Comparison of treatment and outcome between Myelomeningocele and Myeloschisis after open fetal repair - experience after first 200 cases

Background: Open fetal repair of spina bifida, encompassing myelomeningocele (MMC) and myeloschisis (MS), aims to mitigate neurological damage via early intervention. While both entities share a pathophysiological foundation, their clinical presentations and surgical challenges differ. Objective: To compare postnatal outcomes, particularly wound closure, CSF diversion, and motor function, between fetal MMC and MS repairs at a single high-volume center. Methods: This retrospective cohort study eventually included 187 patients who underwent open fetal SB repair between 2010 and 2023. Perioperative data, wound-related complications, need for CSF diversion, and 3-year motor outcomes were analyzed and compared between MMC and MS subtypes. Results: Of the included patients, 130 (69.5%) presented with MMC and 57 (30.5%) MS. Primary skin closure was achieved significantly more often in MMC (than MS (91.5% vs. 47.4%, p < 0.001), while the overall need for any postnatal surgical intervention was significantly higher in MS compared to MMC (17.5% vs. 3.1%, p = 0.001). Deeper closure techniques (myofascial and dural repair) showed no differences between groups. Cerebrospinal fluid (CSF) diversion within the first year was required in 33% of all cases. Prenatal limb movement was more frequently observed in MS. At 3 years, ambulation outcomes were comparable, with over 75% (MMC: 75.3%, MS: 78.0%) of patients in both groups achieving community walking status. Conclusion: Myeloschisis and myelomeningocele are distinct entities within open spina bifida, with MS posing greater technical challenges for skin closure but suggesting a more favorable prenatal neurological profile. Despite these differences, long-term outcomes regarding motor function and CSF management were equivalent, underscoring the effectiveness of fetal surgery across both subtypes.