Real-time ultrasound-guided spinal anesthesia in patients with a challenging spinal anatomy: two case reports.

Spinal anesthesia may be challenging in patients with poorly palpable surface landmarks or abnormal spinal anatomy. Pre-procedural ultrasound imaging of the lumbar spine can help by providing additional anatomical information, thus permitting a more accurate estimation of the appropriate needle insertion site and trajectory. However, actual needle insertion in the pre-puncture ultrasound-assisted technique remains a 'blind' procedure. We describe two patients with an abnormal spinal anatomy in whom ultrasound-assisted spinal anesthesia was unsuccessful. Successful dural puncture was subsequently achieved using a technique of real-time ultrasound-guided spinal anesthesia. This may be a useful option in patients in whom landmark-guided and ultrasound-assisted techniques have failed.