Large terminal syringomyelia associated with terminal lipoma: mid- to long-term outcomes after tethered cord release

The management of large terminal syringomyelia (TS) at initial surgery varies in clinical practice, and outcome data stratified by spinal dysraphism subtype remain limited. We evaluated the mid- to long-term clinical course after tethered cord release (TCR) for large TS associated with terminal lipoma.

We retrospectively analyzed 12 patients with terminal lipoma (Morota Types 3-4) and large syrinx (syrinx index ≥ 0.5) who underwent TCR without routine additional syrinx procedures between 2012 and 2023. Patients with other spinal dysraphisms were excluded to evaluate a relatively homogeneous spinal dysraphism subtype. Radiological and clinical outcomes were assessed during follow-up.

Median MRI and clinical follow-up periods were 54 and 71 months, respectively. Postoperative syrinx reduction or resolution was observed in all patients. Neurological symptoms improved in symptomatic patients. One patient developed a new postoperative deficit, and no patient required reoperation for retethering or syrinx progression. The syrinx index decreased significantly from 0.67 to 0.00 (p = 0.00049). One holocord case underwent intraoperative minimal puncture for temporary pressure relief rather than definitive drainage.

In terminal lipoma-associated large TS, TCR without routine additional syrinx procedures was associated with a favorable clinical course during follow-up. These findings provide subtype-specific outcome data that may assist surgical decision-making, particularly when considering the need for additional syrinx procedures at initial surgery.

Not applicable.