Selection of Fusion Levels in Adolescent Idiopathic Scoliosis Using Fulcrum Bending Prediction

Abstract

The new objective strategy for determining fusion levels using FB radiographs is safe and effective. With considering the flexibility of the curve, we are able to save levels distally in over 60% of patients. This strategy takes into account the power of modern instrumentation.

Selective fusion for adolescent idiopathic scoliosis: a review of current operative strategy

“…King et al [25] identified the stable and neutral vertebra as the appropriate area to end a fusion for false double major curve. The majority of studies have shown satisfactory outcomes when the LIV is at the stable and neutral vertebra [3,5,7,17,20,36,37]. One study showed a significantly increased risk of lumbar decompensation when the fusion did not end at the stable and neutral vertebra, and decompensation occurred at a rate of 22% [4].…”

“…As new instrumentation was introduced over the next few decades, the ability to correct patients' curves improved significantly. The technology has changed, but the goals of surgery for AIS remain the same: (1) halt curve progression and correct deformity, (2) maintain a balanced spine in the coronal and sagittal planes, (3) preserve as many mobile spinal segments as possible, and, (4) prevent surgical complications such as junctional kyphosis, adding-on, and revision surgery [2][3][4][5][6][7][8][9][10][11]. Since the publication of the landmark article by King et al [12], some double major curves have been identified as containing a structural and a compensatory component.…”

“…Recent studies have shown that more flexible compensatory curves are able to correct spontaneously after fusion of the structural curve [3-5, 7, 10, 17, 18, 22-27]. As pedicle screws began to be used in the thoracic spine, studies showed superior curve correction with all pedicle screw constructs due to the three column fixation of pedicle screws and greater ability to translate and derotate the spine [5,28]. Dobbs et al [3] in 2006 found that pedicle screws allowed for better curve correction than hooks for selective thoracic fusion.…”

Taking the shoulders and pelvis into account in the preoperative classification of idiopathic scoliosis in adolescents and young adults (a constructive critique of King’s and Lenke’s systems of classification)

“…For example, the King II type actually includes both ''pelvis included'' and ''pelvis excluded'' curves: when the two curves are both of the same grade, the pelvis is usually included. Some authors have used bending lumbar tests to help them decide which vertebrae should be instrumented but, since the lumbar curve is always more flexible than the thoracic one for anatomical reasons, the bending test can mask the contribution of the pelvis and result in strategic errors [12,19]. One might even say that when dealing with double thoracic and lumbar (thoracic predominant) ''pelvis included'' curves, the use of the bending lumbar test is the best possible way of getting it wrong.…”

Coronal deformity correction in adolescent idiopathic scoliosis patients using the fulcrum-bending radiograph: a prospective comparative analysis of the proximal thoracic, main thoracic, and thoracolumbar/lumbar curves

“…One of which is the fulcrum-bending radiograph (FBR). The FBR has been shown to allow the identification of structural changes, assist in the selection of fusion levels, and predict the degree of correction [1,[5][6][7].…”