Adolescent Idiopathic Scoliosis in a 17-year-old Boy
The patient is a 17-year-old boy who presented with adolescent idiopathic scoliosis and worsening truncal deformity. He is otherwise healthy and his neurological examination was normal.
The patient indicated increasing activity-related discomfort over the lumbar convexity over the prior 6 months and significant waistline changes.
Normal neurological examination including motor, sensory, reflex examination of the lower extremities, normal abdominal reflexes, negative ankle clonus, and down-going Babinski reflex.
Angle of Trunk Rotation (Inclinometer)
- Thoracic: 5-degrees
- Thoracolumbar: 27-degrees
Pulmonary Function Tests
- FVC: 4.1, 100%
- FEV1: 2.95, 83%
- It was suspected the values are somewhat overestimated due to the fact that standing height measurements were taken rather than arm span which would have compensated for the loss of height associated with marked spinal curvature.
- Thoracic curvature: 71-degrees corrects to 54-degrees on supine bending
- Thoracolumbar curvature: 91-degrees corrects to 73-degrees on supine bending
Figure 1. Standing, AP
Figure 2. Standing, lateral
Figure 3. Side bending
Figure 4. Side bending
Pre-operative Clinical Photographs
Rib hump measurements were 5-degrees thoracic, 27-degrees thoracolumbar
Pre-operative Surface Topography
Adolescent idiopathic scoliosis with thoracic and lumbar trunk rotation
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Posterior spinal fusion with segmental instrumentation (T3-L3), including posterior column (Ponte) osteotomies (T5-T11, T12-L3), lumbar lateral interbody releases, and fusion combined with rib section (left side, 12th rib) via a TLIF approach of T12-L1, L1-L2, and L2-L3.
Estimated blood loss was 4500 cc. The patient received 1500 cc of cell saver blood, 3000 cc of crystalloid, 1500 cc of Lactated Ringer's, 2 units of fresh frozen plasma, and 3 units of packed red blood cells.
The patient was out of bed to chair on post-op day 1, walking by day 2, and discharged home on day 4. The patient was restricted from bending, lifting, and twisting activities for 3 months and allowed to begin non-contact sports at 3 months. The patient was encouraged to walk immediately after surgery.
Surgeon's Treatment Rationale
This patient had a highly progressive, severe adolescent idiopathic scoliosis with structural thoracolumbar and thoracic curvatures. The major curvature being the thoracolumbar curve, making this a Lenke Type 6CN (N for normal thoracic sagittal contour, C for the center sacral line lying outside of the apical lumbar vertebrae) in which both curvatures were very large and rigid. In light of the severity of the curvatures, and their relatively rapid progression, a screening MRI was done and was normal.
Curves of this magnitude were historically treated with anterior release and posterior instrumentation—at least for a thoracolumbar curvature over 90-degrees and not correcting to less than 70-degrees on flexibility testing. Supine bending x-rays were performed but a traction x-ray for curvature over 70-degrees may be a better choice to assess flexibility.
An important consideration for this patient is the distal level of fusion, which in such a severe curvature is often L4, especially given the fact that the center sacral vertical line does not even touch the L3 vertebrae. However, it is desirable to preserve motion segments and fusing to L3 versus L4 may be important in preserving the health of the remaining unfused motion segments.1
Anterior release/fusion and instrumentation have been historically associated with preservation of distal motion segments compared to posterior fusions particularly for thoracolumbar curvatures, although recent studies have shown no difference utilizing modern posterior techniques. In this case, given the severity of the curvature, its magnitude and rigidity, and the deviation of L3 from the midline, a more extensive release than the standard posterior column osteotomies often performed was done via multiple posterior-based annulectomies and disc debulking on the convexity in order to save a motion segment, and fuse to L3 versus L4, and to optimize correction. It is unknown whether a posterior procedure alone would have allowed similar correction and distal fusion level.
1 Auerbach JD, Lonner BS, Errico TJ, Freeman A, Goerke D, Beaubien BP. Quantification of intradiscal pressures below thoracolumbar spinal fusion constructs: Is there evidence to support "saving a level"? Spine. 2012;37(5):359-66.
Comparative pre- and post-operative images (Figs. 11, 12).
Post-operative Surface Topography
The patient's recovery was uneventful, and he returned to school 6-weeks after surgery. He will be able to begin to play sports 3-months post-operatively. Both the patient and his parents are delighted with the outcome.
This 17-year-old presented with a large and painful curve. The curve size and significant pain issues make the decision to recommend surgery appropriate. Dr. Lonner provides an excellent analysis of the curve pattern and the surgical choices available. Dr. Lonner's selection of posterior-only surgery certainly demonstrates the increasing appeal of this approach, as better posterior techniques are now routine.
The literature supports the conclusion that there is no longer any significant advantage to anterior/posterior surgery over posterior-only to achieve the goals of a balanced and stable correction, while limiting the distal extent of the fusion. What is somewhat unusual in this case is the number of Ponte osteotomies and convex annulotomies performed. This may have contributed to the loss of blood. However, one cannot argue with the result of being able to stop the fusion at L3 with this vertebra now well-contained in the stable zone.