Selection of the Optimal Distal Fusion Level in Posterior Instrumentation and Fusion for Thoracic Hyperkyphosis

Abstract

The distal end of a fusion for thoracic hyperkyphosis should include the SSV. Levels that include the first lordotic vertebra but not the SSV are not always appropriate to prevent postoperative distal junctional kyphosis.

Selection of distal fusion level in posterior instrumentation and fusion of Scheuermann kyphosis: is fusion to sagittal stable vertebra necessary?

“…DJK is a major instrumentation-related complication after the surgical correction of kyphotic deformities, and its reported incidence is around 0-28 % [4,5,7]. According to the recent studies, DJK is mainly attributed to junctional ligamentous disruption, too much correction of the deformity and failure to incorporate the appropriate vertebra into the fusion.…”

“…FLV was chosen as the vertebra just caudal to the first lordotic disk (the most proximal thoracolumbar or lumbar disk with C5°of anterior opening) below the kyphotic deformity. SSV was established based on the description by Cho et al (the most proximal thoracolumbar or lumbar vertebra intersected by the posterior sacral vertical line) [7]. DJA was measured between the superior endplate of the lowest instrumented vertebra and the inferior endplate of the adjacent distal vertebra.…”

“…On the other hand, the exact criteria to avoid distal junctional kyphosis (DJK) have been controversial. Some authors suggest that distal fusion level must include the first lordotic vertebra (FLV) [2,[4][5][6], while other studies recommend fusion to the sagittal stable vertebra (SSV) [7,10]. The purpose of this study was to evaluate the selection of distal fusion level in SK surgery by investigating the relationship between SSV, FLV, and the lowest instrumented vertebra (LIV), in terms of DJK occurrence.…”

“…A common and wellknown complication is development of junctional kyphosis which can occur proximal or distal to the instrumentation [4][5][6]. DJK is seen up to 28 % after SK surgery [4,7] and can be a source of pain and imbalance. It is not detectable clinically and is not predictable during preoperative radiographic evaluation [8].…”

Surgical treatment of Scheuermann’s kyphosis using a combined antero-posterior strategy and pedicle screw constructs: efficacy, radiographic and clinical outcomes in 111 cases

“…In other studies, fusion length averaged 11 [36], 12 [29] and 13 levels [28] or was not reported [3,8]. There is ongoing discussion regarding the appropriate end level to spare motion segments while lowering the risk of PJK and DJK [37]. Regarding UIV, there seems to be agreement concerning inclusion of at least the proximal end vertebra [24].…”