Cohort comparison study of neurosurgical procedures after closure of myelomeningocele by fetal surgery versus by neonatal surgery in patients in the national spina bifida patient registry

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G Worley¹, R Greenberg¹, B Dicianno², J Jasien¹, R Adams³, J Wiener¹

¹Duke University Medical Center, Durham, NC, USA; ²University of Pittsburgh Medical Center, Pittsburgh, PA, USA; ³UTSW Medical Center, Texas Scottish Rite Hospital, Dallas, TX, USA

Background and Objective(s): The Management of Myelomeningocele (MMC) Study (MoMS) was a randomized, controlled trial of fetal surgery (FS) versus neonatal surgery (NS) for closure of MMC. Outcomes were assessed at age ≥ 12 months old. FS had significantly lower rates of ventriculoperitoneal shunt (VPS) insertion for hydrocephalus and of VPS revision, but had a trend toward a greater rate of tethered cord surgery (TCS)., The Chiari II hindbrain malformation, a cause of brainstem dysfunction in MMC, was less common and less severe on MRI in FS. The NSBPR has 19 participating SB Clinic sites with 6,184 patients with MMC enrolled through 2016.

Study Design: Cohort comparison study.

Study Participants & Setting: Of the 242 patients in the NSBPR who had FS, 201 were ≥ 12 months old at last visit and could be matched for age ± 3 months and for SB Clinic site of care to at least one and up to three NS patients who were also ≥ 12 months at last visit, (n=439).

Materials/Methods: Outcomes were VPS insertion, VPS revision, Chiari II hindbrain surgery for brainstem dysfunction, and tethered cord surgery (TCS). Wilcoxon and Chi square tests were used.

Results: FS had lower rates than NS of VPS insertion (44% vs. 79%; p< 0.001), VPS revision (24% vs. 43%; p< 0.001), and Chiari II surgery (4% vs.8%; p=0.045), but there was a trend toward a higher rate of TCS in FS (24% vs.18%; p=0.07).

Conclusions/Significance: This large, multicenter cohort comparison study with unbiased ascertainment of outcomes provides independent confirmation of the findings of the MoMS RCT that FS is associated with lower rates than NS of VPS insertion and VPS revision and adds that FS is also associated with a lower rate of Chiari II surgery, Similarly, we too found a trend toward a higher rate of TCS in FS.