Real Time Ultrasound Guided Spinal Anesthesia in Elderly Patients

the probe will be placed in a parasagittal plane to identify the articular processes then the sacrum will be identified. The probe will be moved cephalad in the parasagittal axis until the identification of the target lumbar interspaces L2-L3, L3-L4 or L4-L5. Once the appropriate lumbar interspace is identified, the probe will be tilted 45 degree towards the midline into a parasagittal oblique view. The needle will be inserted in plane from the caudal end of the ultrasound transducer with its tip directed towards the interlaminar space under real-time in-plane US guidance.

the transducer will be applied in the parasagittal plane, and after identification of the intervertebral level, the probe will be rotated 90 degrees into a transverse orientation and centered on the neuraxial midline in a way to align the beam with the interspinous and interlaminar space and thus to get a paramedian transverse interlaminar view. The needle will be inserted in plane from the lateral end of the ultrasound transducer with its tip directed towards the medial border of the articular process.