summary Scheuermann's Kyphosis is a rigid form of spinal kyphosis caused by anterior wedging of >5 degrees across three consecutive vertebrae, most commonly in the thoracic spine. Diagnosis is made with standard and hyperextension lateral radiographs of the thoracic spine. Treatment can be observation or surgical management depending on the severity of kyphosis, presence of neurological deficits, and/or persistent and progressive pain. Epidemiology Incidence 0.4% to 8.3% most common type of structural kyphosis in adolescents typical age of onset is from 10-12 years age with small subset adult onset Demographics M:F ratio between 2:1 and 7:1 Anatomic location usually in thoracic spine less common form occurs in thoracolumbar/lumbar region (see below) Etiology Pathoanatomy exact pathophysiology is unknown but several theories osteonecrosis of anterior apophyseal ring herniation of disc material leading to loss of anterior disc height relative osteoporosis leading to compression deformity altered biomechanics leading to anterior wedging and subsequent growth arrest most widely accepted theory suggests that the kyphosis and vertebral wedging are caused by a developmental error in collagen aggregation which results in an abnormal end plate Genetics autosomal dominant inheritance pattern now accepted Associated conditions orthopaedic manifestations Lumbar hyperlordosis spondylolysis in lumbar region (33%) scoliosis (33%) dural cysts compensatory tightness of anterior shoulder, hamstrings, and iliopsoas muscle non-orthopaedic manifestations pulmonary issues in curves exceeding 100 degrees Classification Thoracic Scheuermann's Kyphosis most common form curve from T1/2 to T12/L1 with apex between T6-T8 better prognosis Thoracolumbar/lumbar Scheuermann's Kyphosis far less common form curve from T4/5 to L2/3 with apex near the thoracolumbar junction associated with increased back pain more likely to be progressive and symptomatic more irregular end-plates noted on radiographs, less vertebral body wedging Presentation Symptoms may complain of thoracic or lumbar pain cosmetic concerns Physical exam increased kyphosis which has a sharper angulation when bending forwards normal thoracic kyphosis is between 20 degrees and 45 degrees may have a compensatory hyperlordosis of the cervical and/or lumbar spine tight hamstrings, iliopsoas, and anterior shoulder neurological deficits rare but need full examination Imaging Radiographs recommended AP and lateral spine findings anterior wedging across three consecutive vertebrae >5 degree disc narrowing endplate irregularities Schmorl's nodes (herniation of disc into vertebral endplate) scoliosis compensatory hyperlordosis spondylolysis on dedicated lumbar films if patient has low back pain determine sagittal balance by dropping C7 plumb line hyperextension lateral radiograph supine lateral radiograph with patient lying in hyperextension over a bolster can help differentiate from postural kyphosis Scheuermann's kyphosis usually relatively inflexible on bending radiograph CT scan usually not needed MRI controversial as to whether it is indicated prior to surgery to look for associated disc herniation, epidural cyst, spinal cord abnormalities, and spinal stenosis will show vertebral wedging, dehydrated discs, and Schmorl's nodes (herniation of disc into vertebral endplate) any neurological symptom or deficit warrants evaluation with MRI Treatment Nonoperative stretching, observation, physical therapy indications kyphosis < 60° and asymptomatic (mild symptoms) most patients fall in this group and can be treated with observation alone modalities physical therapy postural improvement exercises and back extensor strengthening core muscle strengthening for patients with spondylolysis limited effectiveness bracing with an extension-type orthosis (Jewitt type - with high chest pad) indications kyphosis 60°-80° most effective in those with growth remaining outcomes patient compliance is often an issue most favorable in curves <65°, correction of >15° in brace usually does not lead to correction but can stop progression Operative posterior spinal fusion ± osteotomy ± anterior release indications kyphosis > 75 degrees neurologic deficit spinal cord compression severe pain in adults techniques Smith-Petersen osteotomy best for long sweeping, global kyphosis less than the typical 10° sagittal plane correction per level given ridigity anterior release technique of the past, rarely done now due to pedicle screw constructs fusion dual rod instrumentation usually performed outcomes studies show 60-90% improvement of pain with surgery (no correlation with amount of correction) studies suggest residual curves >75° lead to worse functional outcomes Techniques PSF with dual rod instrumentation +/- anterior release and interbody fusion approach posterior midline to thoracic spine arthrodesis current recommendation is to include entire kyphotic Cobb angle and stop distally to include the first stable sagittal vertebra (first vertebra bisected by the posterior sacral vertical line) previously stopped distally at first lordotic disc but had high incidence of distal junctional kyphosis fixation technique usually a combination of pedicle screws and hooks intra canal hooks may be dangerous at apex of curve as they can potentially compress spinal cord do not always have to instrument at apex correction technique Cantelever - usally two rods placed in top anchors then brought down to bottom pedicle screws Compression across posterior anchors posterior spine shortening technique of Ponte indicated in stiff curves where correction is needed done by removing spinous processes at apex, ligamentum flavum, and performing facet joint resection goal is to obtain correction to final kyphosis of 40-50° in situ bending usually difficult to do and not helpful anterior release and fusion thorascopic anterior discectomy may help avoid morbidity of thoracotomy, but usually not needed neuromonitoring motor and sensory evoked potentials must be monitored intraoperative Complications Neurologic complications reported rate of 0.6-0.8% higher than idiopathic scoliosis corrective surgeries typically due to spinal cord stretching/lengthening (need to ensure there is enough posterior column shortening) neuromonitoring changes warrant reversal of correction overall incidence of complications does not differ between anterior/posterior versus posterior alone procedure Distal junctional kyphosis occurs in 20-30% of patient avoid by making proper selection of fusion levels (use the first stable sagittal vertebra) avoid overcorrection (correction should not exceed 50% of original curve) Proximal junctional kyphosis typically secondary to overcorrection and negative sagittal balance less common that distal junctional kyphosis Pseudarthrosis Hardware failure Loss of correction Superior mesenteric artery syndrome rare Prognosis Back pain in adults that very rarely limits daily activities (mild curves with a mean of 71 degrees) Curves >75 degrees are likely to cause severe thoracic pain Studies suggest at least some progression in 80% of patients but not often to severe deformity Long-standing compensatory lumbar hyperlordosis may lead to lumbar spondylolysis