Minimal-invasive, image guided, 360-degree resection of ilio-lumbo-sacral ostechondroma, planned on the 3D model in a child with hereditary multiple ostechondroma (HMO).

Background: Hereditary Multiple Osteochondromas (HMO), previously known as Multiple Hereditary Exostoses (MHE), is a genetic disorder characterized by the formation of multiple, benign, exostoses (osteochondromas) growing from the metaphyseal region of long bones as well as from the axial skeleton. Lesions originating from the lumbar spine region are rare, and are most common growing from the posterior element of the vertebrae. HMO associated osteochondromas are difficult to treat due to continuous and incontrollable growth of these lesions and a lifetime risk for malignant transformation.

Case Report: We describe a case of a 16-year old patient with known HMO who developed a giant ilio-lumbo-sacral osteochondroma. The tumor protruded into the L4-S1 intraspinal foramina with exophytic expansion to the right psoas muscle and lumbar plexus with compression of the right common iliac vein. To plan and execute the resection and minimize the risk of complications, we used a 3D printed model of the lesion with intraabdominal vessels. The patient was operated during a two-stage procedure - first by mini-open, transabdominal, navigated resection of the lesion, followed by delayed posterior, mini-invasive, navigated resection. The outcome was uneventful and there were no signs of regrowth or malignant transformation during 4 years of follow-up.

Conclusion: We describe a 360-degree surgical resection with application of a 3D printed model, navigation, and mini-invasive techniques. Our report may be useful and inspire spine surgeons to apply similar techniques to treat complex spine lesions.