Don t turn your back on Scheuermann s Kyphosis

Transcription

1 Don t turn your back on Scheuermann s Kyphosis Stefan Parent, MD, PhD Ste-Justine Hospital Université de Montréal Academic Chair in Pediatric Spinal Deformities

2 Disclosures Depuy Synthes spine (a), Canadian Institutes of Health Research (a), Scoliosis Research Society (a), POSNA Biomet Spine Research Grant (a), Natural Sciences and Engineering Research Council of Canada (a), Orthopedic Research and Education Foundation (a), Setting Scoliosis Straight Foundation (a), Medtronic (b), Depuy Synthes spine Canada (b), EOS-Imaging (b), Spinologics (c) Royalties: EOS-Imaging (a) (b) (c) (d) (e) Grants/Research Support Consultant Stock/Shareholder Speakers Bureau Other Financial Support

3 Normal Range: degrees Significant measurement error (6-10 degrees)* Location of kyphotic deformity more important than the absolute number of degrees Thoracolumbar cosmetically more visible than thoracic and is typically more painful *Stotts, Smith, D Astous et al. Spine 2002

4 Postural Scheuermann s Congenital Dysplasias (i.e. achondroplasia) Neuromuscular Post-laminectomy Iatrogenic Trauma Infection

5 Scheuermann s kyphosis Danish radiologist Scheuermann, 1921 osteochondritis deformans juvenilis dorsi Definition: 5 vertebral wedging 3 consecutive vertebrae Endplate irregularities, narrowed discs, thickened ALL and Schmorl s nodes (intraosseous disk herniation) Prevalence 1-10% Male:female ratio close to 1:1

6 Histology Osteochondrosis of the spine: defective growth of cartilage endplate leading to disorganized endochondral ossification

7 Uncertain etiology Genetic prediposition Affecting collagen and chondrocytes 74% heritability in twins (autosomal dominant inheritance) Mechanical hyperpressure on growth cartilage Weak mechanical interface between stiff bone and resilient disc More active individual (manual labor, sports) High BMI, overweight Short sternum Avascular necrosis of endplates Hormonal (growth hormone) Nutritional (vitamine D deficiency)

8 Mid-Thoracic Thoracolumbar 89

9 67 SK patients avge F/U 32 yrs Age and gender matched controls SK more intense BP, less strenuous jobs, less trunk strength and ROM Pulmonary decline Kyphosis >100, especially with Thoracic apex

10 Greater back pain (72% vs 38%) Lower activity job requirements Less range of spinal motion (extension) Lower extension strength Compared to age and sex matched controls

11 No differences noted for: Level of education Days absent from work Extent of pain interfering with ADL s Self-esteem Social limitations Medications for back pain Level of participation in recreational activity Little preoccupation with their physical appearance

12 MRI Indicated preoperatively to rule out potential thoracic disk herniation, epidural cyst, or spinal stenosis which may cause neurologic symptoms at the time of deformity correction

13 Management Exercise/PT Bracing Risser 0-3 Milwaukee gold standard Surgery >70 Refractory pain Cosmesis/self esteem

14 Sacro-Pelvic Unit Morphology Pelvic incidence (PI) is specific and constant for each adult individual and is independent of the sagittal orientation of the pelvis Ref: Legaye, Duval-Beaupère et al., Eur Spine J, 1998

15 PT= Pelvic Tilt SS= Sacral Slope

16 Compensation mechanism through pelvic retroversion

17 Pelvic incidence and sagittal balance in Scheuermann s Kyphosis «Pelvic incidence: a fundamental pelvic parameter for threedimensional regulation of spinal sagittal curves.» Legaye J et al. Eur Spine J 1998;7(2): Increasing lordosis and kyphosis could intuitively relate to abnormal (High) PI This is not a normal state High PI can be seen in normal population

18 Recent papers

19 Sagittal parameters and Scheuermann s Kyphosis Lower PI and PT compared to normal population 32.0 vs. 45.0, P < for PI 0.2 vs. 11.9, P < for PT For Thoracic Scheuermann s Kyphosis Cervical lordosis, thoracic kyphosis and lumbar lordosis all increased For Thoraco-Lumbar Scheuermann s kyphosis Lower thoracic kyphosis and lumbar lordosis

20 Pelvic parameters and SK Lower PI than normal adults (40 ) No correlation between PI, LL and TK

21 Pelvic parameters and correction loss No correlation between correction loss and pre-operative pelvic parameters

22 Quality of life Patients with SK had lower scores in all domains of the SRS-22 than patients with AIS Patients with a thoracolumbar apex reported worse pain scores than those with a thoracic apex Negative correlations were found between all domains and the T5-T12 kyphosis

23 Surgery Rarely needed: no evidence showing clear benefit of surgery vs. no surgery Best indicated for immature patients with progressive kyphosis > 80 and failure of conservative treatment Other indications: Refractory pain Loss of sagittal balance Neurologic deficit Improvement in QOL not related to correction

24 Sagittal Stable Vertebra Concept

25 SSV The most proximal lumbar vertebral body touched by the vertical line from the posterior-superior coner of the sacrum Should be included in the fusion

26 Surgery Basic principles Kyphosis = shortening of anterior column Risk of sudden stretching of anterior column and spinal cord during correction of kyperkyphosis = risk of paraplegia Need to shorten posterior column Need for intraoperative neuromonitoring

27 Surgery Most commonly posterior-only with Ponte osteotomies Less blood loss and shorter surgery than combined anterior-posterior with similar correction Similar opening of disc anteriorly without anterior approach Anterior release useful if ossification of ALL or bridging anterior osteophytes

28 Current surgical trends Posterior-only approach Wide posterior releases Ponte osteotomies Shortening procedure Anterior-posterior approach Longer More complications Similar rates of PJK and DJK Less loss of correction

29 Scheuermann s long kyphosis large radius flexible balanced

30 Current surgical technique Level selection Include at least 1st lordotic level distally Include UEV (Cobb) Include sagittal Stable vertebra Wide surgical exposure Instrumentation planning Screw at every level may preclude compression

31 Geck MJ, Macagno A, Ponte A, Shufflebarger HL. The Ponte procedure: posterior only treatment of Scheuermann's kyphosis using segmental posterior shortening and pedicle screw instrumentation. J Spinal Disord Tech.2007;20:

32 Current surgical techique Ponte osteotomies Shortening the spinal column May protect spinal cord from «overstretching» over stiff kyphosis

33 Current surgical technique Wide posterior-release and Ponte Screw placement

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35 Current surgical technique Two rods attached proximally Compression proximally over several levels THEN Cantilever two rods to distal screws / implants Reduction screws may be beneficial distally to help in reduction

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37 T1 2 L2

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39 Complications of surgery Overall rate of complications from SRS Morbidity and Mortality Committee: 12% Wound infection Implant-related complications Acute neurologic deficit (1.9%) Similar complications posterior-only vs. AP Junctional kyphosis Failure to include all levels Overcorrection

40 Risk of PJK and DJK PJK occured in 32% of patients Magnitude directly related to pelvic incidence However, PJK seemed also to correlate directly to residual thoracic kyphosis DJK occured in 5% of patients All patients that developped DJK were fused proximal to the SSV

41 Recommendations If High PI, patient can probably accomodate larger kyphosis and doesn t need a very agressive correction Over-correction could probably lead to development of PJK if high PI If Low PI, correction should be aimed at correcting toward more normal values and decreasing final kyphosis Under-correction seems to correlate with PJK

42 LOW PI Higher PI

43 Conclusion Scheuermann s kyphosis is a disease of the sagittal plane Sagittal profile does not necessarily follow normal pattern Risk of junctionnal kyphosis is real Surgery produces good outcomes WHEN needed. Posterior approach is current approach of choice.