Part I Amy L. McIntosh, MD Pediatric Orthopedic Surgeon Mayo Clinic Rochester, Minnesota

Orthopedic Aspects of Stickler Syndrome Amy L. McIntosh, MD Pediatric Orthopedic Surgeon Mayo Clinic Rochester, Minnesota

Stickler Syndrome Aka: Hereditary Progressive Arthro- ophthalmopathy 1 st described (1965): Gunnar Stickler Pediatrician

Gunnar B. Stickler German born: (June 1925) Peterskirchen, Bavaria. Graduated from medical school in Munich (1949) Immigrated to US (1951). Appointed to the staff of the Mayo Clinic (1957). Chairman of Pediatrics (1969) Retired (1989)

What we knew in 1965 SS inherited in an autosomal dominant pattern. Eye findings: Myopia Retinal detachment Joint findings: Abnormal development of the articular surface Premature degenerative changes hypermobility

What we know today Underlying etiology of SS appears to be changes in genes encoding collagen subunits –COL2A1 –COL11A1 come together to form collagen strands –COL11A2 Collagen strands are the scaffolds for many connective tissues

Cartilage Bundles of collagen form together to provide a structure around cells that form cartilage

What does cartilage do in our bodies? 1.Initial model of bones when born seems to be unaffected in Stickler Syndrome 2.Growth of bones in children (aka: growth plate) 3.Smooth, lubricating surface in our joints

Cartilage Growth Plate Femur Tibia

Growth Plate in Stickler Syndrome Normal“Stickler”Normal Diagram Garofalo et al PNAS 1991

Lubrication and Cushioning of Joints

Result – Mild Bone Shape Abnormalities Round Ball Round Socket (Round) Ball Oval Socket

How does this add up for Stickler Syndrome? Spondyloepiphyseal dysplasia –Spondylo = spine –Epiphyseal = ends (joints) of bones –Dysplasia = alteration in shape or structure

What do we know about skeletal changes in Stickler Syndrome? Majority of our data comes from the NIH / NHGRI natural history and molecular studies Cross sectional study of patients seen at the NIH Clinical Center Rose: Spine2001

Diagnostic Utility of Skeletal Analysis

Spine Analyzed thorocolumbar (chest and low back vertebra) in 53 patients –Age 1-70 –24 families –Correlated findings with back pain

Scoliosis (30%) Abnormal curve of the spine in the frontal plane –Present in 1/3 rd of patients –Equally present in children and adults –Generally mild – only 1/18 patients required surgery

Kyphosis (43%) Abnormal rounding of the back Present in 43% of patients –Adolescents and adults Not associated with back pain

Schmorl’s Nodes / Endplate Abnormalities

Endplate Abnormalities (74%) Caused by weakened bone endplates Seen in 74% overall –Seem to come with age –Present in 94% of adults Associated with back pain

Spondylolysis/Spondylolisthesis (11%)

Spine Only one adult patient was free of spine abnormalities Back pain present in 2/3rds of patients > 5 yo –Associated with adult age, endplate abnormalities, and Schmorl’s nodes

Spine: Treatment What do we make of this? 1.Most DO NOT require surgical treatment 2.These findings can help in the recognition and diagnosis of Stickler Syndrome 3.Treatment will be discussed more later.