Proximal junctional kyphosis post tuberculous spine corrective surgery in paediatric patients

Retrospective case series. Proximal junctional kyphosis (PJK) is a well-recognised post-operative complication of deformity correction surgery. Our local tuberculosis (TB) endemic is responsible for severe kyphotic deformities. The most challenging is in the paediatric environment where powerful instrumentation is used in immature spines with more flexible disco-ligamentous structures than adults.

To establish the incidence of PJK and management thereof in our paediatric TB spine patients undergoing corrective surgery.

Twenty-seven consecutive paediatric patients undergoing fusion surgery for TB spine with 2-year follow-up were identified from our prospectively maintained database. Age at surgery was 8.0 years (2.5-17 ± 3.98) with 14 under the age of 7. Only anterior surgery was performed in 1, posterior only in 13 and combined in 13 with a total of 5 (1-11) levels fused.

Nine (33.3%) patients developed PJK (progression by >  = 10°) with an average progression of 16.2°(11-26 ± 5.42) compared the overall cohorts change of 5.1°(- 26-15 ± 9.24). Although not reaching statistical significance, there was a trend to higher incidence of PJK when instrumented, 8/20 (40%) compared to 1/7 (14.3%), more so in posterior only surgery compared to combined, 6/13 (46.2%) compared to 3/13 (23.1%) and when the UIV was at T7 or above, 7/17 (41.2%) compared to 2/10 (20%). There was a higher PJK rate when the number of levels fused was >  = 6, 7/12 (58.3%) compared to 2/10 (p = 0.014), when the kyphotic correction was more than 39º, 5/8 (62.5%) compared to 4/19 (21.1%) (p = 0.07) and when <  = 7 years old, 7/14 (50%) compared to 2/13 (15.4%) (p = 0.05). Two of the nine PJK cases required revision for junctional failure.

In paediatric TB kyphosis correction, there was a 33% incidence of PJK with 2/9 requiring revision surgery for proximal failure. Our data suggest that this incidence of PJK was related to the magnitude of correction, the number of levels fused with a trend of increase in higher UIVs, posterior approach and instrumentation.This suggests that in young children, one should be cautious of overzealous kyphosis correction due to the risk of catastrophic proximal junctional failure.