MRI-Assisted Planning for Spinal Anesthesia in a Pregnant Woman with Radiographic Spina Bifida Occulta: A Case Report

Background and Clinical Significance: Spina bifida occulta may be associated with occult spinal dysraphism, including a low-lying conus medullaris or tethered cord, which can increase the risk of neurological injury during neuraxial anesthesia. We report a case in which preoperative magnetic resonance imaging (MRI) and lumbar ultrasonography supported individualized planning for spinal anesthesia for cesarean delivery. Case Presentation: A 31-year-old woman at 37 weeks of gestation was scheduled for elective cesarean delivery because of marginal placenta previa. She had chronic low back pain, and previous lumbar radiography and computed tomography had demonstrated radiographic spina bifida occulta. Preoperative lumbar MRI confirmed that the conus medullaris terminated normally at L1 and showed no evidence of tethered cord, filum terminale thickening, spinal lipoma, or abnormalities at the planned L3/4 puncture site. Based on these findings and discussion with the patient, spinal anesthesia was selected. Immediately before the procedure, lumbar ultrasonography was used to identify the L3/4 interspace, visualize the posterior complex, and estimate needle depth. Spinal anesthesia was successfully achieved with a 27-gauge pencil-point needle and intrathecal hyperbaric bupivacaine, morphine, and fentanyl. Cesarean delivery was completed without new neurological deficits or major anesthetic complications. Conclusions: Preprocedural MRI and lumbar ultrasonography supported individualized anatomical assessment and anesthetic planning in this patient.