-tethering in cases when supine MR results are negative or equivocal but symptom recurrence warrants further investigation. In a limited initial series, patients in whom prone imaging was used to offer surgery in 88.8%.
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