S1 Iliosacral screw (ISS) fixation : Technique

Indications

1. Sacro-iliac joint disruptions
2. Sacral fractures

Entry point

Anterior in S1 body and inferior to the overlapping iliac cortical density (ICDs) in true lateral projection

Trajectory

1. Inlet view:
   1. Close to the anterior alar cortex but leave a good space anteriorly and avoid skirting alar cortex anteriorly
2. Outlet view:
   1. Cranial to ventral foramen of the 1^st sacral nerve root
   1. Try to stay low in the body staying close to the roof of the foramen below

Dangers

1. Perforation of wire posteriorly: Injury to contents of spinal canal
2. Perforation of sacral foramina: Injury to exiting nerve root
3. Screws passing too anteriorly or superiorly in S1 body (superior to ICD): Injury to L5 and obturator nerve

Dr. Sulabh Kumar Shrestha, MS Orthopedics

He is the section editor of Orthopedics in Epomedicine. He searches for and share simpler ways to make complicated medical topics simple. He also loves writing poetry, listening and playing music. He is currently pursuing Fellowship in Hip, Pelvi-acetabulum and Arthroplasty at B&B Hospital.