A comparison of MRI appearance and surgical detethering rates between intrauterine and postnatal myelomeningocele closures: a single-center pilot matched cohort study.

Introduction: Intrauterine myelomeningocele repair (IUMR) and postnatal myelomeningocele repair (PNMR) differ in terms of both setting and surgical technique. A simplified technique in IUMR, in which a dural onlay is used followed by skin closure, has been adopted at our institution. The goal of this study was to compare the rates of clinical tethering in IUMR and PNMR patients, as well as to evaluate the appearance on MRI.

Methods: We conducted a retrospective review of 36 patients with MMC repaired at our institution, with 2:1 PNMR to IUMR matching based on lesion level. A pediatric neuroradiologist blinded to the clinical details reviewed the patients' lumbar spine MRIs for the distance from neural tissue to skin and the presence or absence of a syrinx. An EMR review was then done to evaluate for detethering procedures and need for CSF diversion.

Results: Mean age at MRI was 4.0 years and mean age at last follow-up was 6.1 years, with no significant difference between the PNMR and IUMR groups. There was no significant difference between groups in the distance from neural tissue to skin (PNMR 13.5 mm vs IUMR 17.6 mm; p = 0.5). There was no difference in need for detethering operations between groups (PNMR 12.5% vs IUMR 16.7%; RR 0.75; CI 0.1-5.1).

Conclusions: There was no significant difference between postnatal- and intrauterine-repaired myelomeningocele on MRI or in need for detethering operations. These results imply that a more straightforward and time-efficient IUMR closure technique does not lead to an increased rate of tethering when compared to the multilayered PNMR.