The potential impact of intraoperative neurophysiological monitoring on neurological function outcomes after postnatal spina bifida repair.

Introduction: The management of open neural tube defects (ONTD) has significantly improved with fetal surgery, but many children remain ineligible for fetal therapy. This study assesses the impact of intraoperative neurophysiological monitoring (IONM) during postnatal myelomeningocele (MMC) repair and its potential to optimize functional outcomes.

Patients and methods: Seven newborns with thoracolumbar or lumbar MMC underwent postnatal surgical repair using IONM. Neuromonitoring included motor-evoked potentials (MEP), sensory-evoked potentials (SEP), electromyography (EMG), and bulbocavernosus reflex (BCR). Preoperative neurological assessments were compared with postnatal outcomes at 2 years, along with anatomical levels on MRI and IONM results.

Results: At birth, 6 of 7 newborns showed better functional levels than expected by the anatomical level of the ONTD in fetal MRI. Intraoperative EMG responses were normal in all but one patient, but only 30% of patients had normal MEP and SEP responses. IONM was useful to detect undue mechanical stress during ONTD repair surgery and intraoperative identification of functional nerve roots. Neurological function deteriorated in the early postoperative period but stabilized at a level above the anatomical MRI level in 85% of the patients by 2 years of age.

Conclusion: IONM in postnatal ONTD repair is a safe and valuable tool that has the potential to increase surgical safety by detecting undue mechanical stress to the neural structure. Standardized postnatal management strategies, including the use of IONM, should be refined. Further studies are necessary to evaluate the prognostic value of EMG during postnatal surgery and its potential to result in better long-term outcome by preventing additional intraoperative damage.